Fiber Bragg Grating Transient Strain Signal Detection Techniques

Dynamic Strain is a kind of sudden stress wave which engendered by the launch trajectory. It wildly exists in mechanical system. Launch trajectory system can be monitored and analyzed and the components can be designed with measured dynamic strain. The traditional measurement is electro-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. The strain (thousands of micro-strain) of high-speed launch system is changed quickly in milliseconds, which can not be satisfied for the testing requirement by the traditional measurement. As a result of that, Fiber Grating sensor is produced as a new kind of optical passive components. But it is only explorative research which uses the Fiber Bragg Grating to measure dynamic strain in the system of launch trajectory.In this paper, the working principle of the Fiber Grating sensor is researched. The sensing principle of the Fiber Bragg Grating is skillfully mastered, and the application all over the world is introduced in detail. Characters of many kinds of dynamic strain measuring methods are researched and compared. The dynamic strain measuring system with Fiber Bragg Grating based on unbalanced M-Z interference system and the three-step phase-shift algorithm is designed. The principle of the design of this system is introduced in detail, and the characters of the optic and circuit elements are analyzed. Three kinds of plans are discussed and one of the best is used. Calibration experiment is performed on the platform putting up by ourselves. The data is processed and analyzed by Matlab to calibrate the strain parameters of the system. At last, experiment is performed on the high-speed launch system and the data is collected and analyzed to verify the reasonable and effective of the system.