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An Electromagnetic Sensor with a Metamaterial Lens for Nondestructive Evaluation of Composite Materials.

Savin A, Steigmann R, Bruma A, Šturm R - Sensors (Basel) (2015)

Bottom Line: These structures can serve as electromagnetic flux concentrators in the radiofrequency range.The evaluation method is based on the appearance of evanescent modes in the space between carbon fibers when the sample is excited with a transversal magnetic along z axis (TMz) polarized electromagnetic field.The flaws can be localized with spatial resolution better than λ/2000.

View Article: PubMed Central - PubMed

Affiliation: Nondestructive Testing Department, National Institute of R&D for Technical Physics, 47 D. Mangeron Blvd, 700050 Iasi, Romania. asavin@phys-iasi.ro.

ABSTRACT
This paper proposes the study and implementation of a sensor with a metamaterial (MM) lens in electromagnetic nondestructive evaluation (eNDE). Thus, the use of a new type of MM, named Conical Swiss Rolls (CSR) has been proposed. These structures can serve as electromagnetic flux concentrators in the radiofrequency range. As a direct application, plates of composite materials with carbon fibers woven as reinforcement and polyphenylene sulphide as matrix with delaminations due to low energy impacts were examined. The evaluation method is based on the appearance of evanescent modes in the space between carbon fibers when the sample is excited with a transversal magnetic along z axis (TMz) polarized electromagnetic field. The MM lens allows the transmission and intensification of evanescent waves. The characteristics of carbon fibers woven structure became visible and delaminations are clearly emphasized. The flaws can be localized with spatial resolution better than λ/2000.

No MeSH data available.


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Studied samples: (a) Photo; (b) 5HS woven layout.
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sensors-15-15903-f006: Studied samples: (a) Photo; (b) 5HS woven layout.

Mentions: Figure 6 presents the studied samples and the layout of five harness satin woven of carbon fibers. The plates were subjected to impacts with energies of 2, 4, 6, 8, 10 and 12 J. The composite plates exhibit electric properties that depend on the type of carbon fibers and on their volume fraction in the material, having the transverse electric conductivity between 10 S/m and 100 S/m and longitudinal conductivity ranging between 5 × 103 S/m and 5 × 104 S/m. The samples were impacted using a FRACTOVIS PLUS 9350-CEAST instrument (Instron, Norwood, MA, USA) with a hemispherical bumper head having 20 mm diameter and 2.045 kg weight, in order to induce delaminations. The impact data were recorded with a DAS16000 acquisition system (Instron) with a sampling frequency of 1 MHz [59]. For higher energy impacts, local deformations result in delamination propagation, deviation and/or breaking of the carbon fibers. In both cases, the modification of local conductivity allows the damage detection using electromagnetic methods [60]. Typical records of force vs. time during impact can give information about the CFRP status (delaminated or not) [61]. Thus, only plates that show delamination were used in the study, meaning the plates impacted with 6 J, 8 J, 10 J and 12 J.


An Electromagnetic Sensor with a Metamaterial Lens for Nondestructive Evaluation of Composite Materials.

Savin A, Steigmann R, Bruma A, Šturm R - Sensors (Basel) (2015)

Studied samples: (a) Photo; (b) 5HS woven layout.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541860&req=5

sensors-15-15903-f006: Studied samples: (a) Photo; (b) 5HS woven layout.
Mentions: Figure 6 presents the studied samples and the layout of five harness satin woven of carbon fibers. The plates were subjected to impacts with energies of 2, 4, 6, 8, 10 and 12 J. The composite plates exhibit electric properties that depend on the type of carbon fibers and on their volume fraction in the material, having the transverse electric conductivity between 10 S/m and 100 S/m and longitudinal conductivity ranging between 5 × 103 S/m and 5 × 104 S/m. The samples were impacted using a FRACTOVIS PLUS 9350-CEAST instrument (Instron, Norwood, MA, USA) with a hemispherical bumper head having 20 mm diameter and 2.045 kg weight, in order to induce delaminations. The impact data were recorded with a DAS16000 acquisition system (Instron) with a sampling frequency of 1 MHz [59]. For higher energy impacts, local deformations result in delamination propagation, deviation and/or breaking of the carbon fibers. In both cases, the modification of local conductivity allows the damage detection using electromagnetic methods [60]. Typical records of force vs. time during impact can give information about the CFRP status (delaminated or not) [61]. Thus, only plates that show delamination were used in the study, meaning the plates impacted with 6 J, 8 J, 10 J and 12 J.

Bottom Line: These structures can serve as electromagnetic flux concentrators in the radiofrequency range.The evaluation method is based on the appearance of evanescent modes in the space between carbon fibers when the sample is excited with a transversal magnetic along z axis (TMz) polarized electromagnetic field.The flaws can be localized with spatial resolution better than λ/2000.

View Article: PubMed Central - PubMed

Affiliation: Nondestructive Testing Department, National Institute of R&D for Technical Physics, 47 D. Mangeron Blvd, 700050 Iasi, Romania. asavin@phys-iasi.ro.

ABSTRACT
This paper proposes the study and implementation of a sensor with a metamaterial (MM) lens in electromagnetic nondestructive evaluation (eNDE). Thus, the use of a new type of MM, named Conical Swiss Rolls (CSR) has been proposed. These structures can serve as electromagnetic flux concentrators in the radiofrequency range. As a direct application, plates of composite materials with carbon fibers woven as reinforcement and polyphenylene sulphide as matrix with delaminations due to low energy impacts were examined. The evaluation method is based on the appearance of evanescent modes in the space between carbon fibers when the sample is excited with a transversal magnetic along z axis (TMz) polarized electromagnetic field. The MM lens allows the transmission and intensification of evanescent waves. The characteristics of carbon fibers woven structure became visible and delaminations are clearly emphasized. The flaws can be localized with spatial resolution better than λ/2000.

No MeSH data available.


Related in: MedlinePlus