Abstract: Accelerated aging tests at the conditions of 3%，6% and 9% strain levels were conducted on HTPB propellant with the goal of studying effects of constant strain on its maximum elongation. An elongation aging model was developed to analyze the effects of constant strains and temperature on model parameters by fitting the experimental data. Results show that physical tension effect caused by constant strains can increase elongation significantly，and the increasing amplitude exhibits a linear relationship with aging temperature and pre-strains. Physical tension effect shows obvious characteristics of stress relaxation with aging times at various constant strains，increasing elongation exponentially. There is a critical temperature between 65℃ and 70℃ in the aging process of propellant. Constant strains have almost no effect on elongation aging rate below critical temperature，but they decrease elongation aging rate above critical temperature.

Key words: HTPB propellant； Maximum elongation； Accelerated aging tests； Constant strain； Physical tension； Aging model

摘要： 为研究定应变对HTPB推进剂最大延伸率的影响，开展了3%，6%和9%定应变水平下HTPB推进剂方坯加速老化试验，建立了推进剂最大延伸率的老化模型，并通过试验数据拟合，分析了定应变和温度对各模型参数的影响规律。结果表明:定应变的物理拉伸作用对推进剂的最大延伸率有明显的提升作用，其提升幅值与定应变水平和老化温度呈线性关系。物理拉伸对最大延伸率的提升作用具有明显的力学松弛特性，近似呈指数规律。推进剂在老化过程中存在一介于65℃与70℃之间的临界温度，当老化温度低于临界温度时，定应变对推进剂的延伸率老化速率几乎没有影响；老化温度高于临界温度时会降低延伸率老化速率。

关键词: HTPB推进剂；最大延伸率；加速老化试验；定应变；物理拉伸；老化模型