Lightning Strike Protection and EMI Shielding of Fiber Reinforced Composite Using Gold and Silver Nanofilms

Author(s):  
Praveen K. Bollavaram ◽  
Muhammad M. Rahman ◽  
R. Asmatulu

Carbon fiber reinforced composites are very much imperative to future-generation aircraft structures. However, lightning strike protection (LSP) and electromagnetic interference (EMI) are main concerns. Carbon fibers have very good mechanical properties with the best strength-to-weight ratio, but they are very poor conductors of electricity. These fibers must be reinvented to increase the surface conductance to provide high electrical conductivity to the aircraft structure. The present study deals with preparing composite sandwich structures of carbon fibers used for commercial nacelle applications subject to lightning strike effects with different metallic nanofilm of gold (Au) and silver (Ag) measuring approximately 100 nm. These metallic nanofibers were co-cured on the top layers of composite panels during vacuum curing process. In our laboratory, lightning strike results for a composite sandwich structure using nanofilms were obtained to observe lightning strike damage and structural tolerance necessary to observe the damage tolerance capability. Resistance of composite panels with metallic nanofilm under various strains was studied. It was found that resistance of the metallic nanofilm increased under strain. The voltage was found to be low; hence, an increase in current would help to reduce the damage on composite panels due to lightning strikes, and the same theory would be applicable to EMI. No EMI was absorbed or reflected in the nanofilm using the P-static test. When lightning strikes were applied to composite coupons, the resulting damage from the currents was reduced on those with metallic nanofilms.

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1264 ◽  
Author(s):  
Kwang-Hee Im ◽  
Sun-Kyu Kim ◽  
Jong-An Jung ◽  
Young-Tae Cho ◽  
Yong-Deuck Woo ◽  
...  

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.


2020 ◽  
Vol 54 (29) ◽  
pp. 4547-4555 ◽  
Author(s):  
Siwat Manomaisantiphap ◽  
Vipin Kumar ◽  
Takao Okada ◽  
Tomohiro Yokozeki

A large amount of electrically conductive fillers is needed to enhance a Carbon Fiber Reinforced Plastics (CFRP) electrical conductivity enough to withstand lightning strikes of peak currents. However, such large alien constituents hamper the inherent good mechanical properties of CFRP structures. In this work, a solution has been proposed to retain both desired properties in a CFRP laminate. Layer-wise hybrid laminate has been demonstrated as a solution for lightning strike protection of Carbon Fiber Reinforced Plastics (CFRP). Top few layers of a hybrid laminate are prepared using electrically conductive polymer-based resin (CF/C-POLY) to provide effective dissipation of lightning current while epoxy-based CFRP substrate (CF/Epoxy) provides the main structural strength. An insulating adhesive layer is used to bond CF/C-POLY and CF/Epoxy to prepare the laminate. The hybrid laminates were tested for their effectiveness against lightning strikes. Laminates were struck by modified lightning waveform of component A with peak current of -14 kA and -40 kA. The performance of the laminates against lightning strike were evaluated using high speed camera, high-speed and thermal camera. It is found that CF/C-POLY layer successfully defended the main structural component i.e. CF/Epoxy from lightning direct damage.


2012 ◽  
Vol 224 ◽  
pp. 73-76 ◽  
Author(s):  
Oh Yang Kwon ◽  
Jae Ha Shin

CFRP laminates made of nano-particles-coated carbon fibers and damaged by a simulated lightning strike were tested under the compression-after-impact (CAI) mode, during which the damage progression was monitored by acoustic emission (AE). The effects of nano-particles coating on the degree of lightning-damage and the mechanical integrity of composite structures damaged by lightning strikes have been evaluated in terms of AE activities.


Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 823 ◽  
Author(s):  
Simon Bard ◽  
Florian Schönl ◽  
Martin Demleitner ◽  
Volker Altstädt

In this paper, the thermal and electrical conductivity and mechanical properties of fiber reinforced composites produced from nickel- and copper-coated carbon fibers compared to uncoated fibers are presented. The carbon fibers were processed by our prepreg line and cured to laminates. In the fiber direction, the thermal conductivity doubled from ~3 W/mK for the uncoated fiber, to ~6 W/mK for the nickel, and increased six times to ~20 W/mK for the copper-coated fiber for a fiber volume content of ~50 vol %. Transverse to the fiber, the thermal conductivity increased from 0.6 W/mK (uncoated fiber) to 0.9 W/mK (nickel) and 2.9 W/mK (copper) at the same fiber content. In addition, the electrical conductivity could be enhanced to up to ~1500 S/m with the use of the nickel-coated fiber. We showed that the flexural strength and modulus were in the range of the uncoated fibers, which offers the possibility to use them for lightning strike protection, for heatsinks in electronics or other structural heat transfer elements.


2021 ◽  
pp. 002199832110417
Author(s):  
Pralhad Lamichhane ◽  
Dilli R Dhakal ◽  
Siddhesh Chaudhari ◽  
Ishan N Jayalath ◽  
Toby Nelson ◽  
...  

Multifunctional carbon fiber-reinforced polymer (CFRP) composites are promising structural materials for lightweight applications. However, the low conductivity in the through-thickness direction of the composites limits its applications in the fields that require the high stability of composite against lightning strikes. This work presents the study on the synergetic effect of conducting polymer, polyaniline (PANI), and graphene nanoplatelets (GNP) for increasing the electrical conductivity of CFRP composites. PANI doped GNP flexible film is fabricated with the aid of compatible polymer polyvinylpyrrolidone (PVP), and its effect on the electrical conductivity of CFRP composites has been studied. About 250% in through-thickness conductivity has improved with 11 wt% GNP as a function of the composite. The incorporation of conductive film not only increases the conductivity of the CFRP laminates but also enhances the resistance against lightning strikes. Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), three-point bending tests were used to analyze the morphology, thermal stability, and mechanical strengths of the composites. Finally, the observation of post-strike damage confirms the importance of through-thickness conductivity for mitigating the lightning strike damage.


Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1319 ◽  
Author(s):  
Ran Li ◽  
Huiping Lin ◽  
Piao Lan ◽  
Jie Gao ◽  
Yan Huang ◽  
...  

Lightweight electromagnetic interference shielding cellulose foam/carbon fiber composites were prepared by blending cellulose foam solution with carbon fibers and then freeze drying. Two kinds of carbon fiber (diameter of 7 μm) with different lengths were used, short carbon fibers (SCF, L/D = 100) and long carbon fibers (LCF, L/D = 300). It was observed that SCFs and LCFs built efficient network structures during the foaming process. Furthermore, the foaming process significantly increased the specific electromagnetic interference shielding effectiveness from 10 to 60 dB. In addition, cellulose/carbon fiber composite foams possessed good mechanical properties and low thermal conductivity of 0.021–0.046 W/(m·K).


2020 ◽  
Vol 40 (5) ◽  
pp. 415-420 ◽  
Author(s):  
Yasin Altin ◽  
Hazal Yilmaz ◽  
Omer Faruk Unsal ◽  
Ayse Celik Bedeloglu

AbstractThe interfacial interaction between the fiber and matrix is the most important factor which influences the performance of the carbon fiber-epoxy composites. In this study, the graphitic surface of the carbon fibers was modified with graphene oxide nanomaterials by using a spray coating technique which is an easy, cheap, and quick method. The carbon fiber-reinforced epoxy matrix composites were prepared by hand layup technique using neat carbon fibers and 0.5, 1 and 2% by weight graphene oxide (GO) modified carbon fibers. As a result of SEM analysis, it was observed that GO particles were homogeneously coated on the surface of the carbon fibers. Furthermore, Young's modulus increased from 35.14 to 43.40 GPa, tensile strength increased from 436 to 672 MPa, and the elongation at break was maintained around 2% even in only 2% GO addition.


2016 ◽  
Vol 725 ◽  
pp. 127-131 ◽  
Author(s):  
Kumar V. Akshaj ◽  
P. Surya ◽  
M.K. Pandit

Dent resistance of structures is one of the important design parameters to consider in automotive, aerospace, packaging and transportation of fragile goods, civil engineering and marine industries. It is important to study the dynamic impact response of various combinations of skin and core materials which can provide desired fracture toughness and highest strength to weight ratio for such applications. This paper discusses the low velocity impact response of sandwich structures having unique combination of mild steel as skin material bonded to thermoplastics/PU foam as core material. HDPE, LDPE and polypropylene were the choice of thermoplastics and an optimum combination of materials for the sandwich structure was evaluated using drop-weight experimental set up. It is observed that LDPE is the best choice of core material for the sandwich structures considered.


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