ABSTRACT
Parameters for constitutive models of rubber-like materials cannot be taken from standard tests, but have to be determined by special tests for simple stress states. This chapter presents a constitutive model, which consists of parallel models for the hyperelastic, viscoelastic and elastoplastic response of the material, for elastomeric material and includes a damage parameter describing the Mullins effect. It compares two ways: a separate determination of hyperelastic, viscoelastic, elasto-plastic and damage parts of the constitutive model and a determination of the parameters by fitting data from the original tests, using a reduced number of tests. Additionally, an evolutionary algorithm is used for parameter identification; these results are compared with those of the least square fit procedure. The base of the description of viscoelastic behavior of elastomers is the concept of internal variables. The elastoplastic part of the model is described by finite elastoplasticity.
