Research On Fiber Composite Materials And Embedded Encapsulation Technology Based On Bragg Gratting

Fiber Bragg grating have been widely used due to their small size,high precision,corrosion resistance,and anti-electromagnetic interference characteristics.However,the bare grating is extremely fragile and easy to break,and it needs to be packaged and protected when working in harsh environments.After investigation,most grating sensors are mainly packaged with a single fiber or metal material.Such packaged grating sensors are prone to different degrees of damage such as creep or corrosion.Therefore,it is necessary to explore a grating package structure that can adapt to extremely complex environments.In order to overcome these shortcomings,this article will carry out research from two aspects,one is to use composite materials to make the sensor package substrate,and the other is to combine magnetron sputtering and laser welding technology to make an embedded grating package structure.Firstly,the research background and significance of the subject are introduced,the domestic and foreign FBG packaging methods are investigated,the working principle of FBG is explained,and the packaging methods of gratings are classified and summarized.Secondly,the method of encapsulating grating sensors with composite material substrates was explored,four packaging substrates with different structures were designed,and temperature and stress experiments were carried out to test their performance.Simulation experiments were carried out to simulate the stress distribution of each structure during deformation,and analyzed reliability of these structures,the performance of the package structures were evaluated from two perspectives of hysteresis error and repeatability error.Thirdly,combined with magnetron sputtering technology and laser welding technology,a built-in capillary copper tube packaged fiber grating was fabricated.Theoretical analysis and simulation experiment verified its stress-sensitivity characteristics under specific condition,and carried out temperature and Stress experiments test its performance,combined with sensitivity,fitting and repeatability to comprehensively evaluate the performance of the embedded package structures.Finally,the traditional strain gauge stress monitoring system and the fiber grating stress demodulation system are compared,and an experimental system with two stress monitoring technologies is built.By comparing the errors between stress values detected by two methods and theoretical values,it is show superior performance of the fiber grating stress monitoring system.