ABSTRACT This study investigates the structural integrity of a four‐component hydroxyl‐terminated polybutadiene (HTPB) propellant under vibrational loading through integrated experimental and numerical approaches. Mechanical and fatigue tests on aged specimens revealed changes in mechanical properties and energy dissipation behavior. Dynamic mechanical analysis conducted on 2‐years‐aged specimens at 0.5–2 Hz frequencies demonstrated time‐dependent variations in storage modulus and loss factor, enabling the development of an energy dissipation model. Micro‐CT characterization identified fine surface and internal cracks, while a high‐fidelity 3D mesoscale model was established using programming techniques. The results demonstrated that the dynamic storage modulus exhibits significant time‐ and frequency‐dependent nonlinear characteristics, with the most substantial changes occurring at 10 min before stabilization. Micro‐CT observations revealed predominant ammonium perchlorate (AP) particle fractures in specimen central regions, while finite element analysis indicated maximum displacement at AP particle locations, correlating with fracture susceptibility. Changes in natural frequency and resonance peaks suggested increased AP volume fraction and reduced sphericity, with numerical predictions showing good agreement with experimental observations.
Zhu et al. (Mon,) studied this question.