Uncertainty Considerations in the Dynamics of Gear-Pair

2012 ◽  
Author(s):  
Fisseha M. Alemayehu ◽  
Stephen Ekwaro-Osire
Keyword(s):  
Parameter Uncertainty ◽  
Traditional Approach ◽  
Design Parameters ◽  
Dynamic Factor ◽  
Gear Pair ◽  
The Novel ◽  
Gear Design ◽  
Pair Model ◽  
Multibody Dynamic ◽  
Gear Systems

Gears and Gear systems are subjected to uncertainty of design parameters and loading caused by inherent conditions, measurement and manufacturing errors. Hence, the motivation of this work is to improve the deterministic design practice of gears and gear systems. A probabilistic rigid multibody dynamic gear-pair model with design and load uncertainties has been developed and analyzed. Rigid gear-pair model was developed in multibody dynamics software ADAMS and parameter uncertainty and probabilistic analysis was performed from separate probabilistic software called NESSUS. To perform the probabilistic multibody analysis, ADAMS and NESSUS were interfaced using MATLAB. The effect of parameter uncertainty on dynamic factor, DF of a gear pair was investigated. The sensitivity of DF to five uncertain loading and design parameters were also determined. This paper has demonstrated the importance of the novel PMBD modeling approach to gear design and dynamic factor analysis. The method has brought a new dimension of design approach of gears and gear systems than traditional approach that considers a certain empirically defined dynamic rating factors. In addition to revealing system reliability or under-performance through probability of failure, it also helps designers to consider certain variables critically through the sensitivity results.

Uncertainty Considerations in the Dynamic Loading and Failure of Spur Gear Pairs1

2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Fisseha M. Alemayehu ◽  
Stephen Ekwaro-Osire
Keyword(s):  
Spur Gear ◽  
Design Parameters ◽  
Dynamic Factor ◽  
Performance Measurements ◽  
Random Loading ◽  
Pair Model ◽  
Multibody Dynamic ◽  
Gear Systems ◽  
Rigid Multibody ◽  
Analysis Of Performance

Gears and gear systems, like any other mechanical system, are subjected to design parameter, and loading uncertainties emanating from inherent randomness, manufacturing, and assembly errors. The traditional deterministic approach to the design of such systems overlooks these uncertainties. This work presents a novel probabilistic multibody dynamic analysis (PMBDA) that enhances the deterministic design practice of gears and gear systems. A contact based, rigid multibody spur gear pair model with random loading, and design parameters has been developed. An advanced mean based on fast probability integration method was implemented to perform a reliability analysis of performance measurements: dynamic factor, root bending stress, and fatigue life of gears. Probabilistic sensitivity analysis of these performance functions to several random variables was also determined. In addition to revealing system reliability or probability of failure, the PMBDA approach also helps designers to consider certain variables critically.

Oil Churning Power Losses of a Gear Pair: Experiments and Model Validation

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
S. Seetharaman ◽  
A. Kahraman ◽  
M. D. Moorhead ◽  
T. T. Petry-Johnson
Keyword(s):  
Power Loss ◽  
Spur Gear ◽  
Companion Paper ◽  
Design Parameters ◽  
Measured Parameter ◽  
Gear Pair ◽  
Power Losses ◽  
Gear Design ◽  
Face Width ◽  
Wide Range

This paper presents the results of an experimental study on load-independent (spin) power losses of spur gear pairs operating under dip-lubricated conditions. The experiments were performed over a wide range of operating speed, temperature, oil levels, and key gear design parameters to quantify their influence on spin power losses. The measurements indicate that the static oil level, rotational speed, and face width of gears have a significant impact on spin power losses compared with other parameters such as oil temperature, gear module, and the direction of gear rotation. A physics-based gear pair spin power loss formulation that was proposed in a companion paper (Seetharaman and Kahraman, 2009, “Load-Independent Spin Power Losses of a Spur Gear Pair: Model Formulation,” ASME J. Tribol., 131, p. 022201) was used to simulate these experiments. Direct comparisons between the model predictions and measurements are provided at the end to demonstrate that the model is capable of predicting the measured spin power loss values as well as the measured parameter sensitivities reasonably well.

scholarly journals Principal stress lines based design method of lightweight and low vibration amplitude gear web

2021 ◽  
Vol 18 (6) ◽  
pp. 7060-7075
Author(s):  
Ganjun Xu ◽  
◽  
Ning Dai ◽  
Sukun Tian ◽  
Keyword(s):  
Principal Stress ◽  
Vibration Amplitude ◽  
Design Method ◽  
Web Design ◽  
Design Parameters ◽  
The Novel ◽  
Experimental Platform ◽  
Gear Design ◽  
Optimal Distance ◽  
The Relationship

<abstract> <p>A lightweight and low vibration amplitude web design method was investigated to reduce gear weight and noise. It was based upon the relationship between length and orthogonality that the principal stress lines were designed at the gear web. By constructing a vibration control model with gear design parameters, the optimal distance was calculated. By offsetting the principal stress lines at the optimal distance, the lightweight gear web with the low vibration amplitude was then generated. A vibration experimental platform was built to verify the novel gear vibration performances, and it was compared with other gears with the same web's porosity to verify loading performance. The experimental results indicated that compared with the solid gear, the novel gear is 20.50% lighter and with a 29.46% vibration amplitude reduction.</p> </abstract>

Effect of design parameters on stresses occurring at the tooth root in a spur gear pressed on a shaft

2021 ◽  
pp. 095440892199529
Author(s):  
Fatih Güven
Keyword(s):  
Internal Pressure ◽  
Tangential Stress ◽  
Spur Gear ◽  
Design Parameters ◽  
Interference Fit ◽  
Gear Design ◽  
Compact Design ◽  
Fit Tolerance ◽  
Moderate Stress ◽  
Good Agreement

Gears are commonly used in transmission systems to adjust velocity and torque. An integral gear or an interference fit could be used in a gearbox. Integral gears are mostly preferred as driving gear for a compact design to reduce the weight of the system. Interference fit makes the replacement of damaged gear possible and re-use of the shaft compared to the integral shaft. However, internal pressure occurs between mating surfaces of the components mated. This internal pressure affects the stress distribution at the root and bottom land of the gear. In this case, gear parameters should be re-considered to assure gear life while reducing the size of the gear. In this study, interference fitted gear-shaft assembly was examined numerically. The effects of rim thickness, profile shifting, module and fit tolerance on bending stress occurring at the root of the gear were investigated to optimize gear design parameters. Finite element models were in good agreement with analytical solutions. Results showed that the rim thickness of the gear is the main parameter in terms of tangential stress occurring at the bottom land of the gear. Positive profile shifting reduces the tangential stress while the pitch diameter of the gear remains constant. Also, lower tolerance class could be selected to moderate stress for small rim thickness.

Face Gear Width Prediction Using the DOE Method

2008 ◽  
Vol 130 (10) ◽  
Author(s):  
Michèle Guingand ◽  
Didier Remond ◽  
Jean-Pierre de Vaujany
Keyword(s):  
Regression Model ◽  
Simple Formula ◽  
Design Parameters ◽  
Face Gear ◽  
Main Design ◽  
Gear Design ◽  
Simple Regression Model ◽  
Numerical Tool ◽  
Influential Parameters ◽  
Simple Regression

This paper deals with face gear design. The goal is to propose a simple formula for predicting the width of the wheel as a function of the main design parameters. A specific software was used to achieve this goal. This numerical tool is able to simulate the geometry and the quasistatic loaded behavior of a face gear. The statistical method used for analyzing the influence of data is described: The design of experiments leads to a simple regression model taking into account the influential parameters and their couplings. In the last part of this paper, the results of the formulas are compared to those of the software and an optimal design is proposed based on the regression model.

Direct Sensitivity Analysis of Spatial Multibody Systems With Joint Friction Using Index-1 Formulation

2021 ◽  
Author(s):  
Adwait Verulkar ◽  
Corina Sandu ◽  
Daniel Dopico ◽  
Adrian Sandu
Keyword(s):  
Sensitivity Analysis ◽  
Dynamic Systems ◽  
Multibody Systems ◽  
Friction Model ◽  
Design Parameters ◽  
Adjoint Sensitivity ◽  
Joint Friction ◽  
Multibody Dynamic ◽  
Model Dynamics ◽  
Direct Sensitivity

Abstract Sensitivity analysis is one of the most prominent gradient based optimization techniques for mechanical systems. Model sensitivities are the derivatives of the generalized coordinates defining the motion of the system in time with respect to the system design parameters. These sensitivities can be calculated using finite differences, but the accuracy and computational inefficiency of this method limits its use. Hence, the methodologies of direct and adjoint sensitivity analysis have gained prominence. Recent research has presented computationally efficient methodologies for both direct and adjoint sensitivity analysis of complex multibody dynamic systems. The contribution of this article is in the development of the mathematical framework for conducting the direct sensitivity analysis of multibody dynamic systems with joint friction using the index-1 formulation. For modeling friction in multibody systems, the Brown and McPhee friction model has been used. This model incorporates the effects of both static and dynamic friction on the model dynamics. A case study has been conducted on a spatial slider-crank mechanism to illustrate the application of this methodology to real-world systems. Using computer models, with and without joint friction, effect of friction on the dynamics and model sensitivities has been demonstrated. The sensitivities of slider velocity have been computed with respect to the design parameters of crank length, rod length, and the parameters defining the friction model. Due to the highly non-linear nature of friction, the model dynamics are more sensitive during the transition phases, where the friction coefficient changes from static to dynamic and vice versa.

Study on the compound transmission mechanism of the curve-face gear based on screw theory

2017 ◽  
Vol 232 (17) ◽  
pp. 3115-3124 ◽  
Author(s):  
Chao Lin ◽  
Yanqun Wei ◽  
Zhiqin Cai
Keyword(s):  
Screw Theory ◽  
Transmission Mechanism ◽  
Tooth Surface ◽  
Design Parameters ◽  
Gear Pair ◽  
Face Gear ◽  
Cylindrical Gear ◽  
Cam Mechanism ◽  
Conjugate Surfaces ◽  
Curve Face

The compound transmission mechanism of curve-face gear is a new type of gear transmission based on the cam mechanism and the curve-face gear pair. It combines the transmission characteristics of the cam mechanism and noncircular bevel gear. When the compound transmission mechanism of curve-face gear is engaged in the meshing transmission, the rotating center of the cylindrical gear is fixed and used as the driving wheel, and the curve-face gear can generate the helical motion around the axis. In this paper, the meshing characteristics and motion laws of the compound transmission mechanism of the curve-face gear are studied based on the theory of screw. Based on the meshing theory of gears, the coordinate system of conjugate surfaces is established, the basic meshing theory and equation are obtained. On this basis, combined with the principle of the cam, the transmission principle is analyzed by the screw theory. The tooth surface equation of the compound transmission mechanism of curve-face gear is deduced based on the meshing theory and the related knowledge of geometry. The motion law of the curve-face gear and the change of the motion law with the change of the basic parameters of the gear pair with different design parameters are calculated and analyzed. An experimental platform is built to verify the law of motion, and the experimental results are compared with the theoretical values. The correctness of the theoretical analysis is verified, which provides a new way for the research of the compound transmission mechanism of the curve-face gear.

scholarly journals Type 2 diabetes therapeutic strategies: why don't we see the «ELEPHANT» in the room?

2016 ◽  
Vol 19 (4) ◽  
pp. 341-349 ◽  
Author(s):  
Shmuel Levit ◽  
Shmuel Giveon ◽  
Yury I. Philippov ◽  
Ivan Panchev Domuschiev ◽  
Amir Zivony
Keyword(s):  
Type 2 Diabetes ◽  
Traditional Approach ◽  
Treatment Method ◽  
Past Century ◽  
The Novel ◽  
Energy Effect ◽  
Practical Utilization ◽  
Recommended Treatment ◽  
Reversible Condition

During the past two decades, the unequivocally recommended treatment method of Type 2 diabetes mellitus was insulin administration and intensification in the earliest possible stage of the diagnosis. This approach is not only unfounded but was never scientifically proven. Yet, it has been zealously advocated to medical professionals. In fact, a sound body of evidence disproves this long-standing treatment approach. This method is a cornerstone of, what we now know to be two great illusions of past century, namely, glucocentrism and intensification. Numerous recently published studies provide alarming data regarding serious side effects of blind intensification and insulin overdosing in T2DM. They raise major concerns and call for revision of the traditional approach. Since insulin is an integral and deeply rooted part of the intensification agenda of treating T2DM, it has now suffered a serious drawback. Alternatively, in this review authors present the novel Gravicentric (Energy) concept of T2DM acceptance and therapy. They offer a new classification of anti-diabetes drugs based on their energy effect and present their Gravicentric Algorithm for wide practical utilization. For that reason, the "ELEPHANT" abbreviation was found as a helpful reminder. Viewing T2DM as disease of energy balance together with anti – energy drugs implementation provide medical doctors an unique opportunity to transform T2DM from "slowly – progressive" disease to rapidly reversible condition, which it actually is.

The Mechanism and Solution of Harmonic Gear Whine Noise in Automotive Transmission Systems

2007 ◽  
Author(s):  
Jaegon Yoo ◽  
Koo-Tae Kang ◽  
Jin-Wook Huh ◽  
Chimahn Choi
Keyword(s):  
Surface Structure ◽  
Design Parameters ◽  
Test Results ◽  
Gear Noise ◽  
Transfer Path ◽  
Gear Design ◽  
Automotive Transmission ◽  
Wave Patterns ◽  
Tooth Modification ◽  
Harmonic Noise

Since gear noise in automotive is one of the most unpleasant noises for passengers, various solutions, such as gear design optimization, tooth modification and transfer path reformations in the vehicle have been developed. But, these attempts are mainly focused on the fundamental mesh excitation of the gear set without any consideration of their harmonic noise (1st, 2nd or higher). Harmonic gear whine noise is easily audible in the vehicle because of their high frequency characteristics in spite of low sound pressure level. This annoying pure-tone noise is usually issued in the transmission system composed of the gears produced by grinding process. This paper will present the main sources of this harmonic gear whine noise with the test results of gears with identical design parameters but having different surface structure (roughness parameters, wave patterns). Additionally, manufacturing guidelines of gear surface structure will be proposed at the end of this paper.

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