Temperature Compensated Optical Fiber Sensors in Composites

Purpose and goal

The objective was to integrate temperature compensated fiber optic strain gauges in carbon fiber fixtures for aircraft manufacturing. The objectives were: Method for temperature compensation of fiber optic strain gauges in composite materials Experimentally verified functionality A state of the art analysis Three functioning sensor designs with environmental compensation were developed but the measurement uncertainty was inadequate for the intended application. The state of the art analysis confirmed the absence of commercial options and applicable research results.

Expected results and effects

Environment compensated fiber optic strain gauges for surface mounting on carbon fiber fixtures were de-veloped. The measurement uncertainty was estimated to be ± 16 strain, which is not sufficient for the targeted application, aircraft manufacturing. An application in the aerospace industry is therefore unlikely in the near future, and the expected impact in the short term is rather that the acquired knowledge will create a better foundation for future development.

Planned approach and implementation

Initially an analysis was made that provided guidance to the development work. The focus has been practical and different sensor concepts have been evaluated. Due to difficulties with repeatability between different sensors the project´s resources were put on trying to solve these with new sensor design and laboratory testing. Hence, the pre-planned integration of sensors in a veridical application beam did not take place.