In situ X-ray tomography study on internal damage evolution of solid propellant for carrier rockets

Abstract

Nitrate Ester Plasticized Polyether (NEPE) propellant has been widely used for carrier rockets. However, the propellant is usually subjected to complex loads, changing the microstructures, which eventually affects its structural integrity. To elucidate the damage mechanism of the propellant, an in situ tensile testing rig with a maximum strain rate of 0.1 s−1 was developed with high-resolution synchrotron X-ray tomography. The internal microstructure and the resultant damage evolution have been characterized quantitatively. The mechanical behaviour of sampled propellant was extracted from the dynamic mechanical analysis. In addition, numerical simulation in terms of the spatial geometry of filler particles was performed in the framework of the micromechanical approach. To visualize the debonding process, a cohesive-zone model was employed to trace the debonding at the filler/matrix interface and then the damage evolution was characterized according to the cohesive behaviour. The results can assist in correlating the cohesive behaviour due to local heterogeneity with the macroscopic mechanical response for the NEPE propellant.