TY - THES A1 - Charmi, Amir T1 - A multiscale numerical framework for the simulation of anistropic material response of additively manufactured stainless steel 316L undergoing large plastic deformation N2 - Additive manufacturing (AM) offers significantly greater freedom of design compared to conventional manufacturing processes since the final parts are built layer by layer. This enables metal AM, also known as metal 3D printing, to be utilized for improving efficiency and functionality, for the production of parts with very complex geometries, and rapid prototyping. However, despite many technological advancements made in recent years, several challenges hinder the mass adoption of metal AM. One of these challenges is mechanical anisotropy which describes the dependency of material properties on the material orientation. Therefore, in this work, stainless steel 316L parts produced by laser-based powder bed fusion are used to isolate and understand the root cause of anisotropy in AM parts. Furthermore, an efficient and accurate multiscale numerical framework is presented for predicting the deformation behavior of actual AM parts on the macroscale undergoing large plastic deformations. Finally, a novel constitutive model for the plastic spin is formulated to capture the influence of the microstructure evolution on the material behavior on the macroscale. KW - Additive Fertigung KW - Austenitischer Stahl KW - Finite-Elemente-Methode KW - Mehrskalenmodell KW - Simulation PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:gbv:wim2-20240207-173356-002 DO - https://doi.org/10.25643/dbt.59550 SP - 1 EP - 163 PB - Bauhaus-Universität Weimar CY - Weimar AN - OPUS4-59511 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Glauer, M. A1 - Schilling, Markus A1 - Stappel, M. T1 - A practical ontology development guide N2 - Knowledge representation is becoming increasingly important in view of the large amounts of data that are handled in the modern scientific landscape. Many of the domains that have most readily realised this problem and worked on potential solutions have been the domain of biochemistry. And although the developments sought here were not accompanied by philosophers, this process organically led to the development of formal and structured representations of certain domains. While the resulting structures were not the first formal ontologies, they are ones that are still in wide use to this day. These approaches have led to major advances in the organisation, structuring and communication of scientific results. Since then, a variety of other domains have tried to adapt a similar process and develop their own ontologies. However, the development of ontologies from the domain of biochemistry was the result of a years-long process that also involved a large number of errors and course corrections. One of the greatest challenges is also one of the greatest strengths of ontologies: Interoperability with other ontologies. To ensure this interoperability, ontologies must follow certain principles. In the field of biochemistry, the OBO Foundry has established itself, which offers functionalities for a rich network of ontologies from the domain, but at the same time also defines rules. The purpose of this document is to define a similar set of rules for open ontology development, but which addresses a broader domain and at the same time lowers the barrier of entry for new ontology developers. To this end, we will outline a workflow that can be used to build new ontologies more efficiently. This workflow is based not only on our own years of experience in ontology development, but also on the rules of external experts such as the OBO Foundry. KW - Ontology KW - Data integration KW - Ontologie KW - Data interoperability PY - 2024 UR - https://scientific-ontology-network.github.io/ UR - https://github.com/scientific-ontology-network/ontology-development-guide/releases/download/v0.1.0/ontology-guide.pdf SP - 1 EP - 27 PB - GitHub CY - San Francisco ET - Version 0.1 AN - OPUS4-61140 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Singh, Shobhit T1 - Accelerated Creep Testing in High- Temperature Alloys N2 - This study introduces an innovative method for efficiently determining the creep properties of high-temperature materials through high-throughput testing, employing digital image correlation [1,2]. The focus is on the AlCoCrFeNiTi alloy [3-5], synthesized by directional solidification, known for its exceptional strength and unique properties. Experimental investigations, including compression, and bending creep tests, were conducted at 750°C. Capitalizing on the inhomogeneous stress and strain distribution within a cantilever subjected to bending, we leverage this characteristic to extract multiple creep curves from a single test. Stresses at key points were determined using existing analytical solutions [5,6]. Uniaxial tests spanning 300 to 500 MPa initial stress were complemented by bending tests designed to induce similar stress levels. A detailed comparison between bending and uniaxial creep is presented, including the results of verification studies on additional alloys. This methodology not only expedites testing but also minimizes material usage, energy consumption, and manual labour. This research showcases a reliable and time-efficient approach to exploring the creep behavior of high-temperature materials. The technique is particularly advantageous for characterizing precious alloys with limited dimensions. Microstructural heterogeneity may exist in specimens tested under bending load, however, it can still be correlated to the mechanical properties with modern high-resolution characterization methods. Stress and resulting strain can be directly compared in a single specimen, ensuring uniform manufacturing, and heating history. This method eliminates the possible errors due to testing with different rigs, which could impair the accuracy of studies based on individual tests. T2 - International Conference on Creep and Fracture of Engineering Materials and Structures CY - Bengaluru, KA, India DA - 28.07.2024 KW - Digital Image Correlation KW - Creep KW - High-Temperature Materials PY - 2024 AN - OPUS4-60925 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bayerlein, Bernd T1 - Adapting FAIR Practices in Materials Science: Digital Representation of Material-Specific Characterization Methods N2 - Age-hardenable aluminum alloys undergo precise heat treatments to yield nanometer-sized precipitates that increase their strength and durability by hindering the dislocation mobility. Tensile tests provide mechanical properties, while microstructure evaluation relies on transmission electron microscopy (TEM), specifically the use of dark-field TEM images for precise dimensional analysis of the precipitates. However, this manual process is time consuming, skill dependent, and prone to errors and reproducibility issues. Our primary goal is to digitally represent these processes while adhering to FAIR principles. Ontologies play a critical role in facilitating semantic annotation of (meta)data and form the basis for advanced data management. Publishing raw data, digital workflows, and ontologies ensures reproducibility. This work introduces innovative solutions to traditional bottlenecks and offers new perspectives on digitalization challenges in materials science. We support advanced data management by leveraging knowledge graphs and foster collaborative and open data ecosystems that potentially revolutionize materials research and discovery. T2 - TMS - Specialty Congress 2024 CY - Cleveland, Ohio, US DA - 16.06.2024 KW - FAIR KW - Research Data Management KW - Semantic Interoperability KW - Ontologies KW - Materials and Processes Data Reusability PY - 2024 AN - OPUS4-60375 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zocca, Andrea T1 - Additive manufacturing of ceramics from water-based feedstocks with low binder content N2 - A major challenge in the current ceramic additive manufacturing is the debinding of the printed parts, which is often associated with long process times and limitations in size and wall thickness. Binder jetting, a powder-based AM technology, can in principle generate thick-walled parts with a low amount of organics and with high productivity. However, this technology is often not capable of handling the fine powders required as raw materials for most technical ceramics. In this context, the "layerwise slurry deposition" (LSD-print) has been developed as a layer deposition method using water-based ceramic slurry feedstocks, enabling binder jetting also for advanced ceramic materials. LSD-print thus combines the high-speed printing of binder jetting with the possibility of producing a variety of high-quality technical ceramics. Perspectives and limitations of the LSD-print will be presented, with focus on achieving short debinding cycles and high productivity. T2 - MS&T CY - Pittsburgh, PA, USA DA - 06.10.2024 KW - Additive Manufacturing KW - Ceramic KW - Binder KW - Slurry KW - Water-based PY - 2024 AN - OPUS4-61882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker T1 - Advanced lightweight applications – recycling versus reliability and fossil energy footprint N2 - Advanced light weight applications like aircrafts and wind turbine blades are made of fibre reinforced plastics (FRP) with continuous fibre reinforcement and must withstand a high thermo-mechanical cyclic loading. The quality of the fibre matrix interface has a high impact on the fatigue life and was continuously improved over the years since the 50th. The fatigue life of glass fibre reinforced plastics (GFRP) used in aircraft industry is 10 to 100 times higher compared to glass fibre non crimp fabrics used for wind turbine blades. To assure a constant and reliable high quality and strength of reinforcement fibres, synthetic fibre production is state of the art (CF, GF). There is a need for recycling GFRP and CFRP waste due to the upcoming use. Pyrolysis and solvolysis are more expensive than the mechanical route however enable a more sustainable recycling. Natural fibres and recycled synthetic fibres have a high scatter in quality and strength. Hence it is a challenge to optimize the production / recycling processes to get a reliable quality for any demanding (second life) application. Chemical routes for using renewables resources and recycling, is going to be a good approach especially for polymer-matrix systems to get 100% quality (back) compared to the state of the art. Finally, a proper design, life-time extension and repair is preferable to recycling to keep the carbon footprint as low as possible. T2 - 27. INTERNATIONALES DRESDNER LEICHTBAUSYMPOSIUM CY - Dresden, Germany DA - 13.06.2024 KW - Polymer Matrix Composites KW - Carbon Fibre KW - Recycling KW - Circular Economy PY - 2024 UR - https://leichtbausymposium.de/deu/ AN - OPUS4-60683 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Langer, Carlotta A1 - Georgie, Yasmin Kim A1 - Porohovoj, Ilja A1 - Hafner, Verena Vanessa A1 - Ay, Nihat T1 - Analyzing Multimodal Integration in the Variational Autoencoder from an Information-Theoretic Perspective N2 - Human perception is inherently multimodal. We integrate, for instance, visual, proprioceptive and tactile information into one experience. Hence, multimodal learning is of importance for building robotic systems that aim at robustly interacting with the real world. One potential model that has been proposed for multimodal integration is the multimodal variational autoencoder. A variational autoencoder (VAE) consists of two networks, an encoder that maps the data to a stochastic latent space and a decoder that reconstruct this data from an element of this latent space. The multimodal VAE integrates inputs from different modalities at two points in time in the latent space and can thereby be used as a controller for a robotic agent. Here we use this architecture and introduce information-theoretic measures in order to analyze how important the integration of the different modalities are for the reconstruction of the input data. Therefore we calculate two different types of measures, the first type is called single modality error and assesses how important the information from a single modality is for the reconstruction of this modality or all modalities. Secondly, the measures named loss of precision calculate the impact that missing information from only one modality has on the reconstruction of this modality or the whole vector. The VAE is trained via the evidence lower bound, which can be written as a sum of two different terms, namely the reconstruction and the latent loss. The impact of the latent loss can be weighted via an additional variable, which has been introduced to combat posterior collapse. Here we train networks with four different weighting schedules and analyze them with respect to their capabilities for multimodal integration. KW - Multimodal Integration KW - Variational Autoencoder KW - Information Theory KW - Posterior Collapse PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616420 DO - https://doi.org/10.48550/arXiv.2411.00522 SP - 1 EP - 17 PB - Cornell University CY - Ithaca, NY AN - OPUS4-61642 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Ávila Calderón, Luis A1 - Schriever, Sina T1 - BAM Reference Data: Creep of Single-Crystal Ni-Based Superalloy CMSX-6 N2 - This publication provides comprehensive metadata and test results of constant force creep tests according to DIN EN ISO 204:2019-4 on the single crystal Ni-based superalloy CMSX-6 at T = 980 °C and initial stresses between 140 MPa and 230 MPa. The tests were carried out in an accredited test laboratory using calibrated measuring equipment. The data were audited and are BAM reference data. KW - NFDI-MatWerk KW - Digitalisierung KW - CMSX-6 KW - Creep KW - Reference Data KW - Referenzdaten KW - Ni-Based Superalloy PY - 2024 DO - https://doi.org/10.5281/zenodo.13937986 PB - Zenodo CY - Geneva AN - OPUS4-61649 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kuchenbecker, Petra T1 - Bestimmung der Skelettdichte mittels Gaspyknometrie N2 - Im Rahmen des 2. BAM-Akademie Info-Tages "Nano or not Nano" wurde die OECD TG 124 "Volume Specific Surface Area of Manufactured Nanomaterials" vorgestellt. Der Vortrag beschreibt detailliert das Messverfahren der He-Gaspyknometrie zur Bestimmung der Skelettdichte von Pulvern und geht auf Anwendbarkeit, Besonderheiten bei Nanopulvern und wichtige Einstellparameter für die Messung ein. T2 - BAM Akademie II: Info-Tage "Nano or not Nano" CY - Online meeting DA - 25.01.2024 KW - Pycnometry KW - Density KW - Nano powder PY - 2024 AN - OPUS4-59561 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lindemann, Franziska T1 - Bestimmung der spezifischen Oberfläche mittels Gasadsorption (BET-Verfahren) N2 - Im Rahmen des 2. BAM-Akademie Info-Tages "Nano or not Nano" wurde die OECD TG 124 "Volume Specific Surface Area of Manufactured Nanomaterials" vorgestellt. Der Vortrag beschreibt die Bestimmung der spezifischen Oberfläche von dispersen und/oder porösen Pulvern mittels Gasadsorption nach dem BET-Verfahren. Es wird auf die Anwendbarkeit der Methode eingegangen und es werden praktische Hinweise zur Probenvorbereitung und Messung von Nanomaterialien gegeben. T2 - BAM Akademie II: Info-Tage "Nano or not Nano" CY - Online meeting DA - 25.01.2024 KW - OECD TG 124 KW - Nanopulver KW - VSSA KW - Nano powder KW - BET KW - Spezifische Oberfläche PY - 2024 AN - OPUS4-59623 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -