Institute of Fundamental Technological Research
Polish Academy of Sciences

Partners

Richard Lewis

University of Wales (GB)

Recent publications

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:

Postek E.	-	other affiliation
Lewis R.W.	-	University of Wales (GB)
Gethin D.T.	-	University of Wales Swansea (GB)

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

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:

Postek E.	-	other affiliation
Lewis R.W.	-	University of Wales (GB)
Gethin D.T.	-	University of Wales Swansea (GB)
Ransing R.S.	-	other affiliation

Conference papers

1.	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
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

Conference abstracts

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: