Steady-state creep rate of a composite: Two-dimensional analysis

Abstract

A new method is proposed for calculating the steady-state creep rate of a composite, when the inclusion geometry and the matrix creep law are known. The method is demonstrated in a simple two-dimensional problem. During steady-state creep, an increment in plastic strain in the matrix causes a jump in displacement on the interface between the matrix and an individual elastic inclusion. The jump is counterbalanced by that due to diffusion and sliding on the interface. The rate of diffusion is determined by a normal force distributed on the interface and that of sliding by a tangential force. From these forces, the average stress in the inclusions is calculated; it is proportional to the steadystate creep rate. From the condition that an external stress is a volumetric average of the stress in the inclusions and that in the matrix, the constitutive equation of stationary creep of the composite is formulated.