CAJ | 학술논문

传统的兰姆波多采用压电陶瓷换能器激发和接收.建立了新的超声兰姆波无损检测系统,其基本思想是采用布拉格光纤传感器作为兰姆波的接收器.光纤光栅传感的基本原理是通过检测光栅反射的中心波长移动实现对外界参量如超声的测量.超声作用下光纤光栅的反射谱发生变化,对超声作用下光纤光栅的反射谱变化进行了数值分析,结果表明,超声对光栅反射谱的影响与超声波长与光栅长度的比值是高度相关的.只有当这个比值相当大时,反射谱的形状才不会变化而中心波长发生偏移,此时光纤传感器可用来探测兰姆波.这个结论为利用新的兰姆波无损检测系统在布拉格光栅长度的设计和兰姆波波长的选择方面提供了有用的工具.
전통적란모파다채용압전도자환능기격발화접수.건립료신적초성란모파무손검측계통,기기본사상시채용포랍격광섬전감기작위란모파적접수기.광섬광책전감적기본원리시통과검측광책반사적중심파장이동실현대외계삼량여초성적측량.초성작용하광섬광책적반사보발생변화,대초성작용하광섬광책적반사보변화진행료수치분석,결과표명,초성대광책반사보적영향여초성파장여광책장도적비치시고도상관적.지유당저개비치상당대시,반사보적형상재불회변화이중심파장발생편이,차시광섬전감기가용래탐측란모파.저개결론위이용신적란모파무손검측계통재포랍격광책장도적설계화란모파파장적선택방면제공료유용적공구.
Piezoceramic transducers have been the most commonly used method for generating and receiving Lamb waves traditionally. A new ultrasonic Lamb wave nondestructive testing (NDT) system is developed in this paper. The basic idea is to use a fiber Bragg grating (FBG) sensor as an acoustic receiver of ultrasonic Lamb waves generated by a piezoceramic transducer. The basic principle of FBG is to measure external force such as ultrasound field by detecting the center wavelength shift of the light reflected from the grating. The reflection spectrum changing of a FBG due to the interations with an ultrasound wave has been numerically analyzed. The results show that the influence of ultrasonic field on grating spectrum is highly correlated to the ratio between the ultrasonic wavelength and the grating length. Only when the ratio is quite larger, the center wavelength of reflection spectrum shifts while the shape of the grating remains unchanged, which provide useful tools for the design of gage length of FBG sensor and the choice of Lamb wave wa-velength when the new NDT system is used for Lamb wave detection.