A determination method of interfacial mechanical parameters in solid propellants based on cohesive zone model and micromechanical homogenization

High-energy solid propellants are extensively used in aerospace and defense applications, where their structural integrity and failure resistance are largely determined by the interfacial mechanical properties between the binder and energetic particles. Accurately characterizing interfacial mechanical behavior is essential for predicting the macroscopic mechanical properties of propellants and optimizing their structural reliability. In this study, we systematically investigated the interfacial mechanical properties of solid propellants and proposed parameter determination method using the cohesive zone model (CZM), micromechanical homogenization, compact tension tests, and numerical simulations. First, a nonlinear constitutive model of the binder is developed as the foundation for determining interfacial mechanical parameters. A determination method for interfacial mechanical parameters is then developed using the CZM and micromechanical homogenization method. The interfacial mechanical parameters are determined through compact tension experiments and compared with propellant tensile test results to validate the CZM and its parameters. Finally, numerical simulations are used to systematically analyze the effects of interfacial strength and fracture energy on the macroscopic stress-strain behavior of the propellant. The computational results indicate that, below a critical threshold, increasing interfacial strength or fracture energy significantly enhances the propellant's load-bearing capacity and delays the onset of interfacial damage. The interfacial mechanical parameter identification method presented in this study provides theoretical support for optimizing propellant material design, enhancing mechanical performance and structural integrity to meet practical engineering requirements.