Received: 5 November 2015 Revised: 24 February 2018 Accepted: 9 March 2018
Coupling of material point method and discrete element
method for granular flows impacting simulations
Gordon G.D. Zhou
State Key Laboratory of Hydroscience
and Engineering, Tsinghua University,
Department of Civil and Environmental
Engineering, Princeton University,
Princeton, NJ, USA
Institute of Mountain Hazards and
Environment, Chinese Academy of
Sciences, Chengdu, China
Qicheng Sun, State Key Laboratory of
Hydroscience and Engineering, Tsinghua
University, Beijing, China.
National Natural Science Foundation of
China, Grant/Award Number: 11572178
Granular debris flows are composed of coarse solid particles, which may be
from disaggregated landslides or well-weathered rocks on a hill surface. The esti-
mation of agitation and the flow process of granular debris flows are of great
importance in the prevention of disasters. In this work, we conduct physical
experiments of sandpile collapse, impacting 3 packed wooden blocks. The flow
profile, run-out distance, and rotation of blocks are measured. To simulate the
process, we adopt a material point method (MPM) to model granular flows and
a deformable discrete element method (DEM) to model blocks. Each block is
treated as comprising 9 material points to couple the MPM and DEM, and the
acceleration of grid nodes arising from the contacts between granular material
and blocks is projected to the discrete element nodes working as body forces.
The contacts between blocks are detected using the shrunken point method.
The simulation results agree well with the experimental results. Thus, the cou-
pling method of MPM and DEM developed in this work would be helpful in the
damage analysis of buildings under impact from the debris flows.
discrete element method, granular flows, impacting estimation, material point method
Debris flows are massive motions of solid particles from mountainous areas and steep hillslopes to valleys and river
channels. In recent years, the major components of debris flows in mountainous regions in China are boulders, gravel,
and sand, and these debris flows may be termed as granular debris flows, which exhibit different mechanical properties
from common mudflows composed of clay-sized particles. For example, following the devastating 2008 earthquake in
Sichuan province, China, several severe debris flows have already claimed many additional lives.
A million people in this
region continue to be affected as earthquake-induced destabilization of local slopes will result in high rates of additional
postearthquake debris flows over the next several decades. It is important to be able to predict the travel distances and to
estimate the impacting influences of granular debris flows. An improved predictive science-based framework for debris
flows is urgently needed for hazard mitigation.
The agitation and flow of the disaggregated landslide involve large deformation problems.
In the general sense, it is
difficult to use a classical mesh-based method such as the finite element method to model behaviors involving large defor-
mations due to severe mesh distortion errors, which ultimately requires remeshing.
To overcome this difficulty, several
mesh-free methods such as smoothed particle hydrodynamics
and material point method (MPM)
have been proposed.
172 Copyright © 2018 John Wiley & Sons, Ltd. wileyonlinelibrary.com/journal/nme Int J Numer Methods Eng. 2018;115:172–188.