光纤光栅啁啾效应及不同温度场管结构状态监测技术研究

发布时间：2019-05-28 03:43

【摘要】：航空航天结构通常工作在热、力、磁等多物理场耦合复杂环境,极端温度环境下结构易发生变形,力学性能也有所减弱,从而使结构存在安全隐患,因此开展针对结构状态的监测研究具有重要意义。光纤光栅能够感测材料温度、应变等70余种物理量且体积小、灵敏度高、抗电磁干扰、易构建分布式传感网络等优越性能。因此,本文研究了基于光纤传感技术的管状结构热应变及变形监测方法,主要内容包括以下几个方面:首先,针对航空结构的温度场监测需求,对复杂环境温度场下光纤光栅易产生的啁啾效应的原因进行研究。利用光学软件Optigrating对非均匀场作用下光栅反射光谱进行模拟。在此基础上,搭建光纤光栅非均匀温度场及应变场试验系统,根据数值仿真和试验结果,得到光纤光栅啁啾现象产生机理和影响特性。其次,研究不同形式与胶接条件下的光纤光栅传感器在高低温温度场中传感特性,给出光纤光栅低温下易产生啁啾效应原因。在此基础上,通过设计合理的传感器封装减弱光纤光栅低温啁啾效应。再次,构建了基于分布式光纤光栅传感网络的铝合金以及碳纤维复合材料管状结构均匀温度场监测系统。根据稳态均匀温度场作用下的管结构热变形理论和仿真数值,提出一种计算管状结构轴向变形的快速计算方法,并验证了该方法的可行性。最后,构建了基于分布式光纤光栅传感网络的管状结构非均匀温度场监测系统。通过分析铝合金管状结构表面温度场梯度特征,结合仿真结果,给出管状结构轴向变形计算方法,并得到管状结构表面光纤光栅所受非均匀温度场下反射光谱特性。
[Abstract]:The aerospace structure usually works in the complex environment of thermal, force, magnetic and other physical field coupling. The structure is prone to deformation and the mechanical properties are weakened in the extreme temperature environment, which makes the structure have hidden dangers of safety. Therefore, it is of great significance to carry out the monitoring research for the structural state. Fiber grating can sense more than 70 kinds of physical quantities, such as material temperature and strain, and has the advantages of small volume, high sensitivity, anti-electromagnetic interference, easy to construct distributed sensor network and so on. Therefore, the thermal strain and deformation monitoring method of tubular structure based on optical fiber sensing technology is studied in this paper. the main contents include the following aspects: first, according to the temperature field monitoring requirements of aeronautical structure, The causes of chirp effect of fiber gratings in complex ambient temperature field are studied. The reflection spectrum of grating under the action of non-uniform field is simulated by optical software Optigrating. On this basis, the non-uniform temperature field and strain field test system of fiber gratings is built. According to the numerical simulation and experimental results, the mechanism and influence characteristics of chirp phenomenon of fiber gratings are obtained. Secondly, the sensing characteristics of fiber grating sensors in high and low temperature fields under different forms and bonding conditions are studied, and the reasons for chirp effect of fiber gratings at low temperature are given. On this basis, the low temperature chirp effect of fiber gratings is weakened by reasonable sensor packaging. Thirdly, the uniform temperature field monitoring system of aluminum alloy and carbon fiber composite tubular structure based on distributed fiber grating sensor network is constructed. According to the thermal deformation theory and simulation value of pipe structure under the action of steady uniform temperature field, a fast calculation method for axial deformation of tubular structure is proposed, and the feasibility of this method is verified. Finally, a tube structure non-uniform temperature field monitoring system based on distributed fiber grating sensor network is constructed. Based on the analysis of the gradient characteristics of the surface temperature field of the tubular structure of aluminum alloy, combined with the simulation results, the calculation method of the axial deformation of the tubular structure is given, and the reflection spectral characteristics of the fiber grating on the surface of the tubular structure under the non-uniform temperature field are obtained.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：V414;V214;TP212

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