移动载荷下桥梁速度响应小波分析多裂纹识别

Multiple Damages Identification in a Beam Subjected to Moving Load by Using Wavelet Analysis and Velocity Response

讨论了利用简支梁中点的速度响应进行结构多损伤检测的可行性。首先利用有限元计算了移动载荷作用下桥梁中点的位移和速度响应信号,并比较了梁中点动态响应及小波变换对损伤的敏感性。数值研究表明,损伤对速度响应"Gaussian-5"小波分析较敏感。其次,利用此方法可以较方便地识别出损伤位置,并将小波系数局部极大值作为损伤指标(DI)来估计损伤程度。最后,讨论了不同噪声水平、载荷速度对损伤识别结果的影响,表明该方法具有较好的噪声容忍度;当提高载荷速度时,边界影响增强,不利于损伤定位。

In this paper, the investigation is focused on a new method for multiple damages detection by velocity re- sponse. Firstly, the responses of a simple beam middle point are obtained by Definite Elements Method （DEM） when it is subjected to moving load. The responses and the Continuous Wavelet Transforms （CWT） are compared on damage sensitivity, respectively. The number investigation shows that damage is more sensitive to ＂Gaussian-5＂ CWT of velocity response. Secondly, the damage location is indicated by method. The local max value of CWT coefficients at the damage location is regarded as Damage Index （DI）and it can be used to indicate the level of damage. Finally, the influence of the noise level and moving load velocity to damage detection is investigated. The results show that the method has good tolerance of noise, but high velocity of moving load is adverse to damages detection.