Peridynamics for Microstructural Damage Modeling of 3D Carbon/Carbon (C/C) Composite Materials

This study presents a peridynamic model to investigate damage initiation in complex 3D C/C microstructures for optimal design and fabrication. The peridynamic theory unifies the mechanics of continuous and discontinuous media. It is a continuum approach without spatial derivatives, thus without mathematical singularities. It restores nonlocal interactions and introduces an internal length parameter (horizon of a point) which links different length scales. Because of these features, it enables autonomous multiple damage initiation sites and their complex interactions at unspecified locations along unguided paths. The numerical results concern damage initiation and growth in a complex 3D C/C microstructure. A repeating representative volume element (RVE) composed of yarns and surrounding matrix is constructed according to the periodic architecture of the 3D woven C/C composites. The analysis is conducted through a mixed implicit-explicit algorithm with GPU parallel computing. The strength properties of the constituents are used to determine the critical stretch for damage initiation and growth in the microstructure. The isolated initial micro cracks start merging as the load increases. Subsequently, the crack front reaches to the surface of a nearby fiber. However, the micro-crack cannot pass through that fiber directly. Instead, it deflects along the fiber direction and starts climbing up around the fiber lateral surface.