基于简化模型的超高层结构传感器优化布置

对于自由度较多的超高层结构,传感器优化布置时应考虑多阶模态振型.由于存在空间耦合振动,根据振型质量参与系数难以准确选择出结构弱轴方向的高阶振型.基于等效刚度参数识别法,本文提出了一种将有限元模型沿弱轴方向先简化为等效串联多自由度体系,然后根据简化结构的物理参数来计算弱轴方向振型矩阵的方法,有效地解决了这一问题.以某超高层结构为例,根据计算得到的系统振型矩阵,首先由其转置的列主元QR分解得到传感器的初始布置方案,然后以模态置信度(MAC)矩阵的最大非对角元为目标函数,采用逐步累积算法逐步增加可降低此初始布置MAC非对角元的结构自由度,并考虑经济性因素,最终确定出了传感器的布置方案.

Optimal sensor placement for super high-rise building based on simplified finite element model

The problem of sensor placement for a super high-rise building is discussed.Since the number of degree-of-freedom(DOF) of structure is large,multi-modes should be selected to describe the dynamic behavior of a structural system with sufficient accuracy to allow its health state to be determined effectively.A fundamental problem in analysis is how to accurately select the high-order modes.For this,a novel method computing the mode shape matrix of weak axis by simplified series multidegree-of-freedom system is developed based on the equivalent rigidity parameter identification method.The initial sensor assignment is obtained by the QR-factorization of the transpose of structural mode shape matrix.Taking the maximum off-diagonal element of the modal assurance criterion(MAC) matrix as a target function,adds one more sensor each time until the maximum off-diagonal element of MAC reaches the threshold.Considering the economic factor,the final plan of sensor placement of the building is determined.