Application of Unidirectional Carbon-Fiber-Reinforced-Polymer Laminas in Circuit-Analog Absorbers

Riley, Elliot J.; Lenzing, Erik H.; Narayanan, Ram M.

doi:10.1109/temc.2017.2781142

Cited by 17 publications

(3 citation statements)

References 27 publications

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“…Measurements indicate that at 12 GHz, the complex dielectric constant of aluminum hydroxide is about 2.5 [31] while that of CFRP is about 10 10 j  when the electric field is oriented perpendicular to the fiber direction (to achieve high signal penetration) [32]. Thus, there is adequate dielectric constant between the CFRP material and the aluminum hydroxide to appear as differences in the image.…”

Section: Chemistry Of Galvanic Corrosionmentioning

confidence: 99%

Microwave Nondestructive Testing of Galvanic Corrosion and Impact Damage in Carbon Fiber Reinforced Polymer Composites

Narayanan¹

2018

IJMA

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Advanced composite materials are being used extensively in many commercial and military aircraft and rotorcraft due to their superior stiffness and high strength-to-weight ratio. These composites are subjected to unexpected environmentally assisted damages. This work covers exploration and the methodology of detection of two such types of damages -galvanic corrosion and impact damages, at the earliest stages of development.When aluminum alloy and CFRP are coupled together, the structural strength of the aircraft is unparalleled, but this comes at a price, namely galvanic corrosion (GC). Previous experimental results have shown that when CFRP composite materials are joined with high strength aluminum alloys, galvanic corrosion occurs at the material interfaces, and the aluminum is in great danger of corroding.Composite materials used in aircraft are often subjected to unexpected environmental impact loads at high speeds, such as bird strikes and hailstone impacts. The damages developed in such cases is primarily in the form of delamination and matrix cracking, known as barely visible impact damage (BVID), since they are not easily observable by the naked eye. Prediction and detection of such environmental damages, which can occur in the service life of the aircraft, are of paramount importance in the aerospace industry.This work utilizes the software BEASY for the prediction of galvanic corrosion and utilizes ABAQUS Explicit for modeling the bird impact damage and the hailstone impact damage by using the smoothed particle hydrodynamics (SPH) modeling method. This work also proposes a non-invasive microwave nondestructive testing (NDT) technique that can be employed as a detection methodology to detect the aforementioned types of environmentally assisted damages. Radar signals operating at a set frequency range can be used to detect the aforementioned environmentally assisted damages to obtain high-resolution 2D images of such damages.

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Section: Chemistry Of Galvanic Corrosionmentioning

confidence: 99%

Microwave Nondestructive Testing of Galvanic Corrosion and Impact Damage in Carbon Fiber Reinforced Polymer Composites

Narayanan¹

2018

IJMA

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“…CAAs in this work take the form of CFRP-foam-aluminum sandwich structures and are designed to absorb incident energy at X-band frequencies (between 8 and 12.4 GHz). Following fabrication techniques presented and discussed in [13][14][15], ten, single-ply, unidirectional CFRP CAAs were fabricated using 305 g/m 2 areal-weight CFRP. The ten absorbers were introduced inside the salt water fog chamber simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Salt Water Exposure Effects on Single-Layer, Unidirectional Carbon-Fiber Reinforced Polymer Circuit Analog Absorbers

O'Donnell¹,

Narayanan²

2021

PIER B

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This paper explores the effects of extended exposure to salt water fog on the microwave absorption properties of unidirectional carbon-fiber reinforced polymer (CFRP) circuit analog absorbers (CAA). Single-layer CFRP CAAs were fabricated using a wet-layup technique and were then subjected to a controlled salt water fog chamber following B117 standards. A total of ten samples using 305 g/m 2 areal-weight unidirectional CFRP were fabricated. Three samples were withdrawn from the salt water environment at ten-day intervals and tested, with the final samples being withdrawn after 30 days. The mass of each sample was measured immediately after removal to measure mass-accumulation and after a five-day interval to measure mass-loss. A free space microwave reflection measurement system was implemented to track and quantify changes to the absorption capabilities of the CAA. A physicallybased electromagnetic model was developed to characterize the changes caused by salt water absorption, and good agreement was observed with measured data.

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“…The bandwidth of absorption can be improved if resistive FSS is employed instead of homogenous resistive sheets. This kind of absorber is called circuit analogue absorber (CAA) . The design procedure of them is summarized in tree steps …”

Section: Introductionmentioning

confidence: 99%

Novel synthesis formulas to design square patch frequency selective surface absorber based on equivalent circuit model

Firouzfar

Afsahi

Orouji

2019

Int J RF Microw Comput Aided Eng

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A new procedure is presented to design electromagnetic absorbers based on resistive square patch frequency selective surface (FSS) over grounded dielectric. The periodicity (p) and the distance between two adjacent squares in the lattice (w) are two unknowns to be solved, given the thickness and permittivity of the substrate, surface impedance of the square patches and the desired reflectivity in some specified frequency. Equivalent circuit model and transmission line method are employed here. Previously reported analysis formulas to calculate the square patch FSS admittance are exploited and novel synthesis formulas are extracted based of them. The final synthesis equations to calculate p and w are presented in term of polynomials. Usually an absorber is supposed to have a maximum reflectivity r in a frequency band [f 1 , f 2 ]. The (p, w) pairs for reflectivity less than r in f 1 , define an area in p-w plane. The intersection of the so-called area with the similar one defined by f 2 specifies all possible (p, w) pairs. Finally the results are tested and verified by the commercial full wave simulator Ansys-HFSS as well as some experimental design. There is a good agreement between the expected results with the full wave analysis and practical test. K E Y W O R D S synthesis formulas, equivalent circuit, square patch FSS absorbers

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Application of Unidirectional Carbon-Fiber-Reinforced-Polymer Laminas in Circuit-Analog Absorbers

Cited by 17 publications

References 27 publications

Microwave Nondestructive Testing of Galvanic Corrosion and Impact Damage in Carbon Fiber Reinforced Polymer Composites

Microwave Nondestructive Testing of Galvanic Corrosion and Impact Damage in Carbon Fiber Reinforced Polymer Composites

Salt Water Exposure Effects on Single-Layer, Unidirectional Carbon-Fiber Reinforced Polymer Circuit Analog Absorbers

Novel synthesis formulas to design square patch frequency selective surface absorber based on equivalent circuit model

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