Simulation Study on Influences of Damage-Induced Mechanical Interactions, Residual Stresses and Interfacial Frictional Shear Stress on Interfacial Debonding in Multifilamentary Composites

Abstract

The overall interfacial debonding in unidirectional multifilamentary composites is affected by many factors such as damage(broken components (fiber and matrix) and interfacial debonding)-induced mechanical interactions, residual stress and frictional shear stress at debonded interface. In the present work, the influences of such factors on debonding behavior were studied by applying the simulation method, in which the modified shear lag analysis was combined with the energy release rate criterion for debonding, to the various spatial distributions of cut-ends of components in a two-dimensional model composite. Main results are summarized as follows. (i) The progress of debonding is dependent on number, species and geometrical location of cut components. (ii) The overall debonding progresses more rapidly with increasing number of cut components due to the enhanced mechanical interactions. (iii) The debonding progresses intermittently, resulting in serrated stress-strain curves. (iv) When tensile and compressive residual stresses exist in matrix and fiber, respectively, along the fiber axis, they act to enhance and retard the debonding when the matrix and fiber are cut, respectively. (v) The frictional shear stresses at debonded interface act to retard the debonding and to raise the load carrying capacity of the composite in which debonding is saturated.