Development of measuring CME technology using optics

Abstract

CFRP (Carbon Fiber Reinforced Plastic) has been used for space structures generally because of its high strength, stiffness, light weight and low thermal expansion. Especially, CTE (Coefficient of Thermal Expansion) of CFRP is much lower than that of metals so CFRP has been used for precision like space telescopes. But recently, accuracy demands for high precision space structures have become increasingly stringent. To meet these requirements, not only thermal expansion but moisture expansion of CFRP has to be considered. Measuring moisture expansion requires long term experiments, and state of the art measurement systems were unable to provide sufficient stability and accuracy. A new method for measuring the moisture expansion of CFRP using optical interferometry was developed. Using this method, CFRP moisture expansion was evaluated stably at high accuracy.