In order to study the influence of temperature impact load on the structure integrity of a modified double-base propellant grain

mechanical relaxation tests of the modified double-base propellant at different temperatures were carried out based on the basic theory of thermo-structure coupling. The sixth order Prony series of relaxation modulus at different temperatures and the time-temperature equivalent W.L.F (Williams-Landel-Ferry) equation with 293.15 K as the reference temperature were obtained. Ansys finite element method software was used to analyze the structure integrity of the grain under the temperature impact condition from 333.15 K to 218.15 K. The results showed that the temperature and strain of the grain changed sharply in the early stage of temperature impact

and basically reached balance at 12 000 s. Two corners of the grain front face were damaged in the early stage of temperature impact. In order to verify the simulation results

from 333.15 K to 218.15 K temperature impact test was carried out. The results showed that: in the process of temperature impact

the propellant column cracks appeared along the axial and radial directions

and the crack initiation points were at the front two corners of the propellant grain. The temperature impact test results verified the accuracy of the simulation calculation

which showed that the calculation process can be used to analyze the structural integrity of grain.