Abstract: In order to study the effects of temperature and loading rate on HTPB propellant fracture capability，the low temperature fracture toughness experiment of HTPB propellant was carried out. The values of propellant fracture toughness at different temperature and loading rate with Ⅰ mode crack were obtained，and the effects of specimen thickness on the fracture toughness were investigated. The results show that the value of fracture toughness continuously increases with the decreasing of temperature and the increasing of loading rate，and a linearity relationship exists between the fracture toughness and the logarithm of the loading rate. The lower the temperature，the more notable the influence of the fracture toughness by the changing of the loading rate . All at normal temperature and -40℃，the fracture toughness of thick specimen is greater than that of thin specimen，and at low temperature the change is more obvious. At last，a master curve of quadratic function for the fracture toughness has been obtained.

Key words: HTPB propellant；Low temperature；Fracture toughness；The time-temperature superposition principle

摘要： 为研究温度和加载速率对HTPB推进剂断裂性能的影响，开展了HTPB推进剂低温断裂韧性试验，测定了不同温度和加载速率下含Ⅰ型裂纹推进剂试件的断裂韧性值，并研究了试件厚度对断裂韧性值的影响。结果表明:随着温度的降低和加载速率的增加，推进剂断裂韧性值逐渐增大，且断裂韧性值与加载速率的对数呈线性关系，温度越低，加载速率的变化对断裂韧性的影响越显著；在常温和-40℃下厚试件的断裂韧性值比薄试件要大，并且低温下这种变化更明显。最后得到了推进剂断裂韧性的二次函数主曲线。

关键词: HTPB推进剂；低温；断裂韧性；时间温度等效原理