基于相干激光多普勒测振原理的复合材料无损检测能力评价及误差校正方法研究

The use of the Laser Doppler Vibrometry (LDV) in damage detection of the composite material is a potential non-destructive testing (NDT), as it offers high-sensitivity high-resolution non-contact and broad-band measurement capability. But unfortunately, the performance evaluation and the results calibration of the NDT based on the LDV need much more improvement. Thus, the project will begin from the physical mechanism and analyze the influence between the LDV and the detecting environment with the NDT results by means of LDV. Then describe the relationship between the LDV and the environment parameters with the sensitivity, the resolution and the error in order to derive the evaluation criterion and the calibration methods for the NDT based on LDV. Moreover, together with the rebuilding LDV and the ultrasonic flaw detector using pulse echo technique, finishing the results calibration experiments of the NDT based on LDV. Finally, regarding to its applicability and capability, evaluating the calibration criterion mentioned above according to the experiment results. The researches object to give a method of removing the effect of the LDV and the environment. In addition, the project will also provide a technical support for developing the high performance NDT with own intellectual property for our country.

基于相干激光多普勒测振原理的复合材料无损检测既可实现远距离、非接触、实时原位的检测模式，又能发挥相干激光的优势进而保证高灵敏、宽频带的缺陷损伤判定。但基于相干激光多普勒测振原理的复合材料无损检测能力评价及误差校正方法研究尚需完善。为此，本项目从物理机制入手，通过数值模拟激光多普勒测振系统、检测环境干扰对该无损检测方法的影响，分析测振系统参数和环境干扰特征参量与检测灵敏度、分辨率及检测误差之间的关系，定量得出该无损检测方法检测能力的评价方法及误差校正方法。利用改造的激光多普勒测振系统和脉冲反射式超声波探伤仪等无损检测设备联合同步测量，完成误差校正方法实验。最后根据实验数据评价该无损检测方法及其误差校正方法的能力和适用性，以解决测振系统固有噪声和环境干扰对复合材料无损检测的影响这个科学和技术问题。本项目将为我国研发具有自主知识产权的高性能复合材料无损检测系统提供理论和技术支持。

根据项目的研究目标，本项目首先系统分析了激光器特性、光程、参考光和信号光能量比对激光多普勒测振系统探测性能的影响，从而确立激光多普勒测振系统的正确工作方式。在此基础上，分别以单层钢质材料和双层复合材料为研究对象开展了基于激光多普勒测振系统的复合材料无损检测方法的对比仿真研究，并标定了其无损检测能力。在实验研究方面，搭建了一套快速扫描式的激光多普勒振动测量系统，核心部件包括用于检测复合材料振动特征的激光多普勒振动测量单元和用于实时改变激光多普勒振动测量单元中探测光的照射位置的探测光跟踪扫描控制单元，并针对复合材料无损检测信号的高速采集和实时处理这一难题开展了详细的研究，最终建立了基于相干激光多普勒测振原理的复合材料无损检测评价方法。本项目的相关研究成果已经发表或投稿到相关的国内外学术期刊，对促进激光多普勒测振技术在无损检测领域的应用有积极的推动作用。