Assessment of the contact parameter influence on fatigue-induced wear in clinched joints

The growing demand for lightweight body-in-white concepts, driven by stringent emission regulations, has intensified the application of mechanical joining technologies in automotive engineering. Clinching has proven to be an efficient method for joining similar and dissimilar sheet materials. However, under cyclic loading, complex wear mechanisms such as abrasion and fretting can occur, significantly affecting fatigue performance and service life. To investigate these mechanisms under realistic conditions, a novel tribo-torsion test rig was developed and validated. This setup enables the controlled reproduction of service-relevant interface pressures and relative displacements in clinched joints. A Design of Experiments (DoE) approach was applied, with test parameters derived from cyclic shear–tensile simulations at a load ratio of R = 0.1. The developed axial com- pression–torsion fretting test configuration allows high interface pressures combined with defined, cyclic dis- placements, capturing the transition from mild oxidative to adhesion-dominated, severe wear. These transitions are characterised by black debris formation, cold welding, and an increase in surface roughness at elevated load levels. To confirm transferability, the experimental results were benchmarked against real clinched joints under cyclic shear–tensile loading, showing strong agreement within interface pressures of 150–200 MPa and relative displacements of 130–260 μm. Furthermore, the observed roughness evolution, oxide formation, and fretting- specific debris confirmed the validity of the approach. The presented methodology thus provides a validated experimental framework for analysing tribological degradation mechanisms in clinched joints, and establishes a foundation for predictive models aimed at improving fatigue life assessment.