Mesoscopic structure modeling and numerical simulation of debonding process of composite solid propellants

To study the damage evolution law of composite solid propellants, the mesoscopic structure model for HTPB(hydroxylterminated polybutadiene) propellants was established based on the molecular dynamics particle filled algorithm. The adhesive contact method was employed for the adhesion interface between AP(ammonium perchlorate) particle and HTPB matrix, instead of the traditional cohesive element method, and the HookeJeeves optimization algorithm was used to identify the parameters of cohesive zone model of the particles/matrix interface. Then both bilinear cohesive zone model and the selfdefined exponential cohesive zone model were employed to simulate the damage evolution process for the interface of AP particle and HTPB matrix, including the initiation, development, gathering and macroscopic crack. The numerical simulation curves and experimental curves were compared, showing that the exponential cohesive zone model can better describe the debonding process between the AP particles and HTPB matrix under the uniaxial tension loading. Finally, the multistage loading experiment was compared with the simulation curve. It was found that the change trend was consistent and the tolerance was less than 10%, demonstrating the high reliability of mesoscopic model and the interface parameters accuracy.