Constitutive Modelling of High - Elongation Solid Propellants

A phenomenological approach is used to represent the nonlinear viscoelastic behavior of solid propellants. A three dimensional nite strain viscoelastic model, modi ed by a strain softening function that accounts for damage e ects, is considered in the research. Some of the signi cant aspects of high-elongation propellants are incorporated into the constitutive model. The resulting stress-strain relation is applied to a particular high-elongation propellant by means of the related material characterization. The response predicted by the model is compared with the experimental data for di erent loading conditions. The model predicts the propellant behavior quite well at uniaxial strain magnitudes up to 50%. Numerical analysis of very general geometries and loadings are possible, since a fully general model is calibrated. Nomenclature A = A 1=3tr(A)I C = right Cauchy-Green deformation tensor