Influence of matrix plasticity and residual thermal stress on interfacial debonding of a single fiber composite

Abstract

Fiber/matrix interfacial debonding in a single short-fiber reinforced polymer composite is investigated using finite elements and a cohesive zone model. The glass fiber is modeled as an isotropic, linear elastic material. The matrix is modeled as a linear elastic/elastoplastic material characterized by incremental isotropic hardening. A cohesive zone model governed by the traction-separation law describes the fiber/matrix interface. The simulated stress field of the single fiber debonded and perfectly bonded composites are compared. The results indicate that the interfacial shear stress decreases to zero on the debonded interface. It increases to its maximum value over a small processing zone and decreases exponentially to zero at the fiber midpoint. The debonding length growth in the plastic model is larger than that in the elastic model at small applied strain levels, but the trend is reversed as the applied strain level increases. The influence of factors such as residual thermal stress, interfacial strength, and fracture toughness on the debonding process of a single fiber composite are discussed.