{"id":61669,"date":"2023-12-08T16:41:58","date_gmt":"2023-12-08T14:41:58","guid":{"rendered":"https:\/\/www.iemn.fr\/articles-temporaires-anglais\/les-metamateriaux-mecaniques-et-acoustiques-et-le-concept-darchitecture-de-la-cellule-unitaire-2.html"},"modified":"2024-01-19T16:10:56","modified_gmt":"2024-01-19T14:10:56","slug":"metamaterials-mechanical-and-acoustic-and-the-concept-of-unit-cell-architecture","status":"publish","type":"post","link":"https:\/\/www.iemn.fr\/en\/newsletter\/metamaterials-mechanical-and-acoustic-and-the-concept-of-unit-cell-architecture.html","title":{"rendered":"Metamaterials (mechanical and acoustic) and the concept of unit cell architecture"},"content":{"rendered":"<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-sx3vs0-44b2a8ab14b4051c54bfc3098d7228b7\">\n.flex_column.av-sx3vs0-44b2a8ab14b4051c54bfc3098d7228b7{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-sx3vs0-44b2a8ab14b4051c54bfc3098d7228b7 av_one_full  avia-builder-el-0  el_before_av_one_half  avia-builder-el-first  first flex_column_div av-zero-column-padding'     ><p><section  class='av_textblock_section av-lq2h9d9t-12a3a08f2f507a08a759475a77dc6679'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/metamateriaux5.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-62291 size-full\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/metamateriaux5.jpg\" alt=\"\" width=\"1000\" height=\"191\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/metamateriaux5.jpg 1000w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/metamateriaux5-300x57.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/metamateriaux5-768x147.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/metamateriaux5-18x3.jpg 18w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/metamateriaux5-705x135.jpg 705w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\" \/><\/a><\/p>\n<\/div><\/section><br \/>\n<section  class='av_textblock_section av-lq2gsmqj-1502b9fe0245d0adffd65f475a0b3bb2'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h1 style=\"text-align: center;\"><span style=\"color: #097482;\">The \u00ab\u00a0role of architecture\u00a0\u00bb in (mechanical and acoustic) metamaterials: Mother Nature had already thought of it!<\/span><\/h1>\n<\/div><\/section><br \/>\n<section  class='av_textblock_section av-lq3g1xs9-e2bbdeb2dc2818922a500daf80dbd7b8'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p style=\"font-weight: 400;\">Although no universally accepted definition of metamaterials is currently available in mechanics and acoustics, it is commonly accepted that \u00ab\u00a0geometry\u00a0\u00bb plays a fundamental role in determining their static and dynamic behavior. While in the early 2000s, the shape of the metamaterial unit cells was rather canonical (matrix with circular or square inclusions, etc.), over time, increasingly complex geometries have been explored thanks to the improved calculation power of computers and the evolution of manufacturing technologies.<\/p>\n<p style=\"font-weight: 400;\"><span style=\"color: #097482;\"><span style=\"color: #000000;\">In this context,<\/span> Nature, thanks to millions of years of evolution, is a great master of \u00ab\u00a0material architecture\u00a0\u00bb to obtain specific advanced properties and geometries focused on precise functionalities. Taking inspiration from hierarchical or fractal architectures, typical of most biological systems, we show that reproducing this structural enrichment at the mesoscale of metamaterials induces behaviors of great richness, opening new perspectives for elastic wave control based on the simultaneous activation of various wave attenuation mechanisms.<\/span><\/p>\n<\/div><\/section><\/p><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-15dykqo-690853588527c9e0b6608de3de826593\">\n.flex_column.av-15dykqo-690853588527c9e0b6608de3de826593{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-15dykqo-690853588527c9e0b6608de3de826593 av_one_half  avia-builder-el-4  el_after_av_one_full  el_before_av_one_half  first flex_column_div av-zero-column-padding  column-top-margin'     ><section  class='av_textblock_section av-lq2hhk08-2b698380024dc00bff08dc43dac32f95'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h5>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-qawvnx-eb0fa84a59d44b41dd8d2a500ef04acb\">\n.av_font_icon.av-qawvnx-eb0fa84a59d44b41dd8d2a500ef04acb{\ncolor:#097482;\nborder-color:#097482;\n}\n.av_font_icon.av-qawvnx-eb0fa84a59d44b41dd8d2a500ef04acb .av-icon-char{\nfont-size:20px;\nline-height:20px;\n}\n<\/style>\n<span  class='av_font_icon av-qawvnx-eb0fa84a59d44b41dd8d2a500ef04acb avia_animate_when_visible av-icon-style- avia-icon-pos-left avia-icon-animate'><span class='av-icon-char' aria-hidden='true' data-av_icon='\ue881' data-av_iconfont='entypo-fontello' ><\/span><\/span><\/h5>\n<h4><span style=\"color: #097482;\">Metamaterials (mechanical and acoustic) and the concept of unit cell architecture<\/span><\/h4>\n<p><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/metamateriaux4.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-62288 alignleft\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/metamateriaux4-300x113.jpg\" alt=\"\" width=\"300\" height=\"113\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/metamateriaux4-300x113.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/metamateriaux4-18x7.jpg 18w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/metamateriaux4.jpg 400w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>Although no universally accepted definition of metamaterials is currently available in mechanics and acoustics, the scientific community tends to identify them as \u00ab\u00a0composites with a periodic or quasi-periodic architecture, designed to produce an unconventional (static or dynamic) response to specific solicitations\u00a0\u00bb.<br \/>\nThe \u00ab\u00a0geometry\u00a0\u00bb therefore plays a fundamental role in determining the properties of metamaterials.<br \/>\nFor example, in dynamics, at the same filling fraction(1), the shape (cylindrical, squared, etc.) of the inclusions (or voids) and their distribution in the unit cell (centered, at the edges, etc.) can lead in the dispersion diagram to the opening of frequency bandgaps (frequency regions where the propagation of waves is strongly attenuated) or to curves with negative slope. This allows to attain unconventional behaviors such as negative refraction, topological protection, perfect absorption, etc.<\/p>\n<\/div><\/section><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-wns4tc-1db3423f7cd08c59a5a437f03f40996e\">\n.flex_column.av-wns4tc-1db3423f7cd08c59a5a437f03f40996e{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-wns4tc-1db3423f7cd08c59a5a437f03f40996e av_one_half  avia-builder-el-7  el_after_av_one_half  el_before_av_one_full  flex_column_div av-zero-column-padding  column-top-margin'     ><section  class='av_textblock_section av-lq2hhk08-2b698380024dc00bff08dc43dac32f95'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p style=\"font-weight: 400;\">Similarly, when local resonance effects are the main responsible for the overall behavior of the metamaterial, the design of the resonators becomes essential. In this sense, it could be said that <strong><span style=\"color: #097482;\"><em>metamaterials themselves carry the concept of <u>architecture<\/u><\/em>.<\/span><\/strong><\/p>\n<p style=\"font-weight: 400;\">While, in the early 2000s, the geometries explored for the unit cells were rather canonical (matrix with circular or square holes, plates with pillars, etc.), increasingly complex architectures have since been explored. This has been made possible by (i) the increasing calculation power of computers, and (ii) the evolution of manufacturing technologies. Two important examples are 3D printing, producing complex designs at reasonable prices, and (photo-)lithography, which offers unprecedented resolution over several length scales.<\/p>\n<p><em>(1) Ratio of the volumes making up the matrix and the inclusion in a unit cell.<\/em><\/p>\n<\/div><\/section><\/div><\/p>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-sx3vs0-44b2a8ab14b4051c54bfc3098d7228b7\">\n.flex_column.av-sx3vs0-44b2a8ab14b4051c54bfc3098d7228b7{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-sx3vs0-44b2a8ab14b4051c54bfc3098d7228b7 av_one_full  avia-builder-el-9  el_after_av_one_half  el_before_av_one_half  first flex_column_div av-zero-column-padding  column-top-margin'     ><section  class='av_textblock_section av-lq2hhk08-2b698380024dc00bff08dc43dac32f95'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p><span style=\"color: #097482;\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft wp-image-62280\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/forme6-300x287.jpg\" alt=\"\" width=\"150\" height=\"144\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/forme6-300x287.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/forme6-13x12.jpg 13w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/forme6-36x36.jpg 36w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2023\/12\/forme6.jpg 400w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/>This paved the way for a new vision of the concept of \u00ab\u00a0architecture\u00a0\u00bb associated with metamaterials, i.e. <\/span><strong><span style=\"color: #097484;\">\u00ab\u00a0introducing, between the microstructure scale of the constituent material and that of the macrostructure, one or more other scales of organization of matter\u00a0\u00bb<\/span><\/strong><span style=\"color: #097482;\">. The hierarchical or fractal structures found in most biological systems, where the same geometry can be repeated in a \u00ab\u00a0self-similar\u00a0\u00bb or \u00ab\u00a0non-self-similar\u00a0\u00bb way on several scales, are clear examples. These so-called mesoscopic scales can be weakly separated (coupled) from the macroscopic scale, and<\/span> <strong><span style=\"color: #097484;\">induce a wealth of effective behaviors.<\/span><\/strong><\/p>\n<\/div><\/section><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-wns4tc-24fa20f08b4573c9325329bc6b56de51\">\n.flex_column.av-wns4tc-24fa20f08b4573c9325329bc6b56de51{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-wns4tc-24fa20f08b4573c9325329bc6b56de51 av_one_half  avia-builder-el-11  el_after_av_one_full  el_before_av_one_half  first flex_column_div av-zero-column-padding  column-top-margin'     ><section  class='av_textblock_section av-lq2hhk08-2b698380024dc00bff08dc43dac32f95'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h5>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-qawvnx-eb0fa84a59d44b41dd8d2a500ef04acb\">\n.av_font_icon.av-qawvnx-eb0fa84a59d44b41dd8d2a500ef04acb{\ncolor:#097482;\nborder-color:#097482;\n}\n.av_font_icon.av-qawvnx-eb0fa84a59d44b41dd8d2a500ef04acb .av-icon-char{\nfont-size:20px;\nline-height:20px;\n}\n<\/style>\n<span  class='av_font_icon av-qawvnx-eb0fa84a59d44b41dd8d2a500ef04acb avia_animate_when_visible av-icon-style- avia-icon-pos-left avia-icon-animate'><span class='av-icon-char' aria-hidden='true' data-av_icon='\ue881' data-av_iconfont='entypo-fontello' ><\/span><\/span><\/h5>\n<h5><span style=\"color: #097482;\">Bio-inspiration in metamaterials: Nature, the grand master of material architecture<\/span><\/h5>\n<p>While mankind has only recently begun to exploit complex architectures (mainly due to technological limitations), <strong>Nature<\/strong>, thanks to millions of years of evolution, <strong>is a great master of \u00ab\u00a0material architecture\u00a0\u00bb to obtain specific advanced properties and geometries focused on precise functionalities.<\/strong> Indeed, the common feature leading to these surprising properties often lies in the hierarchical organization of matter on several scales (an organization often observed in many natural materials such as wood, bone, sponges, etc.). Consequently, increasing attention has been devoted in recent years to the synthesis of artificial materials inspired by Nature, but primarily targeting quasi-static performance. In contrast, the consideration of hierarchical organization in the elementary cell design of phononic crystals and (mechanical and acoustic) metamaterials[1] is only very recent.<\/p>\n<p>In this context, we presented a <strong>new type of metamaterial<\/strong> consisting of a polymer matrix with <strong>\u00ab\u00a0non-self-similar\u00a0\u00bb cross-shaped holes repeated at several scale levels<\/strong>. This enabled us to achieve highly attenuative behavior with respect to elastic waves on several frequency scales, thanks to the fact that the \u00ab\u00a0non-self-similar hierarchy\u00a0\u00bb leads to the opening of multiple (and wide) frequency bandgaps, even in the sub-wavelength regime (i.e., when the wavelength of the wave to be attenuated is much greater than the size of the structure itself).<\/p>\n<p><em>(2) Material architecture is understood here as \u00ab\u00a0the organization of a unit cell repeated on several levels of scale\u00a0\u00bb.<\/em><\/p>\n<\/div><\/section><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-wns4tc-1db3423f7cd08c59a5a437f03f40996e\">\n.flex_column.av-wns4tc-1db3423f7cd08c59a5a437f03f40996e{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-wns4tc-1db3423f7cd08c59a5a437f03f40996e av_one_half  avia-builder-el-14  el_after_av_one_half  el_before_av_one_full  flex_column_div av-zero-column-padding  column-top-margin'     ><section  class='av_textblock_section av-lq2hhk08-2b698380024dc00bff08dc43dac32f95'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p>Through <strong>numerical models and scanning laser Doppler vibrometer measurements,<\/strong> we have revealed that the \u00ab\u00a0non-self-similar\u00a0\u00bb hierarchy allows the opening of such forbidden bands thanks to the simultaneous activation of multiple attenuation mechanisms: Bragg scattering, local resonance and\/or inertial amplification. These mechanisms have been clearly identified by analyzing the imaginary part of the wavenumber. The multi-mechanism design approach leads to enriched dynamics at different scales (opening of additional bandgaps, conservation of the existing frequency-shifted bandgaps, as well as the possibility of preserving the global deformation mechanisms of previous hierarchical levels, despite variations in the mass\/rigidity ratio of the overall system).<\/p>\n<\/div><\/section><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-wns4tc-219c562a3ab67f2abbe45e15506bd8de\">\n@keyframes av_boxShadowEffect_av-wns4tc-219c562a3ab67f2abbe45e15506bd8de-column {\n0%   { box-shadow:  0 0 0 0 #a8a8a8; opacity: 1; }\n100% { box-shadow:  0 0 10px 0 #a8a8a8; opacity: 1; }\n}\n.flex_column.av-wns4tc-219c562a3ab67f2abbe45e15506bd8de{\nbox-shadow: 0 0 10px 0 #a8a8a8;\nborder-radius:20px 20px 20px 20px;\npadding:20px 20px 20px 20px;\nbackground-color:rgba(85,160,159,0.9);\n}\n<\/style>\n<div  class='flex_column av-wns4tc-219c562a3ab67f2abbe45e15506bd8de av_one_full  avia-builder-el-16  el_after_av_one_half  el_before_av_hr  first flex_column_div shadow-not-animated  column-top-margin'     ><section  class='av_textblock_section av-lq2hhk08-2b698380024dc00bff08dc43dac32f95'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p><strong><span style=\"color: #ffffff;\"> In conclusion, the enrichment of the architecture of metamaterials at the mesoscale induces effective behaviors of great richness, offering new perspectives for the control of elastic waves, favoring the simultaneous activation of various wave attenuation mechanisms.<\/span><\/strong><br \/>\n<span style=\"color: #ffffff;\">\u00a0<\/span><br \/>\n<span style=\"color: #ffffff;\"><em>References<\/em><\/span><br \/>\n<span style=\"color: #ffffff;\"><em>[1] Mazzotti, [\u2026], Miniaci. Bio-inspired non-self-similar hierarchical elastic metamaterials. International Journal of Mechanical Sciences 241:107915 (2023).<\/em><\/span><br \/>\n<span style=\"color: #ffffff;\"><em>[2] Miniaci et al. Bio-inspired hierarchical dissipative metamaterials, Physical Review Applied, 10, 024012 (2018).<\/em><\/span><\/p>\n<\/div><\/section><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-lq3rrbn6-b2fad551015528b25fb537190ccf1056\">\n#top .hr.hr-invisible.av-lq3rrbn6-b2fad551015528b25fb537190ccf1056{\nheight:20px;\n}\n<\/style>\n<div  class='hr av-lq3rrbn6-b2fad551015528b25fb537190ccf1056 hr-invisible  avia-builder-el-18  el_after_av_one_full  el_before_av_textblock'><span class='hr-inner'><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<section  class='av_textblock_section av-lq3ru9ya-f6b76a2798525607f872d4bf4739c6be'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><div  class='avia-button-wrap av-rpqvoq-9a05bde6f0cd05381e571d282e3fe825-wrap avia-button-left  avia-builder-el-20  avia-builder-el-no-sibling'><a href='mailto:marco.miniaci@univ-lille.fr'  class='avia-button av-rpqvoq-9a05bde6f0cd05381e571d282e3fe825 av-link-btn avia-icon_select-yes-left-icon avia-size-small avia-position-left avia-color-silver'   aria-label=\"marco.miniaci@univ-lille.fr\"><span class='avia_button_icon avia_button_icon_left' aria-hidden='true' data-av_icon='\ue805' data-av_iconfont='entypo-fontello'><\/span><span class='avia_iconbox_title' >marco.miniaci@univ-lille.fr<\/span><\/a><\/div>\n<\/div><\/section>","protected":false},"excerpt":{"rendered":"","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[297],"tags":[],"class_list":["post-61669","post","type-post","status-publish","format-standard","hentry","category-newsletter"],"_links":{"self":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/61669","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/comments?post=61669"}],"version-history":[{"count":0,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/61669\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media?parent=61669"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/categories?post=61669"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/tags?post=61669"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}