Title: Simulation of Granular Flow using the Material Point Method

Author (Talk): Sachith Dunatunga, MIT

Abstract:

The material point method (MPM) is a meshfree method which uses mobile Lagrangian markers known as material points to store the state of the body, while solving the equations of motion on a background grid. By resetting this grid at the beginning of each timestep, MPM is able to solve problems with large inhomogeneous deformations while retaining the ability to reproduce elastic behavior when static, combining the strengths of both computational fluid dynamics and basic finite element methods. We have implemented an MPM solver for 2D problems. Using first order elements and a local model for granular flow, simulations such as collapse of a sand pile and discharge of a silo produce the physically expected behavior even when the strains become extremely large. Particularly, Beverloo scaling is recovered in the silo. A linearized version of the local model is used in the solution of a nonlocal model, which has been confirmed to reproduce reference results in the vertical chute geometry. We are currently investigating implementation of the non-linearized nonlocal model, which involves solving a stiff diffusion-like set of equations coupled with the original equations of motion.