《激光超声多通道接收器在无损检测应用的最新进展.doc》由会员分享，可在线阅读，更多相关《激光超声多通道接收器在无损检测应用的最新进展.doc（6页珍藏版）》请在金锄头文库上搜索。
1、RECENT PROGRESS IN LASER ULTRASONIC MULTI-DECTECTORS RECEIVERS FOR NON DESTRUCTING EVALUATIONA. Wartelle1, B.Pouet1, S.Breugnot1 ,Bai Xiaobao21Bossa Nova Technologies, 2Matrix U/E technology Inc.ABSTRACT. New laser interferometric schemes were recently introduced in order to fully take advantage of
2、possibilities offered by laser-based ultrasonic (LBU) inspection and to broaden their integration into industrial inspection systems and laboratories setups. First, we will present the recent advances on a fiberized LBU receiver optimized for industrial applications. We will show an example of resul
3、ts with thickness monitoring on moving sample using zero group velocity Lamb wave resonance. Secondly, we will present the latest progress in a LBU laboratory receiver, with the development of an adaptive interferometer able to measure simultaneously both in-plane and out-of-plane displacements. Adv
4、antages of this receiver for the study of ultrasound propagation will be demonstrated with mapping of in-plane and out-of-plane displacements generated by a thermoelastic laser source.Keywords: Speckle, ultrasound, quadrature, two-wave mixing, interferometer, laser.激光超声多通道接收器在无损检测应用的最新进展A. Wartelle1
5、, B.Pouet1, S.Breugnot1 ,白小宝21Bossa Nova Technologies, 2矩阵科技有限公司摘要： 该激光干涉技术充分利用了激光超声检测(LBU)的优越性，将其应用到工业检测系统和实验室研究。首先介绍了为工业应用而优化的光纤激光超声接收器的进展，将演示一个使用群速度为零的兰姆波检测移动工件厚度的例子。然后介绍了LBU实验室级接收器的最新进展，最新研发的自适应干涉仪能同时测量面内和面外的位移，通过绘制一个由热弹性激光源所产生的面内和面外的位移来说明这种接收器在超声传播方面的应用。 关键词：光斑，超声，正交，二波混频，干涉仪，激光1 INTRODUCTION L
6、aser-based ultrasonic (LBU) is now becoming a more mature technology, making the transition from research laboratory equipment to industrial on-line measurement system. However, among the various optical techniques available, only few have been successfully implemented in industrial environment. To
7、date, LBU industrial inspection systems are still mostly based on the confocal Fabry-Prot interferometer 1, 2. The main well-known advantages of LBU are its ability to perform remote / non-contact measurements, as well as its point-like and broadband detection. New type of interferometric receiver,
8、based on the use of multi-channel detection, specifically designed for measurements in laboratories or industrial environments were recently introduced 3, 4. A first receiver, for industrial application, is based on multi-channel random-quadrature interferometer 5 and a second one, for high sensitiv
9、ity laboratory measurements, is based on a two components two-wave mixing interferometer 6. We shortly describe here the design and principle of operation of both interferometers, their improvements being based on detectors array combined with parallel processing. 2 RECEIVER FOR THE INDUSTRY2.1 Mult
10、i Channel Random-quadrature interferometer (QUARTET) This interferometer is based on a variation of the quadrature interferometer, using multi-element detectors instead of two single-element ones 3. Replacing the single-element detectors by multi-element detectors allows collecting more light (more
11、speckles) and thus increases the interferometer sensitivity by also taking advantages of the random nature of speckles. A 25x2 channel random quadrature interferometer, such as the Quartet 5, is then equivalent to 50 simple quadrature interferometers working in parallel. Initial developments were ba
12、sed on a free space setup, but for industrial application a fiberized architecture is more desirable. 2.2 Compact fiberized architecture The use of a fiberized detection head can be very advantageous for inspection of hard to reach area. The multi-channel random-quadrature interferometer described 3
13、,7 is well suited for the design of a compact and light weight fiberized interferometer. The corresponding optical setup is shown in Figure 1-A. In this fiberized setup, we take advantage of the partial reflection at the fiber end for further simplifying the optical setup. Indeed, the partial reflec
14、tion at the fiber end is used for generating the reference beam needed for interferences. The multimode fiber is used to deliver the laser beam onto the workpiece, to collect the scattered object beam and to combine the reference beam and object beam for generating the optical interferences signal.
15、The laser light is coupled into the multi-mode fiber after reflection by the polarizing beam splitter (PBS) and focused by the Lens L1. The laser beam, exiting the fiber end, is focused by L2 onto the sample surface and the scattered object beam is then focused back into the multi-mode fiber. A frac
16、tion of the laser beam is also back reflected by the partially reflective fiber end, generating the reference beam. The reference beam and the object beam are combined together during the back propagation in the multi-mode optical fiber. The optical interference exiting back the optical fiber is then focused onto the array of detectors. The signals are then processed by the parallel processing circuitry described in Referenc
