铝合金半刚性椭圆抛物面网壳静力稳定性分析

STATIC STABILITY OF ALUMINIUM SINGLE-LAYER ELLIPTICAL PARABOLIC LATTICED SHELL WITH SEMI-RIGID JOINTS

针对目前铝合金单层网壳结构中节点形式过于单一的局面,该文首先研发出了一种新型铝合金半刚性节点——柱板式节点。获得了柱板式节点绕强轴、弱轴和扭转三个方向的弯矩-转角曲线,并将其引入到网壳杆件单元模型中,建立了半刚性节点工字型杆件椭圆抛物面网壳的数值分析模型。在此基础上,考虑节点强轴刚度、节点弱轴刚度、节点扭转刚度及跨度和矢跨比等参数影响,对半刚性节点高强铝合金椭圆抛物面单层网壳进行了弹塑性全过程分析,得到了各参数对网壳极限承载力的影响规律,并详细地考察了网壳失稳时的变形形态。研究发现:网壳失稳时,网壳中的柱板式节点均处于弹性状态,说明柱板式节点有较好的刚度,网壳的失稳为伴随杆件扭转屈曲的局部失稳。

The joint type used in an aluminum single-layer latticed shell is limited. Therefore, a new type of aluminum joint called Column Plate Joint was developed for single layer latticed shells. The moment-rotation curves about three axes were obtained with ABAQUS. By integrating the moment-rotation curves into the numerical model of reticulated domes with I-shaped bars, the finite element models of aluminum single-layer elliptical parabolic latticed shells with semi-rigid joints were established with ANSYS. The research is carried out on the mechanical behavior of the shells based on different parameters, including the joint bending stiffness, joint torsional rigidity, and the ratio of rise to span. The critical load and the deformation of the structures were investigated in detail. The analytical results show that： i） the Column Plate Joint has good stiffness; ii） all of the Colunm Plate Joints in the shells are in an elastic state when the shells failed; iii） the aluminum single-layer elliptical paraboloid latticed shells failed because of the local torsional buckling of the members.