The Analysis And Numeration Of Solid Rocket Propellant's Finite Element Theory

This paper did some research on numerical simulation about the structure of solid rocket propellant, based on the mechanical problem during the designing process and stockpile process of solid rocket propellant . Solid propellant is near-incompressible because of its high poisson ratio. The high poisson ratio will make the stiffness matrix singularity, So it's difficult to analyze the structure with common finite element method for its low accuracy and efficiency. In this paper, the viscoelasticity constitutive equation fitful for near-incompressible material is used, combining with the virtual work equation which is derived from the theory of continuous medium and isoparametric finite element method , the finite element model is set up, based on integral constitutive. At the same time, the element visco88 and visco89 are used to validate it , accompanying with FEM software ANSYS, VISCO88 is defined by eight nodes having two degrees of freedom at each node: translations in the nodal x and y directions. The element may be used as a plane strain or as an axisymmetric element. VISCO89 is defined by 20 nodes having three degrees of freedom at each node: translations in the nodal x, y, and z directions. These elements have thermorheologically simple (TRS) viscoelastic and stress stiffening capabilities. Examples indicates precision, even though v is closed to 0.5. Some useful results are gained , for example , the influence depending on the thermal expansion coefficient , possion's ratios and different boundary conditions, it's helpful to analysis solid rocket propellant.