Microstructural simulation of initial particle-matrix interfacial defect in HTPB solid propellants

Abstract

Impregnation capability at particle-matrix interfacial deteriorates during the preparation of composite solid propellant due to manufacturing and environmental factors, which leads to the initial defects in the HTPB solid propellant. In the present work, the effects of initial particle-matrix interfacial defects on the debonding, nucleation, and crack propagation of the composite solid propellant is investigated experimentally and numerically. A random packing model is developed based on the molecular dynamics method by embedding AP particles in the HTPB propellant. The strength of particle-matrix interface obeys Weibull function. Moreover, a zero-thickness cohesive element is used to simulate the particle-matrix interfacial debonding and matrix rupture. According to the simulation and experiment results, the initial interface defects makes a marked effect on the initial modulus, limit strength and elongation at fracture of the composite solid propellant. The initial modulus, limit strength and elongation at fracture of the composite solid propellant decrease with the increase of the initial interface defects.