| Partner: David Gethin |
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Recent publications
| 1. | Postek E.♦, Lewis R.W.♦, Gethin D.T.♦, Finite element modelling of the squeeze casting process, INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT AND FLUID FLOW, ISSN: 0961-5539, DOI: 10.1108/09615530810853619, Vol.18, pp.325-355, 2008 Keywords: Finite element analysis, Thermodynamics, Material‐deforming processes Affiliations:
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| 2. | Lewis R.W.♦, Postek E.♦, Han Z.♦, Gethin D.T.♦, A finite element model of the squeeze casting process, INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT AND FLUID FLOW, ISSN: 0961-5539, Vol.16, No.5, pp.539-572, 2006 | | ||||||||||||
| 3. | Postek E.♦, Lewis R.W.♦, Gethin D.T.♦, Ransing R.S.♦, Influence of initial stresses on the cast behaviour during squeeze forming processes, JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, ISSN: 0924-0136, DOI: 10.1016/j.jmatprotec.2004.05.022, Vol.159, No.3, pp.338-346, 2005 Abstract: This paper deals with the evaluation of the effects of initial stresses developed during the pressurized casting process. The stresses are induced by the external pressure applied to the cast and developed due to thermal loading. The effect of the stresses is considered as a second order effect by means of investigating the influence of the ‘geometric’ or ‘initial stresses’ stiffness matrix on the response of the cast. The problem formulation is done in the updated Lagrangian (UL) frame. An implicit time integration scheme is applied to solve the transient thermomechanical problem in a staggered form. The constitutive mechanical model is elasto-viscoplastic with hardening incorporated with a Mises yield function. The finite element method is employed and a few 3D numerical examples are presented. Keywords:Squeeze casting, Initial stresses, Coupled problems, Finite elements Affiliations:
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Conference papers
| 1. | Lewis R.W.♦, Postek E., Gethin D.T.♦, Yang X.S.♦, Pao W.K.S.♦, Chao L.♦, Numerical methods in simulation of industrial processes, AET2006, First International Conference on Advances in Engineering and Technology, 2006-07-16/07-19, Entebbe (UG), pp.764-795, 2006 Abstract: The paper deals with an overview of some industrial applications leading to a formulation for advanced numerical techniques. The applications comprise squeeze casting processes, forming of tablets and petroleum reservoir modelling. All of the problems lead to solutions of highly nonlinear, coupled sets of multiphysics equations. Keywords:squeeze forming, powder compaction, oil fields, coupled problems, thermomechanics, porous media, fluid flow, nonlinear solid mechanics, phase transformations, microstructural solidification models, numerical methods, contact problems, discrete elements, finite elements. Affiliations:
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| 2. | Ahmad R.♦, Gethin D.T.♦, Lewis R.W.♦, Ransing R.S.♦, Postek E., Thermal optimisation of the squeeze-forming process using genetic algorithms, 3rd M.I.T Conference on Computational Fluid and Solid Mechanics, 2005-06-14/06-17, Boston (US), pp.1205-1208, 2005 | | ||||||||||||||||||
| 3. | Lewis R.W.♦, Postek E., Gethin D.T.♦, Ransing R.S.♦, A model of microstructural solidification during mould filling for squeeze forming processes, 4th International Conference on Computational Heat and Mass Transfer, 2005-05-17/05-20, Cachan (FR), pp.1122-1125, 2005 | |
Conference abstracts
| 1. | Ahmad R.♦, Gethin D.T.♦, Lewis R.W.♦, Postek E., Design sensitivity of a sequentially coupled problem: casting, ACME 2004, 12th Association of Computational Mechanics in Engineering Annnual Conference, 2004-04-05/04-06, Cardiff (GB), pp.1-4, 2004 Abstract: The presented paper deals with the design sensitivity of a sequentially coupled thermo-mechanical problem. The key finding is to provide a tool for optimisation software (analytical design sensitivity gradients) for a sequentially coupled thermal-mechanical problem. Keywords:casting process, thermomechanics, parameter sensitivity analysis Affiliations:
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| 2. | Postek E.W., Lewis R.W.♦, Gethin D.T.♦, Ransing R.S.♦, Finite element model of mould filling during squeeze forming processes, ACME 2004, 12th Association of Computational Mechanics in Engineering Annnual Conference, 2004-04-05/04-06, Cardiff (GB), pp.1-4, 2004 Abstract: During mould filling due to decreasing of liquidus temperature takes place solidification pocess. The paper deals mostly with a presentation of an application of a microstructural solidification model. The Navier Stokes equation describing the flow problem is solved using Taylor Galerkin method. Keywords:mould filling, microstructural solidification, thermomechanics Affiliations:
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| 3. | Dong L.L.♦, Lewis R.W.♦, Gethin D.T.♦, Postek E.W., Simulation of deformation of ductile pharmaceutical particles with finite element method, ACME 2004, 12th Association of Computational Mechanics in Engineering Annnual Conference, 2004-04-05/04-06, Cardiff (GB), pp.1-5, 2004 Abstract: In order to guarantee the strength and thus the quality of the tablets produced during the tabletting process, it is essential to understand the deforming characteristics of excipient binders. The present numerical work is motivated to provide an insight into the mechanical behaviour of the particle deformation of the excipient binder. In the present study pregelatinised starch is selected, which is known to behave in a ductile manner during compaction. An elasto-viscoplastic material model has been selected in the present study to simulate the deformation behaviour of the pregelatinised starch. Elasto-viscoplastic model 1S chosen because all the plastic deformation exhibits rate-dependency to some extent, and it is a well-developed model for simulating non-linear deformation which has been studied for four decades (Perzyna (1966), Zabaras and Arif (l992)). Keywords:discrete element method, finite element method, viscoplasticity, adaptive meshing Affiliations:
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