{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,15]],"date-time":"2026-04-15T16:47:18Z","timestamp":1776271638890,"version":"3.50.1"},"reference-count":44,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2024,11,17]],"date-time":"2024-11-17T00:00:00Z","timestamp":1731801600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Portuguese Foundation for Science and Technology (FCT)","doi-asserted-by":"publisher","award":["2020.09991.BD"],"award-info":[{"award-number":["2020.09991.BD"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Portuguese Foundation for Science and Technology (FCT)","doi-asserted-by":"publisher","award":["CEECIND\/03276\/2018"],"award-info":[{"award-number":["CEECIND\/03276\/2018"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Three-dimensional printing is widely becoming prevalent in various industries, including the automotive sector. As this technology advances, critical structures subjected to impact loads may also be produced using additive manufacturing. A key parameter in this technique is the infill density of the printed geometry, which directly affects mechanical properties such as strength, stiffness, and ductility. Functionally graded layouts present themselves as one of the best techniques to design effective impact attenuators. The present work combines these techniques and parameters to evaluate the behaviour of geometrically graded impact attenuators produced through additive manufacturing, with different infill densities for polylactic acid (PLA) and polycarbonate (PC) materials. The results obtained show an increase in the mechanical strength for both materials and all the infill densities when compared to reference quasi-static results.<\/jats:p>","DOI":"10.3390\/polym16223193","type":"journal-article","created":{"date-parts":[[2024,11,18]],"date-time":"2024-11-18T07:45:27Z","timestamp":1731915927000},"page":"3193","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Effect of the Infill Density on 3D-Printed Geometrically Graded Impact Attenuators"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6135-3665","authenticated-orcid":false,"given":"Mateus Q.","family":"dos Reis","sequence":"first","affiliation":[{"name":"Departamento de Engenharia Mec\u00e2nica e Gest\u00e3o Industrial, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1933-0865","authenticated-orcid":false,"given":"Ricardo J. C.","family":"Carbas","sequence":"additional","affiliation":[{"name":"Departamento de Engenharia Mec\u00e2nica e Gest\u00e3o Industrial, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto, Portugal"},{"name":"Instituto de Ci\u00eancia e Inova\u00e7\u00e3o em Engenharia Mec\u00e2nica e Engenharia Industrial (INEGI), 4200-465 Porto, Portugal"}]},{"given":"Eduardo A. S.","family":"Marques","sequence":"additional","affiliation":[{"name":"Departamento de Engenharia Mec\u00e2nica e Gest\u00e3o Industrial, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3272-4591","authenticated-orcid":false,"given":"Lucas F. M.","family":"da Silva","sequence":"additional","affiliation":[{"name":"Departamento de Engenharia Mec\u00e2nica e Gest\u00e3o Industrial, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2024,11,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Gibson, I., Rosen, D., and Stucker, B. (2015). Direct Digital Manufacturing. Additive Manufacturing Technologies: 3D Printing, Rapid Prototyping, and Direct Digital Manufacturing, Springer.","DOI":"10.1007\/978-1-4939-2113-3"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"172","DOI":"10.1016\/j.compositesb.2018.02.012","article-title":"Additive Manufacturing (3D Printing): A Review of Materials, Methods, Applications and Challenges","volume":"143","author":"Ngo","year":"2018","journal-title":"Compos. 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