scholarly journals Study on Equivalent Viscous Damping Coefficient of Sucker Rod Based on the Principle of Equal Friction Loss

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Qin Li ◽  
Bo Chen ◽  
Zhiqiang Huang ◽  
Haipin Tang ◽  
Gang Li ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Friction Loss ◽  
Damping Coefficient ◽  
Theoretical Formula ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Equivalent Damping ◽  
Rod System ◽  
Sucker Rod ◽  
Equivalent Damping Coefficient

Equivalent viscous damping coefficient is an important parameter of wave equation for sucker rod string. In this paper, based on the principle of equal friction loss, when the viscous energy consumption and the local damping energy consumption are taken into account, effects of equivalent viscous damping coefficients are obtained. Through deducing energy consumption equation of oil and energy consumption equation of the coupling, theoretical formula for equivalent damping coefficient of sucker rods is received. Results show that the smaller the K is (K is the ratio of sectional area of tubing to sucker rod), the larger the proportion of damping coefficient caused by viscous energy consumption in the equivalent damping coefficient of sucker rod system is. When K< 0.095, the proportion of damping coefficient caused by viscous energy consumption is more than 90%. Reducing the sudden change of cross-section area at sucker rod coupling has remarkable effect on reducing damping force of the sucker rod system. The research provides a theoretical basis for the application and design of sucker rod and tubing.

The Calculation of the Equivalent Linear Damping Coefficient of the Magnetorheological Damper

2013 ◽  
Vol 336-338 ◽  
pp. 475-479 ◽  
Author(s):  
Yao Hui Guo ◽  
En Wei Chen ◽  
Qun Wu ◽  
Yi Min Lu ◽  
Zeng Qiang Xia
Keyword(s):  
Mr Damper ◽  
Magnetorheological Damper ◽  
Damping Coefficient ◽  
Control Voltage ◽  
Characteristic Analysis ◽  
Equivalent Damping ◽  
Equivalent Linear ◽  
Linear Damping ◽  
Damper Control ◽  
Equivalent Damping Coefficient

MR damper (magnetorheological damper) has broad application prospects, and equivalent damping coefficient is very important of its dynamic characteristic analysis. Based on the modified Bouc_Wen model, the performance of MR damper was analyzed and the equivalent linear damping coefficient of MR damper was calculated. Based on simulation date of the modified Bouc_Wen model, the relationships between the equivalent linear damping coefficient of MR damper and the parameters of control voltage and MR dampers movement amplitude were established by the curve fitting regression analysis method. Verification results prove that the equivalent linear damping coefficient model has higher accuracy. For the vibration systems using strongly nonlinear MR damper, new model can effectively improve the efficiency of calculating the vibration analysis and the stability of the system in a certain frequency. At the same time, the model provides a theoretical basis for the application of MR damper control.

Force Behavior of Parallel Double Coupling Beams with Different Width

2014 ◽  
Vol 578-579 ◽  
pp. 707-710
Author(s):  
Ming Li ◽  
Ji Guang Chen ◽  
Wei Jian Zhao ◽  
Li Guo Wang
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Damping Coefficient ◽  
Viscous Damping ◽  
Coupling Beams ◽  
Equivalent Viscous Damping ◽  
Dissipation Coefficient ◽  
Finite Element Software ◽  
Double Coupling ◽  
Energy Dissipation Coefficient

The force behavior of parallel double coupling beams (PDCB) with different width is analyzed, based on which the feasibility of this kind of beams is discussed. The loading process of the PDCB is simulated by using finite element software ABAQUS. By analyzing the hysteretic loops, skeleton curves, energy dissipation coefficient, equivalent viscous damping coefficient and ductility coefficient,the bearing capacity and seismic performance of the PDCB is studied. Through simulation, it shows that the hysteretic loops is plump, and the energy dissipation coefficient, equivalent viscous damping coefficient and ductility coefficient of this double beams is high. It can be concluded that the PDCB has good force behavior, and the beams of PDCB can work in coordination.

NONDIMENSIONAL ANALYSIS OF ANNULAR DUCT FLOW IN MAGNETORHEOLOGICAL/ELECTRORHEOLOGICAL DAMPERS

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1577-1583 ◽  
Author(s):  
JIN-HYEONG YOO ◽  
NORMAN M. WERELEY
Keyword(s):  
Quadratic Equation ◽  
Damping Coefficient ◽  
Viscous Damping ◽  
Uniform Field ◽  
Duct Flow ◽  
Equivalent Viscous Damping ◽  
Performance Metric ◽  
Annular Duct ◽  
Er Damper ◽  
Analytical Expressions

Approximate analytical expressions describing MR/ER damper performance for an axisymmetric annular duct under the assumption of uniform field are presented. The key performance metric is the damping coefficient, which is the ratio of the equivalent viscous damping constant, Ceq, to the Newtonian viscous damping constant, C. To develop these approximations, a quadratic equation was used to approximate the center of the plug location in the annular duct. This equation simplified the calculation of the annular duct solution without resorting to numerical methods to solve the boundary value problem. Approximations for the damping coefficient are developed on this basis.

A new type of damper combining eddy current damping with rack and gear

2020 ◽  
pp. 107754632093711
Author(s):  
Yafeng Li ◽  
Shouying Li ◽  
Jianzhong Wang ◽  
Zhengqing Chen
Keyword(s):  
Eddy Current ◽  
Permanent Magnets ◽  
Air Gap ◽  
Damping Coefficient ◽  
Apparent Mass ◽  
Damping Force ◽  
Equivalent Damping ◽  
Eddy Current Damping ◽  
New Type ◽  
Equivalent Damping Coefficient

A new type of damper combining eddy current damping with rack and gear, which can simultaneously export damping and inertial forces, is proposed. Eddy current damping with rack and gear is supposed to be installed between the building superstructure and foundation to mitigate the seismic response of the building. First, the concept of eddy current damping with rack and gear is introduced in detail and its apparent mass and equivalent damping coefficient are both theoretically investigated. Second, a prototype of eddy current damping with rack and gear is manufactured, and a series of tests on the prototype are carried out to verify its structural parameters. The experimental and theoretical results of the apparent mass of the prototype agree well with each other. The experimental result of the equivalent damping coefficient of the prototype is slightly lower than the numerical results obtained from COMSOL Multiphysics and its maximum relative differences are 11.3% and 13.6% for α = 0° and 45°, respectively. Third, detailed parametric studies on the damping force, including the effects of the thickness of the conductor plate, air gap, and number and location of permanent magnets, are conducted. The results show that the damping force keeps a linear relationship with velocity if it is lower than 0.15 m/s, and with the increase of the velocity, a strong nonlinear relationship between the damping force and the velocity is observed. The available maximum damping force can be increased by decreasing the thickness of the conductor plate and the air gap, increasing the number of permanent magnets. There is an optimal location about the permanent magnets for the available maximum damping force. In addition, the hysteretic curves of the eddy current damping with rack and gear obtained from the test indicate that the ability of energy dissipation is considerable.

Research in Testing of Loess Foundation Pile Hysteretic Property under Horizontal Cyclic Load

2012 ◽  
Vol 433-440 ◽  
pp. 202-206
Author(s):  
Ming Bo Ding ◽  
Xing Chong Chen
Keyword(s):  
Cyclic Load ◽  
Large Scale ◽  
Damping Coefficient ◽  
Scale Model ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Loess Area ◽  
Hysteretic Property ◽  
Large Scale Model ◽  
Foundation Pile

In this paper, by the large scale model test of pile-soil in remodeling loess foundation, authors research the basic discipline of pile-soil interaction plastic hysteretic property of pile foundation in loess area under horizontal cyclic load and obtain hysteretic curves, skeleton curves and relationship between equivalent viscous damping coefficient and displacement under pile-soil interaction. The paper also discusses the intensity components, plastic and other energy and equivalent viscous damping coefficient cycles occur with varying degrees of degradation of the variation.

scholarly journals Study on Dynamic Characteristics of Aerostatic Bearing with Elastic Equalizing Pressure Groove

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Xiao-long Zhao ◽  
Hao Dong ◽  
Zhou Fang ◽  
Deng-di Chen ◽  
Jun-an Zhang
Keyword(s):  
Dynamic Characteristics ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Coupling Model ◽  
Damping Coefficient ◽  
Aerostatic Bearing ◽  
Equivalent Damping ◽  
New Type ◽  
Equivalent Damping Coefficient ◽  
Control Equation

Microvibration has an important influence on the dynamic performance of aerostatic bearings. Dynamic stiffness and equivalent damping coefficient are the main indexes to evaluate the dynamic characteristics of the aerostatic bearing. In order to study the dynamic characteristics of a new type of aerostatic bearing with the elastic equalizing pressure groove (EEPG), the dynamic characteristics of the new type of bearing are studied by theoretical calculation and experiment. First, the dynamic gas-solid coupling control equation is established. Then, the steady term and the perturbation term are decomposed by the perturbation method. By solving the coupling model, the dynamic characteristics of the bearing are calculated and analyzed. The calculation results show that the perturbation frequency has a significant effect on the dynamic stiffness and equivalent damping coefficient of the aerostatic bearing with EEPG. The dynamic stiffness increases with the increase of frequency, and the equivalent damping coefficient decreases with the increase of frequency. The experimental results are basically the same with the theoretical results, which effectively verify the correctness of the theoretical analysis.

scholarly journals Design analysis and performance evaluation of a novel Multi-Cantilever Foil Bearing

2021 ◽  
Vol 40 (3) ◽  
pp. 449-460
Author(s):  
M. Obaseki ◽  
P.T. Elijah ◽  
P.B. Alfred
Keyword(s):  
Performance Evaluation ◽  
Phase Angle ◽  
Design Analysis ◽  
Damping Coefficient ◽  
Viscous Damping ◽  
Maximum Deflection ◽  
Structural Stiffness ◽  
Equivalent Viscous Damping ◽  
Foil Bearing ◽  
And Performance

This study gives an explanation to design analysis and performance evaluation of a novel multi-cantilever foil bearing (MCFB). The aim of this study is to develop a theoretical model that will explain the working principles of the cantilever foil bearing. A theoretical derivation of structural and vibration models were developed to find structural stiffness, equivalent viscous damping and maximum deflection. Findings show that the theoretical results of structural models have an equivalent structural stiffness of 58.59kN/mm, equivalent viscous damping of 0.599kNs/m and maximum deflection of 0.5675mm. The equivalent viscous damping is computed at a near zero circumferential coordinate (0.0350). The results obtained from vibration models show an equivalent structural stiffness of 58.74kN/mm, equivalent viscous damping of 0.228kNs/m and maximum deflection of 0.5675mm. Theoretical viscous damping coefficient varies from 0.23kNs/m at 24Hz to 0.026kNs/m at 200Hz when determined at maximum deflection of 0.5675mm and phase angle of 0.0350. This means the higher the frequency, the lower the viscous damping coefficient. The validation was done over frequency range 24-200Hz and at amplitude of 50mm at a 450 phase angle. The models were found to have compared well with experimental results in the prediction of equivalent viscous damping coefficient. The models can be relied upon to analyze the behaviour of MCFB and it can also form a theoretical background for the design and manufacture of Multi-Cantilever Foil Bearing.

Force Behavior of Outer Annular-Stiffener Type Steel Castellated Beam-Concrete Filled Steel Tuber

2013 ◽  
Vol 405-408 ◽  
pp. 861-864
Author(s):  
Ming Li ◽  
Yong Liu ◽  
He Yuan
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Simulation Method ◽  
Damping Coefficient ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Type Steel ◽  
Dissipation Coefficient ◽  
Castellated Beam ◽  
Energy Dissipation Coefficient

The force behavior of outer annular-stiffener type steel castellated beam (OATSCB) - concrete filled steel tube (CFST) is analyzed, and the feasibility of this kind of join is discussed. The loading process of the joint is simulated by using finite element software. By analyzing the hysteretic loops, skeleton curves, energy dissipation coefficient, equivalent viscous damping coefficient and ductility coefficient, the bearing capacity and seismic performance of this type of joint is studied. Before simulation, the validity of the simulation method is verified by using the previous experiment data of outer annular-stiffener type steel beam (OATSB) - CFST. It shows that the results from the finite element simulation method and the experiment are similar to each other, and the hysteretic loops is plump , the energy dissipation coefficient, equivalent viscous damping coefficient and ductility coefficient of this type of joint are high. It can be seen that this type of joint has good mechanical properties, and is easy to realize the yield mechanism of strong column weak beam.

scholarly journals Research on the Vertical Vibration Characteristics of Hydraulic Screw Down System of Rolling Mill under Nonlinear Friction

Processes ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 792 ◽  
Author(s):  
Yongshun Zhang ◽  
Wanlu Jiang ◽  
Yong Zhu ◽  
Zhenbao Li
Keyword(s):  
Parameter Uncertainty ◽  
Rolling Mill ◽  
Pid Controller ◽  
Vertical Vibration ◽  
Damping Coefficient ◽  
Practical Significance ◽  
Nonlinear Friction ◽  
Equivalent Damping ◽  
Leakage Coefficient ◽  
Equivalent Damping Coefficient

The rolling mill with hydraulic system is widely used in the production of strip steel. For the problem of vertical vibration of the rolling mill, the effects of different equivalent damping coefficient, leakage coefficient, and proportional coefficient of the controller on the hydraulic screw down system of the rolling mill are studied, respectively. First, a vertical vibration model of a hydraulic screw down system was established, considering the nonlinear friction and parameter uncertainty of the press cylinder. Second, the correlation between different equivalent damping coefficient, internal leakage coefficient, proportional coefficient, vertical vibration was analyzed. The simulation results show that, in the closed-loop state, when Proportional-Integral-Derivative (PID) controller parameters are fixed, due to the change of the equivalent damping coefficient and internal leakage coefficient, the system will have parameter uncertainty, which may lead to the failure of the PID controller and the vertical vibration of the system. This study has theoretical and practical significance for analyzing the mechanism of vertical vibration of the rolling mill.

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