Continuum damage approach for fatigue life prediction of viscoplastic solder joints
Résumé
The accurate and effective prediction of the failure for an inelastic structure, such as a solder joint in an electronic chip packaging, remains a current issue. Subjected to sub-critical cyclic loading, the solder can undergo fatigue cracks, leading to the failure of the whole system after a certain number of power cycles. In this paper, a model for describing the viscoplastic behavior of the solder material under power cycling is implemented in the finite element code Abaqus and a continuum damage procedure is used for lifetime prediction. Damage initiation criterion and damage evolution law, based both on the inelastic strain energy per stabilized cycle as proposed by Darveaux, are used in conjunction with the direct cyclic procedure available in Abaqus. This latter technique allows reducing the considerable computation time needed to obtain the stabilized states during the repetitive loading cycles.