Ultrasonic Measurement and Beamforming using Optical Sensors

该提案描述了超声波监测应用中灵敏、轻便的光学传感器的基本开发和响应量化。主要研究内容集中在提供超声应变场和光纤布拉格光栅（FBG）传感器之间的基本相互作用的全面理论和实验理解。该技术的两个潜在的开发实例提供了本研究的背景和应用背景：声纳阵列中的超声波束形成，以及结构健康监测中的声发射检测。这些区域被仔细地选择，因为它们包含在工程应用中通常遇到的超声信号的典型幅度范围（在发射声纳阵列中，位移场具有高幅度，通常为数十纳米，而在声发射应用中，位移场幅度可能低于100微微米）。信的支持，从泰勒斯水下系统（声纳系统）和空中客车英国（结构健康监测）包括帮助证明这项工作的价值。当然，超声波阵列监测的机会不仅限于声纳系统。超声阵列越来越多地使用复杂的编码序列驱动，这表明在声纳、无损检测和医学超声领域对提高测距精度和分辨率的需求不断增长。这种阵列中的轻量、非侵入式超声场监测能力的潜力提供了在这些阵列的输出处提供幅度和相位特性的绝对（针对光波长校准）测量的独特能力。这种测量有助于校准、优化波束成形算法以及在操作条件下连续监测实时变化的能力。如果成功的话，这项研究将使这两个应用领域以及相关领域发生重大变化。

The proposal describes the fundamental development and response quantification of sensitive, lightweight optical sensors for ultrasonic monitoring applications. The principal research components centre on providing a comprehensive theoretical and experimental understanding of the basic interactions between ultrasonic strain fields and optical fibre bragg grating (FBG) sensors. Two potential exploitation examples of the technology provide the background and application context for this research: ultrasonic beamforming in sonar arrays, and acoustic emission detection in structural health monitoring. These areas were carefully selected as they encompass the typical amplitude range of ultrasonic signals commonly encountered in engineering applications (in transmit sonar arrays the displacement fields are of high amplitude, often many 10's of nanometres, whereas in acoustic emission applications, the displacement field amplitudes may be lower than 100 picometres). Letters of support from THALES Underwater Systems (Sonar systems) and AIRBUS UK (Structural Health Monitoring) are included to help demonstrate the value of this work. Of course the opportunities for ultrasonic array monitoring are not confined to sonar systems. The increasing use of complex coded sequence actuation for ultrasonic arrays demonstrates a growing demand for improved ranging accuracy and resolution in sonar, non destructive testing and medical ultrasound fields. The potential for a lightweight, non-intrusive ultrasound field monitoring capability in such arrays provides a unique capability to provide absolute (calibrated against optical wavelength) measurement of the amplitude and phase characteristics at the output of these arrays. Such measurements facilitate calibration, optimisation of beamforming algorithms, and the capability to continuously monitor real-time changes under operational conditions. If successful the research will enable a step change for both areas of application in addition to related fields.