The wind-induced dynamic response of long-span light-weight steel arch structure of the global transportation center (GTC) of Beijing Capital International Airport was studied. A composite technique with combination o...The wind-induced dynamic response of long-span light-weight steel arch structure of the global transportation center (GTC) of Beijing Capital International Airport was studied. A composite technique with combination of WAWS(Weighted Amplitude Wavelet Superposition) and FFT(Fast Fourier Transformation) was introduced to simulate wind velocity time series of hundreds of spatial points simultaneously. The structural shape factors of wind load was obtained from wind tunnel model test. The wind vibration factor based on structural displacement response was investigated. After comparing the computational results with wind tunnel model test data, it was found out that the two results accord with each other if wind comes from 0° direction angle, but are quite different if wind comes from 180° direction angle in the area blocked off by airport terminals. The possible reasons of this difference were analyzed. Haar wavelet was used to transform and analyze wind velocity time series and structural wind-induced dynamic responses. The relationship between exciting wind loads and structural responses was studied in time and frequency domains.展开更多
A new fluid bag buffer mechanism,which can provide large axial stiffness under the small displacement,is designed.The dynamic change laws of the mechanism stiffness and the internal pressure of the fluid bag are studi...A new fluid bag buffer mechanism,which can provide large axial stiffness under the small displacement,is designed.The dynamic change laws of the mechanism stiffness and the internal pressure of the fluid bag are studied when it is subjected to impact load.According to the protection performance for the flexible joint and the pressure change in the fluid bag during the impact process,the sensitivity of the geometric parameters of the fluid bag to the axial stiffness is analyzed by using the orthogonal experimental method,and the optimal parameter combination of the geometric parameters of the fluid bag under impact is obtained,leading to the displacement of the inner shell reduce by 41.4%.The results show that the internal pressure of the fluid bag is a rising process of oscillation and fluctuation.The sensitivity of the geometric parameters of the fluid bag to the displacement of the inner shell from high to low is as follows:Height H,radius r,wall thickness t,chamfer A.The correlation between the geometric parameters of the fluid bag and its internal pressure is:H is negatively correlated with the internal pressure,while the r,t,and A are positively correlated with the internal pressure.展开更多
A FEM model for a failed industrial example of roll forging was established to analyze the generation mechanisms of the mismatch of size and shape of two spring board.To demonstrate the formulation of these defects,th...A FEM model for a failed industrial example of roll forging was established to analyze the generation mechanisms of the mismatch of size and shape of two spring board.To demonstrate the formulation of these defects,the bites condition and contact status between rectangular groove and workpiece during rolling the first and second spring boards were analyzed.Then,a new oval-diamond groove combining oval groove and diamond groove was presented to eliminate these defects.By analyzing field variables under the same deformation degree,the larger friction can be obtained on the contact surface of workpiece and the oval-diamond groove.The physical experiment validates that the oval-diamond groove can eliminate these defects effectively,and the size of part is in good agreement with design requirement.展开更多
FDPSO is a multifunction floating platform,which has the integral function of drilling,production,storage and offloading.A spread mooring system is adopted to position the FDPSO.The coupled analysis in time domain for...FDPSO is a multifunction floating platform,which has the integral function of drilling,production,storage and offloading.A spread mooring system is adopted to position the FDPSO.The coupled analysis in time domain for FDPSO system is conducted in the present paper,using the code DeepC.The effect of axial stiffness of the mooring line on the horizontal motion of FDPSO is studied by employing five types of different axial stiffness in the calculation of the motion response of FDPSO vessel.Furthermore,the results of a model test conducted in the State Key Laboratory of Ocean Engineering in Shanghai Jiao Tong University are used to investigate the feasibility of the numerical method.展开更多
This paper considers the Legendre Galerkin spectral approximation for the unconstralnea optimal control problems. The authors derive a posteriori error estimate for the spectral approximation scheme of optimal control...This paper considers the Legendre Galerkin spectral approximation for the unconstralnea optimal control problems. The authors derive a posteriori error estimate for the spectral approximation scheme of optimal control problem. By choosing the appropriate basis functions, the stiff matrix of the discretization equations is sparse. And the authors use the Fast Legendre Transform to improve the efficiency of this method. Two numerical experiments demonstrating our theoretical results are presented.展开更多
The steel plate shear wall system has been used in a number of buildings as an innovative lateral force resistant system.Openings often exist in the steel plate shear walls due to the various functional requirements o...The steel plate shear wall system has been used in a number of buildings as an innovative lateral force resistant system.Openings often exist in the steel plate shear walls due to the various functional requirements of structures.These openings may negatively impact the lateral stiffness of steel plate shear walls.Therefore,an experimental research was instituted to investigate the seismic behavior of steel plate shear walls,with and without openings.The experimental results showed that steel plate shear walls have the satisfying seismic behavior,and,as expected,the strength and stiffness characteristics of the walls were reduced due to openings.Then a single-story wall panel FE model and an analytical deep beam model are developed in order to find the critical factors dominating the thickness reduction coefficient of wall panels with the opening.Furthermore,extensive parametric analysis is conducted to derive a simplified formula for the determination of the thickness reduction coefficient of wall panels with the opening for substituting solid wall panels with reduced thickness for actual wall panels with the opening.Finally,the design method for calculating the lateral stiffness is verified by some experimental programs and recommended for the routine practice of steel plate shear walls.展开更多
基金National Natural Science Foundation ofChina (No.50278054) and the Fund ofScience and Technology Development ofShanghai (No.04JC14059)
文摘The wind-induced dynamic response of long-span light-weight steel arch structure of the global transportation center (GTC) of Beijing Capital International Airport was studied. A composite technique with combination of WAWS(Weighted Amplitude Wavelet Superposition) and FFT(Fast Fourier Transformation) was introduced to simulate wind velocity time series of hundreds of spatial points simultaneously. The structural shape factors of wind load was obtained from wind tunnel model test. The wind vibration factor based on structural displacement response was investigated. After comparing the computational results with wind tunnel model test data, it was found out that the two results accord with each other if wind comes from 0° direction angle, but are quite different if wind comes from 180° direction angle in the area blocked off by airport terminals. The possible reasons of this difference were analyzed. Haar wavelet was used to transform and analyze wind velocity time series and structural wind-induced dynamic responses. The relationship between exciting wind loads and structural responses was studied in time and frequency domains.
基金supported by the Fun⁃damental Scientific Research Business Expenses of Central Universities(No.NJ2020024).
文摘A new fluid bag buffer mechanism,which can provide large axial stiffness under the small displacement,is designed.The dynamic change laws of the mechanism stiffness and the internal pressure of the fluid bag are studied when it is subjected to impact load.According to the protection performance for the flexible joint and the pressure change in the fluid bag during the impact process,the sensitivity of the geometric parameters of the fluid bag to the axial stiffness is analyzed by using the orthogonal experimental method,and the optimal parameter combination of the geometric parameters of the fluid bag under impact is obtained,leading to the displacement of the inner shell reduce by 41.4%.The results show that the internal pressure of the fluid bag is a rising process of oscillation and fluctuation.The sensitivity of the geometric parameters of the fluid bag to the displacement of the inner shell from high to low is as follows:Height H,radius r,wall thickness t,chamfer A.The correlation between the geometric parameters of the fluid bag and its internal pressure is:H is negatively correlated with the internal pressure,while the r,t,and A are positively correlated with the internal pressure.
基金Project(51275543)supported by the National Natural Science Foundation of ChinaProject(cstc2009aa3012-1)supported by the Key Program of Chongqing Science and Technology Foundation,China
文摘A FEM model for a failed industrial example of roll forging was established to analyze the generation mechanisms of the mismatch of size and shape of two spring board.To demonstrate the formulation of these defects,the bites condition and contact status between rectangular groove and workpiece during rolling the first and second spring boards were analyzed.Then,a new oval-diamond groove combining oval groove and diamond groove was presented to eliminate these defects.By analyzing field variables under the same deformation degree,the larger friction can be obtained on the contact surface of workpiece and the oval-diamond groove.The physical experiment validates that the oval-diamond groove can eliminate these defects effectively,and the size of part is in good agreement with design requirement.
基金supported by the National Scientific and & Technology Major Project (Grant No.2008zx05026-006)
文摘FDPSO is a multifunction floating platform,which has the integral function of drilling,production,storage and offloading.A spread mooring system is adopted to position the FDPSO.The coupled analysis in time domain for FDPSO system is conducted in the present paper,using the code DeepC.The effect of axial stiffness of the mooring line on the horizontal motion of FDPSO is studied by employing five types of different axial stiffness in the calculation of the motion response of FDPSO vessel.Furthermore,the results of a model test conducted in the State Key Laboratory of Ocean Engineering in Shanghai Jiao Tong University are used to investigate the feasibility of the numerical method.
基金supported by the Foundation for Talent Introduction of Guangdong Provincial University,Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2008)the National Natural Science Foundation of China under Grant No.10971074
文摘This paper considers the Legendre Galerkin spectral approximation for the unconstralnea optimal control problems. The authors derive a posteriori error estimate for the spectral approximation scheme of optimal control problem. By choosing the appropriate basis functions, the stiff matrix of the discretization equations is sparse. And the authors use the Fast Legendre Transform to improve the efficiency of this method. Two numerical experiments demonstrating our theoretical results are presented.
基金supported by the National Key Technology R&D Program of China(Grant No.2011BAJ09B01)the National Natural Science Foundation of China(Grant Nos.51178246,51222810)Tsinghua University Initiative Scientific Research Program(Grant No.20101081766)
文摘The steel plate shear wall system has been used in a number of buildings as an innovative lateral force resistant system.Openings often exist in the steel plate shear walls due to the various functional requirements of structures.These openings may negatively impact the lateral stiffness of steel plate shear walls.Therefore,an experimental research was instituted to investigate the seismic behavior of steel plate shear walls,with and without openings.The experimental results showed that steel plate shear walls have the satisfying seismic behavior,and,as expected,the strength and stiffness characteristics of the walls were reduced due to openings.Then a single-story wall panel FE model and an analytical deep beam model are developed in order to find the critical factors dominating the thickness reduction coefficient of wall panels with the opening.Furthermore,extensive parametric analysis is conducted to derive a simplified formula for the determination of the thickness reduction coefficient of wall panels with the opening for substituting solid wall panels with reduced thickness for actual wall panels with the opening.Finally,the design method for calculating the lateral stiffness is verified by some experimental programs and recommended for the routine practice of steel plate shear walls.
