考虑分子链密度的固体火箭发动机粘接界面强度评价方法

Solid rocket motor is a composite structure with multi-material and multi-interface, and the bonding strength between the grain and the case plays an important role for structure integrity analysis of the motor.To accurately evaluate the launch reliability in various storage conditions,it is urgent to obtain an accurate evaluation method for the bonding interface performance.In this paper,the mechanical response evolution of the interface testing samples before and after loading with different stress and time was studied by experiments,and a method for evaluating the bonding interface strength based on molecular chain density was proposed.The results show that the previous loading history (loading stress and loading time) and the current loading conditions during testing (including tensile speed and temperature) can be been linearly decoupled. The interface response after experiencing different loading conditions can be translated equivalent to the response of the testing sample under the condition of no damage,and the shift factor is related to the decrease of molecular chain density during loading.Compared with the ultimate stress,the interface energy can better describe the bonding strength. The predicted strength evaluation method is in good agreement with the experimental results,which provides an alternative method to evaluate the bonding reliability between the grain and the case during storage.