A Numerical Method for Predicting the Dynamic Performance of Electromechanical Relays

1974 ◽  
Vol 41 (2) ◽  
pp. 360-362 ◽  
Author(s):  
G. L. Elliott
Keyword(s):  
Numerical Method ◽  
Dynamic Characteristics ◽  
Magnetic Circuit ◽  
Dynamic Performance ◽  
Equations Of Motion ◽  
Predicted Values ◽  
Electromagnetic Relays ◽  
Good Agreement

This paper describes a method for estimating the dynamic characteristics of electromagnetic relays. The equations of motion are formulated based on a constant core reluctance model magnetic circuit and then solved using an extended de Vogelaere method. Good agreement is found between the predicted values and those measured in practice.

Dynamic Characteristics of a Six-Bar Hinge Mechanism as Used in Cabinets

2004 ◽  
Author(s):  
Fu-Chen Chen
Keyword(s):  
Dynamic Characteristics ◽  
Equations Of Motion ◽  
Equation Of Motion ◽  
Simulation Results ◽  
Good Agreement

The dynamic characteristics of a six bar hinge mechanism as used in home cabinets were investigated using the method of equation of motion. The derived equations of motion were numerically solved and the motion of the hinge mechanism was simulated. The influence of mass and width of the cabinet door on the dynamic characteristics of the hinge mechanism as well as the effect of the hinge number on the force applied on the handle were also investigated. The experimental and simulation results showed good agreement with an error of under 2%, which validated the simulation results. The proposed approach can be used by hinge manufacturers for the design and analysis of similar hinge mechanisms.

Dynamic characteristics of planar linear array deployable structure based on scissor-like element with joint clearance using a new mixed contact force model

2016 ◽  
Vol 230 (18) ◽  
pp. 3161-3174 ◽  
Author(s):  
Bo Li ◽  
San-Min Wang ◽  
Ru Yuan ◽  
Xiang-Zhen Xue ◽  
Chang-Jian Zhi
Keyword(s):  
Contact Force ◽  
Dynamic Characteristics ◽  
Dynamic Performance ◽  
Equations Of Motion ◽  
Contact Model ◽  
Joint Clearance ◽  
Force Model ◽  
Continuous Contact ◽  
Deployable Structure ◽  
Contact Force Model

This paper aims at investigating precisely the dynamic performance of deployable structure constituted by scissor unit mechanisms with clearance joint. Based on the motion law in real joints, the contact model is established using an improved Gonthier nonlinear continuous contact force model, and the friction effect is considered using LuGre model. Moreover, the resulting contact force is suitable to be included into the generalized force of the equations of motion of a multibody system and contributes to replace motion constraints. In the sequel of this process, the effect of joint clearance is successfully introduced into the dynamical model of scissor deployable structure and the dynamic characteristics of deployable structure with joint clearance are obtained using a direct default correction method, which can directly modify the coordinates and speed of the system to avoid the numerical results divergence. Also, the new hybrid contact force model of revolute joint clearance is verified through comparing with the original model. The numerical simulation results show that the improved contact model proposed here has the great merit that predicts the dynamic behavior of scissor deployable structure with joint clearance.

scholarly journals SUCCESSIVE SALTATION OF A SAND GRAIN BY WIND

1970 ◽  
Vol 1 (12) ◽  
pp. 87 ◽  
Author(s):  
Yoshito Tsuchiya
Keyword(s):  
Dynamic Characteristics ◽  
Theoretical Approach ◽  
Equations Of Motion ◽  
Sand Transport ◽  
Granular Bed ◽  
Water Stream ◽  
Fixed Granular Bed ◽  
Good Agreement

In order to establish the mechanics of sand transport in an air or water stream, the mechanics of saltation of sand grains should first be considered In sand storms, most of the saltating sand grains on a granular bed have successively continued the saltation motion In this paper, such a saltation motion is defined as successive saltation A theoretical approach to the saltation of a single sand grain on a fixed granular bed is proposed on the basis of the equations of motion for the saltation and the dynamic characteristics of collision between a saltating sand grain and bed sand grains Some experiments of the successive saltation of a single sand gram on a fixed granular bed were carried out to compare with the theoretical relationships It was verified from the comparison that the theoretical relationships of the height and distance of saltation of a sand gram are in fairly good agreement m substance with the results of experiment.

scholarly journals Seasonal Estimates and Uncertainties of Snow Accumulation from CloudSat Precipitation Retrievals

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 363
Author(s):  
George Duffy ◽  
Fraser King ◽  
Ralf Bennartz ◽  
Christopher G. Fletcher
Keyword(s):  
Time Scales ◽  
Snow Water Equivalent ◽  
Spatial Scales ◽  
Snow Accumulation ◽  
High Latitudes ◽  
Percentage Points ◽  
Snow Water ◽  
Time Periods ◽  
Predicted Values ◽  
Good Agreement

CloudSat is often the only measurement of snowfall rate available at high latitudes, making it a valuable tool for understanding snow climatology. The capability of CloudSat to provide information on seasonal and subseasonal time scales, however, has yet to be explored. In this study, we use subsampled reanalysis estimates to predict the uncertainties of CloudSat snow water equivalent (SWE) accumulation measurements at various space and time resolutions. An idealized/simulated subsampling model predicts that CloudSat may provide seasonal SWE estimates with median percent errors below 50% at spatial scales as small as 2° × 2°. By converting these predictions to percent differences, we can evaluate CloudSat snowfall accumulations against a blend of gridded SWE measurements during frozen time periods. Our predictions are in good agreement with results. The 25th, 50th, and 75th percentiles of the percent differences between the two measurements all match predicted values within eight percentage points. We interpret these results to suggest that CloudSat snowfall estimates are in sufficient agreement with other, thoroughly vetted, gridded SWE products. This implies that CloudSat may provide useful estimates of snow accumulation over remote regions within seasonal time scales.

Dynamics Characteristics for Contact Surface of Machine Tool

2014 ◽  
Vol 538 ◽  
pp. 91-94
Author(s):  
Wei Ping Luo
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristics ◽  
Contact Surface ◽  
Dynamic Performance ◽  
Virtual Prototype ◽  
Prototype Model ◽  
Ansys Software ◽  
Dynamic Analyses ◽  
Contact Surfaces

A virtual prototype model of Machine Tool has been constructed by using the Pro/E software and the ANSYS software. Considering the effects of contact surfaces, dynamic analyses of Machine Tool are studied. The effects of contact surfaces on the dynamic characteristics of machine tool are studied. So that the purpose predicting and evaluating synthetically the machine tool dynamic performance without a physical sample can be achieved.

Analysis and Optimization of the Static and Dynamic Characteristics of Head Frame

2011 ◽  
Vol 418-420 ◽  
pp. 2055-2059 ◽  
Author(s):  
Yu Lin Wang ◽  
Na Jin ◽  
Kai Liao ◽  
Rui Jin Guo ◽  
Hu Tian Feng
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristics ◽  
Maximum Stress ◽  
Dynamic Performance ◽  
Mode Shapes ◽  
Cnc Machine ◽  
Static And Dynamic Characteristics ◽  
Maximum Deformation ◽  
Improvement Measures ◽  
Optimal Measure

The head frame is a key component which plays a supportive and accommodative role in the spindle system of CNC machine tool. Improving the static and dynamic characteristics has profound significance to the development of machine tool and product performance. The simplified finite element modal is established with ANSYS to carry out the static and modal analysis. The results showed that the maximum deformation of the head frame was 0.0066mm, the maximum stress was 3.94Mpa, the deformation of most region was no more than 0.0007mm, which all verified that the head frame had a good stiffness and deforming resistance; several improvement measures for dynamic performance were also proposed by analyzing the mode shapes, and the 1st order natural frequency increased 7.33% while the head frame mass only increased 1.58% applying the optimal measure, which improved the dynamic characteristics of the head frame effectively.

Modeling the Climber Fall Arrest Dynamics

2005 ◽  
Author(s):  
Lionel Manin ◽  
Jarir Mahfoudh ◽  
Matthieu Richard ◽  
David Jauffres
Keyword(s):  
Dynamic Characteristics ◽  
Equations Of Motion ◽  
Close Approximation ◽  
Non Linear ◽  
The Future ◽  
Safety Recommendations ◽  
Improved Design ◽  
Fall Arrest

Sports and mountaineering activities are becoming more and more popular. Equipment constructors seek to develop products and devices that are easy to use and that take into account all safety recommendations. PETZL and INSA have collaborated to develop a model for the simulation of displacements and efforts involved during the fall of a climber in the “safety chain”. The model is based on the classical equations of motion, in which climber and belayer are considered as rigid masses, while the rope is considered as a series of non-linear stiffness passing through several devices as brakes and runners. The main goal is to predict the forces in the rope and on the return anchor at the first rebound of the fall. Experiments were first performed in order to observe and determine the dynamic characteristics of the rope, and then to validate results stemming from simulations. Several fall configurations are simulated, and the model performs satisfactorily. It also provides a close approximation of the phenomena observed experimentally. The model enables the assessment of the existing equipments and the improved design of the future one.

Failure Mechanism Analysis of Electromagnetic Relay under Mechanical Impact

2013 ◽  
Vol 473 ◽  
pp. 39-45 ◽  
Author(s):  
Guo Wei Zhao ◽  
Yong Chen ◽  
De Yong Li ◽  
Bin Tang
Keyword(s):  
Failure Mechanism ◽  
Magnetic Circuit ◽  
Impact Damage ◽  
Engineering Application ◽  
Air Gap ◽  
Mechanism Analysis ◽  
Mechanical Impact ◽  
Electromagnetic Relay ◽  
Electromagnetic Relays ◽  
The Impact

The aim was to analyze failure mechanism of electromagnetic relay caused by mechanical impact. The principle of electromagnetic relays was studied and the effect of mechanical impact on electromagnetic relays was analyzed in this paper. Based on the established magnetic circuit model, the relationship of the magnetic field strength, the electromagnetic attraction and the impact damage degree was studied. Then, the damage intensity of mechanical impact on magnetic circuit was decided. Afterwards, the structure of electromagnetic relays was improved, and the mechanical impact simulation was studied by ANSYS. The results show that the uncontrollability of electromagnetic relay is mainly caused by air gap, which is aroused by mechanical impact; in addition, the size of air gap is inversely proportional to electromagnetic attraction force. Moreover, the improved structure of relays can increase impact resistance and broaden the scope of engineering application of electromagnetic relay.

Investigation of Sensitivity Effect Based on Mass and Stiffness Modification in Automobile Crankshaft

2015 ◽  
Vol 752-753 ◽  
pp. 839-844
Author(s):  
R.M.S. Zetty ◽  
B.A. Aminudin ◽  
L.M. Aung ◽  
M.K. Khalid ◽  
H.M.Y. Norfazrina ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Natural Frequency ◽  
Dynamic Characteristics ◽  
Differential Analysis ◽  
Partial Differential ◽  
Mechanical Parts ◽  
Stiffness Reduction ◽  
Experiment And Simulation ◽  
Good Agreement

A modeling through sensitivity analysis is one of the promising methods to investigate the dynamic characteristics of complex mechanical parts. This study aimed to investigate the effect of sensitivity based on mass and stiffness modification in automobile crankshaft as a function of natural frequency. Verification for the crankshaft model that is used in the experiment and simulation was done and both results showed good agreement and small errors percentage. The modification was also done by reducing the different percentage of crankshaft’s mass and stiffness. Partial differential analysis was used in the sensitivity analysis in order to figure out the natural frequency after every set of modification. According to the results, we also found that there were changes of sensitivity value by changes in mass value but the stiffness value remains unchanged. However, there is no significant effect of stiffness reduction on vibration was found in this research.

An Integrated Joint Dynamics System for Elastically Jointed Structures

1991 ◽  
Author(s):  
Y. Rong ◽  
H. S. Tzou
Keyword(s):  
Dynamic Characteristics ◽  
Dynamic Performance ◽  
Measuring Device ◽  
Joint Friction ◽  
Vibration Data ◽  
Unit Structure ◽  
Joint Dynamics ◽  
Joint Clearances ◽  
Stochastic Simulator ◽  
Vibration Measuring

Abstract The dynamic behavior of elastic joints strongly affect the dynamic performance of a jointed mechanical system. The dynamic contacts introduced by joint clearances create a system with nonlinear characteristics. Special effort needs to be made to study jointed mechanical systems. This paper presents an integrated joint dynamics system, which can be used to predict the dynamic characteristics of a newly designed structure, or to analyze an existing jointed structure. This joint dynamics system can also be applied as a real time monitoring and diagnosis system when it is connected with a vibration measuring device. The joint dynamics system includes: 1) a theoretical model of jointed structures, in which the joint clearance and joint friction effects are considered; 2) a stochastic simulator which is used to generate vibration data and evaluate system dynamic characteristics; 3) a diagnostic monitoring algorithm for vibration state detection; and 4) a forecasting vibration control scheme. The joint dynamics system is applied to the dynamic analysis of a truss-cell unit structure. The results presented in this paper show that the joint dynamics system is effective.

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