TY - CONF A1 - Wosniok, Aleksander A1 - Königsbauer, Korbinian A1 - Krebber, Katerina A1 - Schaller, M.-Barbara A1 - Färber, Jan A1 - Nöther, Nils T1 - Distributed polymer optical fiber sensors using digital I-OFDR for geotechnical infrastructure health monitoring N2 - We present a distributed polymer optical fiber sensor system for deformation monitoring of geotechnical infrastructure. The sensor system is based on the digital incoherent optical frequency domain reflectometry (I-OFDR) for the detection of local strain events along a perfluorinated polymer optical fiber (PF-POF) used as a sensing fiber. For the best possible load transfer, the PF-POFs were integrated onto geosynthetics which pose a sensor carrier for the sensing fiber. By using elastic PF-POF instead of a standard glass fiber as a sensing fiber the strain range of geosynthetics-integrated fiber optic sensors could be extended up to 10 % in accordance with the end-user requirements. T2 - 11th European Workshop on Structural Health Monitoring CY - Potsdam, Germany DA - 10.06.2024 KW - Digital I-OFDR KW - Distributed polymer optical fiber sensor KW - Distributed strain sensing KW - Smart geosynthetics KW - Structural health monitoring PY - 2024 AN - OPUS4-60308 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lohrer, Christian T1 - Primer caps (primer, cap type) - clarification of assignment N2 - Diese Präsentation stellt die gegenwärtige Situation zur Einstufung von primer caps (Anzündhütchen) gemäß Richtlinie 2014/28/EU und UN Model Regulations Rev.23 (Volume I) dar. Spezifische Eigenschaften und Gefährdungen werden dargestellt und eine Abgrenzung zur Richtlinie 2013/29/EU aufgezeigt. T2 - Group of Experts on Pyrotechnic Articles - EU KOM CY - Brussels, Belgium DA - 18.06.2024 KW - Primer caps KW - Anzündhütchen KW - Munition KW - Explosivstoff KW - Pyrotechnik PY - 2024 AN - OPUS4-60317 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weimann, Karin A1 - Bunzel, Jörg-Michael A1 - Mayer, Felix T1 - Entwicklungen im Gipsrecycling N2 - Gips gehört zu den nachgefragtesten Baustoffen und entsprechend steigt der Gipsverbrauch weltweit schon seit Jahrzehnten an. In Deutschland wird der Gipsbedarf seit vielen Jahren zu einem guten Teil durch REA-Gips, einem Nebenprodukt aus der Abgasreinigung von Kohlekraftwerken, gedeckt. Die weitere Gipsversorgung erfolgt größtenteils durch die Nutzung natürlicher Gipsvorkommen. Ein geringer, aber steigender Anteil an RC-Gips aus dem Baustoffrecycling und die Nutzung synthetischer Gipse aus Nebenprodukten anderer Industriezweige sind ebenfalls zu verzeichnen. Aufgrund der nationalen Klimaschutzziele und der damit verbundenen Abschaltung von Kohlekraftwerken wird das REA-Gipsangebot in den nächsten Jahren jedoch weiter deutlich zurückgehen, so dass andere Gipsquellen erschlossen werden müssen. Abhängig von der Lebensdauer der verwendeten Gipsprodukte im Bausektor ist infolge des in den vergangenen Jahren erfolgten Anstiegs des Gipsverbrauchs auch mit einer Zunahme von Gipsresten in Bau- und Abbruchabfällen zu rechnen. Im Hinblick auf eine bevorstehende Verknappung von Gips wird die Rückgewinnung dieser Gipse aus Bau- und Abbruchabfällen immer wichtiger. Das Recycling von Gipskartonplatten ist mittlerweile eine etablierte Technik und wird bereits seit einigen Jahren in industriellem Maßstab durchgeführt. Außerdem werden neue Verfahren zur Wiederverwertung weiterer Gipsprodukte aus Rück- und Umbaumaßnahmen untersucht. Von besonderem Interesse sind verschiedene Arten von Gipsplatten, da sie gut für selektiven Rückbau geeignet sind. Daher können sie vergleichsweise frei von Verunreinigungen oder Störstoffen zurückgewonnen werden, was für das Gipsrecycling besonders wichtig ist. In dem vom Bundesministerium für Bildung und Forschung geförderten Forschungsprojekt "GipsRec 2.0" werden technische, wirtschaftliche und ökologische Aspekte des Recyclings von Gipsfaserplatten sowie von verschiedenen Synthesegipsen untersucht und bewertet. Die Aufbereitung von Gipsfaserplatten erfolgte im halbtechnischen Maßstab, an verschiedenen potentiellen Ausgangsstoffen für synthetische Gipse wurden Laborversuche durchgeführt. Erfolgversprechende Verfahrenswege werden ökobilanziell bewertet. Ziel dieser Arbeiten ist die Erschließung der Sekundärrohstoffpotenziale von weiteren Quellen für die RC-Gipsproduktion um mit einer Steigerung des Gipsrecyclings die in naher Zukunft durch die Reduktion der REA-Gips-Bereitstellung entstehende Lücke in der Rohstoffversorgung zu verringern. T2 - 21. ibausil 2023 CY - Weimar, Germany DA - 13.09.2023 KW - Baustoffrecycling KW - Sekundärgipse KW - Ökobilanz PY - 2023 AN - OPUS4-60314 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander A1 - Schukar, Marcus A1 - Wang, Bin A1 - Breithaupt, Mathias A1 - Kriegsmann, Andreas A1 - Woody, Paul T1 - Distributed fiber optic strain sensing for structural health monitoring of 70 MPa hydrogen vessels N2 - We report on the development and testing of 70 MPa hydrogen pressure vessels with integrated fiber optic sensing fibers for automotive use. The paper deals with the condition monitoring of such composite pressure vessels (CPVs) using the optical backscatter reflectometry (OBR) applied for a distributed fiber optic strain sensing along fully integrated polyimide-coated single-mode glass optical fiber (SM-GOF). The sensing fibers were embedded into the vessel structure by wrapping them over the polymer liner during the manufacturing process of the carbon fiber reinforced polymer (CFRP). Detecting local strain events by the integrated fiber optic sensors can be an opportunity for monitoring the material degradation of CPVs under static and cyclic loading. T2 - 11th European Workshop on Structural Health Monitoring CY - Potsdam, Germany DA - 10.06.2024 KW - Fiber optic sensor KW - Distributed strain sensing KW - Composite pressure vessel KW - Structural health monitoring KW - Fiber-reinforced plastics PY - 2024 AN - OPUS4-60307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Martin A1 - Kromm, Arne A1 - Kannengießer, Thomas A1 - Dittmann, Florian A1 - Varfolomeev, Igor T1 - Eigenspannungsabbau mittels LTT – Schweißzusätzen unter Berücksichtigung der Nahtgeometrie N2 - Low Transformation Temperature (LTT)-Schweißzusätze sind ein innovativer Ansatz, um Eigenspannungen in Schweißnähten zu reduzieren. Dieser Vortrag behandelt neben den Einfluss der LTT-Schweißzusätze auch deren Naht-Ausführungen. Die unterschiedlichen LTT-Nahtgeometrien haben einen signifikanten Einfluss auf den Eigenspannungsabbau in der Schweißnaht und der Wärmeeinflusszone (WEZ). T2 - SFB 1120 Summer School CY - Steinfeld, Germany DA - 11.06.2024 KW - LTT (Low Transformation Temperature) KW - Eigenspannungen KW - Ermüdungsfestigkeit KW - Aufmischung PY - 2024 AN - OPUS4-60306 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Topolniak, Ievgeniia T1 - Micropatterning of mussel-inspired materials - Empower selective functionality N2 - Surface-modification platforms that are universally applicable are vital for the development of new materials, surfaces, and nanoparticles. Mussel-inspired materials (MIMs) are widely used in various fields because of their strong adhesive properties and post-functionalization reactivity. However, conventional MIM coating techniques have limited deposition selectivity and lack structural control, which has limited their use in microdevices that require full control over deposition. To overcome these limitations, we developed a micropatterning technique for MIMs using multiphoton lithography, which does not require photomasks, stamps, or multistep procedures. This method enables the creation of MIM patterns with micrometer resolution and full design freedom and paves the way for innovative applications of MIMs in various multifunctional systems and microdevices, such as microsensors, MEMS, and microfluidics. T2 - BioCHIP Berlin - International Forum on Biochips and Microfabrication CY - Berlin, Germany DA - 28.05.2024 KW - Mussel inspired materials KW - Multiphoton lithography KW - Two photon polymerisation PY - 2024 AN - OPUS4-60254 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Martin A1 - Kromm, Arne A1 - Kannengiesser, Thomas A1 - Dittmann, Florian A1 - Varfolomeev, Igor T1 - Influence of the weld geometry on the residual stress reduction using low transformation temperature welding consumables N2 - Low transformation temperature (LTT) welding consumables offer an innovative approach to increase the fatigue strength of welded high-strength steel structures. LTT welding consumables are characterized by a martensitic phase transformation near ambient temperature, which generates compressive residual stresses in the weld and heat affected zone (HAZ). The aim is to achieve a weld geometry, which generate high compressive residual stresses at the fatigue crack critical weld toe. Longitudinal stiffeners were gas metal arc welded using a conventional welding consumable; the base material was a high strength steel S700M. A chromium-nickel alloyed LTT consumable was deposit subsequently just on front sides of the stiffeners. Different welding parameters led to varying cross sections of the weld. The residual stresses were determined using X-ray diffraction (XRD) in the crack critical HAZ. When using only the conventional, the HAZ is characterized by high tensile residual stresses. The additional application of the LTT alloy leads to a significant reduction of the tensile residual stresses. Depending on the weld geometry, even compressive residual stresses can be observed at the weld toe T2 - ECRS 2024 CY - Prague, Czech Republic DA - 03.06.2024 KW - LTT (Low Transformation Temperature) KW - Residual stress reduction KW - Fatigue PY - 2024 AN - OPUS4-60305 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mohr, Gunther T1 - Towards component safety in laser powder bed fusion of metals N2 - The thermal history during additive manufacturing of complex components differs significantly from the thermal history of geometrically primitive test specimens. This can result in differences in properties that can lead to different material behavior. In this talk, the concept of representative test specimens is introduced, which enables the transfer of thermal histories from complex geometries to simple geometries, which can lead to better comparability of material properties. T2 - Additive Alliance CY - Hamburg, Germany DA - 05.03.2024 KW - Additive manufacturing KW - Heat accumulation KW - Laboratory specimens KW - In situ monitoring KW - Representative specimens KW - Thermal history PY - 2024 AN - OPUS4-60263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Suárez Ocano, Patricia A1 - Ávila Calderón, Luis A. A1 - Rehmer, Birgit A1 - Mohr, Gunther A1 - Evans, Alexander A1 - Skrotzki, Birgit T1 - Effect of heat treatment on the hierarchical microstructure and properties of 316L stainless steel produced by Laser Powder Bed Fusion (PBF-LB/M). N2 - Laser Powder Bed Fusion (PBF-LB/M) of AISI 316L stainless steel has gained popularity due to its exceptional capacity to produce complex geometries and hierarchical microstructures, which can increase the yield strength while maintaining good ductility. Nevertheless, owing to high thermal gradients encountered during the process, the as printed 316L stainless steel often exhibit microstructural heterogeneities and residual stresses, which can limit its performance in demanding environments. Hence, employing heat treatments which balance the reduction of residual stresses while retaining improved static strength may be beneficial in various scenarios and applications. This study investigates the impact of post-processing heat treatments on the microstructure of 316L stainless steel manufactured via PBF-LB/M, along with its correlation with micro-hardness properties. To this end, 6 different heat treatments, i.e., 450 °C for 4h, 700 °C for 1h, 700 °C for 3h, 800 °C for 1h, 800 °C for 3h, and 900 °C for 1h, were applied to different specimens and Vickers hardness measurements (HV1) were performed in all states. At 800 °C, although the cellular structure appears to be retained, there is an observable increase in cellular size. However, while treatments exceeding 900 °C indicate no significant grain growth compared to other conditions, the cellular structure is entirely dissolved, which leads to a reduced Vickers hardness. The effect of the heat treatments on other microstructural features such as grain size and morphology, melt pool boundaries (MPB), crystallographic texture, chemical segregation, dispersoids and phase stability are also discussed in the present work T2 - 4th Symposium on Materials and Additive Manufacturing CY - Berlin, Germany DA - 12.06.2024 KW - Additive manufacturing KW - Heat treatment KW - Microstructure PY - 2024 AN - OPUS4-60304 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Jakob A1 - Evans, Alexander A1 - Luzin, V. A1 - Čapek, J. A1 - Polatidis, E. A1 - Bruno, Giovanni T1 - Laser Powder Bed Fusion: Fundamentals of Diffraction-Based Residual Stress Determination N2 - The general term additive manufacturing (AM) encompasses processes that enable the production of parts in a single manufacturing step. Among these, laser powder bed fusion (PBF-LB) is one of the most commonly used to produce metal components. In essence, a laser locally melts powder particles in a powder bed layer-by-layer to incrementally build a part. As a result, this process offers immense manufacturing flexibility and superior geometric design capabilities compared to conventional processes. However, these advantages come at a cost: the localized processing inevitably induces large thermal gradients, resulting in the formation of large thermal stress during manufacturing. In the best case, residual stress remains in the final parts produced as a footprint of this thermal stress. Since residual stress is well known to exacerbate the structural integrity of components, their assessment is important in two respects. First, to optimize process parameter to minimize residual stress magnitudes. Second, to study their effect on the structural integrity of components (e.g., validation of numerical models). Therefore, a reliable experimental assessment of residual stress is an important factor for the successful application of PBF-LB. In this context, diffraction-based techniques allow the non-destructive characterization of the residual stress. In essence, lattice strain is calculated from interplanar distances by application of Braggs law. From the known lattice strain, macroscopic stress can be determined using Hooke’s law. To allow the accurate assessment of the residual stress distribution by such methods, a couple of challenges in regard of the characteristic PBF-LB microstructures need to be overcome. This presentation highlights some of the challenges regarding the accurate assessment of residual stress in PBF-LB on the example of the Nickel-based alloy Inconel 718. The most significant influencing factors are the use of the correct diffraction elastic constants, the choice of the stress-free reference, and the consideration of the crystallographic texture. Further, it is shown that laboratory X-ray diffraction methods characterizing residual stress at the surface are biased by the inherent surface roughness. Overall, the impact of the characteristic microstructure is most significant for the selection of the correct diffraction elastic constants. In view of the localized melting and solidification, no significant gradients of the stress-free reference are observed, even though the cell-like solidification sub-structure is known to be heterogeneous on the micro-scale. T2 - 4th Symposium on Materials and Additive Manufacturing CY - Berlin, Germany DA - 12.06.2024 KW - Additive Manufacturing KW - Residual Stress KW - Electron Backscatter Diffraction KW - Laser Powder Bed Fusion PY - 2024 AN - OPUS4-60294 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -