CAJ | 학술논문

为了分析超声导波信号遇到缺陷时的频谱变化,分别对铝蒙皮蜂窝板试样内传播的A0模式和S0模式导波信号进行了小波变换时频分析,研究了蜂窝板板内导波信号中各频率成分随时间的变化情况,计算了导波的实际群速度,讨论了A0模式和S0模式群速度误差的不同。研究结果表明,利用小波变换可以对铝蒙皮蜂窝板中的导波信号进行动态的频谱分析和模式识别,并可对实际的群速度进行测量,且A0模式的群速度误差较小。
위료분석초성도파신호우도결함시적빈보변화,분별대려몽피봉와판시양내전파적A0모식화S0모식도파신호진행료소파변환시빈분석,연구료봉와판판내도파신호중각빈솔성분수시간적변화정황,계산료도파적실제군속도,토론료A0모식화S0모식군속도오차적불동。연구결과표명,이용소파변환가이대려몽피봉와판중적도파신호진행동태적빈보분석화모식식별,병가대실제적군속도진행측량,차A0모식적군속도오차교소。
In order to study frequency spectrum variation of ultrasonic guided waves when the defects were existed,the wavelet time-frequency spectrum analysis were applied to the signal interpretation of A0 mode and S0 mode guided waves propagating in Aluminum-skin honeycomb core sandwich structure.After studying of the frequencies variation of the signal propagated in sandwich structure,the real group velocity of A0 mode and S0 mode were calculated and their errors were discussed.The results show that the wavelet transform method can be applied to not only the frequency spectrum analysis and mode identification of guided waves but also an accurate measurement of their group velocity.The group velocity error of A0 mode is less than S0 mode.