摘要
结构损伤是一种非线性发展过程,会导致结构模态参数的变化,因此可以通过时变模态振型特征识别损伤状况。对结构的响应信号进行小波变换,提取当小波系数模出现局部极大值时的尺度参数,利用这些尺度参数识别结构的瞬时频率。选取特定尺度参数,对结构各个节点的信号进行小波变换,将信号解耦到只含某一阶模态,通过小波系数的比值进行归一化处理,从而得到结构的瞬时振型。对结构瞬时振型差做小尺度的小波变换,通过小波系数的实部出现极大值的时间及其出现的位置识别出结构的损伤时间与损伤位置,通过极大值的大小判断损伤程度。应用一个悬臂梁和斜拉桥数值算例,证明该方法不仅能准确识别结构发生损伤的时间,而且能高精度、高效率地识别结构损伤位置和损伤程度。
Structural damage leads to the change of structural modal parameters,so the damage status can be identified by time-varying modal mode shape.First,by wavelet transformation of response signals,wavelet scale parameters were extracted according to the local maximum value of wavelet coefficients modulus.The instantaneous frequency of a time-varying structure was estimated from the wavelet scale parameter.Afterwards,a specific scale was selected and the signal of each node of the structure was decoupled into a single mode by wavelet transformation with the specific scale parameter,and the instantaneous mode shape of the structure was obtained by normalizing the ratio of the wavelet coefficients.Finally,the wavelet transformation was applied to the variance of mode shape on a small scale.The existence time and position of damage were identified by the local maximum value of the real part of the wavelet coefficients.The damage extent was identified by the maximum value of the real part of wavelet coefficients.The proposed method was applied to a cantilever beam and a cable-stayed bridge.It was approved that the wavelet transformation on the time-varying modal mode shape method can not only identify the existence time of damage,but also identify the damage position and damage extent of structures with high accuracy and efficiency.
作者
王盟
翁顺
余兴胜
闫俊锋
殷鹏程
WANG Meng;WENG Shun;YU Xingsheng;YAN Junfeng;YIN Pengcheng(School of Civil Engineering and Mechanics,Huazhong University of Science and Technology,Wuhan 430074,China;Hubei Key Laboratory of Control Structure,Huazhong University of Science and Technology,Wuhan 430074,China;China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan 430063,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2021年第16期10-19,共10页
Journal of Vibration and Shock
基金
国家自然科学基金(51778258,51922046,51629801)
中铁第四勘察设计院集团有限公司科研项目(2018D001)
中交第二公路工程局有限公司科研项目(KJFZ-2019-029)
中铁二院工程集团有限责任公司科研项目(KYY2019029(19-21))。
关键词
模态振型
损伤状况
小波变换
尺度参数
modal mode shape
damage condition
wavelet transformation
scale parameter
