基于光纤光栅的旋转机械扭振传感机理和方法研究

Torsional vibration measurement has great significance in rotating machinery condition monitoring and fault diagnosis and is directly related to the development of the national economy and national defense construction. However the existing measurement methods subject to the limitation of inconvenience of installation, signal transmission problems and poor anti-interference ability. Fiber Bragg grating (FBG) with the characteristics of small size, light weight, resistance to electromagnetic interference, linking many sensors into sensing network using various multiplexing technology, realizing multi-point monitoring to achieve its properties can break the limitations of traditional torsional vibration sensing technology. However, the problems in structural design of FBG torsional vibration sensor, fiber grating strain transfer mechanism and signal feature extraction propose new theoretical challenges to its application. This project intends to study the fiber grating torsional vibration sensing composite structure by analyzing the dynamic characteristic of rotating machinery torsional vibration, establish its strain transfer model, carry out the testing and validation experiments of fiber gratings torsional vibration sensor, get torsional vibration signature of FBG sensing, propose design theory and method of FBG torsional vibration sensor. The anticipated results of this project can solve the problems of traditional electrical measuring methods in circuit complexity, signal transmission and anti-electromagnetic interference, enrich and develop the modern testing theory and online monitoring technology for rotating machinery and provide the theoretical basis for the application of FBG torsional vibration sensor.

扭振测量对旋转机械的运行状态监测和故障诊断具有重要意义，直接关系到国民经济的发展和国防建设。但现有测量方法存在安装不便、信号传输困难、抗干扰能力差等问题。光纤光栅具有体积小、重量轻、抗电磁干扰强及一线多点、无源多场的特点，可突破传统扭振传感实时性和分布式检测的局限。然而，光纤光栅扭振传感的结构设计、应变传递机理、信号特征提取等问题亟待解决，给其应用提出了新的理论难题。为此，本项目拟研究基于光纤光栅的旋转机械扭振传感机理和方法，通过分析旋转机械扭振的动力学特性，研究光纤光栅扭振传感体复合结构，建立其应变传递模型，开展光纤光栅扭振传感器的测试分析和验证实验，获取光纤光栅传感的扭振特征信号，提出基于光纤光栅的扭振传感器设计理论与方法，解决传统电测方法线路复杂、信号传输困难以及抗电磁干扰能力差的难题，丰富和发展现代测试理论和旋转机械在线监控技术，为光纤光栅扭振传感器的应用奠定理论基础。

当前旋转机械在社会生产和人民生活中应用越来越广泛，并朝着大型化、高速、重载、大功率方向发展，其轴系结构越来越复杂，从而导致网机耦合，诱发轴系扭振，并造成扭转疲劳，严重时甚至导致部件的瞬时破坏，故旋转机械扭转振动问题日趋严重，已成为引起旋转机械故障的重要原因之一。扭振检测对于旋转机械运行状态评估具有重要意义，而现有的扭振测量技术在传感器安装的方便性，信号的传输与处理，抗干扰等方面还存在问题。因此，深入研究旋转机械扭振测量方法、改善监测装置性能、开发和完善扭振测试系统，已成为旋转机械状态监测和故障诊断领域的迫切任务。 .本项目首先在剖析旋转机械扭振现象的基础上，建立了旋转机械扭振动力学模型，提出了两种基于光纤光栅的旋转机械扭振测量方法，解决传统电测方法线路复杂、信号传输困难以及抗电磁干扰能力差的难题。然后对两种光纤光栅扭振传感器进行了扭振传感特性实验分析，并根据旋转机械光纤光栅扭振测试特点，提出了旋转机械光纤光栅扭振检测集成系统设计方案，设计了旋转机械扭振检测试验平台，开发了集成测试系统软件平台，实现了光纤光栅以及电测数据的采集、传输、储存以及分析和处理。最后开展了光纤光栅扭振检测方法实验测试，完成了两种接触式扭振传感器在不同加载条件下的扭振响应测试，通过对信号进行希尔伯特变换的包络谱分析和小波变换时频谱分析，提取扭振激励信号特征量；通过对运行全过程数据时频分析，有效获取了扭振发生时间及激励源特征信息，为旋转机械运行状态安全性的判断提供依据。