Estimation of the transverse coefficient of thermal expansion on carbon fibers at very high temperature

The main objective of this work is to present a new method for measuring the transverse coefficient of thermal expansion (CTE) of fibers at very high temperature. The difficulty of the measurement is due to the thin fiber diameter (approximate to 10 mu m), the low variation with temperature of the fiber diameter (approximate to 10-30nm), and finally the important range of temperature (300-2800K). An experimental device was designed for the measurement and an inverse method has been developed for identification. The characterization, with a confidence interval lower than 8%, of tungsten and carbon fibers allows the validation of this device and the related estimation method.