@inproceedings{64129,
abstract = {{Selecting scan angles such that surface segments are aligned with straight X-ray paths (i.e., rays are tangential to the surface and therefore perpendicular to the local surface normal) is known to produce sharper transitions of those surface segments in the reconstructed volume. This enhances dimensional accuracy in sparse-view computed tomography (CT). However, existing approaches offer no direct means to exploit this criterion for automatic scan-angle optimization. We propose a method that uses a virtual representation of the CT setup, including an STL surface model of the inspected part, to automatically identify taskspecific scan angles. Using elementary vector calculus, the algorithm determines projection directions that generate tangential X-rays for targeted surface segments. To support different levels of geometric complexity, we introduce two variants of the angle-selection procedure. The methods were experimentally validated on two objects with distinct absorption and geometric characteristics. For a steel gauge block, employing the minimum number of task-specific projections required for surface-data completeness substantially outperformed a conventional high-projection scan. For a geometrically more complex test object, surface-related errors were still reduced within the region of interest. The proposed approach – particularly suited for flat surface structures and not accounting for image-degrading factors other than cone-beam artifacts – shows promise for high-throughput dimensional metrology of mono-material parts.}},
author = {{Butzhammer, Lorenz and Braun, Matthias Robert Oskar and Herath, Colin and Hausotte, Tino}},
booktitle = {{e-Journal of Nondestructive Testing}},
issn = {{1435-4934}},
location = {{Linz}},
number = {{3}},
publisher = {{NDT.net GmbH & Co. KG}},
title = {{{Higher accuracy with fewer projections? Automated scan angle selection for dimensional Computed Tomography based on a simple data completeness measure for the part surface}}},
doi = {{10.58286/32560}},
volume = {{31}},
year = {{2026}},
}
@article{64251,
abstract = {{ABSTRACT
Clinching is a widely adopted joining technique in the automotive industry, enabling the fabrication of lightweight structures from dissimilar sheet materials. Accurate prediction of the fatigue life of clinched joints is essential for ensuring structural safety and minimizing development costs. However, full 3D fatigue simulations over millions of cycles are computationally intensive due to the complexity of contact mechanics. This study introduces a 2D numerical model that circumvents direct contact modeling by applying a slip condition at the sheet interface, significantly reducing computational demands. A micro‐slip friction model is used to represent the mechanical interface behavior, while a two‐scale damage model captures the fatigue damage evolution. The model is validated against experimental data and used to investigate the influence of friction coefficient and tangential contact stiffness on fatigue life, highlighting its efficiency and predictive capability.}},
author = {{Chen, Chin and Hofmann, Martin and Wallmersperger, Thomas}},
issn = {{1617-7061}},
journal = {{PAMM}},
number = {{1}},
publisher = {{Wiley}},
title = {{{A 2D Approach to Predict the High‐Cycle Fatigue Life of Clinched Joints}}},
doi = {{10.1002/pamm.70035}},
volume = {{26}},
year = {{2026}},
}
@article{64250,
abstract = {{Abstract
Salt-spray testing is widely used in the automotive and materials industries to assess the corrosion resistance of protective coatings, where uniform corrosion is a key indicator of material performance. This work presents a numerical uniform corrosion model that predicts the corrosion rate of hot-dip zinc in salt-spray environments by incorporating electrochemical reactions, mass transport via the Nernst–Planck equation, and ionic-strength effects through the Brønsted–Bjerrum relation. The model is calibrated using immersion-test data and extended to account for electrolyte layer growth, droplet deposition, and periodic run-off in salt-spray environments. The calibration establishes a relationship between the porosity of the zinc oxide layer and the rate constant of zinc oxide precipitation. The validated model reproduces the transition from activation- to diffusion-controlled corrosion and captures the experimentally observed corrosion kinetics with an error margin of 20% when electrolyte renewal is included. The results highlight the decisive role of electrolyte dynamics in salt-spray environments and provide a foundation for extending the framework to more complex cyclic corrosion tests.}},
author = {{Chen, Chin and Hofmann, Martin and Wallmersperger, Thomas}},
issn = {{2397-2106}},
journal = {{npj Materials Degradation}},
publisher = {{Springer Science and Business Media LLC}},
title = {{{Modeling the uniform corrosion behavior of zinc in salt spray testing}}},
doi = {{10.1038/s41529-026-00749-0}},
year = {{2026}},
}
@article{64678,
abstract = {{One of the major topics in the modern automotive industry is reducing emissions and increasing the mileage
range. To tackle this challenge, on the one hand, modifying the powertrain system is a possibility, and on the
other hand, lightweight design offers various possibilities. Multi-Material Design (MMD) involves designing car
bodies that combine different materials that require joining. Given the variety of materials, mechanical joining
processes are preferred. Especially the current development of the Giga/Mega-casting process concerning
aluminium casting and the subsequent mechanical joining illustrates the challenges of this material group. In car
production, aluminium castings are mainly made from aluminium-silicon (AlSi) alloys. Ultimately, the alloy
system's insufficient ductility leads to crack initiation during mechanical joining. Cast parts are therefore often
used in areas of the car body that are exposed to high-pressure loads. For example, self-piercing riveting (SPR) is
used due to its high load-bearing capacity. In this study, improved joinability is demonstrated by influencing the
microstructure through tailored solidification rates and a developed heat-treatment chain strategy adapted for
hypoeutectic AlSi systems. Data on microstructure, mechanical, and joining properties are used to develop a
solidification-joining correlation for the SPR process across a range of Si contents and solidification rates. The
purpose is to develop the ability to produce suitable aluminium castings with sufficient joinability, thereby
improving versatility.}},
author = {{Neuser, Moritz and Kaimann, Pia Katharina and Stratmann, Ina and Bobbert, Mathias and Klöckner, Johann Moritz Benedikt and Mann, Moritz and Hoyer, Kay-Peter and Meschut, Gerson and Schaper, Mirko}},
journal = {{Journal of Manufacturing Processes}},
keywords = {{Mechanical joining, Aluminium, Self-piercing riveting, Casting, Microstructure, Joinability AlSi-alloys}},
publisher = {{Elsevier}},
title = {{{Solidification-joinability correlation of hypoeutectic aluminium casting alloys for self-piercing riveting (SPR)}}},
doi = {{https://doi.org/10.1016/j.jmapro.2026.02.040}},
volume = {{164}},
year = {{2026}},
}
@article{64985,
abstract = {{Modern industrial development has necessitated a wide range of joining technologies. Self-pierce riveting has become a prevalent technique for sheet metal assembly, especially in automotive applications. Achieving proper joint geometry and adequate load-bearing capacity depends on appropriate tool selection and precise process control. Material properties and condition also play a significant role in process performance. To accommodate the inevitable variations in component characteristics during production, a robust and stable joining process is essential. The study focuses on investigating the influence of preformed joining partners on the joining process and the joint's load capacity. An EN AW-6014 in T4 condition, as well as an HCT590X, are used as materials for this study. For this purpose, an exemplary process chain consisting of the steps of performing, joining, and shear load testing is studied. Each process step is implemented using an FE model to predict the outcome of subsequent steps. For analysis of the influence of pre-strain, an optimisation software is used to plan and execute variations of the process. These variations are used to create a meta-model that can describe the relationships between pre-forming and characteristic parameters of subsequent process steps. The resulting model is validated by comparing simulation and experimental data. Finally, in a novel approach, the robustness of the presented process chain is analyzed in terms of a tolerable performance level for the joining partners.}},
author = {{Ludwig, Jean-Patrick and Tolke, Emil and Schlichter, Malte Christian and Bobbert, Mathias and Meschut, Gerson}},
issn = {{2666-3309}},
journal = {{Journal of Advanced Joining Processes}},
keywords = {{Self-pierce riveting, FE modelling, Plastic pre-deformation, Meta modelling}},
publisher = {{Elsevier BV}},
title = {{{Numerical analysis of the robustness of self-pierce riveting with pre-formed joining partners}}},
doi = {{10.1016/j.jajp.2026.100391}},
volume = {{13}},
year = {{2026}},
}
@article{58495,
abstract = {{ To reduce CO2 emissions, the industry, particularly in the mobility sector, focuses on lightweight vehicles with multi-material structures. As thermal joining processes are reaching their limits, mechanical techniques such as self-piercing riveting are being used. One innovative solution is the versatile self-piercing riveting process (V-SPR), which combines different material combinations with a multi-range rivet. 1 The joining process is divided into the piercing process and the forming process of the rivet head to the respective sheet thickness. The rivet shaft requires sufficient strength to punch through the punch-sided sheet, and sufficient ductility of the rivet head is required to form onto the punch-sided sheet. To achieve a combination of these requirements, local inductive heat treatment strategies are used for the rivet. To ensure reproducible rivet hardening, a specialised device has been developed for precise rivet positioning in the induction coil and the subsequent quenching process. The heat treatment differs in terms of hardening times and temperatures. In addition, the heat treatment is combined with a subsequent tempering process. The study aims to determine the resulting hardness distributions and microstructures of the rivet and to investigate the influence of different heat treatment strategies on joint formation and load-bearing capacities. The results show that a graded hardening profile has a positive effect on the spreading behaviour of the rivet foot and the forming behaviour of the rivet head. Furthermore, the load-bearing behaviour of the joints is increased. }},
author = {{Holtkamp, Pia Katharina and Kappe, Fabian and Probst, Paula and Bobbert, Mathias and Meschut, Gerson}},
issn = {{1464-4207}},
journal = {{Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications}},
publisher = {{SAGE Publications}},
title = {{{Investigation of local heat treatment strategies for a multi-range capable rivet and the influence on joint formation and load-bearing capacity}}},
doi = {{10.1177/14644207241307508}},
year = {{2025}},
}
@article{58492,
abstract = {{A coupled finite plasticity ductile damage and failure model is proposed for the finite element simulation of clinch joining, which incorporates stress-state dependency and regularisation by gradient-enhancement of the damage variable. Ductile damage is determined based on a failure indicator governed by a failure surface in stress space. The latter is exemplary chosen as a combination of the Hosford–Coulomb and Cockcroft–Latham–Oh failure criteria for the high and low stress triaxiality range, respectively, to cover the wide stress range encountered in forming. Damage is coupled to elasto-plasticity to capture the damage-induced degradation of the stiffness and flow stress. This affects the material behaviour up to failure, thereby realistically altering the stress state. Consequently, especially for highly ductile materials, where substantial necking and localisation precede material fracture, the failure prediction is enhanced. The resulting stress softening is regularised by gradient-enhancement to obtain mesh-objective results. The analysis of a modified punch test experiment emphasises how the damage-induced softening effect can strongly alter the actual stress state towards failure. Moreover, the impact of successful regularisation is shown, and the applicability of the damage and failure model to clinch joining is proven.}},
author = {{Friedlein, Johannes and Mergheim, Julia and Steinmann, Paul}},
issn = {{0022-5096}},
journal = {{Journal of the Mechanics and Physics of Solids}},
keywords = {{Finite plasticity, Ductile damage, Gradient-enhancement, Stress-state dependency, Failure}},
publisher = {{Elsevier BV}},
title = {{{Modelling of stress-state-dependent ductile damage with gradient-enhancement exemplified for clinch joining}}},
doi = {{10.1016/j.jmps.2025.106026}},
volume = {{196}},
year = {{2025}},
}
@inproceedings{59483,
abstract = {{Abstract. The assessment of mechanically joined connections, such as clinched connections, is usually conducted destructively. Applicable non-destructive testing methods like computed tomography are time-consuming and costly, or, like electrical resistance measurement, provide only a limited amount of information. A fast, non-destructive evaluation of the joints condition shall be made possible by using transient dynamic analysis (TDA). It is based on the introduction of sound waves and the evaluation of the response behavior after passing through the structure. This study focuses the application of TDA to clinched shear connections to evaluate the performance of the tactile measuring setup. Twenty-one series were investigated, covering variations in joining task, manufacturing and defect. The evaluation was carried out using machine learning to determine for which series characteristic signals may be detected. It was shown that a classification of the investigated specimens is possible, whereby the classification accuracy depends on the examined variation. Furthermore, the accuracy was evaluated as a function of frequency and results were concluded to identify the limits of the used measuring setup.}},
author = {{Reschke, Gregor and Brosius, Alexander}},
booktitle = {{Materials Research Proceedings}},
issn = {{2474-395X}},
keywords = {{Joining, Machine Learning, Transient Dynamic Analysis}},
location = {{Paderborn}},
pages = {{293--300}},
publisher = {{Materials Research Forum LLC}},
title = {{{Transient dynamic analysis: Performance evaluation of tactile measurement}}},
doi = {{10.21741/9781644903551-36}},
volume = {{52}},
year = {{2025}},
}
@inproceedings{60108,
abstract = {{Abstract. In the field of mechanical engineering, destructive tests such as shear tests of mechanical joints are usually followed by imaging methods such as microsectioning or computed tomography (CT). They can help to interpret the measured load-displacement curves, analyze the failure behavior and validate numerical models. However, due to unloading, springback effects and crack closures can occur, which influence the state of the investigated specimen. In this context, in situ CT is able to explore the testing process with a specimen under load avoiding these influences. For in situ CT investigations, the displacement increase is interrupted at certain stop points. While the displacement is kept constant, the CT scan is performed. However, it was observed that the reaction force reduces during CT scanning, e. g. due to settling effects in the test setup. Although in situ CT is established now in research, little attention is paid to the uncertainties which arise from the discontinuous testing procedure. This study systematically explores the impact of these interruptions on the load-displacement behavior and the geometry of clinch points during tensile shear testing. To quantify the influence of the interruptions, loads at defined displacement levels and the final geometry are evaluated statistically. We found, that the load-displacement behavior of both test groups is similar. Despite some small but significant statistical deviations of the loads and the final geometry, our results show that, discontinuous testing has a high level of significance for the phenomena overserved in shear tests with clinch points.}},
author = {{Köhler, D. and Troschitz, J and Kupfer, R. and Gude, M.}},
booktitle = {{Materials Research Proceedings}},
issn = {{2474-395X}},
publisher = {{Materials Research Forum LLC}},
title = {{{In situ computed tomography – Analysis of settling effects during single-lap shear tests with clinch points}}},
doi = {{10.21741/9781644903551-15}},
volume = {{52}},
year = {{2025}},
}
@article{61825,
abstract = {{Abstract
Industrial x-ray computed tomography (CT) systems with high geometric flexibility are increasingly utilized for large-scale measurement objects or challenging measurement tasks. To maintain high accuracy when deviating from the established circular scan trajectory, trajectory calibration methods using multi-sphere reference objects with known marker positions are commonly employed. These multi-sphere objects can either be scanned together with the measurement object (online trajectory calibration) or in a separate scan (offline trajectory calibration). While offline calibration increases machine time, it generally results in higher scan quality. However, a sufficient pose repeatability is necessary to ensure comparable or even superior accuracy to online calibration. In this contribution, we present a straightforward procedure to compare both types of trajectory calibration in a way that the differences of the results can directly be traced back to the influence of the pose repeatability. The multi-sphere reference object is not only used for trajectory calibration, but simultaneously as a measurement object for repeated measurements. The methodology is tested on both a twin robotic CT system and a conventional CT system that is additionally equipped with a hexapod manipulator for adaptive object tilting. Results showed, independent from the type of trajectory calibration, systematic measurement errors in the order of 10−5–10−4 of measured sphere distances and sphericity values below 50
μ
m
. For sphere distances, random errors were increased by a factor of 5 due to the offline trajectory calibration, but were still low (
<
1
μ
m
) in comparison to systematic errors and the spread of different measurement features. Overall, both investigated systems demonstrated sufficient positioning repeatability for offline trajectory calibration. The method is in general also applicable to any other types of manipulator systems used for CT devices. It provides a workflow for the decision which type of trajectory calibration is preferable for a given CT system.}},
author = {{Butzhammer, Lorenz and Handke, Niklas and Wittl, Simon and Herl, Gabriel and Hausotte, Tino}},
issn = {{0957-0233}},
journal = {{Measurement Science and Technology}},
number = {{2}},
publisher = {{IOP Publishing}},
title = {{{Direct assessment of the influence of pose repeatability on the accuracy of dimensional measurements for computed tomography systems with high degrees of freedom}}},
doi = {{10.1088/1361-6501/ada05a}},
volume = {{36}},
year = {{2025}},
}
@article{64157,
author = {{Friedlein, Johannes and Steinmann, Paul and Mergheim, Julia}},
issn = {{0168-874X}},
journal = {{Finite Elements in Analysis and Design}},
publisher = {{Elsevier BV}},
title = {{{One-way coupled staggered implementation of gradient-enhanced damage models coupled to thermoplasticity}}},
doi = {{10.1016/j.finel.2025.104471}},
volume = {{253}},
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{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}},
}