Huang J.-H.,Chongqing University |
Chen Z.-H.,Chongqing University |
Ma D.-S.,North China Power Engineering Company Ltd |
Li G.-Y.,Yunnan Electrical Power Design Institute
Gongcheng Lixue/Engineering Mechanics | Year: 2012
The elevated box girders would bear an additional large soil pressure and a vehicle load because of the backfilling of gulch and road construction caused by the function changes of urban lands. The change of a load case would result in the failure risk of a pipeline structure. The static properties of the reinforced concrete deep elevated box girders commonly used in the urban sewage pipeline system are experimentally analyzed. The failure pattern, shear lag effect and shear behavior of such deep box girders are studied. The shortages in the present design codes for the calculation of bending capacities of the box girders are also discussed. The box girder is simulated by using the non-linear finite element method. It is shown that under the vertical uniformly distributed load, the failure pattern of the simple-supported rectangular deep box girder with a depth-to-span ratio of nearly five is bending failure. The shear lag effect in the mid-span section is non-obvious, while it is more obvious before cracking in a quarter-span section. However, the lag effect is weakened gradually after cracking. The results simulated by the non-linear finite element method show an agreement with the experimental results. In order to avoid the premature cracking which affects the serviceability of a sewage pipeline, reinforcing measures should be carried out before the backfilling to the designed simple-supported sewage pipeline.
Zeng F.,Hunan University |
Tang Y.,Hunan University |
Pu J.,Yunnan Electrical Power Design Institute
The Scientific World Journal | Year: 2014
Considering the limited resources and the dynamic spectrum distribution in the cognitive radio sensor networks (CRSN), a half-duplex Multichannel broadcast protocol for CRSN is presented based on the home channel. This protocol maintains the networks topology only through the home channel, so there is no need for the public channel to transmit the control information and no need for the synchronization. After network initialization, node broadcasts data via home channel in half-duplex transmission way. The simulation results show that, compared with complete broadcast, the proposed protocol effectively reduces broadcast delay and overhead. © 2014 Fanzi Zeng et al.
Gao M.,Yunnan Electrical Power Dispatching Center |
Yuan L.,Yunnan Electrical Power Design Institute |
Li W.-Y.,Yunnan Electrical Power Dispatching Center |
Luo X.-L.,Yunnan Electrical Power Institute
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2011
Some key problems of power dispatching system information construction are discussed. The related research and application of the power dispatching comprehensive data platform is proposed to be promoted to the power dispatching system information. The relationship between the dispatching information and the intelligent dispatching is discussed, the construction mode of the dispatching information is discussed and advised, and the relationship between the dispatching information and the dispatching automation is determined. The dispatching business is summarized and divided, the application functions are mapped from them, the application systems framework is obtained according to the application functions, and some examples are given. The data structure of the dispatching system information is deduced, and an example of the transverse data stream analysis is given.
Wang Z.,University of Sichuan |
Tan L.,University of Sichuan |
Tan L.,Yunnan Electrical Power Design Institute |
Wang Q.,University of Sichuan
International Journal of Steel Structures | Year: 2013
Fatigue strength evaluation of welded structural details is of practical significance in the design of corrugated steel web girders in highway bridges and industrial structures. In this paper, the fatigue strengths of corrugated steel web girders with several welded structural details and welding methods are analytically examined by fatigue tests of corrugated web beams and small-size welded joints. The stress concentration & distribution characteristics of corrugated web beams were analysed using finite element analysis. The beam test results showed that the structure with scallops or notches in the flange has lower fatigue strength and that with butt joints is prone to suffer from shear crack on the corrugated web. Within the inside range of the scallop, the stress concentration becomes greater with the increase of scallop radius and the tension flange contributes significantly to the bending capacity of corrugated steel web beams. The tests for small-size welded joints indicated their applicability in the analysis and prediction of S-N relationship of the test corrugated steel web beams. Finally, the fatigue crack propagation lives of weld joints were compared with those of test corrugated steel web beams with respect to related design Categories of the AASHTO LRFD Bridge Design Specifications. © 2013 Korean Society of Steel Construction and Springer-Verlag Berlin Heidelberg.
Cao P.Z.,Hohai University |
Li D.,Hohai University |
Lin R.Z.,Yunnan Electrical Power Design Institute
Applied Mechanics and Materials | Year: 2014
A new Steel deck-concrete composite floor slabs was proposed that with the effect of het preservation and insulation, and the flexure performance of the slabs has been studied. Calculation method of flexural bearing capacity was put forward. Based on comparative and analysis experimental results, it has been verified that the applicability of new formula of flexural bearing capacity of the new slabs. © (2014) Trans Tech Publications, Switzerland.
Wang J.-H.,YunNan Electrical power design institute |
Zhao C.-H.,YunNan Electrical power design institute
Applied Mechanics and Materials | Year: 2014
To study the slimes engineering properties of Pingguo Alumina Industry Company bauxite tailings that accumulated under natural conditions, Site test and laboratory test are used. Test results show that the oxide of the bauxite are alumina, silicon dioxide, ferric oxide; the mineral composition are mainly kaolinite, hydrogarnet and hematite; the grain of the slimes are silt and clay with a small amount of sand; the microscopic structure of bauxite is "super impracticable structure"; the total pore volume is 0.441ml/g; the total pore surface area is 6.747m2/g; the specific surface area of the grain is 131.53m2/g; the main ion exchange is K+ and the exchange capacity is 0.26-0.32mg/g; the average coefficient of permeability is 3.05×10-6cm/se; the average moisture content is 130.3%; the average limit of liquidity is 57.1%; the average coefficient of compressibility is 0.79; the average cohesion is 23kPa; the average internal friction angle is 10.2°, so the slimes is high liquid limit, high compression and low shear strength soil; the water holding capacity of the slimes is 79∼93%; the slurry concentration which had stacked more than 18 months is 49.92%, so the slimes is slurry. © (2014) Trans Tech Publications, Switzerland.
Wang R.,Wuhan University |
Li G.,Yunnan Electrical Power Design Institute
Tumu Jianzhu yu Huanjing Gongcheng/Journal of Civil, Architectural and Environmental Engineering | Year: 2015
The flat steel box girder is commonly used for long-span cable-stayed bridges. the structural complexity, construction details and manufactures cause damage to the bridge and the damages seriously grow overtime. The main reason for these damages is that welding technology of flat steel box girder with thin plates and rib elements produces residual stress and strain fields during the welding process, and further more welding cracks commonly appear. In this study, thermal-structural couple methods was adopted to numerically simulate the welding high temperature fields and the stress fields at the joint of U rid and decks of a flat steel box. The welding residual stress distribution was studied as well for further analyzing on the structural damage and strengthening design strategies. ©, 2015, China National Publications Import and Export (Group) Corporation. All right reserved.
Du L.,Chongqing University |
Li X.,Chongqing University |
Sima W.,Chongqing University |
Dai B.,Yunnan Electrical Power Design Institute
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2012
S-transform modular matrix and LS-SVM (Least Square-Support Vector Machine) are applied to identify the lightning overvoltage and switching overvoltage. The singular value decomposition decomposes the S-transform modular matrix of zero sequence overvoltage signals into different time-frequency characteristic subspaces, from which five statistical features are extracted and used as the input vectors of the LS-SVM classifiers to identify the lightning and switching overvoltages. Results of the test with measured overvoltage data indicate that, the characteristic dimension is small, the features are immune to electromagnetic noises, the training times is low, and the recognition rate is high. The proposed method can be well applied in identification of lightning and switching overvoltages.
Yang Y.,Chongqing University |
Li L.,Chongqing University |
Du L.,Chongqing University |
Li X.,Hunan Electrical Power Research Institute |
And 2 more authors.
Dianwang Jishu/Power System Technology | Year: 2012
It is significant for improving and enhancing insulation coordination level of power system to identify lightning and switching surges. Based on singular value decomposition (SVD) of time-frequency matrix and support vector machine (SVM), a method to identify lightning and switching surges is proposed. Through applying wavelet decomposition to voltage signals a multi-scale time-frequency matrix is constructed, then this time-frequency matrix is decomposed by SVD and the signal components are decomposed into different time-frequency characteristic subspaces to attain singular spectrum of voltage signal, and characteristic quantities of singular spectrum are calculated and taken them as the input vectors of multilevel SVM to identify lightning and switching surges. Calculation results of five overvoltage signals measured in a certain substation show that the dimensionality of the extracted characteristic quantities is low and extracted characteristic quantities possess relative stability to electromagnetic disturbances in overvoltage signals; less training samples are needed for the proposed identification method that exists high recognition rate. Thus, using the proposed method, lightning and switching surges can be classified accurately.
PubMed | Hunan University and Yunnan Electrical Power Design Institute
Type: | Journal: TheScientificWorldJournal | Year: 2014
Considering the limited resources and the dynamic spectrum distribution in the cognitive radio sensor networks (CRSN), a half-duplex Multichannel broadcast protocol for CRSN is presented based on the home channel. This protocol maintains the networks topology only through the home channel, so there is no need for the public channel to transmit the control information and no need for the synchronization. After network initialization, node broadcasts data via home channel in half-duplex transmission way. The simulation results show that, compared with complete broadcast, the proposed protocol effectively reduces broadcast delay and overhead.