Surface crack detection is a crucial task in petrochemical and aerospace industry. The development of precise, flexible and reliable sensors for structural health monitoring (SHM) system is highly recommended to detect material imperfections and monitor their progress. Effective (SHM) system requires placement of large number of sensors on flexible sheet. This paper presents high sensitivity miniaturized microwave-based designs of surface crack sensor topologies using asymmetric complementary split ring resonators (CSRR). The presented designs improve the sensors’ probability of detection (POD) by at least 50% compared to recently proposed ones. Moreover, sensors’ designs are simple with flexible design parameters and a wide dynamic range of the sensing-related frequency which make them suitable for customized designs based on recommended acceptance criteria. The sensors’ performance has been verified using the full-wave numerical simulation package ANSYS HFSS. Unlike previously proposed metasurface based crack sensors, each of the presented sensors is capable of detecting parallel and/or perpendicularly oriented cracks within its close proximity. This property eliminates the need for multiple orthogonal scanning and fulfill effective (SHM) system requirement. The main characteristic feature of the proposed sensors’ response, is the excitation of new resonance modes close to the reference case resonance modes. This feature supersedes the usual detection technique sensitivity which uses single mode frequency shift alone as an indicator of crack presence.

DOI: https://doi.org/10.32548/RS.2018.015

Related Publications