Influence of the Residual Stresses on the Mechanical Behavior of Advanced Composite Parts

Abstract

The cooling condition in the forming process (resin transfer molding (RTM), structural resin injection molding (SRIM), laying-up) plays an important part in residual stress distribution in the advanced composite pieces. The residual stresses, which are induced during the cool-down process following high temperature consolidation, result from the coefficient of thermal expansion (CTE) mismatch between plies. This paper describes the development of a finite element method to simulate the prediction of residual stresses and strains fields induced by cool-down process. In this research we used incremental hole drilling method combined with acoustic emission to understand the chronology of damage events, the development of damage modes (matrix cracks, laminate delamination and fibers fractures). The laminate plates [0₂/90₂]_s, was polymerized with three different cooling conditions (fast, normal and slow). Specimens cut from these plates were tested to measure their tensile strength and to investigate the influence of residual stresses on the mechanical behavior of laminate structures.