MASSIF : MAcroScopic SImulation of Fibrous materials

MASSIF: MAcroScopic SImulation of Fibrous materials

Unlike fluids for which a number of numerical models have been proposed, complex divided materials such as fibrous media remain less studied from a macroscopic point of view: there is currently no well-accepted numerical model for capturing the dynamics of entangled materials in a predictive way. The industrial demand has however been strongly increasing these latest years, encompassing the fields of cosmetology (fine prediction of hair mechanical behavior), virtual entertainment (simulation of hair and fur for special effects), or virtual prototyping in mechanical engineering (cables entanglement, composite materials).

Coordinators: F. Bertails-Descoubes (Inria-LJK), P. Saramito (LJK), B. Raffin (Inria-LIG)

Web site: https://persyval-lab.org/en/exploratory-project/massif-macroscopic-simulation-fibrous-materials

Results: the exploratory project MASSIF has launched a first and decisive impulse for starting this long-term research project around the macroscopic modelling of fibrous materials. In particular, this project gave us the unique opportunity to hire Gilles Daviet as a PhD student (funded by Persyval from 2013 to 2016) to pursue our first studies on the topic. Gilles Daviet’s PhD thesis started with an exhaustive state-of-the-art on existing models for fiber assemblies; then we have focused on a simplified but still longstanding challenge: that of designing a numerical model for macroscopic granular flows, able to capture nonsmooth stick-slip transitions occurring between grains. The corresponding constitutive law, known as the Drucker-Prager law, was usually regularized by previous approaches, then losing some key emerging effects in the dynamics of the flow, such as stable stacking. Gilles Daviet’s PhD work showed that it was not only possible to preserve nonsmoothness of the law numerically, but also to solve the resulting one-step problem in an efficient manner by adapting existing solvers from discrete frictional contact problems. This pluridisciplinary work led to 2 journal publications [1,2], as well as several communications and posters at various conferences ranging from mechanics and physics to computer graphics. All the corresponding source code was delivered freely under the GNU GPL License. The PhD thesis was awarded the PhD prize 2017 from the GdR "Informatique Géométrique et Graphique, Réalité Virtuelle et Visualisation", see https://prixigrv2017.sciencesconf.org/

More information is available here: http://bipop.inrialpes.fr/people/gdaviet/

Selected publications:

[1] G. Daviet, F. Bertails-Descoubes, A Semi-Implicit Material Point Method for the Continuum Simulation of Granular Materials, ACM SIGGRAPH 2016.

[2] G. Daviet, F. Bertails-Descoubes, Nonsmosoth simulation of dense granular flows with pressure-dependent yield stress, JNNFM 2016.