一种新的小波及其在结构损伤检测中的应用

结构受冲击将引起某些部位的震荡、裂纹甚至断裂,从而导致结构刚度下降.此时振动信号会出现奇异性或携带突变信息,而这些突变信息反映了结构的损伤情况.加之冲击信号测试环境一般较为复杂,环境噪声对测试存在一定的影响.然而,利用合理的小波变换技术去噪可以识别出损伤情况.本文通过对冲击振动的信号特性进行分析构造了一种新的基本小波,并论证了该小波的基本特征.最后运用小波分析的信号奇异检测理论结合实例将该小波用于冲击振动仿真分析中.计算结果表明,利用该小波进行结构损伤信号分析能清晰地识别结构损伤的时刻.采用该小波函数的构造方法,可避免通常采用Daubechies系列小波作为信号分析而要繁琐地选择不同小波函数的过程.

A New Wavelet and Its Application to Damage Detection of Structure

There may occur oscillation,cracking and even rupture in engineering structure under compact loading,which lead to reduction of the stiffness of structure.During impact process,the oscillation signals can appear singularity or carry some breaking information.The induced abrupt change information reflects the damage situation of structure.In addition,due to the complexity of environment of shocking signal measurement,some resulting noises can affect signal records.However,using a reasonable wavelet transform technique,the noises can be eliminated and structure damage can be detected under such condition.Based on the characteristics of analysis of signals,a new sort of basic wavelet function,which satisfies the basic condition of wavelet was constructed.This wavelet and its effectivences in damage detection were discussed and demonstrated by a numerical simulation.The exact time of structure damage was determined by means of the corresponding singularity detection theory on wavelet analysis.The utilization of present proposed method for constructing the wavelet function can avoid tedious process in the choice of different wavelet functions of Daubechies serises commonly used to signal analysis.