Enhancements on a micromechanical constitutive model of solid propellant

• A micromechanical constitutive model of solid propellant is enhanced.
• Strain rate and temperature effects are implemented into the shear modulus of binder matrix.
• Cyclic loading behaviors are treated with proposed unloading and reloading curves.

A constitutive model of solid propellant based on the micromechanical approach is presented. Proposed model includes the effects of temperature and strain rate dependency, and severe nonlinearities under cyclic loading. Damage is represented by the reduced elastic moduli which is the function of the void volume fraction. Dependency of the material properties on temperature and strain rate is incorporated in the shear modulus of the binder matrix. Using the test data from the uniaxial tests, it is expressed as a function of temperature and strain rate. Using the function, homogenized elastic tensor represents the effects of temperature and strain rate. The cyclic loading behaviors are controlled by introducing artificial strain rate and modified stress based on the unloading and reloading curves. Proposed constitutive model is implemented into the user subroutine of ABAQUS. Finally, accuracy of the constitutive model is verified under various loading conditions.