@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}}, } @inbook{52454, author = {{Böhnke, Max and Bielak, Christian Roman and Bobbert, Mathias and Meschut, Gerson}}, booktitle = {{Lecture Notes in Mechanical Engineering}}, isbn = {{9783031413407}}, issn = {{2195-4356}}, publisher = {{Springer Nature Switzerland}}, title = {{{Experimental and Numerical Investigation of Clinched Joints Under Shear Tensile Loading at High Strain Rates}}}, doi = {{10.1007/978-3-031-41341-4_12}}, year = {{2023}}, } @inproceedings{43463, author = {{Friedlein, Johannes and Bielak, Christian Roman and Böhnke, Max and Bobbert, Mathias and Mergheim, Julia and Steinmann, Paul and Meschut, Gerson}}, booktitle = {{Materials Research Proceedings}}, publisher = {{Materials Research Forum LLC}}, title = {{{Influence of plastic orthotropy on clinching of sheet metal}}}, doi = {{10.21741/9781644902417-17 }}, year = {{2023}}, } @inbook{52614, author = {{Bielak, Christian Roman and Böhnke, Max and Bobbert, Mathias and Meschut, Gerson}}, booktitle = {{Lecture Notes in Mechanical Engineering}}, isbn = {{9783031413407}}, issn = {{2195-4356}}, publisher = {{Springer Nature Switzerland}}, title = {{{Numerical Investigation of the Coupled Friction Behavior in the Clinching Process Chain}}}, doi = {{10.1007/978-3-031-41341-4_15}}, year = {{2023}}, } @article{34213, abstract = {{In this paper, a study based on experimental and numerical simulations is performed to analyze fatigue cracks in clinched joints. An experimental investigation is conducted to determine the failure modes of clinched joints under cyclic loading at different load amplitudes with single-lap shear tests. In addition, numerical FEM simulations of clinching process and subsequent shear loading are performed to support the experimental investigations by analyzing the state of stresses at the location of failure. An attempt is made to explain the location of crack initiation in the experiments using evaluation variables such as contact shear stress and maximum principal stress.}}, author = {{Ewenz, L. and Bielak, Christian Roman and Otroshi, Mortaza and Bobbert, Mathias and Meschut, Gerson and Zimmermann, M.}}, issn = {{0944-6524}}, journal = {{Production Engineering}}, keywords = {{Industrial and Manufacturing Engineering, Mechanical Engineering}}, number = {{2-3}}, pages = {{305--313}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Numerical and experimental identification of fatigue crack initiation sites in clinched joints}}}, doi = {{10.1007/s11740-022-01124-z}}, volume = {{16}}, year = {{2022}}, } @article{32413, abstract = {{Background. Clinching is a conventional cold forming process in which two or more sheets can be joined without auxiliary parts. A pre-forming of the parts to be joined, which is introduced by previous manufacturing steps, has an influence on the joining result. When considering the suitability for joining with regard to the formability of the materials, the influence of the preforming steps must be taken into account. The influences of strain hardening and sheet thickness on the joining properties must be investigated. In this context, a Finite Element Method (FEM) based metamodel analysis of the clinching process was carried out in [1] to investigate the robustness of the clinching process with respect to the different material pre-strains. In [2], the method was extended to the load bearing simulation.Procedure. The metamodel from preliminary work based on various FE models, which predicts the load-bearing capacity of a clinched joint influenced by pre-straining, is compared here with experimental data and the accuracy of the metamodel prediction is discussed. For this purpose an experimental procedure was further develop which allows the preforming of metal sheets from which joining specimens can be separated with a certain degree of unidirectional deformation. In the study, the procedure for preparing the joint specimens and the results of the loading tests are presented. Different possible relevant pre-strain combinations are investigated and compared with the simulation results, to validate the FE models and choose suitable metamodel.}}, author = {{Bielak, Christian Roman and Böhnke, Max and Bobbert, Mathias and Meschut, Gerson}}, issn = {{1662-9795}}, journal = {{Key Engineering Materials}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, pages = {{1516--1526}}, publisher = {{Trans Tech Publications, Ltd.}}, title = {{{Experimental and Numerical Investigation on Manufacturing-Induced Pre-Strain on the Load-Bearing Capacity of Clinched Joints}}}, doi = {{10.4028/p-5d009y}}, volume = {{926}}, year = {{2022}}, } @inbook{33003, author = {{Böhnke, Max and Bielak, Christian Roman and Bobbert, Mathias and Meschut, Gerson}}, booktitle = {{The Minerals, Metals & Materials Series}}, isbn = {{9783031062117}}, issn = {{2367-1181}}, location = {{Toronto, Kanada}}, publisher = {{Springer International Publishing}}, title = {{{Development of a Modified Punch Test for Investigating the Failure Behavior in Sheet Metal Materials}}}, doi = {{10.1007/978-3-031-06212-4_52}}, year = {{2022}}, } @article{34572, author = {{Böhnke, Max and Bielak, Christian Roman and Bobbert, Mathias and Meschut, Gerson}}, journal = {{Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications}}, publisher = {{SAGE Journals}}, title = {{{Experimental and numerical investigation of the influence of multiaxial loading conditions on the failure behavior of clinched joints}}}, doi = {{10.1177/14644207221145886}}, year = {{2022}}, } @article{30100, abstract = {{Since the application of mechanical joining methods, such as clinching or riveting, offers a robust solution for the generation of advanced multi-material connections, the use in the field of lightweight designs (e.g. automotive industry) is steadily increasing. Therefore, not only the design of an individual joint is required but also the dimensioning of the entire joining connection is crucial. However, in comparison to thermal joining techniques, such as spot welding, the evaluation of the joints’ resistance against defined requirements (e.g. types of load, minimal amount of load cycles) mainly relies on the consideration of expert knowledge, a few design principles and a small amount of experimental data. Since this generally implies the involvement of several domains, such as the material characterization or the part design, a tremendous amount of data and knowledge is separately generated for a certain dimensioning process. Nevertheless, the lack of formalization and standardization in representing the gained knowledge leads to a difficult and inconsistent reuse, sharing or searching of already existing information. Thus, this contribution presents a specific ontology for the provision of cross-domain knowledge about mechanical joining processes and highlights two potential use cases of this ontology in the design of clinched and pin joints.}}, author = {{Zirngibl, Christoph and Kügler, Patricia and Popp, Julian and Bielak, Christian Roman and Bobbert, Mathias and Drummer, Dietmar and Meschut, Gerson and Wartzack, Sandro and Schleich, Benjamin}}, issn = {{0944-6524}}, journal = {{Production Engineering}}, keywords = {{Industrial and Manufacturing Engineering, Mechanical Engineering}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Provision of cross-domain knowledge in mechanical joining using ontologies}}}, doi = {{10.1007/s11740-022-01117-y}}, year = {{2022}}, } @inbook{34210, abstract = {{The application of the mechanical joining process clinching enables the joining of sheet metals with a wide range of material-thickness configurations, which is of interest in lightweight construction of multi-material structures. Each material-thickness combination results in a joint with its own property profile that is affected differently by variations. Manufacturing process-related effects from preforming steps influence the geometric shape of a clinched joint as well as its load-bearing capacity. During the clinching process high degrees of plastic strain, increased temperatures and high strain rates occur. In this context, a 3D numerical model was developed which can represent the material-specific behaviour during the process chain steps sheet metal forming, joining, and loading phase in order to achieve a high predictive accuracy of the simulation. Besides to the investigation of the prediction accuracy, the extent of the influence of individual modelling aspects such as temperature and strain rate dependency is examined.}}, author = {{Bielak, Christian Roman and Böhnke, Max and Bobbert, Mathias and Meschut, Gerson}}, booktitle = {{The Minerals, Metals & Materials Series}}, isbn = {{9783031062117}}, issn = {{2367-1181}}, publisher = {{Springer International Publishing}}, title = {{{Development of a Numerical 3D Model for Analyzing Clinched Joints in Versatile Process Chains}}}, doi = {{10.1007/978-3-031-06212-4_15}}, year = {{2022}}, } @article{30962, abstract = {{ Clinching as a mechanical joining process has become established in many areas of car body. In order to predict relevant properties of clinched joints and to ensure the reliability of the process, it is numerically simulated during the product development process. The prediction accuracy of the simulated process depends on the implemented friction model. Therefore, a new method for determining friction coefficients in sheet metal materials was developed and tested. The aim of this study is the numerical investigation of this experimental method by means of FE simulation. The experimental setup is modelled in a 3D numerical simulation taking into account the process parameters varying in the experiment, such as geometric properties, contact pressure and contact velocity. Furthermore, the contact description of the model is calibrated via the experimentally determined friction coefficients according to clinch-relevant parameter space. It is shown that the assumptions made in the determination of the experimental data in preliminary work are valid. In addition, it is investigated to what extent the standard Coulomb friction model in the FEM can reproduce the results of the experimental method. }}, author = {{Bielak, Christian Roman and Böhnke, Max 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}}, keywords = {{Mechanical Engineering, General Materials Science}}, publisher = {{SAGE Publications}}, title = {{{Numerical investigation of a friction test to determine the friction coefficients for the clinching process}}}, doi = {{10.1177/14644207221093468}}, year = {{2022}}, } @article{30963, abstract = {{AbstractIn this paper, a study based on experimental and numerical simulations is performed to analyze fatigue cracks in clinched joints. An experimental investigation is conducted to determine the failure modes of clinched joints under cyclic loading at different load amplitudes with single-lap shear tests. In addition, numerical FEM simulations of clinching process and subsequent shear loading are performed to support the experimental investigations by analyzing the state of stresses at the location of failure. An attempt is made to explain the location of crack initiation in the experiments using evaluation variables such as contact shear stress and maximum principal stress.}}, author = {{Ewenz, Lars and Bielak, Christian Roman and Otroshi, Mortaza and Bobbert, Mathias and Meschut, Gerson and Zimmermann, Martina}}, issn = {{0944-6524}}, journal = {{Production Engineering}}, keywords = {{Industrial and Manufacturing Engineering, Mechanical Engineering}}, number = {{2-3}}, pages = {{305--313}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Numerical and experimental identification of fatigue crack initiation sites in clinched joints}}}, doi = {{10.1007/s11740-022-01124-z}}, volume = {{16}}, year = {{2022}}, } @article{34069, author = {{Schramm, Britta and Martin, Sven and Steinfelder, Christian and Bielak, Christian Roman and Brosius, Alexander and Meschut, Gerson and Tröster, Thomas and Wallmersperger, Thomas and Mergheim, Julia}}, issn = {{2666-3309}}, journal = {{Journal of Advanced Joining Processes}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Engineering (miscellaneous), Chemical Engineering (miscellaneous)}}, publisher = {{Elsevier BV}}, title = {{{A Review on the Modeling of the Clinching Process Chain - Part I: Design Phase}}}, doi = {{10.1016/j.jajp.2022.100133}}, volume = {{6}}, year = {{2022}}, } @article{34068, author = {{Schramm, Britta and Friedlein, Johannes and Gröger, Benjamin and Bielak, Christian Roman and Bobbert, Mathias and Gude, Maik and Meschut, Gerson and Wallmersperger, Thomas and Mergheim, Julia}}, issn = {{2666-3309}}, journal = {{Journal of Advanced Joining Processes}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Engineering (miscellaneous), Chemical Engineering (miscellaneous)}}, publisher = {{Elsevier BV}}, title = {{{A Review on the Modeling of the Clinching Process Chain - Part II: Joining Process}}}, doi = {{10.1016/j.jajp.2022.100134}}, year = {{2022}}, } @article{29951, abstract = {{The components of a body in white consist of many individual thin-walled sheet metal parts, which usually are manufactured in deep-drawing processes. In general, the conditions in a deep-drawing process change due to changing tribology conditions, varying degrees of spring back, or scattering material properties in the sheet blanks, which affects the resulting pre-strain. Mechanical joining processes, especially clinching, are influenced by these process-related pre-strains. The final geometric shape of a clinched joint is affected to a significant level by the prior material deformation when joining with constant process parameters. That leads to a change in the stiffness and force transmission in the clinched joint due to the different geometric dimensions, such as interlock, neck thickness and bottom thickness, which directly affect the load bearing capacity. Here, the influence of the pre-straining in the deep drawing process on the force distribution in clinch points in an automotive assembly is investigated by finite-element models numerically. In further studies, the results are implemented in an optimization tool for designing clinched components. The methodology starts with a pre-straining of metal sheets. This step is followed by 2D rotationally symmetric forming simulations of the joining process. The resulting mesh of each forming simulation is rotated and 3D models are obtained. The clinched joint solid model with pre-strains is used further to determine the joint stiffnesses. With the simulation of the same test set-up with an equivalent point-connector model, the equivalent stiffness for each pre-strain combination is determined. Simulations are performed on a clinched component to assess the influence of pre-strain and sheet thinning on the clinched joint loadings by using the equivalent stiffnesses. The investigations clearly show that for the selected component, the loadings at the clinch points are dependent on the sheet thinning and the stiffnesses due to pre-strain. The magnitude of the influence varies depending on the quantity considered. For example, the shear force is more sensitive to the joint stiffness than to the sheet thinning.}}, author = {{Martin, Sven and Bielak, Christian Roman and Bobbert, Mathias and Tröster, Thomas and Meschut, Gerson}}, issn = {{0944-6524}}, journal = {{Production Engineering}}, keywords = {{Industrial and Manufacturing Engineering, Mechanical Engineering}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Numerical investigation of the clinched joint loadings considering the initial pre-strain in the joining area}}}, doi = {{10.1007/s11740-021-01103-w}}, year = {{2022}}, } @article{31828, author = {{Kupfer, Robert and Köhler, Daniel and Römisch, David and Wituschek, Simon and Ewenz, Lars and Kalich, Jan and Weiß, Deborah and Sadeghian, Behdad and Busch, Matthias and Krüger, Jan and Neuser, Moritz and Grydin, Olexandr and Böhnke, Max and Bielak, Christian Roman and Troschitz, Juliane}}, issn = {{2666-3309}}, journal = {{Journal of Advanced Joining Processes}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Engineering (miscellaneous), Chemical Engineering (miscellaneous)}}, publisher = {{Elsevier BV}}, title = {{{Clinching of Aluminum Materials – Methods for the Continuous Characterization of Process, Microstructure and Properties}}}, doi = {{10.1016/j.jajp.2022.100108}}, volume = {{5}}, year = {{2022}}, } @article{34215, abstract = {{Clinching as a mechanical joining technique allows a fast and reliable joining of metal sheets in large-scale production. An efficient design and dimensioning of clinched joints requires a holistic understanding of the material, the joining process and the resulting properties of the joint. In this paper, the process chain for clinching metal sheets is described and experimental techniques are proposed to analyze the process-microstructure-property relationships from the sheet metal to the joined structure. At the example of clinching aluminum EN AW 6014, characterization methods are applied and discussed for the following characteristics: the mechanical properties of the sheet materials, the tribological behavior in the joining system, the joining process and the resulting material structure, the load-bearing behavior of the joint, the damage and degradation as well as the service life and crack growth behavior. The compilation of the characterization methods gives an overview on the advantages and weaknesses of the methods and the multiple interactions of material, process and properties during clinching. In addition, the results of the analyses on EN AW 6014 can be applied for parameterization and validation of simulations.}}, author = {{Kupfer, Robert and Köhler, Daniel and Römisch, David and Wituschek, Simon and Ewenz, Lars and Kalich, Jan and Weiß, Deborah and Sadeghian, Behdad and Busch, Matthias and Krüger, Jan Tobias and Neuser, Moritz and Grydin, Olexandr and Böhnke, Max and Bielak, Christian Roman and Troschitz, Juliane}}, issn = {{2666-3309}}, journal = {{Journal of Advanced Joining Processes}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Engineering (miscellaneous), Chemical Engineering (miscellaneous)}}, publisher = {{Elsevier BV}}, title = {{{Clinching of Aluminum Materials – Methods for the Continuous Characterization of Process, Microstructure and Properties}}}, doi = {{10.1016/j.jajp.2022.100108}}, volume = {{5}}, year = {{2022}}, } @inproceedings{20807, author = {{Bielak, Christian Roman and Böhnke, Max and Bobbert, Mathias and Meschut, Gerson}}, location = {{Lüttich}}, title = {{{Further development of a numerical method for analyzing the load capacity of clinched joints in versatile process chains}}}, doi = {{10.25518/esaform21.4298}}, year = {{2021}}, } @article{21810, author = {{Otroshi, Mortaza and Meschut, Gerson and Bielak, Christian Roman and Masendorf, Lukas and Esderts, Alfons}}, issn = {{1662-9795}}, journal = {{Key Engineering Materials}}, pages = {{35--40}}, publisher = {{Trans Tech Publications Ltd}}, title = {{{Modeling of Stiffness Anisotropy in Simulation of Self-Piercing Riveted Components}}}, doi = {{https://doi.org/10.4028/www.scientific.net/KEM.883.35}}, volume = {{883}}, year = {{2021}}, } @article{25556, abstract = {{AbstractIn order to reduce fuel consumption and thus pollutant emissions, the automotive industry is increasingly developing lightweight construction concepts that are accompanied by an increasing usage of aluminum materials. Due to poor weldability of aluminum in combination with other materials, mechanical joining methods such as clinching were developed and established in series production. In order to predict the relevant characteristics of clinched joints and to ensure the reliability of the process, it is simulated numerically during product development processes. In this regard, the predictive accuracy of the simulated process highly depends on the implemented friction model. In particular, the frictional behavior between the sheet metals as well as between the sheet metal and clinching tools has a significant impact on the geometrical formation of the clinched joint. No testing methods exist that can sufficiently investigate the frictional behavior in sheet materials, especially under high interface pressures, different relative velocities, and long friction paths, while allowing a decoupled consideration of the test parameters. This paper describes the development of further testing concepts based on a proven tribo-torsion test method for determining friction coefficients between sheet metal materials for the simulation of clinching processes. For this purpose, the correlation of interface pressure and the relative velocity between aluminum and steel sheet material in clinching processes is investigated using numerical simulation. Based on these findings, the developed concepts focus on determining friction coefficients at interface pressures of the above materials, yield stress, as well as the reproduction of the occurring friction conditions between sheet metal materials and tool surfaces in clinching processes using tool substitutes. Furthermore, wear investigations between sheet metal material and tool surface were carried out in the friction tests with subsequent EDX analyses of the frictioned tool surfaces. The developed method also allows an optical deformation measurement of the sheet metal material specimen by means of digital image correlation (DIC). Based on a methodological approach, the test setups and the test systems used are explained, and the functionality of the concepts is proven by experimental tests using different sheet metal materials.}}, author = {{Böhnke, Max and Rossel, Moritz Sebastian and Bielak, Christian Roman and Bobbert, Mathias and Meschut, Gerson}}, issn = {{0268-3768}}, journal = {{The International Journal of Advanced Manufacturing Technology}}, title = {{{Concept development of a method for identifying friction coefficients for the numerical simulation of clinching processes}}}, doi = {{10.1007/s00170-021-07986-4}}, year = {{2021}}, } @article{34227, abstract = {{In order to reduce the fuel consumption and consequently the greenhouse emissions, the automotive industry is implementing lightweight constructions in the body in white production. As a result, the use of aluminum alloys is continuously increasing. Due to poor weldability of aluminum in combination with other materials, mechanical joining technologies like clinching are increasingly used. In order to predict relevant characteristics of clinched joints and to ensure the reliability of the process, it is simulated numerically during product development processes. In this regard the predictive accuracy of the simulated process highly depends on the implemented friction model. In particular, the frictional behavior between the sheet metals affects the geometrical formation of the clinched joint significantly. This paper presents a testing method, which enables to determine the frictional coefficients between sheet metal materials for the simulation of clinching processes. For this purpose, the correlation of interface pressure and the relative velocity between aluminum sheets in clinching processes is investigated using numerical simulation. Furthermore, the developed testing method focuses on the specimen geometry as well as the reproduction of the occurring friction conditions between two sheet metal materials in clinching processes. Based on a methodical approach the test setup is explained and the functionality of the method is proven by experimental tests using sheet metal material EN AW6014.}}, author = {{Rossel, Moritz Sebastian and Böhnke, Max and Bielak, Christian Roman and Bobbert, Mathias and Meschut, Gerson}}, issn = {{1662-9795}}, journal = {{Key Engineering Materials}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, pages = {{81--88}}, publisher = {{Trans Tech Publications, Ltd.}}, title = {{{Development of a Method for the Identification of Friction Coefficients in Sheet Metal Materials for the Numerical Simulation of Clinching Processes}}}, doi = {{10.4028/www.scientific.net/kem.883.81}}, volume = {{883}}, 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}}, } @inproceedings{21811, abstract = {{In order to reduce the fuel consumption and consequently the greenhouse emissions, the automotive industry is implementing lightweight constructions in the body in white production. As a result, the use of aluminum alloys is continuously increasing. Due to poor weldability of aluminum in combination with other materials, mechanical joining technologies like clinching are increasingly used. In order to predict relevant characteristics of clinched joints and to ensure the reliability of the process, it is simulated numerically during product development processes. In this regard the predictive accuracy of the simulated process highly depends on the implemented friction model. In particular, the frictional behavior between the sheet metals affects the geometrical formation of the clinched joint significantly. This paper presents a testing method, which enables to determine the frictional coefficients between sheet metal materials for the simulation of clinching processes. For this purpose, the correlation of interface pressure and the relative velocity between aluminum sheets in clinching processes is investigated using numerical simulation. Furthermore, the developed testing method focuses on the specimen geometry as well as the reproduction of the occurring friction conditions between two sheet metal materials in clinching processes. Based on a methodical approach the test setup is explained and the functionality of the method is proven by experimental tests using sheet metal material EN AW6014. }}, author = {{Rossel, Moritz Sebastian and Böhnke, Max and Bielak, Christian Roman and Bobbert, Mathias and Meschut, Gerson}}, booktitle = {{Sheet Metal 2021}}, keywords = {{Tribology, Sheet Metal, Simulation}}, pages = {{81--88}}, publisher = {{Trans Tech Publications Ltd}}, title = {{{Development of a Method for the Identification of Friction Coefficients in Sheet Metal Materials for the Numerical Simulation of Clinching Processes}}}, doi = {{10.4028/www.scientific.net/KEM.883.81}}, volume = {{883}}, year = {{2021}}, } @article{20678, author = {{Bielak, Christian Roman and Böhnke, Max and Beck, Robert and Bobbert, Mathias and Meschut, Gerson}}, journal = {{Journal of Advanced Joining Processes. }}, keywords = {{Clinching, process simulation, FEM, pre-straining, sensitivity analysis}}, publisher = {{Elsevier}}, title = {{{Numerical analysis of the robustness of clinching process considering the pre-forming of the parts }}}, doi = {{https://doi.org/10.1016/j.jajp.2020.100038}}, year = {{2020}}, } @inproceedings{20344, author = {{Bielak, Christian Roman and Böhnke, Max and Bobbert, Mathias and Meschut, Gerson}}, location = {{Darmstadt}}, title = {{{Development of a numerical method for analyzing the robustness of clinching in versatile process chains}}}, year = {{2020}}, }