Microwave and Millimeter Wave Nondestructive Testing and Evaluation

Kharkovsky, Sergey; Zoughi, R.

doi:10.1007/978-3-319-26553-7_59

Cited by 8 publications

(1 citation statement)

References 94 publications

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“…Furthermore, we include recently developed, more efficient, non-contact techniques using broadband US excitation and detection. By setting them side-by-side with the conventional and established methods, 14,15 their potentials can be evaluated. Additionally, we compare various radiographic methods on the same example.…”

Section: Introductionmentioning

confidence: 99%

Qualitative comparison of non-destructive methods for inspection of carbon fiber-reinforced polymer laminates

Rus

Gustschin

Mooshofer

et al. 2020

Journal of Composite Materials

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In the rapidly expanding composite industry, novel inspection methods have been developed in recent years. Particularly promising for air-coupled testing are cellular polypropylene transducers which offer better impedance matching to air than piezoelectric transducers. Furthermore, broadband transmitters (laser-induced ultrasound and thermoacoustic emitters) and receivers (optical microphones) have opened a completely new chapter for advanced contact-free ultrasound inspection. X-ray dark-field radiography offers a different approach to detect porosity and microcracks, employing small angle X-ray scattering. These innovative ultrasonic and radiographic alternatives were evaluated in comparison with well-established inspection techniques. We applied thirteen different non-destructive methods to inspect the same specimen (a carbon fiber-reinforced polymer laminate with induced impact damage): air-coupled ultrasound testing (using piezoelectric transducers, broadband optical microphones, cellular polypropylene transducers, and a thermoacoustic emitter), laser-induced ultrasound testing, ultrasonic immersion testing, phased array ultrasonic testing, optically excited lock-in thermography, and X-ray radiography (projectional absorption and dark-field, tomosynthesis, and micro-computed tomography). The inspection methods were qualitatively characterized by comparing the scan results. The conclusions are advantageous for a decision on the optimal method for certain testing constraints.

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Section: Introductionmentioning

confidence: 99%

Qualitative comparison of non-destructive methods for inspection of carbon fiber-reinforced polymer laminates

Rus

Gustschin

Mooshofer

et al. 2020

Journal of Composite Materials

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Unconventional Nonequilibrium Phase Stabilization in FeNi Alloy Examined by Positron Annihilation Spectroscopy

Billgates,

Jacob,

Sellaiyan

et al. 2023

Physica Status Solidi (b)

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The equilibrium FeNi alloy prefers face centered cubic (fcc) phase whereas the formation of metastable phases through certain low‐temperature synthesis methods is obscure. FeNi alloy exhibiting nonequilibrium body centered cubic (bcc) structure beyond 5 at% Ni is obtained through chemical reduction at 453 K with noticeable lattice shrinkage. Positron lifetime analysis and Doppler broadening spectroscopy are employed to probe the correlation between defects and phase stability. The mean lifetime of the chemically synthesized alloys is larger than 300 ps, implying an average of 7‐vacancy cluster. The modified two‐state trapping model reveals defect concentration in the range of , on par with irradiated alloys. Significant deviation in the high‐momentum component between the bulk and chemically synthesized samples is correlated to the changes in 3d electrons. The Fe and FeNi alloy uncover significant contraction in d‐band of Fe which facilitates bcc phase stabilization above 5 at% Ni through cluster vacancy formation.

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High Resolution and Polarization Independent Microwave Near-Field Imaging Using Planar Resonator Probes

et al. 2020

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Various near-field microwave imaging probes were developed previously for nondestructive testing of material structures. Sensitivity and resolution are key parameters for quantifying the efficacy of a given imaging probe. For polarized targets like cracks, the sensitivity of conventional aperture probes depends on the relative orientation between the probe's electric-field vector and the target. In practice, target orientation is typically unknown. Furthermore, the imaging resolution of conventional aperture probes is limited to aperture dimensions. Obtaining imaging resolution in the order of few millimeters using conventional aperture probes requires operation at high frequencies, (above 30 GHz). In contrast, planar probes consisting of loops loaded with spiral resonators could provide resolution in the order of few millimeters while working at relatively low frequencies (below 1 GHz). Unlike conventional aperture probes, the radiated near-fields of these probes are characterized by two significant components oriented along orthogonal axes. Therefore, the probe intrinsically provides a polarization-independent response. In this paper, the near-field imaging resolution of the planar resonator probe is further enhanced, and its polarizationindependent response is demonstrated for the first time. The response of three planar probe prototypes of different dimensions is analyzed based on numerical simulation and experimental results. The performance of the probes is extensively evaluated by acquiring line-scans and 2D-images of metal and dielectric samples. The near-field images of the metal sample obtained using the planar probes working below 1 GHz are compared to the images obtained using aperture probes working at 24 GHz, 33 GHz, and 70 GHz. Furthermore, the probe imaging performance for a polarized target (i.e., narrow cuts) is compared to dualpolarized circular probe working at 24 GHz and open-ended coaxial probe working at 10 GHz. Overall, the proposed probe yielded more than twofold increase in the image signal-to-noise ratio (SNR) compared to all the probes utilized herein. INDEX TERMS non-destructive testing, microwave imaging, planar probe, near-field, polarization, spiral resonator This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.

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Microwave and Millimeter Wave Nondestructive Testing and Evaluation

Cited by 8 publications

References 94 publications

Qualitative comparison of non-destructive methods for inspection of carbon fiber-reinforced polymer laminates

Qualitative comparison of non-destructive methods for inspection of carbon fiber-reinforced polymer laminates

Unconventional Nonequilibrium Phase Stabilization in FeNi Alloy Examined by Positron Annihilation Spectroscopy

High Resolution and Polarization Independent Microwave Near-Field Imaging Using Planar Resonator Probes

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