Nonlinear analysis of 3-D solid rocket motor grain

Nonlinear analysis is a difficult point in structure analysis of grain. In order to study its effect on structure analysis, based on incompressible viscoelastic constitutive relationship and virtualwork equation of T.L, considering near-incompressibility and nonlinearity, a 3-dimensional viscoelastic geometry nonlinear finite element incremental relationship is derived. The 3-dimensional modeling and simulation are done under pressure and cooling. It is demonstrated by a comparison with linear method that nonlinearity has great effect on structure analysis of grain under large load and it is necessary to take into account nonlinearity in structure analysis of grain.