ORCID Profile
0000-0001-6420-2312
Current Organisations
CSIRO
,
CSIRO Australian Manufacturing and Materials Precinct
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Elsevier BV
Date: 10-2022
Publisher: Public Library of Science (PLoS)
Date: 08-09-2023
Publisher: Trans Tech Publications, Ltd.
Date: 05-01-2021
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.1016.1031
Abstract: Metal additive manufacturing based on powder bed fusion processes is increasingly important. However, highly transient physical phenomena that occur in these processes at different length scales are difficult to observe. Challenging and costly experiments are usually needed to obtain data for process understanding and improvement. Computational modelling of powder-bed fusion processes is therefore important from several points of view. These include better process understanding, optimisation of process parameters and component designs, prediction of component properties, qualification of components and to assist process control. Several physical processes have to be treated to develop a complete model, namely the raking of the powder bed surface, the transfer of energy from the laser or electron beam to the metal, the melting and solidification of the powder, the flow of liquid metal in the melt pool, the heat transfer from the melt pool to the surrounding powder and solid metal, the evolution of the microstructure, and the residual stress and deformation of the component. These processes occur at very different scales, and have to be treated using several different computational techniques. In addition, the interdependency of some of the processes has to be accounted for. This paper discusses the rationale for developing a complete model, progress in developing sub-models of the different physical processes, and the framework that is envisaged to combine the sub-models into a predictive model of the additive manufacturing process.
Publisher: Trans Tech Publications, Ltd.
Date: 07-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.693.235
Abstract: Wire rod is produced by hot-rolling a bar of metal coming from a wheel/belt continuous casting process. This kind of process, e.g. Properzi, is an elaborate process in which the molten metal is poured in a cooled rotating mould formed by the groove of a wheel and closed by a belt. In order to better understand the heat transfer phenomenon and solidified bar characteristics, depending on process parameters a three dimensional thermo-mechanical model has been developed. The model, based on the finite-element method, calculates the heat transfer coefficient of the air gap at the metal-mould interface as a function of the size of the gap determined by the bar contraction and wheel and belt thermal deformations. The air gap formation due to metal shrinkage and mould deformation is the main factor which determines the heat extraction. Wheel temperature measurements with thermocouple and belt temperature measurements with an infrared system were carried out to verify model results. Attempts were also made to measure a liquid pool profile using doping with copper rich alloy. The model shows the effect of the casting temperature and the rotation speed on the air gap formation and resulting temperature and stress fields. The model can be applied to issues such as maximising wheel and belt life and minimising solidification defects.
Publisher: SAGE Publications
Date: 16-05-2014
Abstract: In this paper, springback of anisotropic sheet based on the modified form of the asymmetric non-quadratic yield function (YLD96) for plane stress conditions due to Barlat et al. (Yield function development for aluminium alloy sheets. J Mech Phys Solids 1997 45: 1727–1763), suitable for describing mixed (isotropic and kinematic) hardening in aluminium alloy sheets under the Bauschinger Effect was compared with the results of tests. Simulation of uniaxial tensile and cyclic tests including both nonlinear isotropic and nonlinear kinematic hardening showed the necessity of including the Bauschinger effect in the constitutive equations at both small and large strains. Following the application to prediction of springback in draw bending of these alloys oriented in the rolling direction, draw-bending tests on AA2024-O and AA7075-O alloy sheets are described. The springback parameters of specimens with axes oriented at 45° and 90° to the rolling direction were measured and compared with prediction based on the modified form of the YLD96, which captured the hardening response at small and large strains when combined with the mixed hardening model, predicting springback in very good agreement with experimental results. The number of components of back stress used in this model depends on the nature of the nonlinear behaviour of the material. For alloys AA2024-O and AA7075-O, excellent agreement with experiments required the use of up to three nonlinear components of back stress. Prediction suggested values of friction consistent with published values and showed that friction inversely affected the radius of sidewall curl, but was not sensitive to lower and upper opening angle. This was consistent with the findings of Carden et al. (Measurement of springback. Int J Mech Sci 2002 44: 79–101), although those authors also reported that very low friction may increase springback in their proposed draw-bending test. The results confirmed the efficacy of the yield surface model based on YLD96, modified to include nonlinear isotropic and nonlinear kinematic hardening, for predicting deformation subject to the Bauschinger effect.
Publisher: Elsevier BV
Date: 03-2021
Publisher: AGHU University of Science and Technology Press
Date: 2022
Publisher: Trans Tech Publications, Ltd.
Date: 07-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.693.227
Abstract: Producing low-dross ingots has been a long-term goal in aluminium cast houses. The patented CASTfill technology [1] is a low-dross and high-productivity pouring system developed to fulfil this demand. This paper describes the research methods used during the development of CASTfill now in service at Boyne Smelters Limited (BSL) since August 2009. The importance of combining scientific modelling and testing procedures with process operability, maintainability and durability to ensure the success of new technology in a production facility is also highlighted. Ingot assessments showed that the latest CASTfill design greatly reduced dross generated during mould filling. Improved ingot packaging and reduced variation of ingot weights were also observed as the results of a more tranquil flow of molten aluminium through CASTfill and its uniquely modular design.
Publisher: AGHU University of Science and Technology Press
Date: 2022
Publisher: Elsevier BV
Date: 04-2017
Publisher: Trans Tech Publications, Ltd.
Date: 06-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.690.107
Abstract: This work aims to develop flow and thermal control methods for the high pressure die casting (HPDC) of very thin-walled aluminium components where thicknesses are predominantly less than 1 mm. One specific aim includes developing advanced modelling capability using CFD software to predict the complex structure of the metal flow in the die and the casting solidification. The modelling based on FLOW-3D started initially with a fluidity die study to establish several key parameters in HPDC modelling through experimental validation. A new test casting geometry has been designed in the form of a shallow tray with other features such as changes in curvature, fins and bosses. The casting thickness can be made variable in the die. The experimental work was conducted on a 250-tonne HPDC machine. Initial models of molten metal flow in the die cavity based on a runner design for casting thicknesses between 1.5 mm and 1 mm are presented. The detailed model required a very large mesh of very small elements, and more accurate physical parameters which may not have been previously available.
Publisher: Springer International Publishing
Date: 2017
Location: Australia
Location: Australia
No related grants have been discovered for Vu Thua Nguyen.