考虑重力影响的单层网壳冲击相似律及数值验证

Gravity-Based Impact Comparability Rule of Single-Layer Reticulated Shells and Its Numerical Verification

考虑重力作用和材料的应变率效应,根据量纲分析,推导出单层网壳在顶点受冲击物冲击的相似律表达式,并在此基础上,提出可通过特别制备材料或添加配重的方法来满足相似条件.采用非线性有限元软件LS-DYNA建立与已有文献一致的模型,对比试验结果,验证数值方法的可靠性;建立凯威特-联方型单层网壳分析模型,以节点位移为考察量,分别对提出的两种方法进行验证.结果表明:文中提出的两种方法均能较好地预测原型的位移,相对误差绝对值分别小于15%和12%;均能准确预测网壳的倒塌模式,特别是工程关注的整体倒塌;添加配重的方法具有更高的精度和可操作性.

Through the dimensional analysis, a comparability rule expression of single-layer reticulated shells sub-jected to a vertex impact is derived in this paper, which considers the gravity and the strain-rate effect of relevant materials. On this basis, two methods of preparing material specially and adding extra mass are proposed to meet the scaling requirements. Then, a model according well with available literaturesis constructed by using the non- linear finite element software LS-DYNA, and it is proved to be reliable by comparing the experimental results with- the simulation ones. Finally, two analytical models of Kiewitt-Lamella single-layer reticulated shells are respec- tively constructed to verify the proposed two methods by comparing their node displacements. The results show that the proposed two methods can both accurately predict the displacement of the prototype, with the relative error ab- solutes of less than 15% and 12% respectively, and they can both accurately predict the collapse modes of the pro- totype, especially the whole collapse, and that the method of adding extra mass is better in terms of precision and maneuverability.