TY - CONF A1 - Maierhofer, Christiane A1 - Krankenhagen, Rainer A1 - Röllig, Mathias A1 - Riemer, Stefanie A1 - Gower, M. A1 - Baker, G. A1 - Lodeiro, M. A1 - Knazovicka, L. A1 - Blahut, A. A1 - Monte, C. A1 - Adibekyan, A. ED - Gutschwager, B. T1 - Characterisation of artificial and natural defects in fibre reinforced plastics designed for energy applications using active thermography N2 - Amongst various other NDT methods, within the EMRP-project ‘VITCEA’ active thermography is validated for testing of CFRP and GFRP structures constructed for energy application. In this contribution, the optical and thermal properties of CFRP and GFRP reference defect artefact (RDA) and natural defects artefact (NDA) test specimens are characterized. Different excitation techniques and techniques for data analysis are compared for optimizing the number of detected defects. T2 - 19th World Conference on Non-destructive Testing (WCNDT) CY - Munich, Germany DA - 13.06.2016 KW - Active thermography KW - CFRP KW - GFRP KW - Artificial and natural defects PY - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-370207 UR - http://www.ndt.net/article/wcndt2016/papers/we2i4.pdf SN - 978-3-940283-78-8 VL - BB 158 SP - Paper we2i4, 1 EP - 9 PB - DGZfP CY - Berlin AN - OPUS4-37020 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maierhofer, Christiane A1 - Röllig, Mathias A1 - Steinfurth, Henrik A1 - Augustin, Sven A1 - Mecke, R. A1 - Schiller, M. A1 - Kernchen, A. A1 - Kalisch, U. A1 - Meinhardt, J. A1 - Hennen, C. A1 - Groll, E. T. A1 - Arnold, T. T1 - Characterisation of historic façades using active thermography with solar heating and optical methods N2 - Active thermography is well suited for the detection of delaminations and cracks in façade elements like plaster and tiles. Not only artificial heating but also solar heating can be used if the adjustment of the façade and the weather conditions are suitable. Optical methods like laser scanners, photogrammetric methods and crack tracking sensors are providing geometrical 3D data which can be used for a 3D mapping of thermograms and for providing data with higher geometrical resolution. Thus, by the combination and fusion of these data, a comprehensive mapping and monitoring of damages of façade systems is possible. T2 - 19th World Conference on Non-destructive Testing (WCNDT) CY - München, Germany DA - 13.06.2016 KW - Non-destructive testing KW - Active thermography KW - Solar heating KW - Historic facades KW - Optical methods PY - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-366833 SN - 978-3-940283-78-8 VL - BB 158 SP - Mo.2.C.2., 1 EP - 8 PB - DGZfP CY - Berlin AN - OPUS4-36683 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Doroshtnasir, Manoucher A1 - Worzewski, Tamara A1 - Krankenhagen, Rainer A1 - Röllig, Mathias T1 - On-site inspection of potential defects in wind turbine rotor blades with thermography N2 - Recurrent non-destructive testing inspections are necessary to prevent damages in wind turbine rotor blades, but so far, there is no established method that detects defects in blades from greater distances – although this becomes increasingly important in the context of hardly accessible offshore wind parks. Thermography is a promising method for detecting subsurface defects, but various challenges arise when this method is applied on-site to turbine blades in operation. Disturbing influences from the environment easily lead to a misinterpretation of thermograms (i.e. thermographic images), such as thermal signatures caused by reflections, dirt and other superficial inhomogeneities. This study explores several problems and effects that arise, when (rotating) blades are monitored with thermography. It will then be demonstrated that a meaningful defect inspection in this scenario is essentially restricted to a procedure following three steps: Firstly, calculating the so-called difference thermograms of all blade pairs for eliminating disturbing reflections. Secondly, identifying potentially relevant signals, which are associated neither with structural features nor with dynamical effects, and the identification of these signals’ allocations (through comparison of all difference thermograms with each other). And thirdly, comparing these signals with (processed) photos for excluding incorrect indications by surface effects. Unlike common thermographic analysis methods, which typically only include an aspect of this procedure, the composition presented in this contribution constitutes an advanced technique for minimizing disturbing influences in thermograms. The proposed thermographic technique enables the detection of potential subsurface defects within rotating rotor blades from greater distances – such as from the ground, air crafts or vessels. KW - NDT KW - Thermographic inspection KW - Wind turbine rotor blade KW - GFRP PY - 2016 U6 - https://doi.org/10.1002/we.1927 SN - 1095-4244 VL - 19 IS - 8 SP - 1407 EP - 1422 PB - John Wiley & Sons, Ltd. CY - Hoboken, New Jersey, USA AN - OPUS4-37291 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Röllig, Mathias A1 - Krankenhagen, Rainer A1 - Myrach, Philipp T1 - Comparison of quantitative defect characterization using pulse-phase and lock-in thermography N2 - Using optical excitation sources for active thermography enables a contactless, remote, and non-destructive testing of materials and structures. Currently, two kinds of temporal excitation techniques have been established: pulse or flash excitation, usingmostly flash lamps; and periodic or lock-in excitation, using halogen lamps, LED, or laser arrays. From the experimental point of view, both techniques have their advantages and disadvantages. Concerning the comparison of the testing results of both techniques, only very few studies have been performed in the past. In this contribution, the phase values obtained at flat bottom holes in steel and CFRP and the spatial resolution measured at crossed notches in steel using flash and lock-in excitation are compared quantitatively. KW - Nondestructive testing KW - Thermal imaging KW - Infrared imaging KW - Phase measurement KW - Metals KW - Polymers PY - 2016 UR - https://www.osapublishing.org/ao/viewmedia.cfm?URI=ao-55-34-D76&seq=0&origin=search U6 - https://doi.org/10.1364/AO.55.000D76 SN - 1559-128X SN - 0003-6935 SN - 1539-4522 VL - 55 IS - 34 SP - D76 EP - D86 PB - OSA Publishing CY - Washington, D.C. 20036-1012 USA AN - OPUS4-38184 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Worzewski, Tamara A1 - Röllig, Mathias A1 - Maierhofer, Christiane A1 - Doroshtnasir, M. A1 - Steinfurth, H. A1 - Krankenhagen, Rainer T1 - Thermographic inspection of a wind turbine rotor blade segment utilizing natural conditions as excitation source, Part I: Solar excitation for detecting deep structures in GFRP N2 - This study evaluates whether subsurface features in rotor blades, mainly made of Glass Fibre Reinforced Plastics (GFRP), can generally be detected with ‘‘solar thermography”. First, the suitability of the sun is tested for acting as a heat source for applying active thermography on a 30 mm thick GFRP test specimen. Second, a defective rotor blade segment is inspected outdoors under ideal natural conditions using the sun as excitation source. Additionally, numerical FEM-simulations are performed and the comparability between experiment and simulation is evaluated for outdoor measurements. KW - NDT KW - Numerical simulation KW - Solar excitation KW - On-site inspection KW - Structural health monitoring PY - 2016 U6 - https://doi.org/10.1016/j.infrared.2016.04.011 SN - 1350-4495 VL - 76 SP - 756 EP - 766 PB - Elsevier B.V. AN - OPUS4-36076 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krankenhagen, Rainer A1 - Röllig, Mathias A1 - Worzewski, Tamara A1 - Doroshtnasir, Manoucher T1 - Thermographic rotor blade inspection from larger distances – a promising tool for the maintenance of wind turbines N2 - The permanently increasing number of wind turbines requires suited inspection and monitoring methods to ensure liability and security. Concerning the inspection of ro-tor blades, only manual inspections are state of the art. Thermographic Testing (TT) has the potential to detect typical failures and damages on rotor blades. The paper presents some results of onsite measurements carried out as “passive thermogra-phy”, i.e. without a defined heating procedure. Due the totally contactless meas-urement principle, TT can be applied to rotating blades as well as to resting blades. Both methods will be compared with respect to their possible realization. T2 - WCNDT 2016 CY - Munich, Germany DA - 13.06.2016 KW - Wind turbine rotor blade KW - Thermographic inspection KW - Passive thermography KW - Nondestructive testing PY - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-366331 SN - 978-3-940283-78-8 SP - We.4.D.4., 1 EP - 8 AN - OPUS4-36633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maierhofer, Christiane A1 - Röllig, Mathias A1 - Steinfurth, Henrik A1 - Krankenhagen, Rainer A1 - Myrach, Philipp A1 - Mecke, R. A1 - Schiller, M. A1 - Seidl, T. A1 - Kernchen, A. A1 - Kalisch, U. A1 - Meinhardt, J. A1 - Hennen, C. A1 - Arnold, T. A1 - Groll, T. T1 - 3D-Kartierung von Bauwerksoberflächen mit optischen und thermografischen Verfahren N2 - In diesem Beitrag werden Verfahren und Strategien basierend auf optischen und thermografischen Methoden zur Lokalisierung, Erfassung und Bewertung von Putzablösungen, Ablösungen von Fassadenelementen und Rissen vorgestellt. Abgelöste Fassadenbereiche und Risse zeigen dabei sowohl geometrische als auch thermische Auffälligkeiten, die im Rahmen eines Monitoring auch über größere Zeiträume verfolgt werden können. Als optische Verfahren werden die trackingbasierte taktile 3D‐Erfassung von Oberflächenmerkmalen und die Stereophotogrammetrie eingesetzt. Zur Charakterisierung verdeckter Ablösungen und Bauteile wird die aktive Thermografie mit natürlicher und künstlicher Erwärmung der Bauteiloberfläche verwendet. Systematische Untersuchungen an Probekörpern und Fallstudien (Magdeburger Dom, Wandbild in Cobbelsdorf, Giebichensteinbrücke) zeigen, wie u. a. mit der Verfahrenskombination die Schäden charakterisiert werden können. T2 - Interdisziplinäre Forschung in der Denkmalpflege - 20 Jahre IDK - CY - Dresden, Germany DA - 31.05.2016 KW - Monitoring KW - Risse KW - Ablösungen KW - Aktive Thermografie KW - Optische 3D-Erfassung PY - 2016 SN - 978‐3‐9811706‐2‐7 SP - 141 EP - 156 CY - Dresden AN - OPUS4-37508 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maierhofer, Christiane A1 - Myrach, Philipp A1 - Röllig, Mathias A1 - Jonietz, Florian A1 - Illerhaus, Bernhard A1 - Meinel, Dietmar A1 - Richter, U. A1 - Miksche, R. ED - Chimenti, Dale E. ED - Bond, Leonard J. T1 - Characterization of pores in high pressure die cast aluminum using active thermography and computed tomography N2 - Larger high pressure die castings (HPDC) and decreasing wall thicknesses are raising the issue of casting defects like pores in aluminum structures. Properties of components are often strongly influenced by inner porosity. As these products are being established more and more in lightweight construction (e.g. automotive and other transport areas), non-destructive testing methods, which can be applied fast and on-site, are required for quality assurance. In this contribution, the application of active thermography for the direct detection of larger pores is demonstrated. The analysis of limits and accuracy of the method are completed by numerical simulation and the method is validated using computed tomography. T2 - 42nd Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Minneapolis, Minnesota, USA DA - 26.07.2015 KW - flash thermography KW - aluminum KW - pores KW - computed tomography PY - 2016 SN - 978-0-7354-1353-5 U6 - https://doi.org/10.1063/1.4940580 VL - 1706 SP - 110009-1 EP - 110009-8 PB - AIP Publishing LLC CY - Melville, New York, USA AN - OPUS4-35848 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maierhofer, Christiane A1 - Krankenhagen, Rainer A1 - Röllig, Mathias A1 - Rehmer, Birgit A1 - Gower, M. A1 - Baker, G. A1 - Lodeiro, M. A1 - Aktas, A. A1 - Knaszovicka, L. A1 - Blahut, A. A1 - Monte, C. A1 - Adibekyan, A. A1 - Gutschwager, B. T1 - Characterisation of artificial defects in CFRP and GFRP sheets designed for energy applications using active thermography N2 - The increased use of fibre-reinforced plastic (FRP) composites for improved efficiency and reliability in energy related applications e.g. wind and marine turbine blades, nacelles, oil and gas flexible risers, also increases the demand for innovative non-destructive testing technologies. Thus, in order to achieve increased acceptance of suited and optimized non-destructive testing (NDT) methods in industry, the European Metrology Research Programme (EMRP) project ENG57 Validated Inspection Techniques for Composites in Energy Applications (VITCEA) deals with the development and validation of innovative NDT technologies. In this contribution, results concerning thermographic investigations at test specimens during tensile loading and active thermography testing after tensile loading are presented. Additionally, the determination of the optical properties (relative transmittance and directional spectral emissivity) of CFRP and GFRP test specimens is described. T2 - Conference QIRT 2016 CY - Gdansk, Poland DA - 04.07.2016 KW - Active thermography KW - CFRP KW - GFRP KW - Validation of methods PY - 2016 UR - http://qirt.gel.ulaval.ca/archives/qirt2016/papers/076.pdf U6 - https://doi.org/10.21611/qirt.2016.076 SN - 2371-4085 SP - Paper 076, 527 EP - 536 CY - Quebec, Canada AN - OPUS4-37512 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -