@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{62005,
author = {{Böhm, Yannic and Kappe, Fabian and Han, Daxin and Nordmann, Elmar and Yang, Keke and Jendrny, Jörg and Gorr, Eugen and Meschut, Gerson}},
issn = {{1526-6125}},
journal = {{Journal of Manufacturing Processes}},
pages = {{171--184}},
publisher = {{Elsevier BV}},
title = {{{Single-step self-punching lockbolt process and equipment development for pre-hole-free joining of aluminum sheets using a dual-die system}}},
doi = {{10.1016/j.jmapro.2025.10.027}},
volume = {{155}},
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{60439,
abstract = {{Abstract. Mechanical joints are traditionally analyzed through destructive micrograph analysis, which may compromise internal geometry and morphology, as evidenced by radial cracks in semi-tubular self-pierce riveting. In contrast, industrial X-ray computed tomography (XCT) offers a non-destructive method for component diagnosis, providing volumetric insights without damaging the sample and enabling dimensional measurement. The DFG-funded Collaborative Research Center TRR 285 is exploring XCT's application in assessing mechanical joinability across various joining processes and materials, particularly in multi-material systems like steel-aluminum joints. XCT faces challenges in accurately capturing multi-material compositions, leading to artifacts that complicate interface detection. This research aims to validate XCT for joint investigations, yielding quantitative characteristics that surpass those from traditional micrograph analysis.}},
author = {{Lechner, M. and Borgert, Thomas and Busch, Matthias and Harms, A. and Holtkamp, Pia Katharina and Römisch, D. and Wituschek, Simon and Kappe, Fabian}},
booktitle = {{Materials Research Proceedings}},
issn = {{2474-395X}},
publisher = {{Materials Research Forum LLC}},
title = {{{Non-destructive testing in versatile joining processes}}},
doi = {{10.21741/9781644903551-12}},
volume = {{52}},
year = {{2025}},
}
@article{52201,
author = {{Han, Daxin and Kappe, Fabian and Vorderbrüggen, Julian and Jendrny, Jörg and Gorr, Eugen and Meschut, Gerson}},
issn = {{1526-6125}},
journal = {{Journal of Manufacturing Processes}},
keywords = {{Industrial and Manufacturing Engineering, Management Science and Operations Research, Strategy and Management}},
pages = {{92--108}},
publisher = {{Elsevier BV}},
title = {{{Single-step self-punching lockbolt process for aluminum sheets without pre-hole}}},
doi = {{10.1016/j.jmapro.2024.02.043}},
volume = {{116}},
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{52831,
abstract = {{Monitoring force-displacement or force-time curves is a widely used quality control technique in the field of mechanical joining. For online monitoring of self-piercing riveting, envelope curves are often used to define a tolerance zone for the measured setting force. However, the measurement uncertainty is typically not considered and the force curve of a joint can be wrongly rated as non-conform due to measurement errors and noise. In this article, we present a method for dynamical online filtering and uncertainty determination for noisy force curves using two types of Bayesian filters. The methodology is based on a Bayesian probability framework using a priori information for the process curve and sensor noise. To investigate the general feasibility of the method, force measurements with different noise levels are simulated and processed. The conformity is further assessed taking the uncertainty of the filtered signal into account. The results show that the Bayes filter technique is principally able to reduce noise for well-known characteristics of the process curve and sensor noise. Advantages over common filtering techniques, especially for experimental conditions with less known characteristics, are still to be verified. The methodology could be used in future for closed-loop controls to adapt process parameters dynamically. }},
author = {{Butzhammer, Lorenz and Kappe, Fabian and Meschut, Gerson and Hausotte, Tino }},
booktitle = {{Materials Research Proceedings}},
issn = {{2474-395X}},
publisher = {{Materials Research Forum LLC}},
title = {{{Dynamic conformity assessment for joining force monitoring using Bayes filters}}},
doi = {{10.21741/9781644902417-48}},
year = {{2023}},
}
@inproceedings{52821,
abstract = {{Due to economic and ecological framework conditions, a resource-saving utilization of raw materials and energy is becoming increasingly important in particular in the mobility sector. For the reduction of moving masses and the resources consumed, lightweight construction technologies are part of modern production processes in vehicle manufacturing, for example in the form of multi-material systems. Challenging in the manufacture of multi-material systems especially in view of changing supply chains is the variety of materials and geometries that bring conventional joining processes to their limits. Therefore, new processes are required, which can react versatile to process and disturbance variables. A widely used industrial joining process is semi-tubular self-piercing riveting, which is however a rigid process. To increase the versatility, the two newly established processes multi-range self-piercing riveting and tumbling self-piercing riveting are combined and the capabilities for targeted material flow control are united. Therefore, an innovative two-stage process based on the combination is introduced in this paper. The rivet is set with the multi-range self-piercing riveting process with an overlap of the rivet head and then formed by a tumbling process. Further, a specific adaptation of the tumbling strategy is used to investigate the possibility of reducing cracks in the rivet head. Thereby, different tumbling strategies are used and similar geometric joint formations are achieved to compare the results. }},
author = {{Wituschek, Simon and Kappe, Fabian and Meschut, Gerson and Lechner, Michael}},
booktitle = {{Materials Research Proceedings}},
issn = {{2474-395X}},
publisher = {{Materials Research Forum LLC}},
title = {{{Combination of versatile self-piercing riveting processes}}},
doi = {{10.21741/9781644902417-16}},
year = {{2023}},
}
@article{36332,
abstract = {{AlSi casting alloys combine excellent castability with high strength. Hence, this group of alloys is often used in the automotive sector. The challenge for this application is the brittle character of these alloys which leads to cracks during joint formation when mechanical joining technologies are used. A rise in ductility can be achieved by a considerable increase in the solidification rate which results in grain refinement. High solidification rates can be realized in twin–roll casting (TRC) by water-cooled rolls. Therefore, a hypoeutectic EN AC–AlSi9 (for European Norm - aluminum cast product) is manufactured by the TRC process and analyzed. Subsequently, joining investigations are performed on castings in as-cast and heat-treated condition using the self-piercing riveting process considering the joint formation and the load-bearing capacity. Due to the fine microstructure, the crack initiation can be avoided during joining, while maintaining the joining parameters, especially by specimens in heat treatment conditions. Furthermore, due to the extremely fine microstructure, the load-bearing capacity of the joint can be significantly increased in terms of the maximum load-bearing force and the energy absorbed.}},
author = {{Neuser, Moritz and Kappe, Fabian and Ostermeier, Jakob and Krüger, Jan Tobias and Bobbert, Mathias and Meschut, Gerson and Schaper, Mirko and Grydin, Olexandr}},
issn = {{1438-1656}},
journal = {{Advanced Engineering Materials}},
keywords = {{Condensed Matter Physics, General Materials Science}},
number = {{10}},
publisher = {{Wiley}},
title = {{{Mechanical Properties and Joinability of AlSi9 Alloy Manufactured by Twin‐Roll Casting}}},
doi = {{10.1002/adem.202200874}},
volume = {{24}},
year = {{2022}},
}
@article{34216,
abstract = {{Mechanical joining technologies are increasingly used in multi-material lightweight constructions and offer opportunities to create versatile joining processes due to their low heat input, robustness to metallurgical incompatibilities and various process variants. They can be categorised into technologies which require an auxiliary joining element, or do not require an auxiliary joining element. A typical example for a mechanical joining process with auxiliary joining element is self-piercing riveting. A wide range of processes exist which are not requiring an auxiliary joining element. This allows both point-shaped (e.g., by clinching) and line-shaped (e.g., friction stir welding) joints to be produced. In order to achieve versatile processes, challenges exist in particular in the creation of intervention possibilities in the process and the understanding and handling of materials that are difficult to join, such as fiber reinforced plastics (FRP) or high-strength metals. In addition, predictive capability is required, which in particular requires accurate process simulation. Finally, the processes must be measured non-destructively in order to generate control variables in the process or to investigate the cause-effect relationship. This paper covers the state of the art in scientific research concerning mechanical joining and discusses future challenges on the way to versatile mechanical joining processes.}},
author = {{Meschut, Gerson and Merklein, M. and Brosius, A. and Drummer, D. and Fratini, L. and Füssel, U. and Gude, M. and Homberg, Werner and Martins, P.A.F. and Bobbert, Mathias and Lechner, M. and Kupfer, R. and Gröger, B. and Han, Daxin and Kalich, J. and Kappe, Fabian and Kleffel, T. and Köhler, D. and Kuball, C.-M. and Popp, J. and Römisch, D. and Troschitz, J. and Wischer, Christian and Wituschek, S. and Wolf, M.}},
issn = {{2666-3309}},
journal = {{Journal of Advanced Joining Processes}},
keywords = {{Mechanical Engineering, Mechanics of Materials, Engineering (miscellaneous), Chemical Engineering (miscellaneous)}},
publisher = {{Elsevier BV}},
title = {{{Review on mechanical joining by plastic deformation}}},
doi = {{10.1016/j.jajp.2022.100113}},
volume = {{5}},
year = {{2022}},
}
@article{34241,
abstract = {{Due to the increasing use of multi-material constructions and the resulting material incompatibilities, mechanical joining technologies are gaining in importance. The reasons for this are the variety of joining possibilities as well as high load-bearing capacities. However, the currently rigid tooling systems cannot react to changing boundary conditions, such as changed sheet thicknesses or strength. For this reason, a large number of specialised joining processes have been developed to expand the range of applications. Using a versatile self-piercing riveting process, multi-material structures are joined in this paper. In this process, a modified tool actuator technology is combined with multi-range capable auxiliary joining parts. The multi-range capability of the rivets is achieved by forming the rivet head onto the respective thickness of the joining part combination without creating a tooling set-up effort. The joints are investigated both experimentally on the basis of joint formation and load-bearing capacity tests as well as by means of numerical simulation. It turned out that all the joints examined could be manufactured according to the defined standards. The load-bearing capacities of the joints are comparable to those of conventionally joined joints. In some cases the joint fails prematurely, which is why lower energy absorptions are obtained. However, the maximum forces achieved are higher than those of conventional joints. Especially in the case of high-strength materials arranged on the die side, the interlock formation is low. In addition, the use of die-sided sheets requires a large deformation of the rivet head protrusion, which leads to an increase in stress and, as a result, to damage if the rivet head. However, a negative influence on the joint load-bearing capacity could be excluded.}},
author = {{Kappe, Fabian and Wituschek, Simon and Bobbert, Mathias and Lechner, Michael and Meschut, Gerson}},
issn = {{0944-6524}},
journal = {{Production Engineering}},
keywords = {{Industrial and Manufacturing Engineering, Mechanical Engineering}},
publisher = {{Springer Science and Business Media LLC}},
title = {{{Joining of multi-material structures using a versatile self-piercing riveting process}}},
doi = {{10.1007/s11740-022-01151-w}},
year = {{2022}},
}
@inbook{34275,
abstract = {{Due to economic and ecological requirements and the associated trend towards lightweight construction, mechanical joining technologies like self-piercing riveting are gaining in importance. In addition, the increase in lightweight multi-material joints has led to the development of many different mechanical joining technologies which can only be applied to join a small number of material combinations. This leads to low process efficiency, and in the case of self-piercing riveting, to a large number of required tool changes. Another approach focuses on reacting to changing boundary conditions as well as the creation of customised joints by using adaptive tools, versatile auxiliary joining parts or modified process kinematics. Therefore, this study investigates the influence of increased die-sided kinematics on joint formation in self-piercing riveting process. The aim is to achieve an improvement of the joint properties by superimposing the punch feed. Furthermore, it is intended to reduce required tool changes due to the improved joint design. The investigations were carried out by means of a 2D-axisymmetric numerical simulation model using the LS-Dyna simulation software. After the validation of the process model, the die was extended to include driven die elements. Using the model, different kinematics as well as their effects on the joint formation and the internal stress concentration could be analysed. In principle, the increased actuator technology enabled an increase of the interlock formation for both pure aluminium and multi-material joints consisting of steel and aluminium. However, the resulting process forces were higher during the process phases of punching and spreading.}},
author = {{Kappe, Fabian and Wituschek, Simon and de Pascalis, Vincenzo and Bobbert, Mathias and Lechner, Michael and Meschut, Gerson}},
booktitle = {{Materials Design and Applications IV}},
isbn = {{9783031181290}},
issn = {{1869-8433}},
publisher = {{Springer International Publishing}},
title = {{{Numerical Investigation of the Influence of a Movable Die Base on Joint Formation in Semi-tubular Self-piercing Riveting}}},
doi = {{10.1007/978-3-031-18130-6_10}},
year = {{2022}},
}
@article{29858,
author = {{Kappe, Fabian and Schadow, Luca and Bobbert, Mathias and Meschut, Gerson}},
journal = {{Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications}},
title = {{{Increasing flexibility of self-piercing riveting by reducing tool–geometry combinations using cluster analysis in the application of multi-material design}}},
doi = {{10.1177/14644207211070992}},
year = {{2022}},
}
@article{29857,
author = {{Kappe, Fabian and Wituschek, Simon and Bobbert, Mathias and Meschut, Gerson}},
journal = {{Production Engineering}},
title = {{{Determining the properties of multi‑range semi‑tubular self‑piercing riveted joints}}},
doi = {{https://doi.org/10.1007/s11740-022-01105-2}},
year = {{2022}},
}
@article{24537,
author = {{Neuser, Moritz and Kappe, Fabian and Busch, M and Grydin, Olexandr and Bobbert, Mathias and Schaper, Mirko and Meschut, Gerson and Hausotte, T}},
issn = {{1757-8981}},
journal = {{IOP Conference Series: Materials Science and Engineering}},
title = {{{Joining suitability of cast aluminium for self-piercing riveting}}},
doi = {{10.1088/1757-899x/1157/1/012005}},
year = {{2021}},
}
@inproceedings{34222,
abstract = {{Driven by the CO2-emission law by the European government and the increasing costs for raw materials as well as energy, the automotive industry is increasingly using multi-material constructions. This leads to a continuous increase in the use of mechanical joining techniques and especially the self-piercing riveting is of particular importance. The reason for this is the wide range of joining possibilities as well as the high load-bearing capacities of the joints. To be able to react to changing boundary conditions, like material thickness or strength variation of the sheets, research work is crucial with regard to the increase of versatility. In this paper, a numerical study of the influences on the selfpiercing riveting process is presented. For this purpose, the influence of different process parameters such as rivet length and die depth on various quality-relevant characteristics were investigated. With the help of the design of experiment, significant influences were determined and interactions between the individual parameters are shown.}},
author = {{Kappe, Fabian and Bielak, Christian Roman and Sartisson, Vadim and Bobbert, Mathias and Meschut, Gerson}},
booktitle = {{ESAFORM 2021}},
publisher = {{University of Liege}},
title = {{{Influence of rivet length on joint formation on self-piercing riveting process considering further process parameters}}},
doi = {{10.25518/esaform21.4277}},
year = {{2021}},
}
@article{22798,
abstract = {{The predictive quality of numerical simulations for mechanical joining processes depends on the implemented material model, especially regarding the plasticity of the joining parts. Therefore, experimental material characterization processes are conducted to determine the material properties of sheet metal and generate flow curves. In this regard, there are a number of procedures which are accompanied by varying experimental efforts. This paper presents various methods of determining flow curves for HCT590X as well as EN AW-6014, including varying specimen geometries and diverse hardening laws for extrapolation procedures. The flow curves thus generated are compared considering the variety of plastic strains occurring in mechanical joining processes. The material data generated are implemented in simulation models for the joining technologies, clinching and self-piercing riveting. The influence of the varied methods on the predictive accuracy of the simulation model is analysed. The evaluation of the differing flow curves is achieved by comparing the geometric formation of the joints and the required joining forces of the processes with experimentally investigated joints.}},
author = {{Böhnke, Max and Kappe, Fabian and Bobbert, Mathias and Meschut, Gerson}},
issn = {{2195-8572}},
journal = {{Materials Testing}},
number = {{6}},
pages = {{493--500}},
publisher = {{De Gruyter}},
title = {{{Influence of various procedures for the determination of flow curves on the predictive accuracy of numerical simulations for mechanical joining processes}}},
doi = {{10.1515/mt-2020-0082}},
volume = {{63}},
year = {{2021}},
}
@article{34226,
abstract = {{The increasing use of multi-material constructions lead to a continuous increase in the use of mechanical joining techniques due to the wide range of joining possibilities as well as the high load-bearing capacities of the joints. Nevertheless, the currently rigid tool systems are not able to react to changing boundary conditions, like changing the material-geometry-combination. Therefore research work is crucial with regard to versatile joining systems. In this paper, a new approach for a versatile self-piercing riveting process considering the joining system as well as the auxiliary joining part is presented.}},
author = {{Kappe, Fabian and Bobbert, Mathias and Meschut, Gerson}},
issn = {{1662-9795}},
journal = {{Key Engineering Materials}},
keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}},
pages = {{3--10}},
publisher = {{Trans Tech Publications, Ltd.}},
title = {{{New Approach for Versatile Self Piercing Riveting: Joining System and Auxiliary Part}}},
doi = {{10.4028/www.scientific.net/kem.883.3}},
volume = {{883}},
year = {{2021}},
}
@article{30200,
author = {{Wituschek, Simon and Kappe, Fabian and Lechner, Michael}},
journal = {{Production Engineering}},
title = {{{Investigation of the influence of varying tumbling strategies on a tumbling self-piercing riveting process}}},
doi = {{10.1007/s11740-021-01099-3}},
year = {{2021}},
}