In mechatronic devices, the fatigue of the solder joints is a mechanism leading to rupture and which is generated during the severe stresses encountered in operational environments. These thermal or mechanical stresses are variable over time (temperature variation, vibrations, and repeated shocks); the solder joints are thus subjected to fatigue. However, it is necessary to understand the damage of these solder joints under cyclic loading, through the determination of the stress and deformation levels.
Finite element methods are broadly used to this objective. To realize this modeling, it is necessary to choose an adequate geometric modeling, and to know sufficiently the mechanical materials behavior.
Many of the modeling techniques were used based on the global model of the studied mechatronic device, which requires a very high calculation time
In order to reduce the computational time, a submodel of the worst case solder joint is developed. This submodel is based on the geometry of the full model.
This submodeling technique allows us to model precisely the inelastic strain of the solder joints. It consists in describing the worst case solder joint with fine mesh elements and in taking into account material nonlinearities. The solder material is assumed to have a rate dependent plasticity.