张弦巨型网格结构动力特性研究

Research on Dynamic Performance of String Reticulated Mega-structure

针对由张弦梁概念和巨型网格结构组合而成的一种新型超大跨空间结构,通过模态分析研究结构的动力特性,首先将主体结构单独承载和子结构协同承载两种情况下张弦巨型网格结构的前12阶自振周期及相应振型进行比较,然后对结构首阶各向振型的出现次序及相应自振周期进行了主体结构矢跨比、桁架梁高度、撑杆长度、预应力大小等一系列参数分析并与未布索结构作对比,详细研究了结构各方向刚度随不同参数改变时的变化情况。结果表明,主体结构单独承载时结构的纵向刚度最弱,子结构的引入能够极大地增强结构水平纵向刚度;预应力体系的引入可以显著提高结构的拱向及竖向刚度。为保证预应力提高结构竖向刚度的效果,主体结构应取较大矢跨比,且桁架梁高度的取值不宜太大。

For a new type of string reticulated mega-strueture based on the concept of beam string structure and cylindrical reticulated mega-structure, the structural dynamic performance was in- vestigated by using modal analysis method, and comparison of the 1st to 12th periods and corre- sponding vibration modes were then made between the case of the main structure bearing loads a- lone and the case of the main structure bearing loads cooperative with the substructures. In a se- ries of parameter analysis, we further studied the order of the first modal appearance and corre- sponding periods. Parameters include the ratio of rise to span, the height of the latticed 3D beams, the strut length and the pre-stressing force. Results indicate that the longitudinal stiff- ness of the structure is weakest, the introduction of the substructures can significantly enhance the horizontal longitudinal stiffness of the structure, and the pre-stress system can improve the horizontal and vertical stiffness of the structure effectively. In addition, in order to ensure the effect that the pre-stress can improve the vertical stiffness of the structure, the ratio of rise to span should be high while the height of the latticed 3D beams should not be too great.