Micro numerical simulation of creep damage and failure of short fiber reinforced metal matrix composites (MMCs)

The mechanisms of the creep damage and the failure of the short fiber reinforced metal matrix composites (MMCs) have been investigated. The unit cell models are applied for the plane randomly-distributed-fiber MMCs by means of the finite element method (FEM) of ABAQUS. The creep damage and failure of the matrix is simulated by the K-R damage model, which has been implemented as the user subroutine CREEP of ABAQUS. The breakage of the fibers is simulated by the stress criterion, it means that the breakage will occur when the axial stress of the fibers reaches the critical value. This stress criterion has also been implemented into the ABAQUS. The influence of the fiber breakage on the stress distribution has been obtained. The FEM results show that the creep damage is localized near the corners of the fibers and the fractured surfaces of the fibers after the breakages of the fibers occur. And the fiber breakage has very limited influence on the creep damage of the matrix, but it reduces a high stress concentration in the matrix near the fractured surface. This high stress concentration will help the crack enlargement in the matrix by the stress criterions.