Theory Research And Method Of Fiber Bragg Grating Sensors Based On Thermal-Mechanical Coupled

As we all know, coupling problem widely exists in nature and engineering practice. As the major mechanical equipment structure systems are developing towardserialization, high speed, high efficiency, multi-functionalization, refinement andautomation, on the one hand, it brings huge social and economic benefit. At the same time, the working conditions of equipment are also more rigorous, it showsvarious physical fields coupling. How to solve the reliable monitoring to mechanicalequipment under strong coupling is also paid more attention by people. FBG sensor has advantages of small volume, light weight, good flexibility, anti-electromagneticinterference and chemical resistance etc. It is very suitable to do safety monitoring tomechanical equipment. However, existing research to FBG stress sensor is still stay incondition of single physical field effect, FBG sensor under multi-field coupling isurgently be studied.Based on the basic theory and basic experiment of FBG sensor, combined withthe finite element analysis method, from aspects of material and structure etc., thispaper discussed the design theory and method of FBG stress sensor under multi-fieldcoupling especially thermal-mechanical coupling. The following several aspects havebeen done in this paper:1. Analyzed the research status of multi-field coupling theory at home and abroadsystematically, researched and summarized existing sensor coupling theory.2. Researched the sensing principle of FBG, expounded three mathematic modelsof FBG sensor: stress sensing, temperature sensing and stress-temperature sensing,which provided fundamental basis for subsequent research.3. Based on the sensor’s sensing theory, establish the mathematic model of fiberBragg grating strain sensor. Through the study of the materials and structure of thesensor, the establishment of finite element model of elastomeric on the staticcharacteristics and dynamic characteristics of elastomeric, thermal properties and thecharacteristics of four kinds of thermal coupling analysis, get the four kinds of stressand strain distribution of elastomeric, analysis of the elastomeric screw hole, back tothe tank’s influence on the thermal stress distribution, get the design theory and method of sensor under the thermal-mechanical coupled.4. By encapsulated strain sensors for strain, temperature, thermal coupling and aseries of verification experiments. Analysis of sensor repetition characteristics, linearcharacteristics, hysteresis characteristics, and temperature characteristics. Researchthe change rule between the sensitivity of strain transducer and temperature under thethermal-mechanical coupled. The experiment shows that fiber grating strain sensorscan satisfy the strain measurement under the thermal-mechanical coupledenvironment.