To extend the service life of the clinched joint,a reconditioning process conducted with an additional tubular rivet was proposed in this work.Different reconditioning forces were employed to produce dissimilar recond...To extend the service life of the clinched joint,a reconditioning process conducted with an additional tubular rivet was proposed in this work.Different reconditioning forces were employed to produce dissimilar reconditioned joints by experimental method.The experimental results indicated that the neck fracture was the common failure mode of both original clinched and reconditioned joints.Compared with the original clinched joint,the shearing strength of the reconditioned joint produced by a reconditioning force of 40 kN increased from 1810.5 to 1986.47 N,and the energy absorption increased from 2.34 to 3.46 J.The range of effective reconditioning force was from 35 to 40 kN and 40 kN was the best choice for reconditioning the AA5052 failed joints.The mechanical properties of the reconditioned joints are obviously better than those of the original clinched joints,which fully demonstrates that the reconditioning method proposed in this work has a broad prospect of industrial application.展开更多
The advantages, disadvantages and characteristics of various maintenance strategies for modern mechanical equipment are analyzed. Combined with the system structure and functional characteristics of engineering equipm...The advantages, disadvantages and characteristics of various maintenance strategies for modern mechanical equipment are analyzed. Combined with the system structure and functional characteristics of engineering equipment,it puts forward the selection method of maintenance strategies for different types of equipment and failure modes. The view of this article is that the comprehensive maintenance strategy, which is based on condition based maintenance(CBM) and combines various maintenance strategies. This will become the main development direction of engineering equipment maintenance.展开更多
Estimating low-frequency oscillation modes and the corresponding mode shapes based on ambient data from WAMS measurements has a promising prospect in power system analysis and control.Based on the stochastic subspace ...Estimating low-frequency oscillation modes and the corresponding mode shapes based on ambient data from WAMS measurements has a promising prospect in power system analysis and control.Based on the stochastic subspace method,this paper proposes a revised stochastic subspace method by introducing reference channels,which can estimate the modes and the mode shapes simultaneously with great computational efficiency.Meanwhile,the accuracy of the estimated results is not degraded.To discriminate the real modes from the spurious ones,the stabilization diagram is introduced.A novel algorithm is designed to deal with the stabilization diagram which can detect the real modes automatically.Tests conducted on the IEEE-118 system indicate that the proposed method has good performance in terms of both computational efficiency and accuracy,and has the potential of being used on-line.展开更多
基金financial supports from the National Natural Science Foundation of China (No. 51805416)the Young Elite Scientists Sponsorship Program by CAST, China (No. YESS20200279)+3 种基金the Natural Science Foundation of Hunan Province, China (No. 2020JJ5716)the Project of State Key Laboratory of High Performance Complex Manufacturing, Central South University, China (No. ZZYJKT2019-01)the Hunan Provincial Natural Science Foundation for Excellent Young Scholars, China (No. 2021JJ20059)the Huxiang High-Level Talent Gathering Project of Hunan Province, China (No. 2019RS1002)。
文摘To extend the service life of the clinched joint,a reconditioning process conducted with an additional tubular rivet was proposed in this work.Different reconditioning forces were employed to produce dissimilar reconditioned joints by experimental method.The experimental results indicated that the neck fracture was the common failure mode of both original clinched and reconditioned joints.Compared with the original clinched joint,the shearing strength of the reconditioned joint produced by a reconditioning force of 40 kN increased from 1810.5 to 1986.47 N,and the energy absorption increased from 2.34 to 3.46 J.The range of effective reconditioning force was from 35 to 40 kN and 40 kN was the best choice for reconditioning the AA5052 failed joints.The mechanical properties of the reconditioned joints are obviously better than those of the original clinched joints,which fully demonstrates that the reconditioning method proposed in this work has a broad prospect of industrial application.
文摘The advantages, disadvantages and characteristics of various maintenance strategies for modern mechanical equipment are analyzed. Combined with the system structure and functional characteristics of engineering equipment,it puts forward the selection method of maintenance strategies for different types of equipment and failure modes. The view of this article is that the comprehensive maintenance strategy, which is based on condition based maintenance(CBM) and combines various maintenance strategies. This will become the main development direction of engineering equipment maintenance.
基金supported by the National Natural Science Foundation of China (Grant No. 51177079)the Program for Century Excellent Talents in University of China (Grant No. NCET-028-0317)
文摘Estimating low-frequency oscillation modes and the corresponding mode shapes based on ambient data from WAMS measurements has a promising prospect in power system analysis and control.Based on the stochastic subspace method,this paper proposes a revised stochastic subspace method by introducing reference channels,which can estimate the modes and the mode shapes simultaneously with great computational efficiency.Meanwhile,the accuracy of the estimated results is not degraded.To discriminate the real modes from the spurious ones,the stabilization diagram is introduced.A novel algorithm is designed to deal with the stabilization diagram which can detect the real modes automatically.Tests conducted on the IEEE-118 system indicate that the proposed method has good performance in terms of both computational efficiency and accuracy,and has the potential of being used on-line.
