Structural Integrity Analysis Of Grain Considering Inhomogeneity Of Mechanical Properties Of Propellant Materials

The solid rocket motors are the main power device of missile weapons and space vehicles,and the structural integrity of grain determines the success or failure of the launch mission.At present,when carrying out the analysis of the structural integrity of the grain,the propellant mechanical properties were considered to be uniformly distributed.In fact,the propellant mechanical properties were non-uniform in the structure of grain.In this paper,focusing on the non-uniformity of propellant mechanical properties,the UMAT subroutine was used to establish a numerical simulation analysis method for the structural integrity of grain considering the non-uniformity of the mechanical properties of the propellant,and to explore the influence of the non-uniformity of the mechanical properties of the propellant on the structural integrity of grain The main results of the paper are as follows:(1)Based on the three-dimensional extension theory of linear viscoelastic constitutive model,a three-dimensional discrete method of nonlinear ZWT constitutive model with damage was proposed.The three-dimensional form of the constitutive model was applied to provide a basis for subsequent analysis and research by compiling UMAT subroutines;(2)Based on the influence of the curing strain generated by cooling process after curing on the mechanical properties of propellant materials,a method for analyzing the structural integrity of grain considering the effect of curing strain was proposed,and the effect of curing strain on the structural integrity of grain was analyzed;(3)Based on the changing law of the mechanical properties of propellant materials in the confining pressure environment,a method for analyzing the structural integrity of grain considering the confining pressure effect was proposed,and the influence of the confining pressure effect on the structural integrity of grain iwas analyzed;(4)Based on the asymmetry of mechanical properties of propellant materials,an analytical method for the structural integrity of grain considering the asymmetric effect of tension and compression was proposed,and influence of asymmetric effects of tension and compression on the structural integrity of grain was analyzed.This paper proposes an method for analyzing the structural integrity of grain considering the non-uniformity of the mechanical properties of the propellant and which can provide some theoretical and engineering support for the structural integrity and life of the solid rocket motor grian.