Application Research On Fiber Bragg Grating In Dynamic Strain Measurement

Fiber Grating sensor is one new kind of optical passive components . It has some physical merits , such as light quality,thin diameter and soft characteristic . And it also has some functional merits , such as anti-electromagnetic interference, easy to compose measurement network . Especially ,Fiber Bragg Grating is sensitive to strain which make it to an up-coming new technology to strain measuring .Dynamic Strain is a kind of sudden stress wave which engendered by the impact machine. It widly exists in impact system . Impact system can be monitored and analied and impact componets can be designed with measured the dynamic strain . The traditional measurement is elctro-measure method which measured by the strain gauge . But this method is easy to be effected by the electromagnetic interference and the strain gauge is easily mangled as well. And the strain gauge is hard to compose measurement network.That is groping research which uses the Fiber Bragg Grating to measure dynamic strain in impact machine system. The characteristic points of the essay is as follows:1. Introduction of the status of application of Fiber Bragg Grating and the dynamic strain measuring all over the world. Introduction of discrimination measurement methods of strain and temperature . Derivation of the sensor theory of Fiber Bragg Grating with the coupled-mode formalism.2. Study the characteristic of the stress wave engendered by the coaxal double bar striking . Design of a group of dynamic strain measuring system with Fiber Bragg Grating based on the the phase generated carrier and unbalanced M-Z interference system which the cut-off frequency is 10 kHz.3. Analysis to the theory of the measurement system and the parameter which influenced the capability of the demodulation system.4. Detailed introduction of the design of optic part and circuit part elaborately from the point of choosing optic and circuit element, system data of different part and the principle of the design.5. The Matlab simulating experiment, the standard sine wave driving measuring experiment and the impact signal measuring experiment were made. The results show that the Signal-to-Noise of this system is 80dB and the strain varation is 10-4 when the frequency is under 10kHz .