A Design Method for Reducing the Effects of Clearances at Revolute Joints

1985 ◽  
Vol 199 (2) ◽  
pp. 153-158 ◽  
Author(s):  
J K Shin ◽  
B M Kwak
Keyword(s):  
General Theory ◽  
Empirical Formula ◽  
Design Method ◽  
Mechanical Energy ◽  
Clearance Joints ◽  
Revolute Joints ◽  
Non Linear ◽  
Linear Spring ◽  
Crank Mechanism ◽  
Kinematic Properties

A method for designing a mechanism which is free of contact loss in clearance connections is developed. Only revolute joints are considered as possible clearance joints. Earles and Wu's empirical formula has been used for defining a perfect joint or contact loss free joint. A general theory for conditions of a perfect joint has been derived in terms of the mechanical energy and the kinematic properties of the joint. This general theory was applied to a slider crank mechanism and it was shown that designing a perfect joint is theoretically possible through balancing by a non-linear spring. Further it was shown that this technique gives a practical guide for balancing a mechanism with linear springs to reduce the possibility of contact loss in clearance joints.

Analysis of the Dynamic Behavioral Performance of Mechanical Systems With Multi–Clearance Joints

2011 ◽  
Vol 7 (1) ◽  
Author(s):  
S.M. Megahed ◽  
A.F. Haroun
Keyword(s):  
Impact Force ◽  
Dynamic Performance ◽  
Mechanical Systems ◽  
Behavioral Performance ◽  
Clearance Joints ◽  
Revolute Joints ◽  
Clearance Joint ◽  
Computation Algorithm ◽  
Maximum Impact Force ◽  
Crank Mechanism

In this investigation, the effect of revolute joints’ clearance on the dynamic performance of mechanical systems is reported. A computation algorithm is developed with the aid of SolidWorks/CosmosMotion software package. A slider-crank mechanism with one and two clearance-joints is studied and analyzed when working in vertical and in horizontal planes. The simulation results point out that the presence of such clearance in the joints of the system understudy leads to high peaks in the characteristic curves of its kinematic and dynamic performance. For a multiclearance joints mechanism, the maximum impact force at its joints takes its highest value at the nearest joint to the input link. This study also shows that, when the mechanism works in horizontal plane, the rate of impacts at each clearance-joint increases and consequently the clearance-joints and actuators will deteriorate faster.

Wear Analysis of Two Revolute Joints With Clearance in Multibody Systems

2016 ◽  
Vol 11 (1) ◽  
Author(s):  
Pei Li ◽  
Wei Chen ◽  
Desheng Li ◽  
Rufei Yu ◽  
Wenjing Zhang
Keyword(s):  
Dynamic Analysis ◽  
Multibody Systems ◽  
Mechanical Systems ◽  
Clearance Joints ◽  
Revolute Joints ◽  
Wear Analysis ◽  
Coupling Dynamics ◽  
System Life ◽  
Crank Mechanism

The wear of multiple joints with clearance is one of the main impacts on the life of mechanical systems while very limited study has been done on this subject. To be different with many existed researches focused on the dynamic analysis of multibody systems with multiple clearance joints, the wear of two revolute joints with clearance in multibody systems is analyzed in this paper by coupling dynamics with tribology. Based on a planar slider crank mechanism with two clearance joints, it is observed that the clearance sizes nonlinearly influence the wear depths of the two joints with clearance. Meanwhile, an appropriate relationship between the two joints' clearance sizes can significantly decrease the wear of the joints, which would greatly improve the system life. Both the independent and interactive influences of the two joints with clearances on the wear are investigated in this paper. The relation equations of the two clearances obtained in this work will significantly decrease the wear of the two clearance joints.

scholarly journals Perturbations of nonlinear autonomous oscillators

1994 ◽  
Vol 35 (4) ◽  
pp. 445-468 ◽  
Author(s):  
P. B. Chapman
Keyword(s):  
General Theory ◽  
Fourier Coefficients ◽  
Multiple Scales ◽  
Second Order ◽  
Multiple Scales Method ◽  
Suitable Parameter ◽  
Non Linear

AbstractA general theory is given for autonomous perturbations of non-linear autonomous second order oscillators. It is found using a multiple scales method. A central part of it requires computation of Fourier coefficients for representation of the underlying oscillations, and these coefficients are found as convergent expansions in a suitable parameter.

A shallow-liquid theory in magnetohydrodynamics

1960 ◽  
Vol 7 (1) ◽  
pp. 81-107 ◽  
Author(s):  
L. E. Fraenkel
Keyword(s):  
Magnetic Field ◽  
Mechanical Energy ◽  
Fluid Velocity ◽  
Linear Equations ◽  
Qualitative Difference ◽  
Meridional Plane ◽  
Plane Flow ◽  
Non Linear ◽  
Moderate Magnetic Field ◽  
Approximate Equations

The non-linear and linear ‘shallow-water’ theories, which describe long gravity waves on the free surface of an inviscid liquid, are extended to the case of an electrically conducting liquid on a horizontal bottom, in the presence of a vertical magnetic field. The dish holding the liquid, and the medium outside it, are assumed to be non-conducting. The approximate equations are based on a small ratio of depth to wavelength, on the properties of mercury, and on a moderate magnetic field strength. These equations have a ‘magneto-hydraulic’ character, for in the shallow liquid layer the horizontal fluid velocity and current density are independent of the vertical co-ordinate.Some explicit solutions of the linear equations are obtained for plane flows and for axi-symmetric flows in which the velocity vector lies in a vertical, meridional plane. The amplitudes of waves in a dish, and the amplitudes behind wave fronts progressing into undisturbed liquid, are found to be exponentially damped, the mechanical energy associated with a disturbance being dissipated by Joule heating.The approximate non-linear equations for plane flow are studied by means of characteristic variables, and it appears that, because of the magnetic damping effect, there is less qualitative difference between solutions of the non-linear and linear approximate equations at large times than is the case when the magnetic field is absent. In particular, the characteristic curves depart only a finite distance from their ‘undisturbed positions’.

Non-linear spring model for backfill grout-consolidation behind shield tunnel lining

2021 ◽  
Vol 136 ◽  
pp. 104235
Author(s):  
Xiao-Xue Liu ◽  
Shui-Long Shen ◽  
Ye-Shuang Xu ◽  
Annan Zhou
Keyword(s):  
Tunnel Lining ◽  
Shield Tunnel ◽  
Spring Model ◽  
Non Linear ◽  
Linear Spring

scholarly journals Dynamic Response Analysis of Planar Multilink Mechanism considering Wear in Clearances

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Shuai Jiang ◽  
Xiulong Chen ◽  
Yu Deng
Keyword(s):  
Theoretical Basis ◽  
Dynamic Responses ◽  
Response Analysis ◽  
Nonlinear Characteristics ◽  
Wear Prediction ◽  
Normal Contact ◽  
Normal Contact Force ◽  
Clearance Joints ◽  
Revolute Joints ◽  
Analysis Of Dynamics

Clearance wear is one of the factors that affects dynamics for mechanical systems. A numerical methodology suitable for modeling and calculation of wear at multiple revolute clearance pairs in the field of the planar multilink mechanism is proposed. In this paper, the 2-DOF nine-bar mechanism considering two revolute clearance joints is regarded as the study object. Normal contact force and friction force models of revolute clearance joints used Lankarani–Nikravesh (L-N) and LuGre models, respectively. The iterative wear prediction process based upon Archard’s model has been applied to calculate wear characteristics. The wear prediction procedure is integrated with multibody dynamics, wear depths at revolute clearance joints are calculated, and the surface of shaft and bearing is reconstructed twice. The dynamic responses of mechanism considering two nonregular revolute clearances caused by wear are studied in depth. The nonlinear characteristics of the mechanism after wear are studied by the phase diagram and Poincaré map. Influences of different initial constant clearance values and different driving speeds on wear of two revolute joints are also researched. The results show that it is necessary to consider the factor of irregular clearances caused by wear in analysis of dynamics of precision mechanisms. Initial constant clearance values and driving speeds have some influence on wear phenomenon. This research provides a theoretical basis for studying dynamics of the planar multilink mechanism considering wear in multiple clearances.

scholarly journals Multi-physics phenomena influencing the performance of the car horn

2019 ◽  
Vol 38 (2) ◽  
pp. 544-557 ◽  
Author(s):  
Cristian Medè ◽  
Alberto Doria ◽  
Paolo Munaretto ◽  
Jorge SG Valdecasas
Keyword(s):  
Numerical Simulations ◽  
Mechanical Energy ◽  
Input Voltage ◽  
Harmonic Excitation ◽  
Electromagnetic Energy ◽  
Electrical Parameters ◽  
Detailed Model ◽  
Non Linear ◽  
Linear Effects ◽  
Car Horn

Usually cars are equipped with disk horns. In these devices electromagnetic energy is converted into mechanical energy of two nuclei that vibrate and impact each other – the impacts excite the disk that radiates sound. This paper aims at understanding the results of acoustic tests carried out on horns with different excitation voltages and different mounting brackets. Since many non-linear phenomena are inherent in the vibrations of the nuclei, a detailed model of the electromechanical system is developed. Results show the dependence of operating frequency on the input voltage and the role played by the various mechanical and electrical parameters on the dynamics of the horn. Particular non-linear effects, like sub-harmonic excitation, are presented and discussed. A general agreement between experimental results and numerical simulations is found.

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