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Articles 1 - 8 of 8
Full-Text Articles in Social and Behavioral Sciences
Implications Of Ballast Degradation Under Cyclic Loading, Sanjay Nimbalkar, Buddhima Indraratna
Implications Of Ballast Degradation Under Cyclic Loading, Sanjay Nimbalkar, Buddhima Indraratna
Faculty of Engineering and Information Sciences - Papers: Part A
In spite of recent advances in track geotechnology, the understanding of the mechanisms of ballast degradation is vital for improved design to withstand high speed cyclic loading. The research conducted at Centre for Geomechanics and Railway Engineering (CGRE) at University of Wollongong (UOW) has shown that ballast degradation is influenced by various factors including the amplitude, frequency, number of load cycles, particle size distribution, confining pressure, angularity and fracture strength of individual grains. A series of cyclic drained triaxial tests were conducted using a largescale cylindrical apparatus designed and built at UOW for frequencies ranging from 10-40 Hz. A low …
Effect Of Temperature On Microstructure And Deformation Mechanism Of Fe-30mn-3si-4al Twip Steel At Strain Rate Of 700 S-1, Zhiping Xiong, Xue-Ping Ren, Jian Shu, Zhe-Lei Wang, Wei-Ping Bao, Shu-Xia Li
Effect Of Temperature On Microstructure And Deformation Mechanism Of Fe-30mn-3si-4al Twip Steel At Strain Rate Of 700 S-1, Zhiping Xiong, Xue-Ping Ren, Jian Shu, Zhe-Lei Wang, Wei-Ping Bao, Shu-Xia Li
Faculty of Engineering and Information Sciences - Papers: Part A
As twinning-induced plasticity (TWIP) steel is one potential material for shaped charge liner due to the combination of high strength and high plasticity, deformation mechanism at high strain rate and high temperature is required to study. Compression experiments of Fe-30Mn-3Si-4Al TWIP steel were conducted using a Gleeble-1500 thermal simulation machine and a split-Hopkinson pressure bar (SHPB) between 298 and 1073 K at strain rates of 10-3 and 700 s-1, respectively. Microstructures were observed using optical microscopy (OM) and transmission electron microscopy (TEM). Results show that flow stress and densities of deformation twins and dislocations decrease with increasing deformation temperature at …
Interface Analysis And Hot Deformation Behaviour Of A Novel Laminated Composite With High-Cr Cast Iron And Low Carbon Steel Prepared By Hot Compression Bonding, Zhengyi Jiang, Xingjian Gao, Sheng-Li Li, Hong Mei Zhang, Dengfu Chen, Jian Zhong Xu
Interface Analysis And Hot Deformation Behaviour Of A Novel Laminated Composite With High-Cr Cast Iron And Low Carbon Steel Prepared By Hot Compression Bonding, Zhengyi Jiang, Xingjian Gao, Sheng-Li Li, Hong Mei Zhang, Dengfu Chen, Jian Zhong Xu
Faculty of Engineering and Information Sciences - Papers: Part A
A hot compression bonding process was developed to prepare a novel laminated composite consisting of high-Cr cast iron (HCCI) as the inner layer and low carbon steel (LCS) as the outer layers on a Gleeble 3500 thermomechanical simulator at a temperature of 950 °C and a strain rate of 0.001 S-1. Interfacial bond quality and hot deformation behaviour of the laminate were studied by microstructural characterisation and mechanical tests. Experimental results show that the metallurgical bond between the constituent metals was achieved under the proposed bonding conditions without discernible defects and the formation of interlayer or intermetallic layer …
Coupled Discrete Element-Finite Difference Method For Analysing The Load-Deformation Behaviour Of A Single Stone Column In Soft Soil, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn, Scott W. Sloan
Coupled Discrete Element-Finite Difference Method For Analysing The Load-Deformation Behaviour Of A Single Stone Column In Soft Soil, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn, Scott W. Sloan
Faculty of Engineering and Information Sciences - Papers: Part A
Experimental studies and numerical modelling of the deformation of soft clay stabilised by stone columns have been conducted over the past few decades. Continuum-based numerical models have provided valuable insight into the prediction of settlement, lateral deformation, and stress and strain-rate dependent behaviour of stone columns at a macroscopic scale, but because they consist of granular material such as crushed rock, gravel, and waste rock aggregates, their behaviour is influenced by inter-particle micromechanics and cannot be modelled properly using these models. In this paper a novel coupled model of the discrete element method (DEM) and finite difference method (FDM) is …
Oxide Scale Characterization Of Ferritic Stainless Steel And Its Deformation And Friction In Hot Rolling, Xiawei Cheng, Zhengyi Jiang, Dongbin Wei, Liang Hao, Jingwei Zhao, Laizhu Jiang
Oxide Scale Characterization Of Ferritic Stainless Steel And Its Deformation And Friction In Hot Rolling, Xiawei Cheng, Zhengyi Jiang, Dongbin Wei, Liang Hao, Jingwei Zhao, Laizhu Jiang
Faculty of Engineering and Information Sciences - Papers: Part A
The oxidation kinetics of ferritic stainless steel 430 was studied in dry and humid air at 1090 °C by Thermo Gravimetric Analysis (TGA). Different atmospheres and heating times were adopted for reheating to obtain different compositions and thickness of the oxide scale. Hot rolling was performed on a 2-high Hille 100 experimental rolling mill at various reductions. Oxide scale thickness and composition were analysed with optical microscopy (OM), scanning electron microscope (SEM) and X-ray diffraction (XRD). The surface profiles were examined by a digital microscope, and the topographic features of the thin oxide scale surface were examined with an atomic …
Thermal Stability And Properties Of Deformation-Processed Cu-Fe In Situ Composites, Keming Liu, Zhengyi Jiang, Jingwei Zhao, Jin Zou, Lei Lu, Deping Lu
Thermal Stability And Properties Of Deformation-Processed Cu-Fe In Situ Composites, Keming Liu, Zhengyi Jiang, Jingwei Zhao, Jin Zou, Lei Lu, Deping Lu
Faculty of Engineering and Information Sciences - Papers: Part A
This paper investigated the thermal stability, tensile strength, and conductivity of deformation-processed Cu-14Fe in situ composites produced by thermo-mechanical processing. The thermal stability was analyzed using scanning electronic microscope and transmission electron microscope. The tensile strength and conductivity were evaluated using tensile-testing machine and micro-ohmmeter, respectively. The Fe fibers in the deformation-processed Cu-14Fe in situ composites undergo edge recession, longitudinal splitting, cylinderization, break-up, and spheroidization during the heat treatment. The Cu matrix experiences recovery, recrystallization, and precipitation phase transition. The tensile strength and conductivity first increase with increasing temperature of heat treatment, reach peak values at different temperatures, and then …
Effect Of Extreme Pressure Additives On The Deformation Behavior Of Oxide Scale During The Hot Rolling Of Ferritic Stainless Steel Strips, Liang Hao, Zhengyi Jiang, Xiawei Cheng, Jingwei Zhao, Dongbin Wei, Laizhu Jiang, Suzhen Luo, Ming Luo, Li Ma
Effect Of Extreme Pressure Additives On The Deformation Behavior Of Oxide Scale During The Hot Rolling Of Ferritic Stainless Steel Strips, Liang Hao, Zhengyi Jiang, Xiawei Cheng, Jingwei Zhao, Dongbin Wei, Laizhu Jiang, Suzhen Luo, Ming Luo, Li Ma
Faculty of Engineering and Information Sciences - Papers: Part A
High-speed steel (HSS) materials are universally used as work rolls for the hot rolling of stainless steels. Their use has increased the output of the rolling mill and decreased roll material consumption and grinding. Sticking defects often occur, however, during the hot rolling process. In this article, extreme pressure (EP) additives were dropped on the HSS samples at high temperature. Zinc dialkyl dithiophosphate (ZDDP) was chosen as the most effective EP additive by scratch tests on the HSS samples. In order to determine the optimum proportion of ZDDP in the lubricant, two reduction rates were tested on a Hille 100 …
Recent Advances In Railroad Infrastructure And Track Performance - Australian Experience, Buddhima Indraratna, Sanjay Nimbalkar
Recent Advances In Railroad Infrastructure And Track Performance - Australian Experience, Buddhima Indraratna, Sanjay Nimbalkar
Faculty of Engineering and Information Sciences - Papers: Part A
As trains become longer, heavier and quicker, ballast shows signs of distress and degradation, leading to deterioration of the track geometry. Appropriate stabilisation techniques using artificial inclusions such as polymeric geosynthetics and energy-absorbing shock mats are needed to improve track stability and longevity. Large-scale laboratory tests at University of Wollongong revealed that the geogrids with an optimum aperture governed the effectiveness of the reinforcement mechanism. The use of shock mats was influenced by their placement position and the type of subgrade (e.g. estuarine soil, rock etc.). In these studies, different types of geosynthetics and shock mats were placed beneath the …