Consultation des offres
Thèse: Application of the numerical tools on the stability analysis and optimization design of 3D printed concrete structure CDD
Supervisors : S. Rémond, D. Hoxha, D.P. Do
Period : 36 months from Septembre 2020 to August 2023
Laboratory : Lamé, EA 7494, Université d’Orléans, 45072 Orléans Cedex 2.
Keywords : 3D printing technique, concrete structure, numerical tools, stability analysis, optimization design, fresh concrete, elasto-visco-plastic behavior
The 3D printing technique has largely developed in the last decade with high potential application in many industrial fields. In Civil Engineering, concrete 3D printing has been considered as a low cost and high-speed construction technique. Applicable to different structural forms, this method gives a high flexibility for architectural design. Despite its high advantage, the knowledge on the mechanical behavior of the 3D printed concrete structure during and after the printing process seems quite limited. The influence of the fresh concrete behavior on the stability of structure during printing remains an open question. Another challenge lies in the optimization strategy to find out the most appropriate printing parameters like speed, layer size,… corresponding to the 3D printed structural form.
Objective and content of the thesis
The principal objective of this works is to provide, through numerical modelling, design tools and/or procedures for stability analysis of 3D printed concrete structures from the moment where the concrete is layered out (fresh concrete and structure behaviour) to the hardened ones. On one hand this implies modelling of material behaviour (fresh and hardened concrete used in 3D printing) and on the other hand modelling of the printed structure during and after 3D printing process. The work consists firstly of selecting/adopting or eventually developing a constitutive model to describe the thixotropic behaviour of the fresh concrete. This model should be simple and accessible for industrial use. The essential mechanical properties of the fresh and hardened concrete model should be calibrated through simple tests following existing or new developed in laboratory or in field procedures. These tests will be performed by partners of the project, but a contribution of this Ph.D.is attended on the interpretation of tests and identification of model parameters.
The models for fresh and hardened concrete adapted/adopted/developed and calibrated as mentioned above, will be implemented in an appropriate software for modelling of concrete structures during printing and after concrete hardening. The objective of printing process modelling is to analyse the stability of structures and to optimise (in interaction with architects) the shape and the geometry of the structure against the buckling. It is thought that besides the geometry of the structure, the printing parameters (e.g. printing speed, layer dimensions, …) for a given concrete formula are important parameters whose impact in structure buckling should be studied. Similar problems for analysis and optimisation design rise also for the post-printed hardened-concrete structures. It is necessary to check through numerical modelling whether standard rules for concrete structures could/should be applied for printed ones, and eventually propose alternative specific design procedures. For both phases of structure modelling (during printing and after concrete hardening) the numerical strategy consists of combining a Computer-Aided Design (CAD) tool with a suitable structure analyses software running in a High-Performance Computing (HPC) centre (CaSciModOT) in order to deal with a huge number of degrees of freedom problem, inherent to 3D modelling. For optimization design and selecting appropriate range of each printing parameter, as well as for the evaluation of design of hardened concrete, the adoption/development of a performant artificial intelligence technique will be considered.
Master in Civil Engineering, materials, solid mechanics, numerical modelling.
The candidate must have a solid background on mechanics of materials, constitutive modelling, structure mechanics, numerical computing.
How to apply :
- Application deadline : Jully 1st 2020
- To be submitted to : firstname.lastname@example.org, email@example.com and firstname.lastname@example.org
- The application should include : a detailed CV, a cover letter, transcripts of the master degree
- Comportement physique et mécanique