@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}},
}
@book{21800,
author = {{Sander, Sascha and Bobbert, Mathias and Meschut, Gerson}},
isbn = {{978-3-662-62832-4}},
pages = {{332}},
publisher = {{Springer Vieweg}},
title = {{{Intrinsische Hybridverbunde für Leichtbautragstrukturen}}},
year = {{2021}},
}
@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}},
}
@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{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}},
}
@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}},
}
@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}},
}
@inbook{29086,
author = {{Drossel, Welf-G and Bobbert, Mathias and Böhme, Marcus and Dammann, Christian and Dittes, Axel and Gießmann, Mina and Hühne, Christian and Ihlemann, Jörn and Kießling, Robert and Lampke, Thomas and Lenz, Peter and Mahnken, Rolf and Meschut, Gerson and Müller, Roland and Nier, Matthias and Prussak, Robert and Riemer, Matthias and Sander, Sascha and Schaper, Mirko and Scharf, Ingolf and Scholze, Mario and Schwöbel, Stephan-Daniel and Sharafiev, Semen and Sinapius, Michael and Stefaniak, Daniel and Tröster, Thomas and Wagner, Martin F. -X. and Wang, Zheng and Zinn, Carolin}},
booktitle = {{Intrinsische Hybridverbunde für Leichtbautragstrukturen}},
isbn = {{9783662628324}},
title = {{{Hybridprofile für Trag- und Crashstrukturen}}},
doi = {{10.1007/978-3-662-62833-1_3}},
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}},
}
@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}},
}
@book{20677,
author = {{Bobbert, Mathias}},
isbn = {{978-3-8440-6787-3}},
title = {{{Untersuchungen zu kontinuums- und bruchmechanischen Methoden für die Prognose des Crashverhaltens toleranzbehafteter Strukturklebverbindungen}}},
year = {{2019}},
}
@article{15958,
author = {{Zinn, Carolin and Bobbert, Mathias and Dammann, Christian and Wang, Zheng and Tröster, Thomas and Mahnken, Rolf and Meschut, Gerson and Schaper, Mirko}},
issn = {{1359-8368}},
journal = {{Composites Part B: Engineering}},
pages = {{173--185}},
title = {{{Shear strength and failure behaviour of laser nano-structured and conventionally pre-treated interfaces in intrinsically manufactured CFRP-steel hybrids}}},
doi = {{10.1016/j.compositesb.2018.05.030}},
year = {{2018}},
}
@article{24557,
author = {{Kießling, R. and Ihlemann, J. and Pohl, M. and Stommel, M. and Dammann, C. and Mahnken, Rolf and Bobbert, Mathias and Meschut, Gerson and Hirsch, F. and Kästner, M.}},
issn = {{0929-189X}},
journal = {{Applied Composite Materials}},
pages = {{251--269}},
title = {{{On the Design, Characterization and Simulation of Hybrid Metal-Composite Interfaces}}},
doi = {{10.1007/s10443-016-9526-z}},
year = {{2016}},
}
@article{42893,
abstract = {{The influences of geometrical parameters like adhesive layer thickness and gap-filling on the mechanical properties of adhesively bonded joints are investigated by means of experimental studies with controlled parameter variations. In addition, corresponding simulation models are used to analyse these effects. As a result, the behaviour of joints under variation of manufacturing parameters can be reproduced with high accuracy. Furthermore, the validated simulation models are used to perform sensitivity analysis on a component-like specimen. Based on these studies, tolerance ranges can be specified and robust design optimisation can be carried out.}},
author = {{Schwarzkopf, G. and Bobbert, Mathias and Teutenberg, Dominik and Meschut, Gerson and Matzenmiller, A.}},
issn = {{2212-8271}},
journal = {{Procedia CIRP}},
keywords = {{General Medicine}},
pages = {{321--326}},
publisher = {{Elsevier BV}},
title = {{{Tolerance Analysis of Adhesive Bonds in Crash Simulation}}},
doi = {{10.1016/j.procir.2016.02.151}},
volume = {{43}},
year = {{2016}},
}
@article{15963,
author = {{Tröster, Thomas and Schaper, Mirko and Meschut, Gerson and Mahnken, Rolf and Bobbert, Mathias and Lauter, Christian and Zinn, Carolin and Wang, Zheng and Dammann, Christian}},
issn = {{2051-8218}},
journal = {{International Journal of Automotive Composites}},
pages = {{272--298}},
title = {{{Influences of interface and surface pretreatment on the mechanical properties of metal-CFRP hybrid structures manufactured by resin transfer moulding}}},
doi = {{10.1504/ijautoc.2016.10005305}},
volume = {{2}},
year = {{2016}},
}
@inproceedings{16265,
author = {{Zinn, C. and Bobbert, Mathias and Dammann, C. and Wang, Z. and Schaper, Mirko and Meschut, Gerson and Mahnken, Rolf and Tröster, Thomas}},
location = {{Kaiserslautern}},
title = {{{Laserbehandlung intrinsisch gefertigter Hybride - strukturelle, mechanische und korrosive Eigenschaften}}},
year = {{2016}},
}