Experiment Study of Failure Mode of HTPB/AP Interfacial Debonding

Macro- and micro-mechanics viscoelastic model for composite solid propellant was proposed. The adhesive energy has an important influence on the behavior of composite solid propellant. It was shown that as the adhesive energy increases, the strength of propellant increases. Meanwhile, the mechanical response of HTPB/AP interface is modeled by the bilinear cohesive zone model describing the debonding process. According to the cohesive zone model, one-side AP tester and sandwich apparatus were designed to determine the value of adhesive energy between the binder and AP, respectively. Based on the sandwich apparatus, the energy per unit area of completely interfacial debonding without MAPO is equal to 14 J/m
²
, and lower limit of adhesive energy per unit area of completely interfacial debonding with MAPO is determined. According to the test result of one-side AP and the numerical simulation of macro- and micro-mechanics viscoelastic algorithm, it can conclude that the failure mode of HTPB/AP in composite solid propellant is the similarly interfacial debonding, instead of fully interfacial debonding.