抄録
Infrared stress measurement technique is applied for non-destructive evaluation of composites with advantage of in-situ and non-contact nature. Thermo-elastic constants of unidirectional carbon-epoxy (CFRP) needed for quantitative measurements are obtained by the infrared stress graphic system. The theoretical thermo-elastic constants are derived through the basic equations and compared with the experimental values. As a consequence, a reliability of the measured thermo-elastic constants is established and capability of this system for quantitative stress measurement is shown. It is also demonstrated that temperature dependency of a transverse coefficient of thermal expansion and a specific heat at constant stress of UD-CFRP cancel each other so as to decrease the temperature dependency of the thermo-elastic constant. This finding can be considered as an advantage of the infrared stress measurement for CFRP. In addition, other influential factors on the measurements are examined. In conclusion, basic knowledge and detailed technique for quantitative infrared stress measurements of CFRP are established.
