Control Effect Analysis of a Bridge under Control of Neutral Equilibrium Mechanisms (NEMs) as Multiple Virtual Piers

2020 ◽  
Vol 45 (10) ◽  
pp. 8491-8501
Author(s):  
Ming-Hsiang Shih ◽  
Wen-Pei Sung
Keyword(s):  
Control Effect ◽  
Effect Analysis ◽  
Neutral Equilibrium

Effect Analysis of Different Exhaust Velocity on Fire Smoke Control in Subway Tunnel

2012 ◽  
Vol 424-425 ◽  
pp. 1224-1227
Author(s):  
Xin Han ◽  
Xiao Ming Gao ◽  
Bei Hua Cong
Keyword(s):  
Cfd Simulation ◽  
Simulation Analysis ◽  
Simulation Method ◽  
Subway Tunnel ◽  
Control Effect ◽  
Smoke Control ◽  
Effect Analysis ◽  
Longitudinal Ventilation ◽  
Fire Smoke ◽  
Ventilation Velocity

Taking a subway tunnel as the research object and based on the CFD simulation method, this paper adopts a large eddy simulation analysis software FDS to simulate and analyze the effect of exhaust velocity on fire smoke control under the condition of the same longitudinal ventilation velocity in subway tunnel. The simulated results can provide some reference to design institutes in the selection of exhaust fan. While the longitudinal ventilation velocity set as 1m/s, the simulation results demonstrate that a quite good smoke control effect could be achieved when the exhaust velocity reaches 5 m/s in the smoke exhaust duct

The Control Effect Analysis of the Variable Frequency TMD Applied to the Frame Structure

2012 ◽  
Vol 446-449 ◽  
pp. 3486-3489
Author(s):  
Mao Yu Zhang ◽  
Bo Li ◽  
Yan Ru Wang
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Frame Structure ◽  
Variable Frequency ◽  
Control Effect ◽  
Effect Analysis ◽  
High Rise ◽  
High Rise Building ◽  
Multiple Frequencies ◽  
And Control

Frequency variable TMD system is developed based on the conventional TMD system, which has multiple frequencies and thus merits of MTMD. Frequency variable TMD can effectively reduce the dynamic response of structure induced by its own frequencies. In this study, this technique is applied to dynamic analysis of high-rise building. The results show that frequency variable TMD system can optimize the dynamic response of the structure and control the vibration effectively, compared to conventional TMD system.

Vibration Control Effect Analysis on Tuned Mass Damper System Used in Urban Transportation

2012 ◽  
Vol 468-471 ◽  
pp. 1294-1299 ◽  
Author(s):  
Li Li ◽  
Chuan Zhi Geng ◽  
Ye Tian ◽  
Qing Yu
Keyword(s):  
Vibration Control ◽  
Impact Load ◽  
Effective Means ◽  
Urban Transportation ◽  
Tuned Mass Damper ◽  
Control Effect ◽  
Effect Analysis ◽  
Mass Damper ◽  
Reduction Effect ◽  
And Performance

With the development of urban transportation, vibration and noise control has attracted increasing attention. Vibration and noise level has become one of the important hallmarks of evaluating the influence of urban transportation to environment. As Tuned Mass Damper (TMD) is an effective means of vibration control, there is more and more emphasis on its research and application. Reasonably designed TMD can reduce vibration and noise caused by wheel/rail impact. So how to take into account the complex factors to improve the design of the TMD is still the important issue. TMD system is an effective structure. In order to study its vibration reduction effect, modal calculation and wheel-set drop simulation have been analyzed in this paper. Through varying the mass of TMD, the performance of vibration attenuation have been verified. The stability and performance of damping property under impact load have been confirmed by wheel-set drop simulation. Comparing the track which uses TMD and the normal one, the effect of TMD system can be testified effectively.

scholarly journals Experimental Verification of Applying Active Control Method as Virtual Support for Relief Bridge

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Ming-Hsiang Shih ◽  
Wen-Pei Sung
Keyword(s):  
High Speed ◽  
Control Method ◽  
Disaster Relief ◽  
Moving Load ◽  
Vertical Displacement ◽  
Internal Force ◽  
Control Effect ◽  
Control Gain ◽  
Neutral Equilibrium ◽  
Reduction Effect

When natural disasters cause bridges to collapse, the delivery of rescue equipment and supplies to remote disaster areas is impeded and disaster relief efforts are thus delayed. In this study, to enhance and improve light bridges for disaster relief, a neutral equilibrium mechanism (NEM) is proposed to adjust the internal force of the bridge and reduce the deformation of the bridge. The NEM is installed at the center of a bridge to form a virtual bridge pier. A prototype of the NEM, composed of a pair of prestressed steel tendons, two pairs of anchor seats, a rotation cantilever arm mechanism, and a pair of radio-controlled (RC) servos, is proposed to test and verify the control effect of a bridge with the NEM. Test and analysis results show the following: (1) The rotation angle of the cantilever arm can be rotated by the RC servo to appropriate angles to provide adequate upwards resultant force to balance the moving load. (2) The vertical displacement of the bridge can be controlled to close to zero by this proposed NEM. (3) The maximum vertical displacement at the midpoint of a bridge with the NEM control mechanism can be controlled to far below 1/400 of the span of the bridge required by the design criteria. (4) A bridge under the control of an NEM under a low-speed moving load with various control gains achieves fine displacement reduction effects, but the displacement reduction effect for a high-speed moving load with low control gain decreases. Test results also show that the bearing capacity of an existing bridge with an NEM can be increased and the weight of the bridge can be reduced. The effective span of a bridge can be increased without increasing the depth of the cross section. The feasibility and practicality of applying this proposed NEM to form a virtual pier of a bridge have been verified in this study.

The Research Status and Prospect of Passive Energy Dissipation Technology in Fields of Structural Engineering

2012 ◽  
Vol 166-169 ◽  
pp. 338-342
Author(s):  
Min Chen ◽  
Guo Jing He
Keyword(s):  
Energy Dissipation ◽  
Design Theory ◽  
Structural Engineering ◽  
Performance Based Design ◽  
Economic Losses ◽  
Control Effect ◽  
Effect Analysis ◽  
Research Status ◽  
Passive Energy Dissipation ◽  
Design Idea

This paper generalizes the research status of passive energy dissipation technology in the field of Structural Engineering. Many achievements has been gotten since its emergence, including the manufacture of dampers, the experimental research and control effect analysis for energy dissipation systems, as well as the studies on its optimal design theory, which plays an important role in protecting people's life safety. However, the current design idea mainly focuses on the security, thus the energy dissipation structures will still suffer great economic losses even in moderate earthquakes. As a result, it is quite necessary to introduce the performance-based seismic design idea to study the design theory for passive energy dissipation. This paper has detailed three key problems in performance-based design of passive energy dissipation and put forward some strategy. Finally, it marks out that to study the performance-based design theory in passive energy dissipation system is of great significance in promoting the sustainable development of society.

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