• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.3
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• pp.173-180
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• 2001

In the past few years, the nondestructive inspection technology has greatly developed due to the increased necessity to gain a complete understanding of the bridge behavior. Especially, the deformations of bridges contain a lot of informations about its health state. By measuring these deformations it is possible to analyze the loading and aging behavior of the structure. However, the current, methods (such as LVDT, dial gage, optical displacement transducer, etc) are often of changeable application on site and have the limitations of installation. In this paper, the classical beam theory was reviewed and the deflections of structure are estimated using measured strain which is easy to acquire. The applicability of this algorithm is verified by laboratory(simple reinforced concrete beam) and field test. By this test, we proposed correction factor to estimate deflection of reinforced concrete beam after cracking, and analyze about the generation of correction factor. Also fiber optic sensors as well as resistive strain gages were installed in the concrete beams to establish the applicability of fiber optic sensors in the field of civil engineering.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.5
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• pp.513-516
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• 2011

The dynamic behavior of a small wind-turbine blade was analyzed experimentally. Arrays of fiber Bragg-Grating (FBG) sensors attached along the blade were used to measure the strains of the blade surface. An impact test was performed to estimate the resonance frequencies of the fundamental and higher modes of the cantilever blade system developed for this study. The results were similar to the results for conventional strain gages. However, FBG sensors could sense modes that strain gauges could not sense. The strains obtained from the FBG sensor array were used to estimate displacement-mode shapes of the blade.