Complex fatigue of soldered joints - Comparison of fatigue models

The application of rainflow analysis to solder joint fatigue analysis is new. Rainflow analysis applies models developed from simple fatigue tests to predict complex fatigue life. In the work reported here, simple and complex fatigue testing was performed on single, eutectic tin-lead solder joints using a custom micromechanical tester. Simple, sinusoidal wave fatigue data were fitted to four models. From these models (two empirical models, a Coffin-Manson-based plasticity model, and a hysteresis energy model) fatigue life was predicted for complex wave conditions using rainflow analysis with linear damage accumulation. The correlation between the test data and complex fatigue model results was good, with correlation coefficients ranging from 0.956 to 0.977.