爆炸荷载下网壳结构的动力响应及泄爆措施

Dynamic response and explosion relief ofreticulated shell under blast loading

以有限元软件ANSYS/LS-DYNA为平台,建立了40 m跨度K8型单层球面网壳在中心TNT爆炸荷载作用下的精细化有限元数值分析模型。在网壳结构各组成部分的单元选取、钢材本构关系与参数确定、网格尺寸选择与划分方式、结构对称性应用等方面进行了探索,保证了有限元动力分析的精度与可行性。通过比较网壳结构的塑性应变及其发展程度、杆件应变与位移等结果获得了不同网壳矢跨比、炸点距离以及屋面板厚度下的结构爆炸响应规律;以屋面板作为网壳结构的泄爆方式,研究了屋面板开洞率、开洞数量及洞口分布、洞口位置对结构响应的影响。总结了中心爆炸荷载作用下大跨度单层网壳结构的动力响应结果、最佳的屋面板泄爆布置方案,为网壳结构的合理抗爆及防御设计提供了理论依据。

Dynamic finite element software ANSYS/LS-DYNA was used to set up the fine finite element model for Kiewitt 8 single-layer reticulated shell with a span of 40 m subjected to blast loading located at central point.The selection and determination of material parameters and constitutive models,element types,mesh dimension and generation and the application of symmetric structure were further validated to guarantee the precision and feasibility of dynamic analysis for finite element analysis.The response rules of the structure under blast loading with different rise-span rates,standoff distances and thicknesses of roof boarding were obtained through the comparison of the plastic strain,the plastic development degree and displacement of members.In addition,the effect of different opening rates,opening numbers,opening distributions and opening positions on roof boarding on the response of structure were also studied based on the explosion relief of roof boarding.The response results of long-span single-layer reticulated shell structure under central blast loading were summarized and the optimal layout scheme of openings on roof boarding was put forward,which offers the theoretical basis for reasonable defense design of reticulated shell structure for resisting blast.