RIGID POLYURETHANE FOAM AS AN ENERGY ABSORBING CORE FOR COMPOSITE COMPONENTS MANUFACTURED BY RESIN TRANSFER MOLDING (RTM) .2. PREDICTION OFPROPERTIES AND VALIDATION OF CONSTITUTIVE MODELS

Foam constitutive models allow the effects of changes in parameters su ch as density to be predicted and can be used to generate input data f or non-linear finite element models. This paper considers three approa ches to the constitutive modelling of rigid polyurethane foams: (i) an empirically based shape function approach, (ii) an approach based on a consideration of the mechanics involved in the deformation of a unit cell and (iii) the construction of representative mechanical analogue models. Each approach considered in terms of its accuracy, general ap plicability and ease of use. It is found that the three methods vary p rimarily in their reliance on experimental data and that this directly influences their levels of accuracy. The choice of approach is theref ore largely dictated by the availability of appropriate test data.