@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{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     = {{<jats:p>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.</jats:p>}},
  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.</jats:p>}},
  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.</jats:p>}},
  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.</jats:p>}},
  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.</jats:p>}},
  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{61149,
  abstract     = {{The use of continuous fiber-reinforced thermoplastics (FRTP) in automotive industry increases due to their excellent material properties and possibility of rapid processing. The scale spanning heterogeneity of their material structure and its influence on the material behavior, however, presents significant challenges for most joining technologies, such as self-piercing riveting (SPR). During mechanical joining, the material structure is significantly altered within and around the joining zone, heavily influencing the material behavior. A comprehensive understanding of the underlying phenomena of material alteration during the SPR process is essential as basis for validating numerical simulations. This study examines the material structure at ten stages of a step-setting test of SPR with two FRTP sheets with glass-fiber reinforcement. Utilizing X-ray computed tomography (CT), the damage phenomena within different areas of the setting test are analyzed three-dimensionally and key parameters are quantified. Dominating phenomena during the penetration of the rivet into the laminate are fiber failure (FF), interfiber failure (IFF) and fiber bending, while delamination, fiber kinking and roving splitting are also observed. At the final stages, the bottom layers of the second sheet collapse and form a bulge into the cavity of the die.}},
  author       = {{Dargel, Alrik and Gröger, Benjamin and Schlichter, Malte Christian and Gerritzen, Johannes and Köhler, Daniel and Meschut, Gerson and Gude, Maik and Kupfer, Robert}},
  booktitle    = {{Proceedings of the 8th International Conference on Integrity-Reliability-Failure (IRF2025)}},
  editor       = {{Gomes, J.F. Silva and Meguid, Shaker A.}},
  isbn         = {{9789727523238}},
  keywords     = {{self-piercing riveting, computed tomography, thermoplastic composites, process-structure-interaction}},
  location     = {{Porto}},
  publisher    = {{FEUP}},
  title        = {{{LOCAL DEFORMATION AND FAILURE OF COMPOSITES DURING SELF-PIERCING RIVETING: A CT BASED MICROSTRUCTURE INVESTIGATION}}},
  doi          = {{10.24840/978-972-752-323-8}},
  year         = {{2025}},
}

@article{59585,
  abstract     = {{<jats:p>Similar to bulk metal forming, clinch joining is characterised by large plastic deformations and a variety of different 3D stress states, including severe compression. However, inherent to plastic forming is the nucleation and growth of defects, whose detrimental effects on the material behaviour can be described by continuum damage models and eventually lead to material failure. As the damage evolution strongly depends on the stress state, a stress-state-dependent model is utilised to correctly track the accumulation. To formulate and parameterise this model, besides classical experiments, so-called modified punch tests are also integrated herein to enhance the calibration of the failure model by capturing a larger range of stress states and metal-forming-specific loading conditions. Moreover, when highly ductile materials are considered, such as the dual-phase steel HCT590X and the aluminium alloy EN AW-6014 T4 investigated here, strong necking and localisation might occur prior to fracture. This can alter the stress state and affect the actual strain at failure. This influence is captured by coupling plasticity and damage to incorporate the damage-induced softening effect. Its relative importance is shown by conducting inverse parameter identifications to determine damage and failure parameters for both mentioned ductile metals based on up to 12 different experiments.</jats:p>}},
  author       = {{Friedlein, Johannes and Böhnke, Max and Schlichter, Malte Christian and Bobbert, Mathias and Meschut, Gerson and Mergheim, Julia and Steinmann, Paul}},
  issn         = {{2504-4494}},
  journal      = {{Journal of Manufacturing and Materials Processing}},
  number       = {{4}},
  publisher    = {{MDPI AG}},
  title        = {{{Material Parameter Identification for a Stress-State-Dependent Ductile Damage and Failure Model Applied to Clinch Joining}}},
  doi          = {{10.3390/jmmp8040157}},
  volume       = {{8}},
  year         = {{2024}},
}