静力凝聚技术对输电铁塔整体模态的影响研究

The study on transmission tower integral modes influenced by static condensation technique

输电塔体系是典型的高柔体系,其整体动力响应与破坏主要由低阶模态控制。如果恰当地判定并忽略某些次要动力自由度而不显著改变输电塔体系的整体低阶模态,就可在保证整体精度和安全性的前提下,大大提高输电塔体系动力响应分析的计算效率。应用静力凝聚技术,对用ANSYS软件建立的输电铁塔原始有限元模型的次要动力自由度进行减缩,得到相应的简化模型。利用ANSYS软件和MATLAB语言编程,对简化前后输电铁塔结构模型分别进行了模态分析和数字地震响应分析。结果表明,采用静力凝聚技术对输电铁塔的原始有限元模型的次要动力自由度进行减缩得到的简化模型是有效的,可用于输电铁塔的动力分析。简化前后输电铁塔模型的前3阶整体模态和顶点位移响应峰值均具有良好的一致性。

The integral dynamic response and failure of a transmission tower structure as typical high flexible system is mainly controlled by low order modes.If ignoring the subordinate dynamic degrees of freedom can not significantly change integral low order modes of the transmission tower structure,the computation efficiency of dynamic response for the transmission tower structure can be greatly improved in guarantees of its integral precision and safety.The finite element model set up by ANSYS for the transmission tower structure is simplified by using the static condensation technique,and then a simplified model is obtained.The modal and earthquake response analysis for the simplified model and original model of the transmission tower structure are made by using ANSYS and MATLAB program.The results are shown that the first three integral modes and displacement response peak values at the top four nodes of the simplified model are well consistent with the original model.The simplified model after eliminating subordinate dynamic degrees of freedom in the original model by the static condensation technique is effective and can be used to the dynamic analysis of the transmission tower.