@article{34243, abstract = {{ In view of economic and ecological trends, the concepts for lightweight construction in transport systems are becoming increasingly important. These are frequently applied in the form of multi-material systems, which are characterized by the selective use of materials and geometries. One major challenge in the manufacturing of multi-material systems is the joining of the individual components to form a complete system. Mechanical joining processes such as semi-tubular self-piercing riveting are frequently used for this application but reach their limits concerning the number of combinations of geometry and material. In order to react to the requirements and to increase the versatility of semi-tubular self-pierce riveting, a process combination consisting of a tumbling process and a self-pierce riveting process has been presented previously. This process combination is used in this work to investigate the versatility and to identify the influencing parameters on it. For this purpose, experiments are conducted to identify process-side influence possibilities. The tests are performed with a dual-phase steel aluminum alloy to represent the varying mechanical characteristics of multi-material systems. Furthermore, the initial sheet thicknesses of the joining partners are varied in several steps. In addition to the geometric joint formation used to describe the undercut, the rivet head end position and the residual sheet thickness, the joining process, is also analyzed during the investigations. Further, the innovative joining process is evaluated by comparing it with a conventional self-piercing riveting process. The knowledge obtained represents a basis for the identification and evaluation of the versatility of the process combination. }}, author = {{Wituschek, Simon and Kappe, Fabian and Meschut, Gerson and Lechner, Michael}}, issn = {{1464-4207}}, journal = {{Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications}}, keywords = {{Mechanical Engineering, General Materials Science}}, publisher = {{SAGE Publications}}, title = {{{Geometric and mechanical joint characterization of conventionally and tumbled self-piercing riveting joints}}}, doi = {{10.1177/14644207221135400}}, year = {{2022}}, } @article{34242, 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{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{34244, author = {{Kappe, Fabian and Zirngibl, Christoph and Schleich, Benjamin and Bobbert, Mathias and Wartzack, Sandro 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 = {{1438--1448}}, publisher = {{Elsevier BV}}, title = {{{Determining the influence of different process parameters on the versatile self-piercing riveting process using numerical methods}}}, doi = {{10.1016/j.jmapro.2022.11.019}}, volume = {{84}}, 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{30647, abstract = {{The increasing economic and ecological demands on the mobility sector require efforts to reduce resource consumption in both the production and utilization phases. The use of lightweight construction technologies can save material and increase energy efficiency during operation. Multi-material systems consisting of different materials and geometries are used to achieve weight reduction. Since conventional joining processes reach their limits in the connection of these components, new methods and technologies are necessary in order to be able to react versatilely to varying process and disturbance variables. For fundamental investigations of new possibilities in joining technology, numerical investigations are helpful to identify process parameters. To generate valid results, robust and efficient material models are developed which are adapted to the requirements of versatile joining technologies, for instance to the high plastic strains associated with self-piercing riveting. To describe the inherent strain-induced plastic orthotropy of sheet metal an anisotropic Hill-plasticity model is formulated. Tensile tests for different sheet orientations are conducted both experimentally and numerically to adjust the anisotropic material parameters by inverse parameter identification for aluminium EN AW-6014 and steel HCT590X. Then, the layer compression test is used to validate the model and the previously identified parameters.}}, author = {{Friedlein, J. and Wituschek, S. and Lechner, M. and Mergheim, J. and Steinmann, P.}}, journal = {{IOP Conference Series: Materials Science and Engineering}}, pages = {{012004}}, title = {{{Inverse parameter identification of an anisotropic plasticity model for sheet metal}}}, doi = {{10.1088/1757-899X/1157/1/012004}}, volume = {{1157}}, year = {{2021}}, } @article{30719, abstract = {{Due to increasing demands regarding ecological and economic specifications in vehicle design, the effort required for production is continuously increasing. One trend is the increased use of multi-material systems, which are characterised by the use of different materials such as high-strength steels or aluminium alloys. In addition to the varying mechanical properties of the components, an increased number of variants accompanied by different geometries is leading to increasing challenges on body construction. For the assembly and connection of the individual components, conventional joining methods reach their limitations. Therefore, new joining methods are necessary, which feature properties of versatility and can adapt to process and disturbance variables. One way of achieving tailored joints is to use a tumbling self-piercing riveting process. For the design of the process route, numerical investigations are necessary for which a characterisation of the friction properties is necessary. This paper therefore investigates the contact and friction conditions that occur in a tumbling self-piercing riveting process. The individual contacts between the process components are identified and based on this, suitable processes for the characterisation of the friction factors - and coefficients are selected and performed.}}, author = {{Wituschek, S. and Lechner, M.}}, journal = {{Key Engineering Materials}}, pages = {{27--34}}, title = {{{Friction Characterisation for a Tumbling Self-Piercing Riveting Process}}}, doi = {{10.4028/www.scientific.net/kem.883.27}}, volume = {{883}}, year = {{2021}}, } @article{30718, abstract = {{The growing demands of resource-saving processes and products are leading to increasing importance of lightweight construction for the automotive industry. One approach is multi-material design, which uses high-strength steels and aluminium alloys in the production of vehicle bodies. Therefore, reliable processes for joining components with different mechanical properties and geometries are necessary. As conventional joining processes reach their limits, new versatile processes and methods are required which can adapt to different process conditions and disturbance variables. A widely used joining process to join different materials is self-piercing riveting as a joining by forming method, however it is characterised as inflexible to changing process conditions due to a linear process kinematic and rigid dies. An approach to extend the process limits is the application of a tumbling kinematic for the punch. Thus, an adapted tumbling strategy can be used to influence the joining process and to achieve a controlled material flow in order to manufacture tailored joints. For the fundamental investigation of the process, numerical investigations are necessary. In order to achieve high model quality a precise material modelling is crucial. Therefore, a characterisation of the materials HCT590X+Z and EN AW-6014 as typical materials of multi-material mixes and the rivet material 38B2 is performed. Due to the different stress conditions during tumbling self-piercing riveting suitable characterisation methods are selected and carried out.}}, author = {{Wituschek, S. and Lechner, M.}}, journal = {{ESAFORM 2021}}, title = {{{Material characterisation methods for a tumbling self-piercing riveting process}}}, doi = {{10.25518/esaform21.398}}, year = {{2021}}, } @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}}, } @article{30721, author = {{Wituschek, S. and Kuball, C. M. and Merklein, M. and Lechner, M.}}, journal = {{Defect and Diffusion Forum}}, pages = {{132--137}}, title = {{{Test Method for Friction Characterization of Rivets}}}, doi = {{10.4028/www.scientific.net/ddf.404.132}}, volume = {{404}}, year = {{2020}}, } @inproceedings{20680, author = {{Kappe, Fabian and Wituschek, Simon and Lechner, Michael and Bobbert, Mathias and Meschut, Gerson and Merklein, Marion}}, location = {{Darmstadt }}, title = {{{Investigation of influencing parameters on the joint formation of the self-piercing riveting process}}}, year = {{2020}}, }