Analysis of crack extension paths and toughening in a two phase brittle particulate composite by the boundary element method

摘要

Crack extension in a two-phase compositeconsisting of a brittle matrix and cylindrical particles is simulatedusing a linear elastic boundary element program. Three crack extension paths:(i) deflection around the particle(ii) growing along the interface, and(iii) penetrating the particle are addressed.These depend on the elastic constant mismatch of the matrix andthe particle. Toughening is considered through the ratio of thestress intensity factors. Cracks will readily grow along a weakmatrix/particle interface, while a strong/stiff particle may forcethe crack to deflect around it, if the interface is strong. Inversely acrack easily penetrates a compliant particle. For the combinationof a strong particle and a moderate strength interface, hightoughening can be obtained when the crack tip is arrested. Astrategy for the update of element configuration when the crackintersects the interface is also presented, which lays thefoundation for analyzing the toughening promoted by ductileparticles using the boundary element method based on elastoplastic mechanics.