Research On Solid Pressure Sensing Technology For High-Temperature Measurement Based On Fiber Bragg Grating

With the continuous development of high performance missiles and other high-end weapons,ammunition is more and more destructive,making ammunition in the process of storage,maintenance and use,reasonable preservation becomes particularly important.Under the circumstances of accidental thermal stimulation,direct ignition by fire or absorption of large amounts of thermal-fire by explosion on the battlefield,the ammunition may be accidentally ignited,thus causing uncontrollable chemical reactions.When the ammunition is stimulated by heat,the pressure inside the projectile body will increase sharply under the influence of the temperature change,which may lead to the detonation of the projectile body,which will not only cause the normal function of the ammunition loss,but also may further cause serious loss of life and property.Therefore,the degree of thermal roast burning experiment was carried out on the live,ammunition heat stability test,internal pressure test,thus learning can play contains material reaction intensity,and the detection of projectile in the heating process was the change of temperature,pressure,the study of the safety and environment adaptability of ammunition system,exert essential and important impact on practice.The thesis talks about the factors to improve the performance of fiber Bragg grating solid pressure sensing under high temperature environment are studied for the practical application of pressure monitoring in ammunition interior thermal safety detection.Firstly,a package structure model which can realize solid pressure sensing is designed and constructed to optimize the temperature compensation effect of the sensor.Secondly,through the data processing of the designed sensor temperature and pressure calibration data,the compensation effect and the accuracy of the sensor are improved.The specific research points of this thesis are as follows:(1)According to the characteristics of temperature and pressure in shell pressure detection environment,the sensing mechanism of fiber Bragg grating solid pressure detection is analyzed,and the high temperature pressure sensing model and temperature compensation treatment method are established.The simulation and calculation of the theoretical model provide theoretical support for the design of sensor structure and related parameters.(2)Aiming at the change of material parameters of packaging materials at different temperatures,the changing trend of pressure sensitivity at different temperatures is obtained through theoretical analysis and model simulation of packaging structure and material parameters.By establishing an experimental platform and carrying out pressure calibration experiments under different temperature environments,the feasibility of high-temperature pressure detection with high-temperature resistant fiber Bragg grating sensor is verified,providing a new research method for high-temperature solid pressure detection technology.(3)Aiming at the conversion accuracy of grating demodulator,static and dynamic information in the detection data of fiber Bragg grating can be extracted effectively.According to the characteristics of the sensor nonlinear changes occur at high temperatures,extreme learning machine model,is presented in this thesis the pressure sensitive grating and removing the temperature of the grating experiment data for training,establish a nonlinear model of wavelength,temperature,predict the experimental temperature,then the temperature data of pressure-sensitive grating the training set of training samples,the nonlinear model,temperature-wavelength prediction test set sample output wavelength,achieve the goal of improved temperature compensation method.(4)A multivariate regression analysis model was established for the characteristics of the non-linear transformation of the sensor's pressure sensitivity with temperature.Based on the linearization process,the linearized model was solved using Python 3.6 as a tool.To achieve the detection effect of all test data,the absolute error of the predicted pressure is less than 0.5Mpa.