Strain Sensing in Fiber-Reinforced Polymer Laminates Using Embedded Fiber Bragg Grating Sensor

This article demonstrates the use of an embedded fiber Bragg grating sensor for strain measurement at different directions to the loading axis of a fiber-reinforced polymer laminate. Four 16-layer samples have been fabricated with glass cloth and epoxy resin with the fiber Bragg gratings embedded at different angles. The fiber Bragg gratings were interrogated with the help of a paired long-period grating to convert the wavelength change into an optical intensity change. It has been seen that there is a similar to 30% decrease of strain at 30 degrees and a similar to 90% decrease at 60 degrees to the loading direction for an applied strain in the range of 0-9,000 mu strain.