TY - CONF A1 - Kreutzbruck, Marc A1 - Brekow, Gerhard A1 - Böhm, R. A1 - Montag, Hans-Joachim A1 - Allweins, K. A1 - Strackbein, C. A1 - Bernau, H. T1 - Visualization of material defects - modern approaches in acoustical and electrical NDE-methods N2 - Increasing demands in materials quality and cost effectiveness have led to advanced standards in manufacturing technology. Especially when dealing with high quality standards in conjunction with high throughput quantitative NDE techniques are vital to provide reliable and fast quality control systems. Fast NDE-systems using a high degree of automatisation can be used for both determining the degree of integrity of the components under test and indicating a change of production parameters as well. However, independently of the applied NDE method and the underlying physical principle a reliable visualisation of hidden defects within the component under test is based on a sufficient high signal to noise ratio (SNR) and a high spatial resolution. In this talk we illuminate two standard NDT methods such as Ultrasonic Testing and Eddy Current Testing and show their physical principles also discussing the interaction between sound waves or induced eddy currents with different kinds of material defects. This introduction substantiates the attainable SNR and spatial resolution of both methods with respect to defect sizing and defect classification. As a first future prospect we report on the SAFT-algorithm to improve SNR and spatial resolution paving the way for a flaw sizing approach in ultrasonic inspection. As a second modern NDE approach we represent the use of small magnetoresistance sensor arrays for EC testing of Al-laser welds or for testing superconducting wires. The high sensitivity and small extent of GMR sensors results in a remarkably SNR and spatial resolution offering new visualisation techniques for defect localisation, defect characterization and tomography-like mapping techniques. T2 - ICAMT 2008 - International Conference on Advances in Manufacturing Technology for Young Engineers CY - Madras, Chennai, India DA - 2008-02-06 PY - 2008 IS - CD-ROM (A.4 / I-1) SP - 1 PB - Indian National Academy of Engineering (INAE) CY - Madras, Chennai, India AN - OPUS4-17622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Christina A1 - Pavlovic, Mato A1 - Takahashi, Kazunori A1 - Ewert, Uwe A1 - Rosenthal, Martina A1 - Brekow, Gerhard A1 - Böhm, R. A1 - Ronneteg, U. A1 - Pitkänen, J. T1 - POD Evaluation of NDE Techniques for Canister-Components for Risk Assessment of Nuclear Waste Encapsulation T2 - 6th International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurised Components CY - Budapest, Hungary DA - 2007-10-08 KW - Zerstörungsfreie Prüfung KW - Zuverlässigkeit KW - POD PY - 2008 SN - 978-92-79-08897-1 DO - https://doi.org/10.2790/1274 SN - 1018-5593 SP - 168 EP - 179 AN - OPUS4-18589 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schiebel, J. A1 - Noack, J. A1 - Rödiger, S. A1 - Kammel, A. A1 - Menzel, Friederike A1 - Schwibbert, Karin A1 - Weise, Matthias A1 - Weiss, R. A1 - Böhm, A. A1 - Nitschke, J. A1 - Elimport, A. A1 - Roggenbuck, D. A1 - Schierack, P. T1 - Analysis of three-dimensional biofilms on different material surfaces N2 - Biofilms cause complications and high costs in both industry and medicine. Of particular interest are bacterial infections of prosthetic materials, which usually cannot be eliminated due to the high antibiotic resistance known for bacteria forming biofilms. The search for new materials and coatings with lower colonization potential and antibacterial activity is of great importance to reduce biofilm formation. However, there is no standardized procedure to examine the colonization characteristics of bacteria in the Biofilm state in situ. Here, we describe an automated epifluorescence microscopy system for the semi-quantitative analysis of three-dimensional (3D) biofilms on various surfaces. To analyze adherent bacteria, three materials (glass, steel and titanium) were incubated with bacteria in a flow chamber system. After fluorescence staining of the bacteria, automated image capturing, quantification of the bacteria, measurement of the colonized area and determination of the 3D biofilm height were carried out by using novel software. Furthermore, the materials were examined for their surface topography using white light scanning interferometry. Titanium compared to glass showed a significantly higher number of adherent bacteria. We argue that this was due to the higher microroughness of titanium. The colonized area was in accordance with the number of adherent bacteria and was also significantly larger on titanium coupons compared to glass. Maximum 3D biofilm height on glass coupons was significantly lower compared to the ones on steel and titanium. This novel method enables the standardized, automated investigation of the colonization with bacteria on different materials. This approach can considerably support the characterization of new material surfaces and their innovative coatings by analyzing the amount of attached Bacteria and thickness of biofilms in situ and eliminates the need of conventional cultivation. KW - Biofilm KW - Bacterial adhesion KW - Biofilm quantification KW - Automated analysis PY - 2020 DO - https://doi.org/10.1039/D0BM00455C SP - 1 EP - 11 PB - Royal Society of Chemistry AN - OPUS4-50815 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Harris, J. A1 - Mey, I. P. A1 - Böhm, C. F. A1 - Trinh, T. T. H. A1 - Fink, A. A1 - Bayer, F. A1 - Leupold, S. A1 - Prinz, Carsten A1 - Tripal, P. A1 - Palmisano, R. A1 - Wolf, S. E. T1 - Ultra-smooth and space-filling mineral films generated via particle accretion processes N2 - Nonclassical crystallization typically occurs via the attachment of individual nanoparticles. Intuitively, materials synthesized via this route should exhibit pronounced surface roughness and porosity as a hallmark of the formation process via particle accretion. Here, we demonstrate that nonclassical mineralization of calcium carbonate allows synthesis of ultra-smooth and dense surfaces with unprece-dented root-mean-square roughness of 0.285 nm, simply by con-trolling the hydration state of the nanosized building blocks using Mg doping. High fidelity coating of corrugated substrates can even be achieved. Nonclassical crystallization can thus lead to space-filling inorganic solid-state materials transgressing the implicit porosity commonly expected for particle-driven self-organization processes. KW - Nonclassical crystallization KW - Hydration KW - Particle accretion PY - 2019 DO - https://doi.org/10.1039/c9nh00175a VL - 4 IS - 6 SP - 1388 EP - 1393 PB - Royal Society of Chemistry AN - OPUS4-49488 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sadowski, A. A1 - Seidel, M. A1 - Al-Lawati, H. A1 - Azizi, E. A1 - Balscheit, Hagen A1 - Böhm, M. A1 - Chen, Lei A1 - van Dijk, I. A1 - Doerich-Stavridis, C. A1 - Kunle Fajuyitan, O. A1 - Filippidis, A. A1 - Winther Fischer, A. A1 - Fischer, C. A1 - Gerasimidis, S. A1 - Karampour, H. A1 - Kathirkamanathan, L. A1 - Subramanian, S. A1 - Topkaya, Cem A1 - Wagner, H. N. R. A1 - Wang, J. A1 - Wang, J. A1 - Kumar Yadav, K. A1 - Yun, X. A1 - Zhang, P. T1 - 8-MW wind turbine tower computational shell buckling benchmark - Part 1: An international ‘round-robin’ exercise N2 - An assessment of the elastic-plastic buckling limit state for multi-strake wind turbine support towers poses a particular challenge for the modern finite element analyst, who must competently navigate numerous modelling choices related to the tug-of-war between meshing and computational cost, the use of solvers that are robust to highly nonlinear behaviour, the potential for multiple near-simultaneously critical failure locations, the complex issue of imperfection sensitivity and finally the interpretation of the data into a safe and economic design. This paper reports on an international ‘round-robin’ exercise conducted in 2022 aiming to take stock of the computational shell buckling expertise around the world which attracted 29 submissions. Participants were asked to perform analyses of increasing complexity on a standardised benchmark of an 8-MW multi-strake steel wind turbine support tower segment, from a linear elastic stress analysis to a linear bifurcation analysis to a geometrically and materially nonlinear buckling analysis with imperfections. The results are a showcase of the significant shell buckling expertise now available in both industry and academia. This paper is the first of a pair. The second paper presents a detailed reference solution to the benchmark, including an illustration of the Eurocode-compliant calibration of two important imperfection forms. KW - Wind turbine tower KW - Computational KW - Shell buckling KW - Benchmark PY - 2023 DO - https://doi.org/10.1016/j.engfailanal.2023.107124 SN - 1350-6307 VL - 148 SP - 1 EP - 23 PB - Elsevier Science CY - Oxford AN - OPUS4-57019 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -