# Yucang WangCentral Queensland University · School of Engineering and Technology

Yucang Wang

Doctor of Philosophy

## About

77

Publications

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1,306

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Introduction

Additional affiliations

June 2014 - October 2016

February 2009 - May 2014

February 2001 - December 2008

## Publications

Publications (77)

This book is written as a textbook for engineering students who have completed courses in elementary calculus, linear algebra, and differential equations to learn programming skills in MATLAB, and subsequently to apply the programming skills for solving practical problems in engineering. It provides students with an opportunity to advance math skil...

In recent years some comparative studies have explored the use of parallel ant colony optimization (ACO) algorithms over the traditionally sequential ACOs to solve the traveling salesman problem (TSP). However, these studies did not take a systematical approach to assess the performance of both algorithms on a comparable ground. In this paper, we a...

At Central Queensland University, students enrolled in Bachelor of Engineering are predominately from regional areas, and roughly have a 60--40 percent split between on-campus and distance cohorts. The continuing mining downturn in regional areas, for the past several years, has deterred many potential students from choosing engineering as their pr...

Most engineering and scientific problems are too complicated to be solved using analytical techniques. An alternative approach is the use of numerical procedures to obtain approximations to the exact solutions. Computational modelling is an integral skill set in problem solving for engineering graduates in the current technology-driven focus of wor...

This paper developed a detailed fluid dynamics model and a parallel computing scheme for air brake systems on long freight trains. The model consists of subsystem models for pipes, locomotive brake valves, and wagon brake valves. A new efficient hose connection boundary condition that considers pressure loss across the connection was developed. Sim...

In geochemical data analysis, chemical elements are often clustered by statistical means first to reveal any established association of some elements due to similar originality, co-location, chemical bonding, or contamination. Statistical clustering ranks a predominately single association among elements very highly and the double or multiple assoc...

When the bonded discrete element models are used to model rock fracture, the compressive-tensile strength ratio and the internal frictional angle obtained from the conventional discrete element models are found to be much lower than the laboratory results. The methods to improve this include the use of non-spherical particles, and some modification...

Rolling and sliding play fundamental roles in the deformation of granular materials. In simulations of granular flow using the discrete element method (DEM), the effect of rolling resistance at contacts should be taken into account. However, even for the simplest case involving spherical particles, there is no agreement on what is the best way to d...

An outburst of coal and gas is a major hazard in underground coal mining. It is generally accepted that an outburst occurs when certain conditions of stress, coal gassiness and physical-mechanical properties of coal are met. Outbursting is recognized as a two-step process, i.e., initiation and development. In this paper, we present a fully-coupled...

Understanding the characteristics of hydraulic fracture, porous flow and heat transfer in fractured rock is critical for geothermal power generation applications, and numerical simulation can provide a powerful approach for systematically and thoroughly investigating these problems. In this paper, we present a fully coupled solid-fluid code using d...

Particle scale diffusion is implemented in the discrete element code, Esys-Particle. We focus on the question of how to calibrate the particle scale diffusion coefficient. For the regular 2D packing, theoretical relation between micro- and macrodiffusion coefficients is derived. This relation is then verified in several numerical tests where the ma...

Realizing the potential of geothermal energy as a cheap, green, sustainable resource to provide for the planet’s future energy demands that a key geophysical problem be solved first: how to develop and maintain a network of multiple fluid flow pathways for the time required to deplete the heat within a given region. We present the key components fo...

It has long been recognized that the rotation of single particles plays a very important role in simulations of granular flow using the discrete element method (DEM). Many researchers have also pointed out that the effect of rolling resistance at the contact points should be taken into account in DEM simulations. However, even for the simplest case...

The sudden and violent nature of coal and gas outbursts continues to pose a serious threat to coal mine safety in China. One of the key issues is to predict the occurrence of outbursts. Current methods that are used for predicting the outbursts in China are considered to be inadequate, inappropriate or impractical in some seam conditions. In recent...

Gas content of coal is used in gas emission estimation, and gas outburst proneness assessment in underground coal mining. The commonly used method for the estimation of the gas content is by the direct desorption method. One of the important factors affecting the accuracy of the estimation of the gas content with this method is the estimation of ga...

The analytical mathematical solutions of gas concentration and fractional gas loss for the diffusion of gas in a cylindrical coal sample were given with detailed mathematical derivations by assuming that the diffusion of gas through the coal matrix is concentration gradient-driven and obeys the Fick’s Second Law of Diffusion. The analytical solutio...

In this chapter, we present a fully coupled solid-fluid code using Discrete Element Method (DEM) and Lattice Boltzmann Method (LBM). The DEM permits the particles to be bonded and is used to model the deformation and fracture of solid, while the LBM is used to model fluid flow. These two methods are coupled in a two-way process, i.e., the solid par...

A coupled numerical simulator was developed to model the initiation process of an outburst through coupling two well-established codes. In the simulator, the deformation and failure of coal are modeled with FLAC3D by the geotechnical analysis of coal and rock, the gas desorption and flow are modeled with COMET3 by analyzing coalgas characteristics...

Realizing the potential of geothermal energy as a cheap, green, sustainable resource to provide for the planet’s future energy demands that a key geophysical problem be solved first: how to develop and maintain a network of multiple fluid flow pathways for the time required to deplete the heat within a given region. We present the key components fo...

Gas content in a coal seam is used in mine safety such as gas emission estimation and the assessment of the risk of outbursts of coal and gas in underground coal mines. A direct measurement system has been developed to estimate the gas content. The main components of the system include an innovative sampling-while-drilling unit for coal sampling, a...

An outburst of coal and gas is a major hazard in underground coal mining. It occurs when certain conditions of coal stress, strength and gassiness are met. Based mainly on field observations related to the conditions, a number of indices are used in prediction of the outburst. Some of the indices are considered to be inadequate, inappropriate or im...

An outburst of coal and gas is a major hazard in underground coal mining. It occurs when certain conditions of coal stress, strength and gassiness are met. The outburst is recognized as a two-step process, i.e. initiation and development. Each step has its own characteristics and requires different approaches in numerical modeling. As a first step,...

An outburst of coal and gas in underground coal mines may occur when stress condition and coal failure combine with rapid gas desorption. A mechanical and fluid coupled numerical simulator, SimBurst, has been developed to simulate the initiation process of the outburst, as a first step to model the whole process of the outburst. This paper describe...

We present a finite deformation method for 3-D discrete element modeling. In this method particle rotation is explicitly represented
using quaternion and a complete set of interactions is permitted between two bonded particles, i.e., normal and tangent forces,
rolling and torsional torques. Relative rotation between two particles is decomposed into...

We investigate the macroscopic properties of frictionless nonconvex particles using molecular dynamics. The calculations are based on a simple and efficient method to simulate complex-shaped interacting bodies. The particle shape is represented by Minkowski operators. A multicontact time-continuous interaction between bodies is derived using simple...

In this paper we propose a new algorithm to simulate the dynamics of 3-D interacting rigid bodies. Six degrees of freedom are introduced to describe a single 3-D body or particle, and six relative motions and interactions are permitted between bonded bodies. We develop a new decomposition technique for 3-D rotation and pay particular attention to t...

The existence of granular ratcheting as a long‐time behavior in granular materials is still under discussion in the scientific and engineering community. This behavior refers to the constant accumulation of permanent deformation per cycle, when the granular sample is subjected to loading‐unloading stress cycles with amplitudes well bellow the yield...

ESyS_Particle, the 3-D Discrete Element Model, is used to model the fracture process and the size distribution of rock fragmentation under two different loading conditions: 1) Slow uni-axial compression of a ball aggregate which consists of small bonded particles; 2) Impact of a ball consisting of bonded particles to a stiff wall. We reproduce the...

We simulate rock fracture using ESyS_Particle, which is a 3-D Discrete Element Model developed for modeling geological materials. Two types of simulations are carried out: Unconfined Compressive Test (UCT) and Brazilian Tensile Test (BTT). The results are compared to laboratory tests. Model parameters are determined on the basis of theoretical stud...

One of the most challenging problems in the realistic modeling of
granular materials is how to capture the real shape of the particles.
Here we present a method to simulate systems with complex-shaped
particles. This method integrates developments in two traditionally
separate research areas: computational geometry and molecular dynamics.
The compu...

In this paper, the Discrete Element Model (DEM) is reviewed, and the ESyS_Particle, our new version of DEM, is introduced. We particularly highlight some of the major physical concerns about DEMs and major differences between our model and most current DEMs. In the new model, single particle rotation is introduced and represented by a unit quaterni...

We present a simple and efficient method to simulate three-dimensional, complex-shaped, interacting bodies. The particle shape is represented by Minkowski operators. A time-continuous interaction between these bodies is derived using simple concepts of computational geometry. The model (particles + interactions) is efficient, accurate and easy to i...

In this paper we study analytically the elastic properties of the 2-D and 3-D regular lattices consisting of bonded particles. The particle-scale stiffnesses are derived from the given macroscopic elastic constants (i.e. Young's modulus and Poisson's ratio). Firstly a bonded lattice model is presented. This model permits six kinds of relative motio...

ESyS_Particle, the 3-D Discrete Element Model, is used to model the fracture process and the size distribution of rock fragmentation under two different loading conditions: 1) Slow uni-axial compression of a ball aggregate which consists of small bonded particles; 2) Impact of a ball consisting of bonded particles to a stiff wall. We reproduce the...

In this study, we investigate what basic mechanisms a Discrete Element Model should have in order to reproduce the realistic
wing crack extension, a widely observed phenomenon in uni-axial compression of brittle material with pre-existed crack. Using
our Discrete Element Model—the Lattice Solid Model, we study how cracks propagate when different fo...

One of the most difficult aspect of the realistic modeling of granular materials is how to capture the real shape of the particles.
Here we present a method to simulate two-dimensional granular materials with complex-shaped particles. The particle shape
is represented by the classical concept of a Minkowski sum, which permits the representation of...

The Load Unload Response Ratio (LURR) method is an intermediate-term earthquake prediction approach that has shown considerable
promise. It is inspiring that its predictions using LURR have been improving. Since 2004 we have made a major breakthrough
in intermediate-term earthquake forecasting of the strong earthquakes on the Chinese mainland using...

A series of acoustic emission (AE) experiments of rock failure have been conducted under cyclic load in tri-axial stress tests.
To simulate the hypocenter condition the specimens are loaded by the combined action of a constant stress, intended to simulate
the tectonic loading, and a small sinusoidal disturbance stress, analogous to the Earth tide i...

Seismogenic process is a nonlinear and irreversible one, so that the response to loading of a seismogenic zone is different
from the unloading one. This difference reflects quantitatively the process of an earthquake preparation. A physics-based
new parameter-Load/Unload Response Ratio (LURR) was proposed to measure quantitatively the proximity to...

In this study, 3-D Lattice Solid Model (LSMearth or LSM) was extended by introducing particle-scale rotation. In the new model,
for each 3-D particle, we introduce six degrees of freedom: Three for translational motion, and three for orientation. Six
kinds of relative motions are permitted between two neighboring particles, and six interactions are...

Based on the three-dimensional elastic inclusion model proposed by Dobrovolskii, we developed a rheological inclusion model to study earthquake preparation processes. By using the Corresponding Principle in the theory of rheologic mechanics, we derived the analytic expressions of viscoelastic displacement U(r, t) , V(r, t) and W(r, t), normal strai...

A particle based model, the Lattice Solid Model (LSMearth), has been expanded to include full rigidity between particles and full degrees of freedom for particles including single particle rotation. However, the questions arise: is it necessary to include all of these mechanisms? What happens if we ignore some mechanisms? In this study, we try to a...

High LURR values and observations of Accelerating Moment/Energy Release (AMR/AER) prior to large earthquakes have suggested that intermediate-term earthquake prediction is possible. The LURR and AMR/AER have a similar physical origin. Experiments are very important in exploring the deformation and fracture of earth rock. Acoustic emission experimen...

To further investigate the mechanism of acoustic emission (AE) in the rock fracture experiment, moment tensor analysis was carried out. The AE sources characterized by crack sizes, orientations and fracture modes, are represented by a time-dependent moment tensor. Since the waveforms recorded by AE monitors correlate to the moment tensors, we prefe...

— The Accelerating Moment Release (AMR) preceding earthquakes with magnitude above 5 in Australia that occurred during the last 20 years was analyzed to test the Critical Point Hypothesis. Twelve earthquakes in the catalog were chosen based on a criterion for the number of nearby events. Results show that seven sequences with numerous events record...

The Lattice Solid Model (LSMearth) is a particle based model similar to the Discrete Element Model (DEM). The current LSMerath includes only radial interaction between two linked particles, involving only translational motions of particles. In this study, we extend the LSM by introducing full rigidity interactions between particles and full degrees...

— Statistical tests of Load-Unload Response Ratio (LURR) signals are carried in order to verify statistical robustness of the previous studies using the Lattice Solid Model (Mora et al., 2002b). In each case 24 groups of samples with the same macroscopic parameters (tidal perturbation amplitude A, period T and tectonic loading rate k) but different...

Numerical simulation models provide a means to probe the physics and
dynamics of fault systems. Results from three different simulation
models are presented: the particle based or micro-scale Lattice Solid
Model (Mora and Place, 2002), cellular automaton models (e.g. Weatherley
et al, 2002), and parallel fault continuum models (Mora and Weatherley,...

Statistical tests of Load-Unload Response Ratio signals are carried using the Lattice Solid Model. In each test, 24 samples with the same macroscopic parameters (tidal perturbation amplitude A, period T and tectonic loading rate k) but different random arrangements of particles are studied. A sinusoidal stress perturbation is added to the constant...

The Load-Unload Response Ratio (LURR) method is an intermediate-term earthquake prediction approach that has shown considerable promise. It involves calculating the ratio of a specified energy release measure during loading and unloading where loading and unloading periods are determined from the earth tide induced perturbations in the Coulomb Fail...

The main idea of the Load-Unload Response Ratio (LURR) is that when a system is stable, its response to loading corresponds to its response to unloading, whereas when the system is approaching an unstable state, the response to loading and unloading becomes quite different. High LURR values and observations of Accelerating Moment/Energy Release (AM...

The seismogenic process is nonlinear and irreversible so that the response to loading is different from unloading. This difference reflects the damage of a loaded material. Based on this insight, a new parameter-load/unload response ratio (LURR) was proposed to measure quantitatively the proximity to rock failure and earthquake more than ten years...

On the basis of the lattice model of MORA and PLACE, Discrete Element Method, and Molecular Dynamics approach, another kind of numerical model is developed. The model consists of a 2-D set of particles linked by three kinds of interactions and arranged into triangular lattice. After the fracture criterion and rules of changes between linking states...

In this paper, the tempo-spatial evolution characteristics of the load/unload response ratio (namely) LURR or Y value) before strong earthquakes with magnitude over 6 during 1976–1994 in California of America are studied in detail. The
results show that there appear some high-Y regions cohering with the regional tectonic trend in a great area 3–4 y...