Study On The Profiled Beam Fiber Grating Vibration Sensor

There are a lot of vibration problems in our daily life and work，some vibrationwill endanger people’s lives and work. However, the stringent requirements on theaccuracy of measurement can not be achieved by conventional electromagnetic typesensors. In order to keep the security of people’s lives and properties away fromdanger, accurate measurements of various small vibrations are of great significance.At present, fiber grating sensor which based on the grating as the sensing element isone of the rapider developing vibration measurement devices. Compared with theelectromagnetic sensors, it has many outstanding advantages, such as wavelengthencoding, small size, light weight, high sensitivity, strong anti-jamming capability,and compact. Therefore, the investigations on the grating acceleration-basedvibration sensor technology are very important.The design and measurement methods for processing sensitizing groove on abasis of equal strength cantilever beam fiber grating profiled vibration sensor werereported, and the feasibility analysis and experimental research were carried out inthis thesis.The developments and characteristics of the conventional types of vibrationsensors, fiber optic sensors and the ones with grating as the sensing element wereintroduced in this thesis. The production of sensitive components, working principleand wavelength demodulation method were generalize, and the quasi-linearrelationship between the light intensity and wavelength was obtained through theCWDM linear sideband as well as mathematical calculations of sensitive elementspectrum characteristics. The finite element analysis software was used to optimizethe designing and modal analysis of cantilever to design the profiled beam gratingvibration sensor head, and a self warmed profiled beam was designed for sensortemperature effect. The experimental system of the sensor was set up, and temperature and vibration characteristics of the sensor head were studied. Theexperimental and theoretical results show that the vibration sensitivity of the systemis76.22pm/g, and the natural frequency of the system is182Hz.