Numerical analysis of fracture mechanisms and failure modes in bi-layered structural components

The problem of crack propagation in bi-layered structural components is addressed. Due to the presence of the bi-material interface and depending on the loading direction, a competition between different crack trajectories (failure modes) can take place. The quantification of the dominant failure mode and of the prevailing fracture mechanism is very often a challenging task, although it is crucial for design purposes. In this contribution, starting from the experimental observation of failure modes in a variety of engineering applications involving bi-layered structural components, an interpretation is proposed in the framework of the finite elements discretization and linear elastic fracture mechanics. The effect of thermo-elastic and residual stresses on the stability of crack propagation is carefully examined. Numerical results confirm the qualitative experimental observations of failure modes in bi-layered structural elements used for rock drilling applications.