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Experimental study and calculation of flexural capacity of RC beams strengthened with GFRP sheets
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作者 王文炜 李果 《Journal of Southeast University(English Edition)》 EI CAS 2004年第2期229-234,共6页
Nine reinforced concrete (RC) beams strengthened by glass fiber reinforced polymer (GFRP) sheets and three control beams are tested. Four parameters are considered in this experimental program included the concrete st... Nine reinforced concrete (RC) beams strengthened by glass fiber reinforced polymer (GFRP) sheets and three control beams are tested. Four parameters are considered in this experimental program included the concrete strength, the reinforcement ratio, the number of GFRP sheets, and the shear span ratio. It is shown that the application of GFRP sheets can increase the ultimate flexural capacity. The effect of the concrete strength, the reinforcement ratio and the number of GFRP sheets on load capacity is obvious. The shear span ratio can affect the failure mode of RC beams strengthened by GFRP sheets. A theoretical model for flexural behavior of the strengthened RC beam is also developed. 展开更多
关键词 Bending (deformation) Glass fibers Loads (forces) Reinforced concrete
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Cumulative Deformation of Soft Clay Under Cyclic Loading 被引量:3
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作者 Yan, Shuwang Yan, Chi Zhang, Jianguo 《China Ocean Engineering》 SCIE EI 1993年第3期341-348,共8页
Reconstituted specimens are prepared by means of vacuum preloading. Both static and cyclic triaxial tests are carried out, with the specimens consolidated under different principal stress ratios. A finite element meth... Reconstituted specimens are prepared by means of vacuum preloading. Both static and cyclic triaxial tests are carried out, with the specimens consolidated under different principal stress ratios. A finite element method is put forward for calculating the cumulative deformation of soft clay under cyclic loading. 展开更多
关键词 DEFORMATION Finite element method Loads (forces) Materials testing Ocean engineering Pore pressure Specimen preparation Stresses
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Test Study on Current Force on Mooring Ships 被引量:1
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作者 Zhang, Furan Zhao, Jun Zhang, Xueqin 《China Ocean Engineering》 SCIE EI 1993年第2期225-242,共18页
In respect of an offshore berthing pillar, the test study result of current force acting on mooring ships is described in this paper. Empirical and semi-empirical relationships of current force coefficient are given a... In respect of an offshore berthing pillar, the test study result of current force acting on mooring ships is described in this paper. Empirical and semi-empirical relationships of current force coefficient are given according to the angle between the flow direction and the ship's longitudinal axis, which are coincident with the result of theoretical analysis. 展开更多
关键词 Flow of water Loads (forces) Mathematical models Numerical methods Ocean currents Ship models SHIPS
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Characteristic Aerodynamic Loads and Load Effects on the Dynamics of a Floating Vertical Axis Wind Turbine 被引量:1
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作者 Zhengshun Cheng Puyang Zhang 《Transactions of Tianjin University》 EI CAS 2017年第6期555-561,共7页
The development of offshore wind farms in deep water favors floating wind turbine designs, but floating horizontal axis wind turbines are facing the challenge of high cost of energy (CoE). The development of innovativ... The development of offshore wind farms in deep water favors floating wind turbine designs, but floating horizontal axis wind turbines are facing the challenge of high cost of energy (CoE). The development of innovative designs to reduce the CoE is thus desirable, such as floating vertical axis wind turbines (VAWTs). This study demonstrates the characteristics of aerodynamic loads and load effects of a two-bladed floating VAWT supported by a semi-submersible platform. Fully coupled simulations are performed using the time-domain aero-hydro-servo-elastic code SIMO-RIFLEX-AC. It is found that thrust, lateral force, and aerodynamic torque vary considerably and periodically with the rotor azimuth angle. However, the variation in the generator torque can be alleviated to some extent by the control strategy applied. Moreover, the variations of platform motions and tensions in the mooring lines are strongly influenced by turbulent winds, whereas those of tower-base bending moments are not. The tower-base bending moments exhibit notable two-per-revolution (2P) response characteristics. © 2017 Tianjin University and Springer-Verlag GmbH Germany 展开更多
关键词 Aerodynamic loads AERODYNAMICS Bending moments Loads (forces) Mooring cables Offshore wind farms Wind power
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Dynamic Response Analysis of Risers Subjected to Combined Wave and Current Loading
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作者 Nie, Wu Yu, Xiukun +1 位作者 Ma, Chunyan Li, Weiyang 《China Ocean Engineering》 SCIE EI 1993年第2期147-156,共10页
A dynamic response analysis in the frequency domain is presented for risers subjected to combined wave and current loading. Considering the effects of current, a modified wave spectrum is adopted to compute the linear... A dynamic response analysis in the frequency domain is presented for risers subjected to combined wave and current loading. Considering the effects of current, a modified wave spectrum is adopted to compute the linearized drag force. An additional drag force convolution term is added to the linearized drag force spectrum, therefore the error is reduced which arises from the truncation of higher order terms in the drag force auto-correlation function. An expression of linearized drag force spectrum is given taking the relative velocity into account. It is found that the additional term is a fold convolution integral. In this paper dynamic responses of risers are investigated, while the influence of floater motion on risers is considered. The results demonstrate that the accuracy of the present method reaches the degree required in time domain analysis. 展开更多
关键词 Drag Dynamic loads Dynamic response Frequency domain analysis Loads (forces) Ocean currents Spectrum analysis Time domain analysis VELOCITY Water waves
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Local Joint Flexibility Multibrace Tubular Joints
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作者 Chen, Tieyun Zhang, Huiyuan 《China Ocean Engineering》 SCIE EI 1993年第2期125-138,共14页
The local joint flexibility matrix of multibrace tubular joints (uniplanar and multiplanar joints) is defined. The formulation for computing the elements of local flexibility factor matrix of multibrace tubular joints... The local joint flexibility matrix of multibrace tubular joints (uniplanar and multiplanar joints) is defined. The formulation for computing the elements of local flexibility factor matrix of multibrace tubular joints by semi-analytic method is presented in this paper. The stiffening effect of unloaded braces and cross-flexibility between braces are discussed. Using the local flexibility of unibrace joints instead of that of multibrace joints in conventional structural analysis will lead the result to an unsafe side. 展开更多
关键词 DEFORMATION Flexible structures Loads (forces) Mechanical properties Numerical methods Production platforms Structural analysis
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STUDY ON ACTIVE CONTROL FOR A FLEXIBLE BEAM UNDER THE CONDITION OF ZERO GRAVITY
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作者 员超 宗光华 张启先 《Chinese Journal of Aeronautics》 SCIE EI CSCD 2000年第1期51-58,共8页
The system of coupling structure with controlling is a kind of dynamic feedback system in which the mechanical load and the actuator/controller interact. The mechanical system and the control system can be considered ... The system of coupling structure with controlling is a kind of dynamic feedback system in which the mechanical load and the actuator/controller interact. The mechanical system and the control system can be considered integrally as a close system, and the driving forces actuating the mechanical load can be taken as inner forces in the coupling structure system with controlling. Therefore, one can use the method for dealing with conservative systems to simplify greatly modeling and analyses. The relative equilibrium state of motion of the flexible beam under the condition of zero gravity is studied by using the energy method, in which the characteristics of structure and controlling are considered synthetically. And further, the stability conditions for the relative equilibrium state of the system have been found. If the stability conditions are used as controlling parameters of motion of the system, the kinetic energy of the flexible beam can be converted advantageously into the electromagnetic energy of the motor and controller as well as the vibration of the flexible structure can be reduced rapidly. The results in the research provide a kind of very simple and effective real-time control method reducing the vibration of the flexible beam. The method has been verified in many kinds of experimental systems of flexible beams. 展开更多
关键词 Actuators Control systems Feedback control GRAVITATION Kinetic energy Loads (forces) Motion control Numerical methods System stability Vibration control
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Structural Analysis of Platforms with the Effect of Joint Flexibility
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作者 Mu, Yang Zhang, Shengkun 《China Ocean Engineering》 SCIE EI 1993年第3期243-252,共10页
A modified space beam element is presented in this paper to consider the local joint flexibility of T, Y tubular joints subjected to axial forces and in-plane bending moments for analysis of platforms. Two numerical e... A modified space beam element is presented in this paper to consider the local joint flexibility of T, Y tubular joints subjected to axial forces and in-plane bending moments for analysis of platforms. Two numerical examples are shown to verify the efficiency and validity of the method presented here. 展开更多
关键词 Bending (deformation) Joints (structural components) Loads (forces) Mathematical models Ocean engineering Structural analysis WELDS
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ITERATIVE COMPUTATION METHOD FOR NONLINEAR FORCED VIBRATION EQUATION ON HELICOPTER MAIN ROTOR LOAD
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作者 Liu Xiangjian Shen Xinkang Xue Zhengzhong( Chinese Helicopler Rcsearch and Development institute,Jindezhen , China, 333001 ) 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 1995年第1期22-28,共7页
ITERATIVECOMPUTATIONMETHODFORNONLINEARFORCEDVIBRATIONEQUATIONONHELICOPTERMAINROTORLOADLiuXiangjian;ShenXinka... ITERATIVECOMPUTATIONMETHODFORNONLINEARFORCEDVIBRATIONEQUATIONONHELICOPTERMAINROTORLOADLiuXiangjian;ShenXinkang;XueZhengzhong(... 展开更多
关键词 rotary wings vibration effects load (forces) iterative solution
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EXPERIMENTAL STUDIES ON DYNAMIC PROPAGATION OF CRACKS UNDER BIAXIAL COMPRESSION
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作者 Yu, Hengwen Song, Jinliang +1 位作者 Feng, Deyi Jian, Chun 《Acta Mechanica Solida Sinica》 SCIE EI 1994年第3期211-220,共10页
This paper deals with the initiation and non-coplaner propagation of cracks under biaxial compression. The running process of the propagating cracks is successfully recorded with the method of dynamic photoelasticity.... This paper deals with the initiation and non-coplaner propagation of cracks under biaxial compression. The running process of the propagating cracks is successfully recorded with the method of dynamic photoelasticity. A series of important fracture parameters such as cracks propagating velocity, critical opening loading and initial angle of cracks growth under biaxial compression is calculated. Results show that the stress field in front of the non-closed crack tip under biaxial compression is a mixed-mode singular field, the dynamic propagation of the new tensile cracks is just stable and shows distinct stages, but the unstable crack appears under high loads and results in the rupture of the matrix. 展开更多
关键词 Failure (mechanical) FRACTURE Fracture mechanics Loads (forces) PHOTOELASTICITY Stability Stresses VELOCITY
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DAMAGE ANALYSIS BY BOUNDARY ELEMENT METHOD
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作者 Z.Z.Cen G.Swoboda F.Ito 《Acta Mechanica Solida Sinica》 SCIE EI 1994年第3期245-255,共11页
The response of cracked bodies subjected to loading was investigated by the boundary element method in this paper. The two-law elastic-cohesive-softening model was used for crack propagation analysis. The interface co... The response of cracked bodies subjected to loading was investigated by the boundary element method in this paper. The two-law elastic-cohesive-softening model was used for crack propagation analysis. The interface conditions for uncracked, craze, open crack, adhesive crack and slid crack parts were discussed and the corresponding incremental iteration algorithm was given. A simplified damage propagation model was presented. The technique has been applied to some specific examples which give the evidence that the method is satisfactory and efficient. 展开更多
关键词 ALGORITHMS Boundary element method Crack propagation Cracks Dynamic response ELASTICITY Fracture mechanics Interfaces (materials) Iterative methods Loads (forces) Mathematical models
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ForCES体系结构下路由器内部路由机制 被引量:2
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作者 吴海博 徐明伟 《清华大学学报(自然科学版)》 EI CAS CSCD 北大核心 2008年第1期124-127,共4页
控制和转发单元分离结构(forwarding and control element separation,ForCES)路由器必须能够支持上百个转发单元(forwarding element,FE),为解决分组在路由器内部的路由问题,在ForCES路由器拓扑发现的基础上,提出基于标签的内部路由机... 控制和转发单元分离结构(forwarding and control element separation,ForCES)路由器必须能够支持上百个转发单元(forwarding element,FE),为解决分组在路由器内部的路由问题,在ForCES路由器拓扑发现的基础上,提出基于标签的内部路由机制。引入备份路径减少了路由恢复时间。若n代表FE结点数,m代表含外部接口的FE数,e代表平均边数,则该机制与OSPF(open shortest path first)相比,计算量由O(n3)减小为O(mn2),通信开销由ne的数量级减至n的数量级。实验结果表明:转发表更新算法的计算开销优于OSPF。该机制收敛速度快,通信开销小,路径发生故障时能够快速恢复。 展开更多
关键词 计算机网络 控制和转发单元分离(forces) 路由器内部路由 标签 备份路径
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TIME-DOMAIN SOLUTIONS FOR HYDRODYNAMIC FORCES AND MOMENTS ACTING ON A 3-D BODY MOVING IN WAVES 被引量:2
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作者 Zhang, Liang 《Journal of Hydrodynamics》 SCIE EI CSCD 1993年第2期110-113,共4页
In this paper, based on transient free-surface Green function and panel method, accurate wave exciting forces and moments acting on an arbitrary 3-D body moving at constant forward speed are given by using a time doma... In this paper, based on transient free-surface Green function and panel method, accurate wave exciting forces and moments acting on an arbitrary 3-D body moving at constant forward speed are given by using a time domain algorithm under the condition of a linearized free surface. 展开更多
关键词 Algorithms Diffraction Fluid structure interaction Loads (forces) Three dimensional Time domain analysis Water wave effects
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VERIFICATION AND COMPARISON OF FORMULAS FOR BED LOAD TRANSPORT 被引量:3
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作者 Wang, X.K. Li, D.X. +1 位作者 Qu, Z.S. Wang, D.C. 《Journal of Hydrodynamics》 SCIE EI CSCD 2001年第1期8-11,共4页
Several typical formulas for bed load transport are examined based on field data. It is concluded that the Einstein formula provides good estimates for the bed load transport rate while other ones predict much lower t... Several typical formulas for bed load transport are examined based on field data. It is concluded that the Einstein formula provides good estimates for the bed load transport rate while other ones predict much lower transport rates. The main reason for the under-prediction is that Dp, the effective diameter of particles, is too large as a representative diameter of the bed material for gravel streams with partially movable bed. Performance of these formulas can be significantly improved if D35 is adopted instead of Dp. 展开更多
关键词 Loads (forces) Structural loads
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Aerostatic Stability of Long-Span Cable-Stayed Bridges: Parametric Study 被引量:1
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作者 程进 江见鲸 +1 位作者 肖汝诚 项海帆 《Tsinghua Science and Technology》 SCIE EI CAS 2003年第2期201-205,共5页
This paper presents a method to analyze the nonlinear aerostatic stability of cable-stayed bridges including all three components of the wind load and the geometric nonlinearity. The analysis was used to investigate t... This paper presents a method to analyze the nonlinear aerostatic stability of cable-stayed bridges including all three components of the wind load and the geometric nonlinearity. The analysis was used to investigate the effects of the wind angle of incidence, the wind load of individual bridge elements, the sagging of cable elements, the changes of tower height and the changes of side span length on the aerostatic stability of cable-stayed bridges. The results show that the wind angle of incidence and the wind loads on the cables have an important effect on the aerostatic stability of cable-stayed bridges. 展开更多
关键词 Loads (forces) STABILITY
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EXPERIMENTAL STUDY ON THE SECOND-ORDER DIFFRACTION WAVE PRESSURE AND FORCE ON A CIRCULAR CYLINDER UNDER STOKES WAVE ACTION
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作者 Zhou, Zhi-li Tian, Yong-an +1 位作者 Dai, Yi-shan Huang, Wei-li 《Journal of Hydrodynamics》 SCIE EI CSCD 1993年第2期94-103,共10页
This paper presents the model test to measure the second-order wave pressure and forces on a circular cylinder fixed in Stokes wave with a given draught. The distributions of second-order oscillating and steady wave p... This paper presents the model test to measure the second-order wave pressure and forces on a circular cylinder fixed in Stokes wave with a given draught. The distributions of second-order oscillating and steady wave pressure on the wet surface of the cylinder and second order oscillating wave forces were obtained in this test, but the second-order steady wave force was not able to be measured due to its very small magnitude. The test results also show that third-order wave force may be greater than the second-order force when wave frequencies are high. The experimental results were compared with the corresponding calculation results of Reference [3]. 展开更多
关键词 Cylinders (shapes) DIFFRACTION Fluid structure interaction Force measurement HYDRODYNAMICS Loads (forces) Mathematical models Pressure effects
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