A nonlinear viscoelastic constitutive model of solid propellant

A nonlinear viscoelastic constitutive model for solid propellant is propose d. The viscoelastic dewetting criteria is developed and the softening of th e solid propellant due to damage is treated by the modulus decrease. In the calculation of the modulus decrease, the modulus of void, which is created by dewetting, is modeled with non zero constant values. The values of adhe sion energy between the binder and AP particle are obtained by a modified 1 80 degrees peel test. The nonlinearities during cyclic loading are accounte d for by the functions of the octahedral shear strain measure. The model is evaluated with different loading conditions and the predicted values well matched the measured ones. The model provides a simple and convenient means to predict solid propellant behavior without requiring a complex micromech anical description. (C) 1999 Elsevier Science Ltd. All rights reserved.