冲击载荷作用下单层球面网壳结构的破坏和温度效应

庞凯 胡亚超 席丰 谭英华

摘要： 基于材料的损伤和失效准则，考虑重物冲击和受火温度对钢材性能的影响，运用有限元软件Abaqus分析K8型单层球面网壳在不同温度范围受到冲击载荷时的失效模式。对693个网壳算例进行分析，根据网壳的竖向变形和塑性发展情况，总结K8型单层球面网壳在冲击载荷作用下的6种破坏类型和失效模式分布。研究结果表明：温度对网壳结构在冲击作用下的稳定性有较大影响;在冲击物质量和速度一定的前提下，当火灾温度达到某个限值时，网壳出现整体倒塌破坏;当火灾温度达到400 ℃时，结构的抗冲击能力明显降低;随着冲击物质量和速度的增加，网壳变形模式不再随着温度的升高发生明显变化，此时网壳失效类型以剪切破坏为主。

关键词： 网壳;火灾;失效模式;动力响应;金属损伤;失效准则;有限元

Abstract： Based on the damage and failure criteria of the material， the failure modes of K8 singlelayer reticulated dome subjected to impact load at different temperature are analyzed by finite element software Abaqus， in which the influence of heavy impact and fire temperature on steel properties is considered. The 693 cases are analyzed， and the vertical deformation and plastic development of the reticulated dome are analyzed， and then the 6 failure types and the failure mode distributions of the K8 singlelayer reticulated dome under impact loadings are summarized. The results show that： the temperature has a great influence on the stability of reticulated dome under impact;under the premise of a certain impact mass and velocity of the impact object， the reticulated dome collapses while the fire temperature reaches a certain limit;the impact resistance of the structure decreases obviously while the fire temperature reaches 400 ℃;with the increase of the impact mass and velocity， the deformation mode of reticulated dome no longer evidently changes with the increase of temperature， and the failure type of the reticulated dome is mainly shear failure.

Key words： reticulated dome;fire;failure mode;dynamic response;metal damage;failure criterion;finite element

0 引 言

网壳结构具有刚度大、自重轻、整体性能好等特点，被广泛应用于大空间建筑，如体育馆、展览馆等。近些年，针对高大空间建筑结构的袭击事件时有发生，此类建筑一旦遭遇恐怖袭击，将引发严重后果。

国内外许多学者已对高大空间建筑结构进行研究。刘晓等[1]对杭州国际会议中心裙房钢结构桁架体系曲面屋盖进行数值模拟，分析完善结构和带缺陷结构的大位移弹性整体稳定性和弹塑性稳定性，研究结果表明结构的整体稳定因数随载荷步增加而增大，结构的极限承载力可以通过切線刚度的奇异点确定，结构的整体稳定性因数较同种载荷工况下几何非线性整体稳定性因数显著减小。……