Visco-Hyperelastic Constitutive Model for Modeling the Quasi-Static Behavior of Polyurethane Foam in Large Deformation

Flexible polyurethane foam is widely used in numerous applications such as seats and mattresses, due to its low stiffness and its ability to absorb deformation energy. The main objective of this article is to model the quasi-static mechanical behavior of three types of polyurethane foam in large deformation and to compare these three foams with three proposed models. The uniaxial compression/decompression tests at three different strain rates were performed. The test results show that the three foams present different plateau stresses, maximum stresses, and abilities to absorb energy. Moreover, polyurethane foam also presents a nonlinear hyperelastic behavior and a viscoelastic behavior in large deformation. Three visco-hyperelastic models which include a hyperelastic component and a memory component are proposed to model these behaviors. Model parameters were identified using the experimental data and a proper identification method. These models were validated on these three types of foam with the aim to present comparison results. The comparison results show that Ogden's viscoelastic model best agrees with the experimental results. (C) 2014 Society of Plastics Engineers