Damage Investigation in Beam Structures using Fiber Optic Polarimetric Sensors

The Fiber Optic Polarimetric Sensor (FOPS) is an attractive technology for global damage detection of mechanical and civil structures providing real time structural health monitoring (SHM). In this technology the concept of a Dynamic damage factor (DDF) was proposed [3] as a global health indicator of the structure. However, the crack size and location could not be determined. In this paper, the effects of the size and the location of a single crack on the frequency of first fundamental mode of beam structures are further studied. The relation between relative change in the modal frequency and the relative size of a crack has been established theoretically and then verified experimentally. Experimental results confirm that the change in frequency of first mode provides damage information of structure. It is further shown that the size and location of a crack in the beam structures can also be identified.