Widely used in automotive and aerospace industry, clinched joints are subject to failure due to neck fracture and disjoining if exposed to high static loads. For cyclic loading cases, the formation of eyebrow cracks can be observed. The main objective of ongoing research is the application of the Local Strain Approach to clinched joints joining extruded aluminum wrought alloy sheets, thus being able to predict crack initiation location and fatigue life. Complex geometrical features of a clinched joint and lacking of nondestructive methods to track local stresses and strains require a combined approach utilizing numerical and experimental techniques. Material characterization for an aluminum wrought alloy EN AW 6060T66 is accomplished by common uniaxial tension tests to determine flow curves and cyclic properties by strain controlled constant amplitude tests, respectively.

Commercial finite element software LS-Dyna® is used to perform the process simulation in 2D, followed by mapping to 3D with constant amplitude loading to investigate local stresses and strains within the contact region. The Local Strain Approach with damage parameter PSWT is applied to estimate the fatigue lives of the clinched joint variants. Fatigue life estimations obtained from simulation results are compared to those from experiments.