scholarly journals Lightweight Cellulose/Carbon Fiber Composite Foam for Electromagnetic Interference (EMI) Shielding

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1319 ◽  
Author(s):  
Ran Li ◽  
Huiping Lin ◽  
Piao Lan ◽  
Jie Gao ◽  
Yan Huang ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
Electromagnetic Interference ◽  
Fiber Composite ◽  
Carbon Fiber Composites ◽  
Shielding Effectiveness ◽  
Electromagnetic Interference Shielding ◽  
Carbon Fiber Composite ◽  
Foaming Process ◽  
Long Carbon Fibers

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).

EMI Shielding Effectiveness of Polyvinyl Chloride and Carbon Fiber Composites in Building Construction

2014 ◽  
Vol 895 ◽  
pp. 452-459 ◽  
Author(s):  
Mohd Shafiq Ruslan ◽  
Sue Ping Chew ◽  
Mahadi Sharif ◽  
A.A. Azid ◽  
A. Yusof
Keyword(s):  
Carbon Fiber ◽  
Electromagnetic Radiation ◽  
Polyvinyl Chloride ◽  
Electromagnetic Interference ◽  
Fiber Composite ◽  
Building Construction ◽  
Carbon Fiber Composites ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Carbon Fiber Composite

Electromagnetic Interference (EMI) shielding materials commonly refers to how effective the material in limiting the passage of electromagnetic radiation into the devices. This undesired interference may cause disturbances to the performance of the any electrical systems. Thus, with effective EMI shielding materials, electromagnetic radiations are blocked with barriers made of conductive materials. In military field, the operation of certain communication equipments such as radar system can be interfered by disturbances due to the electromagnetic radiation emitted by external sources. This paper presents the investigations on non-metal materials which are Polyvinyl Chloride (PVC) and carbon fiber composite as EMI shielding materials in building construction. These shielding materials are placed in the concrete block which casted based on the standard wall building of grade 30. These customized structures are proven to reduce signal penetration significantly in the high frequency range up to 2.4 GHz.

Interlaminar fracture toughness and electromagnetic interference shielding of hybrid-stitched carbon fiber composites

2018 ◽  
Vol 37 (18) ◽  
pp. 1131-1141 ◽  
Author(s):  
Nisrin R Abdelal ◽  
Steven L Donaldson
Keyword(s):  
Fracture Toughness ◽  
Carbon Fiber ◽  
Electromagnetic Interference ◽  
Experimental Results ◽  
Mode I ◽  
Carbon Fiber Composites ◽  
Interlaminar Fracture Toughness ◽  
Shielding Effectiveness ◽  
Electromagnetic Interference Shielding ◽  
Interlaminar Fracture

In the current study, the production of multifunctional hybrid-stitched composites with improved interlaminar fracture toughness and electromagnetic interference shielding effectiveness is reported. Unidirectional carbon fiber-epoxy composite laminates stitched with Kevlar, nylon, hybrid stitched with both Kevlar and nylon and unstitched were prepared using resin infusion process. Representative specimens from unstitched and stitched composites were tested using rectangular waveguide and Mode I double cantilever beam tests. The Mode I experimental results showed that composite stitched with Kevlar exhibited the highest crack initiation interlaminar fracture toughness (GIC-initiation), whereas composite stitched with nylon exhibited the highest maximum crack propagation interlaminar fracture toughness (GIC-maximum). The four-hybrid stitching patterns exhibited higher GIC-initiation than the unstitched and stitched with nylon composites and lower than stitched with Kevlar composite, whereas they had higher GIC-maximum than the unstitched and stitched with Kevlar composites, although lower than stitched with nylon composite. The electromagnetic shielding effectiveness experimental results showed that stitched composites exhibited improved shielding effectiveness compared to unstitched composites. For example, composite stitched with nylon had highest shielding effectiveness value of 52.17 dB compared by the composite stitched with Kevlar which had 40.6 dB. The four hybrid-stitched composites exhibited similar shielding effectiveness with an average value of 32.75 dB compared to the unstitched composite shielding effectiveness of 22.84 dB. The experimental results comply with the initial goal of this study to manufacture multifunctional hybrid stitching composites with combined properties between Kevlar and nylon-stitched composites.

scholarly journals Design of Low Cost Carbon Fiber Composites via Examining the Micromechanical Stress Distributions in A42 Bean-Shaped versus T650 Circular Fibers

2021 ◽  
Vol 5 (11) ◽  
pp. 294
Author(s):  
Imad Hanhan ◽  
Michael D. Sangid
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
Fiber Composite ◽  
Low Cost ◽  
Complex Loading ◽  
Fiber Composites ◽  
Production Costs ◽  
Carbon Fiber Composites ◽  
Stress Distributions ◽  
Carbon Fiber Composite

Recent advancements have led to new polyacrylonitrile carbon fiber precursors which reduce production costs, yet lead to bean-shaped cross-sections. While these bean-shaped fibers have comparable stiffness and ultimate strength values to typical carbon fibers, their unique morphology results in varying in-plane orientations and different microstructural stress distributions under loading, which are not well understood and can limit failure strength under complex loading scenarios. Therefore, this work used finite element simulations to compare longitudinal stress distributions in A42 (bean-shaped) and T650 (circular) carbon fiber composite microstructures. Specifically, a microscopy image of an A42/P6300 microstructure was processed to instantiate a 3D model, while a Monte Carlo approach (which accounts for size and in-plane orientation distributions) was used to create statistically equivalent A42/P6300 and T650/P6300 microstructures. First, the results showed that the measured in-plane orientations of the A42 carbon fibers for the analyzed specimen had an orderly distribution with peaks at |ϕ|=0∘,180∘. Additionally, the results showed that under 1.5% elongation, the A42/P6300 microstructure reached simulated failure at approximately 2108 MPa, while the T650/P6300 microstructure did not reach failure. A single fiber model showed that this was due to the curvature of A42 fibers which was 3.18 μm−1 higher at the inner corner, yielding a matrix stress that was 7 MPa higher compared to the T650/P6300 microstructure. Overall, this analysis is valuable to engineers designing new components using lower cost carbon fiber composites, based on the micromechanical stress distributions and unique packing abilities resulting from the A42 fiber morphologies.

Electromagnetic interference shielding of stitched carbon fiber composites

2018 ◽  
Vol 49 (6) ◽  
pp. 773-790 ◽  
Author(s):  
Nisrin Abdelal
Keyword(s):  
Carbon Fiber ◽  
Electromagnetic Interference ◽  
Axial Direction ◽  
Fiber Direction ◽  
Carbon Fiber Composites ◽  
Shielding Effectiveness ◽  
Electromagnetic Interference Shielding ◽  
Electromagnetic Interference Shielding Effectiveness ◽  
Carbon Fiber Epoxy ◽  
Representative Samples

This study reports on the improvements in the electromagnetic interference shielding effectiveness of unidirectional carbon fiber-epoxy composites as a results of stitching with conductive and nonconductive threads. Unidirectional carbon fiber laminates stitched with copper, titanium, Kevlar metallic, Kevlar 10 and Dyneema T90 threads were manufactured using vacuum assisted resin infusion process. Representative samples from each laminate were tested in directions normal and axial to the fiber direction using rectangular waveguide. Experimental results showed that composites with improved shielding effectiveness in both directions were produced. For example, stitching with copper doubled the shielding effectiveness in the axial direction when compared to the unstitched laminate. In addition, composite stitched with Dyneema exhibited the most balanced increase in the shielding effectiveness in both axial and normal directions (91.5% and 17.3%, respectively) compared to the unstitched laminate. The shielding mechanism of the composites was mainly reflection.

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