Computational analysis of polyurethane foam expansion process in fiber reinforced sandwich structures

In this paper, we present numerical simulations of expansion process of polyurethane foam in fiber reinforced sandwich structures. The material and mechanical properties of polyurethane (PUR) foam structures can be enhanced by integration of fiber reinforcement in the mold prior to the injection of the reactant (polyol and isocyanate) polymer blend. In addition, the mathematical modelling and simulation of free rise expansion process of PUR foams in simple geometries suggests that the final morphology of the expanded foam is highly influenced by the interplay between the chemorheological viscosity, temperature, gas volume fraction and degree of polymerization of the foaming mixture. However, in modelling the foam expansion process through warp-knitted spacer fabrics, one must account for the additional effects originating from the porosity and/or permeability of such layers. This additional effect generally introduces another level of difficulty in the mathematical description of such physical setup. The emerging system of nonlinear partial differential equations governing the flow is solved in appropriate geometry and boundary conditions using CoRheoS; an in-house simulation platform based on the finite volume method. With graphical illustrations , we present the flow of the expanding foam in the medium and determine the porosity of the fibrous structure. The results from this ongoing investigation is anticipated to assist foam process and structural engineers in understanding some intricacies that occurs in the porous media flow of expanding polyurethane foams mixtures.