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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suitability for automated production. TWCF structures are therefore a key area of research (Bernuzzi and Maxenti, 2015; Lei et al., 2019). Much of the existing research focuses on understanding how individual factors influence the final shape of the clinch joint. This is because clinching is highly repeatable in manufacturing, making it ideal for automation. Other studies are investigating different types of damage and their impact on failure modes. This particular research investigates how clinch joints behave under typical building loads, assuming a reliable pre-manufacturing process that ensures flawless joints and predictable failure patterns (Flodr et al., 2017). Verification of experiments and numerical models is also a major problem (Atia and Jain, 2018; Hamel et al., 2000; Varis and Lepistö, 2003). The paper builds on a pilot study previously published, where the basic concept of joint testing, evaluation and numerical modelling of such a joint was introduced (Flodr et al., 2020). In the original paper, a connection with a plate thickness of 2.67 mm was presented, while here the results of tensile testing of the material, clinch connection and numerical modeling of the 3.45 mm thick material are presented. 2. Experimental and numerical program 2.1. Material and test setup Physical experiments of tensile tests of clinch joints loaded by shear have been carried out for several thicknesses, in this paper the results are presented for a thickness of 3.45 mm. A clinch tool with punch designation P8184 and die SR603 was used to join the plates. The static experiment scheme corresponds to the shear loading of the joint, since it is two separate sheets clamped outside the specimen center of gravity. In Fig. 1. (a), the fixed test specimen in the electromechanical press can be seen. The test specimens were made of S390GD material. According to the data sheet, the declared minimum yield strength is 390 MPa. Prior to the experiment, tear tests were performed on the material for the purpose of calibrating the numerical model. The physical experiment was designed as a tensile test of the specimen and was terminated by failure. In the laboratory test, the dependence of the imposed force on the deformation was monitored and 5 tests were performed. Fig. 1. (b) shows photographs of one specimen before and one after the test, as well as a detail of the clinch joint.

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Fig. 1. (a) Test specimen fixed in electromechanical machine; (b) specimens before and after testing; detail of clinched specimen.