Cyclic compression test on the bolt head. (Left) Evolution of force F(t) with respect to time t during the first 25 triangular loading cycles, where the force does not come back exactly at 0 N but at 10 N in order to avoid rupture and contact problems that could be not detected by the load cell. (Right) Evolution of force F(t) with respect to displacement u(t), showing a preliminary phase (similar to a static compression test) during the first cycle, followed by more regular cycles (the model focuses on the regular cycles).