Time‐Stress‐Aging Superposition Principle for Predicting Long‐Term Creep Behavior of <scp>HTPB</scp> Propellants Under Accelerated Storage

ABSTRACT To investigate the mechanical properties of solid propellants during long‐term storage, a series of accelerated aging tests were conducted at 70°C for intervals of 15, 30, 45, and 60 days. After these aging tests, short‐term creep tests were performed on both aged and unaged hydroxyl‐terminated polybutadiene (HTPB) propellants, subjected to varying stress levels. The effects of aging time and loading stress on the creep properties of the propellants were analyzed. The principle of time‐stress‐aging time superposition is derived based on the principles of time‐stress superposition and time‐aging time superposition. The results were compared with the long‐term creep test. The results demonstrate that the creep compliance of HTPB propellant diminishes substantially with an increase in aging time at a constant stress level. The long‐term creep behavior of HTPB propellant can be analyzed by the properties of lower load and longer aging time.