Study on Rate-Dependent Characteristics of 'Dewetting' Point of Composite Solid Propellant

“Dewetting” can happen between solid particles and matrix of solid propellant during loading process. The strength and elongation at “dewetting” point are directly related to loads. The study based on the stress-strain response curve characteristics of a propellant under low temperature, different superimposed pressures and strain rates, the “dewetting” point of the propellant has shown obvious rate and superimposed pressure correlation, and the superimposed pressure load would inhibit “dewetting”, especially can influence the stress-strain curve with peak value of “dewetting” point at high strain rate. In order to obtain the rate-related characteristics of the “dewetting” point of the propellant, the mesoscale geometric particle inclusion model of the composite propellant is obtained based on the idea of molecular dynamics method, the mesoscale finite element model is created to calculate the “dewetting” damage of solid propellant under different strain rates. Finally, the damage mechanism of propellant “dewetting” under different strain rates is revealed, and the main reason of abruptly decrease of elongation of propellant at low temperature and high strain rate is explained by the influence rule of strain rate on “dewetting” point. It is found that the propellant failure depends on the interaction of the number of damage interfaces and the degree of interface damage in the process of damage evolution, which is a dynamic process.