关键词: 冲击波载荷, 预制损伤, 固体推进剂, 失效模式

Abstract: Solid propellants with crack defects are susceptible to crack propagation under shock wave loading during their service life, significantly compromising their structural integrity. To investigate the dynamic mechanical response and defect-induced damage evolution of hydroxyl-terminated polybutadiene (HTPB) propellants under varying shock wave intensities, a shock tube apparatus was employed, combined with schlieren imaging and 3D digital image correlation (3D-DIC) techniques. Shock wave loading experiments were conducted on both defect-free and crack-defected propellant specimens within a pressure range of 0.3 to 0.9 MPa, capturing the dynamic deformation and damage evolution processes. The results indicate that the deformation of the defect-free specimens exhibited a parabolic profile, with the maximum deformation showing an approximately linear relationship with the applied shock pressure. The specimens with different crack depth show different crack growth under 0.9 MPA impact pressure, and multiple impacts will result in superimposed damage. The critical failure crack depth ratio is 50% ~ 75% .Scanning electron microscopy images revealed that matrix cracking, particle debonding, and particle fracture were the primary failure mechanisms. These findings provide valuable insights for assessing the structural integrity of solid rocket motors under ignition shock conditions.

Key words: shock wave load, prefabricated damage, solid propellant, failure mode