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Article
Publication date: 19 March 2020

Xinjin Liu, Xinxin Yan, Xuzhong Su and Juan Song

With the popularization of electronic products, the electromagnetic radiation pollution has been the fourth largest pollution after water, air and noise pollution. Therefore…

Abstract

Purpose

With the popularization of electronic products, the electromagnetic radiation pollution has been the fourth largest pollution after water, air and noise pollution. Therefore, electromagnetic shielding property of textiles is attracting more attention. In this paper, the properties of electromagnetic shielding yarns and fabrics were studied.

Design/methodology/approach

Ten kinds of yarn, stainless steel short fiber and polyester blend yarn with three different blending ratios T/S 90/10, T/S 80/20 and T/S 70/30, stainless steel short fiber, polyester and cotton blend yarn with blending ratio C/T/S 35/35/30, core-spun yarn with one 30 um stainless steel filament C/T28tex/S(30 um), core-spun yarn with two 15 um stainless steel filaments (C/T28tex/S(15 um)/S(15 um)), twin-core-spun yarn with one 30 um stainless steel filament and one 50D spandex filament C/T28tex/S(30 um)/SP(50D), sirofil wrapped yarn with one 30 um stainless steel filament feeding from left S(30 um)+C/T28tex, sirofil wrapped yarn with one 30 um stainless steel filament feeding from right C/T28tex+S(30 um), sirofil wrapped yarn with two 15 um stainless steel filaments feeding from two sides S(15 um)+C/T28tex+ S(15 um), were spun. The qualities of spun yarns were measured. Then, for analyzing the electromagnetic shielding properties of fabrics made of different spun yarns, 20 kinds of fabrics were woven.

Findings

The tested results show that comparing to the T/S 80/20 blend yarn, the resistivity of composite yarns with the same ratio of the stainless steel filament is smaller. The possible reason is that comparing to the stainless steel short fiber, the conductivity of stainless steel filament is better because of the continuous distribution of stainless steel in the filament. Comparing with the core-spun yarn, the conductivity of the sirofil wrapped yarn is a little better. Comparing to the fabric woven by the blend yarn, the electromagnetic shielding of the fabric woven by the composite yarn is better, and comparing to the fabric woven by the core-spun yarn, the electromagnetic shielding of the fabric woven by the sirofil yarn is a little better. The possible reason is that the conduction network can be produced by the stainless steel filament wrapped on the staple fiber yarn surface in the fabric, and the electromagnetic wave can be transmitted in the network.

Originality/value

In this paper, the properties of electromagnetic shielding yarns and fabrics were studied. Ten kinds of yarn, including three stainless steel short fiber and polyester blend yarns, one stainless steel short fiber, polyester and cotton blend yarn, two core-spun yarns, one twin-core-spun yarn, three sirofil wrapped yarn, were spun. Then, for analyzing the electromagnetic shielding properties of fabrics made of different spun yarns, 20 kinds of fabrics were woven. The effects of fabric warp and weft densities, fabric structures, yarn kinds, yarn distributions in the fabric on electromagnetic shielding were analyzed.

Details

International Journal of Clothing Science and Technology, vol. 32 no. 5
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 30 October 2020

Xiuchen Wang, Zhe Liu, Long Wu, Yue Wang and Ying Su

The change rules of the shielding effectiveness (SE) of the sleeve has not been clarified, which leads to the lack of the basis for the design, manufacture and evaluation of the…

Abstract

Purpose

The change rules of the shielding effectiveness (SE) of the sleeve has not been clarified, which leads to the lack of the basis for the design, manufacture and evaluation of the electromagnetic shielding (EMS) clothing.

Design/methodology/approach

According to a simplified analysis model, a series of sleeve samples with different fabrics and styles are designed and manufactured. The SE of the sleeve is tested with the proposed special test method in a semi-anechoic chamber to analyze the influence of different factors on the SE of the sleeve.

Findings

The SE is greatly reduced about 60–90% after the fabric is manufactured into the sleeve. The larger the sleeve length is, the higher the peak value of the SE is. When the sleeve length is low, the SE value is easy to appear negative. As the cuff circumference increases, the SE of the sleeve will change with the frequency band. The influence of the cuff style on the SE of the sleeve mainly depends on the cuff width and style. The larger the cuff width is, the lower the overall SE of the sleeve is. The more wrinkles there are at the cuff, the better the SE of the sleeve is.

Originality/value

Our results provide a reference for the design, production and evaluation of the sleeve and the whole EMS clothing.

Details

International Journal of Clothing Science and Technology, vol. 33 no. 2
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 7 September 2015

Zhe Liu, Xing Rong, Xiuchen Wang and Zhong Zhou

The purpose of this paper is to explore the influence of hole on shielding effectiveness (SE) of electromagnetic shielding (EMS) fabric under incident polarization wave, and to…

Abstract

Purpose

The purpose of this paper is to explore the influence of hole on shielding effectiveness (SE) of electromagnetic shielding (EMS) fabric under incident polarization wave, and to propose a “Key Size” theory to explain the influence mechanism.

Design/methodology/approach

“Key Size” parameters describing hole shape are established, and a number of representative samples with rectangular and oval holes are made. SE of the samples are tested by waveguide testing system. Influence of the hole on the SE of the samples is analyzed according to vertical or horizontal maximum size and polarization wave direction. Finally, the “Key Size theory” and “Secondary Size theory” are proposed to explain the influencing mechanism.

Findings

The hole influences on the SE are related to the vertical and the horizontal maximum size of the holes and the direction of the polarization wave. As the direction of the polarization wave is vertical (or horizontal), greater maximum size results in lower SE. As the maximum size is constant, greater maximum size causes lower SE. As the maximum size reaches to a certain value, a dividing point of the SE occurs. As the direction of the polarization wave is consistent with the direction of the maximum size, same hole area results in same SE.

Originality/value

The explored influences and mechanism provide an important guiding reference for the hole design of the EMS fabric, and can be applied to the holes design of the EMS garment, composite materials, and tents.

Details

International Journal of Clothing Science and Technology, vol. 27 no. 5
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 6 March 2017

Xiuchen Wang, Yaping Li, Ying Su, Zhen Pan and Zhe Liu

The three-dimensional arrangement structure of the conductive fiber is an important factor of the shielding effectiveness of the electromagnetic shielding fabric (EMSF). However…

Abstract

Purpose

The three-dimensional arrangement structure of the conductive fiber is an important factor of the shielding effectiveness of the electromagnetic shielding fabric (EMSF). However, until now, the three-dimensional arrangement structure has not been described because of the complex structure, which leads to many difficulties for the subsequent analysis of the electromagnetic characteristics. Therefore, the purpose of this paper is to propose a feature extraction method to describe the arrangement structure of the conductive fiber based on the three-dimensional calibration and image processing technology, providing a new idea for the above problem.

Design/methodology/approach

First, the three-dimensional positions of the conductive fibers in the EMSF are calibrated using the VHX-600 3D digital microscope and the MATLAB7.5 software. The arrangement characteristics of the conductive fibers are analyzed, and equivalent twist, cross-sectional content, and average angle of a single fiber are proposed to describe the arrangement characteristic of the conductive fiber. Then, a digital description model of the conductive fiber is constructed according to the feature parameters and its three-dimensional structures are reproduced using CATIA. Finally, the reliability of the model is verified by an FDTD example, and the significance and application of the model are given.

Findings

The proposed method can provide the feature extraction and description for the complex spatial three-dimensional arrangement structure of conductive fibers. The feature parameters can reflect different micro arrangement features of the conductive fiber. The proposed idea and method can provide a solid foundation for subsequent studies of the electromagnetic properties of the EMSF.

Originality/value

The study in this paper is of great significance and academic value. This paper provides a new three-dimensional calibration method and constructs multiple feature parameters to describe the complex three-dimensional arrangement structure, providing a new effective method to overcome the problem of the conductive fiber description. The proposed method provides an important basis for the shielding mechanism, transmission characteristics, electromagnetic calculation and product design, and woven technology of the EMSF.

Details

International Journal of Clothing Science and Technology, vol. 29 no. 1
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 26 August 2014

Xiuchen Wang, Zhe Liu, Zhong Zhou, Qing He and Haoxian Zeng

The purpose of this paper is to propose a new indicator-gray porosity that can objectively evaluate real porosities of electromagnetic shielding (EMS) fabric based on computer…

Abstract

Purpose

The purpose of this paper is to propose a new indicator-gray porosity that can objectively evaluate real porosities of electromagnetic shielding (EMS) fabric based on computer image analysis, which aims to address current porosity evaluation by tightness.

Design/methodology/approach

A method for the fabric image acquisition is determined and a gray digital model is established. The porosity membership region of true porosity is judged according to the total gray wave. A bi-directional judgment method based on horizontal and vertical single gray waves is proposed to automatically identify the gray porosity in the porosity membership region. After experiments, the differences between the gray porosity indicator and the tightness indicator are analyzed, the influence of the gray porosity on the shielding effectiveness (SE) is discussed, and the advantages of the gray porosity indicator are detailed.

Findings

Results show that the proposed indicator can accurately represent the real porosity size of the EMS fabric without pre-acquiring the structure parameters of the fabric, which provides a reference for the study of the electromagnetic characteristic of the EMS fabric.

Originality/value

The gray porosity presented in this paper is a new method to objectively evaluate real porosities of the EMS fabric, and can be applied to the research and evaluation of the electromagnetic characteristic for the EMS fabric.

Details

International Journal of Clothing Science and Technology, vol. 26 no. 5
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 5 March 2018

Ling Weng, Ting Wang, Pei-Hai Ju and Li-Zhu Liu

This paper aims to develope the electromagnetic interference shielding materials with high performance. To develop advanced polymer-based electromagnetic interference shielding

Abstract

Purpose

This paper aims to develope the electromagnetic interference shielding materials with high performance. To develop advanced polymer-based electromagnetic interference shielding materials with rather high temperature stability, good processability and moderate mechanical properties, the authors chose the polyimide (PI) foam as matrix and ferriferrous oxide (Fe3O4) as fillers to prepare the composite foams with lightweight and rather good electromagnetic interference shielding performance.

Design/methodology/approach

Some polyimide nanocomposite foams with Fe3O4 as fillers have been prepared by in situ dispersion and foaming with pyromellitic dianhydride (PMDA) and isocyanate (PAPI) as raw materials and water as foaming agent. By varying the Fe3O4 contents, a series of PI/Fe3O4 nanocomposite foams with fine microstructures and high thermal stability were obtained. The structure and performances of nanocomposite foams were examined, and the effects of Fe3O4 on the microstructure and properties of composite foams were investigated.

Findings

This work demonstrates that PI/Fe3O4 foams could be fabricated by thermally treating the polyimide foam intermediates with Fe3O4 nanoparticles through a blending reaction of precursors. The final PI/Fe3O4 composite foams maintained the excellent thermal property and showed a super paramagnetic behaviour, which has a positive effect on the improvement of electromagnetic shielding performance.

Research limitations/implications

In this paper, the effects of Fe3O4 on the performances of PI/Fe3O4 composite foam were reported. It provided an effective methodology for the preparation of polymer/Fe3O4 nanocomposite foams, which hold great promise towards the potential application in the areas of electromagnetic shielding materials.

Originality/value

A series of PI/Fe3O4 composite foams with different contents of Fe3O4 were prepared by blending reaction of the precursors. The effects of Fe3O4 on the structures and properties of PI/Fe3O4 composite foam were discussed in detail.

Details

Pigment & Resin Technology, vol. 47 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 16 August 2021

Zhiguang Cheng, Behzad Forghani, Zhenbin Du, Lanrong Liu, Yongjian Li, Xiaojun Zhao, Tao Liu, Linfeng Cai, Weiming Zhang, Meilin Lu, Yakun Tian and Yating Li

This paper aims to propose and establish a set of new benchmark models to investigate and confidently validate the modeling and prediction of total stray-field loss inside…

126

Abstract

Purpose

This paper aims to propose and establish a set of new benchmark models to investigate and confidently validate the modeling and prediction of total stray-field loss inside magnetic and non-magnetic components under harmonics-direct current (HDC) hybrid excitations. As a new member-set (P21e) of the testing electromagnetic analysis methods Problem 21 Family, the focus is on efficient analysis methods and accurate material property modeling under complex excitations.

Design/methodology/approach

This P21e-based benchmarking covers the design of new benchmark models with magnetic flux compensation, the establishment of a new benchmark measurement system with HDC hybrid excitation, the formulation of the testing program (such as defined Cases I–V) and the measurement and prediction of material properties under HDC hybrid excitations, to test electromagnetic analysis methods and finite element (FE) computation models and investigate the electromagnetic behavior of typical magnetic and electromagnetic shields in electrical equipment.

Findings

The updated Problem 21 Family (V.2021) can now be used to investigate and validate the total power loss and the different shielding performance of magnetic and electromagnetic shields under various HDC hybrid excitations, including the different spatial distributions of the same excitation parameters. The new member-set (P21e) with magnetic flux compensation can experimentally determine the total power loss inside the load-component, which helps to validate the numerical modeling and simulation with confidence. The additional iron loss inside the laminated sheets caused by the magnetic flux normal to the laminations must be correctly modeled and predicted during the design and analysis. It is also observed that the magnetic properties (B27R090) measured in the rolling and transverse directions with different direct current (DC) biasing magnetic field are quite different from each other.

Research limitations/implications

The future benchmarking target is to study the effects of stronger HDC hybrid excitations on the internal loss behavior and the microstructure of magnetic load components.

Originality/value

This paper proposes a new extension of Problem 21 Family (1993–2021) with the upgraded excitation, involving multi-harmonics and DC bias. The alternating current (AC) and DC excitation can be applied at the two sides of the model’s load-component to avoid the adverse impact on the AC and DC power supply and investigate the effect of different AC and DC hybrid patterns on the total loss inside the load-component. The overall effectiveness of numerical modeling and simulation is highlighted and achieved via combining the efficient electromagnetic analysis methods and solvers, the reliable material property modeling and prediction under complex excitations and the precise FE computation model using partition processing. The outcome of this project will be beneficial to large-scale and high-performance numerical modeling.

Article
Publication date: 16 April 2020

Paul Clérico, Xavier Mininger, Laurent Prévond, Thierry Baudin and Anne-Laure Helbert

This paper aims to investigate the efficiency of a laminated composite for shielding applications. The solution has to be efficient not only for the shield against static magnetic…

Abstract

Purpose

This paper aims to investigate the efficiency of a laminated composite for shielding applications. The solution has to be efficient not only for the shield against static magnetic fields but also “for low-frequency ones, in order to be well-suited for applications with electromagnetic perturbations in the frequency range DC to 100 kHz.”

Design/methodology/approach

The composite constituted of a steel sheet taken in a sandwich between two aluminum (Al) sheets is produced by cold roll bonding. A good adherence between Al and steel sheets, ensuring a good mechanical resistance, is obtained with a specific process. A previous study has shown that the optimal trade-off between adherence and magnetic shielding effectiveness (SEH) is obtained with a 230 µm composite produced with an initial thickness of Al and steel sheets, respectively, of 250 and 100 µm. In this paper, the 230 µm Al/steel/Al composite is used in three applications modelized by two-dimensional numerical simulations. To obtain reasonable computation time for the simulations, a homogenization method is applied to the composite. Studied applications are a cylindrical box containing a coil, a square box under an external magnetic field and a high voltage cable.

Findings

In each application, SEH is calculated at low frequency and different materials (Al/steel/Al, Al, steel and copper) are compared. It is observed that, in each application, the composite presents higher SEH at equal mass, especially for frequencies between 5 and 100 kHz.

Originality/value

The proposed approach, from the material point of view to the system consideration, shows that the thin bimetallic composite is an innovative and promising solution for magnetic shielding in the case of applications with both DC and low-frequency perturbations.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 39 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 6 July 2015

Elzbieta Lesniewska

The purpose of this paper is to discuss the operation of new generation electromagnetic current-to-voltage transducer. The aim of research was analysis of behaviour of considered…

Abstract

Purpose

The purpose of this paper is to discuss the operation of new generation electromagnetic current-to-voltage transducer. The aim of research was analysis of behaviour of considered current-to-voltage transducers during operation. The main problem was to estimate whether the external fields are able to change the value of the secondary voltage and that the replacement of the casing material by a conductive or ferromagnetic material will increase the immunity of the transducer to external magnetic fields. The immunity of current-to-voltage transducers to the external fields is very important because it influences the proper functioning of the protection system.

Design/methodology/approach

The use of analytical methods to assess the influence of external fields was impossible due to the complexity of the geometry. The 3D computations were necessary because of different cross sections of circuit boards at different heights. Therefore the numerical 3D field-and-circuit method based on finite element method was applied. The wide range of dimensions in computation system, ranging from 0.15 mm (print paths) to 0.22 m, made it necessary to use the mesh of millions of elements. The division of this type of system into elements requires a diverse and extremely dense mesh in the area of printed circuits board (PCBs).

Findings

The 3D analysis of magnetic field distribution was performed for different external field effect upon a current-to-voltage transducer. The magnetic field distributions and the induced secondary voltage for several different cases were presented. As a conclusion it can be said that in this particular case the magnetic shield is most effective. The influence of external magnetic fields caused by currents passing through the other neighbouring phase bars near are insignificant for the transducer with non-magnetic core.

Practical implications

Commonly used in measuring and protection systems of the transmission lines are induction instrument transformers. The instrument transformers are very precise devices and their errors are counted in tenths of a per cent, and phase displacement of signals in minutes. Especially in HV systems they are very big and their cores are heavy. Replacement of instrument transformers by the current to voltage transducers cooperating with electronic measuring systems will reduce the size and cost of devices.

Originality/value

The requirements set for protective current transformers concern the transformation of currents, with high accuracy, especially at transient states. Therefore magnetic characteristics of their cores should be linear. It causes that cores are large and have some air gaps. Current-to-voltage transducers based on Rogowski coil are particularly suitable for the replacement of the protective current transformers because of their linearity. The traditional technologies used for making Rogowski coil consisted in winding a wire on a non-magnetic carcass. The development of technology has enabled the use of new technologies PCB high density interconnect in the production of Rogowski coil.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 6 July 2012

Daniele Desideri, Alvise Maschio, Marco Bolzan, Marco Natali and Monica Spolaore

The purpose of this paper is to obtain a multidisciplinary characterization of nanostructured copper films for electromagnetic shields.

Abstract

Purpose

The purpose of this paper is to obtain a multidisciplinary characterization of nanostructured copper films for electromagnetic shields.

Design/methodology/approach

Structural and electrical analysis have been applied, on copper nanometric films produced by a magnetron sputtering device.

Findings

Data are provided for copper films realized by magnetron sputtering deposition on glass, in different operating conditions.

Practical implications

A multidisciplinary comprehension of shielding effectiveness of nanostructured thin films can be important in many applications where there are electromagnetic compatibility problems.

Originality/value

The paper gives a valuable set of information for the characterization of nanometric copper thin films.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

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