Abstract
Viscous coefficients of CFRP composites that absorb moisture are measured quantitatively and non-destructively by ultrasonic waves. The waves are transmitted through a moisturized unidirectional CFRP laminate which is immersed in water. By measuring the relative amplitudes of transmitted waves at various incident angles, the viscous coefficients are obtained. The moisture absorption is carried out in 60°C hot water for various time period before the specimens become saturated with water. As the moisture content increases, the viscous coefficients increase. Furthermore, these changes are confirmed to be reversible through the measurement after moisture desorption.
