The Linear Approximated Equation of Vibration for a Pair of Spur Gears: Theory and Experiment

1992 ◽  
Author(s):  
Yurong Cai ◽  
Teru Hayashi
Keyword(s):  
Analytical Solution ◽  
Nonlinear Equation ◽  
Linear Equation ◽  
Static Load ◽  
Time Varying ◽  
Spur Gears ◽  
Contact Ratio ◽  
Profile Error ◽  
Rotational Vibration ◽  
Set Up

Abstract The nonlinear equation for the rotational vibration of a pair of spur gears has a restriction that the analytical solution of the equation cannot be obtained. In this paper, the linear equation of vibration is derived theoretically and its physical model, i.e. the linear model of vibration is presented. The analytical solution of the linear equation, which is derived by analytical method, agrees well with the numerically calculated result by the nonlinear equation. By analyzing the analytical solution of the linear equation in detail, we clarified the relation between the waveforms of the vibration and the profile error of gear pairs, and also found that the effect of the contact ratio to the vibration is large and complex. The equivalent error, accounting for effects of the static load, the time-varying stiffness and the profile error of gear pairs, is proposed in this paper. It can be considered as promising for evaluating the profile error, because the vibration of gear pairs is excited mainly by the equivalent error. Finally, for confirming the above results, the vibration of two tested gear pairs has been measured by an experimental set-up for this purpose.

The Linear Approximated Equation of Vibration of a Pair of Spur Gears (Theory and Experiment)

1994 ◽  
Vol 116 (2) ◽  
pp. 558-564 ◽  
Author(s):  
Y. Cai ◽  
T. Hayashi
Keyword(s):  
Analytical Solution ◽  
Nonlinear Equation ◽  
Linear Equation ◽  
Static Load ◽  
Time Varying ◽  
Spur Gears ◽  
Contact Ratio ◽  
Profile Error ◽  
Rotational Vibration ◽  
Set Up

The nonlinear equation for the rotational vibration of a pair of spur gears has a restriction that the analytical solution of the equation cannot be obtained. In this paper, the linear equation of vibration is derived theoretically and its physical model, i.e., the linear model of vibration is presented. The analytical solution of the linear equation, which is derived by analytical method, agrees well with the numerically calculated result by the nonlinear equation. By analyzing the analytical solution of the linear equation in detail, we clarified the relation between the waveforms of the vibration and the profile error of gear pairs, and also found that the effect of the contact ratio to the vibration is large and complex. The equivalent error, accounting for effects of the static load, the time-varying stiffness, and the profile error of gear pairs, is proposed in this paper. It can be considered as promising for evaluating the profile error, because the vibration of gear pairs is excited mainly by the equivalent error. Finally, for confirming the above results, the vibration of two tested gear pairs has been measured by an experimental set-up for this purpose.

The Optimum Modification of Tooth Profile for a Pair of Spur Gears to Make its Rotational Vibration Equal Zero

1992 ◽  
Author(s):  
Yurong Cai ◽  
Teru Hayashi
Keyword(s):  
Static Load ◽  
Tooth Profile ◽  
Parameter Study ◽  
Exact Equation ◽  
Spur Gears ◽  
Contact Ratio ◽  
Profile Error ◽  
Vibration Model ◽  
Modification Method ◽  
Rotational Vibration

Abstract This paper develops an optimum modification method of tooth profile for a pair of spur gears to make its rotational vibration become zero by using an exact vibration model. By minimizing the equivalent exciting force, which includes the effects of the static load, time-varying stiffness, and relative tooth profile error, each optimum modification curve for each gear pair with different designed contact ratios can be obtained. The magnitude and the shape of the optimum modification curve depend upon the value of the designed contact ratio ε strongly. Especially, the concave modification curve is obtained in case of ε ≤ 1.1. The effect of the optimum modification on eliminating the vibration, is verified by the numerical calculation using an exact equation of vibration. A parameter study is presented to investigate the effect of running condition.

Parametric vibration of split gears induced by time-varying mesh stiffness

2014 ◽  
Vol 229 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Dongsheng Zhang ◽  
Shiyu Wang
Keyword(s):  
Parametric Vibration ◽  
Design Parameters ◽  
Time Varying ◽  
Contact Ratio ◽  
Mesh Stiffness ◽  
Rotational Model ◽  
Helical Gears ◽  
Multi Scale ◽  
Rotational Vibration ◽  
The Relationship

Time-varying mesh stiffness is a significant excitation source within gear systems. Split gear (or laminated gear, phase gear) is an interesting design using equally phased gear-slices, which can remarkably reduce the mesh stiffness fluctuation like helical gears but completely avoid the axial force. This work examines a split gear pair to address the suppression of the mesh stiffness fluctuation and rotational vibration thereof, especially the relationship between the key design parameters including the number of slice, contact ratio, and damping, and the parametric vibration. For these aims, this work develops a purely rotational model, based on which the multi-scale method is employed to determine stability boundaries. The results imply that the unstable zones are related to the mesh phase determined by the number of slices and contact ratio, and these zones can be diminished by the damping. The analytical predictions are numerically verified by Floquet theory.

scholarly journals Bianchi type–I Model with Time Varying Λ and G: The Generalized Solution

2020 ◽  
Vol 29 (1) ◽  
pp. 89-93
Author(s):  
Alnadhief H. A. Alfedeel
Keyword(s):  
Analytical Solution ◽  
Bianchi Type ◽  
Generalized Solution ◽  
Type I ◽  
Time Varying ◽  
Field Equations ◽  
Geometric Function ◽  
Varying Λ ◽  
The Universe ◽  
Average Scale Factor

AbstractIn this paper, we have investigated the homogeneous and anisotropic Bianchi type–I cosmological model with a time-varying Newtonian and cosmological constant. We have analytically solved Einstein’s field equations (EFEs) in the presence of a stiff-perfect fluid. We show that the analytical solution for the average scale factor for the generalized Friedman equation involves the hyper-geometric function. We have studied the physical and kinematical quantities of the model, and it is found that the universe becomes isotropic at late times.

scholarly journals Intermittent heat instabilities in an air plume

2016 ◽  
Vol 23 (4) ◽  
pp. 319-330
Author(s):  
Jean-Louis Le Mouël ◽  
Vladimir G. Kossobokov ◽  
Frederic Perrier ◽  
Pierre Morat
Keyword(s):  
Temperature Sensors ◽  
Time Varying ◽  
First Order ◽  
Spatial Function ◽  
Universal Feature ◽  
Classical Models ◽  
Set Up ◽  
Plume Flow ◽  
Temperature Time ◽  
Classical Shape

Abstract. We report the results of heating experiments carried out in an abandoned limestone quarry close to Paris, in an isolated room of a volume of about 400 m3. A heat source made of a metallic resistor of power 100 W was installed on the floor of the room, at distance from the walls. High-quality temperature sensors, with a response time of 20 s, were fixed on a 2 m long bar. In a series of 24 h heating experiments the bar had been set up horizontally at different heights or vertically along the axis of the plume to record changes in temperature distribution with a sampling time varying from 20 to 120 s. When taken in averages over 24 h, the temperatures present the classical shape of steady-state plumes, as described by classical models. On the contrary, the temperature time series show a rich dynamic plume flow with intermittent trains of oscillations, spatially coherent, of large amplitude and a period around 400 s, separated by intervals of relative quiescence whose duration can reach several hours. To our knowledge, no specific theory is available to explain this behavior, which appears to be a chaotic interaction between a turbulent plume and a stratified environment. The observed behavior, with first-order factorization of a smooth spatial function with a global temporal intermittent function, could be a universal feature of some turbulent plumes in geophysical environments.

Vibration Analysis of the Continuous Truss Girder Bridge by the Finite Truss Elements

2011 ◽  
Vol 268-270 ◽  
pp. 557-560
Author(s):  
Shi Ruo Yang
Keyword(s):  
Composite System ◽  
Elastic System ◽  
Total Potential Energy ◽  
Time Varying ◽  
Girder Bridges ◽  
Total Potential ◽  
Vibration Responses ◽  
Pass Through ◽  
Girder Bridge ◽  
Set Up

The train and the continuous truss girder bridge are coupled together as one composite system. Truss girder bridge is idealized as an assemblage of finite truss element. The equations of the train and truss girder bridges time varying system are set up by using the principle of total potential energy with stationary value in elastic system dynamics and the“set-in-right-position”rule for forming structural matrices. This method is more convenient than the finite elements. The vibration responses of the train and bridge are calculated when the the passenger trains pass through a continuous truss girder bridge at speeds of 90km/h and 120km/h The results show that the passenger train can pass it safely and comfortably

Analytical Model of the Efficiency of Spur Gears: Study of the Influence of the Design Parameters

2011 ◽  
Author(s):  
Miguel Pleguezuelos ◽  
Jose´ I. Pedrero ◽  
Miryam B. Sa´nchez
Keyword(s):  
Load Distribution ◽  
Gear Ratio ◽  
Design Parameters ◽  
Spur Gears ◽  
Transmitted Power ◽  
Power Losses ◽  
Contact Ratio ◽  
Complete Study ◽  
Uniform Model ◽  
Analytical Expressions

An analytic model to compute the efficiency of spur gears has been developed. It is based on the application of a non-uniform model of load distribution obtained from the minimum elastic potential criterion and a simplified non-uniform model of the friction coefficient along the path of contact. Both conventional and high transverse contact ratio spur gears have been considered. Analytical expressions for the power losses due to friction, for the transmitted power and for the efficiency are presented. From this model, a complete study of the influence of some design parameters (as the number of teeth, the gear ratio, the pressure angle, the addendum modification coefficient, etc.) on the efficiency is presented.

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