Institution: Icam School of Engineering (Icam Lille) and University of Lille (ULille)
Thesis Supervisors: Prof. Fahmi ZAIRI (LGCgE-ULille) and Dr. Karim KANDIL (Icam Lille and LGCgE-ULille)
Laboratory: Laboratoire de Génie Civil et géo-Environnement (LGCgE) – ER1: Multi-scale modeling and characterization of coupled problems
Description of the project
For a precise creation of numerical models of intervertebral discs, the modeling strategy must be based on a reliable and realistic relationship between microstructure, morphology, and intrinsic mechanical features (including strong non-linearity, viscosity, and anisotropy), while considering the regional effect, the coupling with the surrounding biochemical environment, and the degeneration mechanisms whether they are of mechanical and/or biological origin.
The objective is to ultimately propose advanced calculation methodologies for a better understanding of the effect of age and degeneration on the response of the different discs of the vertebral column. This thesis project is based on the experimentation/modeling/simulation triptych making it possible to develop a physically based modeling approach, based on experimental observations, to verify its predictive capacities and to use the simulation tool in various configurations of mechanical loadings.
Initially, the candidate will characterize in vitro intervertebral disc tissues under various multi-axial loading conditions (monotonic and cyclic) and environments.
The candidate will then participate in elaborating a new constitutive model that directly links the microstructure and the mechanical response of the disc based on a multi-scale approach formalized in the framework of continuum mechanics. The model will consider the different multiphysics coupling mechanisms associated with the chemo-mechano-biological response of the disc.
This work will be followed by the implementation of the constitutive model into a finite element code and its experimental verification at different scales (the monolayer microstructural scale, the regional multilayer scale, and the scale of a complete intervertebral disc) under various multi-axial loading (monotonic and cyclic) and environmental conditions. This multi-scale verification will ensure the most realistic possible reproduction of the mechanical behavior of the intervertebral disc in relation to its regional microstructure.
- Phase 1 (Experimental): In vitro experimental analysis of the mechanical response of the soft tissues of the intervertebral disc under different loading conditions.
- Phase 2 (Constitutive modeling): Development of a multiphysics and multiscale constitutive model of the soft tissues of the intervertebral disc.
- Phase 3 (Simulation): Implementation of the constitutive model into a finite element code and creation of numerical models of samples and functional units of the spinal column from MRI scans of real patients.
- Phase 4 (Tool verification): Numerical/experimental comparison and validation of the predictive capabilities of the simulation tool.
- Phase 5 (Optimization): Optimization of the developed tool in order to reproduce personalized models of the disc. Performance of practical cases in real situations to predict degenerative evolution under given loading and degradation scenarios.
The thesis will take place primarily at the LGCgE and the Icam (Lille headquarter).
The candidate must hold a master’s degree or an engineering degree in mechanics, biomechanics, materials science, or equivalent. Good knowledge of continuum mechanics and mechanics of materials. Good command of programming tools (Matlab and/or Fortran). Scientific rigor and excellent writing skills. Good level of English proficiency. A first experience in numerical and/or experimental analysis of materials would be appreciated.
Application and information
Please send your CV + latest transcript of records + motivation letter + recommendations (letters or contact information) to: Fahmi ZAIRI – Email: Fahmi.Zairi@polytech-lille.fr and Karim KANDIL – Email: Karim.Kandil@icam.fr
Application deadline: May 17, 2023.