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Article
Publication date: 27 June 2008

Junye Wang, Xiaoxian Zhang, Anthony G. Bengough and John W. Crawford

The cell‐based method of domain decomposition was first introduced for complex 3D geometries. To further assess the method, the aim is to carry out flow simulation in…

Abstract

Purpose

The cell‐based method of domain decomposition was first introduced for complex 3D geometries. To further assess the method, the aim is to carry out flow simulation in rectangular ducts to compare the known analytical solutions.

Design/methodology/approach

The method is not based on equal subvolumes but on equal numbers of active cells. The variables of the simulation are stored in ordered 1D arrays to replace the conventional 3D arrays, and the domain decomposition of the complex 3D problems therefore becomes 1D. Finally, the 3D results can be recovered using a coordinate matrix. Through the flow simulation in the rectangular ducts how the algorithm of the domain decompositions works was illustrated clearly, and the numerical solution was compared with the exact solutions.

Findings

The cell‐based method can find the subdomain interfaces successfully. The parallelization based on the algorithm does not cause additional errors. The numerical results agree well with the exact solutions. Furthermore, the results of the parallelization show again that domains of 3D geometries can be decomposed automatically without inducing load imbalances.

Practical implications

Although, the approach is illustrated with lattice Boltzmann method, it is also applicable to other numerical methods in fluid dynamics and molecular dynamics.

Originality/value

Unlike the existing methods, the cell‐based method performs the load balance first based on the total number of fluid cells and then decomposes the domain into a number of groups (or subdomains). Thus, the task of the cell‐based method is to recover the interface rather than to balance the load as in the traditional methods. This work has examined the celled‐based method for the flow in rectangular ducts. The benchmark test confirms that the cell‐based domain decomposition is reliable and convenient in comparison with the well‐known exact solutions.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 18 no. 5
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 1 July 2001

Janet Efstathiou and Peter Golby

Manufacturing facilities may simplify their operations by converting from a process‐based layout to manufacturing cells. Mathematically, many possible configurations of…

Abstract

Manufacturing facilities may simplify their operations by converting from a process‐based layout to manufacturing cells. Mathematically, many possible configurations of cells exist, so it may prove computationally infeasible to analyse them all. Also, some current methods of cell design do not take account of the pattern of demand of the existing products or the sequence of the operations that are performed on the products. Presents a simple method of designing manufacturing cells, which uses product demand and operations sequence to design feasible cells, while remaining computationally simple. The method uses a standard spreadsheet tool, so is accessible to a wide range of manufacturing facilities. The method is illustrated with an actual application to a press shop manufacturing over 200 products on 20 presses.

Details

Integrated Manufacturing Systems, vol. 12 no. 4
Type: Research Article
ISSN: 0957-6061

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Article
Publication date: 1 August 2002

Hassan M. Selim

The design of a cellular manufacturing system requires that a machine population be partitioned into machine groups called manufacturing cells. A new graph partitioning…

Abstract

The design of a cellular manufacturing system requires that a machine population be partitioned into machine groups called manufacturing cells. A new graph partitioning heuristic is proposed to solve the manufacturing cell formation problem (MCFP). In the proposed heuristic, The MCFP is represented by a graph whose node set represents the machine cluster and edge set represents the machine‐pair association weights. A graph partitioning approach is used to form the manufacturing cells. This approach offers improved design flexibility by allowing a variety of design parameters to be controlled during cell formation. The effectiveness of the heuristic is demonstrated by comparing it to two MCFP published solution methods using several problems from the literature.

Details

Industrial Management & Data Systems, vol. 102 no. 6
Type: Research Article
ISSN: 0263-5577

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Article
Publication date: 1 December 2000

Y. Bernard, E. Mendes and Z. Ren

A new method for the determination of the classical Preisach’s model distribution function is developed. The proposed method determines numerically the distribution…

Abstract

A new method for the determination of the classical Preisach’s model distribution function is developed. The proposed method determines numerically the distribution function from classical experimental measurements and does not make any assumption concerning the material type. The Preisach’s triangle is discretised in a finite set of cells (about 200 cells are needed). Two ways for the determination of the discretised distribution function are presented. The first assumes constant distribution function value in each cell. The second determines the nodal values of the discretised distribution function and uses a bilinear interpolation technique to obtain the distribution function in any position of the Preisach’s triangle. We also show that the proposed method can also be used to model the inverse distribution function. The comparison between modelled and experimental hysteresis curves for both major and minor cycles have shown the effectiveness of the proposed method.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 19 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 24 October 2008

Hamdi A. Bashir and Samir Karaa

Without reliance on results obtained from applying a cell formation method, this paper aims to describe a simple quantitative approach to testing whether an underlying…

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607

Abstract

Purpose

Without reliance on results obtained from applying a cell formation method, this paper aims to describe a simple quantitative approach to testing whether an underlying pattern of relationships exists between machines of a given system, such that the machines may be rearranged into manufacturing cells. It also aims to support the approach by an index for measuring the clustering tendency.

Design/methodology/approach

The eigenvalues of the similarity coefficient matrix and Kaiser's rule are used to: detect the number of clusters existing in the part‐machine matrix, and derive an index for predicting the goodness of the best possible obtainable cell formation.

Findings

The results of applying the proposed approach and the clustering tendency index to problems of different sizes taken from the literature have proven that both the approach and the clustering tendency index are powerful in performing the feasibility assessment and in predicting the right number of manufacturing cell to be formed.

Practical implications

This study is of considerable value to practitioners because it provides them with a powerful yet very easy to apply approach for assessing the feasibility of adopting cellular manufacturing in early stages of design. Another characteristic of this approach is the possibility of using it as a decision support tool for practitioners who opt to use a cell formation method which requires specifying the number of cells in advance. Moreover, the approach does not require any special software package, since it can be easily performed using several available software packages such as MATLAB and Mathematica.

Originality/value

A methodology for evaluating the adaptability of a system to cellular manufacturing has been proposed in a previous study. However, the methodology used is complex and uses a certain degree of subjectivity. In contrast, the proposed approach is simple and completely quantitative. Furthermore, a new index for measuring the clustering tendency is presented.

Details

Journal of Manufacturing Technology Management, vol. 19 no. 8
Type: Research Article
ISSN: 1741-038X

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Article
Publication date: 1 July 2005

Jaydeep Balakrishnan and Chun Hung Cheng

The purpose of this research paper is to discuss cellular manufacturing is discussed under conditions of changing product demand. Traditional cell formation procedures…

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1743

Abstract

Purpose

The purpose of this research paper is to discuss cellular manufacturing is discussed under conditions of changing product demand. Traditional cell formation procedures ignore any changes in demand over time from product redesign and other factors. However given that in today's business environment, product life cycles are short, a framework is proposed that creates a multi‐period cellular layout plan including cell redesign where appropriate.

Design/methodology/approach

The framework is illustrated using a two‐stage procedure based on the generalized machine assignment problem and dynamic programming. This framework is conceptually compared to virtual cell manufacturing, which is useful when there is uncertainty in demand rather than anticipated changes in demand. A case study is used to explain how the concept would work in practice.

Findings

One major characteristic of the proposed method is that it is flexible enough to incorporate existing cell formation procedures. It is shown through an example problem that the proposed two‐stage method is better than undergoing ad hoc layout changes or ignoring the demand changes when shifting or cell rearrangement costs exist. It also sheds some insight into cellular manufacturing under dynamic conditions.

Originality/value

This paper should be useful to both researchers and practitioners who deal with demand changes in cellular manufacturing.

Details

Journal of Manufacturing Technology Management, vol. 16 no. 5
Type: Research Article
ISSN: 1741-038X

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Article
Publication date: 1 January 2006

N. Geren, M. Çakirca and M. Bayramoğlu

To design a flexible integrated robotic assembly and rework (remanufacturing) cell for assembly, selective assembly and rework of advanced surface mount components (SMCs…

Abstract

Purpose

To design a flexible integrated robotic assembly and rework (remanufacturing) cell for assembly, selective assembly and rework of advanced surface mount components (SMCs) using the generic methodology developed in this paper.

Design/methodology/approach

Manual rework procedures are investigated for all advanced SMCs. General and specific component‐related rework considerations are obtained and necessary tooling candidates for automation are determined. This is followed by determination of the specific automated rework procedure and selection of suitable tooling for automated robotic rework and generation and evaluation of design concepts.

Findings

The developed methodology, which considers the reflow tool at the centre of the development process, has worked well in designing a flexible integrated robotic assembly and rework cell.

Practical implications

This study identified the rework requirements for advanced SMCs, the essential features for rework reflow tools, criteria for comparing reflow tools, and a generic procedure for design and concept selection.

Originality/value

It provides valuable knowledge for designers of flexible integrated robotic assembly and rework cells for assembly, selective assembly and rework of advanced SMCs.

Details

Soldering & Surface Mount Technology, vol. 18 no. 1
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 13 May 2014

Timothy Hart and Paul Zandbergen

The purpose of this paper is to examine the effects of user-defined parameters settings (e.g. interpolation method, grid cell size, and bandwidth) on the predictive…

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3757

Abstract

Purpose

The purpose of this paper is to examine the effects of user-defined parameters settings (e.g. interpolation method, grid cell size, and bandwidth) on the predictive accuracy of crime hotspot maps produced from kernel density estimation (KDE).

Design/methodology/approach

The influence of variations in parameter settings on prospective KDE maps is examined across two types of interpersonal violence (e.g. aggravated assault and robbery) and two types of property crime (e.g. commercial burglary and motor vehicle theft).

Findings

Results show that interpolation method has a considerable effect on predictive accuracy, grid cell size has little to no effect, and bandwidth as some effect.

Originality/value

The current study advances the knowledge and understanding of prospective hotspot crime mapping as it answers the calls by Chainey et al. (2008) and others to further investigate the methods used to predict crime.

Details

Policing: An International Journal of Police Strategies & Management, vol. 37 no. 2
Type: Research Article
ISSN: 1363-951X

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Article
Publication date: 18 April 2016

Yunlong Tang and Yaoyao Fiona Zhao

This paper aims to provide a comprehensive review of the state-of–the-art design methods for additive manufacturing (AM) technologies to improve functional performance.

Downloads
2377

Abstract

Purpose

This paper aims to provide a comprehensive review of the state-of–the-art design methods for additive manufacturing (AM) technologies to improve functional performance.

Design/methodology/approach

In this survey, design methods for AM to improve functional performance are divided into two main groups. They are design methods for a specific objective and general design methods. Design methods in the first group primarily focus on the improvement of functional performance, while the second group also takes other important factors such as manufacturability and cost into consideration with a more general framework. Design methods in each groups are carefully reviewed with discussion and comparison.

Findings

The advantages and disadvantages of different design methods for AM are discussed in this paper. Some general issues of existing methods are summarized below: most existing design methods only focus on a single design scale with a single function; few product-level design methods are available for both products’ functionality and assembly; and some existing design methods are hard to implement for the lack of suitable computer-aided design software.

Practical implications

This study is a useful source for designers to select an appropriate design method to take full advantage of AM.

Originality/value

In this survey, a novel classification method is used to categorize existing design methods for AM. Based on this classification method, a comprehensive review is provided in this paper as an informative source for designers and researchers working in this field.

Details

Rapid Prototyping Journal, vol. 22 no. 3
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 26 July 2021

Francesco Capizzano and Triyantono Sucipto

This paper aims to describe a research effort towards the comprehension of the unsteady phenomena due to the deployment of high-lift devices at approach/landing conditions.

Abstract

Purpose

This paper aims to describe a research effort towards the comprehension of the unsteady phenomena due to the deployment of high-lift devices at approach/landing conditions.

Design/methodology/approach

The work starts from a preexisting platform based on an immersed boundary (IB) method whose capabilities are extended to study compressible and viscous flows around moving/deforming objects. A hybrid Lagrangian-Eulerian approach is designed to consider the motion of multiple bodies through a fixed Cartesian mesh. That is, the cells’ volumes do not move in space but rather they observe the solid walls crossing themselves. A dynamic discrete forcing makes use of a moving least-square procedure which has been validated by simulating well-known benchmarks available for rigid body motions. Partitioned fluid-structure interactions (FSI) strategies are explored to consider aeroelastic phenomena. A shared platform, between the aerodynamic and the structural solvers, fulfils the loads’ transfer and drives the sequence of the operating steps.

Findings

The first part of the results is devoted to a basic two-dimensional study aiming at evaluating the accuracy of the method when simple rigid motions are prescribed. Afterwards, the paper discusses the solution obtained when applying the dynamic IB method to the rigid deployment of a Krueger-flap. The final section discusses the aeroelastic behaviour of a three-element airfoil during its deployment phase. A loose FSI coupling is applied for estimating the possible loads’ downgrade.

Research limitations/implications

The IB surfaces are allowed to move less than one IB-cell size at each time-step de-facto restricting the Courant-Friedrichs-Lewy (CFL) based on the wall velocity to be smaller than unity. The violation of this constraint would impair the explicit character of the method.

Practical implications

The proposed method improves automation in FSI numerical analysis and relaxes the human expertise/effort for meshing the computational domain around complex three-dimensional geometries. The logical consequence is an overall speed-up of the simulation process.

Originality/value

The value of the paper consists in demonstrating the applicability of dynamic IB techniques for studying high-lift devices. In particular, the proposed Cartesian method does not want to compete with body-conforming ones whose accuracy remains generally superior. Rather, the merit of this research is to propose a fast and automatic simulation system as a viable alternative to classic multi-block structured, chimaera or unstructured tools.

Details

Aircraft Engineering and Aerospace Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1748-8842

Keywords

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