基于并行流变框架HTPB推进剂本构模型研究

基于并行流变框架提出了一种能够表征HTPB推进剂材料非线性变形行为的本构模型。基于Yeoh超弹性模型和Boyce流变模型建立了两节点HTPB推进剂本构模型；开展了HTPB推进剂定速单轴拉伸实验和松弛实验，利用单轴拉伸实验数据获取了本构模型参数，并对材料松弛行为进行了理论计算，结果表明，模型计算结果与和实验数据一致性超过90%。应用三维有限元法，采用本文模型、基于Prony级数的线性黏弹性模型和工程中使用的线弹性模型对拉伸实验和松弛实验进行了仿真分析，结果表明，在拉伸实验中当应变小于10%时三者一致性较好，大于10%时，所提本构模型可准确预示材料的变形行为，在松弛实验中本模型计算结果与实验数据一致性远高于基于Prony级数的线性黏弹性模型。理论分析和三维有限元仿真结果均表明，所建立的本构模型可以准确捕捉HTPB推进剂材料的非线性行为，可用于固体火箭发动机推进剂结构预示分析。

HTPB Propellant Constitutive Model Based on Parallel Rheological Framework

In this paper, a constitutive model to characterize the non-linear deformation behaviour of HTPB propellant was proposed based on parallel rheological framework. Firstly, a two-net HTPB propellant constitutive model was established based on the Yeoh hyperelastic model and the Boyce rheological model. Secondly, uniaxial tensile and relaxation experiments were carried out in constant velocity. The uniaxial tensile experimental data were used to obtain the parameters of the constitutive model and the results showed that the agreement between the model calculation results and experimental data exceeded 90%. Finally, the three-dimensional finite element method was applied to simulate the tensile and relaxation tests using the non-linear constitutive model, the linear viscoelastic model based on the Prony series and the linear elastic model used in engineering. The results showed that the agreement among the three models was good in the tensile test when the strain was less than 10%. The proposed constitutive model could accurately predict the deformation behaviour of the material when strain was greater than 10%. In the relaxation test, the agreement between the calculated results and the test was much higher than that of the linear viscoelastic model based on the Prony series. The results of both theoretical analysis and three-dimensional finite element simulation showed that the developed constitutive model could accurately capture the non-linear behaviour of HTPB propellant material and could be used for prediction analysis of solid rocket motor propellant structures.