Simulation of Fatigue Damage in Solder Joints using Cohesive Zones

Fatigue damage initiation and propagation in a solder bump, subjected to cyclic loading, is sim-ulated using a cohesive zone methodology. Damage is assumed to occur at interfaces modeled through cohesive zones in the material, while the bulk material deforms elastoplastically. The state of damage at an interface is incorporated into the traction-displacement law of the cohesive zone by a damage variable. The gradual degradation of the interfaces and the corresponding damage accumulation throughout the cycling process is accounted for by an interfacial damage evolution law, which captures the main failure characteristics.