Effects of liner properties on the stress and strain along liner/propellant interface in solid rocket motor

The aim of this study is to perform viscoelastic structural analyses to determine the effects of liner properties on the stress and strain along the liner/propellant interface in a solid propellant rocket motor. A simplified axisymmetric model composed of propellant, liner, insulation, and case was established, and nonlinear viscoelastic analyses were implemented in the finite element package ANSYS. The responses of the model under the cooling load and the ignition pressurization load were calculated. The results show that under the cooling load, the increasing of the thermal expansion coefficient (CTE) and equilibrium modulus of liner leads to the increasing of the stress along the liner/propellant interface. Under the ignition pressurization load, the stresses along the liner/propellant interface increase with the increasing of the initial modulus, and decrease with the increasing of Poisson's ratio of liner. In order to reduce the interface stress and improve the serve life of solid rocket motor, a liner with low modulus and CTE, and high Poisson's ratio should be applied between the insulation and propellant from the viewpoint of interface stress.