Speaker: Mr. Ehsan Izadi
Doctoral Researcher
Ghent University
Title: Physics Engines: an Advancement in the Granular Simulations in Geotechnics
Local Organizer: Dr. Mohammad Mehdi Ahmadi
Time: Monday, September 7, 2015, 12:00
Location: Room no. 202, Department of Civil Engineering, Sharif University of Technology
Abstract:
Physics engines are software which firstly have been developed for gaming and animation purposes,
and provide simulation of rigid and soft bodies as well as fluid. The main advantages of using physics engines in granular simulation are the highly optimized algorithm and also the sharing capability of computational load on GPUs, which makes them significantly faster than the conventional CPU-based discrete element (DEM) approaches in granular mechanics. It is important to note that currently very few DEM softwares have the capability of running on GPU.
Physics engines use contact dynamics (CD) (also referred to as rigid body dynamics) method for calculation of forces and displacements of rigid body systems. CD is a non-smooth discrete element method in which small elastic response times and the relevant deformations are neglected and their influence is absorbed into the contact laws. This enables CD calculations to advance at a several orders of magnitude larger of time step compared to that of common DEM approach. Conceptually, CD aims to solve granular problems at “meso-scale†rather than focusing on purely micro-scale problems, as common DEM does. However, like DEM methods, the effect of granules shape and size can be considered in the global behaviour of the granular media.
Several cases of granular simulations using physics engines have been investigated up to now such as pluviation and vibration of cylinder filled with granular material. In the figure below, the simulation of a direct shear test on dense and loose samples is demonstrated along with relevant results. More discussion on simulations will be presented at the symposium.