Evaluation of Dynamic Compression Modulus of Flexible Polyurethane Foams by Dynamic Viscoelastic Measurements

Abstract

In this study, the dynamic modulus of some flexible polyurethane foams was determined by the dynamic viscoelastic measurements in compression mode. As the result, the dynamic modulus is found to evaluate compression characteristics of foam as well as other dynamic properties. Especially, the dependence of the dynamic modulus on the initial shrinkage is considered to be important for the understanding of cushion properties.
The Young's modulus of the flexible polyurethane foams was evaluated by the finite element method (FEM) using a personal computer. The calculated value following from the two-dimensional model with six-angular pores analyzed by FEM using the plane stress element gave improved agreement with the calculated results of Thomas-Gent and Lederman. Furthermore, the calculation based on the two-dimensional model analyzed by FEM using beam element was found to be in a reasonable agreement with the experimental data for the dynamic modulus of elasticity.