Residual stress development due to cool down in a viscoplastic metal matrix composites

Abstract

The effect of different cool-down rates from processing temperature on the residual stress evolution in the representative volume element (RVE) of a periodic continuous fiber metal matrix composite monolayer is analyzed in the present study. A nonlinear incremental finite element program that accounts for thermoviscoplasticity in the matrix is utilized for the micromechanical analysis. The uncoupled heat conduction equation is solved for the temperature distribution in the RVE for given cooling rates. Comparisons between thermoelastic and thermoviscoplastic predictions of residual stresses at the interface between the fiber and the matrix demonstrate that viscoplasticity may be significant in predicting certain mechanisms such as interfacial and radial matrix cracking. Mechanical loadings are applied both at room temperature and operating temperature. The location and time at which interface debonding initiates is obtained. Average stress-strain curves are obtained for the cases of mechanical loading with or without residual stresses.