Smart Metal Structure With Surface Mounted In-fiber Bragg Grating By Using Soldering Method

Fiber bragg grating(FBG) has been widely used in air plane, optical communication, construction structure and etc. over the last few years, for its characteristics of high sensitivity, anti-electromagnetic interference, resistance to corrosion, small size and light weight. In order to get smart metal components by embedding the fiber Bragg grating sensor, the smart metal structure’s stress/strain can be real-time monitorred. Thus, the security and reliability of the metal structure or system can be improved.The reasearch and application status of the fiber Bragg grating was briefly introduced in the paper; the chemical plating and electroplating metallized protection method was improved; the fiber Bragg grating central wavelength shift during the metallized protection process was studied and analyzed. Based on the study of sensing principle of the fiber Bragg grating, the temperature sensing characteristic of a metallized fiber Bragg grating was tested in a temperature controlled water basin. In order to real time measure and control the temperature and strain of the heat affected zone(HAZ) during low-carbon steel TIG welding process, temperature measurement was carried out using fiber Bragg gratings. The metallized fiber Bragg grating was soldered on the surface of a metal cantilever to sense the stress and a strain and stress transfer model was presented:the relationship between the central wavelength of the metalized fiber Bragg grating and stress/strain/applied loading was studied and analyzed, the stress transfer model was simulated by using ANSYS.The mian works are as follows:(1) The metallized protection Proeess(chemical plating and electro Plating) for the FBG was studied and improved, the fiber and FBGs with nice metal coating were acquired. With the metal coating, the FBGs have the characteristic of high temperature resistant and higher sensitivity.(2) The effects of the metal coating process on the sensing character and the wavelength shift was studied and analyzed.(3) The temperature sensing characteristic of a metallized fiber Bragg grating was tested in a temperature controlled water basin, and temperature measurement of heat affected zone using fiber Bragg grating during the TIG welding process of low-carbon steel sheet was carried out.(4) A stress transfer model of fiber smart cantilever structure was presented, tested and simulated.