Nondestructive evaluation of hidden damages in glass fiber reinforced plastic by using the terahertz spectroscopy

  • Do-Hyoung Kim
  • Chung-Hyeon Ryu
  • Sung-Hyun Park
  • Hak-Sung KimEmail author
Regular Paper


In this work, the terahertz (THz) spectroscopy system was used for the detecting and evaluation of hidden damages in a glass fiber reinforced plastic (GFRP). The interaction between THz and the GFRP was analyzed including the effects of reflecting, scattering and absorption of THz radiations with respect to the type of hidden damage. Both the transmission and reflective configurations were used to investigate the hidden damages including the delamination, fiber fracture and moisture absorption. Finally, the hidden damages inside of the composite laminates were successfully imaged simultaneously based on the time-domain spectroscopy of THz radiation. Additionally, the moisture absorption damage in the GFRP could be detected by analyzing of the frequency domain spectrum. It is expected that the developed THz nondestructive evaluation (NDE) technique can be widely used to evaluate the health of the composite structures.


Non-destructive evaluation Glass fiber reinforced plastic Delamination Failure modes 



Reflectance for s-polarized THz wave


Reflectance for p-polarized THz wave


Reflectance for THz wave


Transmittance for THz wave


Refractive index of incidence materials


Refractive index of refraction materials


Refractive index


Incidence angle of THz wave


Refractive angle of the THz wave


Absorbance of refraction material


Initial power of THz wave


Thickness of specimen


Absorption coefficient of refractive materials


Relative permittivity of the material


Relative permeability of the material


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Copyright information

© Korean Society for Precision Engineering 2017

Authors and Affiliations

  • Do-Hyoung Kim
    • 1
  • Chung-Hyeon Ryu
    • 1
  • Sung-Hyun Park
    • 1
  • Hak-Sung Kim
    • 1
    • 2
    Email author
  1. 1.Department of Mechanical Convergence EngineeringHanyang UniversitySeoulSouth Korea
  2. 2.Institute of Nano Science and TechnologyHanyang UniversitySeoulSouth Korea

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