• Title/Summary/Keyword: LU10

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Effect of soil-structure interaction on the reliability of hyperbolic cooling towers

  • Liao, Wen;Lu, Wenda;Liu, Renhuai
    • Structural Engineering and Mechanics
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    • v.7 no.2
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    • pp.217-224
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    • 1999
  • A semi-stochastic process model of reliability was established for hyperbolic cooling towers subjected to combined loadings of wind force, self-weight, temperature loading. Effect of the soil-structure interaction on reliability was evaluated. By involving the gust factor, an equivalent static scheme was employed to convert the dynamic model to static model. The TR combination rule was used to consider relations between load responses. An analysis example was made on the 90M cooling tower of Maoming, Guangdong of China. Numerical results show that the design not including interaction turns to be conservative.

Experimental study on the seismic behavior in the connection between CFRT column and steel beam

  • Lu, Xilin;Yu, Yong;Kiyoshi, Tanaka;Satoshi, Sasaki
    • Structural Engineering and Mechanics
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    • v.9 no.4
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    • pp.365-374
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    • 2000
  • The structural behavior of connections between concrete-filled rectangular tubular column (CFRT column) and steel beam has been studied in this paper through sub-assemblage loading tests. It is found that the sub-assemblages exhibit ductile restoring force characteristics under seismic loading. A formula for the prediction of the yield strength of each member in the connection is proposed by using the yield line theory under the assumption of a simple stress transfer mechanism. It is shown that the proposed formula can produce a reasonable prediction while providing a basis for further investigation.

Numerical study of dynamic buckling for plate and shell structures

  • Liu, Z.S.;Lee, H.P.;Lu, C.
    • Structural Engineering and Mechanics
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    • v.20 no.2
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    • pp.241-257
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    • 2005
  • A numerical approach combining the finite element method with two different stability criteria namely the Budiansky and the phase-plane buckling criteria is used to study the dynamic buckling phenomena of plate and shell structures subjected to sudden applied loading. In the finite element analysis an explicit time integration scheme is used and the two criteria are implemented in the Finite Element analysis. The dynamic responses of the plate and shell structures have been investigated for different values of the plate and shell imperfection factors. The results indicate that the dynamic buckling time, which is normally considered in predicting elasto-plastic buckling behavior, should be taken into consideration with the buckling criteria for elastic buckling analysis of plate and shell structures. By selecting proper control variables and incorporating them with two dynamic buckling criteria, the unique dynamic buckling load can be obtained and the problems of ambiguity and contradiction of dynamic buckling load of plate and shell structure can be resolved.

Mode localization and frequency loci veering in a disordered coupled beam system

  • Lu, Z.R.;Liu, J.K.;Huang, M.
    • Structural Engineering and Mechanics
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    • v.24 no.4
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    • pp.493-508
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    • 2006
  • Vibration mode localization and frequency loci veering in disordered coupled beam system are studied in this paper using finite element analysis. Two beams coupled with transverse and rotational springs are examined. Small disorders in the physical parameters such as Young's modulus, mass density or span length of the substructure are introduced in the investigation of the mode localization and frequency loci veering phenomena. The effect of disorder in the elastic support on the mode localization phenomenon is also discussed. It is found that an asymmetric disorder in the weakly coupled system will lead to the occurrence of mode localization and frequency loci phenomena.

Applications of fiber optic sensors in civil engineering

  • Deng, Lu;Cai, C.S.
    • Structural Engineering and Mechanics
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    • v.25 no.5
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    • pp.577-596
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    • 2007
  • Recent development of fiber optic sensor technology has provided an excellent choice for civil engineers for performance monitoring of civil infrastructures. Fiber optic sensors have the advantages of small dimensions, good resolution and accuracy, as well as excellent ability to transmit signal at long distances. They are also immune to electromagnetic and radio frequency interference and may incorporate a series of interrogated sensors multiplexed along a single fiber. These advantages make fiber optic sensors a better method than traditional damage detection methods and devices to some extent. This paper provides a review of recent developments in fiber optic sensor technology as well as some applications of fiber optic sensors to the performance monitoring of civil infrastructures such as buildings, bridges, pavements, dams, pipelines, tunnels, piles, etc. Existing problems of fiber optic sensors with their applications to civil structural performance monitoring are also discussed.

Research on rib-to-diaphragm welded connection by means of hot spot stress approach

  • Wang, Binhua;Lu, Pengmin;Shao, Yuhong
    • Steel and Composite Structures
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    • v.18 no.1
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    • pp.135-148
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    • 2015
  • The cutout hole locating at the place of rib-to-diaphragm welded connection is adopted to minimize the restraint, which is caused by the floor-beam web to rib rotation at the support due to the unsymmetrical loads in orthotropic deck. In practice, an inevitable problem is that there is a large number of welding joint's cracks formed at the edge of cutout hole. In this study, a comparative experiment is carried out with two types of cutout hole, the circular arc transition and the vertical transition. The fatigue life estimation of specimens is investigated with the application of the structural hot spot stress approach by finite element analyses. The results are compared with the ones of the fatigue tests which are carried out on these full-scale specimens. Factors affecting the stress range are also studied.

Complex Regulatory Network of MicroRNAs, Transcription Factors, Gene Alterations in Adrenocortical Cancer

  • Zhang, Bo;Xu, Zhi-Wen;Wang, Kun-Hao;Lu, Tian-Cheng;Du, Ye
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.4
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    • pp.2265-2268
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    • 2013
  • Several lines of evidence indicate that cancer is a multistep process. To survey the mechanisms involving gene alteration and miRNAs in adrenocortical cancer, we focused on transcriptional factors as a point of penetration to build a regulatory network. We derived three level networks: differentially expressed; related; and global. A topology network ws then set up for development of adrenocortical cancer. In this network, we found that some pathways with differentially expressed elements (genetic and miRNA) showed some self-adaption relations, such as EGFR. The differentially expressed elements partially uncovered mechanistic changes for adrenocortical cancer which should guide medical researchers to further achieve pertinent research.

A Review on Yard Management in Container Terminals

  • Zhen, Lu;Jiang, Xinjia;Lee, Loo Hay;Chew, Ek Peng
    • Industrial Engineering and Management Systems
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    • v.12 no.4
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    • pp.289-304
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    • 2013
  • With advancements of quay side equipments and technologies, the bottleneck of port operations has moved from quay side to yard side. The yard management of a port has significant influences on the competitiveness of a port in the global shipping network. The research area of yard management has attracted a lot of attentions from both the academia and the industrial practitioners. This paper gives a comprehensive review for the studies on the yard management in container terminals. From three aspects, i.e., yard cranes management, yard vehicles management, and yard spaces management, this paper reports the advances in these three areas. Some future directions on the yard management researches are also discussed. The purpose of this paper is to stimulate more practically relevant researches in this emerging area.

Social Incentives for Cooperative Spectrum Sensing in Distributed Cognitive Radio Networks

  • Feng, Jingyu;Lu, Guangyue;Min, Xiangcen
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.2
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    • pp.355-370
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    • 2014
  • Cooperative spectrum sensing has been considered as a promising approach to improve the sensing performance in distributed cognitive radio networks. However, there may exist some selfish secondary users (SUs) who are unwilling to cooperate. The presence of selfish SUs could cause catastrophic damage to the performance of cooperative spectrum sensing. Following the social perspective, we propose a Social Tie-based Incentive Scheme (STIS) to deal with the selfish problem for cooperative spectrum sensing in distributed cognitive radio networks. This scheme inspires SUs to contribute sensing information for the SUs who have social tie but not others, and such willingness varies with the strength of social tie value. The evaluation of each SU's social tie derives from its contribution for others. Finally, simulation results validate the effectiveness of the proposed scheme.

Sensorless Control for Surface Mounted Permanent Magnet Synchronous Machines at Low Speed

  • An, Lu;Franck, David;Hameyer, Kay
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.4
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    • pp.429-435
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    • 2013
  • This paper proposes a sensorless speed control based on a novel extension of the torque producing flux (active flux) observer for the surface mounted permanent magnet synchronous machines (SPMSM) without additional high frequency signal injection. From the estimated torque producing flux, the rotor position and speed can be calculated at low speed due to their independency. Therefore, no rotor position sensor is required. Two approaches of the torque producing flux observer are presented and compared. The results show the stability and robustness of the expansion of the torque producing flux observer at low speed for the SPMSM.