TY - CONF AB - 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. AU - Bielak, Christian Roman AU - Böhnke, Max AU - Friedlein, Johannes AU - Bobbert, Mathias AU - Mergheim, Julia AU - Steinmann, Paul AU - Meschut, Gerson ID - 43090 SN - 2474-395X T2 - Materials Research Proceedings TI - Numerical analysis of failure modeling in clinching process chain simulation ER - TY - CONF AB - 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. AU - Böhnke, Max AU - Bielak, Christian Roman AU - Friedlein, Johannes AU - Bobbert, Mathias AU - Mergheim, Julia AU - Steinmann, Paul AU - Meschut, Gerson ID - 43462 SN - 2474-395X T2 - Materials Research Proceedings TI - A calibration method for failure modeling in clinching process simulations ER - TY - CHAP AU - Böhnke, Max AU - Bielak, Christian Roman AU - Bobbert, Mathias AU - Meschut, Gerson ID - 52454 SN - 2195-4356 T2 - Lecture Notes in Mechanical Engineering TI - Experimental and Numerical Investigation of Clinched Joints Under Shear Tensile Loading at High Strain Rates ER - TY - CONF AU - Friedlein, Johannes AU - Bielak, Christian Roman AU - Böhnke, Max AU - Bobbert, Mathias AU - Mergheim, Julia AU - Steinmann, Paul AU - Meschut, Gerson ID - 43463 T2 - Materials Research Proceedings TI - Influence of plastic orthotropy on clinching of sheet metal ER - TY - CHAP AU - Bielak, Christian Roman AU - Böhnke, Max AU - Bobbert, Mathias AU - Meschut, Gerson ID - 52614 SN - 2195-4356 T2 - Lecture Notes in Mechanical Engineering TI - Numerical Investigation of the Coupled Friction Behavior in the Clinching Process Chain ER - TY - JOUR AB - 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. AU - Ewenz, L. AU - Bielak, Christian Roman AU - Otroshi, Mortaza AU - Bobbert, Mathias AU - Meschut, Gerson AU - Zimmermann, M. ID - 34213 IS - 2-3 JF - Production Engineering KW - Industrial and Manufacturing Engineering KW - Mechanical Engineering SN - 0944-6524 TI - Numerical and experimental identification of fatigue crack initiation sites in clinched joints VL - 16 ER - TY - JOUR AB - 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. AU - Bielak, Christian Roman AU - Böhnke, Max AU - Bobbert, Mathias AU - Meschut, Gerson ID - 32413 JF - Key Engineering Materials KW - Mechanical Engineering KW - Mechanics of Materials KW - General Materials Science SN - 1662-9795 TI - Experimental and Numerical Investigation on Manufacturing-Induced Pre-Strain on the Load-Bearing Capacity of Clinched Joints VL - 926 ER - TY - CHAP AU - Böhnke, Max AU - Bielak, Christian Roman AU - Bobbert, Mathias AU - Meschut, Gerson ID - 33003 SN - 2367-1181 T2 - The Minerals, Metals & Materials Series TI - Development of a Modified Punch Test for Investigating the Failure Behavior in Sheet Metal Materials ER - TY - JOUR AU - Böhnke, Max AU - Bielak, Christian Roman AU - Bobbert, Mathias AU - Meschut, Gerson ID - 34572 JF - Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications TI - Experimental and numerical investigation of the influence of multiaxial loading conditions on the failure behavior of clinched joints ER - TY - JOUR AB - 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. AU - Zirngibl, Christoph AU - Kügler, Patricia AU - Popp, Julian AU - Bielak, Christian Roman AU - Bobbert, Mathias AU - Drummer, Dietmar AU - Meschut, Gerson AU - Wartzack, Sandro AU - Schleich, Benjamin ID - 30100 JF - Production Engineering KW - Industrial and Manufacturing Engineering KW - Mechanical Engineering SN - 0944-6524 TI - Provision of cross-domain knowledge in mechanical joining using ontologies ER - TY - CHAP AB - 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. AU - Bielak, Christian Roman AU - Böhnke, Max AU - Bobbert, Mathias AU - Meschut, Gerson ID - 34210 SN - 2367-1181 T2 - The Minerals, Metals & Materials Series TI - Development of a Numerical 3D Model for Analyzing Clinched Joints in Versatile Process Chains ER - TY - JOUR AB - 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. AU - Bielak, Christian Roman AU - Böhnke, Max AU - Bobbert, Mathias AU - Meschut, Gerson ID - 30962 JF - Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications KW - Mechanical Engineering KW - General Materials Science SN - 1464-4207 TI - Numerical investigation of a friction test to determine the friction coefficients for the clinching process ER - TY - JOUR AB - 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. AU - Ewenz, Lars AU - Bielak, Christian Roman AU - Otroshi, Mortaza AU - Bobbert, Mathias AU - Meschut, Gerson AU - Zimmermann, Martina ID - 30963 IS - 2-3 JF - Production Engineering KW - Industrial and Manufacturing Engineering KW - Mechanical Engineering SN - 0944-6524 TI - Numerical and experimental identification of fatigue crack initiation sites in clinched joints VL - 16 ER - TY - JOUR AU - Schramm, Britta AU - Martin, Sven AU - Steinfelder, Christian AU - Bielak, Christian Roman AU - Brosius, Alexander AU - Meschut, Gerson AU - Tröster, Thomas AU - Wallmersperger, Thomas AU - Mergheim, Julia ID - 34069 JF - Journal of Advanced Joining Processes KW - Mechanical Engineering KW - Mechanics of Materials KW - Engineering (miscellaneous) KW - Chemical Engineering (miscellaneous) SN - 2666-3309 TI - A Review on the Modeling of the Clinching Process Chain - Part I: Design Phase VL - 6 ER - TY - JOUR AU - Schramm, Britta AU - Friedlein, Johannes AU - Gröger, Benjamin AU - Bielak, Christian Roman AU - Bobbert, Mathias AU - Gude, Maik AU - Meschut, Gerson AU - Wallmersperger, Thomas AU - Mergheim, Julia ID - 34068 JF - Journal of Advanced Joining Processes KW - Mechanical Engineering KW - Mechanics of Materials KW - Engineering (miscellaneous) KW - Chemical Engineering (miscellaneous) SN - 2666-3309 TI - A Review on the Modeling of the Clinching Process Chain - Part II: Joining Process ER - TY - JOUR AB - 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. AU - Martin, Sven AU - Bielak, Christian Roman AU - Bobbert, Mathias AU - Tröster, Thomas AU - Meschut, Gerson ID - 29951 JF - Production Engineering KW - Industrial and Manufacturing Engineering KW - Mechanical Engineering SN - 0944-6524 TI - Numerical investigation of the clinched joint loadings considering the initial pre-strain in the joining area ER - TY - JOUR AU - Kupfer, Robert AU - Köhler, Daniel AU - Römisch, David AU - Wituschek, Simon AU - Ewenz, Lars AU - Kalich, Jan AU - Weiß, Deborah AU - Sadeghian, Behdad AU - Busch, Matthias AU - Krüger, Jan AU - Neuser, Moritz AU - Grydin, Olexandr AU - Böhnke, Max AU - Bielak, Christian Roman AU - Troschitz, Juliane ID - 31828 JF - Journal of Advanced Joining Processes KW - Mechanical Engineering KW - Mechanics of Materials KW - Engineering (miscellaneous) KW - Chemical Engineering (miscellaneous) SN - 2666-3309 TI - Clinching of Aluminum Materials – Methods for the Continuous Characterization of Process, Microstructure and Properties VL - 5 ER - TY - JOUR AB - 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. AU - Kupfer, Robert AU - Köhler, Daniel AU - Römisch, David AU - Wituschek, Simon AU - Ewenz, Lars AU - Kalich, Jan AU - Weiß, Deborah AU - Sadeghian, Behdad AU - Busch, Matthias AU - Krüger, Jan Tobias AU - Neuser, Moritz AU - Grydin, Olexandr AU - Böhnke, Max AU - Bielak, Christian Roman AU - Troschitz, Juliane ID - 34215 JF - Journal of Advanced Joining Processes KW - Mechanical Engineering KW - Mechanics of Materials KW - Engineering (miscellaneous) KW - Chemical Engineering (miscellaneous) SN - 2666-3309 TI - Clinching of Aluminum Materials – Methods for the Continuous Characterization of Process, Microstructure and Properties VL - 5 ER - TY - CONF AU - Bielak, Christian Roman AU - Böhnke, Max AU - Bobbert, Mathias AU - Meschut, Gerson ID - 20807 TI - Further development of a numerical method for analyzing the load capacity of clinched joints in versatile process chains ER - TY - JOUR AU - Otroshi, Mortaza AU - Meschut, Gerson AU - Bielak, Christian Roman AU - Masendorf, Lukas AU - Esderts, Alfons ID - 21810 JF - Key Engineering Materials SN - 1662-9795 TI - Modeling of Stiffness Anisotropy in Simulation of Self-Piercing Riveted Components VL - 883 ER -