Uncertain structural analysis of solid propellant grain and comparison of the methods

Concerning the influence of uncertainty in composite solid propellant's mechanical properties on structural analysis of solid rocket motor (SRM) grain, the parameterized finite element model of SRM grain under temperature and pressure loading is constructed through ANSYS parametric design language (APDL). On that basis, the influence of random distribution of composite solid propellant's thermal expansion coefficient and initial Poisson's ratio on finite element structural analysis of SRM grain is studied with Monte-Carlo method and response surface method. Results of the two different methods are compared. The results show that small changes in composite solid propellant's thermal expansion coefficient and initial Poisson's ratio cause relatively great influence on the results of structural analysis and the structural responses of the propellant grain are more sensitive to initial Poisson's ratio. So, uncertainty in composite solid propellant's mechanical properties should be considered during finite element structural analysis of SRM grain. It is indicated by the comparison of this two kinds of methods that response surface method can give approximately the same results as those from Monte-Carlo method and is greatly more efficient than Monte-Carlo method.