Quantifying damping coefficient and attenuation at different frequencies for graphene modified polyurethane by drop ball test

The present research work is a part of a project was a semi-active structural control technique using magneto-rheological damper has to be performed. Magneto-rheological dampers are an innovative class of semi-active devices that mesh well with the demands and constraints of seismic applications; this includes having very low power requirements and adaptability. A small stroke magneto-rheological damper was mathematically simulated and experimentally tested. The damper was subjected to periodic excitations of different amplitudes and frequencies at varying voltage. The damper was mathematically modeled using parametric Modified Bouc-Wen model of magneto-rheological damper in MATLAB/SIMULINK and the parameters of the model were set as per the prototype available. The variation of mechanical properties of magneto-rheological damper like damping coefficient and damping force with a change in amplitude, frequency and voltage were experimentally verified on INSTRON 8800 testing machine. It was observed that damping force produced by the damper depended on the frequency as well, in addition to the input voltage and amplitude of the excitation. While the damping coefficient (c) is independent of the frequency of excitation it varies with the amplitude of excitation and input voltage. The variation of the damping coefficient with amplitude and input voltage is linear and quadratic respectively. More ever the mathematical model simulated in MATLAB was in agreement with the experimental results obtained.

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Formation of Standing Waves in Radial Tires

Tire Science and Technology ◽

10.2346/1.2150982 ◽

1984 ◽

Vol 12 (1) ◽

pp. 44-63 ◽

Cited By ~ 8

Author(s):

Y. D. Kwon ◽

D. C. Prevorsek

Keyword(s):

High Speed ◽

Critical Speed ◽

Unit Length ◽

Standing Waves ◽

Rolling Resistance ◽

Damping Coefficient ◽

Circular Membrane ◽

Critical Speeds ◽

Steel Cord ◽

The Individual

Abstract Radial tires for automobiles were subjected to high speed rolling under load on a testing wheel to determine the critical speeds at which standing waves started to form. Tires of different makes had significantly different critical speeds. The damping coefficient and mass per unit length of the tire wall were measured and a correlation between these properties and the observed critical speed of standing wave formation was sought through use of a circular membrane model. As expected from the model, desirably high critical speed calls for a high damping coefficient and a low mass per unit length of the tire wall. The damping coefficient is particularly important. Surprisingly, those tire walls that were reinforced with steel cord had higher damping coefficients than did those reinforced with polymeric cord. Although the individual steel filaments are elastic, the interfilament friction is higher in the steel cords than in the polymeric cords. A steel-reinforced tire wall also has a higher density per unit length. The damping coefficient is directly related to the mechanical loss in cyclic deformation and, hence, to the rolling resistance of a tire. The study shows that, in principle, it is more difficult to design a tire that is both fuel-efficient and free from standing waves when steel cord is used than when polymeric cords are used.

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Method for Estimating the Damping Coefficient of Oscillation Dynamics in Networks

2019 20th Asia-Pacific Network Operations and Management Symposium (APNOMS) ◽

10.23919/apnoms.2019.8892949 ◽

2019 ◽

Author(s):

Shinichi Kikuchi ◽

Masaki Aida

Keyword(s):

Damping Coefficient ◽

Oscillation Dynamics

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Design of a Pendulum-type Anti-rolling System for USSV and Verification Based on Roll Damping Coefficient

Journal of the Society of Naval Architects of Korea ◽

10.3744/snak.2019.56.6.550 ◽

2019 ◽

Vol 56 (6) ◽

pp. 550-558

Author(s):

Woo-Seok Jin ◽

Yong-Ho Kim ◽

Jun-Ho Jung ◽

Kwangkook Lee ◽

Dong-Hun Kim

Keyword(s):

Damping Coefficient ◽

Roll Damping ◽

Rolling System

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Development of new 9-ball test protocols for assessing expertise in cue sports

BMC Sports Science Medicine and Rehabilitation ◽

10.1186/s13102-021-00237-9 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Jing Wen Pan ◽

John Komar ◽

Pui Wah Kong

Keyword(s):

Power Control ◽

Video Analysis ◽

Test Performance ◽

Absolute Error ◽

Group Differences ◽

Intra Class Correlation ◽

National Team ◽

Alignment Angle ◽

Overall Performance ◽

Ball Test

Abstract Background This study aimed to develop new test protocols for evaluating 9-ball expertise levels in cue sports players. Methods Thirty-one male 9-ball players at different playing levels were recruited (recreational group, n = 8; university team, n = 15; national team, n = 8). A 15-ball test was administered to indicate overall performance by counting the number of balls potted. Five skill tests (power control, cue alignment, angle, back spin, and top spin) were conducted to evaluate specific techniques by calculating error distances from pre-set targets using 2D video analysis. Results Intra-class correlation analyses revealed excellent intra-rater and inter-rater reliability in four out of five skill tests (ICC > 0.95). Significant between-group differences were found in 15-ball test performance (p < 0.001) and absolute error distances in the angle (p < 0.001), back spin (p = 0.006), and top spin tests (p = 0.045), with the recreational group performing worst while the national team performing best. Greater inter-trial variability was observed in recreational players than the more skilled players (p < 0.005). Conclusions In conclusion, the 9-ball test protocols were reliable and could successfully discriminate between different playing levels. Coaches and researchers may employ these protocols to identify errors, monitor training, and rank players.

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Filtering theory for a power system dynamics in the presence of stochastic damping coefficient

2020 IEEE Region 10 Symposium (TENSYMP) ◽

10.1109/tensymp50017.2020.9230651 ◽

2020 ◽

Author(s):

Ravish H. Hirpara ◽

Ravish H. Hirpara

Keyword(s):

Power System ◽

System Dynamics ◽

Damping Coefficient ◽

Filtering Theory ◽

Power System Dynamics

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Research and Implementation of an Automatic Reset Force of a Force Feedback Handle

MATEC Web of Conferences ◽

10.1051/matecconf/202031601003 ◽

2020 ◽

Vol 316 ◽

pp. 01003

Author(s):

Xin An Qiu ◽

Shi Jia Wang ◽

Dong Tao Ma

Keyword(s):

Force Feedback ◽

High Accuracy ◽

Damping Coefficient ◽

Robotic Arm ◽

Force Model ◽

Stiffness Coefficient ◽

Application Field ◽

New Development

Take the force feedback handle applied to the teleoperation of space robotic arm as a requirement. In order to improve users’ experience, we studied the automatic reset force of the handle. This paper proposes a springdamping model and applies it to the torque output of the motor to achieve a good reset of the handle, which is a new development of the application field of the automatic reset force model of the force feedback device. The experiment shows that the automatic reset force model has high accuracy when the handle returns to zero. In addition, through dynamic and reasonable adjustment of the stiffness coefficient and damping coefficient, it can meet the needs of different users for the automatic reset force of the force feedback handle.

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