Three-dimensional finite element analysis of the mechanical behavior of cross-ply reinforced aluminum

Abstract

The current study investigates numerically the mechanical behavior of an aluminum alloy reinforced bidirectionally with SiC fibers by using the finite element method. First a three-dimensional unit cell is derived from a geometrical idealization of the fiber arrangement. Special emphasis is placed on the inelastic material behavior of the metallic matrix because of its strong influence on the composite behavior. Therefore a comprehensive coupled plasticity-damage theory is proposed, which permits an improved material description by using the transition flow potential (TFP). Cooling processes during manufacturing induce a pronounced inhomogeneous residual stress state in the composite resulting in local plastic matrix deformation. These stresses have a considerable influence on the mechanical behavior, so that different stress–strain responses under tension and compression can be observed. Under cyclical mechanical loading with a constant strain amplitude, simulations show a shift of the remaining strain (called ratchetting) and a narrowing of the hysteresis loop with increasing cycle number. Residual stresses induced during manufacture cause an asymmetric hysteresis with varying magnitude and temporal development of maximum and minimum averaged stresses.