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Article
Publication date: 22 May 2008

Eligiusz W. Postek, Roland W. Lewis and David T. Gethin

This paper sets out to present developments of a numerical model of squeeze casting process.

536

Abstract

Purpose

This paper sets out to present developments of a numerical model of squeeze casting process.

Design/methodology/approach

The entire process is modelled using the finite element method. The mould filling, associated thermal and thermomechanical equations are discretized using the Galerkin method. The front in the filling analysis is followed using volume of fluid method and the advection equation is discretized using the Taylor Galerkin method. The coupling between mould filling and the thermal problem is achieved by solving the thermal equation explicitly at the end of each time step of the Navier Stokes and advection equations, which allows one to consider the actual position of the front of the filling material. The thermomechanical problem is defined as elasto‐visco‐plastic described in a Lagrangian frame and is solved in the staggered mode. A parallel version of the thermomechanical program is presented. A microstructural solidification model is applied.

Findings

During mould filling a quasi‐static Arbitrary Lagrangian Eulerian (ALE) is applied and the resulting temperatures distribution is used as the initial condition for the cooling phase. During mould filling the applied pressure can be used as a control for steering the distribution of the solidified fractions.

Practical implications

The presented model can be used in engineering practice. The industrial examples are shown.

Originality/value

The quasi‐static ALE approach was found to be applicable to model the industrial SQC processes. It was found that the staggered scheme of the solution of the thermomechanical problem could parallelize using a multifrontal parallel solver.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 18 no. 3/4
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 1 July 2006

Roland W. Lewis, Eligiusz W. Postek, Zhiqiang Han and David T. Gethin

To present a numerical model of squeeze casting process.

2119

Abstract

Purpose

To present a numerical model of squeeze casting process.

Design/methodology/approach

The modelling consists of two parts, namely, the mould filling and the subsequent thermal stress analysis during and after solidification. Mould filling is described by the Navier‐Stokes equations discretized using the Galerkin finite element method. The free surface is followed using a front tracking procedure. A thermal stress analysis is carried out, assuming that a coupling exists between the thermal problem and the mechanical one. The mechanical problem is described as an elasto‐visco‐plastic formulation in an updated Lagrangian frame. A microstructural solidification model is also incorporated for the mould filling and thermal stress analysis. The thermal problem is solved using enthalpy method.

Findings

During the mould‐filling process a quasi‐static arbitrary Lagrangian‐Eulerian (ALE) approach and a microstructural solidification model were found to be applicable. For the case of the thermal stress analysis the influence of gap closure, effect of initial stresses (geometric nonlinearity), large voids and good performance of a microstructural model have been demonstrated.

Research limitations/implications

The model can also be applied to the simulation of indirect castings. The final goal of the model is the ability to simulate the forming of the material after mould filling and during the solidification of the material. This is possible to achieve by applying arbitrary contact surfaces due to the sliding movement of the cast versus the punch and die.

Practical implications

The presented model can be used in engineering practice, as it incorporates selected second‐order effects which may influence the performance of the cast.

Originality/value

During the mould‐filling procedure a quasi‐static ALE approach has been applied to SQC processes and found to be generally applicable. A microstructural solidification model was applied which has been used for the thermal stress analysis only. During the thermal stress analysis the influence of gap closure and initial stresses (geometric nonlinearity) has been demonstrated.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 16 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 1 July 2006

Vaughan Voller

288

Abstract

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 16 no. 5
Type: Research Article
ISSN: 0961-5539

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