相位谱线性重构法去除Lamb波频散研究

Lamb波广泛应用于板壳结构的损伤检测,而Lamb波的频散效应使得板结构中损伤散射信号的渡越时间信息难以准确提取,因而影响了阵列波束成形损伤成像算法对损伤成像定位的效果和精度.提出的相位谱线性重构法,在中心频率处通过对相位谱展开,进行线性化处理,有效地去除了激励信号中的频散效应.该方法保证了中心频率下的信号分量不变,为研究阵列波束成形损伤成像算法对损伤精确成像奠定了基础.采用数值模拟和实验手段,验证所提出的相位谱线性重构法去除频散的效果,进而结合阵列波束成形损伤成像方法分析损伤成像定位的效果和精度.结果 表明,采用的频散去除方法能够提高损伤散射信号的信噪比,提升阵列波束成形损伤成像方法对损伤成像定位的效果和精度.

The research of Lamb wave dispersion removal by linear reconstruction of phase spectrum

Lamb wave is widely used for damage detection in plate and shell structures, but the dispersion of Lamb wave makes it difficult to accurately extract the time-of-flight information of the damage scattering signals in a plate structure, that affects the array beamforming damage imaging algorithm for damage imaging effect and precision.Linear reconstruction of phase spectrum is proposed, by expanding the phase spectrum at the center frequency and then linearizing it, which can effectively remove the dispersion in the excitation signal.This method guarantees that the signal components at the center frequency do not change, which lays the foundation for the research of array beamforming damage imaging algorithm for accurate damage imaging.Numerical simulation and experiment methods were used to verify the effect of the proposed linear reconstruction of phase spectrum method to remove the dispersion, further combined with the array beamforming damage imaging method to analyze the effect and accuracy of damage imaging location.The result shows that the adopted dispersion removal method can improve the signal-to-noise ratio of the scattered signals, and improve the result and accuracy of the array beamforming damage imaging method on the location of damage imaging.