Research Of The Fiber Grating Displacement Sensor Design Based On SMA

Fiber Bragg grating is sensors with excellent properties and has very broad application prospects in the field of civil aircraft structural health monitoring. With the improvement of modern civil aircraft performance, large complex aircraft structure deformation and displacement monitoring of fiber Bragg grating sensor is put forward new requirements. The research introduces the status quo of fiber Bragg grating sensor in the field of civil aviation aircraft structure monitoring, and put forward a kind of optical fiber grating displacement sensor based on shape memory alloy which uses shape memory alloy deformation flexibility and the characteristics of arbitrariness, by shape memory effect of the auxiliary optical fiber grating into S type. The research is in three aspects on mechanical analysis, finite element simulation of sensor and sensor performance test. The main research content is as follows:First, this paper expounds the shape memory alloy and the basic theory of fiber Bragg grating sensor. Using large curvature of curved bar model, the relationship between the change of the wavelength of the fiber Bragg grating displacement sensor and displacement change "S" shape memory alloy is deduced. Using the finite element software to simulate "S" shape memory alloy and to study the shape memory alloy under different displacement load of the structure of the strain changes. The spectrum simulation results of optical fiber Bragg grating displacement sensor is based on ANSYS simulation.Second, fiber Bragg grating displacement sensor based on shape memory alloy is designed and developed, using the shape memory effect of shape memory alloy to drive soft deformation of fiber Bragg grating sensors. Through tensile tests of fiber Bragg grating displacement sensor, the relationship between sensor center wavelength, spectral bandwidth and reflected light intensity with different strength and displacement is studied.Finally, by monitoring the impact of the honeycomb sandwich composite material specimen and stretch of the carbon fiber composite joint, the application of optical fiber Bragg grating displacement sensor is carried out to explore research, for this kind of sensor applied in aircraft structure experimental guidance for the structural health monitoring.