Experimental Study on The Parameters of the Viscoelastic-Plastic Constitutive Model of a Certain Solid Propellant

The mechanical behavior of a certain solid propellant is not only obviously related to time, temperature, and load loading history, but also is a viscoelastic plastic material under certain conditions. Based on the principle of creep deformation superposition, the strain of the solid propellant material is decomposed into a viscoelastic part and a viscoplastic part, and the nonlinearity of the viscoelastic-plastic constitutive model is manifested by the introduction of nonlinear coefficients. According to the characteristics of the viscoelastic-plastic model of the solid propellant material, the relevant tests were designed. The viscoplastic parameters were determined by using the creep recovery test data of multiple cycles until the failure of the propellant material sample. The viscoelastic parameters of the solid propellant material were obtained by using the data from recovery tests performed under different stress conditions.