考虑初始缺陷的HTPB推进剂粘超弹本构模型

为研究端羟基聚丁二烯(HTPB)推进剂存在初始缺陷对其宏观力学性能的影响,对定制的不同界面缺陷含量的HTPB推进剂开展了多步松弛和单轴拉伸试验。获得了HTPB推进剂的平衡响应曲线和拉伸曲线。采用Ogden模型拟合了不含缺陷的HTPB推进剂的平衡响应曲线,引入应变率参数M来描述HTPB推进剂单轴拉伸曲线的率相关特性。通过该曲线拟合,得到了不含缺陷的HTPB推进剂的粘超弹本构模型参数。考虑了缺陷的影响,通过引入初始缺陷损伤因子f,构建了含初始界面缺陷的HTPB推进剂的粘超弹本构模型,分步拟合得到了所有模型参数。最后,用本研究所建模型预测了单轴拉伸载荷下的HTPB推进剂的宏观力学性能,结果表明,预测结果与试验结果一致,二者最大偏差仅为4.4%,验证了模型的可靠性。

Visco-hyperelastic Constitutive Model of HTPB Propellant Considering Initial Defects

To study the effect of hydroxyl terminated polybutadiene(HTPB) propellant with initial defects on its macroscopic mechanical properties, the multi-step relaxation and uniaxial tensile tests of the home-made HTPB propellants with different content of initial interface defect were conducted and the equilibrium response curve and tensile curves of HTPB propellant were obtained. The equilibrium response curve of HTPB propellant without initial defects was fitted by Ogden model. The strain rate parameter M was introduced to discribe the rate dependence characteristics of uniaxial tension curves of HTPB propellant, and the parameters of the visco-hyperelastic constitutive model of HTPB propellant without defects were obtained through fitting the curves. The influence of initial defects was taken into consideration, the visco-hyperelastic constitutive model of HTPB propellants with initial interface defects was constructed by introducting the initial damage factor f and all model parameters were obtained by fitting step by step. Finally, the macroscopic mechanical behavior of HTPB propellant under uniaxial tension loading was predicted by the model established by this investigation. Results show that the predicted results are consistent with the experimental ones, the maximum deviation between the two is only 4.4%, which confirms the reliability of the model.