@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{65373,
abstract = {{To reduce CO₂ emissions, the automotive industry is adopting multi-material structures. Fusion-based joining reaches its limits for aluminium–steel due to brittle intermetallic phases and mismatched thermophysical properties; therefore, mechanical joining (e.g., SPR) is used. Though conventional SPR requires tool changes for different stack-ups. Versatile self-piercing riveting (V-SPR) addresses this with an extended punch actuator and a multi-range-capable rivet (Kappe in PERD16:363–378, 2022), enabling joints up to 600 MPa across varying thicknesses without retooling. With the use of ultra-high-strength steels up to 1000 MPa, optimisation is required. This study quantifies how rivet shank geometry affects joint formation using a design of experiments and validated 2D axisymmetric FE simulations. The optimum depends strongly on the material system. For CP1000–EN AW-6014, maximum interlock f is predicted for a medium shank thickness of about 0.73 mm, a small internal foot radius of 0.620 mm, and a deeper drill depth of 3.136 mm, yielding f fc =0.4503 mm with a desirability of 0.954. For EN AW-6014–EN AW-6014, the optimum shifts to a thinner shank of 0.670 mm, a larger internal foot radius of 0.820 mm and a shallow drill depth of 2.30 mm, giving ffc = 0.3023 mm with a desirability of 1.0. A compromise geometry of 0.713 mm shank thickness, 0.776 mm internal foot radius and 2.755 mm drill depth achieves ffc = 0.3641 mm for CP1000–aluminium and ffc = 0.1851 mm for aluminium–aluminium with an overall desirability D = 0.6378, expanding V-SPR to ultra-high-strength steel–aluminium joints while maintaining aluminium joinability.}},
author = {{Kaimann, Pia Katharina and Ritter, Nico and Bobbert, Mathias and Meschut, Gerson}},
issn = {{2731-6564}},
journal = {{Discover Mechanical Engineering}},
number = {{1}},
publisher = {{Springer Science and Business Media LLC}},
title = {{{Influence of the shank geometry on the joint formation of the versatile self-piercing riveting of ultra-high-strength steel-aluminium and aluminium-aluminium assemblies}}},
doi = {{10.1007/s44245-026-00221-y}},
volume = {{5}},
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{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}},
}
@article{58807,
abstract = {{One of the most important strategies for reducing CO2 emissions in the mobility sector is lightweight construction. In particular, the car body offers several opportunities for weight reduction. Multi-material designs are increasingly being applied to select the most suitable material for the respective load and ultimately achieve synergy effects. For example, aluminium castings are used at the nodes of a spaceframe body. Subsequently, these are joined with profiles to form the bodyshell. To join different materials mechanical joining techniques, such as semi-tubular self-piercing riveting, are deployed. According to the current state of the art, cracks occur in the aluminium castings during the mechanical joining process as a result of the high degree of deformation. Although the aluminium casting alloys of the AlSi-system exhibit low ductility, these alloys reveal excellent castability. In particular, the ability to cast thin structural parts is enabled by the low liquidus point of the near eutectic aluminium casting alloys.
This study addresses the mechanical joining properties of the near eutectic aluminium casting alloy AlSi12, depending on different microstructures. These are achieved by annealing processes and modifying agents. Through an adapted heat treatment, the previously lamellar morphology can be transformed into a globular morphology, which leads to increased ductility and prevents the formation of cracks during the self-piercing riveting (SPR). The joinability is investigated using different die geometries, whereas the joint formation is analysed regarding crack initiation. To evaluate the increased ductility, microstructural and mechanical tests are performed and finally, a microstructure-joinability correlation is established.}},
author = {{Neuser, Moritz and Holtkamp, Pia Katharina and Hoyer, Kay-Peter and Kappe, Fabian and Yildiz, Safak and Bobbert, Mathias and Meschut, Gerson and Schaper, Mirko}},
journal = {{The Journal of Materials: Design and Applications, Part L}},
keywords = {{aluminium, casting, microstructure, joinability, self-piercing riveting}},
location = {{Porto, Portugal}},
publisher = {{Sage Publications}},
title = {{{Mechanical properties and joinability of the near-eutectic aluminium casting alloy AlSi12}}},
doi = {{10.1177/14644207251319922}},
year = {{2025}},
}
@inproceedings{60290,
abstract = {{The constantly increasing demand for climate protection and resource conservation requires innovative and versatile joining processes that improve adaptability to the joining task and robustness to enable flexible manufacturing on a production line. Therefore, the versatile SPR (V-SPR) and tumbling SPR (T-SPR) were developed. Using the example of a mixed material combination HCT590X+Z (t0 = 1.0 mm) / EN AW-6014 T4 (t0 = 2.0 mm), these processes were examined and compared with regard to the binding mechanisms form closure and force closure using micrographs, non-destructive resistance measurements and destructive torsion tests. For this purpose, a new sample geometry was defined, and the methods were adapted to the SPR process variants.}},
author = {{Lüder, Stephan and Holtkamp, Pia Katharina and Wituschek, Simon and Bobbert, Mathias and Meschut, Gerson and Lechner, Michael and Schmale, Hans Christian}},
booktitle = {{Materials Research Proceedings}},
editor = {{Meschut, Gerson and Bobbert, Mathias and Duflou, Joost and Fratini, Livan and Hagenah, Hinnerk and Martins, Paulo A. F. and Merklein, Marion and Micari, Fabrizio}},
issn = {{2474-395X}},
keywords = {{Joining, Self-Piercing Riveting, Sheet Metal}},
location = {{Paderborn}},
pages = {{101 -- 108}},
publisher = {{Materials Research Forum LLC}},
title = {{{Analysis of the binding mechanisms depending on versatile process variants of self-piercing riveting}}},
doi = {{10.21741/9781644903551-13}},
volume = {{52}},
year = {{2025}},
}
@article{57742,
author = {{Böhnke, Max and Bielak, Christian Roman and Beck, Robert and Bobbert, Mathias and Meschut, Gerson}},
issn = {{2223-7690}},
journal = {{Friction}},
publisher = {{Tsinghua University Press}},
title = {{{Development of a friction model for the numerical simulation of clinching processes}}},
doi = {{10.26599/frict.2025.9441052}},
year = {{2024}},
}
@article{59585,
abstract = {{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.}},
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}},
}
@article{61413,
abstract = {{Climate change has led to a large number of countries deciding to reduce carbon dioxide (CO2) emissions significantly. As the mobility sector is a major contributor to CO2, various strategies are being pursued to achieve the climate targets set. An increasingly applied lightweight design method is the use of multi-material constructions. To join these structures, mechanical joining technologies such as self-pierce riveting are being used. As a result of the currently rigid tool systems, which cannot react to changing boundary conditions, a large number of rivet–die combinations is required to join the rising number of materials as well as material thickness combinations. Thus, new, versatile joining technologies are needed that can react to the described changes. The versatile self-piercing riveting (V-SPR) process is one possible approach. In this process, different material thicknesses can be joined by using a multi-range capable rivet which is set by a joining system with extended actuator technology. In this study, the V-SPR joining process is analysed numerically according to the influence of the geometrical rivet parameters on the joints characteristics as well as the resulting material flow. The investigations showed that the shank geometry has a decisive influence on the expansion of the rivet. Furthermore, the rivet length could be proven to be an influencing factor. By changing the head radii and the protrusion height, the forming behaviour of the rivet head onto the punch-sided joining part could be improved and thus the formation of air pockets was prevented. Based on the numerical investigations, a novel rivet geometry was developed and produced by machining. Subsequently, experimentally produced joints were analysed according to their joint formation and load-bearing capacity.}},
author = {{Kappe, Fabian and Bobbert, Mathias and Meschut, Gerson}},
issn = {{0954-4089}},
journal = {{Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering}},
publisher = {{SAGE Publications}},
title = {{{Investigation of the influence of the rivet geometry on joint formation for a versatile self-piercing riveting process}}},
doi = {{10.1177/09544089241263141}},
year = {{2024}},
}
@article{61416,
abstract = {{Abstract
An efficient lightweight construction method is the combination of different materials in order to adapt the structure to the applied load. To join these multi-material structures mechanical joining technologies are applied. However, the rigid tooling systems cannot be adjusted to changing boundary conditions which is why new, versatile joining technologies are required. In the versatile self-piercing riveting (V-SPR) process presented in [1] different material combination are joined by using a multi-range capable rivet. The rivet head is formed onto the respective thickness of the joint by an outer punch. In order to punch thru the upper sheet a great rivet hardness is required whereas a lower hardness is required for the subsequent forming of the rivet head. To achieve a combination of these requirements, this study investigates a local heat treatment of the rivet. The aim is to determine the feasibility of such a heat treatment as well as to investigate the influence on the joint formation.}},
author = {{Kappe, Fabian and Bobbert, Mathias and Meschut, Gerson}},
issn = {{1757-8981}},
journal = {{IOP Conference Series: Materials Science and Engineering}},
number = {{1}},
publisher = {{IOP Publishing}},
title = {{{Influence of local heat treatment of rivets on the joint formation of a versatile joining process}}},
doi = {{10.1088/1757-899x/1307/1/012009}},
volume = {{1307}},
year = {{2024}},
}
@inproceedings{43090,
abstract = {{Abstract. The application of the mechanical joining process clinching allows the assembly of different sheet metal materials with a wide range of material thickness configurations, which is of interest for lightweight multi-material structures. In order to be able to predict the clinched joint properties as a function of the individual manufacturing steps, current studies focus on numerical modeling of the entire clinching process chain. It is essential to be able to take into account the influence of the joining process-induced damage on the load-bearing capacity of the joint during the loading phase. This study presents a numerical damage accumulation in the clinching process based on an implemented Hosford-Coulomb failure model using a 3D clinching process model applied on the aluminum alloy EN AW-6014 in temper T4. A correspondence of the experimentally determined failure location with the element of the highest numerically determined damage accumulation is shown. Moreover, the experimentally determined failure behavior is predicted to be in agreement in the numerical loading simulation with transferred pre-damage from the process simulation. }},
author = {{Bielak, Christian Roman and Böhnke, Max and Friedlein, Johannes and Bobbert, Mathias and Mergheim, Julia and Steinmann, Paul and Meschut, Gerson}},
booktitle = {{Materials Research Proceedings}},
issn = {{2474-395X}},
publisher = {{Materials Research Forum LLC}},
title = {{{Numerical analysis of failure modeling in clinching process chain simulation}}},
doi = {{10.21741/9781644902417-33}},
year = {{2023}},
}
@inproceedings{43462,
abstract = {{Abstract. In the numerical simulation of mechanical joining technologies such as clinching, the material modeling of the joining parts is of major importance. This includes modeling the damage and failure behavior of the materials in accordance with varying occurring stress states. This paper presents a calibration method of three different fracture models. The calibration of the models is done by use of experimental data from a modified punch test, tensile test and bulge test in order to map the occurring stress states from clinching processes and to precisely model the resulting failure behavior. Experimental investigations were carried out for an aluminum alloy EN AW-6014 in temper T4 and compared with the simulative results generated in LS-DYNA. The comparison of force-displacement curves and failure initiation shows that the Hosford–Coulomb model predicts the failure behavior for the material used and the tests applied with the best accuracy. }},
author = {{Böhnke, Max and Bielak, Christian Roman and Friedlein, Johannes and Bobbert, Mathias and Mergheim, Julia and Steinmann, Paul and Meschut, Gerson}},
booktitle = {{Materials Research Proceedings}},
issn = {{2474-395X}},
publisher = {{Materials Research Forum LLC}},
title = {{{A calibration method for failure modeling in clinching process simulations}}},
doi = {{10.21741/9781644902417-34}},
year = {{2023}},
}