Study on Constitutive Relation of PVC Foam Based on Microstructure Model

The mechanical properties of foam materials are closely related to the mechanical properties of the matrix material and the geometrical characteristics of the microstructure. In this paper, a novel method of constructing a microstructural model of transverse isotropic closed-cell foam is proposed and uniaxial tensile simulations of PVC foam are carried out based on this model. The simulation results of the established finite element model are in good agreement with the experimental results. The effect of the change in aspect ratio and relative density on the mechanical properties in compression of the isotropic microstructure into a transverse isotropic microstructure is then investigated through numerical simulations, and the prediction equations for the tensile modulus and tensile yield strength of the closed-cell PVC foam are established. Finally, a relatively simple uniaxial tensile constitutive equation is proposed, so that the tensile stress–strain curve can be determined by as few parameters as possible. The parameters in the equation are related to the relative density and aspect ratio, and the phenomenological tensile constitutive equation is established.