Abstract
Single-resonance-based radio frequency (RF) resonators cannot detect multiple cracks simultaneously nor localize the position of a crack. To address these drawbacks, we propose a complementary split-ring resonator (CSRR)-loaded array. In this array, there are four channels and each channel consists of three CSRRs, forming a 4 × 3 sensing array that is developed in the ground plane of a microstrip line using a low-cost FR4 substrate. A voltage-controlled oscillator (VCO) generates three discrete frequencies: 1.88 GHz, 2.60 GHz, and 3.61 GHz to each channel, which is sequentially selected using a single-pole four-throw (SP4T) switch. The transmitted RF signals are converted into the DC voltage levels and are interpreted by a microcontroller. Aluminum sheets with cracks embedded in the surface are used to demonstrate the detection of cracks of various shapes, sizes and locations/orientations (horizontal, diagonal, and vertical) with simulations and measurements. The detection of the minimum detectable crack (W c × L c × D c = 1 mm × 10 mm × 0.1 mm) is experimentally verified. Full-length longer cracks (L c = 100 mm) are also detected using our proposed detection system with the SP4T switch in addition to our proposed algorithm that scans the CSRRs of each selected channel.
Highlights
Structural health monitoring (SHM) is a diverse field that includes the continuous monitoring of structures and their constituting parts, non-destructive diagnoses of anomaly states, and the prognosis of future implications for preventive measures
Radiofrequency (RF) technology includes sensing devices that have gained much attention in research owing to attractive features such as low cost, simpler fabrication, and smaller sizes compared with non-RF crack sensors
We address these serious limitations of single resonance based RF crack sensors
Summary
Structural health monitoring (SHM) is a diverse field that includes the continuous monitoring of structures and their constituting parts, non-destructive diagnoses of anomaly states, and the prognosis of future implications for preventive measures. A variety of RF resonators have been proposed to detect cracks on metallic surfaces. In [3], an X-band frequency selective surface consisting of several crossshaped unit cells realized on a polyimide film is proposed to detect metallic cracks in large-area structures. In [4], a CSRR is loaded on the ground plane of the substrate integrated waveguide (SIW) structure to detect a 1-mmwide crack in a 5-mm thick aluminum (Al) sheet. In [5] a CSRR is patterned on the ground plane of a microstrip line to detect cracks in an aluminum sheet. Where εo, εr, A, s, Leff, Ceff, and fr represent the free-space permittivity, relative permittivity, area, split-gap of the CSRR, effective inductance, effective capacitance, and resonance frequency of the CSRR, respectively [7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
