摘要
利用LS-DYNA970动态有限元分析软件对考虑横应变下的管道纵向超声导波损伤检测进行了数值模拟,分析了不同的激发频率对管道中导波频散现象的影响.选择适当的尺度和小波基函数,利用小波变换实现了对微弱且无法直接观测的缺陷检测信号的识别.同时通过时频分析研究了噪声信号在检测信号中的分布规律,并运用小波包分解和重构算法将信噪分离,实现高噪条件下管道微缺陷的损伤识别.
Using the LS-DYNA970 dynamic commercial finite element program,the numerical simulations of the transonic longitudinal guided-wave in cracked pipes are conducted, in which the effect of transverse strains has been taken into consideration. The influence of the excitation frequency on the frequency dispersion of guided waves is analyzed. By choosing proper scale and basic functions of wavelets, the weak signals of defect detection are identified, which cannot be observed directly. Meanwhile, the distribution of the noise in the detection signals is discussed by time-frequency analysis. And the crack identification in the low signal-noise ratio is realized based on the algorithm of wavelet decomposition and reconstruction.
出处
《固体力学学报》
CAS
CSCD
北大核心
2009年第4期368-375,共8页
Chinese Journal of Solid Mechanics
基金
国家自然科学基金项目(10672067)资助
关键词
管道
频散
损伤检测
小波变换
小波分解和重构
pipe, frequency dispersion, damage detection, wavelet transform, wavelet decomposition and reconstruction
