Structural integrity analysis for the canular solid propellant grains subjected to temperature loading

For test-firing failure evaluation of the canular solid propellant grains under low temperature surrounding, the thermoviscoelastic large deformation incremental constitutive equation was derived based on Updated Lagrangian method. In order to investigate the transient temperature field and the distribution of thermal stress and strain, a step-by-step finite element model accompanied by concepts of time-temperature shift principle and thermorheologically simple material assumption was used. In addition, the dangerous location was obtained from the simulation. Twelve different thermal expansion coefficients and fourteen thickness coefficients were assumed to evaluate the effects on the structural integrity. The results show that thermal expansion coefficient has a linear relation to the maximum equivalent stress and strain response, whereas thickness coefficient has an exponential relation to them, which show that thickness coefficient plays an important role in structural integrity of solid propellant grains.