Influence of Terahertz Waves on Unidirectional Carbon Fibers in CFRP Composite Materials

  • Kwang-Hee IM Woosuk University
  • David Kuei HSU Iowa State University
  • Chien-Ping CHIOU Iowa State University
  • Daniel J. BARNARD Iowa State University
  • Sun-Kyu KIM Chonbuk Natl. University
  • Sung-Jun KANG Chonbuk Natl. University
  • Young-Tae CHO Jeonju University
  • Jong-An JUNG Songwon University
  • In-Young YANG Chosun University
Keywords: Terahertz Waves, Unidirectional CFRP Composites, Carbon Fiber, Reflection, Transmission Mode


Terahertz time domain spectroscopy (THz TDS) system based on the reflective and through-transmission modes was utilized. Influence of terahertz waves (T-ray) on the fiber surface layups in the CFRP solid composites was studied. It was found that the value of electrical conductivity in the carbon fibers varies by the layup directions of carbon fibers based on E-field (Electrical field). T-ray optimized scanning data could be obtained at the 90° angle normal to the E-field direction. GFRP (Glass-fiber reinforced plastics) composite laminates were scanned with two saw cuts using a T-ray THz TDS system and the terahertz optimized scanning images were obtained at the angles normal to the E-field direction on the nonconducting materials. Also, by use of 2-dimensional spatial Fourier transform, interface C-scan images were transformed into quantitative angular distribution plots in order to show the fiber orientation information therein and to make the orientation of the ply predictable.