This page highlights some research and projects that I have been involved in the past. Some of them are successfully published as journal articles and conference proceedings, which can be found in the Publications page.

Material Point Method (MPM)

A coupled stabilized ISPH-DEM scheme for fluid-rigid-body simulations

Collaborators: Prof. Mitsuteru Asai, Yi Li (Kyushu University)

With a motivation to simulate water-induced natural hazards accurately, a fluid-structure coupled simulation tool is developed employing particle-based methods. The incompressible Smoothed Particle Hydrodynamics (ISPH) method is chosen to model the fluid flow, whereas the rigid body is modeled by using a particle-based Discrete Element Method (DEM). A stabilized ISPH proposed by Asai et al. 2012 is used as it has been proven to produce a smooth and accurate pressure distribution of free-surface fluid flow with breaking and fragmentation. Upon solving the fluid pressure field through an operator splitting approach, the hydrodynamic forces can be applied onto solid objects through SPH kernel averaging technique. At the same time, the rigid bodies may simultaneously experience contact with other objects and boundaries. Modeled by using DEM, the contact force between these rigid bodies can be approximated by employing either the penalty or the impulse-based methods. Our work has focused on developing an ISPH-DEM coupled algorithm, which exhibits higher accuracy, stability, and efficiency. The developed software has been validated and used for simulations of bridge-washout phenomena, which frequently occur during tsunami, as well as debris flow problems.

Accurate modeling of collision response in DEM and multiple-rigid-body simulations

Collaborators: Prof. Mitsuteru Asai, Yi Li (Kyushu University)

Simulations of multi-body dynamics for computer graphics, 3D game engines, or engineering simulations often involve contact and articulated connections to produce plausible results. As higher accuracy and robustness are continually being sought for engineering purposes, an improved multi-body dynamics simulator based on an impulse method is proposed, specifically an energy-tracking impulse (ETI) algorithm that has been modified to handle particle-discretized rigid-body simulations. To decrease the computational costs of the simulations, a fixed moderate time increment is assumed, allowing multiple-point contacts within a single time increment. The treatment between point-to-point and multiple-point contacts, which include edge-to-surface and surface-to-surface contacts, are, therefore, distinguished through an additional sub-cycling iterations to ensure the conservation of energy.

Other projects

Some previous short-term research and course projects related to numerical method and its application.