Experimental research and numerical analysis were applied to study the ultimate load capacity(ULC) and reinforcement of circular-hollow-section N-joint.Four specimens were tested under static load.The ULC of each spec...Experimental research and numerical analysis were applied to study the ultimate load capacity(ULC) and reinforcement of circular-hollow-section N-joint.Four specimens were tested under static load.The ULC of each specimen was obtained and the detailed failure conditions were discussed.Based on the results, both welding a plate on the chord member and filling concrete in the chord member are effective to reinforce the N-joint, but it is suggested that these two methods should not be applied simultaneously.Mo...展开更多
Faults in rotating machine are difficult to detect and identify,especially when the system is complex and nonlinear.In order to solve this problem,a novel performance monitoring and fault diagnosis method based on ker...Faults in rotating machine are difficult to detect and identify,especially when the system is complex and nonlinear.In order to solve this problem,a novel performance monitoring and fault diagnosis method based on kernel generalized discriminant analysis(kernel GDA,KGDA)was proposed.Through KGDA,the data were mapped from the original space to the high-dimensional feature space.Then the statistic distance between normal data and test data was constructed to detect whether a fault was occurring.If a fault had occurred,similar analysis was used to identify the type of faults.The effectiveness of the proposed method was evaluated by simulation results of vibration signal fault dataset in the rotating machinery,which was scalable to different rotating machinery.展开更多
Pushover analysis is common because of its conceptual simplicity and computational attractiveness in computing seismic demand.Considering that traditional pushover analysis is restricted in underground structures due ...Pushover analysis is common because of its conceptual simplicity and computational attractiveness in computing seismic demand.Considering that traditional pushover analysis is restricted in underground structures due to the stark differences in the seismic response characteristics of surface structures,this paper proposes a pushover analysis method for underground structures and its application in seismic damage assessment.First,three types of force distribution are presented based on ground response analysis.Next,the target displacements and analysis models are established according to force-based and performance-based design.Then,the pushover analysis procedure for underground structures is described.Next,the applicability of pushover analysis to underground structures is verified by comparing the responses of a Chongwenmen subway station determined by the proposed procedure and by nonlinear response history analysis.In addition,two other points are made:that the inverted triangular distribution of effective earthquake acceleration is more practical than the other two distributions,and that performance-based design is more effective than force-based design.Finally,a cyclic reversal loading pattern based on one cycle of reversal loads as an earthquake event is presented and applied to the seismic damage assessment of underground structures.The results show that the proposed pushover analysis can be effectively applied to the seismic design and damage assessment of underground structures.展开更多
基金Supported by National Natural Science Foundation of China (No.50608054)
文摘Experimental research and numerical analysis were applied to study the ultimate load capacity(ULC) and reinforcement of circular-hollow-section N-joint.Four specimens were tested under static load.The ULC of each specimen was obtained and the detailed failure conditions were discussed.Based on the results, both welding a plate on the chord member and filling concrete in the chord member are effective to reinforce the N-joint, but it is suggested that these two methods should not be applied simultaneously.Mo...
基金National Natural Science Foundation of China(No.60504033)
文摘Faults in rotating machine are difficult to detect and identify,especially when the system is complex and nonlinear.In order to solve this problem,a novel performance monitoring and fault diagnosis method based on kernel generalized discriminant analysis(kernel GDA,KGDA)was proposed.Through KGDA,the data were mapped from the original space to the high-dimensional feature space.Then the statistic distance between normal data and test data was constructed to detect whether a fault was occurring.If a fault had occurred,similar analysis was used to identify the type of faults.The effectiveness of the proposed method was evaluated by simulation results of vibration signal fault dataset in the rotating machinery,which was scalable to different rotating machinery.
基金supported by the Tsinghua Initiative Scientific Research Program(Grant No.2012THZ02-2)Beijing Natural Science Foundation(Grant No.8111001)+1 种基金National Basic Research Program of China(Grant No.2011CB013602)Major Research Plan of the National Natural Science Foundation of China(Grant No.91215301)
文摘Pushover analysis is common because of its conceptual simplicity and computational attractiveness in computing seismic demand.Considering that traditional pushover analysis is restricted in underground structures due to the stark differences in the seismic response characteristics of surface structures,this paper proposes a pushover analysis method for underground structures and its application in seismic damage assessment.First,three types of force distribution are presented based on ground response analysis.Next,the target displacements and analysis models are established according to force-based and performance-based design.Then,the pushover analysis procedure for underground structures is described.Next,the applicability of pushover analysis to underground structures is verified by comparing the responses of a Chongwenmen subway station determined by the proposed procedure and by nonlinear response history analysis.In addition,two other points are made:that the inverted triangular distribution of effective earthquake acceleration is more practical than the other two distributions,and that performance-based design is more effective than force-based design.Finally,a cyclic reversal loading pattern based on one cycle of reversal loads as an earthquake event is presented and applied to the seismic damage assessment of underground structures.The results show that the proposed pushover analysis can be effectively applied to the seismic design and damage assessment of underground structures.
