Mechanical response of HTPB propellant grain under ultra-high overload

In this study, the mechanical response of HTPB propellant grain under ultra-high loads is investigated. The low, intermediate and high strain rate of uniaxial compression tastings (1.7×10-4∼3×103s-1) of the hydroxyl terminated polybutadiene (HTPB) propellant at room temperature were carried out by using the universal testing machine and the split Hopkinson pressure bar (SHPB) system, respectively. The uniaxial compression tests of the cellular rubber, the EPDM rubber and felted wool were carried out. A linear viscoelastic constitutive model of the HTPB propellant was developed by using the test data. The mechanical property of the cellular rubber, the EPDM rubber and the felted wool were studied by the test data. The dynamic mechanical response of the propellant grain under high overloads was simulated with the developed constitutive model by using the finite element method. The deformation of the grain under high overload was studied. The result shows when the overload value is maximum, the stress value of the grain is maximum. The location where the stress value of the grain is maximum is the center of the inner hole of the cushion. The maximum stress value is 20.17MPa.