Measurement of Material Deformation with Fiber Bragg Gratings (Summarization)

Fiber sensing elements based on Bragg gratings (FBG) are a prospective basis of sensors for detecting deformations in measuring systems, in particular, for integrated control of various structures. The possibility of their application in the structure of polymer composite material for aerospace construction elements is examined. The FBG operating principle is based on change in the period of the grating—the periodic structure of the refractive index of an optical fiber core. Change in the period can cause either thermal expansion or compression of an optical fiber. Therefore, to solve integrated control problems, one has to understand the cause of optical fiber deformation in the area of location of FBG—with change in mechanical loading applied to it or thermal operating conditions. Proposed approaches to the allowance for temperature change when measuring deformation with FBG are systemized and the results of works in this field are presented. Possible implementations of each approach are described. Measurement accuracy of deformation and temperature is determined. The structural scheme of sensing elements is described.