Shear Mechanical Properties Prediction Method and Simulation Calculation Model of Aging NEPE Propellant Adhesive Interface

ABSTRACT To investigate the effects of long‐term vertical storage on the shear mechanical properties of NEPE motor adhesive interfaces, high‐temperature accelerated aging tests were conducted at three temperatures (40°C, 50°C, and 60°C). Constant‐velocity shear tests were performed on the NEPE propellant adhesive interfaces before and after aging. On the basis of experimental results, a shear damage model for the NEPE propellant adhesive interface was developed by integrating a bilinear cohesive zone model with the Arrhenius equation to account for aging effects. A shear damage cohesive unit that explicitly considers aging was constructed using the UMAT subroutine, and its validity was verified through conventional finite element analysis. The results indicate that the shear damage strength of the NEPE propellant adhesive interface and the ratio of shear cohesive energy density before and after damage are positively correlated with aging temperature and aging time. Conversely, the strain at damage initiation is negatively correlated with these aging parameters. Moreover, the location of shear damage shifts progressively from the propellant to the liner‐insulation interface as aging progresses. The developed cohesive unit effectively simulates both shear damage and aging behavior in the NEPE propellant adhesive interface.