New Techniques to Test Fatigue Properties of Coined Sheet Specimens. Part 3.Fatigue Testing and Analysis of a Component Like Coining in Sheet Steel Materials

摘要

Coinings are normally introduced in sheet components in order to increase theoverall stiffness of the panel. In fatigue loaded components the coining may serve as a potential site for crack initiation. The reason is that bending stresses in the sheet are transferred up into the coining producing a stress concentration. Also, due to the forming of coining sheet thickness is often reduced, which increases the stresses locally. The present work is directed to the work of simulating the fatigue behavior of coinings in steel sheets. A specimen design was developed which comprises the main features of coinings in real life automotive components. Simultaneously to the experimental work, numerical work was done in order to predict the fatigue life of the coined geometry. The numerical models utilized finite element techniques with a non-linear kinematic hardening model to describe the behavior of the specimen both during forming and during fatigue loading. The local strain approach was adopted to estimate the fatigue life.