Jochen Hebel

Numerical Analysis of Brittle Crack Initiation at Stress Concentrations in Composites

As potential locations for failure initiation, stress concentrations require sophisticated analysis models. In composites, not only geometrical discontinuities may cause high local stresses, but also material discontinuities or even a combination of both. A universally applicable hybrid approach utilizing finite fracture mechanics is employed in this study to model crack initiation at stress concentrations. It overcomes deficiencies of classical criteria. The model is implemented in a versatile finite element procedure. Examples demonstrate the capability of the model to cover relevant effects for simple configurations as well as for glass-ceramic sealing joints in solid oxide fuel cells subject to thermomechanical loading.