Experimental study of propellant/liner interface fracture characteristics

The propellant/liner interface debonding is one of the main failure modes affecting the structural integrity of solid rocket motors. In order to study the mechanical properties of the propellant/liner interface, the Double-Cantilever Beam (DCB) specimen of the propellant/liner interface was improved. Based on the propellant/liner interface DCB specimens, tensile tests at different temperatures and loading rates were carried out. Based on the digital image correlation(DIC) method, the strain field of the whole DCB specimen and the propellant part was analyzed respectively. Meanwhile, the fracture morphology of DCB specimen was analysed. The results show that the improved specimen can effectively characterize the properties of the propellant/liner interface. The propellant/liner interface shows obvious temperature and strain rate dependence, and the effect of temperature on the propellant/liner interface performance is more significant than that of loading rate. The deformation at the propellant/liner interface of the DCB specimen can reach about 50%, and the interface fracture mode of propellant/liner is cohesive fracture.