Ongoing research projects

IMMC

Ongoing research projects in iMMC (November 2021)


This a short description of research projects which are presently under progress in iMMC.
Hereunder, you may select one research direction or choose to apply another filter:

Biomedical engineering

Computational science

Civil and environmental engineering

Dynamical and electromechanical systems

Energy

Fluid mechanics

Processing and characterisation of materials

Chemical engineering

Solid mechanics


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List of projects related to: finite elements




Modeling and simulation of water electrolysis.
Researcher: Christos Georgiadis
Supervisor(s): Joris Proost

The main objective of our work is to develop models for the simulation of 2-phase flows through electrodes. After the initial validation of the model, we will perform a detailed analysis of the flow and electrochemical properties of the system, in conjunction with experimental data. The final objective will be the design of optimal electrode geometries for water electrolysis.



Curvilinear mesh adaptation
Researcher: Amaury Johnen
Supervisor(s): Jean-François Remacle

graduated as a physician engineer at the University of Liège (Belgium) in 2011. Then he accomplished a PhD in the topic of quadrangular mesh generation and cuvilinear mesh validation, under the supervision of professor Christophe Geuzaine. He started a postdoctoral research in January 2016 under the supervision of professor Jean-François Remacle for working on curvilinear mesh generation, hex-dominant mesh generation and mesh validation.



Hextreme
Researcher: François Henrotte
Supervisor(s): Jean-François Remacle

completed his Engineering Degree in 1991 and his PhD in 2000, both at the University of Liège in Belgium. He then spent 4 years at the Katholieke Universiteit Leuven and 6 years at the Institut für Elektrische Maschinen in Aachen, Germany, and is now with the UCL and the ULiège. Developer in the open-source packages Gmsh, GetDP and Onelab, he has also developed skills in the multiphysics simulation of electrical machines and drives. His main interests are finite element analysis, numerical modeling, electromechanical coupling, material properties (hysteresis, iron losses, superconductors), applied mathematics (differential geometry, algebraic topology, convex analysis, dual analysis, energy methods), multiscale methods, sensitivity and optimization.



Poly-cube decomposition of 3D volumes
Researcher: Jovana Jezdimirovic
Supervisor(s): Jean-François Remacle

The aim of the research thesis is to push forward the state-of-the-art of mesh generation and propose for the first time a methodology that allows to automatically create structured multi-block meshes for general 3D domains. For that, an innovative approach that enables automatic decomposition of a general 3D domain into “poly-cubes” is proposed. A “poly-cube” map is a mechanism that allows a seamless parameterization of a 3D domain. The “poly-cube” decomposition provides the multi-block structure that is needed for structured meshing. In order to achieve this goal, the first part of the thesis is dedicated to the development of a “poly-quad” decomposition of a general 2D surface. It is relied on solving adequate Ginzburg Landau equations in order to develop a robust procedure that generates cross fields and locates critical points. Existence and location of critical points – represented as elliptic Fekete points are proved in recent results by Jezdimirovic, 2017. Further, critical points will be connected through the integral lines leading to an automatic decomposition of the domain into “quadrilaterals”. In the next step, the presented idea will be extended to 3D in order to create automatic algorithm for the “poly-cube” decomposition of 3D volumes.



BIODEC, STOCC
Researcher: Audrey Favache
Supervisor(s): Thomas Pardoen

obtained a PhD degree in the domain of process control in 2009 at Université catholique de Louvain (Belgium), after having graduated there as chemical engineer in 2005. Since then, she is working as a "senior" researcher on several applied research projects in collaboration with the industry in the domain of mechanics of materials. More particularly, she is interested in the link between the mechanical properties of the individual components of a complex system and the global mechanical response of this system. She applied this approach to the framework of tribology and contact mechanics for understanding the scratch resistance of coatings and multilayered systems. Her work covers both experimental aspects and finite element simulations.



3D crossfield generation for multibloc decomposition
Researcher: Alexandre Chemin
Supervisor(s): Jean-François Remacle

The aim of the project is to realize multibloc decomposition of 3D volumes in order to generate full hex meshes. Nowadays, this kind of decomposition is done by hand. The purpose of this work is to be able to do it in an automatic way. In order to reach this objective, we are generating 3D crossfields in this volume to locate singular points and automatize the decomposition.



On a chip fracture mechanics test method
Researcher: Sahar Jaddi
Supervisor(s): Thomas Pardoen

The aim of this research is to develop a new testing method based on an-on-chip concept to measure the fracture toughness of freestanding submicron films. This device consists of two major components, a notched specimen and two actuators. When the test structure is released by etching the sacrificial layer, the two actuators contract, this in turn loads the specimen in traction. In order to define the stress intensity factor expression, which is given by this new model, analytical analysis and finite element simulations must be performed in addition to the experimental part, which is based on the microfabrication techniques. Silicon nitride, silicon oxide and metallic glass thin films will be studied during this work. The major goal of this model is to extract fracture toughness of 2D materials like graphene.



Improving the properties of glass fiber reinforced acrylic thermoplastic resin based composites
Researcher: Sarah Gayot
Supervisor(s): Thomas Pardoen

For the manufacturing of continuous fiber reinforced thermoplastic composites (CFRTP), certain monomers can be infused through glass fabric and then polymerized in situ, in order to make a thermoplastic composite part. However, defects - e.g. porosity - can occur in the material, due to the thickness of the laminates and the shrinkage of the resin matrix during polymerization. Such phenomena must be understood, as well as their effects on the mechanical properties of the final composite part.

The originality of this work lies in the very nature of the polymeric matrix used for manufacturing the composite parts, which is thermoplastic instead of thermoset. Little is known about the behaviour of such thermoplastic composites, especially at a microscopic scale. During this PhD, we will try to understand how defects occurring in the material can influence the structural properties of the CFRTP, and we will try to mitigate (or at least control) the incidence of such defects. This will imply a better knowledge of how usual characterisation techniques can be applied from thin to thick composite parts. In particular, digital simulation will be used so as to predict the properties of thick composite parts from those of thinner samples.



Optimization of tensegrity bridges based on morphological indicators
Researcher: Jonas Feron
Supervisor(s): Pierre Latteur

Tensegrity structures are composed of struts and tendons in such way that the compression is “floating” inside a net of tension in a stable self-equilibrated state. Although tensegrity forms have inspired artists and architects for many years, there exist very few real construction projects across the world. The main reasons are, among others, the complex construction processes and the lack of design guidelines. This research, performed in collaboration with the company BESIX, aims at proving the feasibility of a first pure tensegrity bridge around the world.
When the structure is externally loaded, large displacements occur and require non-linear calculation before reaching an equilibrium. Indeed, in tensegrity structures more than in conventional ones, form and forces are intrinsically correlated. This phenomenon is due to their intern mechanism, unless appropriate pre-stressing is applied. An allowable stiffness can be possible, but at a certain material cost, which in turn justifies the relevance of the optimization of the weight.
While designing a tensegrity structure, optimization and form finding are often great challenges. Indeed, the large amount of parameters (span, height, shape, cross sections, materials, loads, pre-stress, etc) makes the search for the structure with the best performances cumbersome. A solution to this problem is to reduce the number of degrees of freedom to consider, by grouping them into dimensionless numbers, the morphological indicators.
In 2014, R.E. Skelton et al were pioneers in using a similar approach for optimizing planar tensegrity bridges uniformly loaded. In 2017, P. Latteur et al adapted the morphological indicators methodology, used so far to optimize mainly trusses and arches, to 3D non-linear and pre-stressed lattice structures such as tensegrity structures. In 2019, J. Feron et al used this methodology to investigate the performances of different 3D forms of uniformly loaded tensegrity footbridges.
This research focus on the required checks to ensure the practicality, the constructability and the economical and structural efficiency of a pure tensegrity footbridge thanks to non linear finite element analysis, experimental validation, parametric design, prestress optimization and dynamic behavior assessment