Bijuan Yan, Huijun Liang, Minjie Jin, Zhanlong Li and Yong Song
In the vibration reduction field, constrained stand-off layer damping cylindrical shell plays an important role. However, due to the lack of accurate analysis of its damping…
Abstract
Purpose
In the vibration reduction field, constrained stand-off layer damping cylindrical shell plays an important role. However, due to the lack of accurate analysis of its damping characteristics, this hinders its further research and application. Therefore, the purpose of this paper is concerned with an accurate solution for the vibration-damping characteristics of a constrained stand-off-layer damping cylindrical shell (CSDCS) under various classical boundary conditions and conducts a further analysis.
Design/methodology/approach
Based on the Rayleigh–Ritz method and the Hamilton principle, a dynamic model of CSDCS is established. Then the loss factor and the frequency of CSDCS are obtained. The correctness and convergence behavior of the present model are verified by comparing the calculation results with the literature. By using for various classical boundary conditions without any special modifications in the solution procedure, the characteristics of CSDCS with S-S, C-C, C-S, C-F and S-F boundaries are discussed.
Findings
The Rayleigh–Ritz method is effective in handling the problem of CSDCS with different boundaries and an accurate solution is obtained. The boundary conditions have an important influence on the vibration and damping behavior of the CSDCS.
Originality/value
Based on the Rayleigh–Ritz method and Hamilton principle, a dynamic model of CSDCS is established for the first time, and then the loss factor and frequency of CSDCS are obtained. In addition, the effectiveness of adding the stand-off layer between the base shell and the viscoelastic layer is confirmed by discussing the characteristics of CSDCS with S-S, C-C, C-S, C-F and S-F boundaries.
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Yan Ning, Minjie Feng, Jin Feng and Xiao Liu
Drawing upon the ambivalence literature, the purpose of this paper is to explore clients’ ambivalence caused by the co-existence of trust and distrust and to investigate how…
Abstract
Purpose
Drawing upon the ambivalence literature, the purpose of this paper is to explore clients’ ambivalence caused by the co-existence of trust and distrust and to investigate how clients respond to the ambivalence.
Design/methodology/approach
Qualitative research strategies using multiple data sources were adopted. Face-to-face interviews were the major method for gathering data. Additional data sources included archival cases, official reports, regulations and rules and survey reports.
Findings
The results identified that clients’ ambivalence occurs in the face of the co-existence of trust and distrust. Clients might trust contractors on certain aspects and distrust of others or when they realize that trust and/or distrust have mixed merits and demerits. As a response strategy to the ambivalence, clients may choose to oscillate between trust and distrust in accordance with contractors’ quality and cost performance.
Research limitations/implications
One limitation is that dwelling fit-out projects are generally small in size. Parties in small size projects might have different mindsets than large projects. Thus, it is worthwhile to extend the framework to the context of large projects.
Practical implications
Managers or clients should be aware of the double-edged sword nature of trust and distrust. To deal with the ambivalence resulting from co-existence of trust and distrust, a proper balance of trust and distrust might be effective.
Originality/value
This study contributes an ambivalence approach to the trust research in project management.
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Kun Sun, Dichen Li, Haihua Wu, Minjie Wang and Xiaoyong Tian
The purpose of this paper is to bring up the concept of multi‐material electromagnetic band‐gap structure (EBGs) and develop a method for its fabrication. Meanwhile, its microwave…
Abstract
Purpose
The purpose of this paper is to bring up the concept of multi‐material electromagnetic band‐gap structure (EBGs) and develop a method for its fabrication. Meanwhile, its microwave properties were studied and compared with the traditional EBGs consisting of two kinds of material.
Design/methodology/approach
Stereolithography (SL) and gel casting were used to fabricate 3D multi‐material EBGs. Resin mold was designed and fabricated based on SL process, slurries loaded with 55vol per cent Al2O3 and 55vol per cent TiO2, respectively, were prepared, and using gel casting, multilayer EBGs with diamond structure were fabricated. T/R method was used to obtain the characteristic parameter S21 of the EBGs; meanwhile, characters of their band structure were studied based on plane wave expansion method.
Findings
The fabricated EBGs with a TiO2‐resin‐air structure showed a band gap from 11.7 GHz to 16.0 GHz along <1, 1, 0> direction; the EBGs with a TiO2‐resin‐Al2O3 structure showed a band gap from 11.4 GHz to 11.9 GHz along <1, 1, 0> direction. Both of them agreed well with the simulation result. Also, through the study of multi‐material EBGs' microwave properties, it could be seen that this structure was a good approach to adjust the band gap.
Originality/value
With the concept of multi‐material EBG structure brought up, multilayer 3D EBGs were designed and fabricated based on SL combined with gel casting. It could be seen that multi‐material EBGs was a good approach to adjust the band gap. Also, the fact that the testing result matched the simulation validates the feasibility of the process.
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Zheyu Li, Muhammad Najib Razali, Hassan Gholipour Fereidouni and Yasmin Mohd. Adnan
The purpose of this study is to estimate different data models on house prices using statistical models and the variables which are controlled by real estate policy.
Abstract
Purpose
The purpose of this study is to estimate different data models on house prices using statistical models and the variables which are controlled by real estate policy.
Design/methodology/approach
This study used several statistical techniques, such as Vector auto-regression (VAR), Johansen co-integration and variance decomposition, which aim to assess the significant effect of macroeconomic factors on Chinese house prices.
Findings
The results show that land supply and other variables have negative effects on house prices. The results also indicate that financial mortgages for real estate have positive effects on house prices and the area of vacant houses as well as the area of housing sold.
Research limitations/implications
This study only covers three cities in China because of limitations of data for other cities.
Originality/value
This study proposes policy suggestions according to the empirical results obtained.
Hua Du, Qi Han, Jun Sun and Cynthia Changxin Wang
This study aims to evaluate the effectiveness of different prefabricated construction (PC) policies using a case study in Wuhan, considering the local context.
Abstract
Purpose
This study aims to evaluate the effectiveness of different prefabricated construction (PC) policies using a case study in Wuhan, considering the local context.
Design/methodology/approach
The effectiveness of PC policies is falling behind expectations. The main reason lies in an insufficient understanding of the policy impacts. An agent-based model was built by choosing the residential sector in a typical large city of Wuhan, China, as the study case. Different cost reduction scenarios were introduced for investigating the PC policy effectiveness. The proposed model and simulation approach can be used for other cities and generalized to the whole Chinese PC industry with the potential to include more local policies and corresponding data.
Findings
Simulation results show that carbon emission reduction will be between 60,000 and 80,000 tons with policy incentives, nearly double that of the no policy intervention scenario. The target of 30% PC in all new buildings by 2026 in China is achievable with the subsidy policies of linear cost reduction, or cost reduction conforms to the learning curve.
Practical implications
Simulation results of three kinds of policy show that subsidy policy optimization is necessary regarding reducing the level of subsidy needed. The carbon credit policy is not essential since it has little influence on PC development. Implementing the project procurement restriction policy is not recommended if the scale of development of PC is more important than achieving the development target.
Originality/value
This study can help the government and developers make better policy and strategic decisions on PC development and boost the sustainability transition of the construction industry.