Micromechanical analyze of strain rate response on damage evolution in Sheet Moulding Compounds composites SMC-R

摘要: Analysing the damaged elastic behaviour of composite materials under dynamic loading requires an understanding of the damage mechanisms evolution in function of the strain rates. This comprehension relies upon the development of theoretical simulation approaches and experimental methodologies for strain rates up to 200 s-1.Our objective is to analyse experimentally, at microscopic and macroscopic scales, the influence of the strain rate on the behaviour and damage kinetics of the SMC-R26 (randomly oriented glass fibres reinforced polyester with 26% of fibre volume content) composite material subjected to a rapid traction. This experimental analysis will eventually feed in a micromechanical model of the behaviour at high strain rates (200≤ εq s-1). The micromechanical models based on the Mori-Tanaka model and coupled to probabilistic approaches have shown their effectiveness in the prediction of the composite material behaviour under quasi-static and cyclic stresses [1-3]. A multi-scale model is under development. In a first step, knowledge of the fibre-matrix interface is thus essential for the prediction of the mechanical composites behaviour. The micromechanical stress field will be calculated in order to predict the fibre-matrix interface failure with an appropriate statistical failure criterion. The dynamic tensile tests performed on the SMC-R26 composites enabled to clearly highlight the influence of the strain rate on the macroscopic response of material (figure 1).