T-Ray NDE Inspections on the Fiber Direction of Thermoplastic PPS-Based CFRP Composites

Terahertz ray (T-ray) imaging has been emerged as one of the most promising new powerful nondestructive evaluation (NDE) techniques, and new application systems are under processing development for the area applications. The terahertz time domain spectroscopy (THz TDS) can be considered as a useful tool using general non-conducting materials; however it is quite limited to conducting materials. In this study, a new time-domain spectroscopy system was utilized for detecting and evaluating layup effect and flaw in FRP composite laminates. In order to solve various material properties, the index of refraction (n) and the absorption coefficient (α) are derived in reflective and transmission configuration using the terahertz time domain spectroscopy. However, the T-ray is limited in order to penetrate a conducting material to some degree. So, investigation of terahertz time domain spectroscopy (THz TDS) was made and reflection and transmission configurations were studied for a 48-ply thermoplastic PPS (poly-phenylene sulfide)-based CFRP solid laminate.

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Terahertz Ray Nondestructive Characterizations in FRP Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.123-125.839 ◽

2010 ◽

Vol 123-125 ◽

pp. 839-842 ◽

Cited By ~ 5

Author(s):

Je Woong Park ◽

Kwang Hee Im ◽

David K. Hsu ◽

Chien Ping Chiou ◽

Daniel J. Barnard

Keyword(s):

Composite Laminates ◽

Electromagnetic Properties ◽

Reflection Mode ◽

Frp Composites ◽

Frp Composite ◽

Application Systems ◽

Spectroscopy System ◽

Terahertz Ray ◽

Characterization Procedure ◽

Good Agreement

Recently, terahertz ray imaging has emerged as one of the most promising new powerful nondestructive evaluation (NDE) techniques, and new application systems are under processing development for the area applications. In this study, a new time-domain spectroscopy system was utilized for detecting and evaluating layup effect and flaw in FRP composite laminates. Extensive experimental measurements in reflection mode were made to map out the T-ray images. Especially in this characterization procedure, we estimated the electromagnetic properties such as the refractive index. Estimates of properties are in good agreement with known data. Furthermore layup effect and flaw of FRP composite laminates were observed in reflection mode and limitations will be discussed in the T-ray processing.

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Terahertz Wave Approach and Application on FRP Composites

Advances in Materials Science and Engineering ◽

10.1155/2013/563962 ◽

2013 ◽

Vol 2013 ◽

pp. 1-10 ◽

Cited By ~ 6

Author(s):

Kwang-Hee Im ◽

David K. Hsu ◽

Chien-Ping Chiou ◽

Daniel J. Barnard ◽

Jong-An Jung ◽

...

Keyword(s):

Electrical Conductivity ◽

Nondestructive Evaluation ◽

Carbon Fibers ◽

Time Domain ◽

Index Of Refraction ◽

Polyphenylene Sulfide ◽

Fiber Axis ◽

Terahertz Time Domain Spectroscopy ◽

Time Domain Spectroscopy ◽

Cfrp Composites

Terahertz (THz) applications have emerged as one of the most new powerful nondestructive evaluation (NDE) techniques. A new T-ray time-domain spectroscopy system was utilized for detecting and evaluating orientation influence in carbon fiber-reinforced plastics (CFRPs) composite laminates. Investigation of terahertz time-domain spectroscopy (THz-TDS) was made, and reflection and transmission configurations were studied as a nondestructive evaluation technique. Here, the CFRP composites derived their excellent mechanical strength, stiffness, and electrical conductivity from carbon fibers. Especially, the electrical conductivity of the CFRP composites depends on the direction of unidirectional fibers since carbon fibers are electrically conducting while the epoxy matrix is not. In order to solve various material properties, the index of refraction (n) and the absorption coefficient (α) are derived in reflective and transmission configurations using the terahertz time-domain spectroscopy. Also, for a 48-ply thermoplastic polyphenylene-sulfide-(PPS-) based CFRP solid laminate and nonconducting materials, the terahertz scanning images were made at the angles ranged from0°to180°with respect to the nominal fiber axis. So, the images were mapped out based on the electrical field (E-field) direction in the CFRP solid laminates. It is found that the conductivity (σ) depends on the angles of the nominal axis in the unidirectional fiber.

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