{"id":20610,"date":"2026-05-05T14:58:50","date_gmt":"2026-05-05T12:58:50","guid":{"rendered":"https:\/\/navier-lab.fr\/?p=20610"},"modified":"2026-05-05T14:59:53","modified_gmt":"2026-05-05T12:59:53","slug":"phd-defense-malek-chihaoui","status":"publish","type":"post","link":"https:\/\/navier-lab.fr\/en\/phd-defense-malek-chihaoui\/","title":{"rendered":"PhD Defense \u2013 Malek Chihaoui"},"content":{"rendered":"<section class=\"kc-elm kc-css-325514 kc_row\"><div class=\"kc-row-container  kc-container\"><div class=\"kc-wrap-columns\"><div class=\"kc-elm kc-css-430142 kc_col-sm-12 kc_column kc_col-sm-12\"><div class=\"kc-col-container\"><div class=\"kc-elm kc-css-183438 kc_text_block\"><\/p>\n<p>Malek Chiahoui, a PhD candidate in the Architectured Materials and Structures team will defend his dissertation titled \u00ab<em> Identification of the railway track irregularities from onboard acceleration measurements<\/em> \u00bb, on Thursday, May 07\u00a0 at 02:00 pm in the Navier amphitheater.<\/p>\n<section class=\"kc-elm kc-css-927749 kc_row\">\n<div class=\"kc-row-container kc-container\">\n<div class=\"kc-wrap-columns\">\n<div class=\"kc-elm kc-css-1550185 kc_column kc_col-sm-12\">\n<div class=\"kc-col-container\">\n<div class=\"kc-elm kc-css-729267 kc_text_block\">\n<p>Composition of the jury :<\/p>\n<ul>\n<li>Paul Fisette, Universit\u00e9 de Louvain, Reviewer<\/li>\n<li>R\u00e9gis Cottereau, LMA, Reviewer<\/li>\n<li>Etienne Balmes, ENSAM, Examinator<\/li>\n<li>Guillaume Puel, Centrale Supelec, Examinator<\/li>\n<li>Christine Funfschiling, SNCF, Co-thesis Supervisor<\/li>\n<li>Guillaume Perrin, , Universit\u00e9 Gustave Eiffel, Co-thesis Supervisor<\/li>\n<li><span style=\"font-style: inherit;\">Denis Duhamel, Professeur, Ecole Nationale des Ponts et Chauss\u00e9es, Thesis Director<\/span><\/li>\n<\/ul>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n<section class=\"kc-elm kc-css-915219 kc_row\">\n<div class=\"kc-row-container kc-container\">\n<div class=\"kc-wrap-columns\">\n<div class=\"kc-elm kc-css-237917 kc_col-sm-12 kc_column kc_col-sm-12\">\n<div class=\"kc-col-container\">\n<div class=\"kc-elm kc-css-717167 kc_accordion_wrapper\">\n<div class=\"kc-elm kc-css-738242 kc_accordion_section group \">\n<div class=\"kc_accordion_content ui-accordion-content kc_clearfix\">\n<div class=\"kc-panel-body\">\u00a0<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n<p>\n<\/div><div class=\"kc-elm kc-css-936628 kc_accordion_wrapper\">\n<div class=\"kc-elm kc-css-45484 kc_accordion_section group \"><h3 class=\"kc_accordion_header ui-accordion-header\"><span class=\"ui-accordion-header-icon ui-icon\"><\/span><a href=\"#abstract\" data-prevent=\"scroll\"><i class=\"\"><\/i> Abstract<\/a><\/h3><div class=\"kc_accordion_content ui-accordion-content kc_clearfix\"><div class=\"kc-panel-body\"><div class=\"kc-elm kc-css-437583 kc_text_block\"><\/p>\n<p>The monitoring of track irregularities is essential to ensure safety, passenger comfort, and operational efficiency. These geometric irregularities arise from repeated train loads and environmental effects such as temperature-induced buckling and substructure settlement. Currently, track geometry is measured using dedicated inspection trains equipped with complex systems and specialized personnel. As a complementary approach, accelerometers installed on commercial trains offer a promising solution, enabling more frequent and cost-effective monitoring and supporting maintenance planning.<\/p>\n<p>This thesis investigates railway track geometry monitoring using onboard accelerometers mounted on commercial trains. The first research axis focuses on quantifying uncertainties in the identification of vertical offset and cross-level irregularities through double integration of vertical axle-box accelerations. As the assumptions underlying this method are not fully understood, a geometric analysis and numerical simulations using railway dynamics software are conducted. A rigorous mathematical derivation of parasitic quasi-static terms interfering with the identification is presented, demonstrating their importance for the accurate assessment of long-wavelength irregularities.<\/p>\n<p>The second research axis addresses lateral irregularities, whose reconstruction from onboard accelerometers is significantly more complex. In particular, the lateral alignment irregularity identification is studied. To improve understanding of this problem, simplified surrogate models incorporating key nonlinearities are developed and inverted to characterize the relationships between measurements and track geometry. Iterative estimation methods are then applied and extended to more complex railway dynamics models. Finally, a parametric study and a simulation-based refinement technique, treating the software as a black box, are shown to provide satisfactory results even under degraded identification conditions.<\/p>\n<p>\n<\/div><\/div><\/div><\/div><\/div>\n<\/div><\/div><\/div><\/div><\/section>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":10,"featured_media":20603,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[266,251,293,299],"tags":[],"class_list":["post-20610","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-actualites-en","category-annonces-en","category-annonces-msa-en","category-soutenances-de-these-en"],"acf":[],"_links":{"self":[{"href":"https:\/\/navier-lab.fr\/en\/wp-json\/wp\/v2\/posts\/20610","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/navier-lab.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/navier-lab.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/navier-lab.fr\/en\/wp-json\/wp\/v2\/users\/10"}],"replies":[{"embeddable":true,"href":"https:\/\/navier-lab.fr\/en\/wp-json\/wp\/v2\/comments?post=20610"}],"version-history":[{"count":6,"href":"https:\/\/navier-lab.fr\/en\/wp-json\/wp\/v2\/posts\/20610\/revisions"}],"predecessor-version":[{"id":20620,"href":"https:\/\/navier-lab.fr\/en\/wp-json\/wp\/v2\/posts\/20610\/revisions\/20620"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/navier-lab.fr\/en\/wp-json\/wp\/v2\/media\/20603"}],"wp:attachment":[{"href":"https:\/\/navier-lab.fr\/en\/wp-json\/wp\/v2\/media?parent=20610"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/navier-lab.fr\/en\/wp-json\/wp\/v2\/categories?post=20610"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/navier-lab.fr\/en\/wp-json\/wp\/v2\/tags?post=20610"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}