CAJ | 학술논문

以LFMCW(linear frequency modulated continuous wave)时间间隔测量原理为基础,针对L_(CR)波(the critically refracted longitudinal wave)声弹性应力检测脉冲激发方式时存在的问题,提出了一种基LFMCW方式激发L_(CR)波的切向正应力检测系统,使用新的检测方法通过发射信号和接收信号形成的拍频信号来反映波的传播时间,用抛物线插值与最小二乘相结合的数字测频方法准确测量拍频频率.实验结果证明了该系统对L_(CR)波传播声时检测的有效性.
이LFMCW(linear frequency modulated continuous wave)시간간격측량원리위기출,침대L_(CR)파(the critically refracted longitudinal wave)성탄성응력검측맥충격발방식시존재적문제,제출료일충기LFMCW방식격발L_(CR)파적절향정응력검측계통,사용신적검측방법통과발사신호화접수신호형성적박빈신호래반영파적전파시간,용포물선삽치여최소이승상결합적수자측빈방법준학측량박빈빈솔.실험결과증명료해계통대L_(CR)파전파성시검측적유효성.
The pulse ultrasonic exciting approach based on the sonic elastic theory to measure the stress with the critically refracted longitudinal wave(L_(CR) wave)was inefficient.Through research on the principle of time-interval measurement with linear frequency modulated continuous wave,an optimized test system with LFMCW method to stimulate the LCR wave is introduced.The beat frequency signal produced from the waveform transformation in the propagation process can reflect the travel time with emission signals and received signals,and in contrary to the former study,they can accurately measure the frequency with a frequency measurement algorithm using parabola interpolation and least square method.The experimental results show the effectiveness of the new approach in the detection of propagation time with LCR wave.