Within the frame of a research project at PSA, crash modelling has been set up for structural parts of a body-in-white made of E glass/vinylester composite material and Polyurethane crushable foam.
The first part of this paper presents the methodology applied for the characterisation of composite materials under strain rates between 10-2 s-1 and 100 s-1. A classical Johnson-Cook mechanical law has been proved efficient to model the composite material behaviour and a elastic-plastic mechanical law has been modified for PU foam.
In the second part, comparisons between experiments and calculations are made for different cases of increasing complexity (from specimen to vehicle front-end). A good correlation for the crushing load as well as for the absorbed energy or the final displacement, is obtained for E glass/vinylester components and sandwich structures with E glass/vinylester and Polyurethane foam.
However, the scattered mechanical properties of E glass mat/vinylester materials and the drawbacks inherent to the commercial software packages available today for crash modelling (imperfect mechanical laws, strong dependency on numerical parameters) as well as the difficulties in modelling the joining of composite parts, preclude a fully reliable prediction of the crash behaviour of composite structures or components.