光纤模斑谱传感器复合材料固化监测研究

提出利用一种新型光纤传感器，通过测量光纤末端近场模斑谱反映光纤埋置周围树脂折射率的变化．计算了随着树脂固化过程中折射率变化的功率谱密度分布，给出截止频率与折射率的近似关系．给出了利用这种传感器进行复合材料树脂固化监测的实验结果．发现这种光纤传感器的信号可以用来反映固化凝胶点和固化结束点．由于固化后光纤仍保持光波导特性，该光纤还可以用来监测结构受环境的扰动如温度变化、振动等．

Curing Process Monitoring for Composite Materials by Using Fiber Optic Sensor

A new fiber optic sensor is designed for monitoring the curing process of composite materials. By measuring the speckle spatial spectrum at the endface of the fiber optic embedded in the material, the variation in refractive index for the resin surrounding the fiber is then observed. An approximate relation between the refractive index and the cutoff frequency of the spectrum is given. A typical experiment is reported. The fiber optic sensor can also be used to detect the gel point and the end point of the curing process. In view that the fiber optic maintains its wave guide performance after curing process, it could also be used for sensing such factors as temperature variation and mechanical vibration during structure service.