@inproceedings{60615, author = {{Hermelingmeier, Lucas and Teutenberg, Dominik and Meschut, Gerson}}, booktitle = {{25. Kolloquium: Gemeinsame Forschung in der Klebtechnik}}, title = {{{Methodenentwicklung zur Ermittlung lokaler Klebschichtzustände innerhalb struktureller Verbindungen}}}, year = {{2025}}, } @inproceedings{64588, author = {{Neubert, Fynn Lucas and Teutenberg, Dominik and Meschut, Gerson and Rodschei, Maxim and Mergheim, Julia}}, booktitle = {{25. Kolloquium: Gemeinsame Forschung in der Klebtechnik}}, location = {{Köln}}, title = {{{Experimentelle und numerische Untersuchungen zur Alterung von Klebverbindungen unter zyklischer und hygrothermischer Beanspruchung im Stahl- und Anlagenbau}}}, year = {{2025}}, } @article{64591, abstract = {{Abstract Graph states are a fundamental class of multipartite entangled quantum states with wide-ranging applications in quantum information and computation. In this work, we develop a systematic approach for constructing and analyzing χ-colorable graph states, deriving explicit closed-form expressions for arbitrary χ. For a broad family of two- and three-colorable graph states, the representations obtained using only local operations require a minimal number of terms in the Z-eigenbasis. We prove that every two-colorable graph state is local Clifford (LC) equivalent to a state expressible as a summation of rows of an orthogonal array (OA). For graph states with χ > 2, we show that they are LC-equivalent to quantum OAs, establishing a direct combinatorial connection between multipartite entanglement and structured quantum states. Furthermore, the upper and lower bounds of the Schmidt measure for graph states with arbitrary χ colorability are discussed, extending the results for an arbitrary local dimension. Our results offer an efficient and practical method for systematically constructing graph states, optimizing their representation in quantum circuits, and identifying structured forms of multipartite entanglement. This approach also connects graph states to k-uniform and absolutely maximally entangled states, motivating further exploration of the structure of entangled states and their applications in quantum networks, quantum error correction, and measurement based quantum computing.}}, author = {{Revis, Konstantinos-Rafail and Zakaryan, Hrachya and Raissi, Zahra}}, issn = {{1751-8113}}, journal = {{Journal of Physics A: Mathematical and Theoretical}}, number = {{35}}, publisher = {{IOP Publishing}}, title = {{{χ-colorable graph states: closed-form expressions and quantum orthogonal arrays}}}, doi = {{10.1088/1751-8121/adfe45}}, volume = {{58}}, year = {{2025}}, } @article{63076, abstract = {{This paper develops a new concept and framework for understanding resilient digital democracy in an age defined by polarisation, cascading crises, and the global rise of digital authoritarianism. It begins by tracing the concept of resilience from systems theory to social and political life, showing that resilience in democracy is not a mechanical property of systems but a dynamic, human-driven practice grounded in agency, resistance, and collective self-determination. The paper argues that with emerging challenges in the digital sphere, such as misinformation, surveillance capitalism, platform monopolies, deepfakes, and hybrid warfare, democracy can only endure if its digital dimensions are protected and transformed. Building on this foundation, the paper introduces a holistic approach to resilient digital democracy that spans environmental, technological, economic, political, and cultural domains, and advances strategies such as public-commons digital infrastructures, platform co-operatives, public service Internet platforms, free/libre open source software (FLOSS), participatory innovations, and hybrid offline/online democratic practices. The result is a fresh, interdisciplinary vision of how democracy can be reinvented in the digital age.}}, author = {{Fuchs, Christian}}, issn = {{2732-5121}}, journal = {{Open Research Europe}}, publisher = {{F1000 Research Ltd}}, title = {{{What is and how do we Achieve a Resilient Digital Democracy?}}}, doi = {{10.12688/openreseurope.21988.2}}, volume = {{5}}, year = {{2025}}, } @inproceedings{64610, author = {{Hadipour, Amir Hossein and Jafari, Atousa and Awais, Muhammad and Platzner, Marco}}, booktitle = {{2025 IEEE 28th International Symposium on Design and Diagnostics of Electronic Circuits and Systems (DDECS)}}, publisher = {{IEEE}}, title = {{{A Two-Stage Approximation Methodology for Efficient DNN Hardware Implementation}}}, doi = {{10.1109/ddecs63720.2025.11006769}}, year = {{2025}}, } @article{59872, abstract = {{Lightweight design is a driving concept in modern automotive engineering to minimize resource consumption over a vehicle's lifecycle through multi-material design, which relies on the use of joining techniques in car body fabrication. Multi-material design and the increasing trend towards producing large structural components using the megacasting process pose considerable challenges, particularly in the mechanical joining of aluminium-silicon (AlSi) castings. These castings typically exhibit low ductility and are prone to cracking when mechanically joined. Based on the excellent castability of hypoeutectic AlSi alloys, these are applied in sand casting and die casting as well as in megacasting. With a silicon content between 7 wt% and 12 wt%, these AlSi-alloys have a plate-like silicon phase that initiates cracks during mechanical joining. To enhance the joinability of castings, the research hypothesis is that improved solidification conditions enable a significant modification in the microstructure and therefore, increase the mechanical properties. During the manufacture of the castings using the sand casting process, the solidification conditions within the structural elements are varied to modify the microstructure to obtain castings with graded microstructure. The castings are evaluated using mechanical, microstructural and joining testing methods and finally, a microstructure-joinability correlation is established.}}, author = {{Neuser, Moritz and Schlichter, Malte Christian and Hoyer, Kay-Peter and Bobbert, Mathias and Meschut, Gerson and Schaper, Mirko}}, journal = {{44th Conference of the International Deep Drawing Research Group (IDDRG 2025)}}, keywords = {{Joining, Casting, Self-pierce riveting, Aluminium casting alloy}}, location = {{Lissabon (Portugal)}}, title = {{{Mechanical joinability of microstructurally graded structural components manufactured from hypoeutectic aluminium casting alloys}}}, doi = {{10.1051/matecconf/202540801081}}, volume = {{408}}, year = {{2025}}, } @inproceedings{59878, abstract = {{Abstract. In the development of advanced lightweight automotive solutions, self-piercing riveting (SPR) offers the possibility of joining multi-material structures to fulfil a wide variety of requirements. With regard to the entire process chain, production-related pre-deformations of the parts to be joined can influence the geometric shape and load capacity of SPR joints. Various studies have investigated the influence of pre-stretched sheet materials, in the sense of pre-drawing processes, on the formation of SPR joints. The impact of pre-stretching sheet metals on the formation of their geometrical characteristics and the shear-tensile strength of SPR processes was observed [1]. Pre-rolled semi-finished products are also joined together in mixed material automotive structures, e.g. tailor rolled blanks. This work aims to investigate the influence of pre-rolled joining parts on the geometric formation and load-carrying capacity of SPR joints. For this purpose, sheets of metal are cold-formed using a rolling process to induce a defined strain-hardening state in the material and then joined in various combinations. As the degree of deformation increases, the rolling of samples can lead to minimal accumulation of damage in the sheet materials, which can influence the joint behaviour. The rolling process, as well as the subsequent joining process, are also investigated by FEM. The influence of pre-rolled semi-finished products on the strength of the SPR joints is investigated.}}, author = {{Schlichter, Malte Christian and Harabati, Özcan and Ludwig, Jean-Patrick and Böhnke, Max and Bielak, Christian Roman and Bobbert, Mathias and Meschut, Gerson}}, booktitle = {{Materials Research Proceedings}}, issn = {{2474-395X}}, publisher = {{Materials Research Forum LLC}}, title = {{{Experimental and numerical investigation of the influence of rolling-induced sheet metal deformation on SPR joints}}}, doi = {{10.21741/9781644903599-148}}, volume = {{54}}, year = {{2025}}, } @inproceedings{60977, abstract = {{In the development of advanced lightweight automotive solutions, self-piercing riveting (SPR) offers the possibility of joining multi-material structures to fulfil a wide variety of requirements. With regard to the entire process chain, production-related pre-deformations of the parts to be joined can influence the geometric shape and load capacity of SPR joints. Various studies have investigated the influence of pre-stretched sheet materials, in the sense of pre-drawing processes, on the formation of SPR joints. The impact of pre-stretching sheet metals on the formation of their geometrical characteristics and the shear-tensile strength of SPR processes was observed [1]. Pre-rolled semi-finished products are also joined together in mixed material automotive structures, e.g. tailor rolled blanks. This work aims to investigate the influence of pre-rolled joining parts on the geometric formation and load-carrying capacity of SPR joints. For this purpose, sheets of metal are cold-formed using a rolling process to induce a defined strain-hardening state in the material and then joined in various combinations. As the degree of deformation increases, the rolling of samples can lead to minimal accumulation of damage in the sheet materials, which can influence the joint behaviour. The rolling process, as well as the subsequent joining process, are also investigated by FEM. The influence of pre-rolled semi-finished products on the strength of the SPR joints is investigated.}}, author = {{Schlichter, Malte Christian and Harabati, Özcan and Ludwig, Jean-Patrick and Böhnke, Max and Bielak, Christian Roman and Bobbert, Mathias and Meschut, Gerson}}, booktitle = {{Materials Research Proceedings}}, issn = {{2474-395X}}, publisher = {{Materials Research Forum LLC}}, title = {{{Experimental and numerical investigation of the influence of rolling-induced sheet metal deformation on SPR joints}}}, doi = {{10.21741/9781644903599-148}}, volume = {{54}}, year = {{2025}}, } @inproceedings{60978, abstract = {{The present study is an experimental analysis of the influence of pre-forming on the failure behaviour of clinched specimens under quasi-static and cyclic loading conditions. In this context, the geometric formation of the clinched joints is taken into account, with regard to the loading behaviour. The study also includes a comparison of the failure behaviour of quasi-static and cyclic tested specimen. Testing is done on non-pre-deformed and pre-deformed specimens. For this purpose, experimental investigations are carried out on two material combinations consisting of HCT590X steel sheet and EN AW-6014 T4 aluminium sheet. The focus is on the fatigue analysis of the clinched joints. The aim is to identify the failure modes under cyclic loading and the crack formation with regard to forming operations prior to the joining process. The investigations show that the cyclic load-bearing behaviour of the HCT590X joints is reduced by introducing a plastic pre-deformation of the to be joined parts.}}, author = {{Schlichter, Malte Christian and Harabati, Özcan and Böhnke, Max and Bielak, Christian Roman and Bobbert, Mathias and Meschut, Gerson}}, booktitle = {{Materials Research Proceedings}}, issn = {{2474-395X}}, publisher = {{Materials Research Forum LLC}}, title = {{{Investigation on manufacturing-induced pre-deformation on the fatigue behaviour of clinched joints}}}, doi = {{10.21741/9781644903551-16}}, volume = {{52}}, year = {{2025}}, } @inproceedings{59587, abstract = {{Abstract. As a widely used sheet metal in clinched joints within the automotive industry, the aluminum alloy EN AW-6014 has been the focus of numerous studies. High-cycle fatigue (HCF) is a critical aspect when assessing the durability of clinched joints. In the present work, the HCF behavior of EN AW-6014 T4 was explored both experimentally and numerically. To model the fatigue behavior, Lemaitre’s two-scale damage model was used. Two key parameters, damage strength and damage exponent, are necessary for numerical investigations of HCF behavior. These parameters were determined through experiments with flat specimens and subsequently validated within a numerical model of clinched joints. The numerical results for fatigue match the experimental ones of the clinched joints quite well.}}, author = {{Chen, Chin and Schlichter, Malte Christian and Harzheim, Sven and Hofmann, Martin and Bobbert, Mathias and Meschut, Gerson and Wallmersperger, Thomas}}, booktitle = {{Materials Research Proceedings}}, issn = {{2474-395X}}, publisher = {{Materials Research Forum LLC}}, title = {{{High-cycle fatigue testing and parameter identification for numerical simulation of aluminum alloy EN AW-6014}}}, doi = {{10.21741/9781644903551-23}}, volume = {{52}}, year = {{2025}}, } @inproceedings{60002, abstract = {{This study focuses on damage modeling across different mechanical joining processes within a process chain, specifically using clinching and self-pierce riveting (SPR). The aim is to apply a comprehensive model that captures the damage mechanisms and interactions in these technologies, optimizing them for enhanced performance and durability of aluminum joints. A GISSMO damage model was utilized, based on the stress states occurring during the joining process and a newly introduced damage testing method. This model was applied to both clinching and SPR processes. A detailed analysis of the stress states provided insights into their effect on the material. By incorporating these insights into the GISSMO model, improved accuracy in damage prediction was achieved. The model's application to clinching and SPR demonstrated its effectiveness in optimizing aluminum joint performance and durability, ensuring that the processes can be finely tuned to minimize damage and enhance joint quality.}}, author = {{Harabati, Özcan and Bielak, Christian Roman and Böhnke, Max and Schlichter, Malte Christian and Brockmeier, Marc and Bobbert, Mathias and Meschut, Gerson}}, booktitle = {{Materials Research Proceedings}}, issn = {{2474-395X}}, publisher = {{Materials Research Forum LLC}}, title = {{{Cross-process damage modeling: A process-chain case study of clinching and self-pierced riveting for aluminum connections}}}, doi = {{10.21741/9781644903551-19}}, volume = {{52}}, year = {{2025}}, } @article{59584, author = {{Friedlein, Johannes and Lüder, Stephan and Kalich, Jan and Schmale, Hans Christian and Böhnke, Max and Schlichter, Malte Christian and Bobbert, Mathias and Meschut, Gerson and Steinmann, Paul and Mergheim, Julia}}, issn = {{2666-3309}}, journal = {{Journal of Advanced Joining Processes}}, publisher = {{Elsevier BV}}, title = {{{Application of stress-state-dependent ductile damage and failure model to clinch joining for a wide range of tool and material combinations}}}, doi = {{10.1016/j.jajp.2025.100299}}, volume = {{11}}, year = {{2025}}, } @inproceedings{64616, abstract = {{The circular economy offers decisive advantages over the currently prevalent linear economy in industry. Firstly, the reuse of products, individual parts and material reduces the need for new production or generation and the associated consumption of energy and resources. Secondly, it helps to avoid the generation of waste. Early consideration of circular economic principles in product development processes is essential to specifically promote reuse, reparability and recycling. Efficient recycling of assemblies requires well-defined strategies. However, various challenges hinder the efficiency of technical recycling processes in industrial applications. This paper presents an Ishikawa (fishbone) diagram-based approach to systematically identify and categorize these influences. The method is implemented within an industrial framework, highlighting key obstacles such as material composition, design constraints, use of technology, framework conditions, economic limitations and regulatory challenges. By applying a scenario analysis, this approach examines potential future developments and their impact on recycling-oriented design choices. This helps to identify critical influencing factors and supports the development of resilient and sustainable industrial practices. This framework will serve as the foundation for developing an automated approach to circular design, enabling industries to more effectively integrate sustainability into their processes and adapt to changing environmental demands.}}, author = {{Rohde, Katharina and Gonzalez, Barbara Fernandez and Budde, Finn Lukas and Ott, Manuel and Mozgova, Iryna and Mendibe, Alain Alonso}}, booktitle = {{Safe and Sustainable Value Creation by Design - Proceedings of the 21st Global Conference on Sustainable Manufacturing}}, editor = {{Kohl, Holger and Seliger, Günther and Dietrich, Franz and Campana, Giampaolo}}, location = {{Bologna, Italy}}, publisher = {{Springer Nature Switzerland AG}}, title = {{{Unveiling Barriers to Recycling with a Focus on Design: An Ishikawa Diagram-Based Approach with Industrial Application}}}, volume = {{1}}, year = {{2025}}, } @inproceedings{60440, abstract = {{The versatile self-pierce riveting (V-SPR) is a further development of semi-tubular self-pierce riveting. V-SPR enables adaptation to changing boundary conditions, such as a change in the material thickness combination, without varying the rivet die combination due to increased punch actuation and the use of multi-range capable rivets [1]. The inner punch first sets the rivet. The outer punch then forms the rivet head to the respective sheet thickness. For this, the rivet requires a hard shank and a ductile rivet head, which is achieved by an inductive local hardening process [2]. Until now, the joint formation of rivets with graded hardness profile has been challenging to estimate in the FEM simulation due to the inhomogeneous material conditions in the rivet. In this study, a method capable of reproducing the experimentally determined hardness levels of rivets in detail is shown. This FE model enables the realistic modelling of the mechanical properties of the rivet on the basis of the hardness profile in order to predict the correct deformation processes and stresses during the riveting process. First, the detailed experimental hardness mapping of the locally heat-treated rivets is transferred into the FE model. The FEM material model can predict the local strength of the rivet based on hardness by scaling the flow curves. To estimate the predictive capability of the FEM model, the joint formation of rivets with different graded hardness profiles is compared experimentally and simulative. Based on the validated model, the influence of different rivet hardness profiles on the joint formation is analysed numerically. By adapting the material model, a high level of correlation between the experiment's joint formation and the simulation can be achieved.}}, author = {{Holtkamp, Pia Katharina and Bielak, Christian Roman and Bobbert, Mathias and Meschut, Gerson}}, booktitle = {{Materials Research Proceedings}}, issn = {{2474-395X}}, publisher = {{Materials Research Forum LLC}}, title = {{{Simulation of the joining process of graded hardened multi-range capable rivets}}}, doi = {{10.21741/9781644903599-153}}, volume = {{54}}, year = {{2025}}, } @inproceedings{64562, abstract = {{Für das Verständnis und die Weiterentwicklung temperaturgestützter mechanischer Fü-geprozesse mit thermoplastischen Faser-Kunststoff-Verbunden (FKV) ist die zerstörungsfreie Analyse der Materialstruktur im Inneren des Fügepunktes während der Entstehung und Belastung erforderlich. Die Kombination aus Prüfung unter Temperatureinfluss und in situ Computertomographie (CT) eröffnet neue Möglichkeiten für die Fügeprozessanalyse. Dazu wurde dazu eine Thermokammer entwickelt und in eine bestehende in situ CT-Anlage integriert. Anwendungsszenarien sind die Herstellung und Prüfung von Fügepunkten unter Temperatur. Die Erwärmung erfolgt über einzeln regelbare Heizzonen, welche eine gezielte Temperaturführung über die gesamte Probengeometrie ermöglichen. Die Temperaturkurve eines Aufheizversuchs, sowie eine Röntgenprojektion einer Probe innerhalb der Thermokammer validie-ren die Konstruktion.}}, author = {{Dargel, Alrik and Köhler, Daniel and Gude, Maik and Kupfer, Robert}}, booktitle = {{Tagungsband 43. Vortrags- und Diskussionstagung Werkstoffprüfung 2025}}, editor = {{Zimmermann, Martina}}, isbn = {{978-3-88355-454-9}}, keywords = {{in situ CT, Thermokammer, Thermoplastische FKV}}, location = {{Dresden}}, pages = {{165--170}}, publisher = {{Deutsche Gesellschaft für Materialkunde e.V. (DGM)}}, title = {{{In situ CT unter Temperatur: Thermokammer für thermoplastische FKV-Fügeprozesse}}}, volume = {{43}}, year = {{2025}}, } @article{61767, abstract = {{Abstract A clinch point’s quality is usually assessed using ex situ destructive testing methods. These, however, are unable to detect phenomena immediately during the joining process. For instance, elastic deformations reverse and cracks close after unloading. In situ methods such as the force-displacement evaluation are used to investigate a clinching process, though deviations in the clinch point geometry cannot be derived with this method. To overcome these limitations, the clinching process can be investigated using in situ computed tomography (in situ CT). When investigating the clinching of aluminum parts in in situ CT, the sheet-sheet interface is hardly visible. Earlier investigations showed that radiopaque materials can be applied between the joining parts to enhance the detectability of the sheet-sheet interface. However, the layers cause strong artefacts, break during the clinching process or change the clinch joint’s properties significantly. In this paper, a minimally invasive method to enhance the interface detectability is presented. First, the aluminum oxide layer is removed by etching. Second, the specimen is electroplated with copper or gold, respectively. In some cases, a mask is applied to create a cross-shaped plating pattern. Then, the plated specimen is clinched with a non-plated counterpart and the interface detectability of the clinch points is assessed in CT scans. It is shown that a copper plating of 2.6–4 μm can visualize some parts of the interface, while 7–9 μm is suitable to enhance the detectability of the sheet-sheet interface almost continuously.}}, author = {{Köhler, Daniel and Dargel, Alrik and Troschitz, Juliane and Gude, Maik and Kupfer, Robert}}, issn = {{0195-9298}}, journal = {{Journal of Nondestructive Evaluation}}, number = {{4}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{In Situ CT of Clinch Points – Enhancing Interface Detectability Using Electroplated Patterns of Radiopaque Materials}}}, doi = {{10.1007/s10921-025-01270-1}}, volume = {{44}}, year = {{2025}}, } @article{61161, abstract = {{Abstract The effects of corrosion on clinched joints are not completely understood yet. Recent research indicates that galvanic corrosion can actually enhance the fatigue life of clinched joints. It is then of significant interest to investigate the effects of another corrosion phenomenon, pitting corrosion, on the fatigue behavior of clinched joints. Pitting corrosion occurs in passive metals and can lead to stress concentrations. In the present study, the effects of pitting corrosion are investigated by using Lemaitre’s two-scale fatigue model with a 2D geometry of clinched joints. A slip condition is applied as a boundary condition to simplify the clinched joint model and reduce the computational cost of solving the contact mechanics problem. Additionally, a method to determine the damage strength and the damage exponent used in the two-scale damage model is introduced. Numerical simulations reveal that pitting corrosion reduces the fatigue life of clinched joints, particularly when it occurs on the internal surface in the neck area.}}, author = {{Chen, Chin and Harzheim, Sven and Hofmann, Martin and Wallmersperger, Thomas}}, issn = {{0001-5970}}, journal = {{Acta Mechanica}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Numerical investigation of the effects of pitting corrosion on high-cycle fatigue of clinched joints}}}, doi = {{10.1007/s00707-025-04234-8}}, year = {{2025}}, } @article{61411, abstract = {{Abstract The effect of corrosion on mechanically joined components is not well understood. While recent research shows that a brief exposure of clinched specimens to a salt spray environment improves the specimens’ fatigue life, other research shows a decrease in load bearing capabilities with increasing corrosion times. These studies primarily focus on galvanic corrosion. It is not entirely clear how other corrosion phenomena, such as pitting corrosion, affect the fatigue life of clinched joints. In this work, a numerical model is used, which is able to simulate corrosion pit growth in EN AW-6014. The experimental polarization data of EN AW-6014 are used directly in the calculation of the interface kinetics parameter of the model.}}, author = {{Harzheim, Sven and Chen, Chin and Hollmer, Katharina and Hofmann, Martin and Zimmermann, Martina and Wallmersperger, Thomas}}, issn = {{0001-5970}}, journal = {{Acta Mechanica}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Numerical investigation of pitting corrosion in clinched joints}}}, doi = {{10.1007/s00707-025-04248-2}}, year = {{2025}}, } @inproceedings{59783, author = {{Mauro, D. A. and Ludovico, L. A. and Aydin, H. H. and Berndt, Axel and Grothe, T.}}, booktitle = {{AM.ICAD: Audio Mostly & ICAD Joint Conf.}}, publisher = {{ACM}}, title = {{{Detmold musical Instrument Timbre Explorer (DmITE): Interactive visualization of musical instruments radiation pattern using IEEE 1599}}}, year = {{2025}}, } @inproceedings{59748, author = {{Grothe, T. and Aydin, H. B. and Mauro, D. A. and Ludovico, L. A. and Berndt, Axel}}, booktitle = {{DAS/DAGA 2025 – 51st Annual Meeting on Acoustics}}, title = {{{Detmold interactive Musical Instrument Timbre Explorer (DmITE) - a web application for experimental learning in musical acoustics}}}, year = {{2025}}, }