【摘要】 为实现在钢轨中激励特定模态的导波,采用半解析有限元(Semi-Analysis Finite Element,SAFE)方法建立钢轨的SAFE模型,推导沿钢轨传播导波的控制方程,计算导波在钢轨中传播的相速度和群速度;根据导波在钢轨中传播的相速度频散曲线确定梳状传感器的工作点,设计能够在钢轨中激励特定模态导波的梳状传感器。将设计的梳状传感器布置在5.5m长的60kg·m-1钢轨上,根据实测钢轨的回波信号端面波包计算的32和64kHz导波群速度分别为2 583和2 750m·s-1,与利用钢轨SAFE模型计算所得的理论群速度2 626和2 734m·s-1相比,分别只相差1.64%和0.59%,说明建立的钢轨SAFE模型计算精度高,设计的梳状传感器能够实现特定模态导波的激励。更多还原

【Abstract】 In order to excite a particular mode guided wave in rail,the Semi-Analysis Finite Element（SAFE）method is adopted to build the SAFE model for rail.The governing equation of guided wave propagating in rail is established.The phase velocity and group velocity of guided wave in rail are calculated.The working point of comb transducer is determined based on the phase velocity dispersion curves,and the comb transducer for exciting aparticular mode guided wave is designed.The designed comb transducer is fixed in a 5.5mlong 60kg·m^-1 rail.The group velocities of 32 and 64kHz guided waves are calculated from the measured the end wave packet of echo signals,which are 2 583 and 2 750m·s^-1 respectively,and are compared with the theoretical results of 2 626 and 2 734m·s^-1 calculated by SAFE model.The differences are only 1.64%and 0.59%respectively,which illustrates the accuracy of SAFE model and the feasibility of the particular mode guided wave excitation by comb transducer.更多还原