爆炸荷载作用下网架结构的动力响应分析

ANALYSIS OF DYNAMIC RESPONSE OF SPACE TRUSS STRUCTURE UNDER BLAST LOADING

将爆炸荷载简化为三角形的冲击荷载,采用有限元将其施加到某跨度为24 m×36 m的某加油站正放四角锥网架结构底面,分析网架结构的动力响应。结果表明:纵向和横向网架节点位移均为中间大,两边小的状态;各个节点的加速度在爆炸发生后经过一定时间的上下波动才开始有较大增长,且角部节点波动频率明显高于其他节点;在爆炸荷载作用下,大部分上弦杆的最大轴力为拉力,部分下弦杆受拉,部分下弦杆受压,下弦杆件受力比上弦杆件大些;边跨轴力分布为中间杆件小,两侧杆件较大;中跨轴力分布为中间杆件大,两侧杆件较小。

The explosion pressure is simplified as the triangular shock load, the bottom surface of a span of 24m×36m gas station is four square pyramid which is applied to space truss structure, using SAP2000 finite element method, analysis of dynamic response of space truss structure. The results showed that： the longitudinal and transverse truss joint displacements are bigger in the middle than both sides, each joint acceleration began to fluctuate after the explosion occurred over a period of time, then grew larger, and the comer joint fluctuation frequency is significantly higher than other joints, under blast loading, most of the upper chord bars are tension, part of the bottom chord bars are tension, part of the bottom chord bars are compression, and the stress of bottom chord bars is bigger than the upper chord bars, the middle chord bars axial force of the side span are smaller than on both sides of chord bars, the middle chord bars axial force of the middle span are bigger than on both sides of chord bars.