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强度准则是炸药材料破坏力学的重要组成部分,是炸药部件承载能力评估的基础.基于单轴加载技术,设计了圆柱试件的端部约束压溃试验方法,对HMX基PBX和TATB基PBX两种材料进行了复杂应力下的强度失效试验.依据试验边界条件和平均测试结果,利用有限元方法定量分析了试件内部的应力场分布,最后采用最先破坏处的三向主应力数据分析了四种典型强度准则在三轴压缩PBX强度分析中的适应性.就描述精度来看,Mohr-Coulomb准则最优,误差在15%以内,Twin-shear准则和Drucker-Prager准则次之,现常用的Uniaxialstrength准则相对最差.就安全阈度来看,Uniaxial-strength准则最优,两种材料中安全阈度均超过75%,MohrCoulomb准则和双剪Twin-shear准则次之,Drucker-Prager准则相对最差.总的来讲,在三轴压缩应力状态下,Mohr-Coulomb准则可用于描述HMX基PBX的表观强度上限和TATB基PBX的表观强度下限,Twin-shear准则可用于描述TATB基PBX的表观强度上限.
The strength criterion is an important part of dynamical materials’ destructive mechanics, which is the basis of carrying capacity assessment of explosive parts.According to the uniaxial loading technology, the end restraining crushing test method of cylindrical specimens is designed, and the HMX-based PBX and TATB-based PBX Based on the experimental boundary conditions and the average test results, the finite element method was used to quantitatively analyze the stress field distribution inside the specimen. Finally, the three-way principal stress data of the first failure point were used to analyze the strength failure test. Four kinds of typical strength criteria in the triaxial compression PBX strength analysis. To describe the accuracy, the Mohr-Coulomb criterion is optimal, the error is less than 15%, Twin-shear criterion and Drucker-Prager criterion second, now commonly used The Uniaxialstrength criterion is the worst, and the Uniaxial-strength criterion is the best in terms of safety threshold, both of them have more than 75% safety threshold, MohrCoulomb criterion and Twin-shear criterion, followed by Drucker-Prager criterion In the worst case, the Mohr-Coulomb criterion can be used to characterize the upper bound on the HMX-based PBX and the lower bound on apparent TABB-based PBX under triaxial compression stress It is used to describe the upper limit of the apparent strength of the TATB based PBX.