The strain field method for structural damage identification using Brillouin optical fiber sensing

The theory of the strain field (SF) method using Brillouin optical fiber sensing (BOFS) is proposed for structural damage identification in this paper. Field test verification of this method was carried out by implementing a destructive loading test to an existing prestressed concrete bridge. A series of structural damage scenarios were thus produced for identification. A sub-matrix featuring the damage scenarios was first extracted from the space–time matrix to obtain the strain field distribution in space–time coordinates. Furthermore, other feature extraction operations, including row vector extraction, column vector extraction and boundary extraction, were performed to characterize the structural damage behavior and damage evolution patterns. Finally, damage localization and quantification were successfully implemented in both space and time domains in terms of a damage index vector array. The investigation results demonstrated the SF method using BOFS is a feasible and efficient approach for structural damage identification.