PSI - Issue 73

Martin Krejsa et al. / Procedia Structural Integrity 73 (2025) 81–86 Martin Krejsa, Petr Lehner, Jakub Flodr / Structural Integrity Procedia 00 (2025) 000–000

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2.2. Numerical model The numerical model, created in ANSYS (ANSYS, 2020), corresponded to the full extent of the physical experiment. The model used SOLID186 volume elements with many internal nodes (see Fig. 2). On one side, the specimen was fixed at a length of 100 mm, corresponding to the fixation in the press. On the other side, the specimen was also fixed, but with an additional displacement of the nodes in the direction of movement of the pressmachine. The numerical model was materially, structurally and geometrically non-linear. The aim was to mimic the real specimen as closely as possible to make its behaviour and geometry as close to reality as possible. The material model was multilinear. The load was applied in several steps and a special load condition was created to simulate the slip of the electromechanical press head. The numerical model was conceived as a mathematical model without destruction, and cracks.

Fig. 2. Top view of the whole numerical model, cut through the clinch joint in the model and top detail.

3. Results 3.1. Experiment

The output of the tensile tests are force-displacement diagrams for individual specimens. The results from the tests on all types of specimens are shown graphically in Fig. 3. The resulting failure mode was similar in all cases (see Fig. 4). The joint fails at the neck, which is the weakest point of the clinch connection under the shear loading considered. Failure of the connection occurs by a combination of shear and partial bending stresses from eccentricity. The maximum forces ( F ult ) achieved during testing and the corresponding deformations ( u ult ) are given in Table 1 and the average force F el , which is the limiting force up to which the behaviour of the connection is evaluated as elastic, is also given. Specimen S1 was incorrectly seated during the test and the results must therefore be excluded from the file.

Table 1. Limit values read from the force-displacement diagram from the experiments. Mark F ult u ult

F el

S1 S2 S3 S4 S5 S6

9.81 kN 9.62 kN 9.61 kN 9.64 kN 9.51 kN 9.52 kN

1.09 mm 1.63 mm 1.94 mm 1.89 mm 1.74 mm 1.73 mm

8.31 kN 8.39 kN 8.81 kN 8.24 kN 8.26 kN 8.98 kN