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1 – 10 of 117
Article
Publication date: 1 May 1994

N. Brännberg and J. Mackerle

This paper gives a review of the finite element techniques (FE)applied in the area of material processing. The latest trends in metalforming, non‐metal forming and powder…

1450

Abstract

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming and powder metallurgy are briefly discussed. The range of applications of finite elements on the subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for the last five years, and more than 1100 references are listed.

Details

Engineering Computations, vol. 11 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 August 1998

Jaroslav Mackerle

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder…

4533

Abstract

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder metallurgy and composite material processing are briefly discussed. The range of applications of finite elements on these subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE researchers/users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for 1994‐1996, where 1,370 references are listed. This bibliography is an updating of the paper written by Brannberg and Mackerle which has been published in Engineering Computations, Vol. 11 No. 5, 1994, pp. 413‐55.

Details

Engineering Computations, vol. 15 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 October 1995

R.L. McAdie, J.T. Cross, R.W. Lewis and D.T. Gethin

A rigorous Finite Element (FE) formulation based on an enthalpytechnique is developed for solving coupled nonlinear heat conduction/massdiffusion problems with phase change. The…

Abstract

A rigorous Finite Element (FE) formulation based on an enthalpy technique is developed for solving coupled nonlinear heat conduction/mass diffusion problems with phase change. The FE formulation consists of a fully coupled heat conduction and solute diffusion formulation, with solid‐liquid phase change, where the effects of pressure and convection are neglected. A full enthalpy method is employed eliminating singularities which result from abrupt changes in heat capacity at the phase interfaces. The FE formulation is based on the fixed grid technique where the elements are two dimensional, four noded quadrilaterals with the primary variables being enthalpy and average solute concentration. Temperature and solid mass fraction are calculated on a local level at each integration point of an element. A fully consistent Newton‐Raphson method is used to solve the global coupled equations and an Euler backward difference scheme is used for the temporal discretization. The solution of the enthalpy‐temperature relationship is carried out at the integration points using a Newton‐Raphson method. A secant method employing the regula falsi technique takes into account sudden jumps or sharp changes in the enthalpy‐temperature behaviour which occur at the phase zone interfaces. The Euler backward difference integration rule is used to calculate the solid mass fraction and its derivatives. A practical example is analysed and results are presented.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 5 no. 10
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 February 2024

Vishal Singh and Arvind K. Rajput

The present paper aims to analyse the synergistic effect of pocket orientation and piezo-viscous-polar (PVP) lubrication on the performance of multi-recessed hybrid journal…

Abstract

Purpose

The present paper aims to analyse the synergistic effect of pocket orientation and piezo-viscous-polar (PVP) lubrication on the performance of multi-recessed hybrid journal bearing (MHJB) system.

Design/methodology/approach

To simulate the behaviour of PVP lubricant in clearance space of the MHJB system, the modified form of Reynolds equation is numerically solved by using finite element method. Galerkin’s method is used to obtain the weak form of the governing equation. The system equation is solved by Gauss–Seidal iterative method to compute the unknown values of nodal oil film pressure. Subsequently, performance characteristics of bearing system are computed.

Findings

The simulated results reveal that the location of pressurised lubricant inlets significantly affects the oil film pressure distribution and may cause a significant effect on the characteristics of bearing system. Further, the use of PVP lubricant may significantly enhances the performance of the bearing system, namely.

Originality/value

The present work examines the influence of pocket orientation with respect to loading direction on the characteristics of PVP fluid lubricated MHJB system and provides vital information regarding the design of journal bearing system.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2023-0241/

Details

Industrial Lubrication and Tribology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 May 2000

T.P. Sperring, D.T. Gethin and J.O. Medwell

A combined experimental and numerical investigation into the fluid flow and heat transfer processes that take place in the spray deposition of tubular preforms is presented. The…

Abstract

A combined experimental and numerical investigation into the fluid flow and heat transfer processes that take place in the spray deposition of tubular preforms is presented. The work is concerned principally with impingement mechanisms at jet diameter to target distances that are large in comparison with previous reported studies. The experimental investigation required the design of a novel heat transfer meter that was capable of resolving the heat transfer coefficient within 2.5 per cent. The experiments gave a new correlation for stagnation heat transfer, similar in form to correlations that have been published for small jet diameter to target distance values. The experiments also showed the presence of skewing of the heat transfer coefficient in the deposition zone due to its tapered nature. A finite volume based model of the deposition chamber was developed and run to compare with the experimental data. This model was found to yield trends similar to those measured experimentally, thus confirming its qualitative capability. However the absolute values of heat transfer coefficient that were computed were significantly lower than measured values. This points to the requirement to consider alternative computing schemes and to investigate the methods of representing the heat transfer mechanisms at the physical boundaries, particularly at the preform surface.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 10 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

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.

2096

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

Article
Publication date: 1 March 1986

J.O. Medwell, T.D. Gethin, C. Taylor and J. Rance

A method is presented for the determination of secondary flow fields in three practical examples. In one, the flow is laminar and the other two turbulent. The latter were analysed…

Abstract

A method is presented for the determination of secondary flow fields in three practical examples. In one, the flow is laminar and the other two turbulent. The latter were analysed using a one‐equation or two‐equation model of turbulence in conjunction with the equations of motion. Methods of improving the boundary condition for secondary flow prediction by introducing a ‘slip’ condition at near wall locations are referred to, and its effect demonstrated. Finally, a fluid film of extremely high aspect ratio and in laminar motion was investigated and the existence of recirculatory flow pockets predicted.

Details

Engineering Computations, vol. 3 no. 3
Type: Research Article
ISSN: 0264-4401

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.

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

Article
Publication date: 1 May 1999

R.S. Ransing, R.W. Lewis and D.T. Gethin

Heat transfer across the metal‐mould interface has been modelled by a generalized equation referred to as the Lewis‐Ransing Correlation. It has been shown that the spatial as well…

Abstract

Heat transfer across the metal‐mould interface has been modelled by a generalized equation referred to as the Lewis‐Ransing Correlation. It has been shown that the spatial as well as temporal variation of the interfacial heat transfer coefficient can be optimally designed to achieve a desired solidification pattern. The technique has been validated on two practical examples achieving a complex solidification pattern.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 9 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 May 2001

R.W. Lewis, M.T. Manzari and D.T. Gethin

The general procedure of thermal optimisation in the sand casting process is addressed. Various aspects of design including the size and position of feeders and chills are…

1458

Abstract

The general procedure of thermal optimisation in the sand casting process is addressed. Various aspects of design including the size and position of feeders and chills are discussed and practical approaches are presented to search for optimum design configurations. An algorithm is also presented for finding the optimum size, position and number of chills in a sand casting process. The presence of the chill(s) in the casting configuration is simulated using a one‐dimensional heat conduction model and proper inter‐facial heat transfer coefficients. The method is efficient as all computations are carried out on the same grid and there is no need for re‐meshing due to re‐sizing or re‐positioning of the chills. A finite element thermal analysis module is linked to a commercial optimisation tool to search for the optimum set of design variables and a computationally efficient sensitivity analysis method is introduced. Three sand casting test cases are solved to validate and demonstrate the optimisation procedure and these show its use to determine the optimum size, location and number of feeders and chills on a section through a casting.

Details

Engineering Computations, vol. 18 no. 3/4
Type: Research Article
ISSN: 0264-4401

Keywords

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