Analysis of Longitudinal Strains of Cross-ply Composite Laminates using A-EFPI Optical Fiber Sensor

다국어 초록 (Multilingual Abstract)

<P>The longitudinal strains (U03B5;<SUB>x</SUB>) of the core and the skin layers in glass fiber reinforced plastic (GFRP) cross-ply composite laminates are analyzed using embedded optical fiber sensors (OFSs) of absolute extrinsic FabryU2014;Perot interferometer (A-EFPI). Foil-type strain gages (SGs) bonded on both upper and lower surfaces of a specimen are employed for comparison of the strain measurement on the surface. It has been shown that the values of U03B5;<SUB>x</SUB> in the interior of the skin layer and the core layer measured by embedded A-EFPI sensor are lower than those of the specimen surface measured by SGs. Experimental results agree well with those from finite element analysis based on a shear lag model. Optical microscopy observation of the damage behavior around the fiber sensor by the thin-sectioning technique shows that reinforcing glass fibers protect the OFS embedded in the 0<SUP> U00B0;</SUP> skin layer, whereas the formation of transverse cracks in the 90<SUP> U00B0;</SUP> core layer substantially reduces strains at the failure of OFS embedded in the core layer.</P>