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Article
Publication date: 7 August 2018

Smita Parida and Sukesh Chandra Mohanty

The purpose of this paper is to investigate the linear and non-linear free vibration of a functionally graded material (FGM) rotating cantilever plate in the thermal environment…

170

Abstract

Purpose

The purpose of this paper is to investigate the linear and non-linear free vibration of a functionally graded material (FGM) rotating cantilever plate in the thermal environment. The study employs the development of a non-linear mathematical model using the higher order shear deformation theory in which the traction free condition is applied to derive the simplified displacement model with seven field variables instead of nine.

Design/methodology/approach

A mathematical model is developed based on the higher order shear deformation theory using von-Karman type non-linearity. The rotating plate domain has been discretized into C0 eight-noded quadratic serendipity elements with node wise 7 degrees of freedom. The material properties are considered temperature dependent and graded along the thickness direction obeying a simple power law distribution in terms of the volume fraction of constituents, based on Voigt’s micromechanical method. The governing equations are derived using Hamilton’s principle and are solved using the direct iterative method.

Findings

The importance of the present mathematical model developed for numerical analysis has been stated through the comparison studies. The results provide an insight into the vibration response of FGM rotating plate under thermal environment. The influence of various parameters like setting angle, volume fraction index, hub radius, rotation speed parameter, aspect ratio, side-thickness ratio and temperature gradient on linear and non-linear frequency parameters is discussed in detail.

Originality/value

A non-linear mathematical model is newly developed based on C0 continuity for the functionally graded rotating plate considering the 1D Fourier equation of heat conduction. The present findings can be utilized for the design of rotating plates made up of a FGM in the thermal environment under real-life situations.

Details

Multidiscipline Modeling in Materials and Structures, vol. 15 no. 1
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 17 November 2021

Yudan Dou, Xiliang Sun, Ankang Ji, Yuna Wang and Xiaolong Xue

Owing to multiple superiorities to traditional counterparts, prefabricated construction (PC) has gained increasing attention worldwide. The development of PC projects reflects the…

709

Abstract

Purpose

Owing to multiple superiorities to traditional counterparts, prefabricated construction (PC) has gained increasing attention worldwide. The development of PC projects reflects the effects of both policy supervision and PC practice, which aids the government in reasonably identifying the key issues of PC's promotion and rationally improving the policy deployment. However, existing studies fail to address this aspect, especially lacking quantitative exploration. This study explores the micro mechanism of PC's promotion, from the perspective of developing PC projects.

Design/methodology/approach

A tripartite evolutionary game model based on prospect theory of the government, developers and contractors is constructed. After rigorous theoretical deduction, this study adopts Changchun in China as a case city and collects the data using the Delphi technique, policy documents and literature analysis.

Findings

Results indicate that contractors are generally willing to implement PC projects and the government chooses to actively supervise PC's promotion. The negative investment behavior of developers is the main obstacle to promote PC in Changchun currently.

Practical implications

The conclusions are applicable to other comparable regions. This study is of value to promote PC with high efficiency and effect.

Originality/value

The tripartite evolutionary game model based on prospect theory proposed in this study is conducive to reveal the essence of PC's promotion. This is an important breakthrough in extant studies, with a broad applicability in the PC domain beyond China.

Details

Engineering, Construction and Architectural Management, vol. 30 no. 1
Type: Research Article
ISSN: 0969-9988

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Article
Publication date: 2 February 2023

Xiang Shen, Eldad Avital, Zaheer Ikram, Liming Yang, Theodosios Korakianitis and Laurent Dala

This paper aims to investigate the influence of smooth curvature distributions on the self-noise of a low Reynolds number aerofoil and to unveil the flow mechanisms in the…

83

Abstract

Purpose

This paper aims to investigate the influence of smooth curvature distributions on the self-noise of a low Reynolds number aerofoil and to unveil the flow mechanisms in the phenomenon.

Design/methodology/approach

In this paper, large Eddy simulation (LES) approach was performed to investigate the unsteady aerodynamic performance of both the original aerofoil E387 and the redesigned aerofoil A7 in a time-dependent study of boundary layer characteristics at Reynolds number 100,000 and angle of attack (AoA) 4-degree. The aerofoil A7 is redesigned from E387 by removing the irregularities in the surface curvature distributions and keeping a nearly identical geometry. Flow vorticity magnitude of both aerofoils, along with the spectra of the vertical fluctuating velocity component and noise level, are analysed to demonstrate the bubble flapping process near the trailing edge (TE) and the vortex shedding phenomenon.

Findings

This paper provides quantitative insights about how the flapping process of the laminar separation bubble (LSB) within the boundary layer near the TE affects the aerofoil self-noise. It is found that the aerofoil A7 with smooth curvature distributions presents a 10% smaller LSB compared to the aerofoil E387 at Reynolds number 100,000 and AoA 4-degree. The LES results also suggest that curvature distribution smoothing leads to a 6.5% reduction in overall broadband noise level.

Originality/value

This paper fulfils an identified need to reveal the unknown flow structure and the boundary layer characteristics that resulted in the self-noise reduction phenomenon yielded by curvature distribution smoothing.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 33 no. 4
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 18 May 2020

Zhiyu Ni, Yewei Zhang, Xinhui Shen, Shunan Wu and Zhigang Wu

When a manipulator captures an unknown space object, inertia parameters of endpoint payload should be timely obtained to handle possible unexpected parameter variations and…

208

Abstract

Purpose

When a manipulator captures an unknown space object, inertia parameters of endpoint payload should be timely obtained to handle possible unexpected parameter variations and monitor the system’s operating conditions. Therefore, this study aims to present an identification method for estimating the inertia parameter of the payload carried by a flexible two-link space manipulator.

Design/methodology/approach

The original nonlinear dynamics model of the manipulator is linearized at a selected working point. Subsequently, the system modal frequencies with and without payload are determined using the subspace identification algorithm, and the difference of these frequencies is computed. Furthermore, by adjusting the structural configuration of the manipulator, multiple sets of frequency differences are obtained. Therefore, the inertia parameters of the payload, i.e. the mass and the moment of inertia, can be derived from the frequency differences by solving a least-squares problem.

Findings

The proposed method can effectively estimate the payload parameters and has satisfactory identification accuracy.

Practical implications

The approach’s implementation provides a practical reference for determining inertia parameters of an unknown space target in the capture process.

Originality/value

The study proposes a novel method for identifying the inertia parameters of the payload of a flexible two-link space manipulator using the estimated system frequencies.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 6
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 14 June 2024

Jie Wu, Kang Wang, Ming Zhang, Leilei Guo, Yongpeng Shen, Mingjie Wang, Jitao Zhang and Vaclav Snasel

When solving the cogging torque of complex electromagnetic structures, such as consequent pole hybrid excitation synchronous (CPHES) machine, traditional methods have a huge…

58

Abstract

Purpose

When solving the cogging torque of complex electromagnetic structures, such as consequent pole hybrid excitation synchronous (CPHES) machine, traditional methods have a huge computational complexity. The notable feature of CPHES machine is the symmetric range of field-strengthening and field-weakening, but this type of machine is destined to be equipped with a complex electromagnetic structure. The purpose of this paper is to propose a hybrid analysis method to quickly and accurately solve the cogging torque of complex 3D electromagnetic structure, which is applicable to CPHES machine with different magnetic pole shapings.

Design/methodology/approach

In this paper, a hybrid method for calculating the cogging torque of CPHES machine is proposed, which considers three commonly used pole shapings. Firstly, through magnetic field analysis, the complex 3D finite element analysis (FEA) is simplified to 2D field computing. Secondly, the discretization method is used to obtain the distribution of permeance and permeance differential along the circumference of the air-gap, taking into account the effect of slots. Finally, the cogging torque of the whole motor is obtained by using the idea of modular calculation and the symmetry of the rotor structure.

Findings

This method is applicable to different pole shapings. The experimental results show that the proposed method is consistent with 3D FEA and experimental measured results, and the average calculation time is reduced from 8 h to 4 min.

Originality/value

This paper proposes a new concept for calculating cogging torque, which is a hybrid calculation of dimension reduction and discretization modules. Based on magnetic field analysis, the 3D problem is simplified into a 2D issue, reducing computational complexity. Based on the symmetry of the machine structure, a modeling method for discretized analytical models is proposed to calculate the cogging torque of the machine.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 43 no. 5
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 24 August 2010

Xiaoling Zhang, Liyin Shen, Yuzhe Wu and Yi Peng

The objective of this paper is to find an effective approach for enabling real estate firms to understand their competitiveness and identify the core competitiveness indicators…

2239

Abstract

Purpose

The objective of this paper is to find an effective approach for enabling real estate firms to understand their competitiveness and identify the core competitiveness indicators (CCIs) that influence the development of developers with particular reference to the Chinese real estate business environment.

Design/methodology/approach

A combined method including Monte Carlo simulation (MCS) and the fuzzy set method was used to identify CCIs. Research data used for analysis were collected from a questionnaire survey in the Chinese real estate industry.

Findings

Analysis results suggest core indicators for assessing real estate developers' competitiveness include: good corporate brand awareness and sufficient resources for expansion, have access to a diverse range of capital, appropriate annual land reserve, excellent entrepreneurship, proper risk assessment and response capacity, and green development strategy.

Practical implications

The examination of the CCIs furnishes real estate firms with core indicators to assess their competitiveness, thus adopt appropriate strategies to enhance their competitiveness in the real estate market. The findings offer new insights and references for studying similar topics in other industries and countries.

Originality/value

The paper chooses an effective approach to identify the competitiveness indicators for real estate firms by using a combined method including MCS and the fuzzy set method.

Details

Facilities, vol. 28 no. 11/12
Type: Research Article
ISSN: 0263-2772

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Article
Publication date: 18 August 2021

Ibrahim Yahaya Wuni, Geoffrey Qiping Shen and Amos Darko

Industrialized construction (IC) leverages manufacturing principles and innovative processes to improve the performance of construction projects. Though IC is gaining popularity…

664

Abstract

Purpose

Industrialized construction (IC) leverages manufacturing principles and innovative processes to improve the performance of construction projects. Though IC is gaining popularity in the global construction industry, studies that establish the best practices for implementing IC projects are scarce. This study aims to benchmark practical lifecycle-based best practices for implementing IC projects.

Design/methodology/approach

The study used a qualitative research design where nine IC cases from Australia, Singapore and Hong Kong were analysed to identify best practices. The methodological framework of the study followed well-established case study research cycle and guidelines, including planning, data collection, data analysis and reflection on findings.

Findings

The study identified and allocated key considerations, relevant stakeholders, best practices, typical deliverables and best indicators to the different construction lifecycle phases of IC projects. It also developed a lifecycle-based framework of the best practices for IC projects.

Practical implications

The study provides practitioners with practical insight into how best to effectively implement, manage and evaluate the performance of the IC project lifecycle phases. The proposed framework can serve as a practical diagnostic tool that enables project partners to evaluate the performance upfront progressively and objectively in each project lifecycle phase, which may inform timely corrective actions.

Originality/value

The study’s novelty lies in developing a framework that identifies and demonstrates the dynamic linkages among different sets of best practices, typical outputs and best practice indicators across the IC project lifecycle phases.

Details

Construction Innovation , vol. 22 no. 4
Type: Research Article
ISSN: 1471-4175

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Article
Publication date: 1 January 2006

Aimin Jiang, Haojiang Ding and Guoquan Wu

Based on the governing equations of magneto‐electro‐elastic media, the general solutions in the case of distinct eigenvalues and is introduced and expressed in four harmonic…

86

Abstract

Based on the governing equations of magneto‐electro‐elastic media, the general solutions in the case of distinct eigenvalues and is introduced and expressed in four harmonic functions. Then, the Green’s functions for point forces, point charge and point current acting in the interior of a two‐phase infinite magneto‐electro‐elastic plane in the case of distinct or multiple eigenvalues are given using the method of mirror image source.

Details

Multidiscipline Modeling in Materials and Structures, vol. 2 no. 1
Type: Research Article
ISSN: 1573-6105

Keywords

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Book part
Publication date: 4 November 2024

Jules Yimga

Given that a prerequisite for COVID-19 transmission is the interaction between individuals, it is reasonable to suspect that transportation networks may have contributed to the…

Abstract

Given that a prerequisite for COVID-19 transmission is the interaction between individuals, it is reasonable to suspect that transportation networks may have contributed to the spread of COVID-19. This study uses the air transportation network to quantify the risk of COVID-19 spread in the United States. The proposed model is applied at the county level and identifies the risk of importing COVID-19-infected passengers into a given county. We also undertake an examination of the factors influencing the spread of COVID-19 in relation to air travel. Utilizing an extensive dataset encompassing various socioeconomic, demographic, and healthcare-related variables, our results indicate a positive relationship between these factors and the relative risk of COVID-19 spread, highlighting the pronounced impact of population density, air travel volume, and larger household sizes on increasing travel-related risk. Conversely, greater healthcare capacity, particularly in terms of hospital and intensive care unit (ICU) beds, is associated with reduced risk. We provide estimates of expected relative risk for each county and a ranking that can be useful for informing public health policies to stem the spread of the virus by devoting resources such as screening and enhanced travel protocols to airports located in at-risk counties.

Details

Airlines and the COVID-19 Pandemic
Type: Book
ISBN: 978-1-80455-505-7

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Article
Publication date: 6 April 2022

Sinan Maraş and Mustafa Yaman

This study aims to demonstrate the numerical application of differential quadrature (DQ) methods and show the experimental application of free vibration analysis of fiber-metal…

318

Abstract

Purpose

This study aims to demonstrate the numerical application of differential quadrature (DQ) methods and show the experimental application of free vibration analysis of fiber-metal laminated composite (FML) plates with various boundary conditions.

Design/methodology/approach

The FMLs are hybrid structures consisting of fiber-reinforced polymer matrix composites such as carbon, glass, aramid and different metal sheets, and are currently widely used in the automobile, aircraft and aerospace industries. Thus, free vibration analysis of these hybrid materials is necessary for the design process. The governing equations of motion are derived based on the classical plate theory. The DQ, generalized DQ (GDQ) and harmonic DQ (HDQ) differential quadrature methods have been used to solve the governing equations of an FML composite plate numerically. The accuracy and convergence of the numerical model have been verified by comparing the results available in the published literature with the results obtained from these methods. Moreover, an experimental procedure has been performed in order to compare the results against those of the numerical methods.

Findings

It is noteworthy that a high degree of similarity and accuracy was observed between the numerical results obtained by the DQ methods and the experimental results. Thus, the present study validates the applicability of the DQ methods for designing the FML composite plates.

Originality/value

In this study, the advantages of the DQ methods have been demonstrated differently from previous studies on the vibration analysis of the FML plates.

Details

Engineering Computations, vol. 39 no. 6
Type: Research Article
ISSN: 0264-4401

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