基于POD法控制模态选择的大跨屋盖结构风致动力响应分析

Wind-induced dynamic response analysis of long-span roof structure based on selection of dominant vibration-modes with POD method

为了提高大跨度屋盖结构风致动力响应频域分析的计算效率,提出先挑选控制模态再进行风致响应有效计算的"二步法"过程.将本征正交分解(POD)法和模态叠加法相结合,建立风荷载作用下大跨屋盖结构各阶模态响应的快速估算方法,并以估算结果作为衡量准则进行控制模态的挑选;在经过挑选得到控制模态后,采用考虑了荷载空间分布相关性和广义风荷载谱中虚部成分的精确完全二次项组合方法(ACQC)进行风致响应的有效计算.将该方法运用于某大型火车站站台屋盖结构,计算表明:在采用相同的模态参与阶数的条件下,本方法得到的风致响应结果具有更高的精确性和更快的收敛性.

In order to increase the computational efficiency of the wind-induced dynamic response analysis of long-span roof structures with the frequency-domain method, a two-step method, which means firstly modes selecting then effective wind-induced response calculation, was proposed. The way of quick estima- ting each modal response of the long-span roof structure under the wind loads was introduced by the com- bination of the proper orthogonal decomposition（POD）method and the mode superposition method, and the estimative results were used as a measure of the criteria for the control mode selection. After the selec- tion of control mode, the wind-induced responses were calculated effectively by accurate complete quadratic combination（ACQC） method, which had taken into account the partial correlation of wind loads and the imaginary parts of the generalized wind forces. The method was applied in some large railway station plat- form, and the results indicated that, with the same number of the contribution modes, the wind-induced responds obtained by the proposed method had high accuracy and fast convergence.