Peridynamic modelling of crack initiation and propagation in thermo-mechanically loaded electronic devices

Surface mounted electronic devices (SMD) are subjected to complex thermo-mechanical loads during manufacturing as well as during their service life. Even during manufacturing, voids and cracks can nucleate in soldered joints and also in components such as capacitors, made of brittle materials. An initial damage can have a detrimental effect on the lifetime of the product. Modelling of crack initiation and propagation is difficult in classical finite element analysis (FEM), due to the singularity of the mathematical functions in the differential analysis. Extended FEM (X-FEM) and meshless methods were developed to overcome these problems, nevertheless thermo-mechanical coupling of cracks and crack branching is still open for further research. Peridynamic Continuum Modelling (PCM) is dedicated to solve the crack initiation, propagation and fracture by integral equations. In original bond-based peridynamics, tearable springs are defined between all the couples of material points of the continuum, while in a more advanced formulation as a state-based modelling, a force vector is defined as well. In this work, the state based peridynamic model of the coupled thermo-mechanical problem was developed, and applied to detect deformations due to thermal loads of board models, and initiation and propagation of cracks during cooling, in relation with modeling wave soldering technologies of components to a printed circuit board.