Abstract: Dewetting has a great influence on the mechanical properties of composite propellant. The dewetting damage evolution at different tensile rates is researched using a constant speed tension and CCD optical microscope. A viscoelastic constitutive model was established. A microscopic reason is analyzed to interpret the development of micromechanical properties based on the micromechanics and interface mechanics theory. The results show that the dewetting between particles and matrix is an important factor on the macroscopic nonlinear stress-strain curves, and leads to the decline of Poisson's ratio. The damage of interfacial dewetting is determined by strain, and has a certain correlation with strain rate. Poisson's Ratio is also a powerful parameter to quantify the dewetting.

Key words: propulsion system of aviation & aerospace, interfacial dewetting, HTPB propellant, micro-structure, constitutive model, Poisson’s ratio