Viscous damping force during head-on collision of two spherical particles

2011 ◽  
Vol 23 (1) ◽  
pp. 013305 ◽  
Author(s):  
J. S. Marshall
Keyword(s):  
Spherical Particles ◽  
Viscous Damping ◽  
Damping Force

Damping characteristics of a magneto-rheological damper with dual independent controllable ducts

2021 ◽  
pp. 1045389X2110188
Author(s):  
Jianqiang Yu ◽  
Xiaomin Dong ◽  
Tao Wang ◽  
Zhengmu Zhou ◽  
Yaqin Zhou
Keyword(s):  
Dynamic Range ◽  
Fluid Flows ◽  
Mr Damper ◽  
Viscous Damping ◽  
The Novel ◽  
The Finite Element Method ◽  
Damping Force ◽  
Damping Characteristics ◽  
Magneto Rheological ◽  
The Mathematical Model

This paper presents the damping characteristics of a linear magneto-rheological (MR) damper with dual controllable ducts based on numerical and experimental analysis. The novel MR damper consisting of a dual-rod cylinder system and a MR valve is used to reduce the influences of viscous damping force and improve dynamic range. Driven by the dual-rod cylinder system, MR fluid flows in the MR valve. The pressure drop of the MR valve with dual independent controllable ducts can be controlled by tuning the current of two independent coils. Based on the mathematical model and the finite element method, the damping characteristics of the MR damper is simulated. A prototype is designed and tested on MTS machine to evaluate its damping characteristics. The results show that the working states and damping force of the MR damper can be controlled by the two independent coils.

High Efficient Viscoelastic Damper for Heavy Trucks

2012 ◽  
Vol 215-216 ◽  
pp. 318-321 ◽  
Author(s):  
Sai Fei Zhang ◽  
Xiao Ling Liu ◽  
Yong Liu
Keyword(s):  
Flow Rate ◽  
Viscous Damping ◽  
Calculation Formula ◽  
Performance Curve ◽  
Test Results ◽  
Viscoelastic Damper ◽  
Damping Force ◽  
Heavy Trucks ◽  
High Efficient ◽  
Damper Design

In this paper, a new viscoelastic damper design for heavy trucks is presented and a calculation formula of viscous damping force considering the effect of Viscoelastic Fluids (VF) flow rate is carried out. By numerically simulating this equation, curves of the viscoelastic damper performance curve is obtained, and the results show that theoretical calculation result and the test results are well consistent, with the exception at the start point. Theoretical curves are more plumpness in compared with test curves.

Dynamic Motion Analysis of Plane Mechanisms With Coulomb and Viscous Damping via the Joint Force Analysis

1975 ◽  
Vol 97 (2) ◽  
pp. 551-560 ◽  
Author(s):  
Cemil Bagci
Keyword(s):  
Dynamic Equilibrium ◽  
Viscous Damping ◽  
Force Analysis ◽  
Initial Value ◽  
Damping Force ◽  
Joint Force ◽  
Coulomb Damping ◽  
Dynamic Motion ◽  
Joint Forces ◽  
Input Torque

Analysis of response of determinate plane mechanisms to known driving input force, or input torque, via the joint force analysis is presented. Coulomb damping and viscous damping forces in the pair bearings are included. Equations of dynamic equilibrium are solved for the components of the normal joint forces and for the motion of the mechanism as initial-value problems. The rotation of the resultant joint force, due to the fact that the pair member on a link is the inner member or the outer member of the pair, is considered by defining a generalized Coulomb damping force. Links of the mechanisms are considered rigid. The plane 4R and slider-crank switch mechanisms are investigated. Explicit solutions and numerical examples are given.

scholarly journals Damping Force and Loading Position Dependence of Mass Sensitivity of Magnetoelastic Biosensors in Viscous Liquid

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 67
Author(s):  
Kewei Zhang ◽  
Zhe Chen ◽  
Qianke Zhu ◽  
Yong Jiang ◽  
Wenfeng Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Damping Coefficient ◽  
Viscous Damping ◽  
Simulation Approach ◽  
Damping Force ◽  
Mass Sensitivity ◽  
High Order Resonance ◽  
Target Loading ◽  
Position Dependence ◽  
Different Order

We established the vibration governing equation for a magnetoelastic (ME) biosensor with target loading in liquid. Based on the equation, a numerical simulation approach was used to determine the effect of the target loading position and viscous damping coefficient on the node (“blind points”) and mass sensitivity (Sm) of an ME biosensor under different order resonances. The results indicate that viscous damping force causes the specific nodes shift but does not affect the overall variation trend of Sm as the change of target loading position and the effect on Sm gradually reduces when the target approaches to the node. In addition, Sm decreases with the increase of viscous damping coefficient but the tendency becomes weak at high-order resonance. Moreover, the effect of target loading position on Sm decreases with the increase of viscous damping coefficient. Finally, the results provide certain guidance on improving the mass sensitivity of an ME biosensor in liquid by controlling the target loading position.

An Advanced Test Method to Determine Viscous Damping of Floating Structures

2010 ◽  
Author(s):  
Z. J. Huang ◽  
B. J. O’Donnell ◽  
T. W. Yung ◽  
S. T. Slocum
Keyword(s):  
Low Frequency ◽  
Test Method ◽  
Total Force ◽  
Viscous Damping ◽  
Damping Force ◽  
Restoring Force ◽  
Viscous Forces ◽  
Motion Time ◽  
Research Company ◽  
Time Histories

ExxonMobil Upstream Research Company developed an advanced model test method to determine reliable damping values for predicting low frequency motions of an FLNG barge and an LNG carrier. Since viscous damping forces are a very small portion of the total force on the model, how to separate the viscous forces from the total forces is the key technical challenge. To better isolate viscous damping forces, an inertial compensation system consisting of springs was employed in the test. The spring stiffness was designed such that the restoring force cancelled the large inertial loads at the oscillation frequency. Furthermore, double-body models were built and were deeply submerged to minimize surface wave damping. With such an experimental setup, the total force measured was mainly the viscous damping force. Viscous damping was derived from the measured force and motion time histories.

Determination of Viscous Damping for Low Frequency Motions of Floating Structures

2011 ◽  
Author(s):  
Z. J. Huang ◽  
B. J. O’Donnell ◽  
T. W. Yung ◽  
S. T. Slocum
Keyword(s):  
Forced Oscillation ◽  
Low Frequency ◽  
Test Method ◽  
Irregular Waves ◽  
Viscous Damping ◽  
Damping Force ◽  
Near Resonance ◽  
Research Company ◽  
Decay Tests ◽  
Scale Motion

ExxonMobil Upstream Research Company developed an advanced model test method to determine reliable damping values for predicting low frequency motions of an FLNG barge and an LNG carrier [1]. An inertial compensation system was introduced in the test to confidently isolate the relatively very small viscous damping force from the total measured forces in the forced oscillation tests. In the system, the spring stiffness in the restoring mechanism was tuned such that the test was done near resonance. This method has been successfully applied to ExxonMobil forced oscillation tests to measure damping of deeply submerged, double body models. Three types of motions were generated in the tests: sinusoidal motions, decay motions and motions with multiple frequencies. In this paper, the authors attempt to correlate the damping obtained from decay tests and from tests with motions of multiple frequency components. Findings from this work help determine damping for predictions of full scale motion in irregular waves.

scholarly journals Modeling and Analysis of a SiC Microstructure-Based Capacitive Micro-Accelerometer

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6222
Author(s):  
Xiang Tian ◽  
Wei Sheng ◽  
Zhanshe Guo ◽  
Weiwei Xing ◽  
Runze Tang
Keyword(s):  
Low Frequency ◽  
Superior Performance ◽  
Viscous Damping ◽  
Damping Force ◽  
Modeling And Analysis ◽  
Time Frequency ◽  
Capacitive Accelerometer ◽  
Silicon Devices ◽  
Main Components ◽  
Inertial Measurements

In this study, a comb-type capacitive accelerometer based on a silicon carbide (SiC) microstructure is presented and investigated by the finite element method (FEM). It has the advantages of low weight, small volume, and low cross-coupling. Compared with silicon(111) accelerometers with the same structure, it has a higher natural frequency. When the accelerometer vibrates, its resistive force consists of two main components: a viscous damping and an elastic damping force. It was found that viscous damping dominates at low frequency, and elastic damping dominates at high frequency. The second-order linear system of the accelerometer was analyzed in the time-frequency domain, and its dynamic characteristics were best when the gap between the capacitive plates was 1.23 μm. The range of this accelerometer was 0–100 g, which is 1.64 times that of a silicon(111) accelerometer with the same structure. In addition, the accelerometer could work normally at temperatures of up to 1200 °C, which is much higher than the working temperatures of silicon devices. Therefore, the proposed accelerometer showed superior performance compared to conventional silicon-based sensors for inertial measurements.

scholarly journals Wall Properties and Slip Consequences on Peristaltic Transport of a Casson Liquid in a Flexible Channel with Heat Transfer

2018 ◽  
Vol 3 (1) ◽  
pp. 277-290 ◽  
Author(s):  
P. Devaki ◽  
S. Sreenadh ◽  
K. Vajravelu ◽  
K. V. Prasad ◽  
Hanumesh Vaidya
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Wave Propagation ◽  
Peristaltic Flow ◽  
Physical Parameters ◽  
Viscous Damping ◽  
Damping Force ◽  
Long Wavelength ◽  
Wall Properties ◽  
The Impact

AbstractIn this paper, the peristaltic wave propagation of a Non-Newtonian Casson liquid in a non-uniform (flexible)channel with wall properties and heat transfer is analyzed. Long wavelength and low Reynolds number approximations are considered. Analytical solution for velocity, stream function and temperature in terms of various physical parameters is obtained. The impact of yield stress, elasticity, slip and non-uniformity parameters on the peristaltic flow of Casson liquidare observed through graphs and discussed. The important outcome is that an increase in rigidity, stiffness and viscous damping force of the wall results in the enhancement of the size and number of bolus formed in the flow pattern.

A Method for Extracting Building Empirical Capacity Curves from Earthquake Response Data

2016 ◽  
Vol 32 (4) ◽  
pp. 2229-2244 ◽  
Author(s):  
Jeffrey Dowgala ◽  
Ayhan Irfanoglu
Keyword(s):  
Small Scale ◽  
Earthquake Response ◽  
Viscous Damping ◽  
Acceleration Response ◽  
Damping Force ◽  
Restoring Force ◽  
Equivalent Viscous Damping ◽  
Strong Base ◽  
Capacity Curves ◽  
Response Data

A method is presented for extracting empirical capacity curves from building earthquake response data. The method can be applied to buildings with acceleration response records from each floor to develop story empirical capacity curves assuming the building has flexible columns and rigid floors. The method can also be applied to buildings with acceleration response records from the roof and ground to develop a fundamental mode empirical capacity curve. The method relies on extracting the restoring force and relative displacement of the system by removing damping force, considered as equivalent viscous damping, from the inertial response, using a proposed viscous damping identification procedure. The method is demonstrated using data from a small-scale, three-story experimental model subjected to strong base motion.

A Framework to Determine the Upper Bound on Extractable Power as a Function of Input Vibration Parameters

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
John D. Heit ◽  
Shad Roundy
Keyword(s):  
Upper Bound ◽  
Time Dependent ◽  
Mathematical Framework ◽  
Vibration Source ◽  
Viscous Damping ◽  
Damping Force ◽  
Dependent Frequency ◽  
Sinusoidal Input ◽  
Linear Spring ◽  
Vibration Parameters

AbstractThis paper outlines a mathematical framework to determine the upper bound on extractable power as a function of the forcing vibrations. In addition, the method described provides insight into the dynamic transducer forces required to attain the upper bound. The relationship between vibration parameters and transducer force gives a critical first step in determining the optimal transducer architecture for a given vibration source. The method developed is applied to three specific vibration inputs: a single sinusoid, the sum of two sinusoids, and a single sinusoid with a time-dependent frequency. As expected, for the single sinusoidal case, the optimal transducer force is found to be that produced by a resonant linear spring and a viscous damping force, with matched impedance to the mechanical damper. The resulting transducer force for the input described by a sum of two sinusoids is found to be inherently time dependent. The upper bound on power output is shown to be twice that obtainable from a linear harvester centered at the lower of the two frequencies. Finally, the optimal transducer force for a sinusoidal input with a time-dependent frequency is characterized by a viscous damping term and a linear spring with a time-dependent coefficient.

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