{"id":55578,"date":"2022-12-01T16:59:48","date_gmt":"2022-12-01T14:59:48","guid":{"rendered":"https:\/\/www.iemn.fr\/?p=55578"},"modified":"2022-12-01T16:59:48","modified_gmt":"2022-12-01T14:59:48","slug":"these-m-therzi-surveillance-passive-de-structures-basee-sur-le-bruit-ambiant-via-lexploitation-de-la-non-linearite-acoustique-de-contact","status":"publish","type":"post","link":"https:\/\/www.iemn.fr\/en\/theses-2022\/these-m-therzi-surveillance-passive-de-structures-basee-sur-le-bruit-ambiant-via-lexploitation-de-la-non-linearite-acoustique-de-contact.html","title":{"rendered":"THESE : M. THERZI &#8211; Surveillance passive de structures bas\u00e9e sur le bruit ambiant via l&rsquo;exploitation de la non-lin\u00e9arit\u00e9 acoustique de contact"},"content":{"rendered":"<div id='layer_slider_1'  class='avia-layerslider main_color avia-shadow  avia-builder-el-0  el_before_av_heading  avia-builder-el-first  container_wrap sidebar_right'  style='height: 261px;'  ><div id=\"layerslider_58_9ekaxzr00ozx\" data-ls-slug=\"homepageslider\" class=\"ls-wp-container fitvidsignore ls-selectable\" style=\"width:1140px;height:260px;margin:0 auto;margin-bottom: 0px;\"><div class=\"ls-slide\" data-ls=\"duration:6000;transition2d:5;\"><img loading=\"lazy\" decoding=\"async\" width=\"2600\" height=\"270\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1.jpg\" class=\"ls-bg\" alt=\"\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1.jpg 2600w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-300x31.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-768x80.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-1030x107.jpg 1030w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-1500x156.jpg 1500w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-705x73.jpg 705w\" sizes=\"auto, (max-width: 2600px) 100vw, 2600px\" \/><ls-layer style=\"font-size:14px;text-align:left;font-style:normal;text-decoration:none;text-transform:none;font-weight:700;letter-spacing:0px;border-style:solid;border-color:#000;background-position:0% 0%;background-repeat:no-repeat;width:180px;height:30px;left:0px;top:231px;line-height:32px;color:#ffffff;border-radius:6px 6px 6px 6px;padding-left:50px;background-color:rgba(0, 0, 0, 0.57);\" class=\"ls-l ls-ib-icon ls-text-layer\" data-ls=\"minfontsize:0;minmobilefontsize:0;\"><i class=\"fa fa-quote-right\" style=\"color:#ffffff;margin-right:0.8em;font-size:1em;transform:translateY( -0.125em );\"><\/i>ACTUALITES<\/ls-layer><\/div><\/div><\/div><div id='after_layer_slider_1'  class='main_color av_default_container_wrap container_wrap sidebar_right'  ><div class='container av-section-cont-open' ><div class='template-page content  av-content-small alpha units'><div class='post-entry post-entry-type-page post-entry-55578'><div class='entry-content-wrapper clearfix'>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-lb57ci8x-1a78946c118af2d2c27f3d6a14396af3\">\n#top .av-special-heading.av-lb57ci8x-1a78946c118af2d2c27f3d6a14396af3{\nmargin:0 0 10px 0;\npadding-bottom:4px;\n}\nbody .av-special-heading.av-lb57ci8x-1a78946c118af2d2c27f3d6a14396af3 .av-special-heading-tag .heading-char{\nfont-size:25px;\n}\n.av-special-heading.av-lb57ci8x-1a78946c118af2d2c27f3d6a14396af3 .av-subheading{\nfont-size:15px;\n}\n<\/style>\n<div  class='av-special-heading av-lb57ci8x-1a78946c118af2d2c27f3d6a14396af3 av-special-heading-h2  avia-builder-el-1  el_after_av_layerslider  el_before_av_hr  avia-builder-el-first'><h2 class='av-special-heading-tag'  itemprop=\"headline\"  >THESE : M. THERZI \u2013 Surveillance passive de structures bas\u00e9e sur le bruit ambiant via l\u2019exploitation de la non-lin\u00e9arit\u00e9 acoustique de contact <\/h2><div class=\"special-heading-border\"><div class=\"special-heading-inner-border\"><\/div><\/div><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-18u73nj-dad6a947580930e400fc42ba200e80f1\">\n#top .hr.av-18u73nj-dad6a947580930e400fc42ba200e80f1{\nmargin-top:5px;\nmargin-bottom:5px;\n}\n.hr.av-18u73nj-dad6a947580930e400fc42ba200e80f1 .hr-inner{\nwidth:100%;\n}\n<\/style>\n<div  class='hr av-18u73nj-dad6a947580930e400fc42ba200e80f1 hr-custom  avia-builder-el-2  el_after_av_heading  el_before_av_textblock  hr-left hr-icon-no'><span class='hr-inner inner-border-av-border-thin'><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<section  class='av_textblock_section av-jriy64i8-2f4600354c0449b610997916bbd9b6bc'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" >\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-13ewzjw-68e036126b913e5028f77311dc66b825\">\n.av_font_icon.av-13ewzjw-68e036126b913e5028f77311dc66b825{\ncolor:#bfbfbf;\nborder-color:#bfbfbf;\n}\n.av_font_icon.av-13ewzjw-68e036126b913e5028f77311dc66b825 .av-icon-char{\nfont-size:60px;\nline-height:60px;\n}\n<\/style>\n<span  class='av_font_icon av-13ewzjw-68e036126b913e5028f77311dc66b825 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='\ue8c9' data-av_iconfont='entypo-fontello' ><\/span><\/span>\n<p><strong>M. THERZI<br \/>\n<\/strong><\/p>\n<p>Soutenance : <strong>14 mars 2022<br \/>\n<\/strong>Th\u00e8se de doctorat en Acoustique, Universit\u00e9 Polytechnique Hauts de France,<\/p>\n<\/div><\/section>\n<section  class='av_textblock_section av-jtefqx33-628129dba2299b2ecd65ebfc92eac29d'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><div  class='hr av-kjh3zw-4dff888f744b728a1aca9b3a0971493a hr-default  avia-builder-el-6  avia-builder-el-no-sibling'><span class='hr-inner'><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<h5><strong><span style=\"color: #800000;\">\u00a0<\/span><\/strong><\/h5>\n<h5>Summary:<\/h5>\n<p>Le contr\u00f4le-qualit\u00e9 de mat\u00e9riaux par m\u00e9thodes acoustiques sans r\u00e9f\u00e9rence suscite aujourd\u2019hui un grand int\u00e9r\u00eat en contr\u00f4le sant\u00e9 int\u00e9gr\u00e9 (CSI) au vu de la variabilit\u00e9 des conditions environnementales et op\u00e9rationnelles. Dans ce manuscrit, nous proposons une m\u00e9thode de d\u00e9tection synchrone\/non synchrone de d\u00e9faut soumis \u00e0 des sollicitations basses fr\u00e9quences, permettant une localisation sans \u00e9tat hypoth\u00e9tique \u2018sans d\u00e9faut\u2019. Une s\u00e9rie de tests \u2018pompe-sonde\u2019 a \u00e9t\u00e9 men\u00e9e sur une plaque d\u2019aluminium. Un pot vibrant est fix\u00e9 sur cette derni\u00e8re afin de la mettre en vibration \u00e0 une fr\u00e9quence de quelques Hz. Une bille solidaire d\u2019une lame en acier est press\u00e9e contre la plaque (contact Hertzien) et joue le r\u00f4le d\u2019un d\u00e9faut (reproduisant ainsi un contact tel qu\u2019on peut le rencontrer par exemple entre deux fronts d\u2019une fissure). Un r\u00e9seau de transducteurs pi\u00e9zo\u00e9lectriques est utilis\u00e9 pour faire l\u2019imagerie ultrasonore. Le principe de la d\u00e9tection repose sur la modulation du contact entre la plaque et la bille par la vibration pompe basse fr\u00e9quence. Des mesures ultrasonores r\u00e9p\u00e9t\u00e9es (onde sonde) permettent ainsi d\u2019interroger le d\u00e9faut dans plusieurs \u00e9tats de sollicitation. Un algorithme d\u2019imagerie diff\u00e9rentielle permet alors de mettre en \u00e9vidence et localiser le d\u00e9faut. Deux modes de d\u00e9tection ont \u00e9t\u00e9 test\u00e9s : 1) mode synchrone entre la pompe et les signaux ultrasonores et 2) mode non synchrone. Dans ce dernier cas, une correction par des coefficients de pond\u00e9ration ad-hoc permet d\u2019am\u00e9liorer la d\u00e9tection. Une \u00e9tude param\u00e9trique a \u00e9t\u00e9 \u00e9galement r\u00e9alis\u00e9e en reliant le contraste des images en fonction de la section de diffusion de d\u00e9faut. Ceci a permis de d\u00e9finir un seuil minimal de d\u00e9tection d\u2019un d\u00e9faut de type contact variable. L\u2019application de cette m\u00e9thode \u00e0 l\u2019imagerie passive par corr\u00e9lation de bruit a donn\u00e9 des r\u00e9sultats encourageants, \u00e0 condition d\u2019augmenter la densit\u00e9 du r\u00e9seau de capteurs ultrasonores. Enfin, des simulations num\u00e9riques en 2D, mod\u00e9lisant l\u2019interaction d\u2019une onde ultrasonore avec un contact de frottement type \u2018Hertz-Mindlin\u2019 ont \u00e9t\u00e9 r\u00e9alis\u00e9es afin de comparer le d\u00e9faut actuel (bille press\u00e9e sur la plaque) avec un d\u00e9faut r\u00e9aliste (une fissure).<\/p>\n<h5>Abstract:<\/h5>\n<p>Material quality control by acoustic methods without reference is nowadays of great interest in integrated health control (IHC) due to the variability of environmental and operational conditions. In this manuscript, we propose a method for synchronous\/non-synchronous detection of defects subjected to low-frequency solicitations, allowing a localization without hypothetical \u2018defect-free\u2019 state. A series of \u2018pump-probe\u2019 tests has been conducted on an aluminum plate. A vibrating pot is fixed on the latter in order to put it in vibration at a frequency of a few Hz. A ball attached to a steel blade is pressed against the plate (Hertzian contact) and plays the role of a defect (thus reproducing a contact such as one can meet it for example between two faces of a crack). An array of piezoelectric transducers is used to perform the ultrasonic imaging. The principle of the detection is based on the modulation of the contact between the plate and the ball by the low frequency pump vibration. Repeated ultrasonic measurements (probe wave) allow to interrogate the defect in several states of stress. A differential imaging algorithm is then used to highlight and locate the defect. Two detection modes have been tested: 1) synchronous mode between the pump and the ultrasonic signals and 2) non-synchronous mode. In this last case, a correction by ad-hoc weighting coefficients allows to improve the detection. A parametric study was also performed by relating the contrast of the images as a function of the defect diffusion section. This allowed to define a minimum threshold of detection of a variable contact type defect. The application of this method to passive imaging by noise correlation gave encouraging results, provided that the density of the ultrasonic sensor network is increased. Finally, 2D numerical simulations modeling the interaction of an ultrasonic wave with a \u2018Hertz-Mindlin\u2019 type friction contact were performed in order to compare the actual defect (ball pressed on the plate) with a realistic defect (a crack).<\/p>\n<\/div><\/section>","protected":false},"excerpt":{"rendered":"","protected":false},"author":20,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[316],"tags":[],"class_list":["post-55578","post","type-post","status-publish","format-standard","hentry","category-theses-2022"],"_links":{"self":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/55578","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\/20"}],"replies":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/comments?post=55578"}],"version-history":[{"count":0,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/55578\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media?parent=55578"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/categories?post=55578"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/tags?post=55578"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}