Abstract: In order to understand how pre-strain affects the aging mechanical properties of composite solid propellant，the accelerated aging tests of HTPB (hydroxy-terminated polybutadiene binder)propellant under the interaction of thermal and pre-strain were carried out at 70℃. The aging properties of HTPB propellant at different pre-strain levels were researched through uniaxial tensile tests and scanning electron microscope (SEM) experiments of tensile fracture surfaces. The results show that the oxidative crosslinking reaction of binder matrix is the major aging mechanism of HTPB propellant at researched pre-strain range (≤15%) regardless of different pre-strain levels. At the same aging time，there is a critical pre-strain value that affects the mechanical properties of HTPB propellant. When the aging pre-strain is higher than the critical pre-strain value，the dewetting phenomenon of AP and HTPB matrix bonding interface and the tearing damage phenomenon of binder matrix is evident in tensile fracture surface.

Key words: HTPB propellant；Aging；Mechanical properties；Dissipated energy density

摘要： 为了研究预应变对复合固体推进剂老化性能的影响，针对HTPB复合固体推进剂开展了70℃热力耦合加速老化试验，通过单轴拉伸力学性能测试及拉伸断面扫描电镜试验研究了不同预应变作用下HTPB推进剂的老化性能。结果表明:在试验预应变范围内(≤15%)，无论预应变水平多大，随老化时间的延长，粘合剂基体的氧化交联反应是HTPB推进剂的主要老化机理；在相同老化时间，预应变对HTPB推进剂力学性能的影响存在一个损伤阈值，当预应变超过该阈值时，拉伸断面中AP颗粒/粘合剂基体界面“脱湿”及粘合剂基体撕裂损伤现象明显。

关键词: HTPB推进剂；老化；力学性能；耗散能密度