{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,4]],"date-time":"2026-07-04T02:28:32Z","timestamp":1783132112147,"version":"3.54.6"},"reference-count":38,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2022,12,22]],"date-time":"2022-12-22T00:00:00Z","timestamp":1671667200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["2021YFC3001802"],"award-info":[{"award-number":["2021YFC3001802"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["12025403"],"award-info":[{"award-number":["12025403"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["U1930202"],"award-info":[{"award-number":["U1930202"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["51835003"],"award-info":[{"award-number":["51835003"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["12174102"],"award-info":[{"award-number":["12174102"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["12004114"],"award-info":[{"award-number":["12004114"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["2021YFC3001802"],"award-info":[{"award-number":["2021YFC3001802"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["12025403"],"award-info":[{"award-number":["12025403"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["U1930202"],"award-info":[{"award-number":["U1930202"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["51835003"],"award-info":[{"award-number":["51835003"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["12174102"],"award-info":[{"award-number":["12174102"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["12004114"],"award-info":[{"award-number":["12004114"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This article proposes an electromagnetic acoustic transducer (EMAT) for selectively improving the purity and amplitude of ultrasonic Lamb waves in non-ferromagnetic plates. The developed EMAT consists of a racetrack coil and a group of periodic permanent magnets (PPMs). Two-dimensional finite element simulations and experiments are implemented to analyze the working mechanism and performance of the PPM EMAT. Thanks to the specific design, the eddy currents increase with increasing wire density and the directions of the magnetic fields and Lorentz forces alternate according to the polarities of the magnet units. Wires laid uniformly beneath the magnets, and the gaps between adjacent magnets generate tangential and normal Lorentz forces, resulting in-plane (IP) and out-of-plane (OP) displacements, respectively. The constructive interference occurs when the wavelength of the generated Lamb wave is twice the spacing of the magnets, leading to large amplitudes of the targeted ultrasonic Lamb waves. Therefore, the PPM EMAT is capable of generating pure symmetric or antisymmetric mode Lamb waves at respective frequencies. The results prove that the developed PPM EMAT can generate pure either S0 or A0 mode Lamb waves at respective frequencies. The increase in wire width and wire density further increases the signal amplitudes. Compared with the case of conventional meander-line-coil (MLC) EMAT, the amplitudes of the A0 and S0 mode Lamb waves of our PPM EMAT are increased to 880% and 328%, respectively.<\/jats:p>","DOI":"10.3390\/s23010096","type":"journal-article","created":{"date-parts":[[2022,12,23]],"date-time":"2022-12-23T03:55:21Z","timestamp":1671767721000},"page":"96","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["A Lorentz Force EMAT Design with Racetrack Coil and Periodic Permanent Magnets for Selective Enhancement of Ultrasonic Lamb Wave Generation"],"prefix":"10.3390","volume":"23","author":[{"given":"Xinfeng","family":"Guo","sequence":"first","affiliation":[{"name":"Shanghai Key Laboratory of Intelligent Sensing and Detection Technology, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1347-8129","authenticated-orcid":false,"given":"Wujun","family":"Zhu","sequence":"additional","affiliation":[{"name":"Shanghai Key Laboratory of Intelligent Sensing and Detection Technology, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xunlin","family":"Qiu","sequence":"additional","affiliation":[{"name":"Shanghai Key Laboratory of Intelligent Sensing and Detection Technology, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yanxun","family":"Xiang","sequence":"additional","affiliation":[{"name":"Shanghai Key Laboratory of Intelligent Sensing and Detection Technology, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,12,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"102313","DOI":"10.1016\/j.ndteint.2020.102313","article-title":"Quantifying the lowest remnant thickness using a novel broadband wavelength and frequency EMAT utilizing the cut-off property of guided waves","volume":"116","author":"Suresh","year":"2020","journal-title":"NDT&E Int."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"124","DOI":"10.1016\/j.ndteint.2019.04.009","article-title":"Obliquely incident EMAT for high-order Lamb wave mode generation based on inclined static magnetic field","volume":"104","author":"Liu","year":"2019","journal-title":"NDT&E Int."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1877","DOI":"10.1088\/0266-5611\/20\/6\/012","article-title":"Automatic multi-mode Lamb wave arrival time extraction for improved tomographic reconstruction","volume":"20","author":"Hou","year":"2004","journal-title":"Inverse Probl."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1016\/j.ndteint.2015.05.005","article-title":"Weld defect detection using PPM EMAT generated shear horizontal ultrasound","volume":"74","author":"Petcher","year":"2015","journal-title":"NDT&E Int."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1165","DOI":"10.1109\/TUFFC.2013.2679","article-title":"Mode selection for corrosion detection in pipes and vessels via guided wave tomography","volume":"60","author":"Huthwaite","year":"2013","journal-title":"IEEE Trans. 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