温度对HTPB推进剂疲劳特性的影响

为了研究端羟基聚丁二烯(HTPB)推进剂不同温度下的疲劳特性,进行了不同温度下恒应力控制的疲劳循环加载试验。以峰值应变作为损伤因子,基于损伤力学和粘弹性理论,建立了HTPB推进剂含温度效应的疲劳损伤三阶段演化模型。结果表明,随着温度的升高,材料的疲劳寿命缩短,疲劳断裂应变增大。疲劳过程中的峰值应变具有明显的三阶段演化规律:初始变形阶段、稳定发展阶段和加速阶段。建立的三阶段演化模型克服了两阶段模型不能考虑宏观裂纹扩展的缺点。拟合模型参数,运用线性回归的方式预测了213 K和333 K的理论结果,该结果和试验结果较为一致,因此,它可以很好地表征材料的损伤演化规律。

Effect of Temperature on Fatigue Properties of HTPB Propellant

To study the fatigue properties of hydroxyl terminated polybutadiene (HTPB) propellant at different temperatures,the constant stress control fatigue cyclic loading tests at different temperatures were carried out.Taking peak strain as damage factor,based on damage mechanics and viscoelastic theory,a three-stage model of fatigue damage with temperature effect of HTPB propellant was established.The results show that with increasing temperature,the fatigue life of materials decreases,the fracture strain increases.The peak strain in the process of fatigue obviously has three stages of evolution:initial deformation stage,stable development stage and acceleration stage,which is the macro-behavior of material damage.The three-stage model established overcomes the shortcomings of two-phase model that can't consider macroscopic crack propagation.By fitting the model parameters,the theoretical results of 213 K and 333 K are predicted by linear regression method,which are in good agreement with the experimental results,therefore it can be used to characterize the damage evolution law of materials very well.