Shielding Effectiveness and Sheet Conductance of Nonwoven Carbon-Fiber Sheets

TY - JOUR

T1 - Shielding Effectiveness and Sheet Conductance of Nonwoven Carbon-Fiber Sheets

AU - Dawson, J F

AU - Austin, A N

AU - Flintoft, I D

AU - Marvin, A C

N1 - © 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

PY - 2017/2/1

Y1 - 2017/2/1

N2 - Nonwoven carbon-fiber sheets are often used to form a conductive layer in composite materials for electromagnetic shielding and other purposes. While a large amount of research has considered the properties of similar idealized materials near the percolation threshold, little has been done to provide validated analytic models suitable for materials of practical use for electromagnetic shielding. Since numerical models consume considerable computer resource and do not provide the insight which enables improved material design, an analytic model is of great utility for materials development. This paper introduces a new theoretical model for the sheet conductance of nonwoven carbon-fiber sheets built on the theory of percolation for 2-D conducting stick networks. The model accounts for the effects of sample thickness, fiber angle distribution, and contact conductance on the sheet conductance. The theory shows good agreement with Monte Carlo simulations and measurements of real materials in the supercritical percolation regime where the dimensionless areal concentration of fibers exceeds about 50. The theoretical model allows the rapid prediction of material shielding performance from a limited number of manufacturing parameters.

AB - Nonwoven carbon-fiber sheets are often used to form a conductive layer in composite materials for electromagnetic shielding and other purposes. While a large amount of research has considered the properties of similar idealized materials near the percolation threshold, little has been done to provide validated analytic models suitable for materials of practical use for electromagnetic shielding. Since numerical models consume considerable computer resource and do not provide the insight which enables improved material design, an analytic model is of great utility for materials development. This paper introduces a new theoretical model for the sheet conductance of nonwoven carbon-fiber sheets built on the theory of percolation for 2-D conducting stick networks. The model accounts for the effects of sample thickness, fiber angle distribution, and contact conductance on the sheet conductance. The theory shows good agreement with Monte Carlo simulations and measurements of real materials in the supercritical percolation regime where the dimensionless areal concentration of fibers exceeds about 50. The theoretical model allows the rapid prediction of material shielding performance from a limited number of manufacturing parameters.

KW - Carbon-fiber composite

KW - electromagnetic shielding effectiveness

KW - nonwoven fabric

KW - percolation theory

KW - sheet conductance

UR - http://www.scopus.com/inward/record.url?scp=84994008592&partnerID=8YFLogxK

U2 - 10.1109/TEMC.2016.2601658

DO - 10.1109/TEMC.2016.2601658

M3 - Article

SN - 0018-9375

VL - 59

SP - 84

EP - 92

JO - IEEE Transactions on Electromagnetic Compatibility

JF - IEEE Transactions on Electromagnetic Compatibility

IS - 1

M1 - 7565608

ER -