TY - CONF A1 - Lenke, Karoline A1 - Trappe, Volker T1 - Damage evolution in short fibre reinforced polyamide caused by biaxial loading N2 - The multiaxial fatigue damage behaviour of short fibre reinforced polyamide 6 is analysed on injection moulded tube samples. In parallel with the fatigue tests, the damage state is evaluated nondestructively by X-ray refraction analysis which detects inner surfaces by the variation of electron density. By applying X-ray refraction analysis and a model based on by GÜNZEL the micro damage evolution can be separated into fibre matrix debonding and matrix-Micro cracking. T2 - ECCM16 - 16th European conference on composite materials CY - Seville, Spain DA - 22.06.2014 KW - Short fibre reinforced composites KW - Multiaxial loading KW - Non-destructive testing KW - Damage evolution KW - Damage state PY - 2014 SN - 978-84-616-9798-4 N1 - Geburtsname von Lenke, Karoline: Metzkes, K. - Birth name of Lenke, Karoline: Metzkes, K. SP - 1 EP - 8 AN - OPUS4-31042 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Myrach, Philipp A1 - Krankenhagen, Rainer A1 - Röllig, Mathias A1 - Steinfurth, Henrik T1 - Detection and characterization of defects in isotropic and anisotropic structures using lockin thermography N2 - Lockin thermography is a well-suited method for the characterization of structures made of both metal and fiber reinforced plastic. In most cases, only phase images are analyzed, although the amplitude images might contain useful information as well. Thus, systematic studies of lockin thermography are presented, assessing amplitude and phase images for the detection and quantification of defects in isotropic (steel) and anisotropic (carbon fiber reinforced plastic) materials. Characterized defects are flat bottom holes with different diameters and various remaining wall thicknesses as well as crossed notches at different depths. The excitation frequency was varied while keeping the number of analyzed excitation periods nearly constant for each material. The data analysis was focused on the detectability of the defects both in the amplitude and phase images, including the determination of the signal-to-noise ratio and of the spatial resolution. As a result, the limits of defect detectability and spatial resolution are given for each material KW - Lockin-Thermography KW - Non-destructive testing KW - Steel KW - Carbon-fiber-reinforced plastics KW - Amplitude images KW - Phase images KW - Signal-to-noise ratio KW - Lateral resolution PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-352394 DO - https://doi.org/10.3390/jimaging1010220 SN - 2313-433X VL - 1 SP - 220 EP - 248 PB - MDPI CY - Basel AN - OPUS4-35239 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiggenhauser, Herbert A1 - Niederleithinger, Ernst T1 - NDT-CE 2015: International symposium non-nestructive testing in civil engineering N2 - The legend continued: The International Symposium NonDestructive Testing in Civil Engineering (NDT-CE) had returned to Berlin. The Bundesanstalt für Materialforschung und -prüfung (BAM) and the Technical University of Berlin (TUB) hosted this prestigious event in the industrial landmark building Peter-Behrens-Halle and the Test Site Technical Safety (TTS) in Horstwalde in September 2015. Almost 300 participants from more than 35 countries gathered to present recent research, exchange knowledge and to lest the newest equipment in NDT-CE. This symposium, held regularly in various locations all over the world, was organized for the third time in Berlin and is by far the largest of its kind. KW - Non-destructive testing KW - Civil engineering KW - Conference PY - 2015 SN - 0934-6554 IS - 3 SP - 53 EP - 54 PB - Deutsche Geophysikalische Gesellschaft CY - Münster AN - OPUS4-35097 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Puthiyaveettil, N. A1 - Thomas, K. R. A1 - Myrach, Philipp A1 - Ziegler, Mathias A1 - Rajagopal, P. A1 - Balasubramaniamam, K. T1 - Defect detection in steel bars up to 600 °C using laser line thermography N2 - Crack detection in steel bars at high surface temperatures is a critical problem in any manufacturing industry. Surface breaking cracks are the major problems during the billet casting. Many NDT techniques are proven its capability in crack detection at room temperature. Here, we are demonstrating the possibility of exposure of cracks using laser line thermography at higher surface temperatures (up to 600 °C). A continuous-wave (CW) laser is used to excite the sample kept at higher surface temperatures. The temperature distribution over the sample due to the laser line scanning is captured using a temperature calibrated infrared (IR) thermal camera. The response of the sample temperature in crack detection is investigated using a validated FE model. The impact of the oxide layer in crack detection is investigated by using two types of samples; one without any oxide layer and the second is with the oxide layer. The influence of laser power in the detection of defects at high temperatures is studied. 3D numerical models were developed for the cases; when the sample is with oxide layer and without any oxide layer for a better understanding of physics. The surface temperature rise due to laser heating is higher for the scaled sample compared to the no-scale sample. The presence of the oxide layer above the parent metal will reduce the reflectivity of the surface. Lower reflectivity will lead to increased absorption of incident energy so that the surface temperature rise will be higher than the surface with no scale. Thermal contrast linearly depends on laser power, which means higher laser power will increase the defect detectability even at a higher surface temperature. KW - Laser thermography KW - High temperature KW - Modeling KW - Surface cracks KW - Non-destructive testing PY - 2020 DO - https://doi.org/10.1016/j.infrared.2020.103565 SN - 1350-4495 VL - 111 SP - 103565 PB - Elsevier B.V. AN - OPUS4-51573 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pech May, Nelson Wilbur A1 - Paul, A. A1 - Ziegler, Mathias T1 - Pulse-compression laser thermography using a modified Barker code: Enhanced detection of subsurface defects N2 - Pulse-compression thermography is an emerging technique that has shown versatility by combination of pulsed and lock-in thermography. Accordingly, several aspects of this technique are still unexplored, and some others not fully developed yet. Barker codes were widely used in radar applications due to their simplicity and their optimum autocorrelation function. Nevertheless, applications were limited by the amplitude of the sidelobes present in the autocorrelation function and therefore, several filters have been developed which aim to reduce the sidelobes. However, the filters usually depend on empirical parameters which must be determined for each application. A better alternative would improve the applicability of the Barker codes. In this work, we further develop the pulse-compression thermography technique by introducing a 13-bit modified Barker code (mBC): This allows to drastically reduce the sidelobes characteristic of the 13-bit Barker code (BC). Consequently, the thermographic impulse response, obtained by cross-correlation, is almost free of such sidelobes. Deeper defects become easier to detect in comparison with using a 13-bit Barker code. Numerical simulations using the finite element method are used for comparison and experimental measurements are performed in a sample of steel grade St 37 with machined notches of three different depths: 2 mm, 4 mm and 6 mm. T2 - SPIE Defense + Commercial Sensing 2021 CY - Online meeting DA - 13.04.2021 KW - Pulse-compression laser thermography KW - Barker codes KW - Non-destructive testing PY - 2021 DO - https://doi.org/10.1117/12.2586078 SN - 0277-786X VL - 11743 SP - 1 EP - 11 PB - SPIE CY - Bellingham, Wash. AN - OPUS4-53247 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schweitzer, T. A1 - Hörmann, M. A1 - Bühling, Benjamin A1 - Bobusch, B. T1 - Switching Action of a Bistable Fluidic Amplifier for Ultrasonic Testing N2 - Air-coupled ultrasonic testing is widely used in the industry for the non-destructive testing of compound materials. It provides a fast and efficient way to inspect large concrete civil infrastructures for damage that might lead to catastrophic failure. Due to the large penetration depths required for concrete structures, the use of traditional piezoelectric transducer requires high power electric systems. In this study, a novel fluidic transducer based on a bistable fluidic amplifier is investigated. Previous experiments have shown that the switching action of the device produces a high-power broadband ultrasonic signal. This study will provide further insight into the switching behaviour of the fluidic switch. Therefore, parametric CFD simulations based on compressible supersonic RANS simulations were performed, varying the inlet pressure and velocity profiles for the control flow. Switching times are analyzed with different methods, and it was found that These are mostly independent of the slope of the velocity profile at the control port. Furthermore, it was found that an inversely proportional relationship exists between flow velocity in the throat and the switching time. The results agree with the theoretical background established by experimental studies that can be found in the literature. KW - Ultrasound KW - Non-destructive testing KW - Fluidic devices KW - Computational fluid dynamics KW - Concrete KW - Bistable fluidic amplifier PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525115 DO - https://doi.org/10.3390/fluids6050171 SN - 2311-5521 VL - 6 IS - 5 SP - 171 PB - MDPI CY - Basel, Switzerland AN - OPUS4-52511 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kling e Silva, L. A1 - Almeida, G. A1 - Kadoke, Daniel A1 - Daum, Werner A1 - Ribeiro Pereira, G. T1 - Automation of pipe defect detection and characterization by structured light N2 - High quality tubular products are essential to the oil and gas industry. Quality control during their production focuses on the non-destructive detection of surface defects. The structured light technique is a candidate for the challenge to detect, monitor and evaluate such defects in real-time. In the present study the automatic processing of structured light measurements is performed and validated. The algorithm for the automatic Analysis of inspection data has an advantage over current data evaluation methods based on individual assessments of operators. KW - Non-destructive testing KW - Data processing KW - Defect evaluation KW - Materials evaluation KW - Structured light scanning (SLS) PY - 2021 DO - https://doi.org/10.1515/mt-2020-0008 SN - 0033-8230 VL - 63 IS - 1 SP - 55 EP - 61 PB - Walter de Gruyter GmbH CY - Berlin/ Boston AN - OPUS4-52124 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dymkin, G. Y. A1 - Konshina, V. N. A1 - Jaenisch, Gerd-Rüdiger T1 - Оперативная характеристика обнаружения как метод оценки достоверности неразрушающего контроля T1 - Requirements for Accreditation Appraisal of NDT Laboratories in Nuclear Power Industry N2 - The operational characteristics of detection have been successfully applied for many years in assessing the reliability of non-destructive testing. The main problems for their use, as in the application of any of the methods for assessing the reliability, are the lack of information about the actual defect situation and the limited number of defects in the samples of the objects of control. An additional problem of constructing an operational characteristic of detection is the lack of information about the size of defects and the lack of a universal size for various types of defects. The article summarizes the experience of constructing operational characteristics based on the results of ultrasonic testing. N2 - Оперативные характеристики обнаружения в течение многих лет успешно применяют-ся при оценке достоверности неразрушающего контроля. Основными проблемами для их использования, как и при применении любого из методов оценки достоверности, яв-ляются отсутствие информации о действительной дефектной ситуации и ограниченное количество дефектов в образцах объектов контроля. Дополнительной проблемой постро-ения оперативной характеристики обнаружения является отсутствие информации о раз-мерах дефектов и отсутствие универсального размера для различных типов дефектов. В статье обобщён опыт построения оперативных характеристик по результатам ультра-звукового контроля. KW - Non-destructive testing KW - Reliability KW - Probability of detection KW - Operational characteristics KW - Comparative operational characteristics PY - 2021 DO - https://doi.org/https://doi.org/10.12737/1609-3178-2021-23-26 VL - 24 IS - 2 SP - 23 EP - 26 AN - OPUS4-53121 LA - rus AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zeipert, H. A1 - Claes, L. A1 - Johannesmann, S. A1 - Lugovtsova, Yevgeniya A1 - Nicolai, Marcel A1 - Prager, Jens A1 - Henning, Bernd ED - Jumar, U. T1 - An approach to adhesive bond characterisation using guided acoustic waves in multi-layered plates N2 - An approach for the non-destructive characterisation of adhesive bonds using guided ultrasonic waves is presented. Pulsed laser radiation is used to thermoacoustically excite broadband ultrasonic waves in a multi-layered sample, consisting of a metal plate adhesively joined to a polymeric layer using synthetic resin. The resulting signals are received by a purpose-built piezoelectric transducer. Varying the distance between excitation and detection yields spatio-temporal measurement data, from which the dispersive properties of the propagating waves can be inferred using a two-dimensional Fourier transform, assuming the plates to act as coupled waveguides. Coupled multi-layered waveguides show an effect referred to as mode repulsion, where the distance between certain modes in the frequency-wavenumber domain is assumed to be a measure of coupling strength. Measurements at different stages of curing of the adhesive layer are performed and evaluated. A comparison of the results shows changes in the dispersive properties, namely an increased modal bandwidth for the fully cured sample as well as an increased modal distance. KW - Adhesive bonding KW - Guided waves KW - Non-destructive testing KW - Ultrasound PY - 2021 DO - https://doi.org/10.1515/auto-2021-0089 VL - 69 IS - 11 SP - 962 EP - 969 PB - De Gruyter CY - Berlin/Boston AN - OPUS4-53762 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kruschwitz, Sabine A1 - Oesch, T. A1 - Mielentz, Frank A1 - Meinel, Dietmar A1 - Spyridis, P. T1 - Non-Destructive Multi-Method Assessment of Steel Fiber Orientation in Concrete N2 - Integration of fiber reinforcement in high-performance cementitious materials has become widely applied in many fields of construction. One of the most investigated advantages of steel Fiber reinforced concrete (SFRC) is the deceleration of crack growth and hence its improved sustainability. Additional benefits are associated with its structural properties, as fibers can significantly increase the ductility and the tensile strength of concrete. In some applications it is even possible to entirely replace the conventional reinforcement, leading to significant logistical and environmental benefits. Fiber reinforcement can, however, have critical disadvantages and even hinder the Performance of concrete, since it can induce an anisotropic material behavior of the mixture if the fibers are not appropriately oriented. For a safe use of SFRC in the future, reliable non-destructive testing (NDT) methods need to be identified to assess the fibers’ orientation in hardened concrete. In this study, ultrasonic material testing, electrical impedance testing, and X-ray computed tomography have been investigated for this purpose using specially produced samples with biased or random Fiber orientations. We demonstrate the capabilities of each of these NDT techniques for fiber orientation measurements and draw conclusions based on these results about the most promising areas for future research and development. KW - Spectral induced polarization KW - Steel fiber reiniforced concrete KW - Fiber orientation KW - Non-destructive testing KW - Micro-computed tomography KW - Ultrasound PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543520 DO - https://doi.org/10.3390/app12020697 VL - 12 IS - 2 SP - 1 EP - 14 PB - MDPI CY - Basel Switzerland AN - OPUS4-54352 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hauffen, J. C. A1 - Kästner, L. A1 - Ahmadi, Samim A1 - Jung, P. A1 - Caire, G. A1 - Ziegler, Mathias T1 - Learned block iterative shrinkage thresholding algorithm for photothermal super resolution imaging N2 - Block-sparse regularization is already well known in active thermal imaging and is used for multiple-measurement-based inverse problems. The main bottleneck of this method is the choice of regularization parameters which differs for each experiment. We show the benefits of using a learned block iterative shrinkage thresholding algorithm (LBISTA) that is able to learn the choice of regularization parameters, without the need to manually select them. In addition, LBISTA enables the determination of a suitable weight matrix to solve the underlying inverse problem. Therefore, in this paper we present LBISTA and compare it with state-of-the-art block iterative shrinkage thresholding using synthetically generated and experimental test data from active thermography for defect reconstruction. Our results show that the use of the learned block-sparse optimization approach provides smaller normalized mean square errors for a small fixed number of iterations. Thus, this allows us to improve the convergence speed and only needs a few iterations to generate accurate defect reconstruction in photothermal super-resolution imaging. KW - Thermography KW - Laser KW - Machine learning KW - Optimization KW - Non-destructive testing KW - NDT KW - Neural network KW - Defect reconstruction KW - Block-sparsity KW - Active thermal imaging KW - Regularization KW - Laser thermography PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554598 DO - https://doi.org/10.3390/s22155533 SN - 1424-8220 VL - 22 IS - 15 SP - 1 EP - 15 PB - MDPI CY - Basel AN - OPUS4-55459 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Blankschän, M. A1 - Kanzler, D. A1 - Bertovic, Marija A1 - Rosenthal, Martina A1 - Liebich, R. T1 - Influence of illuminance on indication detectability during visual testing N2 - Visually detecting irregularities on components is a complex process, influenced by physical, technical, and human factors. Current standards mainly focus on illuminance, demanding highest accuracy for it, without providing scientific justification. In this research, 63 inspectors visually inspected forgings, with and without crack-like indications. The influence of illuminance on probability of detection was investigated. Therefore, illuminance was varied in three steps (200 lx, 350 lx, 500 lx). Human factors (e.g., experience, motivation) were recorded by using questionnaires. The results show no significant difference in probability of detection between the three illuminance levels. Equal probability of detection rates could be achieved at illuminances below and at the required threshold (500 lx). A difference in illuminance was found between the measurement point and the test area of the respective participant. This leads to higher assumed illuminance than present on the component. Compared with the measurement accuracy of the used illuminance meter, none of these deviations could be used to explain the similar results at different illuminance. The fact that illuminance has a significant influence in detecting indications has been disproven for this case. Whether human factors can provide explanation for the results remains unclear. This will be investigated in further research. KW - Illuminance KW - Non-destructive testing KW - Probability of detection KW - Reliability KW - Visual inspection PY - 2022 DO - https://doi.org/10.1515/mt-2022-0112 VL - 64 IS - 10 SP - 1532 EP - 1543 PB - De Gruyter AN - OPUS4-56019 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scherr, J. F. A1 - Kollofrath, J. A1 - Popovics, J. S. A1 - Bühling, Benjamin A1 - Grosse, C. U. T1 - Detection of Delaminations in Concrete Plates Using a Laser Ablation Impact Echo Technique N2 - This study investigates the non-destructive detection of delaminations in concrete plates using non-contact laser ablation, instead of the conventional hammer excitation, as part of the impact echo method. We performed tests on five concrete specimens of different sizes, two of which contained artificial delaminations. A range of steel ball hammers was used as reference impulse sources, the responses of which were compared with wave excitation generated by a 7 ns pulsed 1064 nm Nd:YAG laser with 150 mJ pulse energy. Signals were recorded by surface-mounted accelerometers and two contactless methods: microphones and a laser Doppler vibrometer. The laser generates frequencies across a broad range of frequencies (0 to 150 kHz) but with much less energy than the hammers' narrower frequency spectra; the laser pulse energy transferred into the specimen is 0.07 mJ, corresponding to about 0.5 ‰ of the impulse source energy. Because of this, the thick intact plates' characteristic thickness stretch resonance frequency can be reliably detected by the hammer excitations but not when using laser excitation. However, the laser can excite low-frequency flexural vibration modes over a shallow delamination at 3 cm depth. The low-frequency flexural vibration results are verified by numerical natural frequency analysis. KW - Concrete testing KW - Defect detection KW - Lamb waves KW - Impact echo KW - Non-destructive testing KW - Vibration PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567932 DO - https://doi.org/10.1007/s10921-022-00921-x SN - 0195-9298 VL - 42 IS - 1 SP - 1 EP - 14 PB - Springer AN - OPUS4-56793 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Ballio, F. A1 - Chatzi, E. A1 - Cigada, A. A1 - Darò, P. A1 - Elfgren, L. A1 - Gentile, C. A1 - Górski, M. A1 - Küttenbaum, Stefan A1 - Limongelli, M. P. A1 - Mancini, G. A1 - Oliveira, S. A1 - Rasol, M. A1 - Schmidt, F. A1 - Shan, J. A1 - Sousa, H. A1 - Torrent, R. A1 - Ueda, T. A1 - Verstrynge, E. T1 - Chapter 6: Case studies N2 - This chapter contains a selection of case studies that show the implementation of the methods and tools that have been described in the previous chaprters of fib Bulletin 109 on actual large-scale structures. KW - Structural engineering KW - Structural Health Monitoring KW - Non-destructive testing KW - Static and dynamic reassessment KW - Existing structures PY - 2023 SN - 978-2-88394-172-4 DO - https://doi.org/10.35789/fib.BULL.0109.Ch06 SN - 1562-3610 VL - fib Bulletin 109 SP - 104 EP - 126 PB - Fédération internationale du béton (fib) CY - Lausanne AN - OPUS4-59341 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Barzegar, M. A1 - Lugovtsova, Yevgeniya A1 - Bulling, Jannis A1 - Mishurova, Tatiana A1 - Pasadas, D. A1 - Ribeiro, A. A1 - Ramos, H. T1 - Automatic improved-resolution imaging of composite adhesive joints using time-frequency-wavenumber filtering applied to ultrasonic guided wavefields N2 - This paper presents an automatic damage imaging technique by employing a signal processing approach based on applying hierarchically clustered filters across different domains. The technique involves time-frequency-wavenumber filter banks which are applied sequentially to ultrasonic guided wave (UGW) data. The study is conducted for a single lap joint composite specimen with a special focus on small voids which were formed due to manual adhesive component mixing. UGW data are acquired with a 3D Scanning Laser Doppler Vibrometer (LDV) over the scan area of the bonded plate. UGWs are excited at the central frequency of 100 kHz by a single piezoelectric transducer mounted on the surface of the single plate. Within each domain of time, frequency, and wavenumber, four filters are designed which results in 64 distinct filtered wavefields. From each filtered wavefield, an image is obtained by using root-mean-square (RMS) calculation of the signals. The obtained results are then combined to create a final, improved-resolution image of the scan area. The final image is compared to the image obtained through RMS calculation of full wavefield with interpolation through Delaunay triangulation and the image obtained by X-ray radiography. The results show that the smallest void that could be detected has a diameter of 2.14 mm. T2 - 2023 IEEE International Ultrasonics Symposium (IUS) CY - Montreal, QC, Canada DA - 03.09.2023 KW - Adhesive joints KW - Ultrasonic guided waves KW - Laser Doppler vibrometer KW - Damage imaging KW - Non-destructive testing KW - Porosity analysis PY - 2023 DO - https://doi.org/10.1109/IUS51837.2023.10307423 SP - 1 EP - 4 PB - IEEE AN - OPUS4-58795 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Küttenbaum, Stefan A1 - Kainz, C. A1 - Braml, T. ED - Matos, J.C. T1 - Non-destructively Measurable Quantities Relevant to Reliability Assessment of Existing Concrete Bridges – Case Studies N2 - In reliability assessment of existing bridges, collected information about the structure can be utilized to modify partial safety factors and to refine characteristic values individually. In this way, uncertainties covered in initial calculation models and arising from assumptions can be reduced as well as biases identified and corrected. This allows for more realistic assessments and more appropriate decisions on actions to be taken. However, the on-site observation of information is generally associated with certain costs. For this reason, an efficient data-supported reassessment requires that only the individually relevant testing tasks are solved. Additional sensitivity analyses can further be used to specify the requirements on certain inspections, such as the testing result quality to be achieved, in order to avoid too imprecise or too expensive measurements on-site. In this contribution, the methodology for the demand-actuated definition of measurement objectives is demonstrated using the example of non-destructive concrete testing methods and findings from reassessments of two prestressed concrete bridges. Each case study includes the semi-probabilistic identification of structural weak points in ultimate and serviceability limit states, a comparison with respective probabilistic sensitivity analyses, and the subsequent derivation of parameters that are a) measurable and b) highly relevant in the individual reliability analyses. KW - Reliability KW - Assessment KW - Existing structures KW - Non-destructive testing PY - 2024 SN - 978-3-031-60270-2 DO - https://doi.org/10.1007/978-3-031-60271-9_18 VL - 494 SP - 209 EP - 219 PB - Springer CY - Cham AN - OPUS4-60613 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yagdjian, H. A1 - Lecompagnon, Julien A1 - Hirsch, Philipp Daniel A1 - Ziegler, Mathias A1 - Gurka, M. T1 - Application of the thermal shock response spectrum (TSRS) methodology to various forms of heat sources by pulse thermography and comparison by using a rotating line scan contour search algorithm N2 - In this paper, we propose a novel contour search algorithm (CSA) for image processing. Its efficacy is evaluated through a comparative analysis with established techniques such as Canny Edge and Snakes: Active contour models, utilizing infrared thermography (IRT) images. Based on the new CSA, we investigate the influence of different pulse shapes on the IRT post-processing methodology, particularly focusing on the thermal shock response spectrum (TSRS), using two different heat sources: xenon flash lamps and a laser. Moreover, this allows for a more precise quantitative comparison of the TSRS with existing IRT post-processing techniques, including pulse phase thermography and thermal signal reconstruction, concerning the detection of defects in composite materials, particularly in carbon fiber-reinforced polymer. A quantitative comparison was performed using the Tanimoto criterion and signal-to-noise ratio. A more detailed analysis is conducted to identify inherent limitations and potential benefits of the new TSRS methodology. We further investigate and experimentally confirm our previous finding on the qualitative correlation between the one-dimensional thermal N-layer model and test data from the TSRS optimization process for defect determination. This correlation can eliminate the time-consuming optimization step, making TSRS a more attractive alternative to common IRT methods and enhancing the quantitative description of defects. KW - Thermography KW - Non-destructive testing KW - NDT KW - Defect identification KW - Laser KW - Contour search PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615056 DO - https://doi.org/10.1063/5.0232015 SN - 1089-7550 VL - 136 IS - 175101 SP - 1 EP - 20 PB - AIP Publishing AN - OPUS4-61505 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krankenhagen, Rainer A1 - Maierhofer, Christiane T1 - Comparison of concepts for a point-shaped energy density detector after flash lamp excitation N2 - The paper describes investigations and Research work in order to develop a simple sensor for the quantification of spectral broadband energy Dissipation of flash lamps at any point in space. Such Flash lamps are often used as energy source during active thermography testing (TT). Here, the temperature transient of the sensor surface has to be recorded by the infrared camera that is already present. During the following data evaluation, the energy input into the investigated specimen can be determined. Two opposite concepts were considered: thermal thick and thermal thin probes. The direct comparison shows advantages for thermal thick probes based on the physics of thermal balance processes. KW - Flash thermography KW - Non-destructive testing KW - Flash lamp KW - Energy dissipation KW - Energy sensor PY - 2016 DO - https://doi.org/10.3139/120.110939 SN - 0025-5300 VL - 58 IS - 10 SP - 887 EP - 893 PB - Carl Hanser Verlag CY - München AN - OPUS4-37650 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hakim, I. A1 - Schumacher, David A1 - Sundar, V. A1 - Donaldson, S. A1 - Creuz, A. A1 - Schneider, R. A1 - Keller, J. A1 - Browning, C. A1 - May, D. A1 - Abo Ras, M. A1 - Meyendorf, N. ED - Chimenti, D. E. ED - Bond, L. J. T1 - Volume imaging NDE and serial sectioning of carbon fiber composites N2 - A composite material is a combination of two or more materials with very different mechanical, thermal and electrical properties. The various forms of composite materials, due to their high material properties, are widely used as structural materials in the aviation, space, marine, automobile, and sports industries. However, some defects like voids, delamination, or inhomogeneous fiber distribution that form during the fabricating processes of composites can seriously affect the mechanical properties of the composite material. In this study, several imaging NDE techniques such as: thermography, high frequency eddy current, ultrasonic, x-ray radiography, x-ray laminography, and high resolution x-ray CT were conducted to characterize the microstructure of carbon fiber composites. Then, a 3D analysis was implemented by the destructive technique of serial sectioning for the same sample tested by the NDE methods. To better analyze the results of this work and extract a clear volume image for all features and defects contained in the composite material, an intensive comparison was conducted among hundreds of 3D-NDE and multi serial sections’ scan images showing the microstructure variation. T2 - 44TH ANNUAL REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION CY - Provo, Utah, USA DA - 16.07.2017 KW - Carbon fiber reinforced polymers KW - Non-destructive testing KW - Thermography KW - Eddy current KW - Ultrasound KW - X-ray radiography KW - X-ray laminography KW - X-ray computed tomography KW - Serial sectioning PY - 2018 DO - https://doi.org/10.1063/1.5031590 VL - 1949 SP - 120003-1 EP - 120003-10 PB - AIP Publishing AN - OPUS4-45173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schumacher, David A1 - Sharma, R. A1 - Grager, J.-C. A1 - Schrapp, M. T1 - Scatter and beam hardening reduction in industrial computed tomography using photon counting detectors N2 - Photon counting detectors (PCD) offer new possibilities for x-ray micro computed tomography (CT) in the field of non-destructive testing. For large and/or dense objects with high atomic numbers the problem of scattered radiation and beam hardening severely influences the image quality. This work shows that using an energy discriminating PCD based on CdTe allows to address these problems by intrinsically reducing both the influence of scattering and beam hardening. Based on 2D-radiographic measurements it is shown that by energy thresholding the influence of scattered radiation can be reduced by up to in case of a PCD compared to a conventional energy-integrating detector (EID). To demonstrate the capabilities of a PCD in reducing beam hardening, cupping artefacts are analyzed quantitatively. The PCD results show that the higher the energy threshold is set, the lower the cupping effect emerges. But since numerous beam hardening correction algorithms exist, the results of the PCD are compared to EID results corrected by common techniques. Nevertheless, the highest energy thresholds yield lower cupping artefacts than any of the applied correction algorithms. As an example of a potential industrial CT application, a turbine blade is investigated by CT. The inner structure of the turbine blade allows for comparing the image quality between PCD and EID in terms of absolute contrast, as well as normalized signal-to-noise and contrast-to-noise ratio. Where the absolute contrast can be improved by raising the energy thresholds of the PCD, it is found that due to lower statistics the normalized contrast-to-noise-ratio could not be improved compared to the EID. These results might change to the contrary when discarding pre-filtering of the x-ray spectra and thus allowing more low-energy photons to reach the detectors. Despite still being in the early phase in technological progress, PCDs already allow to improve CT image quality compared to conventional detectors in terms of scatter and beam hardening reduction. KW - X-ray computed tomography KW - Photon counting detector KW - CdTe sensor KW - Non-destructive testing KW - Beam hardening KW - Scattered radiation PY - 2018 UR - http://iopscience.iop.org/article/10.1088/1361-6501/aabef7/meta DO - https://doi.org/10.1088/1361-6501/aabef7 SN - 1361-6501 VL - 29 IS - 7 SP - 075101, 1 EP - 12 PB - IOP Publishing CY - Bristol, UK AN - OPUS4-44959 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, David A1 - Meyendorf, N. A1 - Hakim, I. A1 - Ewert, Uwe ED - Chimenti, D. E. ED - Bond, L. J. T1 - Defect recognition in CFRP components using various NDT methods within a smart manufacturing process N2 - The manufacturing process of carbon fiber reinforced polymer (CFRP) components is gaining a more and more significant role when looking at the increasing amount of CFRPs used in industries today. The monitoring of the manufacturing process and hence the reliability of the manufactured products, is one of the major challenges we need to face in the near future. Common defects which arise during manufacturing process are e.g. porosity and voids which may lead to delaminations during operation and under load. To find irregularities and classify them as possible defects in an early stage of the manufacturing process is of high importance for the safety and reliability of the finished products, as well as of significant impact from an economical point of view. In this study we compare various NDT methods which were applied to similar CFRP laminate samples in order to detect and characterize regions of defective volume. Besides ultrasound, thermography and eddy current, different X-ray methods like radiography, laminography and computed tomography are used to investigate the samples. These methods are compared with the intention to evaluate their capability to reliably detect and characterize defective volume. Beyond the detection and evaluation of defects, we also investigate possibilities to combine various NDT methods within a smart manufacturing process in which the decision which method shall be applied is inherent within the process. Is it possible to design an in-line or at-line testing process which can recognize defects reliably and reduce testing time and costs? This study aims to show up opportunities of designing a smart NDT process synchronized to the production based on the concepts of smart production (Industry 4.0). A set of defective CFRP laminate samples and different NDT methods were used to demonstrate how effective defects are recognized and how communication between interconnected NDT sensors and the manufacturing process could be organized. T2 - 44TH ANNUAL REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION CY - Provo, Utah, USA DA - 16.07.2017 KW - Carbon fiber reinforced polymers KW - Non-destructive testing KW - Smart industry (4.0) KW - Ultrasound KW - Laminography KW - Serial sectioning KW - Computed tompgraphy PY - 2018 SN - 978-0-7354-1644-4 DO - https://doi.org/10.1063/1.5031521 SN - 0094-243X VL - 1949 SP - UNSP 020024, 1 EP - 11 PB - AIP Publishing AN - OPUS4-44773 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pelkner, Matthias A1 - Stegemann, Robert A1 - Sonntag, Nadja A1 - Pohl, Rainer A1 - Kreutzbruck, Marc T1 - Benefits of GMR sensors for high spatial resolution NDT applications N2 - Magneto resistance sensors like GMR (giant magneto resistance) or TMR (tunnel magneto resistance) are widely used in industrial applications, examples are position measurement and read heads of hard disk drives. However, in case of non-destructive testing (NDT) applications these sensors, although their properties are outstanding like high spatial resolution, high field sensitivity, low cost and low energy consumption, never reached a technical transfer to an application beyond sci-entific scope. This paper deals with benefits of GMR/TMR sensors in terms of high spatial resolution testing for different NDT applica-tions. The first example demonstrates the preeminent advantages of MR-elements compared with conventional coils used in eddy current testing (ET). The probe comprises one-wire excitation with an array of MR elements. This led to a better spatial resolution in terms of neighboring defects. The second section concentrates on MFL-testing (magnetic flux leakage) with active field excitation during and before test-ing. The latter illustrated the capability of highly resolved crack detection of a crossed notch. This example is best suited to show the ability of tiny magnetic field sensors for magnetic material characterization of a sample surface. Another example is based on characterization of samples after tensile test. Here, no external field is applied. The magnetization is only changed due to external load and magnetostriction leading to a field signature which GMR sensors can resolve. This gives access to internal changes of the magnetization state of the sample under test. T2 - QNDE 2017 CY - Provo, Utah, USA DA - 16.07.2017 KW - GMR KW - Non-destructive testing KW - Sensor arrays KW - Spatial resolution PY - 2018 SN - 978-0-7354-1644-4 DO - https://doi.org/10.1063/1.5031535 SN - 0094-243X VL - 1949 SP - UNSP 040001, 1 EP - 10 AN - OPUS4-45050 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Léonard, Fabien A1 - Stein, J. A1 - Soutis, C. A1 - Withers, P. J. T1 - The quantification of impact damage distribution in composite laminates by analysis of X-ray computed tomograms N2 - One of the great strengths of X-ray computed tomography over conventional inspection methods (ultrasound, thermography, radiography) is that it can image damage in 3D. However for curved ordeformed composite panels it can be difficult to automatically ascribe the damage to specific plies or inter-ply interfaces. An X-ray computed tomography (CT) data processing methodology is developed to extract the through-thickness distribution of damage in curved or deformed composite panels. The method is applied to [(0°/90°)2]s carbon fibre reinforced polymer (CFRP) panels subjected low velocity impact damage (5 J up to 20 J) providing 3D ply-by-ply damage visualisation and analysis. Our distance transform approach allows slices to be taken that approximately follow the composite curvature allowing the impact damage to be separated, visualised and quantified in 3D on a ply-by-ply basis. In this way the interply delaminations have been mapped, showing characteristic peanut shaped delaminations with the major axis oriented with the fibres in the ply below the interface. This registry to the profile of the panel constitutes a significant improvement in our ability to characterise impact damage in composite laminates and extract relevant measurements from X-ray CT datasets. KW - Delamination KW - Impact behaviour KW - Non-destructive testing KW - X-ray computed tomography KW - Distance transform PY - 2017 UR - http://www.sciencedirect.com/science/article/pii/S0266353817307157?via%3Dihub DO - https://doi.org/10.1016/j.compscitech.2017.08.034 SN - 0266-3538 SN - 1879-1050 VL - 152 SP - 139 EP - 148 PB - Elsevier Ltd. AN - OPUS4-42556 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hempel, M. A1 - Ziegler, Mathias A1 - Schwirzke-Schaaf, S. A1 - Tomm, J.W. A1 - Jankowski, D. A1 - Schröder, D. T1 - Spectroscopic analysis of packaging concepts for high-power diode laser bars N2 - Double-side cooled high-power diode laser bars packaged by different techniques on different types of passive heat sinks are analyzed in terms of packaging-induced strain. Reference data from standard devices being single-side cooled only and packaged by conventional soft and hard soldering are also presented. Thermal profiling across the devices complements the results. The most suitable packaging architecture and technique for double-side cooled bars is identified. Measurements of the laser emission near field and electroluminescence pattern provide direct reference to the functionality of the devices. Furthermore, a type of cross calibration of the methods used for strain analysis is made, since all techniques are applied to the same set of bars. This involves micro photoluminescence, micro Raman, and degree-of-polarization electroluminescence spectroscopy. KW - Spectroscopy KW - Semiconductor laser KW - Thermography KW - High-power diode lasers KW - Non-destructive testing PY - 2012 DO - https://doi.org/10.1007/s00339-012-6799-4 SN - 0947-8396 VL - 107 IS - 2 SP - 371 EP - 377 PB - Springer CY - Berlin AN - OPUS4-25789 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bühling, Benjamin A1 - Maack, Stefan A1 - Schönsee, Eric A1 - Schweitzer, Thorge A1 - Strangfeld, Christoph T1 - Acoustic and flow data of fluidic and piezoelectric ultrasonic transducers N2 - This data article presents characteristic acoustic and flow data of a fluidic ultrasonic transducer as well as acoustic data of a commercial piezoelectric ultrasonic transducer used in non-destructive testing for civil engineering. The flow data has been acquired using hot-wire anemometry and a Pitot tube. The three-dimensional acoustic data of both devices has been acquired using a calibrated microphone. The distribution of characteristic acoustic properties of both transducers are extracted and given in addition to the raw data. The data presented in the article will be a valuable source for reference and validation, both for developing fluidic and alternate ultrasound generation technologies. Furthermore, they will give additional insight into the acoustic-flow interaction phenomena of high speed switching devices. This article is accompanying the paper Experimental Analysis of the Acoustic Field of an Ultrasonic Pulse Induced by a Fluidic Switch (Bühling et al., 2021) published in The Journal of the Acoustical Society of America, where the data is interpreted in detail and the rationale for characteristic sound properties of the fluidic transducer are given. KW - Ultrasound KW - Non-destructive testing KW - Air-coupled ultrasound KW - Fluidics KW - Acoustic-flow interaction KW - Piezoelectric transducer PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531308 DO - https://doi.org/10.1016/j.dib.2021.107280 VL - 38 SP - 1 EP - 8 PB - Elsevier CY - Amsterdam AN - OPUS4-53130 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bühling, Benjamin A1 - Küttenbaum, Stefan A1 - Maack, Stefan A1 - Strangfeld, Christoph T1 - Development of an Accurate and Robust Air-Coupled Ultrasonic Time-of-Flight Measurement Technique N2 - Ultrasonic time-of-flight (ToF) measurements enable the non-destructive characterization of material parameters as well as the reconstruction of scatterers inside a specimen. The time-consuming and potentially damaging procedure of applying a liquid couplant between specimen and transducer can be avoided by using air-coupled ultrasound. However, to obtain accurate ToF results, the waveform and travel time of the acoustic signal through the air, which are influenced by the ambient conditions, need to be considered. The placement of microphones as signal receivers is restricted to locations where they do not affect the sound field. This study presents a novel method for in-air ranging and ToF determination that is non-invasive and robust to changing ambient conditions or waveform variations. The in-air travel time was determined by utilizing the azimuthal directivity of a laser Doppler vibrometer operated in refracto-vibrometry (RV) mode. The time of entry of the acoustic signal was determined using the autocorrelation of the RV signal. The same signal was further used as a reference for determining the ToF through the specimen in transmission mode via cross-correlation. The derived signal processing procedure was verified in experiments on a polyamide specimen. Here, a ranging accuracy of <0.1 mm and a transmission ToF accuracy of 0.3μs were achieved. Thus, the proposed method enables fast and accurate non-invasive ToF measurements that do not require knowledge about transducer characteristics or ambient conditions. KW - Air-coupled ultrasound KW - Laser Doppler vibrometer KW - Refracto-vibrometry KW - Acousto-optic effect KW - Time-of-flight measurements KW - In-air ranging KW - Non-destructive testing PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544711 DO - https://doi.org/10.3390/s22062135 VL - 22 IS - 6 SP - 1 EP - 17 PB - MDPI CY - Basel, Switzerland AN - OPUS4-54471 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bühling, Benjamin A1 - Strangfeld, Christoph A1 - Maack, Stefan A1 - Schweitzer, T. T1 - Experimental analysis of the acoustic field of an ultrasonic pulse induced by a fluidic switch N2 - Ultrasonic inspection is a common tool for non-destructive testing in civil engineering (NDT-CE). Currently, transducers are coupled directly to the specimen surface, which makes the inspection time-consuming. Air-coupled ultrasound (ACU) transducers are more time-efficient but need a high pressure amplitude as the impedance mismatch between the air and the concrete is high and large penetration depth is needed for the inspection. Current approaches aim at eliminating the impedance mismatch between the transducer and the air to gain amplitude; however, they hardly fulfill the NDT-CE requirements. In this study, an alternative approach for ultrasound generation is presented: the signal is generated by a fluidic switch that rapidly injects a mass flow into the ambience. The acoustic field, the flow field, and their interaction are investigated. It is shown that the signal has dominant frequencies in the range of 35–60 kHz, and the amplitude is comparable to that of a commercial ACU transducer. KW - Air-coupled ultrasound KW - Non-destructive testing KW - Ultrasonic transducer KW - Acoustic-flow interaction PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523862 DO - https://doi.org/10.1121/10.0003937 VL - 149 IS - 4 SP - 2150 EP - 2158 AN - OPUS4-52386 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Küttenbaum, Stefan A1 - Braml, T. A1 - Heinze, M. A1 - Kainz, C. A1 - Keuser, M. A1 - Kotz, P. A1 - Lechner, T. A1 - Maack, Stefan A1 - Reinke, K.-D. A1 - Schulze, S. A1 - Soukup, A. A1 - Stettner, C. A1 - Taffe, A. A1 - Wöstmann, Jens T1 - Guideline on NDT-supported reliability assessment of existing structures - Current developments in Germany N2 - Information about an existing structure can be collected at certain costs to evaluate the reliability and condition as realistically as necessary. This information can be relevant or irrelevant, true or biased, precise or imprecise. The incorporation of relevant and quality-assessed measured information into reliability reassessment offers the chance to extend remaining lifetimes and support decision making about optimal actions or maintenance strategies. This paper shows recent developments in a national research project that aims to produce a guideline on the NDT-based, structure-specific modification of partial safety factors. The general methodology, results from recalculations according to the Eurocodes and metrologically solvable testing tasks relevant in the recalculation of the concrete bridges are shown and compared with the non-destructive testing methods applicable to concrete bridges. A case study is used to demonstrate that as-built drawings, in this case of the positions of tendons and shear reinforcement, can be verified using the radar method. KW - Non-destructive testing KW - Concrete bridges KW - Partial safety factor modification PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584862 DO - https://doi.org/10.1002/cepa.2168 SN - 2509-7075 VL - 6 IS - 5 SP - 537 EP - 543 PB - Ernst & Sohn CY - Berlin AN - OPUS4-58486 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bühling, Benjamin A1 - Maack, Stefan A1 - Strangfeld, Christoph T1 - Fluidic Ultrasound Generation for Non‐Destructive Testing N2 - AbstractAir‐coupled ultrasonic testing (ACU) is a pioneering technique in non‐destructive testing (NDT). While contact testing and fluid immersion testing are standard methods in many applications, the adoption of ACU is progressing slowly, especially in the low ultrasonic frequency range. A main reason for this development is the difficulty of generating high amplitude ultrasonic bursts with equipment that is robust enough to be applied outside a laboratory environment. This paper presents the fluidic ultrasonic transducer as a solution to this challenge. This novel aeroacoustic source uses the flow instability of a sonic jet in a bistable fluidic switch to generate ultrasonic bursts up to 60 kHz with a mean peak pressure of 320 Pa. The robust design allows operation in adverse environments, independent of the operating fluid. Non‐contact through‐transmission experiments are conducted on four materials and compared with the results of conventional transducers. For the first time, it is shown that the novel fluidic ultrasonic transducer provides a suitable acoustic signal for NDT tasks and has potential of furthering the implementation of ACU in industrial applications.This article is protected by copyright. All rights reserved KW - Aeroacoustics KW - Air-coupled ultrasound KW - Fluidics KW - Harsh environment KW - Laser Doppler vibrometer KW - Non-destructive testing PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594273 DO - https://doi.org/10.1002/adma.202311724 SN - 0935-9648 SP - 1 EP - 14 PB - Wiley AN - OPUS4-59427 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klewe, Tim A1 - Strangfeld, Christoph A1 - Ritzer, Tobias A1 - Kruschwitz, Sabine T1 - Combining Signal Features of Ground-Penetrating Radar to Classify Moisture Damage in Layered Building Floors N2 - To date, the destructive extraction and analysis of drilling cores is the main possibility to obtain depth information about damaging water ingress in building floors. The time- and costintensive procedure constitutes an additional burden for building insurances that already list piped water damage as their largest item. With its high sensitivity for water, a ground-penetrating radar (GPR) could provide important support to approach this problem in a non-destructive way. In this research, we study the influence of moisture damage on GPR signals at different floor constructions. For this purpose, a modular specimen with interchangeable layers is developed to vary the screed and insulation material, as well as the respective layer thickness. The obtained data set is then used to investigate suitable signal features to classify three scenarios: dry, damaged insulation, and damaged screed. It was found that analyzing statistical distributions of A-scan features inside one B-scan allows for accurate classification on unknown floor constructions. Combining the features with multivariate data analysis and machine learning was the key to achieve satisfying results. The developed method provides a basis for upcoming validations on real damage cases. KW - Radar KW - Material Moisture KW - Non-destructive testing KW - Signal Features KW - Civil Engineering KW - Machine Learning PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533606 DO - https://doi.org/10.3390/app11198820 VL - 11 IS - 19 SP - 8820 PB - MDPI AN - OPUS4-53360 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weise, Frank A1 - von Werder, Julia A1 - Manninger, Tanja A1 - Maier, Bärbel A1 - Fladt, Matthias A1 - Simon, Sebastian A1 - Gardei, Andre A1 - Höhnel, Desirée A1 - Pirskawetz, Stephan A1 - Meng, Birgit T1 - A multiscale and multimethod approach to assess and mitigate concrete damage due to alkali-silica reaction N2 - Alkali-silica reaction (ASR) is a chemical reaction within concrete which can lead over time to cracking and spalling. Due to the complexity of the problem, it still causes damage to concrete constructions worldwide. The publication aims to illustrate the interdisciplinary research of the German Federal Institute for Materials Research and Testing (BAM) within the last 20 years, considering all aspects of ASR topics from the macro to the micro level. First, methods for characterization and assessment of ASR risks and reaction products used at BAM are explained and classified in the international context. Subsequently the added value of the research approach by combining different, preferably nondestructive, methods across all scales is explained using specific examples from a variety of research projects. Aspects covered range from the development of new test-setups to assess aggregate reactivity, to analysis of microstructure and reaction products using microscopical, spectroscopical and X-ray methods, to the development of a testing methodology for existing concrete pavements including in-depth analysis of the visual damage indicator and the de-icing salt input using innovative testing techniques. Finally, research regarding a novel avoidance strategy that makes use of internal hydrophobization of the concrete mix is presented. KW - Mitigation strategies KW - Concrete KW - Damage analysis KW - Alkali silica reaction KW - Road pavement KW - Accelerated testing KW - Non-destructive testing KW - Microstructure PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:101:1-2022052515100075090235 DO - https://doi.org/10.1002/adem.202101346 SN - 1527-2648 VL - 24 IS - 6 SP - 1 EP - 36 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritzsche, Sven A1 - Jaenisch, Gerd-Rüdiger A1 - Pavasaryte, Lina A1 - Funk, Alexander T1 - XCT and DLW: Synergies of Two Techniques at Sub-Micrometer Resolution N2 - Direct Laser Writing (DLW) and X-ray computed tomography (XCT) both offer unique possibilities in their respective fields. DLW produces full three-dimensional (3D) polymer structures on the microscale with resolutions below 100 nm. The fabricated structures can be analysed by XCT or X-ray microscopy (XRM), which incorporates additional X-ray lenses, in three dimensions down to a minimal basic spatial resolution of about 500 nm or 50 nm, respectively. In this work, two different DLW structures are analysed via XCT. Internal defects are detected and analysed for the purpose of quality control. Defects and structures with sizes down to 1.5 µm are successfully analysed. A 3D reconstruction and internal, hidden features of the fabricated structures are shown and discussed. In a first-of-its-kind study, we demonstrate the detectability of a single-voxel line inside a fabricated structure that would not be detectable with SEM or light microscopy. Furthermore, the direct fabrication on a PET substrate is shown to overcome the high X-ray absorbance of commonly used glass substrates. Attenuation spectra of SZ2080 and glass substrates are compared to a fabrication route direct on a 170 µm PET foil. The practical aspects of XCT measurements for DLW structures on different substrates will be discussed. KW - Non-destructive testing KW - Two-photon polymerization KW - X-ray microscopy KW - XCT KW - 2PP KW - Direct laser writing PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560525 DO - https://doi.org/10.3390/app122010488 VL - 12 IS - 20 SP - 1 EP - 15 PB - MDPI CY - Basel AN - OPUS4-56052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Bartolac, M. A1 - Bien, J. A1 - Górski, M. A1 - Keßler, S. A1 - Küttenbaum, Stefan A1 - Kuzawa, M. A1 - Ley, J. A1 - Maack, Stefan A1 - Mendler, A. A1 - Ryjáček, P. A1 - Santos, L. A1 - Verstrynge, E. ED - Keßler, S. ED - Limongelli, M. P. ED - Apostolidi, E. T1 - Chapter 2: Condition survey - Testing and monitoring methods N2 - The through-life management of our constantly ageing infrastructure is a basic requirement in order to ensure their structural safety and serviceability. Each structure experiences deterioration processes with time leading to a decrease of structural safety and serviceability. The design of new structures considers the expected deterioration for a defined period, the design service life. However, a frequent survey of structural safety controlling structural condition should be mandatory and a maintenance plan should be an integral part of the design. In addition, many structures have exceeded their design service life already or are very close to it leading to an increasing demand for condition assessment. On the one hand, assumptions made during design are not valid any more due to change of the loads, e.g., increasing traffic loads in terms of number and weights. On the other hand, design codes evolved over time in such a way that existing structures do not comply with today’s standards. In all these cases, the through-life management is an important tool to maintain the accessibility of existing structures with known reliability. In line with the new Model Code for Concrete Structures, which includes guidance for both – design of new structures and assessment of existing structures, the Task Group 3.3 focused on the compilation of a state-of-the-art guideline for the through-life management of existing concrete structures, including: Data acquisition by testing and monitoring techniques; Condition assessment for the evaluation of existing structures; Performance prediction using advanced methods; Decision-making procedures to perform a complete assessment of existing structure. The overall objective of the through-life management is the assessment of the current condition and the estimation of the remaining service life under consideration of all boundary conditions. KW - Life management KW - Concrete KW - Non-destructive testing KW - Structural health monitoring KW - State-of-the-art PY - 2023 UR - https://doi.org/10.35789/fib.BULL.0109 SN - 978-2-88394-172-4 DO - https://doi.org/10.35789/fib.BULL.0109.Ch02 SN - 1562-3610 VL - fib Bulletin 109 SP - 16 EP - 38 PB - Fédération internationale du béton (fib) CY - Lausanne AN - OPUS4-59110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Helmerich, Rosemarie A1 - Milmann, Boris A1 - Wöstmann, Jens T1 - Bond durability of CFRP-laminates on concrete bridges N2 - Trans-European corridors for transport of people and goods require strengthening of bridges to carry increased axle loads in terms of absolute axle loads and of their frequency. Most of the bridges along highways are reinforced or prestressed concrete bridges. Since the late 1990s, CFRP laminates have been applied to box girder and T-beam bridges to increase the overall capacity. Although regular inspections are carried out, no special method was available to test the bond condition of CFRP laminates after being in Service for more than ten years. The German Center of Competence in Civil Engineering is aware of this need and funded a research project to investigate the bond condition by means of advanced non-destructive testing (NDT). T2 - 31st Danubia-Adria Symposium on advances in experimental mechanics CY - Kempten, Germany DA - 24.09.2014 KW - Concrete bridges KW - Strengthening KW - Non-destructive testing KW - CFRP KW - Durability KW - Inspection PY - 2014 SN - 978-3-00-046740-0 SP - 1 EP - 2 AN - OPUS4-33116 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, Martin A1 - Dackermann, U. A1 - Li, J. T1 - Elastic wave modes for the assessment of structural timber: ultrasonic echo for building elements and guided waves for pole and pile structures N2 - This paper presents the state-of-the-art of using non-destructive testing (NDT) methods based on elastic waves for the condition assessment of structural timber. Two very promising approaches based on the propagation and reflections of elastic waves are described. While the first approach uses ultrasonic echoes for the testing of wooden building elements, the second approach uses guided waves (GW) for the testing of timber pole and pile structures. The basic principle behind both approaches is that elastic waves induced in a timber structure will propagate through its material until they encounter a change in stiffness, cross-sectional area or density, at which point they will reflect back. By measuring the wave echoes, it is possible to determine geometric properties of the tested structures such as the back wall of timber elements or the underground length of timber poles or piles. In addition, the internal state of the tested structures can be assessed since damage and defects such as rot, fungi or termite attacks will cause early reflections of the elastic waves as well as it can result in changes in wave velocity, wave attenuation and wave mode conversion. In the paper, the principles and theory of using elastic wave propagation for the assessment of wooden building elements and timber pole/pile structures are described. The state-of-the-art in testing equipment and procedures is presented and detailed examples are given on the practical application of both testing approaches. Recent encouraging developments of cutting edge research are presented along with challenges for future research. KW - Elastic wave KW - Ultrasonic echo KW - SAFT (synthetic aperture focusing technique) KW - Guided wave KW - Timber structure KW - Timber pole KW - Impulse response KW - Condition assessment KW - Timber KW - Non-destructive testing KW - Ultrasouind PY - 2014 DO - https://doi.org/10.1007/s13349-014-0087-2 SN - 2190-5452 SN - 2190-5479 VL - 5 IS - 2 SP - 221 EP - 249 PB - Springer CY - Berlin; Heidelberg AN - OPUS4-31867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Helmerich, Rosemarie A1 - Milmann, Boris A1 - Wöstmann, Jens T1 - Non-destructive detection of surface-bond defects in carbon composite-strengthened concrete structures N2 - For almost 15 years, carbon fibre-reinforced polymer (CFRP) plates and sheets have been used for strengthening and repair of civil engineering structures. CFRP plates were applied to upgrade structures for change in use or increasing traffic load. CFRP laminates have also been used to repair deteriorated structures such as multi-storey parking or bridges. The execution quality and condition of the strengthening measure in terms of bond integrity were neither monitored nor tested systematically. Inspectors eventually applied simple hammer knocking during regular main inspection for subjective noise distinction as a measure for eventual insufficient bond. This paper presents the feasibility and the limitations of low-frequency transversal ultrasonic waves with dry-coupling point-contact sensors for inspection and defect detection between CFRP laminate and concrete surfaces. The German Centre of Competence in Civil Engineering (DIBt) has initiated a national research project [Helmerich et al. (2012). Condition analysis of bonded CFRP-applications on concrete structures by means of non-destructive testing [in German: Zustandsuntersuchung von CFK-Klebeverstärkungen an Betonbauteilen mittels zerstörungsfreier Prüfung (ZfP)]. Final, internal project report], carried out at the Federal Institute for Materials Research and Testing (BAM), Germany. The aim of the project was to present a potential non-destructive testing method for bond defect detection as a measure for the durability of the strengthening system more than 10 years after application. KW - Concrete bridges KW - Strengthening KW - Non-destructive testing KW - Composite materials KW - Durability KW - Inspection PY - 2015 DO - https://doi.org/10.1080/15732479.2013.879322 SN - 1573-2479 VL - 11 IS - 1 SP - 3 EP - 14 PB - Taylor & Francis CY - London [u.a.] AN - OPUS4-33086 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pelkner, Matthias A1 - Reimund, Verena A1 - Erthner, Thomas A1 - Kreutzbruck, Marc T1 - Size adapted GMR arrays for the automated inspection of surface breaking cracks in roller bearings N2 - Their small size together with a remarkable field sensitivity are the most prominent features of present-day GMR sensors paving the way for various applications in automated non-destructive testing (NDT). This work presents a prototype for fast and automated magnetic testing of roller bearings. A local magnetization unit excites the magnetic field inside the bearing. As a result of a design study and the following wafer fabrication the probe was equipped with NDT-adapted GMR sensor arrays in which 48 elements measures the field response. The detection of artificial and 40 µm deep defects could be resolved with a SNR better than 20 dB. In addition, we report of first results of a POD (Probability of Detection) analysis using GMR sensors to investigate bearings with EDM (electronic discharge machining) notches having depths down to 10 µm. Finally, we estimate successfully the depth of a 57 µm notch from the measured data. KW - Giant magneto resistance KW - Non-destructive testing KW - Magnetic flux leakage KW - Sensor array PY - 2014 DO - https://doi.org/10.3233/JAE-141866 SN - 1383-5416 SN - 0925-2096 VL - 45 IS - 1-4 SP - 473 EP - 479 PB - IOS Press CY - Amsterdam, The Netherlands AN - OPUS4-31278 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pelkner, Matthias A1 - Reimund, Verena A1 - Erthner, Thomas A1 - Panke, Nicolai A1 - Kreutzbruck, Marc ED - Chimenti, D.E. ED - Bond, L.J. ED - Thompson, D.O. T1 - Automated inspection of surface breaking cracks using GMR sensor arrays N2 - We present a prototype for automated magnetic stray field testing of ferromagnetic roller bearings. For this purpose NDE-adapted GMR sensor arrays (giant magneto resistance) are used for the detection of surface breaking cracks. The sensors are miniaturized down to the lower µm-regime to achieve adequate spatial resolution. In doing so, sensor arrays with up to 48 elements are used to inspect the bearing surface within a few seconds only. In contrast to magnetic particle inspection (MPI), where the global magnetization requires a further inspection step and succeeding demagnetization, the presented prototype only locally magnetize the surface area in the vicinity of the GMR Sensors. For the local magnetization, the applied sub-surface magnetic field was simulated and proofed for detecting flaws with a depth of a few 10 µm. By multiplexing the sensor array with an adapted read out electronics we quasi simultaneously detect the normal field component of about 100µm above the surface. The detection of artificial notches with a depth of 40 µm and more could be resolved with a SNR better than 20 dB. The presented testing facility is fast and provides a step towards automated testing of safety relevant steel components. T2 - 40th Annual review of progress in quantitative nondestructive evaluation CY - Baltimore, Maryland, USA DA - 21.07.2013 KW - GMR KW - Magnetic flux leakage KW - Sensor array KW - Non-destructive testing PY - 2014 SN - 978-0-7354-1212-5 SN - 978-0-7354-1211-8 DO - https://doi.org/10.1063/1.4864984 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 1581 33B SP - 1393 EP - 1399 PB - AIP Publishing AN - OPUS4-31280 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Myrach, Philipp A1 - Jonietz, Florian A1 - Meinel, Dietmar A1 - Suwala, Hubert A1 - Ziegler, Mathias T1 - Calibration of thermographic spot weld testing with X-ray computed tomography N2 - The paper presents an attempt for the calibration of an active thermography method that is suitable for the non-destructive evaluation of spot welds. Nowadays, the quality of spot welds is commonly characterised by the application of random chisel tests, which are time consuming, expensive and destructive. Recently a non-destructive testing method by means of active thermography was proposed that relies on the fact that the mechanical connection formed by the spot weld also serves as a thermal bridge between the two steel sheets joined in the welding process. It is shown in this paper that this thermal bridge can be thermographically characterised by extracting a measure for the spot weld diameter and hence the quality of the spot weld. The determination of the absolute value of the diameter hereby relies on a calibration of the testing system, which is performed by means of X-ray computed tomography in this study. The experiments were carried out using different experimental approaches, namely transmission as well as reflection geometry wSetup in reflectionith laser illumination. A comprehensive evaluation of samples produced using different welding currents, hence different quality, was carried out in order to validate the thermographic results. KW - Thermography KW - Spot welds KW - Spot welding KW - Computed thomography KW - Non-destructive testing PY - 2017 DO - https://doi.org/10.1080/17686733.2017.1281554 SN - 1768-6733 SN - 2116-7176 VL - 14 IS - 1 SP - 122 EP - 131 PB - Taylor & Francis CY - London AN - OPUS4-40180 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lenke, Karoline A1 - Trappe, Volker T1 - Short fibre polymide under combined shear and tensile loading: a non-destructive evaluation of micro damage evolution N2 - The following paper focuses on the evolution of micro damage in short fibre reinforced polyamide. Therefore, tube samples are subjected to uni- and biaxial fatigue loadings. The evolution of micro damage is analysed by the non-destructive method of X-ray refraction analysis with consideration of the fibre orientation distribution. For validation of the applied micro damage models, fractographic analyses are performed. Concluding some general results, it has been observed that the load ratio influences the quantitative dominance of micro damage, whereas occuring damage phenomena depend on the type of loading (i.e. tension and torsion). Thus, zones in the Haigh-diagram are detected, where the occurence of damage mechanisms qualitatively and quantitatively changes. This is a basis for further research regarding anisotropic damage criteria. T2 - ICCM20 - 20th International conference on composite materials CY - Copenhagen, Denmark DA - 2015-07-19 KW - Short fibre composites KW - Fatigue KW - Damage evolution KW - Biaxial loading KW - Non-destructive testing PY - 2015 SN - 978-1629931999 SP - 1 EP - 10(?) AN - OPUS4-33799 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Röllig, Mathias A1 - Steinfurth, Henrik A1 - Meinhardt, J. A1 - Arnold, T. T1 - Untersuchung sicherheitsrelevanter Ablösungen von Fassadenelementen mit aktiver Thermografie N2 - Die Bewertung des Zustandes und der Haftung von Putz und Fassadenelementen auf den darunterliegenden Bauwerksstrukturen ist eine häufig auftretende Fragestellung bei der Erhaltung und Instandsetzung von Bauwerken und Baudenkmälern. Hier müssen nicht nur wirtschaftliche und denkmalpflegerische, sondern auch sicherheitsrelevante Aspekte berücksichtigt werden. Fehlstellen und Ablösungen können, auch wiederholend, mit hoher Nachweisempfindlichkeit mit aktiven Thermografieverfahren geortet und unter bestimmten Voraussetzungen quantitativ bewertet werden. Dazu wird der zu untersuchende Bereich zunächst kurzzeitig (mehrere Minuten lang) erwärmt und anschließend die Abkühlung mit einer Infrarotkamera aufgezeichnet. Systematische Untersuchungen an Probekörpern mit einer Vielzahl unterschiedlicher Fehlstellen unterhalb von Kalkputz, Fliesen und Klinkerriemchen zeigen, dass die Fehlstellen sowohl mittels künstlicher Erwärmung durch einen Infrarotstrahler als auch mittels natürlicher Erwärmung durch die Sonne detektiert und charakterisiert werden können. --------------------------------------------------------------------------------------------------------------------------------------- The evaluation of condition and adhesion of plaster and façade elements to the underlying building structure is a common issue in the maintenance and repair of buildings and monuments. Here not only economic and preservation, but also safety relevant aspects have to be considered. Voids and delaminations can be detected repeatedly with high sensitivity using active thermography methods. Under certain conditions, also a quantitative evaluation is possible. The area under investigation has to be heated up for a short time (up to several minutes). Subsequently, the cooling down is recorded using an infrared camera. Systematic studies on test specimens with a variety of defects below lime plaster, tiles and brick tiles show that the defects can be detected and even characterized both by means of artificial heating using an infrared heater, as well as by natural solar heating. KW - Zerstörungsfreie Prüfung KW - Aktive Thermografie KW - Sonnenerwärmung KW - Fassade KW - Putz KW - Klinkerriemchen KW - Fliese KW - Fehlstelle KW - Ablösung KW - Non-destructive testing KW - Active thermography KW - Heating using solar radiation KW - Facade KW - Plaster KW - Brick tile KW - Tile KW - Void KW - Delamination KW - Bauwerkserhaltung/Sanierung KW - Maintenance and Repair KW - Neue Verfahren/Versuchstechnik KW - New Processes/Experimental Techniques KW - Qualitätssicherung KW - Quality assurement PY - 2015 DO - https://doi.org/10.1002/bate.201500050 SN - 0932-8351 SN - 1437-0999 SN - 0005-6820 SN - 0341-1052 SN - 0932-6359 VL - 92 IS - 10 SP - 1 EP - 6 PB - Ernst & Sohn CY - Berlin AN - OPUS4-34527 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Pelkner, Matthias A1 - Kreutzbruck, Marc ED - Fermon, C. ED - Van de Voorde, M. H. T1 - Spin Electronics for Non Destructive Testing N2 - Electromagnetic methods are widely used in Non-destructive Testing industries (NDT). In order to meet the requirements, safety-relevant products and structures have to be tested reliably during production or within subsequent maintenance cycles. For this purpose industrial users call for adapted testing methods which allow the detection of relevant defects such as cracks and pore in ferromagnetic or conductive materials. Automated testing systems and the application of sensor arrays are of great interest in order to enhance inspection quality and to decrease testing time and costs. Magneto resistance (MR) sensors like giant magneto resistance (GMR) or tunnel magneto resistance sensor (TMR) have proofed their suitability in many NDT-applications due to their extraordinary properties which combine high field sensitivity, a high spatial resolution and low costs. Due to their small size these sensors can be useful – in addition to the pure detection task – for a more detailed defect characterization and defect reconstruction providing defect size, orientation and geometry. This chapter gives a brief introduction of electromagnetic testing methods, i.e., magnetic particle inspection (MPI) and eddy current testing (ET), followed by two different approaches for which MR sensor arrays were successfully adapted. KW - Magneto resistance KW - GMR KW - TMR KW - Non-destructive testing KW - Magnetic flux leakage KW - Eddy current PY - 2017 SN - 978-3-527-33985-3 SP - 81 EP - 102 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-41463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane A1 - Wöstmann, Jens A1 - Trela, Christiane A1 - Röllig, Mathias ED - L. Binda, ED - M. di Prisco, ED - R. Felicetti, T1 - Investigation of moisture content and distribution with radar and active thermography T2 - 1st International RILEM Conference, on Site Assessment of Concrete, Masonry and Timber Structures (SACoMaTiS 2008) CY - Varenna, Italy DA - 2008-09-01 KW - Radar KW - Active thermography KW - Non-destructive testing KW - Moisture KW - Masonry PY - 2008 SN - 978-2-35158-062-2 VL - 1 IS - PRO 59 SP - 411 EP - 420 PB - RILEM Publications AN - OPUS4-18032 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Paasche, H. A1 - Wendrich, Astrid A1 - Tronicke, J. A1 - Trela, Christiane T1 - Detecting voids in masonry by cooperatively inverting P-wave and georadar traveltimes N2 - Collecting different geophysical data sets at the same object and site offers the opportunity to reduce uncertainties and ambiguities in data analysis and interpretation. To be effective, the different available data sets should be linked during the model-generation process, e.g. by cooperative inversion. In this study, we apply a recently developed zonal cooperative inversion approach based on fuzzy c-means cluster analysis to a non-destructive testing experiment. After briefly reviewing the fundamentals of the inversion strategy, we present a synthetic study investigating the potential of the method to detect air-filled voids in masonry by using ultrasonic and georadar traveltime data. Then, we present and discuss laboratory experiments including the results of cooperatively inverted ultrasonic and georadar traveltimes collected at a masonry test specimen. The geometry of the specimen is known and is thus an ideal test object for a first-time real application of the novel zonal cooperative inversion procedure. Compared to the results of separate inversions of ultrasonic and georadar traveltimes, the zonal cooperative inversion allows for an improved delineation of the size and position of the cavities. The P-wave and georadar velocities determined for the model regions corresponding to the cavities are also improved. KW - Non-destructive testing KW - Tomography KW - Traveltime KW - Cooperative inversion KW - Cluster analysis PY - 2008 DO - https://doi.org/10.1088/1742-2132/5/3/002 SN - 1742-2132 VL - 5 SP - 256 EP - 267 PB - IOP Publ. CY - Bristol AN - OPUS4-18815 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane A1 - Wöstmann, Jens A1 - Milmann, Boris A1 - Hennen, C. ED - Karl-Eugen Kurrer, ED - Lorenz, Werner ED - Volker Wetzk, T1 - Structural assessment of stone walls of St. Servatius church in Quedlinburg N2 - Non-destructive and minor destructive testing methods enable a classification of historic structures, building processes, applied building technologies and materials. Therefore, these methods should be part of the global investigation of historic buildings which is usually required before the planning of any building intervention. The case study presented herein encompasses experimental work carried out at the St. Servatius Church in Quedlinburg, Germany. Within a comprehensive restoration campaign, non-destructive on-site investigations were carried out with radar and ultrasonics. The results were combined with plans, views and cores recorded in advance. T2 - 3rd International congress on construction history CY - Cottbus, Germany DA - 2009-05-20 KW - Non-destructive testing KW - Radar KW - Ultrasonic KW - Stone KW - Masonry PY - 2009 SN - 978-3-936033-31-1 VL - 2 SP - 983 EP - 990 PB - NEUNPLUS1 - Verlag und Service GmbH AN - OPUS4-19741 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane A1 - Wöstmann, Jens A1 - Röllig, Mathias A1 - Köpp, Christian A1 - Borchardt, Kerstin ED - Mateja Golez, T1 - Non-destructive testing of walls and ground of the Carthusian monastery at Zice KW - Non-destructive testing KW - Active thermography KW - Radar KW - Brick KW - Stone KW - Masonry PY - 2009 SN - 978-961-90366-4-8 SP - 101 EP - 117 CY - Ljubljana, Slovenia AN - OPUS4-19742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Maierhofer, Christiane A1 - Röllig, Mathias T1 - Application of active thermography to the detection of safety relevant defects in civil engineering structures T2 - IRS² 2009 - 11th International conference on infrared sensors & systems CY - Nürnberg, Germany DA - 2009-05-26 KW - Non-destructive testing KW - Active thermography KW - Pulse-phase thermography KW - Concrete KW - Voids KW - Cracks KW - CFRP delaminations PY - 2009 SN - 978-3-9810993-6-2 IS - Chapter 2.2 SP - 215 EP - 220 AN - OPUS4-19873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Köpp, Christian A1 - Hamann, M. A1 - Hennen, C. A1 - Binda, L. A1 - Saisi, A. A1 - Zanzi, L. T1 - Non-destructive investigation of structural elements of the "Altes Museum" in Berlin N2 - Strategies and methodologies for the assessment of historic masonry structures based on non-destructive and minor-destructive testing methods were developed in the European Research Project ONSITEFORMASONRY and were successfully applied to assess the structure and material properties of selected structural elements in the Altes Museum in Berlin-Mitte. For the planning of a broad reconstruction within the framework of a master plan concerning the whole of Museum Island in Berlin, several questions arose which are also typical for other historic structures in general, thus the Altes Museum was chosen as a pilot site for the validation of non-destructive testing methods. KW - Non-destructive testing KW - Historic masonry KW - Radar KW - Columns KW - Cupola KW - Anchors PY - 2008 SN - 978-1-84564-106-1 DO - https://doi.org/10.2495/HPSM080521 SN - 1746-4498 SN - 1743-3509 VL - 97 SP - 513 EP - 522 PB - WIT Press CY - Southampton [u.a.] AN - OPUS4-17890 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, Martin A1 - Milmann, Boris A1 - Mielentz, Frank A1 - Streicher, Doreen A1 - Redmer, Bernhard A1 - Mayer, K. A1 - Langenberg, K.-J. A1 - Schickert, M. T1 - Ultrasonic Imaging Methods for Investigation of Post-tensioned Concrete Structures: A Study of Interfaces at Artificial Grouting Faults and Its Verification N2 - This paper presents the progress of successful location of grouting faults in tendon ducts with ultrasonic imaging. The examples were obtained in the research group FOR 384 funded by DFG (German Research Foundation). The co-operation of experimental research and modeling allowed imaging and identification of grouted and ungrouted areas of tendon ducts (including strands) in a large test specimen (40 m²). In addition to the criteria for indicating grouting faults in post-tensioned ducts known until now the phase evaluation of reflected ultrasonic pulses is described. Experiments and modeling of wave propagation are presented for reflections at metal plates in concrete (thickness range 0.5 mm to 40 mm) and for tendon ducts including strands. The main part of the progress was achieved by automated measurements using dry contact transducers, 3D-SAFT reconstruction including phase evaluation and modeling considering wave propagation for typical elastic parameters and exact experimental site conditions. The results for shear waves as well as for pressure waves are compared in the frequency range from 50 kHz to 120 kHz. KW - Non-destructive testing KW - Tendons KW - Prestressed concrete bridges KW - Ultrasonic echo KW - Reconstruction calculation KW - 3D-SAFT KW - Modeling (EFIT) PY - 2008 DO - https://doi.org/10.1007/s10921-008-0033-5 SN - 0195-9298 SN - 1573-4862 VL - 27 IS - 1-3 SP - 67 EP - 82 PB - Plenum Press CY - New York, NY AN - OPUS4-17922 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beutel, R. A1 - Reinhardt, H.-W. A1 - Grosse, C.U. A1 - Glaubitt, A. A1 - Krause, Martin A1 - Maierhofer, Christiane A1 - Algernon, Daniel A1 - Wiggenhauser, Herbert A1 - Schickert, M. T1 - Comparative performance tests and validation of NDT methods for concrete testing N2 - Validation of non-destructive testing methods is necessary to create a common basis where different systems can be compared and their applications and limitations be identified. This can be achieved through comparing the measurements taken by several systems used for a common diagnostic purpose under practical but controlled testing conditions. Well-designed small and large laboratory or field specimens promise such conditions. The special concrete specimen (LCS) at BAM was constructed for validation purposes, in particular, to be used for evaluating the performance of echo methods. The thickness of the specimen is varying and it contains carefully designed built-in faults, such as voids, honeycombs and tendon ducts with various degrees of grouting defects. Since the geometry and condition of the defects are known, it can be used to compare the performance of radar, ultrasonic, impact-echo. The research was conducted within the Research group FOR384, sponsored by the German Research Society DFG. KW - Performance demonstration KW - Non-destructive testing KW - Concrete KW - Radar KW - Ultrasound KW - Impact-echo PY - 2008 DO - https://doi.org/10.1007/s10921-008-0037-1 SN - 0195-9298 SN - 1573-4862 VL - 27 IS - 1-3 SP - 59 EP - 65 PB - Plenum Press CY - New York, NY AN - OPUS4-17925 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane A1 - Köpp, Christian A1 - Kruschwitz, Sabine A1 - Drdacky, M. A1 - Hennen, C. A1 - Lanza, S. A1 - Tomazevic, M. A1 - Kolymbas, D. A1 - Herle, I. A1 - Virsta, A. A1 - Binda, L. A1 - Askew, P. ED - Dina D´Ayala, ED - Enrico Fodde, T1 - Cultural Heritage protection against flood - A European FP6 research project T2 - 6th International Conference on Structural Analysis of Historic Construction (SAHC), "Structural Analysis of Historic Construction - Preserving Safety and Significance" CY - Bath, UK DA - 2008-07-02 KW - Cultural heritage KW - Flood KW - Damage KW - Non-destructive testing PY - 2008 SN - 978-0-415-46872-5 SP - 109 EP - 117 PB - CRC Press AN - OPUS4-17907 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane ED - L. Binda, ED - M. di Prisco, ED - R. Felicetti, T1 - Combination of non-destructive testing methods for the assessment of masonry structures T2 - 1st International RILEM Conference, "on Site Assessment of Concrete, Masonry and Timber Structures" (SACoMaTiS 2008) CY - Varenna, Italy DA - 2008-09-01 KW - Non-destructive testing KW - Masonry KW - Structure KW - Moisture KW - Combination of methods KW - Strategies PY - 2008 SN - 978-2-35158-062-2 VL - 1 IS - PRO 59 SP - 715 EP - 726 PB - RILEM Publications AN - OPUS4-18956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Oliver A1 - Bretz, Simone A1 - Hagnau, Carola A1 - Ranz, Hans-Jörg A1 - Wolff, Timo T1 - Pigments, dyes, and black enamel - the colorants of reverse paintings on glass N2 - Nondestructive analyses of medieval reverse paintings on glass revealed the same dyes and pigments customarily used in panel paintings. However, there is one exception: the black colorant is not a carbon-based pigment, but black enamel. In this respect, the stylistic as well as the technical influence of stained glass artwork can clearly be seen on reverse paintings on glass. However, there is a crucial difference: in reverse paintings, the black enamel is not fired onto the glass but painted (cold painting). Additional analyses confirmed these findings. Based on these results, the art form "reverse painting on glass" has technically to be characterized as a mixture of "stained glass" and "panel painting" that nonetheless develops into a genre of its own. KW - Archaeometry KW - Cultural heritage KW - Non-destructive testing PY - 2009 DO - https://doi.org/10.1007/s12520-009-0021-4 SN - 1866-9557 SN - 1866-9565 VL - 1 IS - 4 SP - 263 EP - 271 PB - Springer CY - Berlin ; Heidelberg AN - OPUS4-20877 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Maierhofer, Christiane A1 - Kohl, Christoph A1 - Wöstmann, Jens ED - Maierhofer, C. ED - Reinhardt, H.-W. ED - Dobmann, G. T1 - Combining the results of various non-destructive evaluation techniques for reinforced concrete: data fusion KW - Non-destructive testing KW - Concrete KW - Data fusion KW - Radar KW - Ultrasonic techniques PY - 2010 SN - 978-1-84569-950-5 VL - 2 IS - Chapter 5 SP - 95 EP - 107 PB - Woodhead Publ. AN - OPUS4-22607 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Maierhofer, Christiane ED - Maierhofer, C. ED - Reinhardt, H.-W. ED - Dobmann, G. T1 - Planning a non-destructive test programme for reinforced concrete structures KW - Non-destructive testing KW - Concrete KW - On-site assessment KW - Method validation KW - Quality assurance PY - 2010 SN - 978-1-84569-950-5 VL - 2 IS - Chapter 1 SP - 3 EP - 13 PB - Woodhead Publ. AN - OPUS4-22610 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hempel, M. A1 - Tomm, J.W. A1 - Ziegler, Mathias A1 - Elsaesser, T. A1 - Michel, N. A1 - Krakowski, M. T1 - Catastrophic optical damage at front and rear facets of diode lasers N2 - Single-pulse tests of the catastrophic optical damage (COD) are performed for three batches of diode lasers with different gain-regions. The tests involve in situ inspection of front, rear, and side of the devices by a thermocamera. Devices with an Al-containing gain-region show COD at the front facet, as expected for strong facet heating via surface recombination and reabsorption of laser light. In contrast, Al-free devices with low surface recombination rates tend to fail at the rear facet, pointing to a different heating scenario. The high carrier density at the rear facet favors heating and COD via Auger recombination processes. KW - Thermography KW - Catastrophic optical damage KW - High power diode lasers KW - Destructive testing KW - Non-destructive testing KW - Auger effect KW - Carrier density KW - Heating KW - Laser beam effects KW - Optical testing KW - Semiconductor lasers KW - Surface recombination PY - 2010 DO - https://doi.org/10.1063/1.3524235 SN - 0003-6951 SN - 1077-3118 VL - 97 IS - 23 SP - 231101-1 - 231101-3 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-22763 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tomm, J.W. A1 - Ziegler, Mathias A1 - Hempel, M. A1 - Elsaesser, T. T1 - Mechanisms and fast kinetics of the catastrophic optical damage (COD) in GaAs-based diode lasers N2 - COD diagram determined for a batch of broad-area AlGaAs diode lasers. The time to COD within a single current pulse is plotted versus the actual average optical power in the moment when the COD takes place. Full circles stand for clearly identified COD events (right ordinate), whereas open circles (left ordinate) represent the pulse duration in experiments, where no COD has been detected. A borderline (gray) exists between two regions, i. e., parameter sets, of presence (orange) and absence of COD (blue). This borderline is somewhat blurred because of the randomness in filamentation of the laser nearfield and scatter in properties of the involved individual devices. KW - Semiconductor laser KW - Thermography KW - Catastrophic optical damage KW - High-power diode lasers KW - Destructive testing KW - Non-destructive testing PY - 2011 DO - https://doi.org/10.1002/lpor.201000023 SN - 1863-8880 VL - 5 IS - 3 SP - 422 EP - 441 PB - Wiley-VCH CY - Weinheim AN - OPUS4-23624 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Binda, L. A1 - Maierhofer, Christiane ED - L. Binda, ED - M. Drdacky, ED - Kasal, B. T1 - Strategies for the assessment of historic masonry structures T2 - NSF/MSMT supported US-Czech project and RILEM Workshop - "In-Situ Evaluation of Historic Wood and Masonry Structures" CY - Prague, Czech Republic DA - 2006-07-10 KW - Non-destructive testing KW - Historic buildings KW - Masonry KW - Structure KW - Moisture KW - Combination of methods KW - Strategies PY - 2006 SN - 978-80-86246-36-9 SP - 86 EP - 104 AN - OPUS4-17889 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thomas, Hans-Martin A1 - Dey, Anika A1 - Heyder, R. T1 - Eddy current test method for early detection of rolling contact fatigue (RCF) in rails N2 - The findings indicate that rolling contact fatigue with consecutive head checks develops preferentially in rail sections that have experienced operational work-hardening. Such hardening can be identified by instruments measuring the increased hardness values with respect to the base material. Eddy current testing was initially introduced with the aim to detect head checks and determine their damage depth. Because the material texture influences eddy current flow in the test objects very strongly, variations in hardness can easily be visualised using this method. Thus, in principle, it is possible to predict places where head checks will emerge later. This knowledge may be very helpful in improving our understanding of head check emergence under real conditions. This knowledge may also help in developing new and effective precautionary maintenance strategies. KW - Rails KW - Rolling contact fatigue KW - Head checks KW - Non-destructive testing KW - Eddy current technique PY - 2010 DO - https://doi.org/10.1784/insi.2010.52.7.361 SN - 0007-1137 VL - 52 IS - 7 SP - 361 EP - 365 PB - British Institute of Non-Destructive Testing CY - Northampton AN - OPUS4-21934 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Dobmann, G. A1 - Kurz, J.H. A1 - Taffe, Alexander A1 - Streicher, Doreen ED - Maierhofer, C. ED - Reinhardt, H.-W. ED - Dobmann, G. T1 - Development of automated non-destructive evaluation (NDE) systems for reinforced concrete structures and other applications N2 - The introduction of an innovative process for non-destructive testing is described in terms of its different phases and how the process is controlled in the Fraunhofer IZFP in order to obtain optimal results. Examples are discussed of applications by IZFP in various important and safety-relevant industrial sectors where the automated inspection systems were introduced. These case studies include the inspection of railway components such as the wheel sets of the German high-speed train and in-line pipe inspection by using intelligent pipeline inspection gauges. Complex inspection systems, both hardware and software, developed in partnership with the Federal Institute for Materials Research and Inspection (BAM), were applied to inspection tasks in civil engineering. Two automated systems based on a robot and on a flexible manipulation are presented. Both systems can be applied to diverse inspection technologies and to the data fusion of various types of non-destructive testing (NDT) data. KW - Automated inspection systems KW - Non-destructive testing KW - Civil engineering KW - Robots KW - Data fusion KW - Railway components PY - 2010 SN - 978-1-84569-950-5 IS - Chapter 3 SP - 30 EP - 62 PB - Woodhead Publ. AN - OPUS4-23759 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Brink, Arne A1 - Röllig, Mathias A1 - Wiggenhauser, Herbert T1 - Quantitative Impulse-Thermography as Non-Destructive Testing Method in Civil Engineering - Experimental Results and Numerical Simulations N2 - Impulse-thermography is an active method for quantitative investigation of the near surface region of various structures which has recently been applied to civil engineering. It is well suited for the detection of voids and honeycombing in concrete up to concrete covers of 10 cm and more. For quantitative analysis, a computer program for numerical simulation of the heating up and cooling down processes was developed based on Finite Differences. With this program parameter studies have been performed for investigating the influence of environmental conditions, material parameters and geometry on the thermal behaviour. The comparison between experimental and simulated results enables the Inverse Solution. KW - Impulse-thermography KW - Numerical simulation KW - Non-destructive testing KW - Concrete KW - Civil engineering PY - 2005 SN - 0950-0618 VL - 19 IS - 10 SP - 731 EP - 737 PB - Elsevier CY - Oxford AN - OPUS4-3162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kohl, Christoph A1 - Krause, Martin A1 - Maierhofer, Christiane A1 - Mayer, K. A1 - Wöstmann, Jens A1 - Wiggenhauser, Herbert T1 - 3D-visualisation of NDT data using a data fusion technique KW - Non-destructive testing KW - Radar KW - Ultrasonic KW - Data fusion KW - SAFT PY - 2003 SN - 0007-1137 VL - 45 IS - 12 SP - 800 EP - 808 PB - British Institute of Non-Destructive Testing CY - Northampton AN - OPUS4-4585 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griepentrog, Michael A1 - Beck, Uwe ED - Schulte, J. ED - Niu, X. T1 - BAM certified reference materials for nano-metrology: Preparation, characterisation and certification T2 - 3rd Annual Conference of the Asia Pacific Nanotechnology Forum CY - Shanghai, China DA - 2004-12-09 KW - Certified reference materials KW - Film thickness KW - Mechanical properties KW - Surface acoustic waves KW - Naoindentation KW - Non-destructive testing KW - Destructive testing PY - 2005 SN - 0-97-57537-1-1 SP - 71 EP - 83 PB - Asia Pacific Nanotechnology Forum CY - Sydney AN - OPUS4-5482 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wilsch, Gerd A1 - Weritz, Friederike A1 - Schaurich, Dieter A1 - Wiggenhauser, Herbert T1 - Determination of chloride content in concrete structures with laser-induced breakdown spectroscopy N2 - An important criterion for the evaluation of reinforced concrete structures is the measurement of the chloride content. This will normally be done by time consuming standard chemical methods. We propose the application of a spectroscopic technique, the laser-induced breakdown spectroscopy (LIBS), which provides the advantages of a fast measurement, the potential for on-site application and the possibility to investigate a wide range of different measuring points. The surface can be scanned, or depth profiles are available from cores. Measurements can be performed directly on the sample surface and the results are available in near real time. We present LIBS results measured on concrete cores as well as on grinded and pressed material in comparison with the results of standard chemical methods. The optimum LIBS set-up and the experimental conditions to detect and measure chlorine in building materials are reported. The limits of detection were determined and calibration curves were measured. KW - Chloride content KW - Reinforced concrete KW - Laser-induced breakdown spectroscopy KW - Near real time results KW - Non-destructive testing PY - 2005 DO - https://doi.org/10.1016/j.conbuildmat.2005.06.001 SN - 0950-0618 VL - 19 IS - 10 SP - 724 EP - 730 PB - Elsevier CY - Oxford AN - OPUS4-10830 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane A1 - Hamann, M. A1 - Hennen, C. A1 - Knupfer, B. A1 - Marchisio, M. A1 - da Porto, F. A1 - Binda, L. A1 - Zanzi, L. T1 - Structural evaluation of historic walls and columns in the Altes Museum in Berlin using non-destructive testing methods T2 - Structural Analysis of Historical Constructions / 4th International Seminar on Structural Analysis of Historical Constructions, November 10-13, 2004, Padova, Italy (Proceedings) CY - Padova, Italy DA - 2004-11-10 KW - Non-destructive testing KW - Historic masonry KW - Case studies KW - Structural modelling PY - 2004 SN - 04-1536-379-9 SP - 331 EP - 341 PB - Taylor & Francis CY - London AN - OPUS4-4910 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane A1 - Köpp, Christian A1 - Wendrich, Astrid T1 - On-site investigation techniques for the structural evaluation of historic masonry buildings - a European research project T2 - Structural Analysis of Historical Constructions / 4th International Seminar on Structural Analysis of Historical Constructions CY - Padova, Italy DA - 2004-11-10 KW - Non-destructive testing KW - Historic masonry KW - Case studies KW - Structural modelling PY - 2004 SN - 04-1536-379-9 SP - 313 EP - 320 PB - Taylor & Francis CY - London AN - OPUS4-4979 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Wiggenhauser, Herbert A1 - Brink, Arne A1 - Röllig, Mathias T1 - Quantitative numerical analysis of transient IR-experiments on buildings N2 - Impulse-thermography has been established as a fast and reliable tool in many areas of non-destructive testing. In recent years several investigations have been done to apply active thermography to civil engineering. For quantitative investigations in this area of application, finite difference calculations have been performed for systematic studies on the influence of environmental conditions, heating power and time, defect depth and size and thermal properties of the bulk material (concrete). The comparison of simulated and experimental data enables the quantitative analysis of defects. T2 - 7th International Workshop on Advanced Infrared Technology and Applications ; 7th AITA Conference CY - Pisa, Italy DA - 2003-09-09 KW - Impulse-thermography KW - Numerical simulation KW - Non-destructive testing KW - Concrete KW - Civil engineering PY - 2004 DO - https://doi.org/10.1016/j.infrared.2004.03.022 SN - 1350-4495 VL - 46 IS - 1-2 SP - 173 EP - 180 PB - Pergamon Press CY - Oxford AN - OPUS4-4984 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Wendrich, Astrid A1 - Maierhofer, Christiane A1 - Kuritz, Matthias A1 - Köpp, Christian T1 - Aufbau eines historischen Mauerwerkskörpers ("Obelix") zur Bewertung von zerstörungsfreien Verfahren N2 - Zusammenfassung Auf dem Gelände der BAM entstand im Frühjahr 2003 ein Probekörper, der die Verbindung bildet zwischen Laborprüfkörpern und realen Bauwerken aus Mauerwerk. Er dient der Validierung und Weiterentwicklung von zerstörungsfreien Prüfverfahren zur Untersuchung von historischem Mauerwerk. Dabei wurde große Sorgfalt auf die Materialauswahl und den strukturellen Aufbau gelegt. Die Materialien sollten denen von realen, historischen Bauwerken entsprechen. Der strukturelle Aufbau ergibt sich aus praxisrelevanten Fragestellungen. Der Probekörper steht auch anderen Arbeitsgruppen für Verfahrensvalidierungen zur Verfügung. T2 - Jahrestagung Zerstörungsfreie Materialprüfung 2004 CY - Salzburg, Österreich DA - 2004-05-17 KW - Historic masonry KW - Test specimen KW - Validation KW - Non-destructive testing PY - 2004 UR - http://www.ndt.net/article/dgzfp04/papers/p40/p40.htm SN - 3-931381-55-2 SP - 1 EP - 11(?) PB - DGZfP CY - Berlin AN - OPUS4-5199 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Brink, Arne A1 - Röllig, Mathias A1 - Wiggenhauser, Herbert T1 - Detection of shallow voids in concrete structures with impulse thermography and radar N2 - New thermography systems enable the application of active investigation techniques, i.e. the observation of the cooling down process after heating the surface of a structure under investigation. Defects like voids in concrete having a different thermal diffusivity in comparison to the bulk material are visualised by different surface temperatures. The differences between temperature transient curves above sound regions and above inhomogeneities are expected to include information about the defect parameters. Experimental investigations with impulse thermography and radar on a concrete test specimen containing voids were analysed. Radar was used to determine the depth of the voids. The influence of size and depth of the voids on the temperature transient curves was studied for different heating times. The transient curves were also fitted with a simple semi-empirical model. KW - Impulse thermography KW - Radar KW - Non-destructive testing KW - Concrete KW - Civil engineering PY - 2003 SN - 0963-8695 VL - 36 IS - 4 SP - 257 EP - 263 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-11867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Wendrich, Astrid A1 - Trela, Christiane A1 - Krause, Martin A1 - Maierhofer, Christiane A1 - Wöstmann, Jens A1 - Milmann, Boris ED - Mazal, P. T1 - Application of ultrasonic and radar tomography for the investigation of the internal structure of masonry T2 - 3rd International Workshop of NDT Experts CY - Prague, Czech Republic DA - 2005-10-10 KW - Masonry KW - Tomography KW - Ultrasonic KW - Radar KW - Non-destructive testing PY - 2005 SN - 80-2142996-8 SP - 299 EP - 313 PB - Univ. of Technology CY - Brno AN - OPUS4-12273 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kohl, Christoph A1 - Streicher, Doreen T1 - Results of reconstructed and fused NDT-data measured in the laboratory and on-site at bridges N2 - Non-destructive testing (NDT) of concrete structures plays an increasing role in civil engineering. This paper presents the results of measurements carried out in the laboratory at BAM and on-site at several bridges using reconstructed and fused radar and ultrasonic echo data sets. In this context different scanning systems, developed for the on-site application of NDT-methods (e.g. reinforced concrete bridges) are introduced. The main object was the demonstration of the improved effectiveness of radar and ultrasonic pulse echo technique due to the automated measurements and the application of new software for the data processing and data visualisation. The results of these measurements show the high potential of reconstruction and data fusion for the improvement and simplification of the interpretability of large data sets measured with impulse-echo methods. KW - Non-destructive testing KW - Prestressed concrete bridges KW - Radar KW - Ultrasonic pulse echo technique KW - Data fusion KW - Scanning system PY - 2006 DO - https://doi.org/10.1016/j.cemconcomp.2006.02.005 SN - 0958-9465 SN - 1873-393X VL - 28 IS - 4 SP - 402 EP - 413 PB - Elsevier CY - Barking, Essex AN - OPUS4-12307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Arndt, Ralf A1 - Röllig, Mathias A1 - Rieck, C. A1 - Walther, A. A1 - Scheel, H. A1 - Hillemeier, B. T1 - Application of impulse-thermography for non-destructive assessment of concrete structures N2 - Impulse-thermography is an active method for quantitative investigations of the near surface region of various structures. It has recently been applied and optimised to applications in civil engineering. By using either an internal or external heat source, parts of the structure under investigation are heated up and the transient heat flux is observed by recording the temperature change at the surface as a function of time. This method is very well suited for the detection of voids and honeycombing in concrete, up to concrete covers of 10 cm as well as for the location of delaminations in multi-layered systems (e.g. plaster on concrete, CFRP-laminates on concrete, asphalt on concrete). Also safety relevant defects like voids in tendon ducts and cracks in concrete could be recognised. KW - Non-destructive testing KW - Impulse-thermography KW - Concrete KW - CFRP-laminates KW - Delamination KW - Tendon duct KW - Voids KW - Compaction faults PY - 2006 DO - https://doi.org/10.1016/j.cemconcomp.2006.02.011 SN - 0958-9465 SN - 1873-393X VL - 28 IS - 4 SP - 393 EP - 401 PB - Elsevier CY - Barking, Essex AN - OPUS4-12359 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane T1 - Non-destructive testing of concrete material properties and concrete structures KW - Non-destructive testing KW - Concrete KW - Material properties KW - Structures PY - 2006 DO - https://doi.org/10.1016/j.cemconcomp.2006.02.002 SN - 0958-9465 SN - 1873-393X VL - 28 IS - 4 SP - 297 EP - 298 PB - Elsevier CY - Barking, Essex AN - OPUS4-12360 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kohl, Christoph A1 - Krause, Martin A1 - Maierhofer, Christiane A1 - Wöstmann, Jens T1 - 2D- and 3D-visualisation of NDT-data using data fusion technique N2 - Non-destructive testing (NDT) of concrete structures is performed using pulse-echo methods. According to the type of the applied waves it can be classified as acoustic (Impact-Echo, Ultrasonics) and electromagnetic methods (Radar). The results are visualised through different imaging processes. This work is performed in the frame of a research project promoted by Deutsche Forschungsgemeinschaft (FOR384). The objective of data fusion is to use the complementary information of the different methods. Radar can detect metallic reflectors in concrete (metallic ducts and concrete reinforcement) very well. This method is not able to locate defects behind these reflectors (injecting defects, defects behind close concrete reinforcement), because the electromagnetic waves are completely reflected at metals. The acoustic methods are able to compensate this deficit i.e. Acoustic waves can penetrate through metal. But acoustic waves in the ultrasonic range are completely reflected by air layers. Air layers have smaller influence on radar propagation, so that both methods complement each other. In order to be able to combine the NDT-data from several methods records at the same volume, the different data setsmodes of signals must be adapted. The ultrasonic and radar data have to be reconstructed with programs based on the Synthetic Aperture Focusing Technique (SAFT) before data fusion. Subsequently, a conversion of the data into a uniform format has to be carried out. This is a prerequisite in order to keep the data exchange between the project partners as simple as possible. After the data sets are imported and transferred into a common reference system, they can be processed with operations according to the purpose of the investigation. Results, which have been achieved in concrete test specimen with radar and ultrasonics, will be presented and will show the feasibility of the data fusion method. KW - Non-destructive testing KW - Radar KW - Ultrasonic KW - Impact-echo KW - Data fusion KW - SAFT PY - 2005 SN - 1359-5997 SN - 1871-6873 VL - 38 IS - 283 SP - 817 EP - 826 PB - Springer CY - Dordrecht AN - OPUS4-11591 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Trappe, Volker A1 - Harbich, Karl-Wolfram T1 - Intralaminar fatigue behaviour of carbon fibre reinforced plastics N2 - A new approach is discussed for characterizing the damage state of FRP with the appearance of micro cracking and its influence on the residual strength. For the quantitative analysis of micro cracking, X-ray refraction topography was used. Fatigue treatment of carbon fibre reinforced plastics (CFRP) laminates were performed to create defined damage states. With regard to real loading conditions of CFRP, studies on tube samples were performed to investigate two dimensional (tension–torsion) loads. A rheological material model was presented which described the increase of micro cracking in ±45° CFRP laminates with a continuum mechanical approach. The correlation between the results of the X-ray refraction topography, the damage parameter of the rheological model and the decrease of residual strength were shown. The inter fibre fracture surface of the investigated CFRP materials was determined with tension–torsion loaded tube specimens of 90°-laminate and a layer-wise strength analysis was done. Micro cracking occurs even at 50% inter-fibre fracture loading and can lead to a distinct strength reduction. The intralaminar fatigue effect itself seems to be an indication for the damage accumulation and the load history. KW - Carbon fibre reinforced plastics KW - Damage accumulation KW - Damage state of CFRP KW - Inter- and intralaminar fatigue KW - Non-destructive testing PY - 2006 DO - https://doi.org/10.1016/j.ijfatigue.2006.02.037 SN - 0142-1123 VL - 28 IS - 10 SP - 1187 EP - 1196 PB - Elsevier CY - Oxford AN - OPUS4-14179 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bovtun, Viktor Petrovic A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Beck, Uwe A1 - Erhard, Anton A1 - Yakymenko, Y. T1 - Ferroelectret non-contact ultrasonic transducers N2 - Dielectric and electromechanical properties of the cellular polypropylene ferroelectret films (EMFIT), combining strong piezoelectric response with a low density and softness, evidence their high potential for the air-coupled ultrasonic applications. The disadvantage of the low coupling factor is compensated by the extremely low acoustic impedance, which provides excellent matching to air and promises efficient sound transmission through the air–transducer interface. The influence of the electrodes on the electromechanical properties was investigated. Electron beam evaporation technology was adapted to the EMFIT films, and films with both-sided Au and Al electrodes were prepared without reducing or suppressing of the electromechanical properties. Finally, prototype transducers based on the EMFIT films were developed. In spite of the simple construction and absence of matching layers, high sensitivity of the EMFIT transducers was proved in the air-coupled ultrasonic experiment. Amplitude and delay time scanned images of the polyethylene step wedge with holes, obtained in both pulse-echo and transmission modes, demonstrate that non-contact ultrasonic imaging and testing with EMFIT transducers is possible. KW - Piezoelectric film KW - Air borne transducer KW - Non-destructive testing PY - 2007 SN - 0947-8396 VL - 88 IS - 4 SP - 737 EP - 743 PB - Springer CY - Berlin AN - OPUS4-15074 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mietz, Jürgen A1 - Fischer, Joachim T1 - Evaluation of NDT methods for detection of prestressing steel damage at post-tensioned concrete structures KW - Prestressing steel KW - Non-destructive testing KW - Post-tensioned concrete KW - Hydrogen-induced stress corrosion cracking PY - 2007 DO - https://doi.org/10.1002/maco.200704074 SN - 0947-5117 SN - 1521-4176 VL - 58 IS - 10 SP - 789 EP - 794 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-16063 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Helmerich, Rosemarie A1 - Röllig, Mathias A1 - Schultz, A. A1 - Vielhaber, J. ED - Jan Bien, ED - Lennart Elfgren, ED - Jan Olofsson, T1 - Quality assurance of CRFP-strengthened reinforced concrete structures using automated thermographic investigation KW - Quality assurance KW - Bridge repair and strengthening KW - Railway bridges KW - Non-destructive testing KW - Automated scanning PY - 2007 SN - 978-83-7125-161-0 SP - 321 EP - 330 PB - Dolnoslaskie Wydawnictwo Edukacyjne CY - Wroclaw, Poland AN - OPUS4-16091 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Helmerich, Rosemarie A1 - Bien, J. A1 - Cruz, P.J.S. ED - Jan Bien, ED - Lennart Elfgren, ED - Jan Olofsson, T1 - A guideline for railway bridge inspection and condition assessment including the NDT toolbox KW - Inspection procedure KW - Bridge condition assessment KW - Railway bridges KW - Non-destructive testing KW - NDT-toolbox PY - 2007 SN - 978-83-7125-161-0 SP - 93 EP - 104 PB - Dolnoslaskie Wydawnictwo Edukacyjne CY - Wroclaw, Poland AN - OPUS4-16092 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Täljsten, B. A1 - Carolin, A. A1 - Helmerich, Rosemarie ED - Jan Bien, ED - Lennart Elfgren, ED - Jan Olofsson, T1 - Rehabilitation of railway bridges KW - Railway bridges KW - Repair and strengthening KW - CFRP-strengthening KW - Non-destructive testing PY - 2007 SN - 978-83-7125-161-0 SP - 303 EP - 312 PB - Dolnoslaskie Wydawnictwo Edukacyjne CY - Wroclaw, Poland AN - OPUS4-16094 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gravenkamp, Hauke A1 - Prager, Jens A1 - Man, H. A1 - Birk, C. A1 - Song, C. ED - Samali, ED - Attard, ED - Song, T1 - Numerical computation of dispersion relations in three-dimensional waveguides N2 - In this paper, a numerical approach to compute the dispersion properties of guided waves in three-dimensional waveguides is presented. The formulation is based on the Scaled Boundary Finite Element Method. The cross section of the waveguide is discretized using higher-order spectral elements. The direction of propagation is described analytically. A Hamiltonian eigenvalue problem is derived for the computation of wave numbers and mode shapes. It is shown that the group velocities of the propagating modes can be obtained directly as the eigenvalue derivatives. Results are presented for a circular rod, where the dispersion curves can be compared with a different approach, and for a waveguide with more complex cross section. T2 - ACMSM 22 - Australasian conference on the mechanics of structures and materials CY - Sydney, Australia DA - 11.12.2012 KW - Guided waves KW - Dispersion KW - Scaled boundary finite element method KW - Non-destructive testing KW - Structural health monitoring PY - 2013 SN - 978-0-415-63318-5 SP - 897 EP - 902 PB - Taylor & Francis AN - OPUS4-27752 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Broomfield, J. A1 - Fischer, Joachim A1 - Mietz, Jürgen A1 - Schneck, U. T1 - Case studies N2 - In this paper, some quite different survey tasks are described, and it can be seen that corrosion surveys will follow a certain scheme of data acquisition (first NDT measurements, than detailed testing on suspect areas), but the individual scope of on-site measurements may have a vast variety according to the local circumstances, and the interpretation always has to refer to a wider set of information than the data readings only. KW - Corrosion surveys KW - Non-destructive testing KW - Reinforcement KW - Concrete KW - Potential mapping KW - Corrosion PY - 2013 DO - https://doi.org/10.1002/maco.201206649 SN - 0947-5117 SN - 1521-4176 VL - 64 IS - 2 SP - 147 EP - 160 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-29730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zerbst, Uwe A1 - Klinger, Christian A1 - Klingbeil, Dietmar T1 - Structural assessment of railway axles - A critical review N2 - The safety assessment of railway axles is based on a two-stage approach: fatigue strength design and regular inspections which, in terms of a general safety philosophy refer to safe-life and damage tolerance concepts. Starting with a recent failure case, a broken axle of a German high speed train, a discussion is presented on issues of both safety levels. These include ideas for finite life design, the treatment of in-service effects on the fatigue strength due to flying ballast damage and corrosion pits, the effect of corrosion on fatigue crack initiation and propagation, potential effects of non-metallic inclusions in steels, the way to detect them by quality control measures and reliability aspects of non-destructive testing with respect to the detection of fatigue cracks. Proposals are made how the safety level could be further improved. KW - Railway axles KW - Safe life design KW - Damage tolerance design KW - Non-destructive testing KW - Flying ballast impact KW - Corrosion KW - Non-metallic inclusions PY - 2013 UR - http://www.sciencedirect.com/science/article/pii/S1350630712002531 SN - 1350-6307 SN - 1873-1961 VL - 35 IS - Special issue on ICEFA V- Part 1 SP - 54 EP - 65 PB - Elsevier Science Publ. CY - Oxford AN - OPUS4-29715 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Brink, Arne A1 - Röllig, Mathias A1 - Wiggenhauser, Herbert T1 - Transient thermography for structural investigation of concrete and composites in the near surface region KW - Impulse thermography KW - Non-destructive testing KW - Quantitative analysis KW - Concrete KW - Composites KW - Civil engineering KW - Simulation KW - Finite differences PY - 2002 SN - 1350-4495 VL - 43 SP - 271 EP - 278 PB - Pergamon Press CY - Oxford AN - OPUS4-1759 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane A1 - Kind, Thomas ED - Koppenjan, S. K. T1 - Application of impulse radar for non-destructive investigation of concrete structures N2 - The application of impulse radar for structural investigation of concrete elements has been increased during the last years related to technical developments, i. e. of high frequency antennas. In this paper, case studies will be presented related to the location of reinforcing bars, tendon ducts and repaired concrete areas in concrete bridges, anchors and dowels in concrete highways and delaminations of layered structures as they are used for non-ballasted railway tracks. It is shown that impulse radar can be applied in case of regular inspection and for searching the cause of damages but also for quality assessment in civil engineering. T2 - 9th GPR 2002 ; 9th International Conference on Ground Penetrating Radar CY - Santa Barbara, CA, USA DA - 2002-04-29 KW - Non-destructive testing KW - Radar KW - Polarisation KW - Civil engineering KW - Concrete KW - Reinforcement KW - Voids KW - Quality assurance PY - 2002 UR - http://cat.inist.fr/?aModele=afficheN&cpsidt=14182375 SN - 0-8194-4522-3 SN - 1605-7422 N1 - Serientitel: SPIE proceedings series – Series title: SPIE proceedings series IS - 4758 SP - 382 EP - 387 PB - SPIE, the International Society for Optical Engineering CY - Bellingham, Wash. AN - OPUS4-1825 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane A1 - Brink, Arne A1 - Röllig, Mathias A1 - Wiggenhauser, Herbert ED - Binda, L. T1 - Transient thermography for non-destructive investigation of building structures in the near surface region T2 - RILEM TC 177-MDT Workshop on On-Site Control and Non-Destructive Evaluation of Masonry Structures CY - Mantova, Italy DA - 2001-11-12 KW - Non-destructive testing KW - Masonry KW - Concrete KW - Impulse thermography KW - Plaster KW - Laminates PY - 2003 SN - 2-912143-34-9 N1 - Serientitel: RILEM proceedings – Series title: RILEM proceedings IS - 26 SP - 251 EP - 261 PB - RILEM Publications CY - Bagneux, France AN - OPUS4-1829 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Harbich, Karl-Wolfram A1 - Hentschel, Manfred P. T1 - Nondestructive Characterization of Monolithic Ceramics by X-Ray Refraction T2 - 7th Euro Ceramics - Conference and Exhibition of the European Ceramic Society (ECerS) CY - Brugge, Belgium DA - 2001-09-09 KW - X-ray refraction KW - Non-destructive testing KW - Porosity KW - Specific surface KW - Pore size PY - 2001 SN - 1013-9826 VL - 206-213 SP - 673 EP - 676 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-1861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fensch-Kleemann, Elisabeth A1 - Harbich, Karl-Wolfram A1 - Hentschel, Manfred P. T1 - Microstructural Characterisation of Porous Ceramics by X-Ray Refraction Topography KW - X-ray refraction topography KW - High pressure mercury intrusion KW - Non-destructive testing KW - Porosity KW - Surface density KW - Specific surface KW - Pore size PY - 2002 SN - 0173-9913 SN - 0196-6219 VL - 79 IS - 11 SP - E35 EP - E38 PB - Göller CY - Baden-Baden AN - OPUS4-1916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kruschwitz, Sabine A1 - Munsch, Sarah Mandy A1 - Strangfeld, Christoph A1 - Wöstmann, Jens A1 - Borchardt, Kerstin T1 - Eignung zerstörungsfreier Messtechnik für die Bestimmung der Belegreife von Estrichen N2 - Die Bestimmung der Belegreife von Estrichen erfolgt im Bauwesen meist unter Verwendung von zerstörenden Verfahren, die Probenentnahmen erfordern und nur punktuelle Daten liefern. Bei anhydritgebundenen Estrichen gelten 0,5 M% und bei zementgebundenen ca. 3,5 M% und höher als belegreifer Feuchtegehalt. Die Belegreife wird als Feuchtegehalt in Masseprozent (M%) bezogen auf die Trockenmasse des Baustoffes angegeben. Zur zerstörungsfreien Feuchtemessung existieren verschiedene einfach zu bedienende Handgeräte, die u. a. auf elektrischen, elektromagnetischen und kapazitiven Methoden beruhen. In dieser Arbeit wurden ein kapazitives (Kugelsonde), ein elektromagnetisches (Mikrowellensensoren) und ein elektrisches Messverfahren (Vierelektroden-Sonde) untersucht. Mit Ausnahme der Vierelektroden-Sonde weisen die Handgeräte keine ausreichende Sensitivität in Bereichen niedriger Feuchtegehalte unterhalb von 1 M% auf und scheinen somit nicht für anhydritgebundene Estriche geeignet zu sein. Für zementgebundene Estriche lassen sich hingegen mit allen getesteten Geräten Änderungen in dem Bereich der Belegreife erfassen. In dieser Arbeit wird zusätzlich die Wasserabgabe in g/m²/Tag als Bezugsgröße herangezogen. Die Wasserabgabe stellt ein geeigneteres Maß für die Schadensträchtigkeit dar und ermöglicht direkte Vergleiche unabhängig von der verwendeten Estrichart. Für alle getesteten Estriche konnte eine Wasserabgabe von ca. 8-10 g/m²/Tag als Belegreifegrenzwert bestimmt werden. N2 - The determination of the readiness for covering of screeds in the construction industry is usually carried out by using destructive methods, which require sampling and only provide punctual data. As non-destructive testing methods, various hand tools exist, which are based on electrical and capacitive methods and are easy to handle. In this study, a capacitive spherical probe, a 4-Electrode probe in Wenner configuration and microwave probes were tested. With the exception of the 4-Electrode probe, the hand instruments do not have sufficient sensitivity in ranges of low humidity below 1 M%, and therefore do not appear to be suitable for anhydrite-bound screeds with a readiness of covering at 0.5 M%. On the other hand, for cement-bound screeds, it is possible to record changes in the range of the readiness of covering. The readiness of covering is usually stated and determined in reference to the relative moisture content. For the purpose of really assessing the risk of damage, we suggest to rather use the “water loss” in g/m²/day. Our results show in direct comparisons that value of approximately 8-10 g/m²/day is a reliable indicator for the readiness for covering of all tested screed types. KW - Estrich KW - Feuchte KW - Zerstörungsfreie Prüfung KW - Calcium-Carbid-Methode KW - Mikrowellensensoren KW - Vierelektroden-Sonde KW - Kapazitive Kugelsonde KW - Screed KW - Moisture KW - Readiness for covering KW - Non-destructive testing KW - Calcium carbide method KW - Microwave KW - 4-electrode probe KW - Capacitive spherical probe PY - 2017 DO - https://doi.org/10.1002/bate.201700051 SN - 1437-0999 N1 - Geburtsname von Munsch, Sarah Mandy: Nagel, S. M. - Birth name of Munsch, Sarah Mandy: Nagel, S. M. VL - 95 IS - 4 SP - 265 EP - 274 PB - Ernst & Sohn AN - OPUS4-43169 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Köhnen, Jörg A1 - Weise, Frank A1 - Wiggenhauser, Herbert ED - Casas, J. R. T1 - Development of an autonomous system for the condition assessment of bridges T2 - 1st International Conference on Bridge Maintenance, Safety and Management ; 1st IABMAS '02 CY - Barcelona, Spain DA - 2002-07-14 KW - Non-destructive testing KW - Climbing Robot KW - Impact-Echo KW - Covermeter KW - Radar KW - Visual Inspection PY - 2002 SN - 84-95999-05-6 SP - 1 EP - 13 PB - International Center for Numerical Methods in Engineering (CIMNE) CY - Barcelona AN - OPUS4-2072 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Köhnen, Jörg A1 - Weise, Frank A1 - Wiggenhauser, Herbert T1 - A climbing robot for the assessment of civil infrastructures T2 - IABSE symposium ; IABSE Symposium Towards a Better Built Environment - Innovation, Sustainability, Information Technology CY - Melbourne, Australia DA - 2002-09-11 KW - Non-destructive testing KW - Climbing Robot KW - Impact-Echo KW - Covermeter KW - Radar KW - Visual Inspection PY - 2002 SN - 3-85748-107-2 N1 - Serientitel: IABSE reports – Series title: IABSE reports IS - 86 SP - 294 EP - 295 PB - IABSE CY - Zürich AN - OPUS4-2071 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bühling, Benjamin A1 - Maack, Stefan A1 - Strangfeld, Christoph T1 - Using sonic crystals to separate the acoustic from the flow field of a fluidic transducer N2 - Ultrasonic testing is a widely applied measurement method in materials research and medicine. Commonly, a transducer is coupled to the specimen directly or via a liquid coupling agent. While reducing acoustic transmission losses significantly, this procedure is time-consuming and cannot be used for sensitive specimens. Air-coupled ultrasound is a viable alternative in such cases, although suffering from very high acoustic transmission losses between transducer, air and specimen. The recently introduced fluidic transducer (FT) generates ultrasound by utilizing the instability of a supersonic air jet switched inside a fluidic amplifier. Since only air is used as the working medium and no vibrating surfaces are used for ultrasound generation, the transducer is able to efficiently generate large acoustic pressure amplitudes. The resulting acoustic field shares its directivity with the ejected high-velocity air jet. Thus, the acoustic energy needs to be redirected from the jet axis in order to make the fluidic transducer applicable to sensitive specimens. In this study, the effectivity of using sonic crystals (SCs) for this redirection is investigated using acoustic and flow measurements. SCs are air-permeable while being reflective to large acoustic frequency bands. It was shown that both a defect waveguide and a mirroring strategy successfully redirected the acoustic field from the air jet. Furthermore, the interaction of flow and SC showed strong acoustic quenching if the SC was placed too close to the FT outlet. Blockage of the jet entrainment due to the SC may result in slightly higher off-axis flow velocities locally, which should be considered in sensitive applications. KW - Air-coupled ultrasound KW - Sonic crystal KW - Fluidics KW - Non-destructive testing KW - Metamaterial KW - Bandgap quenching PY - 2022 DO - https://doi.org/10.1016/j.apacoust.2021.108608 SN - 0003-682X VL - 189 SP - 1 EP - 7 PB - Elsevier CY - Amsterdam AN - OPUS4-54205 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nicolicea, Alberto A1 - Oliveros-Mata, E. S. A1 - Zabila, Y. A1 - Makarov, D. A1 - Melzer, Michael A1 - Pelkner, Matthias T1 - Flexible anisotropic magnetoresistive sensors for novel magnetic flux leakage testing capabilities N2 - Rigid magnetic field sensors such as anisot Hall sensors have been used for years and have become industry standard for electromagnetic non-destructive testing (NDT). Recent technological developments in the field of flexible electronics allow for the fabrication of reshapeable magnetic field sensors on flexible substrates via thin-film deposition or printing. The magnetic properties of these sensors have comparable characteristics to industry-standard rigid magnetic field sensors, with the added ability of adapting to the surface of complex components and scanning in contact with the sample surface. This improves defect detectability and magnetic signal strength by minimizing the scanning lift-off (LO) distance. In this article flexible AMR sensors mounted on a rotative mechanical holder were used to scan a semi-circular ferromagnetic sample with 3 reference defects via magnetic flux leakage (MFL) testing, thus demonstrating the applicability of this type of sensors for the scanning of curved samples. In order to benchmark the performance of these sensors in comparison to industry standard rigid magnetic field sensors, a ferromagnetic sample with 10 reference defects of different depths was scanned employing flexible AMR and rigid GMR sensors. Defects with depths ranging from 110 μm up to 2240 μm were detected with an signal-tonoise ratio (SNR) of 2.7 up to 27.9 (for flexible AMR sensors) and 6.2 up to 72.3 (for rigid GMR sensors), respectively. A 2D magnetometer mapping of the sample with a spatial scanning step of 10 × 50 μm2 (flexible AMR) and 16 × 100 μm2 (rigid GMR) was obtained. The results show that this type of sensor can be used for high-resolution and high-detail mapping of defects on the surface of planar and non-planar ferromagnetic samples since the scanning lift-off distance is equal to the substrate thickness of 20 μm for in-contact scanning. The SNR comparison between flexible and rigid sensors shows that the performance of the flexible AMR sensors employed is not very far behind the performance of the rigid GMR sensors used. KW - Flexible magnetic field sensors KW - Non-destructive testing KW - Magnetic flux leakage KW - Thin film sensor fabrication KW - Defect detection PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603931 DO - https://doi.org/10.1016/j.ndteint.2024.103160 SN - 0963-8695 VL - 146 SP - 1 EP - 15 PB - Elsevier CY - Amsterdam AN - OPUS4-60393 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nicolicea, Alberto A1 - Oliveros-Mata, E. S. A1 - Makarov, D. A1 - Melzer, Michael A1 - Pelkner, Matthias T1 - Flexible anisotropic magnetoresistive sensors for novel eddy current testing applications N2 - The standard method for eddy current testing (ET) of conductive materials relies on using rigid coils. In recent years magnetoresistive (MR) sensors in combination with an excitation wire have become a promising candidate for this application since it would increase the spatial resolution. New developments in flexible electronics have enabled the production of flexible sensors with the novel capability of scanning samples in conformal contact with the surface. In this article flexible anisotropic magnetoresistive (AMR) sensors were used in combination with a thin induction wire to perform eddy current testing of a curved aluminum sample with several defects imprinted on its surface. To benchmark the performance of this new method, a flat sample with reference defects of various dimensions was also scanned using flexible AMR sensors, inductive coils and rigid giant magnetoresistive (GMR) sensors. The results show that this new method of using flexible magnetic field sensors coupled with an excitation wire can easily be applied to the scanning of curved samples, while in the benchmark test employing the flat sample, the performance is not far behind more conventional techniques, with defects with depths down to 30 μm and widths down to 400 μm being detectable with an SNR of 3 (signal magnitude) and 8 (signal phase shift) at the excitation frequency of 50 kHz, and defects with depths down to 30 μm and widths down to 600 μm being detectable with an SNR of 10 (signal magnitude) and 17 (signal phase shift) at 260 kHz. KW - Magnetic field sensors KW - Flexible magnetic field sensors KW - Flexible electronics KW - Non-destructive testing KW - Eddy current testing KW - Thin film sensor fabrication KW - Defect detection KW - Magnetism PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634325 DO - https://doi.org/10.1016/j.measurement.2025.117340 SN - 1873-412X VL - 253, Part A SP - 1 EP - 15 PB - Elsevier CY - Amsterdam AN - OPUS4-63432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lecompagnon, Julien A1 - Rooch, Ludwig A1 - Hassenstein, Christian A1 - Ziegler, Mathias ED - Sakagami, T. ED - Inoue, H. T1 - Total Focusing in the Virtual Wave Domain: 3D Defect Reconstruction Using Spatially Structured Laser Heating N2 - Classical active thermographic testing of industrial goods has mostly been limited to generating 2D defect maps. While for surface or near-surface defect detection, this is a desired result, for deeply buried defects, a 3D reconstruction of the defect geometry is coveted. This general trend can also be well observed in widely used NDT methods (radiography, ultrasonic testing), where the progression from 2D to 3D reconstruction methods has already made profound progress (CT, UT phased array transducers). Achieving a fully 3D defect reconstruction in active thermographic testing suffers from the diffusive nature of thermal processes. One possible solution to deal with thermal diffusion is the application of the virtual-wave concept, which, by solving an inverse problem, allows the diffusiveness to be extracted from the thermographic data in the post-processing stage. What is left follows propagating-wave physics, enabling the usage of well-known algorithms from ultrasonic testing. In this work, we present our progress in the 3D reconstruction of deeply buried defects using spatially structured laser heating in conjunction with applying the well-known total focusing method (TFM) in the virtual-wave domain. T2 - 18th International Workshop on Advanced Infrared Technology and Applications (AITA 2025) CY - Kobe, Japan DA - 15.09.2025 KW - Non-destructive testing KW - Virtual wave concept KW - Laser thermography KW - Thermal thomography PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641463 DO - https://doi.org/10.3390/proceedings2025129054 VL - 129 IS - 1 SP - 1 EP - 5 PB - MDPI CY - Basel AN - OPUS4-64146 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fontoura Barroso, Daniel A1 - Epple, Niklas A1 - Niederleithinger, Ernst T1 - A Portable Low-Cost Ultrasound Measurement Device for Concrete Monitoring N2 - This paper describes a new ultrasonic measuring device called “W-Box”. It was developed based on the requirements of the DFG Forschergruppe (research unit) CoDA for a portable device for monitoring of concrete specimens, models and actual structures using embedded ultrasonic transducers as well as temperature and humidity sensors. The W-Box can send ultrasonic pulses with a variable frequency of 50–100 kHz to one selectable transducer and records signals from up to 75 multiplexed channels with a sample rate of 1 MHz and a resolution of 14 bits. In addition, it measures temperature and humidity with high accuracy, adjustable amplification, restarts automatically after a power failure and can be fully controlled remotely. The measured data are automatically stored locally on-site data quality checks and transferred to remote servers. The comparison of the W-Box with a laboratory setup using commercial devices proves that it is equally reliable and precise, at much lower cost. The W-Box also shows that their measurement capacities, with the used embedded ultrasonic transducers, can reach above 6 m in concrete. KW - Low-cost KW - Coda wave interferometry KW - Ultrasound KW - IoT KW - Non-destructive testing PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546756 DO - https://doi.org/10.3390/inventions6020036 SN - 2411-5134 VL - 6 IS - 2 SP - 1 EP - 17 PB - MDPI CY - Basel, Switzerland AN - OPUS4-54675 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maack, Stefan A1 - Küttenbaum, Stefan A1 - Bühling, Benjamin A1 - Niederleithinger, Ernst T1 - Low frequency ultrasonic dataset for pulse echo object detection in an isotropic homogeneous medium as reference for heterogeneous materials in civil engineering N2 - The dataset presented contains ultrasonic data recorded in pulse echo mode. The investigated specimen is made of the isotropic homogeneous material polyamide and has a drill hole of constant diameter running parallel to the surface, which was scanned in a point grid using an automatic scanner system. At each measuring position, a pitch-catch measurement was performed using a sampling rate of 2 MHz. The probes used are arrays consisting of a spatially separated receiving and in-phase transmitting unit. The transmitting and receiving sides each consist of 12 point-shaped single probes. These dry-point contact (DPC) probes operate according to the piezoelectric principle at nominal frequencies of 55 kHz (shear waves) and 100 kHz (longitudinal waves), respectively, and do not require a coupling medium. The measurements are performed with longitudinal (100 kHz) and transverse (55 kHz) waves with different geometric orientations of the probe on the measurement surface. The data presented in the article provide a valid source for evaluating reconstruction algorithms for imaging in the low-frequency ultrasound range. KW - Non-destructive testing KW - Ultrasound KW - Pulse-echo method KW - Reference material KW - Reconstruction algorithm KW - Validation PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547326 DO - https://doi.org/10.1016/j.dib.2022.108235 VL - 42 SP - 1 EP - 11 PB - Elsevier Inc. AN - OPUS4-54732 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maack, Stefan A1 - Küttenbaum, Stefan A1 - Bühling, Benjamin A1 - Borchardt-Giers, Kerstin A1 - Aßmann, Norman A1 - Niederleithinger, Ernst T1 - Low frequency ultrasonic pulse-echo datasets for object detection and thickness measurement in concrete specimens as testing tasks in civil engineering N2 - The dataset contains raw data gathered with the ultrasonic pulse-echo method on concrete specimens. The surfaces of the measuring objects were automatically scanned point by point. Pulse-echo measurements were performed at each of these measuring points. The test specimens represent two typical testing tasks in construction industry: the detection of objects and the determination of dimensions to describe the geometry of components. By automating the measurement process, the different test scenarios are examined with a high repeatability, precision and measuring point density. Longitu- dinal and transversal waves were used and the geometrical aperture of the testing system was varied. The low-frequency probes operate in a range of up to approximately 150 kHz. In addition to the specification of the geometrical dimensions of the individual probes, the directivity pattern and the sound field characteristics are provided. The raw data are stored in a universally readable format. The length of each time signal (A-scan) is two milliseconds and the sampling rate is two mega-samples per second. The provided data can be used for comparative studies in signal analysis, imag- ing and interpretation as well as for evaluation pur- poses in different, practically relevant testing scenarios. KW - Validation KW - Puls-echo method KW - Ultrasonic KW - Non-destructive testing KW - SAFT KW - Reconstruction algorithm PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575185 DO - https://doi.org/10.1016/j.dib.2023.109233 SN - 2352-3409 VL - 48 SP - 1 EP - 16 PB - Elsevier Inc. AN - OPUS4-57518 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Timofeev, Juri A1 - Azari, H. A1 - Satyanarayana, R. T1 - Controlled Creating of Delaminations in Concrete for Nondestructive Testing N2 - Locating and sizing delaminations is a common inspection task in the maintenance and quality control of construction and rehabilitation. Their detection is an important area of application of nondestructive testing in civil engineering (NDT-CE). To improve this application, NDT test systems and test solutions must be compared, for which specimens containing well-defined delaminations are needed to serve as a reference. Currently, there are no widely accepted procedures available for creating such flaws locally and reproducibly. This study presents procedures for creating artificial delaminations repeatably and as close as possible to natural delaminations. To produce the discontinuities only substances were used which can occur in concrete components and do not affect the application of NDT-CE methods. Ultrasonic pulse-echo (UPE) was used to test the flaws in the specimens. The delaminations were created by applying expansive mortar in prepared through holes. Three specimens with two delaminations each were built and tested using UPE. KW - Concrete KW - Reference KW - Delamination KW - Test specimen KW - Non-destructive testing PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595201 DO - https://doi.org/10.1007/s10921-023-01044-7 SN - 0195-9298 VL - 43 IS - 1 SP - 1 EP - 13 PB - Springer Science and Business Media LLC AN - OPUS4-59520 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lay, Vera A1 - Baensch, Franziska A1 - Skłodowska, Anna A1 - Fritsch, Tobias A1 - Stamm, Michael A1 - Prabhakara, Prathik A1 - Johann, Sergej A1 - Sturm, Patrick A1 - Kühne, Hans-Carsten A1 - Niederleithinger, Ernst T1 - Multi–sensory Monitoring and Non–destructive Testing of New Materials for Concrete Engineered Barrier Systems N2 - The crucial part of nuclear waste storage is the construction of sealing structures made of reliable, safe and well–understood materials. We present an extended analysis of long-term multi–sensory monitoring and non–destructive testing (NDT) inspection of two laboratory specimens aiming at potential materials for sealing structures for nuclear waste repositories. Specimens with a volume of 340 litres made from newly developed alkali–activated materials (AAM) and established salt concrete (SC) were analysed using embedded acoustic emission and wireless radio-frequency identification (RFID) sensors, ultrasonic echo imaging, active thermography, and X–ray computed tomography. The monitoring analysis showed lower heat of reaction and 50% less acoustic emission events in AAM compared to SC. However, due to the surface effects of the AAM material, the number of acoustic emission events increased significantly after approximately two months of monitoring. Subsequently performed NDT inspections reliably located embedded sensors and confirmed the absence of major cracks or impurities. The presented laboratory results show the feasibility and potential of comprehensive NDT monitoring and inspection to characterise cementitious and alternative materials as well as the need for multi–parameter long–term monitoring. Thus, our study demonstrates that tailored NDT investigations will help to develop safe sealing structures for nuclear waste repositories. KW - Radioactive waste KW - Barrier KW - Concrete KW - AAM KW - Non-destructive testing PY - 2024 DO - https://doi.org/10.3151/jact.22.516 SN - 1347-3913 VL - 22 IS - 9 SP - 516 EP - 529 PB - Japan Concrete Institute AN - OPUS4-61461 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -