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Faculty of Engineering and Information Sciences - Papers: Part A

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Full-Text Articles in Social and Behavioral Sciences

Application Of Fractional Calculus In Modelling Ballast Deformation Under Cyclic Loading, Yifei Sun, Buddhima Indraratna, John Philip Carter, Timothy R. Marchant, Sanjay Nimbalkar Jan 2017

Application Of Fractional Calculus In Modelling Ballast Deformation Under Cyclic Loading, Yifei Sun, Buddhima Indraratna, John Philip Carter, Timothy R. Marchant, Sanjay Nimbalkar

Faculty of Engineering and Information Sciences - Papers: Part A

Most constitutive models can only simulate cumulative deformation after a limited number of cycles. However, railroad ballast usually experiences a large number of train passages that cause history-dependent long-term deformation. Fractional calculus is an efficient tool for modelling this phenomenon and therefore is incorporated into a constitutive model for predicting the cumulative deformation. The proposed model is further validated by comparing the model predictions with a series of corresponding experimental results. It is observed that the proposed model can realistically simulate the cumulative deformation of ballast from the onset of loading up to a large number of load cycles.


Development Of A Novel Multi-Layer Mre Isolator For Suppression Of Building Vibrations Under Seismic Events, Jian Yang, Shuaishuai Sun, Tongfei Tian, Weihua Li, Haiping Du, Gursel Alici, Masami Nakano Jan 2016

Development Of A Novel Multi-Layer Mre Isolator For Suppression Of Building Vibrations Under Seismic Events, Jian Yang, Shuaishuai Sun, Tongfei Tian, Weihua Li, Haiping Du, Gursel Alici, Masami Nakano

Faculty of Engineering and Information Sciences - Papers: Part A

Protecting civil engineering structures from uncontrollable events such as earthquakes while maintaining their structural integrity and serviceability is very important; this paper describes the performance of a stiffness softening magnetorheological elastomer (MRE) isolator in a scaled three storey building. In order to construct a closed-loop system, a scaled three storey building was designed and built according to the scaling laws, and then four MRE isolator prototypes were fabricated and utilised to isolate the building from the motion induced by a scaled El Centro earthquake. Fuzzy logic was used to output the current signals to the isolators, based on the real-time ...


Experimental Investigation Of Gfrp-Reinforced And Gfrp-Encased Square Concrete Specimens Under Axial And Eccentric Load, And Four-Point Bending Test, Muhammad N. S Hadi, Jim Youssef Jan 2016

Experimental Investigation Of Gfrp-Reinforced And Gfrp-Encased Square Concrete Specimens Under Axial And Eccentric Load, And Four-Point Bending Test, Muhammad N. S Hadi, Jim Youssef

Faculty of Engineering and Information Sciences - Papers: Part A

This paper presents the results of an experimental study on the axial and flexural behavior of square concrete members reinforced with glass fiber-reinforced polymer (GFRP) bars and embedded with pultruded GFRP structural sections under different loading conditions. The main parameters investigated in this study were the influence of the type of internal reinforcement (steel bars, GFRP bars and pultruded GFRP structural I-sections and C-sections) and magnitude of load eccentricity on the flexural and compressive behavior of square concrete members. To fulfil the objectives of this study, 16 reinforced concrete specimens were tested, of which 12 were tested as columns under ...


Simultaneous Grain Growth And Grain Refinement In Bulk Ultrafine-Grained Copper Under Tensile Deformation At Room Temperature, Hai Liang Yu, Cheng Lu, Anh Kiet Tieu, Hui Jun Li, Ajit R. Godbole, Charlie Kong, Xing Zhao Jan 2016

Simultaneous Grain Growth And Grain Refinement In Bulk Ultrafine-Grained Copper Under Tensile Deformation At Room Temperature, Hai Liang Yu, Cheng Lu, Anh Kiet Tieu, Hui Jun Li, Ajit R. Godbole, Charlie Kong, Xing Zhao

Faculty of Engineering and Information Sciences - Papers: Part A

Grain growth and grain refinement behavior during deformation determine the strength and ductility of ultrafine-grained materials. We used asymmetric cryorolling to fabricate ultrafine-grained copper sheets with an average grain width of 230 nm and having a laminate structure. The sheets show a high-true failure strain of 1.5. Observation of the microstructure at the fracture surface reveals that ultrafine laminate-structured grains were simultaneously transformed into both equiaxed nanograins and coarse grains under tensile deformation at room temperature.


Stability Control Of Force-Reflected Nonlinear Multilateral Teleoperation System Under Time-Varying Delays, Da Sun, Fazel Naghdy, Haiping Du Jan 2016

Stability Control Of Force-Reflected Nonlinear Multilateral Teleoperation System Under Time-Varying Delays, Da Sun, Fazel Naghdy, Haiping Du

Faculty of Engineering and Information Sciences - Papers: Part A

A novel control algorithm based on the modified wave-variable controllers is proposed to achieve accurate position synchronization and reasonable force tracking of the nonlinear single-master-multiple-slave teleoperation system and simultaneously guarantee overall system's stability in the presence of large time-varying delays. The system stability in different scenarios of human and environment situations has been analyzed. The proposed method is validated through experimental work based on the 3-DOF trilateral teleoperation system consisting of three different manipulators. The experimental results clearly demonstrate the feasibility of the proposed algorithm to achieve high transparency and robust stability in nonlinear single-master-multiple-slave teleoperation system in the ...


Outlier Robust Small-Area Estimation Under Spatial Correlation, Timo Schmid, Nikos Tzavidis, Ralf Munnich, Raymond L. Chambers Jan 2016

Outlier Robust Small-Area Estimation Under Spatial Correlation, Timo Schmid, Nikos Tzavidis, Ralf Munnich, Raymond L. Chambers

Faculty of Engineering and Information Sciences - Papers: Part A

Modern systems of official statistics require the estimation and publication of business statistics for disaggregated domains, for example, industry domains and geographical regions. Outlier robust methods have proven to be useful for small-area estimation. Recently proposed outlier robust model-based small-area methods assume, however, uncorrelated random effects. Spatial dependencies, resulting from similar industry domains or geographic regions, often occur. In this paper, we propose an outlier robust small-area methodology that allows for the presence of spatial correlation in the data. In particular, we present a robust predictive methodology that incorporates the potential spatial impact from other areas (domains) on the small ...


Design-Oriented Stress–Strain Model For Concrete Under Combined Frp-Steel Confinement, G Lin, Tao Yu, Jin Guang Teng Jan 2016

Design-Oriented Stress–Strain Model For Concrete Under Combined Frp-Steel Confinement, G Lin, Tao Yu, Jin Guang Teng

Faculty of Engineering and Information Sciences - Papers: Part A

Extensive research has been conducted on fiber-reinforced polymer (FRP)-confined plain and RC columns, leading to a large number of stress–strain models. Most of these models have been developed for FRP-confined plain concrete and are thus applicable only to concrete in FRP-confined RC columns with a negligible amount of transverse steel reinforcement. The few models that have been developed for concrete under the combined confinement of FRP and transverse steel reinforcement are either inaccurate or too complex for direct use in design. This paper presents an accurate design-oriented stress–strain model for concrete under combined FRP-steel confinement in FRP-confined ...


Experimental Study On Frp Tube Reinforced Concrete Columns Under Different Loading Conditions, Weiqiang Wang, M Neaz Sheikh, Muhammad N. S Hadi Jan 2016

Experimental Study On Frp Tube Reinforced Concrete Columns Under Different Loading Conditions, Weiqiang Wang, M Neaz Sheikh, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part A

The behavior of fiber-reinforced polymer (FRP) tube reinforced concrete (FTRC) columns under different loading conditions was investigated in this study. Four groups of 16 specimens were cast and tested. Specimens in the first group (the reference group) were re- inforced with longitudinal steel bars and steel helices (Group REF). Specimens in the second group were reinforced with intact glass FRP tubes (Group IT). Specimens in the third group were also reinforced with intact glass FRP tubes. In addition, polymer grid was embedded into the concrete cover to reduce the cover spalling (Group ITG). Specimens in the fourth group were reinforced ...


Experimental Investigation Of The Behaviour Of Concrete Beams Reinforced With Gfrp Bars Under Static And Impact Loading, Matthew Goldston, Alex M. Remennikov, M Neaz Sheikh Jan 2016

Experimental Investigation Of The Behaviour Of Concrete Beams Reinforced With Gfrp Bars Under Static And Impact Loading, Matthew Goldston, Alex M. Remennikov, M Neaz Sheikh

Faculty of Engineering and Information Sciences - Papers: Part A

Composite materials, including Fibre Reinforced Polymer (FRP) bars, have been gaining momentum as alternatives to traditional steel reinforcements in civil and structural engineering sectors. FRP materials are non-corrosive, non-conductive, and lightweight and possess high longitudinal tensile strength, which are advantageous for their use in civil infrastructure. This paper presents the results of an experimental investigation into the effects of the use of glass FRP (GFRP) bars as internal reinforcement on the behaviour of concrete beams. Both static and dynamic (impact) behaviours of the beam have been investigated. Twelve GFRP reinforced concrete (RC) beams were designed, cast and tested. Six GFRP ...


Coke Degradation Under Simulated Blast Furnace Conditions, Xing Xing, Harold P. Rogers, Guangqing Zhang, Kim Hockings, Paul Zulli, Oleg Ostrovski Jan 2016

Coke Degradation Under Simulated Blast Furnace Conditions, Xing Xing, Harold P. Rogers, Guangqing Zhang, Kim Hockings, Paul Zulli, Oleg Ostrovski

Faculty of Engineering and Information Sciences - Papers: Part A

Three metallurgical cokes made from coking coals over a significant range in rank were subjected to treatment with blast furnace-like gas composition-temperature profile to 1 673 K, annealing under N2 to 2 273 K and gasification with subsequent annealing at 1 873 and 2 273 K. The degradation of cokes after reaction and annealing was characterised using I-drum tumbling, tensile testing, ultra-micro indentation and X-ray diffraction. Both gasification and annealing decreased the mechanical strength of coke. Compared with annealing at 1 673 K, gasification at same temperature caused larger degradation for all three cokes, and the effect was more significant ...


Driver Alerting System Using Range Estimation Of Electric Vehicles In Real Time Under Dynamically Varying Environmental Conditions, Vincent R. Tannahill, Kashem M. Muttaqi, Danny Sutanto Jan 2016

Driver Alerting System Using Range Estimation Of Electric Vehicles In Real Time Under Dynamically Varying Environmental Conditions, Vincent R. Tannahill, Kashem M. Muttaqi, Danny Sutanto

Faculty of Engineering and Information Sciences - Papers: Part A

As the technology supporting electric vehicles (EVs) is rapidly progressing and the cost of EV components is reducing, EVs are becoming more feasible for use in Australia and in many countries around the world. However, the public perception of EVs and their perceived limitations result in a slow uptake of the technology, partially because of the uncertainty regarding the ability of an EV to meet the driving needs of the general population. Range anxiety is a particular concern with drivers having fear of being stranded by a depleted EV battery. This study explores means of reducing range anxiety by taking ...


Relations Between Robustness And Rka Security Under Public-Key Encryption, Hui Cui, Yi Mu, Man Ho Au Jan 2016

Relations Between Robustness And Rka Security Under Public-Key Encryption, Hui Cui, Yi Mu, Man Ho Au

Faculty of Engineering and Information Sciences - Papers: Part A

We revisit the notions of robustness introduced by Abdalla, Bellare and Neven (TCC 2010), and related-key attack (RKA) security raised by Bellare, Cash and Miller (ASIACRYPT 2011). In the setting of public-key encryption (PKE), robustness means that it is hard to produce a ciphertext that is valid for two different users, while RKA security means that a PKE scheme is still secure even when an attacker can induce modifications in a decryption key, and subsequently observe the outcome of this PKE scheme under this modified key. In this paper, we explore the relationship between RKA security and various notions of ...


Mechanical Fatigue Performance Of Pcl-Chondroprogenitor Constructs After Cell Culture Under Bioreactor Mechanical Stimulus, J A. Panadero, Vitor Sencadas, Sonia C.M. Silva, Clarisse Ribeiro, Vítor Correia, F M. Gama, J L. Gomez Ribelles, Senentxu Lanceros-Méndez Jan 2016

Mechanical Fatigue Performance Of Pcl-Chondroprogenitor Constructs After Cell Culture Under Bioreactor Mechanical Stimulus, J A. Panadero, Vitor Sencadas, Sonia C.M. Silva, Clarisse Ribeiro, Vítor Correia, F M. Gama, J L. Gomez Ribelles, Senentxu Lanceros-Méndez

Faculty of Engineering and Information Sciences - Papers: Part A

In tissue engineering of cartilage, polymeric scaffolds are implanted in the damaged tissue and subjected to repeated compression loading cycles. The possibility of failure due to mechanical fatigue has not been properly addressed in these scaffolds. Nevertheless, the macroporous scaffold is susceptible to failure after repeated loading- unloading cycles. This is related to inherent discontinuities in the material due to the micropore structure of the macropore walls that act as stress concentration points. In this work, chondrogenic precursor cells have been seeded in poly-e-caprolactone (PCL) scaffolds with fibrin and some were submitted to free swelling culture and others to cyclic ...


Molecular Dynamics Study On The Grain Boundary Dislocation Source In Nanocrystalline Copper Under Tensile Loading, Liang Zhang, Cheng Lu, A Kiet Tieu, Linqing Pei, Xing Zhao, Kuiyu Cheng Jan 2015

Molecular Dynamics Study On The Grain Boundary Dislocation Source In Nanocrystalline Copper Under Tensile Loading, Liang Zhang, Cheng Lu, A Kiet Tieu, Linqing Pei, Xing Zhao, Kuiyu Cheng

Faculty of Engineering and Information Sciences - Papers: Part A

Grain boundary (GB) is the interface between different oriented crystals of the same material, and it can have a significant effect on the many properties of materials. When the average or entire range of grain size is reduced to less than 100 nm, the conventional plastic deformation mechanisms dominated by dislocation processes become difficult and GBmediated deformation mechanisms become increasingly important. One of the mechanisms that can play a profound role in the strength and plasticity of metallic polycrystalline materials is the heterogeneous nucleation and emission of dislocations from GB. In this study, we conducted molecular dynamics simulations to study ...


Molecular Dynamics Simulation On Generalized Stacking Fault Energies Of Fcc Metals Under Preloading Stress, Liang Zhang, Cheng Lu, A Kiet Tieu, Xing Zhao, Linqing Pei, Guillaume Michal Jan 2015

Molecular Dynamics Simulation On Generalized Stacking Fault Energies Of Fcc Metals Under Preloading Stress, Liang Zhang, Cheng Lu, A Kiet Tieu, Xing Zhao, Linqing Pei, Guillaume Michal

Faculty of Engineering and Information Sciences - Papers: Part A

Molecular dynamics (MD) simulations are performed to investigate the effects of stress on generalized stacking fault (GSF) energy of three fcc metals (Cu, Al, and Ni). The simulation model is deformed by uniaxial tension or compression in each of [111], [11-2], and [1-10] directions, respectively, before shifting the lattice to calculate the GSF curve. Simulation results show that the values of unstable stacking fault energy (γusf), stable stacking fault energy (γsf), and unstable twin fault energy (γutf) of the three elements can change with the preloaded tensile or compressive stress in different directions. The ratio of γsf/γusf, which is ...


Alleviation Of Neutral-To-Ground Potential Rise Under Unbalanced Allocation Of Rooftop Pv Using Distributed Energy Storage, Md Jan E Alam, Kashem M. Muttaqi, Danny Sutanto Jan 2015

Alleviation Of Neutral-To-Ground Potential Rise Under Unbalanced Allocation Of Rooftop Pv Using Distributed Energy Storage, Md Jan E Alam, Kashem M. Muttaqi, Danny Sutanto

Faculty of Engineering and Information Sciences - Papers: Part A

A high penetration of one-phase rooftop solar photovoltaic (PV) units with unbalanced allocation can create considerable neutral current and neutral potential rise in low voltage (LV) four-wire multigrounded distribution networks, even with balanced loads. Because of the limitations of traditional strategies to mitigate the combined effect of load and PV unbalance, this paper proposes the use of distributed energy storage to reduce the neutral current and neutral potential under a high penetration of unbalanced rooftop solar PV allocation. A power-balancing algorithm based on charge/discharge control is developed to continuously adjust the power exchange with the grid to mitigate the ...


Dean-Flow-Coupled Elasto-Inertial Three-Dimensional Particle Focusing Under Viscoelastic Flow In A Straight Channel With Asymmetrical Expansion-Contraction Cavity Arrays, Dan Yuan, Jie Zhang, Sheng Yan, Chao Pan, Gursel Alici, Nam-Trung Nguyen, Weihua Li Jan 2015

Dean-Flow-Coupled Elasto-Inertial Three-Dimensional Particle Focusing Under Viscoelastic Flow In A Straight Channel With Asymmetrical Expansion-Contraction Cavity Arrays, Dan Yuan, Jie Zhang, Sheng Yan, Chao Pan, Gursel Alici, Nam-Trung Nguyen, Weihua Li

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, 3D particle focusing in a straight channel with asymmetrical expansion-contraction cavity arrays (ECCA channel) is achieved by exploiting the dean-flow-coupled elasto-inertial effects. First, the mechanism of particle focusing in both Newtonian and non-Newtonian fluids was introduced. Then particle focusing was demonstrated experimentally in this channel with Newtonian and non- Newtonian fluids using three different sized particles (3.2 lm, 4.8 lm, and 13 lm), respectively. Also, the effects of dean flow (or secondary flow) induced by expansion- contraction cavity arrays were highlighted by comparing the particle distributions in a single straight rectangular channel with that in ...


Macrostrength And Pore Structure Of Coke Subjected To Gasification And Annealing Under Blast Furnace Conditions, Xing Xing, Harold P. Rogers, Guangqing Zhang, Paul Zulli, Oleg Ostrovski Jan 2015

Macrostrength And Pore Structure Of Coke Subjected To Gasification And Annealing Under Blast Furnace Conditions, Xing Xing, Harold P. Rogers, Guangqing Zhang, Paul Zulli, Oleg Ostrovski

Faculty of Engineering and Information Sciences - Papers: Part A

Metallurgical cokes were subjected to gasification by CO-CO2-N2 gas with blast furnace-like composition-temperature profile to 1400 °C and annealing under N2 at temperature up to 2000 °C. The degradation of coke strength following reaction and annealing was characterised using tensile testing. Both gasification and annealing decreased the mechanical strength of coke. Degradation of all examined cokes by gasification at 1400 °C was stronger in comparison with annealing at the same temperature.


Uncertainty Management In Multiobjective Hydro-Thermal Self-Scheduling Under Emission Considerations, Jamshid Aghaei, Abdollah Ahmadi, Abdorreza Rabiee, Vassilios G. Agelidis, Kashem M. Muttaqi, H A. Shayanfar Jan 2015

Uncertainty Management In Multiobjective Hydro-Thermal Self-Scheduling Under Emission Considerations, Jamshid Aghaei, Abdollah Ahmadi, Abdorreza Rabiee, Vassilios G. Agelidis, Kashem M. Muttaqi, H A. Shayanfar

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, a stochastic multiobjective framework is proposed for a day-ahead short-term Hydro Thermal Self-Scheduling (HTSS) problem for joint energy and reserve markets. An efficient linear formulations are introduced in this paper to deal with the nonlinearity of original problem due to the dynamic ramp rate limits, prohibited operating zones, operating services of thermal plants, multi-head power discharge characteristics of hydro generating units and spillage of reservoirs. Besides, system uncertainties including the generating units' contingencies and price uncertainty are explicitly considered in the stochastic market clearing scheme. For the stochastic modeling of probable multiobjective optimization scenarios, a lattice Monte ...


In-Arrears Interest Rate Derivatives Under The 3/2 Model, Joanna M. Goard Jan 2015

In-Arrears Interest Rate Derivatives Under The 3/2 Model, Joanna M. Goard

Faculty of Engineering and Information Sciences - Papers: Part A

Lie symmetry methods are used to find a closed form solution for in-arrears swaps under the 3/2 model ( ( ) ) ˆ 3 dr = r A t −α r dt + cr 2dZ . As well, approximate solutions are found for short-tenor inarrears caplets and floorlets under the same interest rate model. Comparisons are made of the approximate option values with those obtained with a computationally-intensive numerical scheme. The approximate pricing is found to be substantially fast easy to implement, while the relative errors with respect to the “true” prices are very small.


Variational Inequality Model For Cordon-Based Congestion Pricing Under Side Constrained Stochastic User Equilibrium Conditions, Zhiyuan Liu, Qiang Meng, Shuaian Wang Jan 2014

Variational Inequality Model For Cordon-Based Congestion Pricing Under Side Constrained Stochastic User Equilibrium Conditions, Zhiyuan Liu, Qiang Meng, Shuaian Wang

Faculty of Engineering and Information Sciences - Papers: Part A

A major objective of the practical implemented cordon-based congestion pricing schemes is to maintain the traffic conditions within the cordon area, which is rarely considered in most of the existing studies. Thus, this paper addresses the optimal toll charge pattern that can restrict the total inbound flow of each cordon to a predetermined threshold. The toll charges on all the entry links of one cordon are required to be identical, for the ease of implementation and users' recognition. The users' route choice behaviour is assumed to follow stochastic user equilibrium (SUE) with asymmetric link travel time functions. It is shown ...


The Pricing Of Credit Default Swaps Under A Generalized Mixed Fractional Brownian Motion, Xinjiang He, Wenting Chen Jan 2014

The Pricing Of Credit Default Swaps Under A Generalized Mixed Fractional Brownian Motion, Xinjiang He, Wenting Chen

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, we consider the pricing of the CDS (credit default swap) under a GMFBM (generalized mixed fractional Brownian motion) model. As the name suggests, the GMFBM model is indeed a generalization of all the FBM (fractional Brownian motion) models used in the literature, and is proved to be able to effectively capture the long-range dependence of the stock returns. To develop the pricing mechanics of the CDS, we firstly derive a sufficient condition for the market modeled under the GMFBM to be arbitrage free. Then under the risk-neutral assumption, the CDS is fairly priced by investigating the two ...


Global Optimization Method For Robust Pricing Of Transportation Networks Under Uncertain Demand, Shuaian Wang, Lauren Gardner, S.Travis Waller Jan 2014

Global Optimization Method For Robust Pricing Of Transportation Networks Under Uncertain Demand, Shuaian Wang, Lauren Gardner, S.Travis Waller

Faculty of Engineering and Information Sciences - Papers: Part A

We extend the existing toll pricing studies with fixed demand to stochastic demand. A new and practical second-best pricing problem with uncertain demand is proposed and formulated as a stochastic mathematical program with equilibrium constraints. In view of the problem structure, we develop a tailored global optimization algorithm. This algorithm incorporates a sample average approximation scheme, a relaxation-strengthening method, and a linearization approach. The proposed global optimization algorithm is applied to three networks: a two-link network, a seven-eleven network and the Sioux-Falls network. The results demonstrate that using a single fixed estimation of future demand may overestimate the future system ...


Numerical Analysis Of High-Strength Concrete-Filled Steel Tubular Slender Beam-Columns Under Cyclic Loading, Vipulkumar Patel, Qing Quan Liang, Muhammad N. S Hadi Jan 2014

Numerical Analysis Of High-Strength Concrete-Filled Steel Tubular Slender Beam-Columns Under Cyclic Loading, Vipulkumar Patel, Qing Quan Liang, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part A

The effects of cyclic local buckling on the behavior of concrete-filled steel tubular (CFST) slender beam-columns under cyclic loading were approximately considered in existing analytical methods by modifying the stress– strain curve for the steel tube in compression. These methods, however, cannot simulate the progressive cyclic local buckling of the steel tubes. This paper presents a new efficient numerical model for predicting the cyclic performance of high strength rectangular CFST slender beam-columns accounting for the effects of progressive cyclic local buckling of steel tube walls under stress gradients. Uniaxial cyclic constitutive laws for the concrete core and steel tubes are ...


Molecular Dynamics Simulation On Σ5 Grain Boundaries Of Copper Bicrystal Under Tensile And Shear Deformation, Liang Zhang, Cheng Lu, A Kiet Tieu Jan 2014

Molecular Dynamics Simulation On Σ5 Grain Boundaries Of Copper Bicrystal Under Tensile And Shear Deformation, Liang Zhang, Cheng Lu, A Kiet Tieu

Faculty of Engineering and Information Sciences - Papers: Part A

Molecular Dynamics simulation are employed to investigate the structures and mechanical behavior of both symmetric and asymmetric Σ5[0 0 1] tilt grain boundaries (GBs) of copper bicrystal under uniaxial tension and shear deformation. Simulation results indicate that the Σ5 asymmetric GBs can facet into their corresponding symmetric GB structures. The maximum tensile stress of symmetric GBs is higher than the asymmetric ones at both 10 K and 300 K, which suggests the symmetric GBs may have a more stable boundary structures. All the Σ5 GBs investigate in this study can migrate under the shear deformation with different velocity. The ...


Analysis Of Internal Crack Healing Mechanism Under Rolling Deformation, Haitao Gao, Zhengrong Ai, Hailiang Yu, Hongyan Wu, Xianghua Liu Jan 2014

Analysis Of Internal Crack Healing Mechanism Under Rolling Deformation, Haitao Gao, Zhengrong Ai, Hailiang Yu, Hongyan Wu, Xianghua Liu

Faculty of Engineering and Information Sciences - Papers: Part A

A new experimental method, called the 'hole filling method', is proposed to simulate the healing of internal cracks in rolled workpieces. Based on the experimental results, the evolution in the microstructure, in terms of diffusion, nucleation and recrystallisation were used to analyze the crack healing mechanism. We also validated the phenomenon of segmented healing. Internal crack healing involves plastic deformation, heat transfer and an increase in the free energy introduced by the cracks. It is proposed that internal cracks heal better under high plastic deformation followed by slow cooling after rolling. Crack healing is controlled by diffusion of atoms from ...


Closure To "Deformation Of Coal Fouled Ballast Stabilized With Geogrid Under Cyclic Load" By Buddhima Indraratna, Ngoc Trung Ngo, And Cholachat Rujikiatkamjorn, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn Jan 2014

Closure To "Deformation Of Coal Fouled Ballast Stabilized With Geogrid Under Cyclic Load" By Buddhima Indraratna, Ngoc Trung Ngo, And Cholachat Rujikiatkamjorn, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn

Faculty of Engineering and Information Sciences - Papers: Part A

The writers highly appreciate the keen feedback provided by the discusser and also for raising some other important aspects of the experimental program. While the writers are in general agreement with the discusser’s comments, some points warrant further clarification.


Behaviour Of Clay-Fouled Ballast Under Cyclic Loading, Nayoma Tennakoon, Buddhima Indraratna Jan 2014

Behaviour Of Clay-Fouled Ballast Under Cyclic Loading, Nayoma Tennakoon, Buddhima Indraratna

Faculty of Engineering and Information Sciences - Papers: Part A

Expansion of the rail network in congested coastal Australia compels track construction on soft clayey subgrade, including fine-grained estuarine soils. In such low-lying areas, where the water table is close to the ground surface, the saturated soft subgrade is often subjected to pumping (mud slurry) under the application of cyclic wheel loads, thereby causing fouling of the overlying ballast. This technical note presents the results of a series of large-scale, drained, cyclic, triaxial tests conducted on clay-fouled ballast. The impact of fouling on the stress-strain behaviour, resilient modulus and degradation of ballast is discussed.


Resonant Electronic Transport Through A Triple Quantum-Dot With K-Type Level Structure Under Dual Radiation Fields, Chun Guan, Yunhui Xing, Chao Zhang, Zhongshui Ma Jan 2014

Resonant Electronic Transport Through A Triple Quantum-Dot With K-Type Level Structure Under Dual Radiation Fields, Chun Guan, Yunhui Xing, Chao Zhang, Zhongshui Ma

Faculty of Engineering and Information Sciences - Papers: Part A

Due to quantum interference, light can transmit through dense atomic media, a phenomenon known as electromagnetically induced transparency (EIT). We propose that EIT is not limited to light transmission and there is an electronic analog where resonant transparency in charge transport in an opaque structure can be induced by electromagnetic radiation. A triple-quantum-dots system with K-type level structure is generally opaque due to the level in the center dot being significantly higher and therefore hopping from the left dot to the center dot is almost forbidden. We demonstrate that an electromagnetically induced electron transparency (EIET) in charge of transport can ...


Behaviour Of Gfrp Tube Reinforced Concrete Columns Under Axial Compression, Weiqiang Wang, M Neaz Sheikh, Muhammad N. S Hadi, Blake Lyons Jan 2014

Behaviour Of Gfrp Tube Reinforced Concrete Columns Under Axial Compression, Weiqiang Wang, M Neaz Sheikh, Muhammad N. S Hadi, Blake Lyons

Faculty of Engineering and Information Sciences - Papers: Part A

This paper reports the result of an experimental investigation on the behaviour of Glass Fibre Reinforced Polymer (GFRP) tube reinforced concrete columns under axial compression. The GFRP tube was placed into the concrete to provide reinforcement both in the longitudinal and transverse directions. In this study, a total of 8 columns with 150 mm diameter and 300 mm height were cast and tested under axial compression. The columns were divided into four groups and each group contains two identical columns. The first group had two columns of plain concrete, and the remaining three groups were reinforced with solid, axially perforated ...