透波材料脱粘缺陷微波开口探头检测法的算法及实验研究

Radome materials are used to protect radar systems on aerospace and aeronautic aircraft under severe environment. However, the existence of delamination in them seriously degrades their performances and service life. Microwave NDT method by open-ended probes has found its application in detecting delamination of radome materials, due to its merits of non-contact measurement, high penetrability, and high accuracy. For delamination detection of multi-layer radome materials by microwave open-ended probes, some problems still remain to be solved. The calculation of the reflection coefficient may encounter low convergence rate or even overflow error, due to singularities that are close to the integration path if the terminating materials are low-loss. Also, the commonly used single-frequency and single-parameter measurement method renders low accuracy and reliability. This project will be focused on highly efficient algorithm for reflection coefficient calculation for radome materials terminated, by employing contour integral technique to avoid low convergence rate or overflow error caused by singularities. An algorithm and an experimental technique for selecting multiple operating frequencies and stand-off distances, will be put forward to resolve the problems of locally optimal solutions and low accuracy for measurement. A multi-frequency and multi-parameter quantitative testing method will be established to enhance the testing accuracy and reliability, based on the multi-frequency measurement method and the algorithm which enables simultaneous determination of both electromagnetic and geometric parameters. This project is expected to provide a testing method of high efficiency and accuracy for delamination detection of radome materials. The project is hopeful to offer novel research thought and developing direction for experimental mechanics as well.

透波材料是用于保护航空航天飞行器的雷达系统在恶劣的环境下进行正常工作的介质结构。然而，脱粘缺陷的存在严重影响了其服役性能和使用寿命。微波开口探头检测法由于具有非接触、穿透性强和精度高等优点，在透波材料脱粘缺陷检测中具有独特的优势。目前，针对多层透波材料脱粘缺陷的检测仍然存在计算收敛困难和溢出等难题，且目前常用的单点频及单参数测量的方法具有精度不佳和可信度低等缺点。本项目将着重研究透波材料负载反射系数的高效算法，利用围道积分技术解决由于奇点导致的计算收敛困难和溢出的难题；建立多点频及提离距离的择优方案与实验技术，解决目前单点频率择优方案为局部最优解和检测精度不佳的问题；建立多点频、多参数定量化脱粘检测方法，利用多点频检测方法、电磁参数与几何参数同时测量的算法提高检测的精度和可信度。本项目有望为透波材料脱粘缺陷的检测提供一种高效率、高精度的实验手段，同时也为实验力学提供新的研究思路和发展方向。

透波材料是用于保护航空航天飞行器的雷达系统在恶劣的环境下进行正常工作的介质结构。然而，脱粘缺陷的存在严重影响了其服役性能和使用寿命。本项目针对低损耗透波材料脱粘检测的等效导纳法在计算过程中积分路径存在奇点、计算收敛困难的问题，提出了高效的复数域积分算法，并与传统算法和有限元软件进行对比验证了算法的高效性；采用同轴探头法对蜂窝夹层结构液体侵入缺陷进行检测，研究了水、乙醇和润滑油不同侵入液体对液体信号的影响，给出液体种类识别的方法，并提出了能对侵入区域的大小进行定量检测的特征峰方法；针对介电材料的紧贴型脱粘缺陷，提出了等相截频法，实现了微米量级厚度紧贴型缺陷的检测及定量评估，为多层介电结构内部起始脱粘缺陷的早期检测提供了一种可行的检测方法；基于小反射理论提出了双频段、多频段天线罩结构的设计方法，设计并制备了双频段、多频段复合材料夹层透波结构，并在常温下对其透波性能进行测试，验证所提出的设计方法的有效性，并利用提出的双频、多频段天线罩结构设计方法设计了高温天线罩，采用石英材料制备了高温双频结构，并进行了高温实验测试和验证。本项目有望为透波材料脱粘缺陷的检测提供一种高效率、高精度的实验手段，同时也为实验力学提供新的研究思路和发展方向。