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Article
Publication date: 1 March 1990

A.E. Kanarachos, N. Koutsidis and C.N. Spentzas

We present a combined or mixed method for the dynamic analysis of thin‐walled structures, based on the superposition of beam and shell strains and displacements…

Abstract

We present a combined or mixed method for the dynamic analysis of thin‐walled structures, based on the superposition of beam and shell strains and displacements. Polynomial or exact shape functions are used for the interpolation of the shell displacements, while discrete degrees of freedom are introduced instead of the generalized von Karman coefficients. Special attention has been given to the integration schemes, because of the combined beam and shell behaviour of the considered structures. The stability and accuracy of the four‐point integration scheme are studied by using the z‐transform. The method is applied to thin‐walled pipes and is also compared to the von Karman approach.

Details

Engineering Computations, vol. 7 no. 3
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 February 1993

A.E. KANARACHOS and I.P. VOURNAS

An optimized multigrid method (NSFLEX‐MG) for the NSFLEX‐code (Navier‐Stokes solver using characteristic flux extrapolation) of MBB (Messerschmitt Bolkow Blohm GmbH) is…

Abstract

An optimized multigrid method (NSFLEX‐MG) for the NSFLEX‐code (Navier‐Stokes solver using characteristic flux extrapolation) of MBB (Messerschmitt Bolkow Blohm GmbH) is described. The method is based on a correction scheme and implicit relaxation procedures and is applied to two‐dimensional test cases. The principal feature of the flow solver is a Godunov‐type averaging procedure based on the eigenvalues analysis of the Euler equations by means of which the inviscid fluxes are evaluated at the finite volume faces. Viscous fluxes are centrally differenced at each cell face. The performance of NSFLEX‐MG is demonstrated for a large range of Mach numbers for compressible inviscid and viscous (laminar and turbulent) flows over a RAE‐2822 airfoil and over a NACA‐0012 airfoil.

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Engineering Computations, vol. 10 no. 2
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 January 1988

A.E. Kanarachos and C.N. Spentzas

Considering typical self‐adjoint and non‐self‐adjoint problems that are governed by differential equations with predominant lower order derivatives, a comparison is…

Abstract

Considering typical self‐adjoint and non‐self‐adjoint problems that are governed by differential equations with predominant lower order derivatives, a comparison is presented of their finite element solutions by Ritz, Galerkin, least square (LSQ) and discrete least square (DLSQ) methods.

Details

Engineering Computations, vol. 5 no. 1
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 May 1994

I. Antoniadis and A. Kanarachos

Although the existence of a close relationship between the areas ofdigital signal processing and time integration methodology is known, asystematic application of the…

Abstract

Although the existence of a close relationship between the areas of digital signal processing and time integration methodology is known, a systematic application of the concepts and methods of the first area to the second is missing. Such an approach is followed in this paper, arising from the fact that any time integration formula can be viewed as a digital filter of the applied excitation force, approximating as close as possible to the behaviour of a ‘prototype analogue filter’, which is in fact the semi discrete equations of motion of the system. This approach provides a universal framework for handling and analysing all various aspects of time integration formulae, such as analysis in the frequency domain, algebraic operations, accuracy and stability, aliasing, spurious oscillations generation, introduction of digital filters within the time integration formula, initial conditions handling and overshooting. Additionally it is shown that digital signal processing methods, such as pre‐ or post‐processing, time delays, etc. can be in certain cases a quite effective complement of the time integration scheme.

Details

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

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Article
Publication date: 7 April 2020

Theodoros Anagnostopoulos, Chu Luo, Jino Ramson, Klimis Ntalianis, Vassilis Kostakos and Christos Skourlas

The purpose of this paper is to propose a distributed smartphone sensing-enabled system, which assumes an intelligent transport signaling (ITS) infrastructure that…

Abstract

Purpose

The purpose of this paper is to propose a distributed smartphone sensing-enabled system, which assumes an intelligent transport signaling (ITS) infrastructure that operates traffic lights in a smart city (SC). The system is able to handle priorities between groups of cyclists (crowd-cycling) and traffic when approaching traffic lights at road junctions.

Design/methodology/approach

The system takes into consideration normal probability density function (PDF) and analytics computed for a certain group of cyclists (i.e. crowd-cycling). An inference model is built based on real-time spatiotemporal data of the cyclists. As the system is highly distributed – both physically (i.e. location of the cyclists) and logically (i.e. different threads), the problem is treated under the umbrella of multi-agent systems (MAS) modeling. The proposed model is experimentally evaluated by incorporating a real GPS trace data set from the SC of Melbourne, Australia. The MAS model is applied to the data set according to the quantitative and qualitative criteria adopted. Cyclists’ satisfaction (CS) is defined as a function, which measures the satisfaction of the cyclists. This is the case where the cyclists wait the least amount of time at traffic lights and move as fast as they can toward their destination. ITS system satisfaction (SS) is defined as a function that measures the satisfaction of the ITS system. This is the case where the system serves the maximum number of cyclists with the fewest transitions between the lights. Smart city satisfaction (SCS) is defined as a function that measures the overall satisfaction of the cyclists and the ITS system in the SC based on CS and SS. SCS defines three SC policies (SCP), namely, CS is maximum and SS is minimum then the SC is cyclist-friendly (SCP1), CS is average and SS is average then the SC is equally cyclist and ITS system friendly (SCP2) and CS is minimum and SS is maximum then the SC is ITS system friendly (SCP3).

Findings

Results are promising toward the integration of the proposed system with contemporary SCs, as the stakeholders are able to choose between the proposed SCPs according to the SC infrastructure. More specifically, cyclist-friendly SCs can adopt SCP1, SCs that treat cyclists and ITS equally can adopt SCP2 and ITS friendly SCs can adopt SCP3.

Originality/value

The proposed approach uses internet connectivity available in modern smartphones, which provide users control over the data they provide to us, to obviate the installation of additional sensing infrastructure. It extends related study by assuming an ITS system, which turns traffic lights green by considering the normal PDF and the analytics computed for a certain group of cyclists. The inference model is built based on the real-time spatiotemporal data of the cyclists. As the system is highly distributed – both physically (i.e. location of the cyclists) and logically (i.e. different threads), the system is treated under the umbrella of MAS. MAS has been used in the literature to model complex systems by incorporating intelligent agents. In this study, the authors treat agents as proxy threads running in the cloud, as they require high computation power not available to smartphones.

Details

Journal of Systems and Information Technology, vol. 22 no. 1
Type: Research Article
ISSN: 1328-7265

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Article
Publication date: 23 December 2019

Maciel M. Queiroz, Susana Carla Farias Pereira, Renato Telles and Marcio C. Machado

The Industry 4.0 phenomenon is bringing unprecedented disruptions for all traditional business models and hastening the need for a redesign and digitisation of activities…

Abstract

Purpose

The Industry 4.0 phenomenon is bringing unprecedented disruptions for all traditional business models and hastening the need for a redesign and digitisation of activities. In this context, the literature concerning the digital supply chain (DSC) and its capabilities are in the early stages. To bridge this gap, the purpose of this paper is to propose a framework for digital supply chain capabilities (DSCCs).

Design/methodology/approach

This paper uses a narrative literature approach, based on the main Industry 4.0 elements, supply chain and the emerging literature concerning DSC disruptions, to build an integrative framework to shed light on DSCCs.

Findings

The study identifies seven basic capabilities that shape the DSCC framework and six main enabler technologies, derived from 13 propositions.

Research limitations/implications

The proposed framework can bring valuable insights for future research development, although it has not been tested yet.

Practical implications

Managers, practitioners and all involved in the digitalisation phenomenon can utilise the framework as a starting point for other business digitalisation projects.

Originality/value

This study contributes to advancing the DSC literature, providing a well-articulated discussion and a framework regarding the capabilities, as well as 13 propositions that can generate valuable insights for other studies.

Details

Benchmarking: An International Journal, vol. 28 no. 5
Type: Research Article
ISSN: 1463-5771

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Article
Publication date: 4 July 2016

Herbert Martins Gomes

The purpose of this paper is to investigate the optimum design of a quarter car passive suspension system using a particle swarm optimization algorithm in order to…

Abstract

Purpose

The purpose of this paper is to investigate the optimum design of a quarter car passive suspension system using a particle swarm optimization algorithm in order to minimize the applied loads and vibrations.

Design/methodology/approach

The road excitation is assumed as zero-mean random field and modeled by single-sided power spectral density (PSD) based on international standard ISO 8608. The variance of sprung mass displacements and variance of dynamic applied load are evaluated by PSD functions and used as cost function for the optimization.

Findings

The advantages in using this methodology are emphasized by an example of the multi-objective optimization design of suspension parameters and the results are compared with values reported in the literature and other gradient based and heuristic algorithms. The paper shows that the algorithm effectively leads to reliable results for suspension parameters with low computational effort.

Research limitations/implications

The procedure is applied to a quarter car passive suspension design.

Practical implications

The proposed procedure implies substantial time savings due to frequency domain analysis.

Social implications

The paper proposes a procedure that allows complex optimization designs to be feasible and cost effective.

Originality/value

The design optimization is performed in the frequency domain taking into account standard defined road profiles PSD without the need to simulate in the time domain.

Details

Engineering Computations, vol. 33 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 12 March 2018

Yang Li, Zhaojun Yang, Fei Chen and Jin Zhao

This paper aims to investigate the effects of air inlet flow rate on the bearing cavity and operating conditions during the oil-air lubrication.

Abstract

Purpose

This paper aims to investigate the effects of air inlet flow rate on the bearing cavity and operating conditions during the oil-air lubrication.

Design/methodology/approach

A model of oil-air lubrication of rolling bearings is established using computational fluid dynamics numerical simulation. Moreover, temperature and vibration experiments are carried out for comparisons and validation.

Findings

Results suggest that the velocity and pressure distributions of the oil-air flow inside the chamber are not uniform. Moreover, the uniform decreases with increasing air inlet flow rate. The non-uniform oil distribution inside the bearing significantly influences the bearing temperature rise and lubrication effect. Furthermore, the decrease in pressure uniformity enhances the vibration intensity and increases the amplitude of the vibration acceleration by more than 40 per cent. Increasing the air inlet flow rate improves lubrication and cooling efficiency but produces intense vibrations.

Originality/value

A method of establishing rolling bearings model under oil-air lubrication is presented in the paper. The effect of air inlet flow rate on flow uniform under oil-air lubrication has been researched insightfully. The results provide a useful reference to improve the oil-air lubrication system and enhance the operational stability of the motorized spindle.

Details

Industrial Lubrication and Tribology, vol. 70 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

Content available
Article
Publication date: 2 May 2019

Minyoung Kwon, Hilde Remøy and Andy Van Den Dobbelsteen

This paper highlights the importance of user satisfaction in office renovation. A user-focussed renovation approach can enhance user satisfaction in offices and their…

Abstract

Purpose

This paper highlights the importance of user satisfaction in office renovation. A user-focussed renovation approach can enhance user satisfaction in offices and their functional quality while meeting energy performance goals. The purpose of this paper is to investigate users’ needs and the physical and psychological factors affecting user satisfaction, as input to office renovation projects.

Design/methodology/approach

The selected articles are collected from Scopus, ScienceDirect and Google Scholar. Searching was limited to the main key terms of office, work environment, and user satisfaction and comfort. The important factors were searched through empirical-based international literature mainly. Based hereupon, a guide will be developed for the analysis and evaluation of user satisfaction in office renovations.

Findings

From a comprehensive overview, the findings present ten main factors to increase user satisfaction in office renovation. These are associated with physical and psychological satisfaction and comfort. In addition, the influential factors were categorised into three levels based on needs theories to organise the hierarchy of priorities.

Practical implications

This research adds to the body of knowledge about which factors are important for user satisfaction, based on what previous research has found in that field. This is important to improve the sustainability in use.

Originality/value

User satisfaction is often studied through separate aspects: health and indoor climate vs functionality and productivity. This paper examines overall user satisfaction of workplaces by integrating the perspectives of physical and psychological conditions, and by providing insight into the priority of satisfaction factors.

Details

Property Management, vol. 37 no. 4
Type: Research Article
ISSN: 0263-7472

Keywords

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