Lamb波驱动器的最佳激励波形选择

Optimal Excitation Waveform Selection for Lamb Wave Actuator

采用高斯窗、海明窗和汉宁窗调制正弦脉冲信号得到不同循环次数的激励波形,分别激励压电式Lamb波驱动器产生Lamb波;引入品质因数(Q)分析信号的频带和频域内强度分布,研究不同窗函数抑制Lamb波频散的效果。实验结果表明,对于相同循环次数不同窗函数调制的激励波形中,经汉宁窗调制的激励信号产生的Lamb波Q值高,频带窄;对于相同窗函数调制的激励波形,随着循环次数的增加,Q值增大。实际应用时可用汉宁窗调制并根据传播距离确定循环次数得到Lamb波最佳激励波形。

This paper has presented our research work on the optimal excitation waveform of Lamb wave.By applying Gaussian window,Hamming window and Hanning window to modulate the sinusoid pulse signals and the excitation waveforms with different cycle number have been obtained and the piezoelectric Lamb wave driver has been excited to generate the Lamb waves.The quality factor Q parameter was introduced to analyze the signal band and the strength distribution in the frequency domain.The effect of the different window functions to suppress the frequency dispersion of Lamb wave has been studied.The results indicate that when the excitation waveforms obtained by different modulated signal have equal cycle number,the waveform which is modulated by Hanning window has highest Q and narrowest bandwidth.When the excitation waveforms obtained by same window modulating,the Q value increases with cycle number increasing.In practical applications,the optimal Lamb excitation waveform can be obtained by using the Hanning window modulating and by determining the appropriate cycle numbers according to the propagation distance.