PhD Position Modelling of curly hair

PhD Position F/M Modelling of curly hair

Fonction : Doctorant

Staff is present on three campuses in Grenoble, in close collaboration with other research and higher education institutions (Université Grenoble Alpes, CNRS, CEA, INRAE, …), but also with key economic players in the area.

The Centre Inria de l’Université Grenoble Alpes is active in the fields of high-performance computing, verification and embedded systems, modeling of the environment at multiple levels, and data science and artificial intelligence. The center is a top-level scientific institute with an extensive network of international collaborations in Europe and the rest of the world.

Over the last 30 years the graphics community has actively worked on the simulation of dense fibrous assemblies such as human hair or animal fur. Whether it is for the realistic animation of characters by the entertainment industry, for its applications in cosmetology, or for the design of mechanical structures, simulating accurately such kinds of systems remains challenging and computationally costly.

Furthermore, a rich underlying phenomenology arises from the interaction between fibers, driven by the interplay between geometry, frictional contact, and elasticity. Due to the large number of degrees of freedom and the strong coupling between the length-scales at which fibers interact, innovative approaches are crucial.

Recent developments for the simulation of frictional fibers have made possible the efficient simulation of tens of thousands interacting fibers producing visually appealing images. However, these simulators remain limited to fibers with small natural curvature, making them unable to retrieve the rich phenomenology observed for highly curly fibers. Additionally, in many cases, the underlying model for the simulation is not systematically tested for its validity.

To bring a breakthrough on the realistic simulation of frictional fibers, we believe that a combined effort between computer simulation, physics and mechanics is required. While computer simulation has developed a large amount of knowledge to efficiently solve large-scale problems numerically, physics and mechanics have a long-standing culture to model and analyse complex systems through controlled experiments and theoretical developments. Progressively, these communities are joining their forces to, on the one end, produce more realistic physics-based simulators, and on the other end, find model configurations to study the physical validity of simulations and advance the understanding of physical systems with enhanced complexity.

Objectives

While studies exist regarding the mechanics and shape characterisation of a single curly hair, extensions to the understanding and modelling of a full collection of curly filaments in 3D remains scarce.

The objective for this PhD position is to combine our current numerical and experimental works on fiber assemblies to better understand and model, at the macro-scale, some remarkable collective phenomena appearing in curly hair due to the mixed effects of elasticity/geometry and frictional contact at the fiber scale.

This work will take advantage of the numerical Kirchhoff models for rods, contact detection, and frictional contact solvers developed by the Elan team, and additionally, we expect for this study to have an important experimental component to conceive novel setups and collect data to compare with simulations.

The candidate is expected to hold an M2 degree (Engineering degree, MRes, or equivalent) in applied mathematics or informatics. The candidate should have some experience in either:

• In a computer simulation related topic (Computer Sciences, Computer Graphics, Engineering, or Applied Mathematics) with strong expertise in numerical simulation, mathematical modelling, and software development; taste and skills in physical modelling and experiments will be appreciated.
• In a mechanics related topic (Mechanics, Physics, or Engineering) with expertise either in experimental or theoretical research; taste and skills in programming will be appreciated.

All candidates should have a good understanding in numerical analysis (modelling,…