基于动力响应互相关的古建筑木结构损伤识别

Damage Identification of Ancient Timber Structure Based on Cross-Correlation of Dynamic Response

提出了基于互相关系数和互相关峰值变化率的古建筑木结构损伤识别和定位方法。以随机振动结构的某一测点为参考点,计算其他各测点与参考点的加速度响应之间的互相关函数,将所有的最大值组成互相关峰值向量(Cross-Correlation Peak Vector,CCPV)。以两组CCPV之间的互相关系数作为损伤因子对结构进行损伤识别,以结构损伤前后互相关峰值的变化率作为损伤识别指标,对结构进行损伤定位。以西安钟楼为工程背景,建立一榀木框架有限元模型进行分析。结果表明:结构损伤后,损伤因子的数值明显降低,可以有效识别结构的损伤;结构损伤前后峰值变化率最大的相邻两个测点对应着损伤单元的两个节点,可以准确确定结构的损伤位置,同时可以根据损伤因子和峰值变化率的变化范围估计结构的损伤程度。

A method for damage identification and location of ancient timber structure based on cross-correlation coefficient and cross-correlation peak change rate is proposed.Taking a measurement point of random vibration structure as a reference point,the cross-correlation function between acceleration responses of other measurement points and the reference point is calculated,and all the maximum values are formed into cross-correlation peak vector(CCPV).The cross-correlation coefficient between two CCPVs is used as the damage factor to identify the structure,and the change rate of the cross-correlation peak before and after the structure damage is used as the damage identification index to locate the damage.Taking Xi’an Bell Tower as the engineering background,a finite element model of a wooden frame was established for analysis.The results show that the value of damage factor is significantly reduced after structural damage,which can effectively identify structural damage.The two adjacent measuring points with the highest peak change rate,which determines the damaged location of the structure,correspond to the two nodes of the damaged unit.At the same time,the damage degree of the structure can be estimated according to the change range of the damage factor and the peak change rate.