A calculating method for the electromagnetic shielding effectiveness of metal fiber blended fabric

2017 ◽  
Vol 88 (9) ◽  
pp. 973-986 ◽  
Author(s):  
Ranran Liang ◽  
Wenjuan Cheng ◽  
Hong Xiao ◽  
Meiwu Shi ◽  
Zhanghong Tang ◽  
...  

In order to obtain a simple and accurate calculation method of shielding effectiveness for woven fabric containing metal fiber yarns, a conductive grid structure model composed of two parallel metal yarn periodic arrays was established. The two periodic arrays were cross-arrangement. The calculation formula of shielding effectiveness for the fabric was deduced through the transfer matrix of the electromagnetic field. The theoretical value of shielding effectiveness of the fabric using the theoretical formula and the measured value tested by the shielding chamber method were compared. Both sets of data were analyzed respectively from the metallic yarn periodic spacing, diameter, electric conductivity, electromagnetic wave polarization direction, and the weaving angle. The result shows that a reasonable agreement between the theoretical value and the measured value has been achieved in a frequency range from 4 to 14 GHz. This shows that the theoretical calculation model is simple, highly precise, and is valuable for the design and development of fabric containing metal fiber yarns. It can be used for estimating the electromagnetic shielding effectiveness of the fabric.

2020 ◽  
Vol 90 (21-22) ◽  
pp. 2504-2521
Author(s):  
Veronika Tunakova ◽  
Maros Tunak ◽  
Pavla Tesinova ◽  
Marie Seidlova ◽  
Jiri Prochazka

At present, much attention is focused on developing clothing fabrics with advanced functionality without compromising their visual, mechanical, or comfort properties. A fabric’s ability to prevent the penetration of electromagnetic radiation is an interesting added feature. In the published literature, there are many references describing the development and investigation of electromagnetic shielding textile structures using different electrically conductive additives. However, little attention has been given to the aesthetic and comfort properties of these special fabrics. Moreover, the availability of everyday fashion containing electromagnetic radiation protection is very limited. For this study, woven fabric made from a mixture of traditional fibers and extremely thin discrete stainless steel fibers developed in the authors’ previous research was used as a substrate. The fabric was digitally printed to provide an interesting design effect suitable for use in clothing and for making clothes for everyday wear. The main objective of this work is to determine whether digital printing is a suitable tool for changing the color and pattern of this metal fiber-containing fabric. The individual goals are (a) to examine the fabric’s color fastness to washing and (b) to investigate whether the surface modification of the fabric adversely affects its functionality. Results show that it is possible to change the color and pattern of metal fiber-containing fabric by digital printing easily, whereas the associated decrease of porosity causes an increase of this special fabric functionality. The electromagnetic shielding effectiveness of the fabric after printing is around 33 dB for frequency 1.5 GHz. However, washing has a negative effect, causing both the electromagnetic shielding ability decrease (to 27 dB for frequency 1.5 GHz after 20 washing and drying cycles) and color fading (the color fastness grade is around 1–2 after 20 washing and drying cycles). Furthermore, the basic transport properties of printed electrically conductive fabric are compared with those of fabric made from traditional material and positive results are found. The incidence of pilling after washing is also evaluated, whereas the first pills are observed after the eighth washing and drying cycle. Finally, clothing prototypes that could be prepared from printed fabric are presented.


2019 ◽  
Vol 14 ◽  
pp. 155892501986096 ◽  
Author(s):  
Ilkan Özkan ◽  
Abdurrahman Telli

In this study, stainless steel, copper, and silver wires were intermingled with two polyamide 6.6 filaments through the commingling technique to produce three-component hybrid yarns. The produced hybrid yarns were used as weft in the structure of plain woven fabric samples. The electromagnetic shielding effectiveness parameters of samples were measured in the frequency range of 0.8–5.2 GHz by the free space technique. The effects of metal hybrid yarn placement, number of fabric layers, metal types, and wave polarization on the electromagnetic shielding effectiveness and absorption and reflection properties of the woven fabrics were analyzed statistically at low and high frequencies separately. As a result, the samples have no shielding property in the warp direction. Metal types show no statistically significant effect on electromagnetic shielding effectiveness. However, fabrics containing stainless steel have a higher absorption power ratio than copper and silver samples. Double-layer samples have higher electromagnetic shielding effectiveness values than single-layer fabrics in both frequency ranges. However, the number of layers does not have a significant effect on the absorbed and reflected power in the range of 0.8–2.6 GHz. There was a significant difference above 2.6 GHz frequency for absorbed power ratio. An increase in the density of hybrid yarns in the fabric structure leads to an increase in the electromagnetic shielding effectiveness values. Two-metal placement has a higher absorbed power than the full and one-metal placements, respectively. The samples which have double layers and including metal wire were in their all wefts reached the maximum electromagnetic shielding effectiveness values for stainless steel (78.70 dB), copper (72.69 dB), and silver composite (57.50 dB) fabrics.


2015 ◽  
Vol 749 ◽  
pp. 265-269 ◽  
Author(s):  
Jia Horng Lin ◽  
Ting An Lin ◽  
Chien Teng Hsieh ◽  
Jan Yi Lin ◽  
Ching Wen Lou

This study uses 0.08mm copper wire and nickel-coated copper wire as the core and 75 D far infrared filament as the wrapped material to manufacture Cu/FIR-PET wrapped yarn, Ni-Cu/FIR-PET wrapped yarn and Ni-Cu/Cu/FIR-PET wrapped yarn. The three optimum metallic/FIR-PET wrapped yarns are then weaving into Cu/FIR-PET woven fabrics, Ni-Cu/FIR-PET woven fabrics and Ni-Cu/Cu/FIR-PET woven fabrics. Tensile property of metallic/FIR-PET wrapped yarns, electrical resistance of metallic/FIR-PET wrapped yarns, surface resistivity of metallic/FIR-PET woven fabrics and electromagnetic shielding effectiveness of metallic/FIR-PET woven fabric are discussed. According to the results, the optimum tenacity and elongation are chosen as 7 turns/ cm, electrical resistance of Ni-Cu/Cu/FIR-PET wrapped presents the best value, Cu/FIR-PET woven fabric has the lowest surface resistivity and Ni-Cu/Cu/FIR-PET woven fabric shows the best EMSE at 37.61 dB when the laminating-layer number is double layer and laminating at 90 ̊. In this study, three kinds of metallic/FIR-PET woven fabrics are successfully manufactured and looking forward to applying on industrial domains.


2014 ◽  
Vol 910 ◽  
pp. 210-213 ◽  
Author(s):  
Jia Horng Lin ◽  
Ting An Lin ◽  
An Pang Chen ◽  
Ching Wen Lou

The electronic appliance is capable of emitting electromagnetic waves that will cause the damage of electrical equipment and influence peoples health. In this study, stain steel filament (SS filament) and 75D PET filament were used to manufacture SS/PET composite yarn The SS/PET composite yarn were made by the wrapping machine, which the core yarn is stain steel filament, wrapped yarn is 75D PET filament and the wrapping layers is varied as one and two. After that, the composite yarn is fabricated by the automatic sampling loom into composite woven fabrics. The composite SS/PET woven fabrics were under the tests of electromagnetic shielding effectiveness (EMSE) and air permeability. The test results revealed that the EMSE of the one-layer composite woven fabric is 9.5 dB at 900 MHz, but the EMSE decreases as test frequency increases. When laminating layer added to three layers, the EMSE raise up to 12.6 dB. The EMSE of composite woven fabric reached at 29.9 when the laminated angle is 45°. And the air permeability decreases as the laminate layer increases, which the thickness of sample affect air to pass through the sample.


2020 ◽  
Vol 15 ◽  
pp. 155892502098595
Author(s):  
Metin Yuksek

The demand for multifunctional requirements in aerospace, military, automobile, sports, and energy applications has encouraged the investigation of new conductive composite fibers. This study focuses on the development of Vapor-grown carbon nanofibers (VGCNFs) filled Polyvinylidene Fluoride (PVDF) composite fibers. Polyvinylidene fluoride (PVDF) reinforced with (1, 3, 5, and 8 wt.%) carbon nanofibers were produced as a masterbatch. The production of PVDF and PVDF/CNF composite fibers have been done successfully by using melt spinning processing technique. Conductive woven fabrics were produced with composite fibers on handloom machines to measure electromagnetic interference (EMI) shielding efficiency. Tensile strength of fibers increased with increase in CNF loading up to 3%. The tensile strength displayed a decrease of 5% and 8% CNF loading. Electromagnetic shielding effectiveness (EMSE) of woven fabrics with composite fibers were tested by using the coaxial transmission line method for planar materials standard that is based on ASTM D 4935-10. The electromagnetic shielding effectiveness of woven fabric which is consist of conductive composite fibers were increased with increasing CNFs loading and amount of fabric layers. It can be seen that the woven fabrics displayed between 2–10 dB and 2–4 dB EMSE values in the 15–600 MHz and 600–3000 MHz-frequency range, respectively. Nevertheless, it was observed that conductive filler content, dispersion, and network formation within the composite fibers were highly influent on the electromagnetic shielding effectiveness performance of the structures.


2021 ◽  
pp. 004051752199489 ◽  
Author(s):  
Yong Wang ◽  
Stuart Gordon ◽  
Weidong Yu ◽  
Zongqian Wang

Textiles that contain integrated conducting components are drawing attention for their ability to mitigate electromagnetic radiation pollution. Maintaining effective and robust electromagnetic shielding effectiveness (EMSE) under different modes, e.g. stretching, bending and washing, is of importance in protecting humans and information-sensitive electronic devices from exposure to electromagnetic interference. In this work, a weft-stretchable, conductive fabric (W-SCF) was specially manufactured for electromagnetic shielding characterization by integrating stainless steel filament (SSF) in the weft direction. The results demonstrate that our as-prepared W-SCF was effective for shielding purpose with its EMSE dependent on the orientation of the SSF within the fabric structure. Specular reflection caused by the close arrangement of the SSF and the lower electrical resistance of the fabric on per unit area basis were responsible for the enhanced shielding properties when the fabric was stretched. Furthermore, using the fabric in a 90°/90° laminated form improved the EMSE values compared with a single layer and a 0°/90° laminated versions. Importantly, the W-SCF exhibited resistance to 10 laundering cycles, 20 stretching cycles (at 25% extension), 50 bending cycles and 100 abrasion cycles, demonstrating its robustness and durability. This work is believed to take a new step in development of reliable and advance shielding materials for special protective application.


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