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From the angle of sensitivity of the long period fiber grating (LPFG) resonant transmission spectrum, we demonstrate the sensitivity of LPFG resonance peak amplitude changing with transverse loads. The design of a resonant peak modulation-based LPFG rebar corrosion sensor is described by combining the spectral characteristics of LPFG with the expansion state monitoring of rebar corrosion. LPFG spectrum curves corresponding with different rebar corrosion status of the environment under test are captured by the monitoring technique of LPFG transmission spectra, and the relationship between the resonance peak amplitude change and the state of rebar corrosion is obtained, that is, the variation of LPFG resonance peak amplitude increases with the intensifying of the degree of rebar corrosion. The experimental results numerically show that the sensor response has good regularity for a wide range of travel.

Structural damage localization plays an important role in structural damage identification. An cumulative structural damage localization method based on evidence theory is studied in this paper. An algorithm for cumulative fusion of primary localization information is presented. In the numerical study, a fixed-end beam is inspected. Two damage cases are studied, one with single damage and the other with multiple damages. White noises are added to the beam mode shapes of the first five orders to simulate the measurement noises. First, Modal Strain Energy Change Ratio (MSECR) method is used to localize the damage elements using the noise-contaminated mode shapes. Then, the locations determined by MSECR are taken as primary information and fused cumulatively. In both the single-damage-case and the multiple-damage-case, the fused results show that damaged elements are accurately identified. Furthermore, the damage elements are distinguished much more clearly than those identified from MSECR.