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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 study the type Ⅰ fracture properties of the modified double-base propellants, the three-point bending test and uniaxial tensile test of the propellant materials were carried out. The fracture strength and fracture energy parameters were obtained preliminarily. Based on the cohesion model, the material fracture constitutive equation was constructed and applied to the finite element simulation analysis of three-point bending fracture. The load-displacement curves of the loading point were obtained. The cohesion parameters were corrected by the inversion optimization algorithm to obtain the final accurate model parameters. To verify the accuracy of the model, three-point bending tests and simulations at different initial crack lengths were carried out. The results show that the model can well describe the load-displacement and crack propagation characteristics during the actual crack propagation. The error between the simulation results and the experimental results is less than 7.6%, which proves the effectiveness of the model.