Djajakesukma, SL, Samali, B, Li, J & Nguyen, H 2002, 'MODELLING AND IDENTIFICATION OF MR DAMPER FOR SEMIACTIVE STIFFNESS DAMPER', The Proceedings of the International Conference on Motion and Vibration Control, vol. 6.2, no. 0, pp. 1197-1202.
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Indraratna, B & Radampola, S 2002, 'Analysis of Critical Hydraulic Gradient for Particle Movement in Filtration', Journal of Geotechnical and Geoenvironmental Engineering, vol. 128, no. 4, pp. 347-350.
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Indraratna, B & Salim, W 2002, 'Modelling of particle breakage of coarse aggregates incorporating strength and dilatancy', Proceedings of the Institution of Civil Engineers - Geotechnical Engineering, vol. 155, no. 4, pp. 243-252.
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The degradation of coarse aggregates under shear stresses and its influence on the shear strength is studied, considering the energy consumption by particle breakage during shearing. An analytical model is developed relating the deviator stress ratio, dilatancy, friction angle and particle breakage under triaxial loading. Large-scale triaxial testing of latite basalt has been conducted, and the extent of particle breakage during shearing has been quantified. The breakage of particles under monotonic triaxial loading has been considered within the scope of this paper, and the modelling of particle breakage of aggregates under cyclic loading will be presented in a follow-up paper. The results show that the breakage of particles continues to increase beyond the peak deviator stress. The energy consumption by particle breakage is non-linearly related to the particle breakage index. The model also evaluates the effect of particle breakage on the friction angle of ballast. This study sheds further light on the basic angle of friction, which is independent of the breakage of particles during shearing.
Indraratna, B, Glamore, WC & Tularam, GA 2002, 'The effects of tidal buffering on acid sulphate soil environments in coastal areas of New South Wales', Geotechnical and Geological Engineering, vol. 20, no. 3, pp. 181-199.
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One-way floodgates installed on flood mitigation drains in regions affected by acid sulphate soils restrict carbonate bicarbonate buffering, thereby creating reservoirs of acid water (pH < 4.5) that discharge during the ebb tide. The drain water quality and hydrodynamic conditions prior to and following floodgate modifications that allowed for controlled saline intrusion are described with reference to data collected from intensively drained and floodgated coastal lowlands located in southeastern New South Wales, Australia. CI:SO4 ratios taken from ground-water samples depicted an acidic environment with little soil buffering capacity. Prior to modification, water quality upstream of the one-way floodgate was consistently acidic (average pH 4.6) with high concentrations of aluminum and iron that fluctuated with precipitation. Over a two-week period before modifications, floodgate leakage permitted alkaline water to intrude upstream of the floodgate and react with H+ ions. This period showed the strongest supporting field evidence for tidal buffering via modified floodgates. After installing vertical lifting, two-way floodgates average drain water pH increased to 5.89 and aluminum and iron concentrations decreased by more than 30%. A large rainfall (131.8 mm) during the post-modification period caused acidic groundwater flushing, however, in comparison to the pre-modification period, recovery time and average pH were markedly improved. Preliminary investigations of ground-water salinity in response to tidal intrusion has shown that electrical conductivity fluctuates with rainfall and it is predominately limited to 10 m perpendicular to the drain.
Indraratna, B, Price, J, Ranjith, P & Gale, W 2002, 'Some aspects of unsaturated flow in jointed rock', International Journal of Rock Mechanics and Mining Sciences, vol. 39, no. 5, pp. 555-568.
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Ji, JC & Leung, AYT 2002, 'Bifurcation control of a parametrically excited duffing system', NONLINEAR DYNAMICS, vol. 27, no. 4, pp. 411-417.
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A linear time-delayed feedback control is used to delay the occurrence of pitchfork bifurcations and to eliminate saddle-node bifurcations, which may arise in the nonlinear response of a parametrically excited Duffing system under the principal parametric resonance. The feedback gains and the time delay are chosen by analyzing the modulation equations of the amplitude and the phase. It is shown that by using an appropriate feedback control, the stable re,,ion of the trivial solutions can be broadened, a discontinuous bifurcation can be transformed into a continuous one, and the jump phenomenon in the resonance response can be removed.
Ji, JC & Leung, AYT 2002, 'Resonances of a non-linear s.d.o.f. system with two time-delays in linear feedback control', JOURNAL OF SOUND AND VIBRATION, vol. 253, no. 5, pp. 985-1000.
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The primary, superharmonic, and subharmonic resonances of a harmonically excited non-linear s.d.o.f. system with two distinct time-delays in the linear state feeback are studied. The two different time-delays are presented in the proportional feedback and the derivative feedback respectively. The method of multiple scales is utilized to obtain the first order approximation of response. The effect of the feedback gains and time-delays on the steady state responses of three types of resonances is investigated. It is found that a proper selection of the feedback gains and time-delays can enhance the control performance.
Li, J, Samali, B, Ye, L & Bakoss, S 2002, 'Behaviour of concrete beam–column connections reinforced with hybrid FRP sheet', Composite Structures, vol. 57, no. 1-4, pp. 357-365.
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Locke, M & Indraratna, B 2002, 'Filtration of broadly graded soils: the reduced PSD method', Géotechnique, vol. 52, no. 4, pp. 285-287.
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Mukhopadhyay, S, Kayal, JR, Khattri, KN & Pradhan, BK 2002, 'Simultaneous inversion of the aftershock data of the 1993 Killari earthquake in Peninsular India and its seismotectonic implications', PROCEEDINGS-INDIAN ACADEMY OF SCIENCES EARTH AND PLANETARY SCIENCES, vol. 111, no. 1, pp. 1-16.
Ponval, S, Pradhan, BK, Sharma, JK & Jain, SC 2002, 'Search and Render Algorithm for Three-dimensional Terrain Visualisation of Large Dataset', Defence Science Journal, vol. 52, no. 3, pp. 277-284.
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Sheng, D & Smith, DW 2002, '2D Finite Element Analysis of Multicomponent Contaminant Transport Through Soils', International Journal of Geomechanics, vol. 2, no. 1, pp. 113-134.
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This article presents a two-dimensional finite element method for the solution of the advection-dispersion transport equation for multicomponent contaminants. While the approach described is general, the analysis presented here is restricted to nonlinear, equilibrium-controlled sorption and exchange of soluble inorganic ions. The finite element method is based on a generalization of the onedimensional Transport-Equilibrium Petrov-Galerkin (TEPG) methods presented by Sheng and Smith [1]. In theTEPGmethods, the reaction term is treated as a part of the mass accumulation term. This is in contrast with common formulations where the reaction term is treated as a source term. The transport equation thus contains two unknowns, the aqueous concentration and the total analytical concentration. The solution strategy adopted is to solve the transport equations coupled with chemical equilibrium equations by sequential iteration. No assumption on the reaction term is required when solving the transport equation, which means the transport equation is always conservative. At the end of each time step, both the transport and chemical equilibrium equations are satisfied. To facilitate the solution of the transport equations that may be advection dominated, and optimal upwind weighting procedure and mid-point time stepping scheme are employed. A number of significant improvements are presented here beyond the TEPG methods presented by Sheng and Smith. These improvements included upwind weighting for a heterogeneous fluid velocity field, the solution of the chemical equilibrium equations for both adsorption and ion exchange, the introduction of an automatic time stepping scheme so as to maintain a predetermined accuracy, and the description of strategies to improve the efficiency of the numerical computations. The TEPG method described is used to analyse several problems with the Peclet number varying between zero and infinity. Both two-dimensional plane flow and axi-symmetric prob...
Sheng, D, Sloan, SW & Abbo, AJ 2002, 'An Automatic Newton‐Raphson Scheme', International Journal of Geomechanics, vol. 2, no. 4, pp. 471-502.
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This article presents an automatic Newton-Raphson method for solving nonlinear finite element equations. It automatically subincrements a series of given coarse load increments so that the local load path error in the displacements is held below a prescribed threshold. The local error is measured by taking the difference between two iterative solutions obtained from the backward Euler method and the SS21 method. By computing both the displacement rates and the displacements this error estimate is obtained cheaply. The performance of the new automatic scheme is compared with the standard Newton-Raphson scheme, the modified Newton-Raphson scheme with line search, and two other automatic schemes that are based on explicit Euler methods. Through analyses of a wide variety of problems, it is shown that the automatic Newton-Raphson scheme is superior to the standard Newton-Raphson methods in terms of efficiency, robustness, and accuracy. © 2003 ASCE.
Sloan, SW, Abbo, AJ & Sheng, D 2002, 'Erratum: Refined explicit integration of elastoplastic models with automatic error control (Engineering Computations (2001) 18 1/2 (121-54))', Engineering Computations (Swansea, Wales), vol. 19, no. 5-6, p. 594.
Sloan, SW, Abbo, AJ & Sheng, D 2002, 'Refined explicit integration of elastoplastic models with automatic error control (vol 18, pg 121, 2001)', ENGINEERING COMPUTATIONS, vol. 19, no. 5-6, pp. 594-594.
TULARAM, GA 2002, 'A Cylindrical Model of Pyrite Oxidation in Coastal Acidic Soils with Michaelis-Menten Uptake Kinetics', Environmental and Engineering Geoscience, vol. 8, no. 4, pp. 329-334.
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Zhang, X 2002, 'Prediction of short fatigue crack propagation behaviour by characterization of both plasticity and roughness induced crack closures', International Journal of Fatigue, vol. 24, no. 5, pp. 529-536.
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Abolhasan, M, Wysocki, T, Dutkiewicz, E, IEEE & IEEE 1970, 'Scalable routing strategy for dynamic zones-based MANETS', GLOBECOM'02: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-3, CONFERENCE RECORDS, GLOBECOM '02, IEEE, Taipei, Taiwan, pp. 173-177.
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This paper presents a new routing strategy for mobile ad hoc networks, called dynamic zone-based topology routing protocol (DZTR). We introduce new strategies to maintain up-to-date intrazone and interzone topology information at each node. We also propose a GPS-based location tracking mechanism, which reduces route discovery area and the number of nodes queried to find the required destination. Our routing strategy has been designed to work with a dynamic zone, which contains a set of member nodes. Every node outside a zone is called a single-state node. We perform theoretical performance analysis, which shows that our network topology creation process has significantly fewer overheads than flooding approaches.
Blumenstein, M 1970, 'Strategies for improving a Java-based, first year programming course', International Conference on Computers in Education, 2002. Proceedings., International Conference on Computers in Education, IEEE Comput. Soc, pp. 1095-1099.
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© 2002 IEEE. This paper describes the evolution of a first year Java course at Griffith University-Gold Coast since Semester 1, 2000 to the December 2002. The course was updated to emphasise program design and to implement and evaluate an "objects-as-needed" approach to first year programming. A number of strategies were tested to increase consistency amongst teaching staff, improve delivery of course resources, successfully cater to a wide variety of students and to enhance the learning experience in general. The success of the revised course has been measured by evaluating student feedback and performance. Currently, a focus group-based strategy of evaluation is being adopted to determine students' attitudes to the most recently implemented changes.
Halkon, B & Rothberg, S 1970, 'Comprehensive velocity sensitivity model for scanning and tracking laser vibrometry', Proceedings of SPIE - The International Society for Optical Engineering, 20th IMAC Conference on Structural Dynamics, SOC EXPERIMENTAL MECHANICS INC, LOS ANGELES, CA, pp. 1166-1170.
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Recent work set out a comprehensive analysis of the velocity sensed by a single laser vibrometer beam incident in an arbitrary direction on a target that is of substantial interest in engineering - a rotating shaft requiring three translational and three rotational co-ordinates to describe its vibratory motion fully. Six separate 'vibration sets', each a combination of motion parameters, appeared in the full expression for vibration velocity sensitivity and the difficulties associated with resolving individual vibration components within a complex motion were highlighted. One specific way in which the model has been extended is the subject of this paper. The scanning laser Doppler vibrometer has become an increasingly popular instrument especially for experimental modal analysis. Continuously scanning strategies, in which the laser beam orientation is a continuous function of time, have received considerable attention. Researchers have reported use of several different types of scan profile including a tracking profile in which the probe laser beam remains fixed on a single point on a target such as a rotating disc. When the velocity sensitivity model was originally reported, it was stated that it could be used with such applications and this is shown explicitly, for the first time, in this paper.
Halkon, B & Rothberg, SJ 1970, '<title>A comprehensive velocity sensitivity model for scanning and tracking laser Doppler vibrometry on rotating structures</title>', SPIE Proceedings, Fifth International Conference on Vibration Measurements by Laser Techniques, SPIE, ANCONA, ITALY, pp. 9-21.
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Recent work set out a comprehensive analysis of the velocity sensed by a single laser Doppler vibrometer beam incident in an arbitrary direction on a target that is of substantial interest in engineering - a rotating, shaft requiring three translational and three rotational co-ordinates to describe its vibratory motion fully. Six separate 'vibration sets', each a combination of motion parameters, appeared in the full expression for vibration velocity sensitivity and the difficulties associated with resolving individual vibration components within a complex motion were highlighted. The velocity sensitivity model can incorporate time dependent beam orientation and this is described in this paper with reference to scanning laser Doppler vibrometry. Continuously scanning strategies, in which the laser beam orientation is a continuous function of time, have recently received considerable attention, including a tracking profile in which the probe laser beam remains fixed on a single point on a target such as a rotating disc. Typically, one beam deflection mirror is driven using a cosine function whilst the other is driven with a sine function, resulting in a slightly elliptical beam trajectory. This and other more significant issues such as the effects of misalignment are easily accommodated in the velocity sensitivity model and a thorough analysis of their influence on the measured vibration signal is reported in this paper.
Huang, W, Sloan, S & Sheng, D 1970, 'Hypoplastic analysis of cone penetration in sands', Numerical Models in Geomechanics - 8th Proceedings of the International Symposium on Numerical Models in Geomechanics, NUMOG 2002, Taylor & Francis, pp. 607-612.
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© 2002 Swets & Zeitlinger, Lisse. This paper presents a rigorous numerical analysis of deep cone penetration in sand using a hypoplastic model. A tensor-valued function, which depends on the stress state and void ratio, is used to describe stress changes in the soil for a wide range of pressure levels. With the capability to model finite deformation in the soil and large sliding on the soil-penetrometer interface, the penetration process is modelled realistically. The dependence of cone resistance on the pressure and density state in the sand is the focus of the study.
LI, J & SAMALI, B 1970, 'VARIABLE STRUCTURE CONTROL OF SEISMICALLY EXCITED STRUCTURE WITH SHAPE MEMORY ALLOY ACTUATORS', Applied Mechanics, Proceedings of the Third Australasian Congress on Applied Mechanics, WORLD SCIENTIFIC, Sydney, Australia, pp. 665-670.
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Li, J, Samali, B & Chapman, C 1970, 'Experimental realisation of active control of a five storey building model using SMA actuators', Advances in Mechanics of Structures and Materials, The 17th Australasian Conference on the Mechanics of Structures and Materials, A.A. Balkema Publishers, Gold Coast, Australia, pp. 699-704.
Samali, B, Al Dawod, M & Li, JC 1970, 'PERFORMANCE OF AN ACTIVE MASS DRIVER SYSTEM ON A FIVE STOREY BENCHMARK MODEL', The Proceedings of the International Conference on Motion and Vibration Control, Japan Society of Mechanical Engineers, Japan, pp. 166-171.
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SAMALI, B, AL-DAWOD, M & LI, J 1970, 'PERFORMANCE OF A FIVE STOREY BENCHMARK MODEL USING AN ACTIVE MASS DRIVER AND A FUZZY CONTROLLER', Applied Mechanics, Proceedings of the Third Australasian Congress on Applied Mechanics, WORLD SCIENTIFIC, Gold Coast, Australia, pp. 647-652.
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Samali, B, Wu, Y & Li, J 1970, 'Torsional response of a base-isolated eccentric building model', Advances in Mechanics of Structures and Materials, The 17th Australasian Conference on the Mechanics of Structures and Materials, A.A. Balkema Publishers, Gold Coast, Australia, pp. 769-774.
WU, YM, SAMALI, B & LI, J 1970, 'EARTHQUAKE RESISTANT PERFORMANCE OF LAMINATED AND LEAD CORE RUBBER BEARINGS', Applied Mechanics, Proceedings of the Third Australasian Congress on Applied Mechanics, WORLD SCIENTIFIC, Sydney, Australia, pp. 659-664.
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