Fiber-optic composite cure sensor: monitoring the curing process of composite material based on intensity modulation

With the aid of the latest fiber-optic sensing technology, parameters in the cure process of thermosetting resin composite can be monitored entirely and efficiently. Based on the behavior of the refractive of resin matrix and intensity modulation of the transmitted light, experiment results of viscosity measurement in composite cure process using fiber-optic sensors are presented. The sensor signal can be used to monitor the process, detect the time when the viscosity of resin matrix is lowest and the end of the cure without calibration. The experiments of monitoring curing process of composite materials are successively made in hot-press, model autoclave and large autoclave in the manufacture field, the results are consistent and fit very well with the results of numerical simulation and the results monitored by dynamic dielectric sensor. With this technology, the cure process becomes more apparent and controllable, which will greatly improve the cured products and reduce the cost.