@article{40557, abstract = {{Laser patterning of different precursor mixtures allows modulating the selectivity of iron oxide supported on N-doped carbons for ORR electrocatalysis.}}, author = {{Wang, Huize and Jerigova, Maria and Hou, Jing and Tarakina, Nadezda V. and Delacroix, Simon and Lopez Salas, Nieves and Strauss, Volker}}, issn = {{2050-7488}}, journal = {{Journal of Materials Chemistry A}}, keywords = {{General Materials Science, Renewable Energy, Sustainability and the Environment, General Chemistry}}, number = {{45}}, pages = {{24156--24166}}, publisher = {{Royal Society of Chemistry (RSC)}}, title = {{{Modulating between 2e− and 4e− pathways in the oxygen reduction reaction with laser-synthesized iron oxide-grafted nitrogen-doped carbon}}}, doi = {{10.1039/d2ta05838c}}, volume = {{10}}, 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{40559, author = {{Schulze Lammers, Bertram and Lopez Salas, Nieves and Stein Siena, Julya and Mirhosseini, Hossein and Yesilpinar, Damla and Heske, Julian and Kühne, Thomas D. and Fuchs, Harald and Antonietti, Markus and Mönig, Harry}}, issn = {{1936-0851}}, journal = {{ACS Nano}}, keywords = {{General Physics and Astronomy, General Engineering, General Materials Science}}, number = {{9}}, pages = {{14284--14296}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Real-Space Identification of Non-Noble Single Atomic Catalytic Sites within Metal-Coordinated Supramolecular Networks}}}, doi = {{10.1021/acsnano.2c04439}}, volume = {{16}}, year = {{2022}}, } @article{34700, author = {{Gharibian, Sevag and Santha, Miklos and Sikora, Jamie and Sundaram, Aarthi and Yirka, Justin}}, issn = {{1016-3328}}, journal = {{Computational Complexity}}, keywords = {{Computational Mathematics, Computational Theory and Mathematics, General Mathematics, Theoretical Computer Science}}, number = {{2}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Quantum generalizations of the polynomial hierarchy with applications to QMA(2)}}}, doi = {{10.1007/s00037-022-00231-8}}, volume = {{31}}, year = {{2022}}, } @article{35707, abstract = {{The proton conductivity of two coordination networks, [Mg(H2O)2(H3L)]·H2O and [Pb2(HL)]·H2O (H5L = (H2O3PCH2)2-NCH2-C6H4-SO3H), is investigated by AC impedance spectroscopy. Both materials contain the same phosphonato-sulfonate linker molecule, but have clearly different crystal structures, which has a strong effect on proton conductivity. In the Mg-based coordination network, dangling sulfonate groups are part of an extended hydrogen bonding network, facilitating a “proton hopping” with low activation energy; the material shows a moderate proton conductivity. In the Pb-based metal-organic framework, in contrast, no extended hydrogen bonding occurs, as the sulfonate groups coordinate to Pb2+, without forming hydrogen bonds; the proton conductivity is much lower in this material.}}, author = {{Javed, Ali and Steinke, Felix and Wöhlbrandt, Stephan and Bunzen, Hana and Stock, Norbert and Tiemann, Michael}}, issn = {{2190-4286}}, journal = {{Beilstein Journal of Nanotechnology}}, keywords = {{Electrical and Electronic Engineering, General Physics and Astronomy, General Materials Science}}, pages = {{437--443}}, publisher = {{Beilstein Institut}}, title = {{{The role of sulfonate groups and hydrogen bonding in the proton conductivity of two coordination networks}}}, doi = {{10.3762/bjnano.13.36}}, volume = {{13}}, year = {{2022}}, } @article{43158, abstract = {{In view of economic and ecological trends, the concepts for lightweight construction in transport systems are becoming increasingly important. These are frequently applied in the form of multi-material systems, which are characterized by the selective use of materials and geometries. One major challenge in the manufacturing of multi-material systems is the joining of the individual components to form a complete system. Mechanical joining processes such as semi-tubular self-piercing riveting are frequently used for this application but reach their limits concerning the number of combinations of geometry and material. In order to react to the requirements and to increase the versatility of semi-tubular self-pierce riveting, a process combination consisting of a tumbling process and a self-pierce riveting process has been presented previously. This process combination is used in this work to investigate the versatility and to identify the influencing parameters on it. For this purpose, experiments are conducted to identify process-side influence possibilities. The tests are performed with a dual-phase steel aluminum alloy to represent the varying mechanical characteristics of multi-material systems. Furthermore, the initial sheet thicknesses of the joining partners are varied in several steps. In addition to the geometric joint formation used to describe the undercut, the rivet head end position and the residual sheet thickness, the joining process, is also analyzed during the investigations. Further, the innovative joining process is evaluated by comparing it with a conventional self-piercing riveting process. The knowledge obtained represents a basis for the identification and evaluation of the versatility of the process combination.}}, author = {{Wituschek, Simon and Kappe, Fabian and Meschut, Gerson and Lechner, Michael}}, issn = {{1464-4207}}, journal = {{Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications}}, keywords = {{Mechanical Engineering, General Materials Science}}, publisher = {{SAGE Publications}}, title = {{{Geometric and mechanical joint characterization of conventionally and tumbled self-piercing riveting joints}}}, doi = {{10.1177/14644207221135400}}, year = {{2022}}, } @article{37711, abstract = {{AbstractPolarons influence decisively the performance of lithium niobate for optical applications. In this work, the formation of (defect) bound polarons in lithium niobate is studied by ab initio molecular dynamics. The calculations show a broad scatter of polaron formation times. Rising temperature increases the share of trajectories with long formation times, which leads to an overall increase of the average formation time with temperature. However, even at elevated temperatures, the average formation time does not exceed the value of 100 femtoseconds, i.e., a value close to the time measured for free, i.e., self-trapped polarons. Analyzing individual trajectories, it is found that the time required for the structural relaxation of the polarons depends sensitively on the excitation of the lithium niobate high-frequency phonon modes and their phase relation.}}, author = {{Krenz, Marvin and Gerstmann, Uwe and Schmidt, Wolf Gero}}, issn = {{0947-8396}}, journal = {{Applied Physics A}}, keywords = {{General Materials Science, General Chemistry}}, pages = {{480}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Bound polaron formation in lithium niobate from ab initio molecular dynamics}}}, doi = {{10.1007/s00339-022-05577-y}}, volume = {{128}}, year = {{2022}}, } @article{33724, author = {{Vieth, Pascal and Borgert, Thomas and Homberg, Werner and Grundmeier, Guido}}, issn = {{1438-1656}}, journal = {{Advanced Engineering Materials}}, keywords = {{Condensed Matter Physics, General Materials Science}}, publisher = {{Wiley}}, title = {{{Assessment of mechanical and optical properties of Al 6060 alloy particles by removal of contaminants}}}, doi = {{10.1002/adem.202201081}}, year = {{2022}}, } @article{34243, abstract = {{ In view of economic and ecological trends, the concepts for lightweight construction in transport systems are becoming increasingly important. These are frequently applied in the form of multi-material systems, which are characterized by the selective use of materials and geometries. One major challenge in the manufacturing of multi-material systems is the joining of the individual components to form a complete system. Mechanical joining processes such as semi-tubular self-piercing riveting are frequently used for this application but reach their limits concerning the number of combinations of geometry and material. In order to react to the requirements and to increase the versatility of semi-tubular self-pierce riveting, a process combination consisting of a tumbling process and a self-pierce riveting process has been presented previously. This process combination is used in this work to investigate the versatility and to identify the influencing parameters on it. For this purpose, experiments are conducted to identify process-side influence possibilities. The tests are performed with a dual-phase steel aluminum alloy to represent the varying mechanical characteristics of multi-material systems. Furthermore, the initial sheet thicknesses of the joining partners are varied in several steps. In addition to the geometric joint formation used to describe the undercut, the rivet head end position and the residual sheet thickness, the joining process, is also analyzed during the investigations. Further, the innovative joining process is evaluated by comparing it with a conventional self-piercing riveting process. The knowledge obtained represents a basis for the identification and evaluation of the versatility of the process combination. }}, author = {{Wituschek, Simon and Kappe, Fabian and Meschut, Gerson and Lechner, Michael}}, issn = {{1464-4207}}, journal = {{Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications}}, keywords = {{Mechanical Engineering, General Materials Science}}, publisher = {{SAGE Publications}}, title = {{{Geometric and mechanical joint characterization of conventionally and tumbled self-piercing riveting joints}}}, doi = {{10.1177/14644207221135400}}, year = {{2022}}, } @article{34242, author = {{Neuser, Moritz and Kappe, Fabian and Ostermeier, Jakob and Krüger, Jan Tobias and Bobbert, Mathias and Meschut, Gerson and Schaper, Mirko and Grydin, Olexandr}}, issn = {{1438-1656}}, journal = {{Advanced Engineering Materials}}, keywords = {{Condensed Matter Physics, General Materials Science}}, number = {{10}}, publisher = {{Wiley}}, title = {{{Mechanical Properties and Joinability of AlSi9 Alloy Manufactured by Twin‐Roll Casting}}}, doi = {{10.1002/adem.202200874}}, volume = {{24}}, year = {{2022}}, } @article{31360, abstract = {{The adaptive joining process employing friction-spun joint connectors (FSJC) is a promising method for the realization of adaptable joints and thus for lightweight construction. In addition to experimental investigations, numerical studies are indispensable tools for its development. Therefore, this paper includes an analysis of boundary conditions for the spatial discretization and mesh modeling techniques, the material modeling, the contact and friction modeling, and the thermal boundary conditions for the finite element (FE) modeling of this joining process. For these investigations, two FE models corresponding to the two process steps were set up and compared with the two related processes of friction stir welding and friction drilling. Regarding the spatial discretization, the Lagrangian approach is not sufficient to represent the deformation that occurs. The Johnson-Cook model is well suited as a material model. The modeling of the contact detection and friction are important research subjects. Coulomb’s law of friction is not adequate to account for the complex friction phenomena of the adaptive joining process. The thermal boundary conditions play a decisive role in heat generation and thus in the material flow of the process. It is advisable to use temperature-dependent parameters and to investigate in detail the influence of radiation in the entire process.}}, author = {{Oesterwinter, Annika and Wischer, Christian and Homberg, Werner}}, issn = {{2075-4701}}, journal = {{Metals}}, keywords = {{General Materials Science, Metals and Alloys}}, number = {{5}}, publisher = {{MDPI AG}}, title = {{{Identification of Requirements for FE Modeling of an Adaptive Joining Technology Employing Friction-Spun Joint Connectors (FSJC)}}}, doi = {{10.3390/met12050869}}, volume = {{12}}, 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{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{41485, author = {{Clemens, Robin and Barth, Enrico and Uhlmann, Eckart and Zhan, Yingjie and Caylak, Ismail and Mahnken, Rolf}}, issn = {{1556-5068}}, journal = {{SSRN Electronic Journal}}, keywords = {{General Earth and Planetary Sciences, General Environmental Science}}, publisher = {{Elsevier BV}}, title = {{{Effects on Process Forces of Individual Milling Tool Edges Depending on the Cutting Angle and Cutting Speed When Milling Cfrp}}}, doi = {{10.2139/ssrn.4259246}}, year = {{2022}}, } @article{37681, author = {{Moritz, Dominik Christian and Ruiz Alvarado, Isaac Azahel and Zare Pour, Mohammad Amin and Paszuk, Agnieszka and Frieß, Tilo and Runge, Erich and Hofmann, Jan P. and Hannappel, Thomas and Schmidt, Wolf Gero and Jaegermann, Wolfram}}, issn = {{1944-8244}}, journal = {{ACS Applied Materials & Interfaces}}, keywords = {{General Materials Science}}, number = {{41}}, pages = {{47255--47261}}, publisher = {{American Chemical Society (ACS)}}, title = {{{P-Terminated InP (001) Surfaces: Surface Band Bending and Reactivity to Water}}}, doi = {{10.1021/acsami.2c13352}}, volume = {{14}}, year = {{2022}}, } @article{34244, author = {{Kappe, Fabian and Zirngibl, Christoph and Schleich, Benjamin and Bobbert, Mathias and Wartzack, Sandro and Meschut, Gerson}}, issn = {{1526-6125}}, journal = {{Journal of Manufacturing Processes}}, keywords = {{Industrial and Manufacturing Engineering, Management Science and Operations Research, Strategy and Management}}, pages = {{1438--1448}}, publisher = {{Elsevier BV}}, title = {{{Determining the influence of different process parameters on the versatile self-piercing riveting process using numerical methods}}}, doi = {{10.1016/j.jmapro.2022.11.019}}, volume = {{84}}, 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}}, } @article{33801, author = {{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 = {{{New low order Runge–Kutta schemes for asymptotically exact global error estimation of embedded methods without order reduction}}}, doi = {{10.1016/j.cma.2022.115553}}, volume = {{401}}, year = {{2022}}, } @article{32412, abstract = {{Friction-spinning as an innovative incremental forming process enables large degrees of deformation in the field of tube and sheet metal forming due to a self-induced heat generation in the forming zone. This paper presents a new tool and process design with a driven tool for the targeted adjustment of residual stress distributions in the friction-spinning process. Locally adapted residual stress depth distributions are intended to improve the functionality of the friction-spinning workpieces, e.g. by delaying failure or triggering it in a defined way. The new process designs with the driven tool and a subsequent flow-forming operation are investigated regarding the influence on the residual stress depth distributions compared to those of standard friction-spinning process. Residual stress depth distributions are measured with the incremental hole-drilling method. The workpieces (tubular part with a flange) are manufactured using heat-treatable 3.3206 (EN-AW 6060 T6) tubular profiles. It is shown that the residual stress depth distributions change significantly due to the new process designs, which offers new potentials for the targeted adjustment of residual stresses that serve to improve the workpiece properties.}}, author = {{Dahms, Frederik and Homberg, Werner}}, issn = {{1662-9795}}, journal = {{Key Engineering Materials}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, location = {{Braga, Portugal}}, pages = {{683--689}}, publisher = {{Trans Tech Publications, Ltd.}}, title = {{{Manufacture of Defined Residual Stress Distributions in the Friction-Spinning Process: Driven Tool and Subsequent Flow-Forming}}}, doi = {{10.4028/p-3rk19y}}, volume = {{926}}, year = {{2022}}, }