The role of stress state and stress triaxiality in lifetime prediction of solder joints in different packages utilized in automotive electronics

摘要

This work presents an overview on the role of the stress state and stress Triaxiality Factor (TF, see Eq. (1)) in lifetime prediction of solder connections. According to various literature sources, the TF is one of the most important factors influencing initiation of ductile fracture (Bao and Wierzbicki, 2004; Davis and Connelly, 1959). It is widely reported that lifetime of the ductile materials decreases under hydrostatic tension when combined with high TF-values. Recent investigations report that the compressive hydrostatic stress state combined with a high shearing load and low ( or even zero) TF-values also contributes to failure (Bao and Wierzbicki, 2005; Kweon, 2002; Nielsen and Tvergaard, 2011).