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Article
Publication date: 3 July 2017

Jerzy Golebiowski and Marek Zareba

The purpose of this article is investigating the impact of the spatially variable heat transfer coefficient on the thermal field in the double insulated wire.

Abstract

Purpose

The purpose of this article is investigating the impact of the spatially variable heat transfer coefficient on the thermal field in the double insulated wire.

Design/methodology/approach

The effect of the air boundary layer was modelled by means of changing the total heat transfer coefficient on the external perimeter of the wire. This leads to an elliptical boundary problem with Hankel’s condition dependent on the angular coordinate. The eigenfunctions of the problem were determined analytically. On the other hand, the unknown coefficients of eigenfunctions and the constants were calculated numerically by solving a respective system of algebraic equations. The steady state current rating was determined with an iterative method.

Findings

By means of the presented method, the thermal field distribution deprived of axial symmetry in the double insulated wire was determined. The obtained results have good physical interpretation and were verified with the finite element method (by means of NISA v. 16 software). The determined values of the steady-state current rating were compared with those calculated by means of the equivalent heat transfer coefficient method and the International Electrotechnical Commission (IEC) standard.

Research limitations/implications

The method is applied to analyse scalar fields in layered cylindrical structures. This could be expanded to the case of a wire of any number of insulation layers. What is more, one could also consider heat sources without axial symmetry and located within the external area.

Originality/value

The analytical method of determining a thermal field deprived of axial symmetry in heterogeneous cylindrical system (the wire composed of three different materials) was developed.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 1 January 2013

Raid Al‐Aomar, Bashar El‐Khasawneh and Sinan Obaidat

Time standards are essential to plan and analyze manufacturing processes. A key element of process planning that is not generated from a typical computer‐aided process…

Abstract

Purpose

Time standards are essential to plan and analyze manufacturing processes. A key element of process planning that is not generated from a typical computer‐aided process plan (CAPP) is the process time standards. Generative process planning that includes time standards is particularly needed in the construction steel building (CSB) industry due to variability in projects (orders) size and content. Hence, the purpose of this paper is to focus on incorporating time standards into CAPP of CSB.

Design/methodology/approach

Empirical formulas are developed to generate time standards for variant steel beams based on their CAD files (design parameters and geometry) and process parameters (operational conditions). A Motion and Time Study (MTS) is used to estimate times for manual work elements such as load/unload activities and to validate the generated time standards. A generic parametric model is developed with Excel and integrated into the CAPP system to automatically estimate the standard time of each process operation.

Findings

Results showed that developing the time standards module for process operations and integrating its spreadsheets into a generative CAPP has helped process planners to arrive at better estimates of process parameters and has helped production management and the overall project management process in CSB industry.

Practical implications

The application of the proposed approach is not limited to CSB industry but it can also contribute to the continuing growth of CAPP applications in other industries.

Originality/value

The study is unique since it incorporates time standards into the architecture of CAPP system for accurate time and cost estimation and effective resource allocation and project management and it utilizes motion and time study (MTS) to collect complementary process data and validate the model‐generated cycle times.

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Article
Publication date: 17 April 2020

Wei Liu, Zhengdong Huang and Yunhua Liu

The purpose of this study is to propose an isogeometric analysis (IGA) approach for solving the Reynolds equation in textured piston ring cylinder liner (PRCL) contacts.

Abstract

Purpose

The purpose of this study is to propose an isogeometric analysis (IGA) approach for solving the Reynolds equation in textured piston ring cylinder liner (PRCL) contacts.

Design/methodology/approach

The texture region is accurately and conveniently expressed by non-uniform rational B-splines (NURBS) besides hydrodynamic pressure and the oil film density ratio is represented in this mathematical form. A quadratic programming method combined with a Lagrange multiplier method is developed to address the cavitation issue.

Findings

The comparison with the results solved by an analytical method has verified the effectiveness of the proposed approach. In the study of the PRCL contact with two-dimensional circular dimple textures, the solution of the IGA approach shows high smoothness and accuracy, and it well satisfies the complementarity condition in the case of cavitation presence.

Originality/value

This paper proposes an IGA approach for solving the Reynolds equation in textured PRCL contacts. Its novelty is reflected in three aspects. First, NURBS functions are simultaneously used to express the solution domain, texture shape, hydrodynamic pressure and oil density ratio. Second, the streamline upwind/Petrov–Galerkin method is adopted to create a weak form for the Reynolds equation that takes the oil density ratio as a first-order unknown variable. Third, a quadratic programming approach is developed to impose the complementarity conditions between the hydrodynamic pressure and the oil density ratio.

Details

Engineering Computations, vol. 37 no. 9
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 30 October 2018

Chensen Ding, Xiangyang Cui, Guanxin Huang, Guangyao Li, K.K. Tamma and Yong Cai

This paper aims to propose a gradient-based shape optimization framework in which traditional time-consuming conversions between computer-aided design and computer-aided

Abstract

Purpose

This paper aims to propose a gradient-based shape optimization framework in which traditional time-consuming conversions between computer-aided design and computer-aided engineering and the mesh update procedure are avoided/eliminated. The scheme is general so that it can be used in all cases as a black box, no matter what the objective and/or design variables are, whilst the efficiency and accuracy are guaranteed.

Design/methodology/approach

The authors integrated CAD and CAE by using isogeometric analysis (IGA), enabling the present methodology to be robust and accurate. To overcome the difficulty in evaluating the sensitivities of objective and/or constraint functions by analytic method in some cases, the authors adopt the finite difference method to calculate these sensitivities, thereby providing a universal approach. Moreover, to further eliminate the inefficiency caused by the finite difference method, the authors advance the exact reanalysis method, the indirect factorization updating (IFU), to exactly and efficiently calculate functions and their sensitivities, which guarantees its generality and efficiency at the same time.

Findings

The proposed isogeometric gradient-based shape optimization using our IFU approach is reliable and accurate, as well as general and efficient.

Originality/value

The authors proposed a gradient-based shape optimization framework in which they first integrate IGA and the proposed exact reanalysis method for applicability to structural response and sensitivity analysis.

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Article
Publication date: 1 February 1987

J.P. Monniot, D.J. Rhodes, D.R. Towill and J.G. Waterlow

This monograph examines research needs in computer aided production management (CAPM). Recommendations for future research and its organisation are made. The monograph is…

Abstract

This monograph examines research needs in computer aided production management (CAPM). Recommendations for future research and its organisation are made. The monograph is based on an in‐depth study of current CAPM practice in a varied sample of 33 companies. The study conclusions confirm many existing beliefs. Many companies are paying inadequate attention to the necessary prerequisites for successful CAPM implementation. The prerequisites change as the extent of CAPM system integration increases. Organisational rather than implementation issues dominate as integration increases. The proposed research would bring together existing knowledge of best CAPM practice to form methodologies for the audit, design and implementation of CAPM systems. The aim is to reduce the time‐span of the learning curve required for successful CAPM integration. The methodologies need to be specific to particular industrial sectors.

Details

International Journal of Operations & Production Management, vol. 7 no. 2
Type: Research Article
ISSN: 0144-3577

Keywords

Content available
Article
Publication date: 30 October 2020

Jiao-Long Zhang, Xian Liu, Yong Yuan, Herbert A. Mang and Bernhard L.A. Pichler

Transfer relations represent analytical solutions of the linear theory of circular arches, relating each one of the kinematic and static variables at an arbitrary…

Abstract

Purpose

Transfer relations represent analytical solutions of the linear theory of circular arches, relating each one of the kinematic and static variables at an arbitrary cross-section to the kinematic and static variables at the initial cross-section. The purpose of this paper is to demonstrate the significance of the transfer relations for structural analysis by means of three examples taken from civil engineering.

Design/methodology/approach

The first example refers to an arch bridge, the second one to the vault of a metro station and the third one to a real-scale test of a segmental tunnel ring.

Findings

The main conclusions drawn from these three examples are as follows: increasing the number of hangers/columns of the investigated arch bridge entails a reduction of the maximum bending moment of the arch, allowing it to approach, as much as possible, the desired thrust-line behavior; compared to the conventional in situ cast method, a combined precast and in situ cast method results in a decrease of the maximum bending moment of an element of the vault of the studied underground station by 46%; and the local behavior of the joints governs both the structural convergences and the bearing capacity of the tested segmental tunnel ring.

Originality/value

The three examples underline that the transfer relations significantly facilitate computer-aided engineering of circular arch structures, including arch bridges, vaults of metro stations and segmental tunnel rings.

Details

Engineering Computations, vol. 38 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 1 March 2001

K.G.B. Bakewell

Compiled by K.G.B. Bakewell covering the following journals published by MCB University Press: Facilities Volumes 8‐18; Journal of Property Investment & Finance Volumes…

Abstract

Compiled by K.G.B. Bakewell covering the following journals published by MCB University Press: Facilities Volumes 8‐18; Journal of Property Investment & Finance Volumes 8‐18; Property Management Volumes 8‐18; Structural Survey Volumes 8‐18.

Details

Structural Survey, vol. 19 no. 3
Type: Research Article
ISSN: 0263-080X

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Article
Publication date: 1 September 2001

Index by subjects, compiled by K.G.B. Bakewell covering the following journals: Facilities Volumes 8‐18; Journal of Property Investment & Finance Volumes 8‐18; Property…

Abstract

Index by subjects, compiled by K.G.B. Bakewell covering the following journals: Facilities Volumes 8‐18; Journal of Property Investment & Finance Volumes 8‐18; Property Management Volumes 8‐18; Structural Survey Volumes 8‐18.

Details

Facilities, vol. 19 no. 9
Type: Research Article
ISSN: 0263-2772

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Article
Publication date: 1 March 2001

K.G.B. Bakewell

Compiled by K.G.B. Bakewell covering the following journals published by MCB University Press: Facilities Volumes 8‐18; Journal of Property Investment & Finance Volumes…

Abstract

Compiled by K.G.B. Bakewell covering the following journals published by MCB University Press: Facilities Volumes 8‐18; Journal of Property Investment & Finance Volumes 8‐18; Property Management Volumes 8‐18; Structural Survey Volumes 8‐18.

Details

Property Management, vol. 19 no. 3
Type: Research Article
ISSN: 0263-7472

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Article
Publication date: 1 May 2001

K.G.B. Bakewell

Compiled by K.G.B. Bakewell covering the following journals published by MCB University Press: Facilities Volumes 8‐18; Journal of Property Investment & Finance Volumes…

Abstract

Compiled by K.G.B. Bakewell covering the following journals published by MCB University Press: Facilities Volumes 8‐18; Journal of Property Investment & Finance Volumes 8‐18; Property Management Volumes 8‐18; Structural Survey Volumes 8‐18.

Details

Journal of Property Investment & Finance, vol. 19 no. 5
Type: Research Article
ISSN: 1463-578X

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