耦合约束布置对框架式高塔动力特性的影响

Effect of Coupled constraint Arrangement to Dynamic Characteristics of Framed High Tower

由框架和自支承的独立大长径比高塔通过耦合约束连接而组成的框架式高塔是石化工程中的一种特殊结构形式。在进行风载和地震作用分析时,都将涉及到其固有动力特性。以某石化工程中一实例为对象模型,对多种耦合约束布置形式下的框架塔进行了动力特性分析。结果表明,框架与塔之间的变形耦合约束布置对框架塔的基频模态和自振周期的影响微小,而对高阶模态和周期的影响则十分显著;框架塔具有在高阶振型中整体结构模态与局部(子结构)模态交替出现、局部模态被激活的顺序随约束设置后整体刚度的变化而变化的组合结构特征。分析同时指出,框架塔设备这种形式的工程设计不能按单塔或简单质量折算法来计算,而应该按多体系组合结构进行分析计算。

Framed high-column is a special kind of vessel used in petro-chemical industry, which is a composite structure of frame and long slender self-supporting column connected by deformation coupling constraints. Its inherit dynamics behaviors are involved in wind seismic action analysis. The analysis of dynamic characteristics for real framed high-column with multi deformation coupling constraint distribution were carried out in this paper. The results indicated that the coupling constraint distribution between frame and column have a little influence on base-frequency mode and period of vibration but great effect on high order mode and period; Framed high-column have a behaviors of composition structure under high order mode, in which integral mode and local（sub-structure） mode appear alternately; and the sequence change of local mode is activated with the change of the rigidness of constrained integral structure. Meanwhile, it has indicated that this kind of structure shall not be calculated as an isolated column model or by using simply mass condensed method, and multi-system structure analysis method should be applied in calculation and analysis.