12 Juillet – Soutenance HDR Anita Catapano

09 h30 ECOLE ENSEIRB-MATMECA à Talence - Amphi F et lien Zoom ci-dessous

"Multiscale models to design anisotropic and heterogeneous media"

Résumé

The accurate design of anisotropic and/or heterogeneous structures requires the development of specific models capable of correctly simulating the physical behaviour of the structure and of the material. At the same time, these models must be efficient, in terms of both quality of results and computational costs, to be integrated into design/optimisation strategies. However, the simulation of the physical behaviour of complex media presents several difficulties to be taken into account, i.e. the heterogeneity and the anisotropy, that intervene at different scales of the problem and that could also vary point-wise over the structure. Another aspect concerns the properties of the interfaces since the quality of adhesion influences considerably the behaviour of the material. In this context, the development of suitable mathematical representations of anisotropy and homogenisation techniques is of fundamental importance.

To this end, the HDR manuscript pays particular attention to the development of analytical models and tensor invariants-based representations able to simplify the analytical/numerical models without degrading the quality of results. In this context, four research topics are discussed:

- The development of multi-scale models based on tensor invariants for the optimization of variable stiffness laminates obtained from additive manufacturing. Tensor invariants represent an established analytical reduced model which allows considerably simplifying the problem formulation and reducing the related computational costs without introducing simplifying hypotheses. Here, the focus is put on the generalisation of tensor invariants-based representations to the description of strength in anisotropy;

- The development of a design strategy for ad-hoc composite specimens that could enable to highlight specific damage mechanisms eliminating couplings and undesired parasite effects typical of composite laminates. To this purpose, tensor invariants-based models have been exploited to derive analytical rules to design multi-directional layups for delamination tests;

- The generalisation of semi-analytical homogenisation techniques to take into account for material and geometrical non-linearity of the constituents, like damaged interfaces (through the introduction of cohesive zones), the hyper-elastic behaviour of matrix and inclusions, the variability of physical properties (especially in bio-based composites);

- The analysis of interface models for the study of adhesion phenomena both in classical industrial applications and on surfaces manufactured by Selective Laser Melting (SLM) for biomedical implants.

The proposed modelling strategies are validated both numerically and experimentally to prove their effectiveness. Medium and long-term prospects are provided at the end of the manuscript about the generalisation of the research topics to the development of full 3D models based on smart invariants-based representations for the design of additive manufactured composites.

Composition du jury

Pedro M.P.R. de Castro Camanho, Pr., Faculdade de Engenharia da Universidade do Porto, Reviewer
Rafael Estevez, Pr., SIMaP, Université Grenoble Alpes, Reviewer
Djimedo Kondo, Pr., D'Alembert, Université Pierre et Marie Curie, Reviewer
Olivier Allix, Pr., LMT, ENS Paris-Saclay, Examiner
Heng Hu, Pr., School of Civil Engineering, Wuhan University, Examiner
Jean-Francois Maire, Dr., ONERA Châtillon, Examiner
Eric Martin, Pr., LCTS, Bordeaux INP, Examiner
Thierry Palin-Luc, Pr., I2M, Arts et Métiers Sciences et Technologies, Examiner
Paolo Vannucci, Pr., LMV, Université de Versailles Saint-Quentin-en-Yvelines, Examiner

Invitation

Lien Zoom : https://bordeaux-inp-fr.zoom.us/j/81193187576

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