scholarly journals The fitting of the viscous dampers to dampen the torsional vibration of the combustion engine’s crank shaft

2018 ◽  
Vol 19 (6) ◽  
pp. 482-485
Author(s):  
Celina Jagiełowicz-Ryznar
Keyword(s):  
Torsional Vibration ◽  
Test Bench ◽  
Damping Coefficient ◽  
Theoretical Formula ◽  
Damping Factor ◽  
Viscous Damper ◽  
Special Test ◽  
Viscous Dampers

The method of viscous damper fitting, on the base of damping factor of viscous torsion damper, was presented in this paper. The measurements of forced torsional vibration of measuring shaft with damper, on the special test bench are the basis of the method. According to the theoretical formula, including the results of the vibrations measuring, the damping coefficient was determined.

Seismic Reduction and Control Analysis of Hybrid Structure with Viscous Dampers under Strong Earthquake

2014 ◽  
Vol 580-583 ◽  
pp. 1633-1636 ◽  
Author(s):  
Sen Qiu ◽  
Shu Cheng Deng ◽  
Zhao Quan Zhu
Keyword(s):  
Strong Earthquake ◽  
Lateral Displacement ◽  
Hybrid Structure ◽  
Earthquake Ground Motion ◽  
Control Analysis ◽  
Viscous Damper ◽  
Viscous Dampers ◽  
Maximum Value ◽  
Story Drift ◽  
And Control

This article focuses on the effect of viscous damper on seismic performance of steel-concrete hybrid structure under strong earthquake. The result shows that viscous damper has effect on seismic reduction and control. The story lateral displacement, story drift rotation and energy dissipation-seismic can be reduced effectively by viscous dampers. The maximum value of vibration-reduction ratio is 36.0%, 67.9%, 36.9%. It is different effect on seismic reduction by different earthquake ground motion. Response of earthquake amplifies under Pasadena earthquake wave than the others.

scholarly journals Retrofit Existing Frame Structures to Increase Their Economy and Sustainability in High Seismic Hazard Regions

2019 ◽  
Vol 9 (24) ◽  
pp. 5486 ◽  
Author(s):  
Shuang Li ◽  
Jintao Zhang
Keyword(s):  
Optimum Design ◽  
Computational Cost ◽  
Time History ◽  
Economic Benefits ◽  
Frame Structure ◽  
Viscous Damper ◽  
Viscous Dampers ◽  
Frame Model ◽  
Rare Earthquake ◽  
Original Frame

The study proposes a retrofitting method with an optimum design of viscous dampers in order to improve the structural resistant capacity to earthquakes. The retrofitting method firstly uses a 2D frame model and places the viscous dampers in the structure to satisfy the performance requirements under code-specific design earthquake intensities and then performs an optimum design to increase the structural collapse-resistant capacity. The failure pattern analysis and fragility analysis show that the optimum design leads to better performance than the original frame structure. For regular structures, it is demonstrated that the optimum pattern of viscous damper placement obtained from a 2D frame model can be directly used in the retrofitting of the 3D frame model. The economic loss and repair time analyses are conducted for the retrofitted frame structure under different earthquake intensities, including the frequent earthquake, the occasional earthquake, and the rare earthquake. Although the proposed method is based on time-history analyses, it seems that the computational cost is acceptable because the 2D frame model is adopted to determine the optimum pattern of viscous damper placement; meanwhile, the owner can clearly know the economic benefits of the retrofitting under different earthquake intensities. The retrofitting also causes the frame to have reduced environmental problems (such as carbon emission) compared to the original frame in the repair process after a rare earthquake happens.

Shake Table Studies on Viscous Dampers in Seismic Control of a Single-Tower Cable-Stayed Bridge Model under Near-Field Ground Motions

2018 ◽  
Vol 12 (05) ◽  
pp. 1850011 ◽  
Author(s):  
Jiang Yi ◽  
Jianzhong Li ◽  
Zhongguo Guan
Keyword(s):  
Ground Motions ◽  
Near Field ◽  
Far Field ◽  
Viscous Damper ◽  
Viscous Dampers ◽  
Damping Force ◽  
Seismic Control ◽  
Cable Stayed Bridge ◽  
Bridge Model ◽  
Cable Stayed Bridges

To investigate the effectiveness of viscous damper on seismic control of single-tower cable-stayed bridges subjected to near-field ground motions, a 1/20-scale full cable-stayed bridge model was designed, constructed and tested on shake tables. A typical far-field ground motion and a near-field one were used to excite the bridge model from low to high intensity. The seismic responses of the bridge model with and without viscous dampers were analyzed and compared. Both numerical and test results revealed that viscous dampers are quite effective in controlling deck displacement of cable-stayed bridges subjected to near-field ground motions. However, due to near-field effects, viscous damper dissipated most energy through one large hysteresis loop, extensively increasing the deformation and damping force demand of the damper. Further study based on numerical analysis reveals that to optimize deck displacement of cable-stayed bridges during an earthquake, a viscous damper with relatively larger damping coefficient should be introduced under near-field ground motions than far-field ones.

Optimal Design of Damper with Stiffness for Damping of Stay Cable under Bridge Deck Motion

2013 ◽  
Vol 438-439 ◽  
pp. 769-774
Author(s):  
Shuai Luo ◽  
Quan Sheng Yan ◽  
Hong Jun Liu
Keyword(s):  
Optimal Design ◽  
Bridge Deck ◽  
Damping Coefficient ◽  
Viscous Damper ◽  
Stay Cable ◽  
Rule Of Thumb ◽  
Modal Damping ◽  
Inclined Angle

This paper studies cable-damper mitigation model due to indirect excitation caused by bridge deck vibration. In the new mitigation model, as a rule of thumb, we considered a parallel association of idealize damper with a spring to simulate the inherent stiffness of the damper. The result shows that the interaction between the stiffness of the viscous damper could deeply impact the damper effectiveness, and the external damping should be increased deeply to provide the same non-dimensional modal damping when the inclined angle of cable decreases. The optimum damping coefficient of the non-idealized damper decreases when the stiffness of the damper increases.

Thermal Stability of Intermetallic Cu–Sn Interconnections for High Temperature Applications

2018 ◽  
Vol 15 (1) ◽  
pp. 35-40
Author(s):  
A. Novikov ◽  
M. Nowottnick
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Test Bench ◽  
Solder Joints ◽  
New Technology ◽  
Solder Paste ◽  
Special Test ◽  
Standard Alloy ◽  
Thermal Stability Of ◽  
Temperature Applications

New technology based on mixing of standard alloy SnCu in form of solder paste with copper paste was presented. This technology allows the production of solder joints with higher standoff consisting of intermetallic compounds. Such solder joints were qualified for high temperature applications by investigation of thermal stability of overlapped solder joints. For this purpose a special test bench for the investigation of remelting temperature up to 300°C was developed.

Simulation Method of Torsional Vibration Waveform of Reciprocating Engine Crankshaft Systems by Transition Matrix Method

1999 ◽  
Author(s):  
Katsuhiko Wakabayashi ◽  
Yasuhiro Honda ◽  
Tomoaki Kodama ◽  
Hiroshi Okamura
Keyword(s):  
Diesel Engines ◽  
Torsional Vibration ◽  
Matrix Method ◽  
Transition Matrix ◽  
High Speed ◽  
Decay Constant ◽  
Damping Ratio ◽  
Damping Coefficient ◽  
Design Stage ◽  
High Speed Diesel

Abstract The torsional vibration of the crankshaft system of high speed diesel engines has become more excessive with the increase of engine power and with the decrease of engine rigidity. So it is necessary in the design stage to improve accuracy in the calculation of maximum torsional vibration amplitude at resonant engine speed. At first, this paper refers to a method for obtaining experimentally engine damping that is necessary for the calculation of torsional vibration. If the value of the damping cannot be accurately estimated, the accuracy of the calculated result is still not satisfactory. In this experiment, the decay constant is obtained from the record of the damped, free torsional vibration waveforms which can be got by stopping abruptly combustion in steady operating. It is also shown that the damping ratio, which is approximately 0.03 to 0.04 in high-speed, small diesel engines, can be got from the already-obtained decay constant. Secondly, authors try to calculate directly resultant amplitude by using a step by step transition matrix method. The simulated waveforms of torsional vibration of a high speed diesel engine are compared with the experimental results and it is shown that the calculated results by the transition matrix method are accurate. At the same time, this paper refers to a method for the estimation of engine damping coefficient that is necessary for the calculation of torsional vibration. In this method, the damping coefficient can be got from the previously obtained damping ratio.

Based on Nonlinear Viscous Dampers Seismic Behavior Research of a Long Span Cable-Stayed Bridge

2011 ◽  
Vol 255-260 ◽  
pp. 1214-1219 ◽  
Author(s):  
Hong Yu Jia ◽  
Shi Xiong Zheng ◽  
Lei Yang ◽  
Ming Qiang Xia
Keyword(s):  
Seismic Behavior ◽  
Vertical Direction ◽  
Time History ◽  
Longitudinal Direction ◽  
Relative Displacement ◽  
Sensitivity Study ◽  
Damping Coefficient ◽  
Viscous Dampers ◽  
Long Span ◽  
Two Parameters

The seismic behavior research of Fengdu Bridge with nonlinear viscous dampers will be conducted to investigate two parameters of damping coefficient C and damping exponent ξ through nonlinear dynamic time-history analysis. Simultaneously, the analysis results are compared with the seismic response without viscous dampers and proposed control methods and formulas of a reasonable selecting damping coefficient C and damping exponent ξ are provided. The parameters sensitivity study indicates that setting dampers in longitudinal direction of bridge can reduce the relative displacement of key positions and the response of the bridge, the beneficial effect of the isolation in the longitudinal direction, but important amplification occurs in the vertical direction for relatively high frequency components. Moreover, the reference of application of nonlinear viscous damper will be provided for similar projects.

Assessment of the Temperature Field of the Viscous Damper GERB Type VES 40/40/40

2009 ◽  
Author(s):  
Ladislav Pecinka ◽  
Pavel Zakovec ◽  
Frank Barutzki
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Ventilation System ◽  
Viscous Damper ◽  
Viscous Dampers ◽  
Damping Coefficients ◽  
Working Temperature ◽  
Crucial Problem ◽  
Stiffness And Damping ◽  
Elastic Elements

GERB pipework viscous dampers are highly effective viscous – elastic elements. The stiffness and damping coefficients of these ones are strongly dependent on the working temperature of the fluid. It is a crucial problem of nuclear power plants if viscous dampers are installed inside the hermetic zone. Circulation of the air due to ventilation system represents either heating or cooling of the damper surface and finally can influenced, the damper reliability. This problem has been solved for the Armenian NPP Metsamor. Results are presented.

scholarly journals Seismic Response Mitigation of a Long-Span Tower Bridge with Two Types of Constraint System

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Li Xu ◽  
Qingfei Gao ◽  
Junhao Zheng ◽  
Chuanhui Ding ◽  
Kang Liu
Keyword(s):  
Element Model ◽  
Main Beam ◽  
Seismic Load ◽  
Viscous Damper ◽  
Viscous Dampers ◽  
Damping Effect ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Drift Frequency ◽  
Nonlinear Finite Element Model

The stress of the main tower of a cable-stayed bridge depends on the connection type between the tower and deck. In order to study the most suitable longitudinal damping mode for a long-span cable-stayed bridge. In this article, a nonlinear finite element model is established based on a large span concrete cable-stayed bridge with a main span of 680 m. Without considering the influence of the transverse constraint, the damping effect of the elastic connection device and the viscous damper is simulated when the longitudinal seismic load is input. The results show that the stiffness of the main beam is increased by installing the elastic connection device, so the longitudinal drift frequency of the main beam is increased, but the stiffness of the structure is not changed by installing the viscous damper. Both viscous dampers and elastic connection structures can reduce the longitudinal displacement of the beam end, but viscous dampers are more favorable for the stress of the main tower. In terms of damping effect, viscous dampers are more suitable for long-span cable-stayed bridges, but, in terms of economy and parameter control, elastic connection devices have more advantages.

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