scholarly journals Evaluation of efficiency index of friction energy dissipation devices using endurance time method

2020 ◽  
Vol 5 (2) ◽  
pp. 12-20
Author(s):  
A. Shirkhani ◽  
B. Farahmand Azar ◽  
M. Charkhtab Basim ◽  
◽  
◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Efficiency Index ◽  
Endurance Time ◽  
Endurance Time Method ◽  
Friction Energy ◽  
Energy Dissipation Devices

Optimization and Dynamic Analysis of Frame Structures with Friction Energy Dissipation Device

2005 ◽  
Vol 8 (2) ◽  
pp. 173-181 ◽  
Author(s):  
Yuye Xu ◽  
Bo Wu ◽  
Quanfeng Wang
Keyword(s):  
Energy Dissipation ◽  
Design Procedure ◽  
Sine Wave ◽  
Frame Structure ◽  
Wave Excitation ◽  
C Language ◽  
System Parameters ◽  
Earthquake Records ◽  
Friction Energy ◽  
Energy Dissipation Devices

An analytical solution for a single-damped-storey frame structure system including a friction energy dissipation device under sine wave excitation is presented with an example. A new mathematical model for optimizing some key system parameters in earthquakes is proposed. The model minimizes the sum of brace stiffness that complies with the Chinese seismic code for storey-drift limitations for three given earthquake records. Therefore, the seismic requirements for similar structures can be satisfied with fewer friction energy-dissipation devices. Using the Visual C++ language, a computer program, GAOFF, has been developed to optimize the parameters of a frame structure with friction energy dissipation devices based on three earthquake records using a genetic algorithm. An example of a six-storey RC frame is also presented to demonstrate the effectiveness of the proposed optimal design procedure.

Low-Cycle Fatigue Performance of Buckling Restrained Braces and Assessment of Cumulative Damage under Severe Earthquakes

2018 ◽  
Vol 763 ◽  
pp. 867-874
Author(s):  
Yu Shu Liu ◽  
Ke Peng Chen ◽  
Guo Qiang Li ◽  
Fei Fei Sun
Keyword(s):  
Fatigue Life ◽  
Energy Dissipation ◽  
Structural Reliability ◽  
Low Cycle Fatigue ◽  
Engineering Application ◽  
Fatigue Performance ◽  
Cycle Fatigue ◽  
Variable Amplitude ◽  
Buckling Restrained Braces ◽  
Energy Dissipation Devices

Buckling Restrained Braces (BRBs) are effective energy dissipation devices. The key advantages of BRB are its comparable tensile and compressive behavior and stable energy dissipation capacity. In this paper, low-cycle fatigue performance of domestic BRBs is obtained based on collected experimental data under constant and variable amplitude loadings. The results show that the relationship between fatigue life and strain amplitude satisfies the Mason-Coffin equation. By adopting theory of structural reliability, this paper presents several allowable fatigue life curves with different confidential levels. Besides, Palmgren-Miner method was used for calculating BRB cumulative damages. An allowable damage factor with 95% confidential level is put forward for assessing damage under variable amplitude fatigue. In addition, this paper presents an empirical criterion with rain flow algorithm, which may be used to predict the fracture of BRBs under severe earthquakes and provide theory and method for their engineering application. Finally, the conclusions of the paper were vilified through precise yet conservative prediction of the fatigue failure of BRB.

scholarly journals Dynamic friction energy dissipation and enhanced contrast in high frequency bimodal atomic force microscopy

Friction ◽  
2021 ◽  
Author(s):  
Xinfeng Tan ◽  
Dan Guo ◽  
Jianbin Luo
Keyword(s):  
Atomic Force Microscopy ◽  
Energy Dissipation ◽  
Contact Friction ◽  
Measuring Instruments ◽  
Dynamic Friction ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Friction Energy ◽  
New Applications

AbstractDynamic friction occurs not only between two contact objects sliding against each other, but also between two relative sliding surfaces several nanometres apart. Many emerging micro- and nano-mechanical systems that promise new applications in sensors or information technology may suffer or benefit from noncontact friction. Herein we demonstrate the distance-dependent friction energy dissipation between the tip and the heterogeneous polymers by the bimodal atomic force microscopy (AFM) method driving the second order flexural and the first order torsional vibration simultaneously. The pull-in problem caused by the attractive force is avoided, and the friction dissipation can be imaged near the surface. The friction dissipation coefficient concept is proposed and three different contact states are determined from phase and energy dissipation curves. Image contrast is enhanced in the intermediate setpoint region. The work offers an effective method for directly detecting the friction dissipation and high resolution images, which overcomes the disadvantages of existing methods such as contact mode AFM or other contact friction and wear measuring instruments.

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