DCB testing of thermoplastic composites: A non-linear micro-macro numerical analysis

A micro-macro finite-element analysis is presented of the development of plastic deformation in DCB rests on unidirectional thermoplastic-matrix composites. The objective is to understand the mechanisms responsible for the experimentally observed decrease in toughness relative to the pure matrix. We compute the complex stress and strain fields near the crack tip. On that basis, estimates of fracture toughness and plastic energy are predicted numerically. Results are discussed for a glass-fiber-reinforced amorphous poly(arylamide) matrix. We find that the plastic zone is not restricted in size by the reinforcement. Numerical predictions for fracture toughness and plastic energy density show a decrease relative to those of the pure matrix, as observed experimentally. (C) 1997 Elsevier Science Limited.