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Yannick Tillier

Yannick Tillier

Professor

Center · CEMEF

Discipline(s)
Imaging, Medical Technologies, Solid Mechanics
Topic(s)
Additive Manufacturing, Biomaterials, Biomechanics, Digital Twin, Personalized and Predictive Medicine, Prosthetics

Keywords

Team

CSM - Mécanique Numériques des Solides

Biography

Yannick Tillier is a teacher-researcher, specializing in biomechanics and materials science applied to health. His work lies at the interface of materials engineering, continuum mechanics, and numerical modeling.

His research focuses on the experimental characterization and multi-scale modeling of biological tissues (soft and mineralized) and innovative biomaterials. He notably relies on biomimicry to optimize the mechanical behavior of medical devices and tissue substitutes. For example, he coordinates the ANR CMADENT project, centered on additive manufacturing and finite element simulation of dental restorations with property gradients. He is also interested in the development of new hydrogels and aerogels adapted to medical applications, particularly in the osteoarticular field.

The advanced finite element simulation methods he develops make it possible to analyze the mechanical interactions between implants and anatomical structures. The applications directly concern odontology, maxillofacial surgery, and orthopedics. His recent projects also integrate artificial intelligence to refine clinical simulations and design personalized therapeutic solutions.

Highly committed to teaching, he actively participates in the training of engineering students. He is responsible for several health-related courses, including the “Health & Living” option in the 3rd year. He also contributes to the animation of the Francophone and international biomechanics community, notably through his responsibilities within the Board of Directors of the Society of Biomechanics.

Publication(s)

Projects

  • 2022-2027 ANR CMADENT "Conception de MAtériaux DENTaires à gradients de propriétés par fabrication additive" Lead Investigator La dent présente un gradient naturel d’élasticité lié à la présence de dentine (tissu minéral poreux) et d’émail (hautement minéralisé, 2 à 4 fois plus rigide), reliés par une zone de transition de quelques microns. La restauration des pertes de substance dentaire volumineuses par Conception et Fabrication Assistées par Ordinateur (CFAO) ne reproduit pas ce gradient d’élasticité et limite la durabilité des restaurations. L’objectif du projet CMADENT (ANR-22-CE51-0017) est de proposer une alternative à la CFAO (i) en remplaçant l’usinage par une technique de fabrication additive qui permet de limiter la perte de matière tout en garantissant des propriétés supérieures à celles des restaurations directes, (ii) en mimant les gradients de propriétés naturels de la dent et (iii) en développant de nouveaux matériaux moins toxiques et bioactifs pour prévenir l’apparition de caries secondaires. Le procédé DLP (Digital Light Processing) retenu est relativement rapide (une douzaine de pièces imprimées vs 3 en CFAO classique) et peu coûteux (15 k€ vs 100 k€ pour une machine de production en CFAO), deux avantages importants pour permettre une adoption rapide par les praticiens.
  • 2016-2021 ANR TOOTHBOX "Boîte à outils expérimentale et numérique pour le développement de composites dentaires plus durables" Co-Investigator La carie dentaire est la pathologie la plus répandue au monde. Le nombre annuel de restaurations dentaires à l’aide de matériaux composites est considérable mais leur durée de vie est malheureusement limitée. Un chirurgien-dentiste consacre autant de temps à intervenir sur des restaurations défectueuses qu’à prendre en charge de nouvelles lésions carieuses. Une des limitations majeures des composites dentaires est leur propension à se contracter lors de leur polymérisation, ce qui complique la pratique clinique et tend à fragiliser le matériau tout en favorisant le risque d’apparition de lésions carieuses secondaires. Développer de nouveaux matériaux faciles à manipuler et présentant une meilleure longévité constitue deux axes d’amélioration. Cela passe par une meilleure compréhension des liens entre les propriétés mécaniques du composite à l’échelle macroscopique (celle de la dent), l’organisation et les propriétés de ses composants à l’échelle microscopique, et leur évolution au cours du temps. Les partenaires du projet TOOTHBOX (chirurgiens-dentistes, mécaniciens, numériciens et physico-chimistes) ont décidé de s’unir afin de développer les outils expérimentaux et numériques nécessaires à une meilleure compréhension du problème.
  • 2024-2029 Projet RHU Rebone Scientific Director Le projet REBONE vise à optimiser la prise en charge des traumatismes osseux complexes en combinant réalité mixte, modélisation 3D et intelligence artificielle. À partir des données d'imagerie médicale, le projet développe un véritable « jumeau numérique » du patient pour simuler et planifier l'acte chirurgical en amont. Cette approche permet aux équipes médicales d'évaluer plusieurs stratégies opératoires, de fiabiliser les gestes chirurgicaux et de définir un protocole personnalisé.

Teaching

Mechanics of Materials and Structures (PI MECAERO)

Lecturer

Project (PI MECAERO)

Lecturer

Implantable Devices and Materials for Medical Use

Course Director

Syllabus The numerous and extremely varied concepts covered in this course will be illustrated by the teaching team using one or two real-life cases involving organs or tissues (dental, osteoarticular, cardiovascular, etc.) to serve as “guiding themes” throughout the course. During the first session, students will take on the role of an R&D team tasked with developing a material for a healthcare application. They will thus choose their own “guiding theme,” to which they will apply the various concepts covered from one class to the next. Each class session will be organized into three phases: - I - a presentation followed by a discussion during which a pair or trio of students will present how the material from the previous class applies to their project; - II - an introductory lecture on fundamental concepts or a presentation by a guest speaker (a physician, industry representative, or regulatory specialist); - III - a group work session to apply the concepts covered to the selected case study. Furthermore, once the case study has been selected, the teaching team will work with the students to contact one or more specialists in the field (physician, researcher, engineer, etc.), to whom a summary of the study will be presented at the end of the course in the form of a report and a project defense presentation. Students will thus be able to test their approach against the critical opinions of experts and professionals. Content The program will consist of six sessions during which the following concepts will be covered: • the composition and organization of biological materials, • biocompatibility, bioactivity, biointegration, and bioresorbability, • the mechanical properties of tissues and their mechanical characterization in vivo and in vitro, • the major classes of biomaterials (polymers, metals, ceramics), • new manufacturing processes and the tissue engineering approach, • methods for evaluating the in-service performance of biomaterials and medical devices, • regulatory aspects, • consideration of medical constraints, • the industrial context.

Experimental Mechanics

Guest Lecturer

The course has two main objectives. Drawing on examples from industry, the course first aims to help students understand the challenges involved in a mechanical testing campaign and to equip them with the tools needed to design experimental plans for the mechanical characterization of materials. With this in mind, the course will begin with a description of standardized tests to highlight their limitations, followed by a presentation of original or “non-standard” tests that are as well-instrumented as possible. To this end, part of the course will be devoted to the study of non-contact thermomechanical measurement techniques (infrared thermography and digital image correlation). In a second phase, the focus will be on establishing the link between continuum mechanics, thermomechanical behavior equations, and experimental characterization. The concepts of stress and strain analysis will be reviewed to understand the methods for optimizing behavior and damage mechanisms, which we aim to identify through the tests. The in-person component (29 hours) is structured into plenary sessions (12 hours), mini-projects (in pairs or groups of three) (15 hours), and project presentations before a panel (30 minutes). Students’ independent work (6 hours) includes: Understanding the mini-project, literature review, scientific analysis and interpretation of the results obtained, writing a summary, and preparing an oral presentation

Materials Science and Engineering (MSE) track

Guest Lecturer

The Second Year: Discover, Observe, Experiment The two-week elective period is devoted to a mini-project in pairs, in one of the School’s two laboratories (the Materials Center in Evry or the Materials Processing Center in Sophia-Antipolis, with more than 70 faculty members supporting the elective). The topics revolve around a specific industrial project. The focus is on discovering physical, chemical, and mechanical phenomena—and on quantifying them. A detailed report and an oral presentation allow students not only to develop communication skills but, above all, to learn from one another. Some topics include: investigation of a railway brake failure, investigation of non-conformity in metal seals, welding (instrumented testing and numerical modeling), study of foam formation mechanisms for automotive seats, aerogel formation for super-insulation or biomedical applications... The 3rd Year: Understanding, Making Choices, Optimizing The two highlights of the third year are the elective month (starting at the beginning of the academic year) and the personal project, which takes up the rest of the time allocated to the elective. The elective month: “Materials and Engineers” in a specific industrial sector. The elective month is devoted to materials engineering and focuses on a specific industrial sector (2004 and 2005: the automotive industry; 2006 and 2007: aerospace; 2008 and 2009: construction; 2010 and 2011: energy; 2012 and 2013: healthcare; 2014 and 2015: aerospace). The wide range of activities fosters hands-on learning and helps build a cohesive group, enriched by the diverse backgrounds and personalities of both students and teachers: industrial tours: the development, processing, and use of materials in the chosen field; a few lectures given by industry experts; “Industrial Discovery” mini-projects: 5 days in groups of 2 to 4 students at an industrial site, supervised by on-site engineers, working on an engineering problem; a written report (for internal company use) and an oral presentation allow the different groups to share the knowledge and experiences gained in the field; a few “classes”—which are actually preparatory sessions for the visits and “debriefing” sessions in the form of Q&A sessions with faculty regarding the lectures and industrial visits. The elective project: applying methods and knowledge to solve an industrial problem. These individual elective projects form the backbone of the third year. Defined as early as October, in accordance with each student’s preferences, they focus on a clearly identified industrial problem. Lasting at least 4 months (a total of 8 months for Polytech students in the “specialized track”), they take place at an industrial site under dual supervision: engineers from the company on one hand, and a faculty researcher from one of the School’s two “Materials” laboratories on the other. The emphasis is on understanding the underlying phenomena and solving the practical problem at hand. Some representative elective topics covered in recent years: selection of a material for a Formula 1 car part (Renault, Viry-Châtillon); modeling of thin films deposited on glass (Saint-Gobain, Thourotte); selection and sizing of a shock-absorbing foam (SNCF, Le Mans); feasibility of coating pistons via plasma spraying (Toyota, Evry—Belgium – Japan); an innovative steel continuous casting process (Vallourec, Aulnoye-Aymeries / Brazil); optimization of the fiber-reinforced polymer injection molding process (Bosch, Germany); analysis of medieval gilded enameled glass (Laboratoire des Musées de France, Paris); prediction of fracture properties of steels for gas pipelines (ArcelorMittal, Ghent, Belgium). acceptance criteria for forging defects (PSA, La Garenne-Colombes); painting defects on automotive plastic body parts (Mécaplast, Monaco) welding of superalloy parts for space launch vehicles (Snecma, Vernon) improvement of non-destructive testing of power plant components (EDF, Saint-Denis) decontamination of concrete used in civil engineering for nuclear power plants (Bouygues, St-Quentin / CEA, Marcoule) Improving the manufacturing of composite parts for the aerospace industry (Dassault, Argenteuil) Material selection for endoscopic probes with integrated microscopes (Mauna Kea Technologies, Paris) Key features of the track: Hands-on experience! The track includes very few courses in the traditional sense: knowledge and skills are acquired through courses offered to all students (core curriculum, specialized courses) and, above all, by sharing each student’s real-world experiences in the field. It’s about experimenting on your own and as part of a team (with dual mentoring by an industrial engineer and a faculty researcher). Intensive group work The diversity and number of students in the track allow everyone to learn from and with one another. This provides effective training in self-directed learning methods that engineers will use throughout their careers to remain key players in their fields of expertise and take control of their professional development. Interdisciplinary Approach The field of materials lies at the intersection of disciplines such as physics, chemistry, mechanics, applied mathematics, and numerical modeling. Elective projects often include both an experimental component and a modeling component, providing a well-rounded education in materials science. The track covers ceramics, “plastics,” metals, and alloys, as well as ancient artifacts (archaeology) and the latest innovations (“biological” steels, bio-based and non-bio-based aerogels, etc.).

Engineering and Health Research (Research Quarter)

Course Director

Santé et Vivant option

Course Director

PhD supervision

  • 2025 Développement d’un modèle biomécanique patient-spécifique basé sur le scanner biénergie pour guider le traitement des fractures complexes Paul-Alexis RANC
  • 2024 Consideration of biomechanics in the customization of an implantable osteosynthesis medical device: application to the reduction of complex fractures. GANACHON Marine
  • 2024 Mouvements cuspidiens sous contrainte occlusale: répercussions mécaniques sur les restaurations adhésives Marie BERNABEU
  • 2023 Design of dental materials with property gradients by additive manufacturing GUÉRANDELLE Léa
  • 2022 Biosourced nanocomposite hydrogels and aerogels for biomedical applications BOURAS Hiba
  • 2022 Relation structure-mécanique dans les fibres d'hydrogel d'alcool polyvinylique anisotrope pour des substituts de tissus mous biomimétiques DIAZ COLINA Andrea
  • 2019 Characterization and modeling of the mechanical behavior of PE-vitrimers for pressure piping applications HUANG Tianqi
  • 2018 Conception et optimisation d'un matelas de ballistocardiographie Claude-Elvire KENGOUM PEDIE
  • 2017 Prediction and modeling of the mechanical properties of dental composites - experimental, theoretical, and numerical approach BOUSSÈS Yoan
  • 2015 Development of digital tools to assist in the design of implants for reconstructive surgery BERTO Christophe
  • 2015 Experimental and digital toolbox for the development of more sustainable dental composites AGBOBADA Gerry
  • 2014 Caractérisation mécanique et modélisation numérique des tissus de valve aortique Colin LAVILLE
  • 2010 Étude pour l’optimisation du soudage par électro-fusion des tubes et des accessoires en polyéthylène Ziad CHEBBO
  • 2009 Évaluation de la modification des contraintes biomécaniques articulaires mandibulaires au cours de la distraction symphysaire Charles SAVOLDELLI
  • 2008 Modélisation numérique de l’os mandibulaire appliquée à l’implantologie dentaire et maxillo–faciale Guillaume ODIN
  • 2006 Étude numérique et expérimentale du comportement mécanique des implants mammaires Hicham DAANOUNI
  • 2005 Développement d’un modèle éléments finis 3D appliqué à la simulation d’opérations chirurgicales des tissus mous Audrey PACCINI