Mechanical Properties of Composite Solid Propellant with Initial Defects

Abstract

To study the mechanical properties of composite solid propellant with initial interface defects, the mesoscopic structure model for HTPB (hydroxyl-terminated polybutadiene) propellant was established based on the periodicity assumption and molecular dynamics particle filled algorithm. The cohesive element method was employed for the adhesion interface between AP (ammonium perchlorate) particle and HTPB matrix, and the bilinear cohesive zone model was used to describe the mechanical response of the interface elements. Then, the space position and mechanical properties of the deficient interface were defined by the homemade program, and the macroscopic mechanical response of the propellant with interface defects was calculated based on the commercial finite element software ABAQUS. The stress-strain nephogram indicates that the interface with defects is earlier to debond and this also accelerates the process of the propellant fracture failure. The numerical simulation curves of the propellant with different contents of defects are compared. The result shows that the existence of interface defects reduces the mechanical properties of the propellant, and the higher defect contents obviously causes the lower mechanical properties. With the increase of the content of defects, the initial modulus and tensile strength of the propellant are decreased.

Keywords

• composite solid propellant
• initial interface defects
• cohesive zone model
• finite element simulation