鉛フリーはんだに適用される汎用FEAソフトの構成モデルが累積非弾性ひずみ挙動に及ぼす影響

摘要

It is important that evaluations of thermal fatigue life of lead-free solder joints under cyclic temperature changes are performed more than before exactly. We have to conduct FE analysis using a constitutive model in order to estimate the fatigue life of solder joints. There, classical isotropic hardening elastic-plastic-creep model, classical kinematic hardening elastic-plastic-creep model and Anand model are often used because these models are implemented into commercial FEA soft. In this study, as such mechanical properties of the lead-free solder joints, stress-strain curves, stress-strain hystereses and stress-relaxation curves with these temperature dependencies and these rate dependencies were regarded. And, how accuracy simulation results by these model accord with these experimental test data were investigated. Next, using these models, FE structural analysis of solder joints under cyclic temperature change on actual equipment were conducted and the accumulated inelastic strain behavior were gotten. Finally, the characteristics of each constitutive model were connected with these behavior.