@article{52613, abstract = {{During resistance spot welding of zinc-coated advanced high-strength steels (AHSSs) for automotive production, liquid metal embrittlement (LME) cracking may occur in the event of a combination of various unfavorable influences. In this study, the interactions of different welding current levels and weld times on the tendency for LME cracking in third-generation AHSSs were investigated. LME manifested itself as high-penetration cracks around the circumference of the spot welds for welding currents closely below the expulsion limit. At the same time, the observed tendency for LME cracking showed no direct correlation with the overall heat input of the investigated welding processes. To identify a reliable indicator of the tendency for LME cracking, the local strain rate at the origin of the observed cracks was analyzed over the course of the welding process via finite element simulation. While the local strain rate showed a good correlation with the process-specific LME cracking tendency, it was difficult to interpret due to its discontinuous course. Therefore, based on the experimental measurement of electrode displacement during welding, electrode indentation velocity was proposed as a descriptive indicator for quantifying cracking tendency.}}, author = {{Böhne, Christoph and Meschut, Gerson and BIEGLER, MAX and RETHMEIER, MICHAEL}}, issn = {{0043-2296}}, journal = {{Welding Journal}}, keywords = {{Metals and Alloys, Mechanical Engineering, Mechanics of Materials}}, number = {{7}}, pages = {{197--207}}, publisher = {{American Welding Society}}, title = {{{The Influence of Electrode Indentation Rate on LME Formation during RSW}}}, doi = {{10.29391/2022.101.015}}, volume = {{101}}, year = {{2022}}, } @article{34215, abstract = {{Clinching as a mechanical joining technique allows a fast and reliable joining of metal sheets in large-scale production. An efficient design and dimensioning of clinched joints requires a holistic understanding of the material, the joining process and the resulting properties of the joint. In this paper, the process chain for clinching metal sheets is described and experimental techniques are proposed to analyze the process-microstructure-property relationships from the sheet metal to the joined structure. At the example of clinching aluminum EN AW 6014, characterization methods are applied and discussed for the following characteristics: the mechanical properties of the sheet materials, the tribological behavior in the joining system, the joining process and the resulting material structure, the load-bearing behavior of the joint, the damage and degradation as well as the service life and crack growth behavior. The compilation of the characterization methods gives an overview on the advantages and weaknesses of the methods and the multiple interactions of material, process and properties during clinching. In addition, the results of the analyses on EN AW 6014 can be applied for parameterization and validation of simulations.}}, author = {{Kupfer, Robert and Köhler, Daniel and Römisch, David and Wituschek, Simon and Ewenz, Lars and Kalich, Jan and Weiß, Deborah and Sadeghian, Behdad and Busch, Matthias and Krüger, Jan Tobias and Neuser, Moritz and Grydin, Olexandr and Böhnke, Max and Bielak, Christian Roman and Troschitz, Juliane}}, issn = {{2666-3309}}, journal = {{Journal of Advanced Joining Processes}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Engineering (miscellaneous), Chemical Engineering (miscellaneous)}}, publisher = {{Elsevier BV}}, title = {{{Clinching of Aluminum Materials – Methods for the Continuous Characterization of Process, Microstructure and Properties}}}, doi = {{10.1016/j.jajp.2022.100108}}, volume = {{5}}, year = {{2022}}, } @article{53084, abstract = {{AbstractThe thermal decomposition of Zr(acac)4 is studied in a SiC-microreactor on the micro-second time scale. By utilizing synchrotron radiation and photoelectron photoion coincidence spectroscopy, six important zirconium intermediates, as for instance Zr(C5H7O2)2(C5H6O2), and Zr(C5H6O2)2, are identified in the gas phase for the first time. The adiabatic ionization thresholds of intermediately formed zirconium species are estimated and the main products of their thermal decomposition, acetylacetone, acetylallene and acetone are characterized unambiguously and isomer-selectively. Based on all detected intermediates, we deduce the predominant pyrolysis pathways of the precursor in the temperature range from 400 to 900 K. Our findings are complemented by numerical simulations of the flow field in the microreactor, which show that the choice of dilution gas significantly influences the temperature profile and residence times in the microreactor, such that helium provides a more uniform flow field than argon and should preferentially be used. Graphical abstract Using a soft ionization method coupled to velocity map imaging (VMI), leads to valuable insights in the thermal decomposition of Zr(C5H7O2)4, used in the synthesis of functional nanomaterials and ceramic coatings. Thanks to the use of a microreactor, important gas}}, author = {{Grimm, Sebastian and Baik, Seung-Jin and Hemberger, Patrick and Kasper, Tina and Kempf, Andreas M. and Atakan, Burak}}, issn = {{0884-2914}}, journal = {{Journal of Materials Research}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, General Materials Science}}, number = {{9}}, pages = {{1558--1575}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Insights into the decomposition of zirconium acetylacetonate using synchrotron radiation: Routes to the formation of volatile Zr-intermediates}}}, doi = {{10.1557/s43578-022-00566-6}}, volume = {{37}}, year = {{2022}}, } @article{53083, abstract = {{AbstractThe decomposition and reduction of ferrocene, an important precursor for iron chemical vapor deposition and catalyst for nanotube synthesis, is investigated in the gas‐phase. Reactive intermediates are detected to understand the underlying chemistry by using a microreactor coupled to a synchrotron light source. Utilizing soft photoionization coupled with photoelectron‐photoion coincidence detection enables us to characterize exclusive intermediates isomer‐selectively. A reaction mechanism for the ferrocene decomposition is proposed, which proceeds as a two‐step process. Initially, the molecule decomposes in a homogeneous surface reaction at temperatures <900 K, leading to products such as cyclopentadiene and cyclopentadienyl radicals that are immediately released to the gas‐phase. At higher temperatures, ferrocene rapidly decomposes in the gas‐phase, losing two cyclopentadienyl radicals in conjunction with iron. The addition of hydrogen to the reaction mixture reduces the decomposition temperature, and changes the branching ratio of the products. This change is mainly attributed to the H‐addition of cyclopentadienyl radicals on the surface, which leads to a release of cyclopentadiene into the gas‐phase. On the surface, ligand fragments may also undergo a series of catalytic H‐losses leading most probably to a high carbon content in the film. Finally, Arrhenius parameters for both global reactions are presented.}}, author = {{Grimm, Sebastian and Hemberger, Patrick and Kasper, Tina and Atakan, Burak}}, issn = {{2196-7350}}, journal = {{Advanced Materials Interfaces}}, keywords = {{Mechanical Engineering, Mechanics of Materials}}, number = {{22}}, publisher = {{Wiley}}, title = {{{Mechanism and Kinetics of the Thermal Decomposition of Fe(C5H5)2 in Inert and Reductive Atmosphere: A Synchrotron‐Assisted Investigation in A Microreactor}}}, doi = {{10.1002/admi.202200192}}, volume = {{9}}, year = {{2022}}, } @article{50600, abstract = {{ In a case study approach, the paper traces how technological expectations have been influential in the creation of European institutions, R&D programmes and regulatory instruments and how they have contributed to processes of European integration. The first case study shows how the promises of a coming ‘Atomic Age’ have been mobilized to support the foundation of the European Atomic Energy Community and, thus, contributed to European integration in the post-WW2 era. The second case study analyses how the security stream within the EU’s framework programmes for R&D is shaped by the promise of ‘technosecurity’ and enacts the normative claim of the EU’s security integration in the post-Cold War era. The third case study analyses how the EU’s AI strategy and AI act articulates the vision of a ‘human-centric AI’ and how this vision is related to the EU’s current attempt to restore citizens’ trust in times of crisis.}}, author = {{Hälterlein, Jens}}, issn = {{2243-4690}}, journal = {{Science & Technology Studies}}, keywords = {{History and Philosophy of Science}}, number = {{2}}, pages = {{26--46}}, publisher = {{Science and Technology Studies}}, title = {{{Technological Expectations and the Making of Europe}}}, doi = {{10.23987/sts.110036}}, volume = {{36}}, year = {{2022}}, } @article{33002, abstract = {{Many mechanical material properties show a dependence on the strain rate, e.g. yield stress or elongation at fracture. The quantitative description of the material behavior under dynamic loading is of major importance for the evaluation of crash safety. This is carried out using numerical methods and requires characteristic values for the materials used. For the standardized determination of dynamic characteristic values in sheet metal materials, tensile tests performed according to the guideline from [1]. A particular challenge in dynamic tensile tests is the force measurement during the test. For this purpose, strain gauges are attached on each specimen, wired to the measuring equipment and calibrated. This is a common way to determine a force signal that is as low in vibration and as free of bending moments as possible. The preparation effort for the used strain gauges are enormous. For these reasons, an optical method to determine the force by strain measurement using DIC is presented. The experiments are carried out on a high speed tensile testing system. In combioantion with a 3D DIC high speed system for optical strain measurement. The elastic deformation of the specimen in the dynamometric section is measured using strain gauges and the optical method. The measured signals are then compared to validate the presented method. The investigations are conducted using the dual phase steel material HCT590X and the aluminum material EN AW-6014 T4. Strain rates of up to 240 s-1 are investigated.}}, author = {{Böhnke, Max and Unruh, Eduard and Sell, Stanislaw and Bobbert, Mathias and Hein, David and Meschut, Gerson}}, issn = {{1662-9795}}, journal = {{Key Engineering Materials}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, location = {{Braga, Portugal}}, pages = {{1564--1572}}, publisher = {{Trans Tech Publications, Ltd.}}, title = {{{Functionality Study of an Optical Measurement Concept for Local Force Signal Determination in High Strain Rate Tensile Tests}}}, doi = {{10.4028/p-wpuzyw}}, volume = {{926}}, year = {{2022}}, } @article{34459, author = {{Schmelzle, Lars and Striewe, Marius and Mergheim, Julia and Meschut, Gerson and Possart, Gunnar and Teutenberg, Dominik and Hein, David and Steinmann, Paul}}, issn = {{0169-4243}}, journal = {{Journal of Adhesion Science and Technology}}, keywords = {{Materials Chemistry, Surfaces, Coatings and Films, Surfaces and Interfaces, Mechanics of Materials, General Chemistry}}, title = {{{Testing, modelling, and parameter identification for adhesively bonded joints under the influence of temperature}}}, doi = {{10.1080/01694243.2022.2125714}}, year = {{2022}}, } @article{37138, abstract = {{AbstractAssuming that potential biases of Artificial Intelligence (AI)-based systems can be identified and controlled for (e.g., by providing high quality training data), employing such systems to augment human resource (HR)-decision makers in candidate selection provides an opportunity to make selection processes more objective. However, as the final hiring decision is likely to remain with humans, prevalent human biases could still cause discrimination. This work investigates the impact of an AI-based system’s candidate recommendations on humans’ hiring decisions and how this relation could be moderated by an Explainable AI (XAI) approach. We used a self-developed platform and conducted an online experiment with 194 participants. Our quantitative and qualitative findings suggest that the recommendations of an AI-based system can reduce discrimination against older and female candidates but appear to cause fewer selections of foreign-race candidates. Contrary to our expectations, the same XAI approach moderated these effects differently depending on the context.}}, author = {{Hofeditz, Lennart and Clausen, Sünje and Rieß, Alexander and Mirbabaie, Milad and Stieglitz, Stefan}}, issn = {{1019-6781}}, journal = {{Electronic Markets (ELMA)}}, keywords = {{Management of Technology and Innovation, Marketing, Computer Science Applications, Economics and Econometrics, Business and International Management}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Applying XAI to an AI-based system for candidate management to mitigate bias and discrimination in hiring}}}, doi = {{10.1007/s12525-022-00600-9}}, year = {{2022}}, } @article{30657, author = {{Henkes, Alexander and Wessels, Henning and Mahnken, Rolf}}, issn = {{0045-7825}}, journal = {{Computer Methods in Applied Mechanics and Engineering}}, keywords = {{Computer Science Applications, General Physics and Astronomy, Mechanical Engineering, Mechanics of Materials, Computational Mechanics}}, publisher = {{Elsevier BV}}, title = {{{Physics informed neural networks for continuum micromechanics}}}, doi = {{10.1016/j.cma.2022.114790}}, volume = {{393}}, year = {{2022}}, } @article{40558, author = {{Odziomek, Mateusz and Giusto, Paolo and Kossmann, Janina and Tarakina, Nadezda V. and Heske, Julian and Rivadeneira, Salvador M. and Keil, Waldemar and Schmidt, Claudia and Mazzanti, Stefano and Savateev, Oleksandr and Perdigón‐Toro, Lorena and Neher, Dieter and Kühne, Thomas D. and Antonietti, Markus and Lopez Salas, Nieves}}, issn = {{0935-9648}}, journal = {{Advanced Materials}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, number = {{40}}, publisher = {{Wiley}}, title = {{{“Red Carbon”: A Rediscovered Covalent Crystalline Semiconductor}}}, doi = {{10.1002/adma.202206405}}, volume = {{34}}, year = {{2022}}, } @article{40567, author = {{Jerigová, Mária and Heske, Julian and Kühne, ThomasD. and Tian, Zhihong and Tovar, Michael and Odziomek, Mateusz and Lopez Salas, Nieves}}, issn = {{2196-7350}}, journal = {{Advanced Materials Interfaces}}, keywords = {{Mechanical Engineering, Mechanics of Materials}}, publisher = {{Wiley}}, title = {{{C 1 N 1 Thin Films from Guanine Decomposition Fragments}}}, doi = {{10.1002/admi.202202061}}, year = {{2022}}, } @article{33685, abstract = {{In the spatial confinement of cylindrical mesopores with diameters of a few nanometers, water molecules experience restrictions in hydrogen bonding. This leads to a different behavior regarding the molecular orientational freedom (‘structure of water') compared to the bulk liquid state. In addition to the pore size, the behavior is also strongly affected by the strength of the pore wall-to-water interactions, that is, the pore wall polarity. In this work, this is studied both experimentally and theoretically. The surface polarity of mesoporous silica (SiO2) is modified by functionalization with trimethylsilyl moieties, resulting in a change from a hydrophilic (pristine) to a hydrophobic pore wall. The mesopore surface is characterized by N2 and H2O sorption experiments. Those results are combined with IR spectroscopy to investigate pore wall-to-water interactions leading to different structures of water in the mesopore. Furthermore, the water's structure is studied theoretically to gain deeper insight into the interfacial interactions. For this purpose, the structure of water is analyzed by pairing densities, coordination, and angular distributions with a novel adaptation of surface-specific sum-frequency generation calculation for pore environments.}}, author = {{Weinberger, Christian and Zysk, Frederik and Hartmann, Marc and Kaliannan, Naveen and Keil, Waldemar and Kühne, Thomas and Tiemann, Michael}}, issn = {{2196-7350}}, journal = {{Advanced Materials Interfaces}}, keywords = {{Mechanical Engineering, Mechanics of Materials}}, number = {{20}}, publisher = {{Wiley}}, title = {{{The Structure of Water in Silica Mesopores – Influence of the Pore Wall Polarity}}}, doi = {{10.1002/admi.202200245}}, volume = {{9}}, year = {{2022}}, } @article{34216, abstract = {{Mechanical joining technologies are increasingly used in multi-material lightweight constructions and offer opportunities to create versatile joining processes due to their low heat input, robustness to metallurgical incompatibilities and various process variants. They can be categorised into technologies which require an auxiliary joining element, or do not require an auxiliary joining element. A typical example for a mechanical joining process with auxiliary joining element is self-piercing riveting. A wide range of processes exist which are not requiring an auxiliary joining element. This allows both point-shaped (e.g., by clinching) and line-shaped (e.g., friction stir welding) joints to be produced. In order to achieve versatile processes, challenges exist in particular in the creation of intervention possibilities in the process and the understanding and handling of materials that are difficult to join, such as fiber reinforced plastics (FRP) or high-strength metals. In addition, predictive capability is required, which in particular requires accurate process simulation. Finally, the processes must be measured non-destructively in order to generate control variables in the process or to investigate the cause-effect relationship. This paper covers the state of the art in scientific research concerning mechanical joining and discusses future challenges on the way to versatile mechanical joining processes.}}, author = {{Meschut, Gerson and Merklein, M. and Brosius, A. and Drummer, D. and Fratini, L. and Füssel, U. and Gude, M. and Homberg, Werner and Martins, P.A.F. and Bobbert, Mathias and Lechner, M. and Kupfer, R. and Gröger, B. and Han, Daxin and Kalich, J. and Kappe, Fabian and Kleffel, T. and Köhler, D. and Kuball, C.-M. and Popp, J. and Römisch, D. and Troschitz, J. and Wischer, Christian and Wituschek, S. and Wolf, M.}}, issn = {{2666-3309}}, journal = {{Journal of Advanced Joining Processes}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Engineering (miscellaneous), Chemical Engineering (miscellaneous)}}, publisher = {{Elsevier BV}}, title = {{{Review on mechanical joining by plastic deformation}}}, doi = {{10.1016/j.jajp.2022.100113}}, volume = {{5}}, year = {{2022}}, } @article{32275, author = {{Meschut, G. and Merklein, M. and Brosius, A. and Drummer, D. and Fratini, L. and Füssel, U. and Gude, M. and Homberg, W. and Martins, P.A.F. and Bobbert, M. and Lechner, M. and Kupfer, R. and Gröger, B. and Han, D. and Kalich, J. and Kappe, F. and Kleffel, T. and Köhler, D. and Kuball, C.-M. and Popp, J. and Römisch, D. and Troschitz, J. and Wischer, C. and Wituschek, S. and Wolf, M.}}, issn = {{2666-3309}}, journal = {{Journal of Advanced Joining Processes}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Engineering (miscellaneous), Chemical Engineering (miscellaneous)}}, publisher = {{Elsevier BV}}, title = {{{Review on mechanical joining by plastic deformation}}}, doi = {{10.1016/j.jajp.2022.100113}}, volume = {{5}}, year = {{2022}}, } @article{37647, abstract = {{Mechanical joining processes are an essential part of modern lightweight construction. They permit materials of different types to be joined in a way that is suitable for the loads involved. These processes reach their limits, however, as soon as the boundary conditions change. In most cases, these elements are specially adapted to the joining point and cannot be used universally. Changes require cost-intensive adaptation of both the element and the process control, thus making production more complex. This results in high costs due to the increased number of auxiliary joining element variants required and reduces the economic efficiency of mechanical joining. One approach to overcoming this issue is the use of adaptive auxiliary joining elements formed by friction spinning. This article presents the current state of research on pre-hole-free joining with adaptive joining elements. The overall process chain is illustrated, explained and analyzed. Special attention is paid to demonstrating the feasibility of pre-hole-free joining with adaptive joining elements. The chosen mechanical parameters are subsequently listed. Finally, a comprehensive outlook of the future development potential is derived.}}, author = {{Wischer, Christian and Homberg, Werner}}, issn = {{1662-9795}}, journal = {{Key Engineering Materials}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, pages = {{1468--1478}}, publisher = {{Trans Tech Publications, Ltd.}}, title = {{{Further Development of an Adaptive Joining Technique Based on Friction Spinning to Produce Pre-Hole-Free Joints}}}, doi = {{10.4028/p-1n6741}}, volume = {{926}}, year = {{2022}}, } @article{34224, abstract = {{Crack growth in structures depends on the cyclic loads applied on it, such as mechanical, thermal and contact, as well as residual stresses, etc. To provide an accurate simulation of crack growth in structures, it is of high importance to integrate all kinds of loading situations in the simulations. Adapcrack3D is a simulation program that can accurately predict the propagation of cracks in real structures. However, until now, this three-dimensional program has only considered mechanical loads and static thermal loads. Therefore, the features of Adapcrack3D have been extended by including contact loading in crack growth simulations. The numerical simulation of crack propagation with Adapcrack3D is generally carried out using FE models of structures provided by the user. For simulating models with contact loading situations, Adapcrack3D has been updated to work with FE models containing multiple parts and necessary features such as coupling and surface interactions. Because Adapcrack3D uses the submodel technique for fracture mechanical evaluations, the architecture of the submodel is also modified to simulate models with contact definitions between the crack surfaces. This paper discusses the newly implemented attribute of the program with the help of illustrative examples. The results confirm that the contact simulation in Adapcrack3D is a major step in improving the functionality of the program.}}, author = {{Joy, Tintu David and Weiß, Deborah and Schramm, Britta and Kullmer, Gunter}}, issn = {{2076-3417}}, journal = {{Applied Sciences}}, keywords = {{Fluid Flow and Transfer Processes, Computer Science Applications, Process Chemistry and Technology, General Engineering, Instrumentation, General Materials Science}}, number = {{15}}, publisher = {{MDPI AG}}, title = {{{Further Development of 3D Crack Growth Simulation Program to Include Contact Loading Situations}}}, doi = {{10.3390/app12157557}}, volume = {{12}}, year = {{2022}}, } @article{34070, author = {{Schramm, Britta and Harzheim, Sven and Weiß, Deborah and Joy, Tintu David and Hofmann, Martin and Mergheim, Julia and Wallmersperger, Thomas}}, issn = {{2666-3309}}, journal = {{Journal of Advanced Joining Processes}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Engineering (miscellaneous), Chemical Engineering (miscellaneous)}}, publisher = {{Elsevier BV}}, title = {{{A Review on the Modeling of the Clinching Process Chain - Part III: Operational Phase}}}, doi = {{10.1016/j.jajp.2022.100135}}, year = {{2022}}, } @article{34246, author = {{Kullmer, Gunter and Weiß, Deborah and Schramm, Britta}}, issn = {{0013-7944}}, journal = {{Engineering Fracture Mechanics}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, publisher = {{Elsevier BV}}, title = {{{Development of a method for the separate measurement of the growth of internal crack tips by means of the potential drop method}}}, doi = {{10.1016/j.engfracmech.2022.108899}}, year = {{2022}}, } @article{44041, author = {{Ahmadov, A. I. and Nagiyev, Sh. M. and Aydin, C. and Tarverdiyeva, V. A. and Orujova, M. Sh. and Badalov, S. V.}}, issn = {{2190-5444}}, journal = {{The European Physical Journal Plus}}, keywords = {{General Physics and Astronomy, Fluid Flow and Transfer Processes}}, number = {{9}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Bound state solutions of Dirac equation: spin and pseudo-spin symmetry in the presence of the combined Manning–Rosen and Yukawa tensor potentials}}}, doi = {{10.1140/epjp/s13360-022-03255-9}}, volume = {{137}}, year = {{2022}}, } @article{32592, author = {{Ju, X. and Mahnken, Rolf and Xu, Y. and Liang, L.}}, issn = {{0045-7825}}, journal = {{Computer Methods in Applied Mechanics and Engineering}}, keywords = {{Computer Science Applications, General Physics and Astronomy, Mechanical Engineering, Mechanics of Materials, Computational Mechanics}}, publisher = {{Elsevier BV}}, title = {{{NTFA-enabled goal-oriented adaptive space–time finite elements for micro-heterogeneous elastoplasticity problems}}}, doi = {{10.1016/j.cma.2022.115199}}, volume = {{398}}, year = {{2022}}, }