scholarly journals NDE Detection Techniques and Characterization of Aluminum Wires Embedded in Honeycomb Sandwich Composite Panels Using Terahertz Waves

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1264 ◽  
Author(s):  
Kwang-Hee Im ◽  
Sun-Kyu Kim ◽  
Jong-An Jung ◽  
Young-Tae Cho ◽  
Yong-Deuck Woo ◽  
...  
Keyword(s):  
Carbon Fibers ◽  
Sandwich Panels ◽  
Sandwich Composite ◽  
Composite Panels ◽  
Fiber Reinforced ◽  
Terahertz Waves ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Honeycomb Sandwich ◽  
Honeycomb Sandwich Composite

For many years, scientists have been aware of the importance of terahertz waves (T-rays), which have now emerged as an NDE (nondestructive evaluation) technique for certain ranges of the electronic spectrum. The present study deals with T-ray scanning techniques of honeycomb sandwich composite panels with a carbon-fiber-reinforced plastic (CFRP) skin as well as the refractive index (n), and the electrical conductivity (α) of glass fiber-reinforced plastic (GFRP) composites. For this experiment, the degree of penetration to FRP composites is investigated for the THz transmitted power based on the angle in the electric field (E-field) direction vs. the direction of the unidirectional carbon fibers. Also, when CFRP skin honeycomb sandwich panels are manufactured for use in aerospace applications, aluminum wires are twisted together into the one-sided surface of the honeycomb sandwich panels to protect against thunderstorms. The aluminum wires are partly visible because they are embedded in the CFRP skin on the honeycomb sandwich panels. After finishing work with a paintjob, the wires become invisible. Thus, detecting the aluminum wires is a key issue for product monitoring. Based on a simple resistor model, an optimal scanning method is proposed to determine the preferred scan orientation on the baseline of the E-field in the direction of fibers to evaluate the level of transmission of T-rays according to the frequency bandwidth. Thus, the combination of angles required to detect the aluminum wires embedded with carbon fibers on the surface of the composite panels can be determined.

Modeling and characterization of fiber-reinforced plastic honeycomb sandwich panels for highway bridge applications

2001 ◽  
Vol 52 (3-4) ◽  
pp. 441-452 ◽  
Author(s):  
Julio F Davalos ◽  
Pizhong Qiao ◽  
X Frank Xu ◽  
Justin Robinson ◽  
Karl E Barth
Keyword(s):  
Sandwich Panels ◽  
Highway Bridge ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Honeycomb Sandwich

scholarly journals NDE Terahertz Wave Techniques for Measurement of Defect Detection on Composite Panels of Honeycomb Sandwiches

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1360
Author(s):  
Kwang-Hee Im ◽  
Sun-Kyu Kim ◽  
Jong-An Jung ◽  
Young-Tae Cho ◽  
Yong-Deuck Woo ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Electric Field ◽  
Terahertz Wave ◽  
Sandwich Composite ◽  
Fiber Direction ◽  
Composite Panels ◽  
Terahertz Waves ◽  
Electric Field Direction ◽  
Honeycomb Sandwich ◽  
Honeycomb Sandwich Composite

Terahertz wave (T-ray) technologies have become a popular topic in scientific research over the last two decades, and can be utilized in nondestructive evaluation (NDE) techniques. This study suggests an optimal scanning technique method for honeycomb sandwich composite panels, where skins were utilized with two different skins, namely, carbon fiber-reinforced plastic (CFRP) skin and glass fiber-reinforced plastic (GFRP) skin, as layers of the panel surfaces. Foreign objects were artificially inserted between the skins and honeycomb cells in the honeycomb sandwich composite panels. For this experiment, optimal T-ray scanning methods were performed to examine defects based on the angle between the one-ply thin fiber skin axis and the angle of the electric field (E-field) according to the amount of conductivity of the honeycomb sandwich composite panels. In order to confirm the fundamental characteristics of the terahertz waves, the refractive index values of the GFRP composites were experimentally obtained and analyzed, with the data agreeing with known solutions. Terahertz waves (T-rays) were shown to have limited penetration in honeycomb sandwich composite panels when utilized with a skin of carbon fibers. Therefore, T-rays were found to interact with the electrical conductivity and electric field direction of honeycomb sandwich composite panels with glass fiber skins. The T-ray images were obtained regardless of the electric field direction and the fiber direction. In the honeycomb sandwich composite panels with carbon fiber skins, the T-ray images with higher signal-to-noise (S/N) ratios depended on the scanning angle between the angle of the carbon fiber and the angle of the electric field. Thus, the angle of optimum detection measurement was confirmed to be 90° between the E-field and the fiber direction, particularly when using a carbon fiber skin.

Critical shear loading of curved sandwich panels faced with fiber-reinforced plastic

AIAA Journal ◽  
1986 ◽  
Vol 24 (9) ◽  
pp. 1531-1536 ◽  
Author(s):  
Koganti Mohana Rao ◽  
H. R. Maeyer-Piening
Keyword(s):  
Sandwich Panels ◽  
Shear Loading ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic

Development of PCD Milling Tool for Carbon-Fiber-Reinforced Plastics

2014 ◽  
Vol 1017 ◽  
pp. 411-414
Author(s):  
Takayuki Kitajima ◽  
Jumpei Kusuyama ◽  
Akinori Yui ◽  
Katsuji Fujii ◽  
Yosuke Itoh
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
Polycrystalline Diamond ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastics ◽  
Reinforced Plastic ◽  
Milling Tool ◽  
Fiber Reinforced Plastics ◽  
Carbon Fiber Reinforced

Interest in carbon-fiber-reinforced plastic (CFRP) has been growing for the last several years. CFRP, a composite material made of carbon fibers and resins, has high mechanical characteristics and is well known as a difficult-to-cut material. During the process of drilling or cutting of CFRP, tool wear and delamination occur frequently. In this study, the authors developed a milling tool for CFRP using polycrystalline diamond, and the cutting performance of the developed tool was investigated.

Lightweight Hybrid Composites of CFRP and Aluminum Foam

2015 ◽  
Vol 825-826 ◽  
pp. 482-489
Author(s):  
Christian Fiebig ◽  
Michael Koch
Keyword(s):  
Aluminum Foam ◽  
Volume Fraction ◽  
Hybrid Composites ◽  
Minimum Weight ◽  
Sandwich Composite ◽  
Sandwich Composites ◽  
Damping Properties ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic

The lightweight potential of components made of fiber-reinforced plastic can be enhanced by use of sandwich composites. So far, limited dynamic properties of plastic-based foams have prevented the use of sandwich composites in machine applications. The combination of closed-cell aluminum foam (ALF) and carbon fiber reinforced plastic (CFRP) provides a solution to this obstacle. Aluminum foam is characterized by favorable damping properties with minimum weight and CFRP provides high strength and stiffness at similarly low density. This paper deals with the design of a hybrid sandwich composite and its interpretation by using customized FEM simulations.Producing this kind of a sandwich composite in an economic production process presents a major challenge. Thus, a method has been developed that prevents excessive penetration of the resin into the pores of the aluminum foam. A high volume fraction of the resin in the foamed sandwich core would increase density and negatively influence damping properties. The implementation of a barrier layer will avoid this penetration. A DoE was developed and RTM process parameters were varied with the objective of achieving the highest specific bending stiffness. In preliminary experiments the appropriate range of injection pressure, mold temperature, and pressure force was determined. Tests with a nonwoven fabric could prevent the resin from infiltrating into the aluminum foam. Mechanical properties of the sandwich composite are only marginally affected.A model was developed to calculate the obtainable sandwich composite properties. The calculation method considers both the characteristics of the aluminum foam and the CFRP anisotropy. Based on this model a reliable calculation of the applied load could be accomplished. The design of the sandwich composite was targeting at high stiffness and determination of the natural frequency. Parallel to calculations, tests on specimen were performed and the obtained results were included into the calculation as part of the material model.

Damage Tolerance of Honeycomb Sandwich Composite Panels

2002 ◽  
Author(s):  
Bert L. Smith ◽  
John S. Tomblin ◽  
K. S. Raju ◽  
K. H. Liew ◽  
A. K. M. Haque ◽  
...  
Keyword(s):  
Damage Tolerance ◽  
Sandwich Composite ◽  
Composite Panels ◽  
Honeycomb Sandwich ◽  
Honeycomb Sandwich Composite

scholarly journals A Numerical Analysis of Reinforced T Shaped Concrete Beams by Polymeric Strap of CFRP and GFRP with Finite Element Method Technique

2018 ◽  
Vol 4 (5) ◽  
pp. 1006 ◽  
Author(s):  
Mehrdad Marefat Naeini ◽  
Sayed Mahdi Moghadasi ◽  
Mostafa Omidi Bidgoli
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Analysis ◽  
Carbon Fibers ◽  
Concrete Beams ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Two Samples ◽  
Element Method

In recent decades, researchers and structural engineers have shown great interest in the use of Fiber Reinforced Polymer (FRP) plates/sheets for maintaining strength and durability in the utilization of concrete structures. In this study, reinforced-concrete beam with T-shaped cross-section is reinforced with Carbon Fiber Reinforced Plastic (CFRP) plates and Glass Fiber Reinforced Plastic (GFRP) plates under 4-points inflections by finite element method. In order to analyze the performance of the polymer plates used in the reinforcement of the considered concrete beams, some sheets with 5cm and 10 cm width having different formation patterns are joined to the concrete area. For this purpose, the angle between the lines of the plates and the longitudinal axis of the beam is varied based on four different degrees of gradations, from 30 to 90°. In addition, the role of these sheets in limiting the deformation of the beam in its U-shaped and full-wrapping conditions is studied. The transversal distance between the plates is also considered as equal to the width of plates. Seventy-two samples of concrete beams with C30 and C50 grades which were strengthened with polymer plates are compared with non-polymeric concrete beams. The numerical analysis results illustrate that the use of the different formation patterns and deflection angle of plates cause differences in the process of beam settlement. Further, the results show that C50 grade concrete samples are most effective in the reduction of concrete deformation when carbon fibers of 5cm width are used at an angle of 30 degrees with beam linear axis and traversal formation pattern. On the other hand, among the C30 grade samples, the best performance is related to the use of 5 cm carbon fibers which were utilized as full-wrapping. Under both aforementioned circumstances, the possible amount of the polymeric beam settlement over non-polymeric beam will decrease by about 50%.

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