Constitutive Modeling and Finite Element Analysis of Fatigue - Damage in MetalMatrix Composites

摘要

A micromechanical consistent and systematic theory is developed for the analysisof damage mechanisms in metal matrix composites. A coupled incremental damage and plasticity theory of metal matrix composites is introduced here. This allows damage to be path dependent either on the stress history or the thermodynamic force conjugate to damage. This is achieved through the use of incremental damage tensors. The model involves both overall and local approaches to characterize damage in these material due to cyclic and monotonic loads. Expressions are derived here for the elasto-plastic stress and strain concentration tensors for fibrous metal matrix composite materials in the damaged configurations. A finite element analysis is used for quantifying each type of damage and predicting the failure loads of dog-bone shaped specimen and center-cracked laminate metal matrix composite plates. The development of damage zones and the stress-strain response are shown for two types of laminated layups.