移动荷载作用下梁裂缝识别的小波方法研究

利用小波分析对简支梁的裂缝进行识别。通过对带裂缝简支梁在移动荷载作用下的跨中响应用Mexicanhat小波进行连续小波变换，从小波系数的模极大值点有效地得到荷载经过裂缝的时间，从而识别裂缝位置，从模极大值处的Lipschitz指数判断裂缝深度，Lipschitz指数随裂缝深度的增加而减小。同时讨论了荷载移动速度和裂缝位置对Lipschitz指数的影响。通过分析和仿真计算获得满意结果，在梁结构损伤诊断中具有较高的应用价值。

Identification of Simple-Supported Beam Cracks by Means of Wavelet Analysis

A wavelet_based approach is proposed for crack identification in beam structure.The displacement at the midpoint of a cracked simple_supported beam under mobile force is analyzed with the continuous wavelet transform by using a Mexican hat fundamental wavelet.The time when the load moves through a crack is determined by the modulus maximum of wavelet coefficients.So the location of the crack can be detected.It is also addressed that the magnitude of the Lipschitz exponent can be used as a useful indicator of the damgae extent.The Lipschitz exponent decreases with the increase of crack depth.The influence of the velocity of moving load and the crack location on the Lipschitz exponent is also discussed.The validity of the proposed method is investigated by both analysis and simulations.The method presented here may be useful in damage detection for beam structures.