基于内聚力模型的改性双基推进剂断裂特性研究

Research on Fracture Property of CMDB Propellant Based on Cohesive Zone Model

为了研究改性双基推进剂的Ⅰ型断裂性能,进行了该推进剂材料的三点弯曲试验及单轴拉伸试验,初步获取了材料的断裂强度及断裂能参数。基于内聚力模型构建材料断裂本构方程,应用于三点弯曲断裂有限元仿真分析,得到仿真加载点载荷-位移曲线,并采用反演优化算法对内聚参数进行修正,获取最终准确模型参数。为验证模型准确性,进行了不同初始裂纹长度下的三点弯曲试验及仿真。结果表明模型能够较好地描述实际裂纹扩展过程中的载荷-位移特性及裂纹扩展特性,仿真结果与试验结果误差小于7.6%,证明该模型的有效性。

In order to investigate the type Ⅰ fracture property of a kind of composite modified double-base propellant,three-point bending test and uniaxial tensile test were conducted to get the fracture strength and the fracture energy. The loading point force-displacement curves were obtained by the finite element analysis of the three-point bending fracture process,and the fracture constitutive equation based on the cohesive zone model was embedded in this finite element program. The parametric inversion method was used to modify the cohesive parameters,and the accurate parameters of the model were finally acquired. Three-point bending test and simulation with different initial crack length were conducted to verify the fracture model. The results show that the model can describe the load-displacement property and crack propagation property well,the maximum deviation between test and simulation is less than 7.6%,which certificates that the model has the validity and some reference values for the propellant fracture research in solid rocket motor.