【作者】 李晓；

【导师】 孙毅；

【作者基本信息】 哈尔滨工业大学 ， 固体力学， 2014， 硕士

【摘要】 钻地弹中的内部装药是一种粘弹性含能聚合物，侵彻过程中产生的冲击波对内部装药的安定性构成了严重威胁，内部装药有可能在未到达指定侵彻深度时提前自爆，从而使钻地弹失去其原有的杀伤力。本文使用有限元程序对含内部装药结构的钻地弹侵彻半无限混凝土靶问题进行了模拟，得到了内部装药在侵彻过程中应力波的传播规律，并通过增加缓冲结构的方式有效降低了内部装药在侵彻过程中的应力水平，对能量耗散进行了推导，给出了内部装药的耗散能分布。本文首先介绍了在分析侵彻问题时使用广泛的空腔膨胀理论和侵彻深度计算公式，阐述了使用有限元方法求解动力学问题时所用到的基本理论。在此基础上，使用有限元程序ANSYS/LS-DYNA，对钻地弹侵彻半无限大混凝土靶问题进行数值模拟，通过与实验结果和理论公式计算结果相对比的方法，验证了有限元模型的正确性。然后，对钻地弹内部装药在侵彻过程中的应力波传播规律进行了分析，发现计算结果与前面的理论分析一致。为了降低内部装药在侵彻过程中的应力，考虑在内部装药前端增加缓冲结构，缓冲结构材料采用泡沫铝。对比有无缓冲结构情况下内部装药的应力，发现前端缓冲结构能够有效降低内部装药前端的应力。结合前面对内部装药中应力波传播规律的分析，对缓冲结构进行优化，对比优化前后内部装药的应力，发现优化效果明显。最后，根据内部装药模型中单元的应力时间曲线变化规律，推导在常应力和交变应力共同作用下粘弹性材料的能量耗散求解公式，并给出了整个装药结构的耗散能分布。更多还原

【Abstract】 The internal grain of an EPW (Earth penetration weapon) is a kind of viscoelasticand energetic polymer. Shock wave in the process of penetration threatens the stabilityof internal grain. The grain may explode accidentally before the EPW reaches itsoriginal specified depth. In this thesis, the numerical simulations based on finite elementmethod were conducted to analyze a problem that a projectile containing internal grainpenetrating a half-infinite concrete target. Stress wave progression in the viscoelasticgrain was analyzed. Cushioning structure was applied and the stress in grain elementwas lowered efficiently. Formula to calculate the energy dissipation in grain wasdeduced and it led to the distribution of dissipated energy in the structure.First, cavity-expansion theory which was widely used and formula of penetrationdepth were introduced; the dynamics fundamental theory of finite element method wasstated. Based on them, numerical simulations of an EPW penetrating concrete targetswere conducted by the FEM software. Comparison among results of the numericalsimulation, experiments and formulas proved accuracy of the FEM model.Secondly, the thesis focused on analysis of the stress wave progression in grain inthe process of penetration. Then results of simulations were checked and they matchedthe former theoretical analysis.In order to decrease the stress in grain, cushioning structure was added which wasmade up with aluminum foam. By compared simulations, stress of the front-end of grainwas obviously reduced with the existence of cushioning structure. In consideration ofthe analysis of stress wave, the cushioning structure was optimized. Results ofnumerical simulations demonstrated the validity of the optimization.Finally, according to the analysis of stress wave in grain, the stress could bedecomposed into constant part and repeated part. Energy dissipation formulas in grainwere deduced and the distribution of dissipated energy was obtained.更多还原