{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,16]],"date-time":"2026-02-16T18:35:28Z","timestamp":1771266928611,"version":"3.50.1"},"reference-count":40,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2020,10,29]],"date-time":"2020-10-29T00:00:00Z","timestamp":1603929600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100008530","name":"European Regional Development Fund","doi-asserted-by":"publisher","award":["PID2019-109175GB-C22"],"award-info":[{"award-number":["PID2019-109175GB-C22"]}],"id":[{"id":"10.13039\/501100008530","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100010198","name":"Ministerio de Econom\u00eda, Industria y Competitividad, Gobierno de Espa\u00f1a","doi-asserted-by":"publisher","award":["PID2019-109175GB-C22"],"award-info":[{"award-number":["PID2019-109175GB-C22"]}],"id":[{"id":"10.13039\/501100010198","id-type":"DOI","asserted-by":"publisher"}]},{"name":"US Army Research, Development, and Engineering Command (RDECOM)","award":["W911NF-16-1-0563"],"award-info":[{"award-number":["W911NF-16-1-0563"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this work, we numerically investigate the diffraction management of longitudinal elastic waves propagating in a two-dimensional metallic phononic crystal. We demonstrate that this structure acts as an \u201cultrasonic lens\u201d, providing self-collimation or focusing effect at a certain distance from the crystal output. We implement this directional propagation in the design of a coupling device capable to control the directivity or focusing of ultrasonic waves propagation inside a target object. These effects are robust over a broad frequency band and are preserved in the propagation through a coupling gel between the \u201cultrasonic lens\u201d and the solid target. These results may find interesting industrial and medical applications, where the localization of the ultrasonic waves may be required at certain positions embedded in the object under study. An application example for non-destructive testing with improved results, after using the ultrasonic lens, is discussed as a proof of concept for the novelty and applicability of our numerical simulation study.<\/jats:p>","DOI":"10.3390\/s20216148","type":"journal-article","created":{"date-parts":[[2020,10,29]],"date-time":"2020-10-29T21:21:00Z","timestamp":1604006460000},"page":"6148","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Directional Ultrasound Source for Solid Materials Inspection: Diffraction Management in a Metallic Phononic Crystal"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2553-8205","authenticated-orcid":false,"given":"Hossam","family":"Selim","sequence":"first","affiliation":[{"name":"Physics Department, Universitat Polit\u00e8cnica de Catalunya, Rambla Sant Nebridi 22, 08222 Terrassa, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3537-9658","authenticated-orcid":false,"given":"Rub\u00e9n","family":"Pic\u00f3","sequence":"additional","affiliation":[{"name":"Instituto de Investigaci\u00f3n Para la Gesti\u00f3n Integrada de Zonas Costeras, Universitat Polit\u00e8cnica de Val\u00e8ncia, Paranimf 1, Grao de Gandia, 46730 Val\u00e8ncia, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jose","family":"Trull","sequence":"additional","affiliation":[{"name":"Physics Department, Universitat Polit\u00e8cnica de Catalunya, Rambla Sant Nebridi 22, 08222 Terrassa, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9282-838X","authenticated-orcid":false,"given":"Miguel Delgado","family":"Prieto","sequence":"additional","affiliation":[{"name":"Electronic Engineering Department, Universitat Polit\u00e8cnica de Catalunya, Rambla Sant Nebridi 22, 08222 Terrassa, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Crina","family":"Cojocaru","sequence":"additional","affiliation":[{"name":"Physics Department, Universitat Polit\u00e8cnica de Catalunya, Rambla Sant Nebridi 22, 08222 Terrassa, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,10,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Sternberg, R.L. 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