Finite element analyses for evaluating fatigue strength of solder joints in electronic packages should employ a constitutive model which can describe cyclic deformations precisely. Therefore, the model should be constructed based on detailed information about the inelastic strain generated under the cyclic loading. We previously investigated both the plastic and creep strains of Sn-Ag-Cu (SAC) lead-free solder under cyclic loading experimentally by conducting cyclic loading tests using stepped ramp waves. In this study, we construct an elastic-plastic-creep constitutive model based on the experimental results, such as the stress-plastic strain relations, and the stress-creep strain relations obtained by the above-mentioned tests. The model considers the characteristics of the plastic and creep deformations in cyclic loading where loading direction changes. Simulations of cyclic loading of the SAC solder under several loading conditions are conducted using the proposed model and the results are compared with experiments. © 2011 Published by Elsevier Ltd.
Ohguchi, K. I., & Sasaki, K. (2011). Constitutive modeling for SAC lead-free solder based on cyclic loading tests using stepped ramp waves. In Procedia Engineering (Vol. 10, pp. 1139–1144). Elsevier Ltd. https://doi.org/10.1016/j.proeng.2011.04.189