Relative Damage Stress: Dominant Mechanical Factor for the Failure of Soldered Joints under Temperature Cycling

By temperature normalization of the concept of equivalent damage stress proposed by Lemaitre, a new concept of relative damage stress has been put forward as the dominant mechanical factor for the failure of soldered joints under temperature cycling. Finite element numerical simulation results showed that the highest value of relative damage stress occurred at the high temperature hold time during temperature cycling history.