{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T04:33:23Z","timestamp":1774326803847,"version":"3.50.1"},"reference-count":22,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2025,12,6]],"date-time":"2025-12-06T00:00:00Z","timestamp":1764979200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Scientific Research Projects of China Academy of Railway Sciences","award":["2024YJ034"],"award-info":[{"award-number":["2024YJ034"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The problem of poor coupling and wheel breakage is a critical issue in the rapid inspection of rails using contact piezoelectric ultrasonic technology for trolleys and vehicles. To overcome this shortcoming, a non-contact unidirectional Shear Vertical Wave EMAT (USV-EMAT) for rapid rail flaw detection with a larger emission angle is proposed and optimized. First, the core characteristics of the USV-EMAT and the Unidirectional Line-Focusing Shear Vertical Wave EMAT (ULSV-EMAT) are compared and analyzed, including emission angle, directivity, intensity, and detection scan distance. The results confirmed that the USV-EMAT is more suitable for rapid rail flaw detection. Secondly, the orthogonal experimental analysis method was used to optimize the structural parameters of the probe. This study systematically identified the key factors influencing the directivity and intensity of acoustic waves excited by the probe, as well as the detection blind zones. Finally, the structural parameters of the integrated 37\u00b0 USV-EMAT probe were determined by comparing and analyzing the received signal characteristics of the transmit\u2013receive racetrack coil and the self-transmitting\u2013receiving meander coil. The results show that the optimized probe achieves a 14.3 dB SNR for detecting a 5 mm diameter, 50 mm deep transverse hole in the rail, and a 14.0 dB SNR for a 3 mm diameter, 25 mm long, 50 mm deep flat-bottomed hole. Additionally, this study reveals that as the burial depth of the transverse holes increases, the detection scan distance for such defects exhibits an \u201cN\u201d-shaped trend, with the minimum occurring at a depth of 90 mm.<\/jats:p>","DOI":"10.3390\/s25247424","type":"journal-article","created":{"date-parts":[[2025,12,8]],"date-time":"2025-12-08T15:30:07Z","timestamp":1765207807000},"page":"7424","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Study and Optimal Design of the Integrated 37\u00b0 Unidirectional SV-EMAT for Rapid Rail Flaw Detection"],"prefix":"10.3390","volume":"25","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0539-9159","authenticated-orcid":false,"given":"Wei","family":"Yuan","sequence":"first","affiliation":[{"name":"Infrastructure Inspection Research Institute, China Academy of Railway Sciences Corporation Limited, Beijing 100081, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,6]]},"reference":[{"key":"ref_1","first-page":"681","article-title":"Investigation of the glued insulated rail joints applied to CWR tracks","volume":"19","author":"Fischer","year":"2021","journal-title":"Facta Univ. 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