A new theoretical model of the quasistatic single-fiber pullout problem: The energy-based criterion with unloading process

Abstract A theoretical analysis for the single-fiber pullout with unload process is presented based on the energy-based debonding criterion and the modified analysis of stress transfer between fiber and matrix(Qing [1]). The relationship between the applied stress and the interfacial relative displacement is expressed as a function of the radial residual thermal stress, fiber pullout rate and volume content as well as the length of reverse frictional sliding. The influence of fiber pullout rate on interfacial frictional coefficient is also taken into consideration. The calculation results show that the applied stress result in further debonding increases with the increase of the radial residual thermal stress and the fiber volume content and the decrease of the fiber pull-out rate. There is a drop for the applied stress when the interface debonding close to the model length and the drops of short models are larger than those of long models. Under different conditions, the model length almost has no influence on the debonding and reverse sliding in unloading processes at the initial debonding region.