A fiber-optic cure monitoring technique with accuracy improvement of distorted embedded sensors

A fiber-optic epoxy cure monitoring technique for efficient wind turbine blade manufacturing and monitoring is presented. To optimize manufacturing cycle, fiber-optic sensors are embedded in composite materials of wind turbine blades. The reflection spectra of the sensors indicate the onset of gelification and the completion of epoxy curing. After manufacturing process, the same sensors are utilized for in-field condition monitoring. Because of residual stresses and strain gradients from the curing process, the embedded sensors may experience distortions in reflection spectra, resulting in measurement errors. We applied a Gaussian curve-fitting algorithm to the distorted spectra, which substantially improved the measurement accuracy.