A01 - Form­ab­il­ity pre­dic­tion

The use of mechanical joining technology offers the possibility of joining mixed structures with a wide range of requirement profiles and material-geometry combinations. Due to the processes being only partially visible from the outside, the high number of combinable tool variants, and variable force- and displacement-based process parameters, it is not possible to holistically verify the joinability in adaptable process chains along the process steps using a conventional, experimental approach.

The vision of the subproject is therefore to develop methods for the holistic prediction of joining reliability, joining suitability, and joining feasibility along the adaptable process chain. In order to achieve the necessary holistic approach with regard to joining materials, joining processes, and operating conditions, subproject A01 integrates methods already developed by other subprojects of the TRR in addition to developing new methods. Combined methods consisting of experimental testing methods and simulation models that describe the joining behavior based on material behavior are being developed in order to identify fundamental principles of action and enable comprehensive prediction based on simulation. The methods will ultimately be used to develop targeted flexibility and robustness measures for adaptable process chains in response to varying input variables.

In TP A01, a simulation strategy is being developed that virtually maps the process steps of joining part production, joining process, and loading phase and allows the transfer of relevant state variables, such as geometry, material hardening, and damage, for a continuous simulation of mechanical joinability. The simulation model will be used in an iterative process to investigate the utility value and sensitivity of the transferred state variables with regard to the overall process and the subsequent process steps. To validate the simulation models, the entire process chain will be traced in detail experimentally, with the geometry and material state after each process step and the process variables being determined as locally as possible. This requires the development of new test methods for characterizing the friction properties and damage behavior of joining materials under the complex boundary conditions of the process chain. In addition, suitable sample shapes must be developed that can pass through the entire process chain and enable targeted adjustment of the material state during joining part production in the joining zone as well as combined load conditions.

Methodological approach and work program

TRR 285 - Subproject A01

Duration: 2019 - 2027

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Özcan Harabati, M.Sc.

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Prof. Dr.-Ing. Gerson Meschut

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Malte Christian Schlichter, M.Sc.

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Jean-Patrick Ludwig, M.Sc.

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Pub­lic­a­tions

Numerical analysis of the robustness of clinching process considering the pre-forming of the parts

C.R. Bielak, M. Böhnke, R. Beck, M. Bobbert, G. Meschut, Journal of Advanced Joining Processes. (2020).

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Development of a numerical method for analyzing the robustness of clinching in versatile process chains

C.R. Bielak, M. Böhnke, M. Bobbert, G. Meschut, in: Material Science and Engineering Congress - MSE 2020, n.d.

PDF In many areas of product manufacturing individual components are usually joined together to form complex structures with numerous joints. Mechanical joining technology offers the possibility of joining structures with a wide range of material-geometry combinations. In order to realize the increasing number of varying products using different materials and designs within a process chain, they need to be versatile. Due to changing properties of the materials to be joined, tool geometries and process variables in mechanical joining processes, especially clinching, must be continuously adapted which results in a limited versatility of the process. In this regard, it is necessary to examine the robustness of the clinching process in versatile process chains. Therefore, a method is developed which describes the joint characteristics based on the material properties in order to enable the investigation of the clinching process regarding the robustness concerning continuously changing process and material conditions. The predictive accuracy of numerical simulations for mechanical joining processes depends on the implemented material model, especially the plasticity of the joining parts. Therefore, experimental material characterization processes are used to determine material properties. Furthermore, clinched joints in different material combinations are experimentally generated and examined. Based on these investigations a simulation model of the joining process is developed as 2D-Clinching FEM model in LS-Dyna. The Validation of the developed simulation model is ensured by comparing the geometric formation of the joint and force-displacement curves of the joining process with experimental generated joints. By combining the simulation model with an optimization tool (LS-OPT) the influence of different parameters on the joint characteristics is determined and the robustness of the joining process in versatile process chains is investigated.

Further development of a numerical method for analyzing the load capacity of clinched joints in versatile process chains

C.R. Bielak, M. Böhnke, M. Bobbert, G. Meschut, in: ESAFORM 2021, n.d.

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Concept development of a method for identifying friction coefficients for the numerical simulation of clinching processes

M. Böhnke, M.S. Rossel, C.R. Bielak, M. Bobbert, G. Meschut, The International Journal of Advanced Manufacturing Technology (2021).

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Development of a Method for the Identification of Friction Coefficients in Sheet Metal Materials for the Numerical Simulation of Clinching Processes

M.S. Rossel, M. Böhnke, C.R. Bielak, M. Bobbert, G. Meschut, Key Engineering Materials 883 (2021) 81–88.

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Influence of rivet length on joint formation on self-piercing riveting process considering further process parameters

F. Kappe, C.R. Bielak, V. Sartisson, M. Bobbert, G. Meschut, in: ESAFORM 2021, University of Liege, 2021.

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Influence of various procedures for the determination of flow curves on the predictive accuracy of numerical simulations for mechanical joining processes

M. Böhnke, F. Kappe, M. Bobbert, G. Meschut, Materials Testing 63 (2021) 493–500.

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Numerical and experimental identification of fatigue crack initiation sites in clinched joints

L. Ewenz, C.R. Bielak, M. Otroshi, M. Bobbert, G. Meschut, M. Zimmermann, Production Engineering 16 (2022) 305–313.

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Influence of heat treatment on the suitability for clinching of the aluminium casting alloy AlSi9

M. Neuser, M. Böhnke, O. Grydin, M. Bobbert, M. Schaper, G. Meschut, Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications (2022).

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Clinching of Aluminum Materials – Methods for the Continuous Characterization of Process, Microstructure and Properties

R. Kupfer, D. Köhler, D. Römisch, S. Wituschek, L. Ewenz, J. Kalich, D. Weiß, B. Sadeghian, M. Busch, J.T. Krüger, M. Neuser, O. Grydin, M. Böhnke, C.R. Bielak, J. Troschitz, Journal of Advanced Joining Processes 5 (2022).

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Functionality Study of an Optical Measurement Concept for Local Force Signal Determination in High Strain Rate Tensile Tests

M. Böhnke, E. Unruh, S. Sell, M. Bobbert, D. Hein, G. Meschut, Key Engineering Materials 926 (2022) 1564–1572.

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Development of a Modified Punch Test for Investigating the Failure Behavior in Sheet Metal Materials

M. Böhnke, C.R. Bielak, M. Bobbert, G. Meschut, in: The Minerals, Metals & Materials Series, Springer International Publishing, Cham, 2022.

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Experimental and numerical investigation of the influence of multiaxial loading conditions on the failure behavior of clinched joints

M. Böhnke, C.R. Bielak, M. Bobbert, G. Meschut, Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications (2022).

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Review on mechanical joining by plastic deformation

G. Meschut, M. Merklein, A. Brosius, D. Drummer, L. Fratini, U. Füssel, M. Gude, W. Homberg, P.A.F. Martins, M. Bobbert, M. Lechner, R. Kupfer, B. Gröger, D. Han, J. Kalich, F. Kappe, T. Kleffel, D. Köhler, C.-M. Kuball, J. Popp, D. Römisch, J. Troschitz, C. Wischer, S. Wituschek, M. Wolf, Journal of Advanced Joining Processes 5 (2022).

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Provision of cross-domain knowledge in mechanical joining using ontologies

C. Zirngibl, P. Kügler, J. Popp, C.R. Bielak, M. Bobbert, D. Drummer, G. Meschut, S. Wartzack, B. Schleich, Production Engineering (2022).

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Development of a Numerical 3D Model for Analyzing Clinched Joints in Versatile Process Chains

C.R. Bielak, M. Böhnke, M. Bobbert, G. Meschut, in: The Minerals, Metals & Materials Series, Springer International Publishing, Cham, 2022.

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Numerical investigation of a friction test to determine the friction coefficients for the clinching process

C.R. Bielak, M. Böhnke, M. Bobbert, G. Meschut, Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications (2022).

DOI

Numerical and experimental identification of fatigue crack initiation sites in clinched joints

L. Ewenz, C.R. Bielak, M. Otroshi, M. Bobbert, G. Meschut, M. Zimmermann, Production Engineering 16 (2022) 305–313.

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A Review on the Modeling of the Clinching Process Chain - Part I: Design Phase

B. Schramm, S. Martin, C. Steinfelder, C.R. Bielak, A. Brosius, G. Meschut, T. Tröster, T. Wallmersperger, J. Mergheim, Journal of Advanced Joining Processes 6 (2022).

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A Review on the Modeling of the Clinching Process Chain - Part II: Joining Process

B. Schramm, J. Friedlein, B. Gröger, C.R. Bielak, M. Bobbert, M. Gude, G. Meschut, T. Wallmersperger, J. Mergheim, Journal of Advanced Joining Processes (2022).

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Numerical investigation of the clinched joint loadings considering the initial pre-strain in the joining area

S. Martin, C.R. Bielak, M. Bobbert, T. Tröster, G. Meschut, Production Engineering (2022).

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Numerical analysis of failure modeling in clinching process chain simulation

C.R. Bielak, M. Böhnke, J. Friedlein, M. Bobbert, J. Mergheim, P. Steinmann, G. Meschut, in: Materials Research Proceedings, Materials Research Forum LLC, 2023.

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A calibration method for failure modeling in clinching process simulations

M. Böhnke, C.R. Bielak, J. Friedlein, M. Bobbert, J. Mergheim, P. Steinmann, G. Meschut, in: Materials Research Proceedings, Materials Research Forum LLC, 2023.

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Experimental and Numerical Investigation of Clinched Joints Under Shear Tensile Loading at High Strain Rates

M. Böhnke, C.R. Bielak, M. Bobbert, G. Meschut, in: Lecture Notes in Mechanical Engineering, Springer Nature Switzerland, Cham, 2023.

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Influence of plastic orthotropy on clinching of sheet metal

J. Friedlein, C.R. Bielak, M. Böhnke, M. Bobbert, J. Mergheim, P. Steinmann, G. Meschut, in: Materials Research Proceedings, Materials Research Forum LLC, 2023.

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Development of a friction model for the numerical simulation of clinching processes

M. Böhnke, C.R. Bielak, R. Beck, M. Bobbert, G. Meschut, Friction (2024).

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Material Parameter Identification for a Stress-State-Dependent Ductile Damage and Failure Model Applied to Clinch Joining

J. Friedlein, M. Böhnke, M.C. Schlichter, M. Bobbert, G. Meschut, J. Mergheim, P. Steinmann, Journal of Manufacturing and Materials Processing 8 (2024).

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Mechanical joinability of microstructurally graded structural components manufactured from hypoeutectic aluminium casting alloys

M. Neuser, M.C. Schlichter, K.-P. Hoyer, M. Bobbert, G. Meschut, M. Schaper, 44th Conference of the International Deep Drawing Research Group (IDDRG 2025) 408 (2025).

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Experimental and numerical investigation of the influence of rolling-induced sheet metal deformation on SPR joints

M.C. Schlichter, Ö. Harabati, J.-P. Ludwig, M. Böhnke, C.R. Bielak, M. Bobbert, G. Meschut, in: Materials Research Proceedings, Materials Research Forum LLC, Paestum, 2025.

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Experimental and numerical investigation of the influence of rolling-induced sheet metal deformation on SPR joints

M.C. Schlichter, Ö. Harabati, J.-P. Ludwig, M. Böhnke, C.R. Bielak, M. Bobbert, G. Meschut, in: Materials Research Proceedings, Materials Research Forum LLC, 2025.

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Investigation on manufacturing-induced pre-deformation on the fatigue behaviour of clinched joints

M.C. Schlichter, Ö. Harabati, M. Böhnke, C.R. Bielak, M. Bobbert, G. Meschut, in: Materials Research Proceedings, Materials Research Forum LLC, 2025.

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High-cycle fatigue testing and parameter identification for numerical simulation of aluminum alloy EN AW-6014

C. Chen, M.C. Schlichter, S. Harzheim, M. Hofmann, M. Bobbert, G. Meschut, T. Wallmersperger, in: Materials Research Proceedings, Materials Research Forum LLC, 2025.

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Cross-process damage modeling: A process-chain case study of clinching and self-pierced riveting for aluminum connections

Ö. Harabati, C.R. Bielak, M. Böhnke, M.C. Schlichter, M. Brockmeier, M. Bobbert, G. Meschut, in: Materials Research Proceedings, Materials Research Forum LLC, 2025.

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Application of stress-state-dependent ductile damage and failure model to clinch joining for a wide range of tool and material combinations

J. Friedlein, S. Lüder, J. Kalich, H.C. Schmale, M. Böhnke, M.C. Schlichter, M. Bobbert, G. Meschut, P. Steinmann, J. Mergheim, Journal of Advanced Joining Processes 11 (2025).

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Simulation of the joining process of graded hardened multi-range capable rivets

P.K. Holtkamp, C.R. Bielak, M. Bobbert, G. Meschut, in: Materials Research Proceedings, Materials Research Forum LLC, 2025.

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LOCAL DEFORMATION AND FAILURE OF COMPOSITES DURING SELF-PIERCING RIVETING: A CT BASED MICROSTRUCTURE INVESTIGATION

A. Dargel, B. Gröger, M.C. Schlichter, J. Gerritzen, D. Köhler, G. Meschut, M. Gude, R. Kupfer, in: J.F.S. Gomes, S.A. Meguid (Eds.), Proceedings of the 8th International Conference on Integrity-Reliability-Failure (IRF2025), FEUP, Porto, 2025.

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Numerical analysis of the robustness of self-pierce riveting with pre-formed joining partners

J.-P. Ludwig, E. Tolke, M.C. Schlichter, M. Bobbert, G. Meschut, Journal of Advanced Joining Processes 13 (2026).

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