大跨桥梁结构健康监测系统振动传感器配置仿真

Simulation study on vibration senor placement for structural health monitoring system of long-span bridge girder

为了提高大跨桥梁结构健康监测系统在线模态参数识别中的模态分辨率,研究了振动传感器配置的非均匀布设方法.以润扬长江大桥悬索桥为例,以结构前16阶竖向振型为基础,运用基于主列筛选的传感器配置算法对该桥主梁竖向振动传感器配置进行了仿真研究.采用模态置信度矩阵非对角元素构造评估指标对4种传感器布设方案进行比较,包括七截面均匀布设方案、基于主列筛选算法获得的七截面非均匀布设方案、基于七截面均匀布设方案改进得到的九截面方案和基于主列筛选算法获得的九截面非均匀布设方案.由仿真结果可知,采用主列筛选获取的传感器非均匀布设方案获得的模态置信度矩阵非对角元较小,模态振型具有更好的模态分辨率.这一结果表明,非均匀布设方法更有利于大跨桥梁监测系统实现在线识别模态参数.

Non-uniform distribution of vibration sensors is studied with the purpose of improving the mode independence in the structural health monitoring oriented online modal identification of long-span bridges.A new sensor placement method based on the principal subset selection algorithm was employed to determine the non-uniformly distributed sensor locations.Runyang Yangtse River Suspension Bridge was taken as a benchmark to evaluate the current uniformly distributed sensor locations and non-uniformly distributed ones.Mode shapes of the first sixteen vertical modes were used in the simulation.Indicators which are constructed based on the non-diagonal elements of modal assurance matrix were adopted to compare four groups of sensor distribution including uniform distribution of seven sensors,non-uniform distribution of seven sensors,uniform distribution of seven sensors with two complementary sensors and non-uniform distribution of nine sensors.Results show that non-uniform distribution of vibration sensors will assure the independence of mode shapes.Hence,it will be helpful to make the monitoring system able to automatically identify modes without human direction.