vriphys14
https://diglib.eg.org:443/handle/10.2312/7754
ISBN 978-3-905674-71-22024-03-28T17:28:16ZParallel Particles (P2): A Parallel Position Based Approach for Fast and Stable Simulation of Granular Materials
https://diglib.eg.org:443/handle/10.2312/vriphys.20141232.135-144
Parallel Particles (P2): A Parallel Position Based Approach for Fast and Stable Simulation of Granular Materials
Holz, Daniel
Jan Bender and Christian Duriez and Fabrice Jaillet and Gabriel Zachmann
Granular materials exhibit a large number of diverse physical phenomena which makes their numerical simulation challenging. When set in motion they flow almost like a fluid, while they can present high shear strength when at rest. Those macroscopic effects result from the material's microstructure: a particle skeleton with interlocking particles which stick to and slide across each other, producing soil cohesion and friction. For the purpose of Earthmoving equipment operator training, we developed Parallel Particles (P2), a fast and stable position based granular material simulator which models inter-particle friction and adhesion and captures the physical nature of soil to an extend sufficient for training. Our parallel solver makes the approach scalable and applicable to modern multi-core architectures yielding the simulation speed required in this application. Using a regularization procedure, we successfully model visco-elastic particle interactions on the position level which provides real, physical parameters allowing for intuitive tuning. We employ the proposed technique in an Excavator training simulator and demonstrate that it yields physically plausible results at interactive to real-time simulation rates.
2014-01-01T00:00:00ZAn Improved Jacobi Solver for Particle Simulation
https://diglib.eg.org:443/handle/10.2312/vriphys.20141231.125-134
An Improved Jacobi Solver for Particle Simulation
Frâncu, Mihai; Moldoveanu, F.
Jan Bender and Christian Duriez and Fabrice Jaillet and Gabriel Zachmann
This paper presents a new method for simulating particles for computer graphics and video games, based on an improved Jacobi solver and a hybrid approach between velocity time stepping and position based dynamics. Current constrained dynamics solvers use relaxation iterative methods like Gauss-Seidel or Jacobi. We propose a new iterative method based on a minimum residual variant of the Conjugate Gradient algorithm and show that it can be formulated as an improvement to the Jacobi method. We also describe an adaptation of position based dynamics to better handle contact and friction and allow tight two way coupling with velocity level methods.
2014-01-01T00:00:00ZA Parallel Architecture for IISPH Fluids
https://diglib.eg.org:443/handle/10.2312/vriphys.20141230.119-124
A Parallel Architecture for IISPH Fluids
Thaler, Felix; Solenthaler, Barbara; Gross, Markus
Jan Bender and Christian Duriez and Fabrice Jaillet and Gabriel Zachmann
We present an architecture for parallel computation of incompressible IISPH simulations on distributed memory systems. We use orthogonal recursive bisection for domain decomposition and present a stable and fast converging load balancing controller. The neighbor search data structure is derived such that it optimally fits into the parallel pipeline. We further show how symmetry aspects of the simulation can be integrated into the architecture. Simultaneous communication and computation are used to minimize parallelization overhead. The seamless integration of these parallel concepts into IISPH results in near linear scaling for large-scale simulations.
2014-01-01T00:00:00ZCoupling Hair with Smoothed Particle Hydrodynamics Fluids
https://diglib.eg.org:443/handle/10.2312/vriphys.20141229.109-117
Coupling Hair with Smoothed Particle Hydrodynamics Fluids
Lin, Wei-Chin
Jan Bender and Christian Duriez and Fabrice Jaillet and Gabriel Zachmann
We present a two-way coupling technique for simulating the complex interaction between hair and fluids. In our approach, the motion of hair and fluids is simulated by evaluating the hydrodynamic forces among them based on boundary handling techniques used in SPH (Smoothed Particle Hydrodynamics) fluids. When hair makes contact with fluids, water absorption inside the hair volume can be simulated with a diffusion process by treating the hair volume as porous media with anisotropic permeability. The saturation of each hair strand is then used to derive the adhesive force between wet hair strands. This enables us to simulate the formation of hair clumps dynamically without the need to employ post clumping processes. The proposed method can be easily applied to any SPH fluid solvers as well as various hair models.
2014-01-01T00:00:00Z