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Development of Real-Time Cure Monitoring System of FRP Laminates

Kengo Terada, Tatsuro Kosaka and Kazuhiro Kusukawa


Our study focuses development of real-time cure monitoring system for FRP prepregs using Fresnel-based fiber-optic sensors. The sensor can measure changes in refractive index of resin and degree-of-cure can be calculated from the measured value and temperature. However, during hot-press molding using prepregs, the sensor outputs show large fluctuation induced by air-voids near the sensor tip before melting temperature of B-stage matrix, and the fluctuation decreased measurement accuracy. In the present study, calculation method of degree-of-cure was improved using measurement of absolute refractive index of resin. In addition, a real-time filter was introduced into the monitoring system for elimination of the noise effect. The experimental results were discussed in comparison with cure process simulation. From the results, it appeared that the present monitoring system could measure degree-of-cure of FRP prepregs precisely in real-time.

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