| A new damage model based on percolation theory is proposed. The damage-based failure criterion is formation of a macrocrack. The model is applied to 63Sn-37Pb solder, since the experimental data shows that evolution of damage during a substantial portion of its fatigue life is governed by microcrack nucleation with the rate of nucleation being almost constant. The observed microcracks originate at interfaces between phases and between grams and remain microcracks because of microstructural obstacles to growth. Despite the natural scatter the model predictions of the salient trends in the experimental data are quite good. |
