The properties and behavior of macrocale systems originate from phenomena occurring at significantly smaller temporal and spatial scales. Classical simplifications of atomic interactions, like force field, might not be sufficient, especially when quantum effects become significant. Through the FNR project Quantum Continuum Coupling (QuaC), we are collaborating with Prof. Alexandre Tkatchenko and his TCP group to incorporate quantum mechanics approximations into large-scale and multsicale modeling for material simulations. We are particularly interested in the many-body van der Waals effects on the mechanical properties of certain engineering materials, such as ultra-high-molecular-weight polyethylene (UHMWPE) and polymer melts.
Team
PI: Prof. Stéphane Bordas (Legato), Prof. Alexandre Tkatchenko (TCP)
Postdoc researcher: Dr. Jakub Lengiewicz (Legato)
PhD researcher: Zhaoxiang Shen (Legato), Raul Ian Sosa (TCP)
Reference
A. Tkatchenko, R. A. DiStasio, R. Car, and M. Scheffler. Accurate and efficient method for many-body van der waals interactions. Phys. Rev. Lett., 108:236402, Jun 2012.
P. Hauseux, T.-T. Nguyen, A. Ambrosetti, K. Saleme Ruiz, S.P.A. Bordas, and A. Tkatchenko. From quantum to continuum mechanics in the delamination of atomically-thin layers from substrates. Nature Communications, 11(1):1651, 2020.
This thesis deals with the study of residual stresses in a polymer matrix composite part obtained using the High Temperature Fused Deposition Modeling (HT-FDM) manufacturing process. This type of 3D printing uses high performance polymers as the primary material. During the printing process, several types of defects are observed due to the strong thermal gradient that the part under construction undergoes, generally representing the lack of dimensional accuracy with respect to the 3D model used to encode the printing paths. This distortion is in fact a residual deformation associated with residual stresses in the part in response to the temperature distribution during printing until each point of the material reaches room temperature.
Team
PI: Prof. Stéphane Bordas (Legato), Prof. Noël LAHELLEC (AMU)
Research associated: Dr Aurélien MAUREL-PANTEL (AMU), Dr Djaffar Boussaa (AMU), Dr Hervé MOULINEC (AMU)
Postdoc researcher: Dr. Remy Cornaggia (Sorbone-France)
PhD researcher: Camilo Andrés SUAREZ AFANADOR (Legato/AMU)
Reference
C.A. Suarez-Afanador, R. Cornaggia, N. Lahellec, A. Maurel-Pantel, D. Boussaa, H. Moulinec, S.P.A. Bordas. Effective thermo-viscoelastic behavior of short fiber reinforced thermo-rheologically simple polymers: An application to high temperature fiber reinforced additive manufacturing. European Journal of Mechanics - A/Solids, 96:104701, 2022.
Camilo A. Suarez-Afanador, Noel Lahellec, Martín I. Idiart. Mean-field descriptions for the viscoelastic response of thermorheologically complex reinforced solids. European Journal of Mechanics - A/Solids, 98:104859, 2023.
Modern industry grapples with the stochastic nature of solids inherent by features and imperfections of the geometry, material properties, boundary and loading conditions. This often is the main cause of instability issues such as buckling, post-buckling regimes in solid structures, fracture nucleation, and propagation, and many others. Predicting such instability behaviour proves challenging with conventional mathematical models, impeding the fabrication of solids with desired properties. Presently, solid design predominantly relies on traditional deterministic methodologies that overlook these instabilities in behaviour, or capture them through overly conservative factors of safety. However, contemporary uncertainty quantification methods provide various techniques to capture stochastic behaviour. This PhD project is dedicated to the development of cutting-edge numerical methods for uncertainty quantification, aiming to comprehend the functional stochastic behaviour of instability problems in solid mechanics.
Key-words: uncertainty quantification, instability problem, solid mechanics, automated finite element solvers, FEniCSx
Team
Collaborators: Dr. Jack S. Hale (Legato), Prof. Corrado Maurini (Sorbonne Université, France)
PhD researcher: Andrey Latyshev (Legato)
Project 2 description