Constitutive modeling of polyurea properties

With the increasing use of polyurea in different applications, numerical modeling has also been the focus of concurrent research efforts. Mechanical behavior of the material including strain rate effects are important in the constitutive modeling of hyperelastic materials such as polyurea. The constitutive behavior of polyurea is discussed in this chapter using a case study. The development of a strain rate sensitive behavior of polyurea based on the well-known Mooney-Rivlin (MR) model is presented. A strain rate correction factor was introduced based on the strain energy density function. Derivation of the nine-parameter MR constitutive equations, including the rate correction factor is presented. The stress-strain behavior and internal energy of polyurea at different strain rates are predicted by the proposed model in close agreement with the experimental values. The proposed constitutive model can be implemented as a user-defined material in commercial finite element software such as LS-DYNA and ABAQUS.