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首先,阐述了单层网壳结构在冲击荷载下的能量传递、转换和消耗的过程,并基于能量守恒推导了首次冲击中网壳吸收的能量以及结构动位移简化计算方法。然后,介绍了数值分析方法的算法基础以及求解冲击问题的通用有限元软件ANSYS/LS-DYNA。最后,研究了网壳结构在不同冲击物质量比与速度作用下的动力响应,总结了动力响应与结构能量之间的关系,并与简化计算方法进行对比。结果表明:所推导的网壳能量吸收与结构动位移计算方法是合理的;冲击过程中网壳吸收的能量以及结构响应与冲击物和网壳之间的质量比密切相关;不同的动力响应模式可以利用结构吸收的能量进行区域划分;在不同的冲击能量作用下,冲击力是半正弦或者三角形脉冲;计算所得的杆件应力-应变曲线与材料的本构关系是相符的。
Firstly, the energy transfer, transformation and consumption process of single-layer reticulated shell under impulsive load are described. Based on the conservation of energy, the energy absorbed by the reticulated shell in the first impulse and the simplified calculation method of dynamic displacement are deduced. Then, the algorithm foundation of the numerical analysis method and ANSYS / LS-DYNA, a general finite element software for solving the impact problem, are introduced. Finally, the dynamic response of the reticulated-shell structure under different impact mass ratios and velocities is studied. The relationship between the dynamic response and the structural energy is summarized and compared with the simplified calculation method. The results show that the calculated energy dissipation and dynamic displacement calculation are reasonable. The energy absorbed by the reticulated shell during reloading and the structural response are closely related to the mass ratio between the impacted object and reticulated shell. Different dynamic response modes The energy absorbed by the structure can be divided into zones. The impact force is a half-sine or triangular pulse under different impact energies. The calculated stress-strain curve is consistent with the constitutive relation of the material.