The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Rajendra Singh - One of the best experts on this subject based on the ideXlab platform.
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prediction of dynamic Friction forces in spur gears using alternate Sliding Friction formulations
Journal of Sound and Vibration, 2008Co-Authors: Song He, Rajendra SinghAbstract:In this communication, several Sliding Friction formulations used in spur gear dynamics are examined and compared in terms of the predictions of interfacial Friction forces and off-line-of-action motions. Competing Friction formulations include Coulomb models with time-varying Friction coefficients and empirical expressions based on elasto-hydrodynamic and/or boundary lubrication regime principles. Predicted results compare well with Friction force measurements.
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effect of Sliding Friction on the dynamics of spur gear pair with realistic time varying stiffness
Journal of Sound and Vibration, 2007Co-Authors: Song He, Rajendra Gunda, Rajendra SinghAbstract:Abstract The chief objective of this article is to propose a new method of incorporating the Sliding Friction and realistic time-varying stiffness into an analytical (multi-degree-of-freedom) spur gear model and to evaluate their effects. An accurate finite element/contact mechanics analysis code is employed, in the “static” mode, to compute the mesh stiffness at every time instant under a range of loading conditions. Here, the time-varying stiffness is calculated as an effective function which may also include the effect of profile modifications. The realistic mesh stiffness is then incorporated into the linear time-varying spur gear model with the contributions of Sliding Friction. Proposed methods are illustrated via two spur gear examples and validated by using the finite element in the “dynamic” mode as experimental results. A key question whether the Sliding Friction is indeed the source of the off-line-of-action forces and motions is then answered by our analytical model. Finally, the effect of the profile modification on the dynamic transmission error has been analytically examined under the influence of Sliding Friction. For instance, the linear tip relief introduces an amplification in the off-line-of-action forces and motions due to an out of phase relationship between the normal load and Friction forces.
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Dynamic Interactions Between Sliding Friction and Tip Relief in Spur Gears
Volume 7: 10th International Power Transmission and Gearing Conference, 2007Co-Authors: Song He, Rajendra SinghAbstract:The chief objective of this article is to examine dynamic interactions between Sliding Friction and profile modifications in a spur gear pair. First, a new computational method is proposed that incorporates the Sliding Friction and realistic time-varying stiffness into a multi-degree-of-freedom system model. Second, competing Friction formulations, such as the Coulomb dry Friction model and empirical expressions based on elasto-hydrodynamic and/or boundary lubrication regime principles, are briefly evaluated and validated by comparing Friction force predictions with measurements. Third, effect of the profile modification on the dynamic transmission error is analytically examined under the influence of Sliding Friction. An out-of-phase relationship between the normal load and Friction force is found to be critical as it could amplify motions or forces in the off-line-of-action direction. Typical tip relief schemes are examined including the perfect involute profile (baseline), short tip relief (at light load), intermediate tip relief (at medium load) and long tip relief (at peak load). Case studies are evaluated over a range of operating loads; interactions between Sliding Friction and profile modifications are observed. Finally, principles that could minimize dynamic transmission errors in the presence of Sliding Friction are introduced.Copyright © 2007 by ASME
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Analytical Study of Helical Gear Dynamics With Sliding Friction Using Floquet Theory
Volume 7: 10th International Power Transmission and Gearing Conference, 2007Co-Authors: Song He, Rajendra SinghAbstract:Analytical models of a helical gear pair are developed in order to examine the effect of Sliding Friction on the dynamic transmission error. Simplified 6 degree-of-freedom and single degree-of-freedom analytical models are developed. These models characterize the contact plane dynamics and capture the velocity reversal at the pitch line due to Sliding Friction. By assuming a constant mesh stiffness density along the contact lines, a linear time-varying model (with parametric excitation) is obtained. The effect of Sliding Friction is quantified by an effective mesh stiffness term. Floquet theory is then used to obtain closed-form solutions to the dynamic transmission error given periodic piece-wise linear tooth stiffness function. Responses to both initial conditions and forcing function under a nominal torque are derived. Analytical models are validated by comparing predictions with numerical simulations. Finally, parametrically-induced instability issues are briefly mentioned.Copyright © 2007 by ASME
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inclusion of Sliding Friction in contact dynamics model for helical gears
Journal of Mechanical Design, 2007Co-Authors: Song He, Rajendra Gunda, Rajendra SinghAbstract:This paper proposes a new analytical model for helical gears that characterizes the contact plane dynamics and captures the velocity reversal at the pitch line due to Sliding Friction. First, the tooth stiffness density function along the contact lines is calculated by using a finite element code. Analytical formulations are then derived for the multidimensional mesh forces and moments. Contact zones for multiple tooth pairs in contact are identified, and the associated integration algorithms are derived. A new 12-degree-of-freedom, linear time-varying model with Sliding Friction is then developed. It includes rotational and translational motions along the line-of-action, off-line-of-action, and axial directions. The methodology is also illustrated by predicting time and frequency domain results for several values of the coefficient of Friction.
Song He - One of the best experts on this subject based on the ideXlab platform.
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prediction of dynamic Friction forces in spur gears using alternate Sliding Friction formulations
Journal of Sound and Vibration, 2008Co-Authors: Song He, Rajendra SinghAbstract:In this communication, several Sliding Friction formulations used in spur gear dynamics are examined and compared in terms of the predictions of interfacial Friction forces and off-line-of-action motions. Competing Friction formulations include Coulomb models with time-varying Friction coefficients and empirical expressions based on elasto-hydrodynamic and/or boundary lubrication regime principles. Predicted results compare well with Friction force measurements.
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effect of Sliding Friction on the dynamics of spur gear pair with realistic time varying stiffness
Journal of Sound and Vibration, 2007Co-Authors: Song He, Rajendra Gunda, Rajendra SinghAbstract:Abstract The chief objective of this article is to propose a new method of incorporating the Sliding Friction and realistic time-varying stiffness into an analytical (multi-degree-of-freedom) spur gear model and to evaluate their effects. An accurate finite element/contact mechanics analysis code is employed, in the “static” mode, to compute the mesh stiffness at every time instant under a range of loading conditions. Here, the time-varying stiffness is calculated as an effective function which may also include the effect of profile modifications. The realistic mesh stiffness is then incorporated into the linear time-varying spur gear model with the contributions of Sliding Friction. Proposed methods are illustrated via two spur gear examples and validated by using the finite element in the “dynamic” mode as experimental results. A key question whether the Sliding Friction is indeed the source of the off-line-of-action forces and motions is then answered by our analytical model. Finally, the effect of the profile modification on the dynamic transmission error has been analytically examined under the influence of Sliding Friction. For instance, the linear tip relief introduces an amplification in the off-line-of-action forces and motions due to an out of phase relationship between the normal load and Friction forces.
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Dynamic Interactions Between Sliding Friction and Tip Relief in Spur Gears
Volume 7: 10th International Power Transmission and Gearing Conference, 2007Co-Authors: Song He, Rajendra SinghAbstract:The chief objective of this article is to examine dynamic interactions between Sliding Friction and profile modifications in a spur gear pair. First, a new computational method is proposed that incorporates the Sliding Friction and realistic time-varying stiffness into a multi-degree-of-freedom system model. Second, competing Friction formulations, such as the Coulomb dry Friction model and empirical expressions based on elasto-hydrodynamic and/or boundary lubrication regime principles, are briefly evaluated and validated by comparing Friction force predictions with measurements. Third, effect of the profile modification on the dynamic transmission error is analytically examined under the influence of Sliding Friction. An out-of-phase relationship between the normal load and Friction force is found to be critical as it could amplify motions or forces in the off-line-of-action direction. Typical tip relief schemes are examined including the perfect involute profile (baseline), short tip relief (at light load), intermediate tip relief (at medium load) and long tip relief (at peak load). Case studies are evaluated over a range of operating loads; interactions between Sliding Friction and profile modifications are observed. Finally, principles that could minimize dynamic transmission errors in the presence of Sliding Friction are introduced.Copyright © 2007 by ASME
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Analytical Study of Helical Gear Dynamics With Sliding Friction Using Floquet Theory
Volume 7: 10th International Power Transmission and Gearing Conference, 2007Co-Authors: Song He, Rajendra SinghAbstract:Analytical models of a helical gear pair are developed in order to examine the effect of Sliding Friction on the dynamic transmission error. Simplified 6 degree-of-freedom and single degree-of-freedom analytical models are developed. These models characterize the contact plane dynamics and capture the velocity reversal at the pitch line due to Sliding Friction. By assuming a constant mesh stiffness density along the contact lines, a linear time-varying model (with parametric excitation) is obtained. The effect of Sliding Friction is quantified by an effective mesh stiffness term. Floquet theory is then used to obtain closed-form solutions to the dynamic transmission error given periodic piece-wise linear tooth stiffness function. Responses to both initial conditions and forcing function under a nominal torque are derived. Analytical models are validated by comparing predictions with numerical simulations. Finally, parametrically-induced instability issues are briefly mentioned.Copyright © 2007 by ASME
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inclusion of Sliding Friction in contact dynamics model for helical gears
Journal of Mechanical Design, 2007Co-Authors: Song He, Rajendra Gunda, Rajendra SinghAbstract:This paper proposes a new analytical model for helical gears that characterizes the contact plane dynamics and captures the velocity reversal at the pitch line due to Sliding Friction. First, the tooth stiffness density function along the contact lines is calculated by using a finite element code. Analytical formulations are then derived for the multidimensional mesh forces and moments. Contact zones for multiple tooth pairs in contact are identified, and the associated integration algorithms are derived. A new 12-degree-of-freedom, linear time-varying model with Sliding Friction is then developed. It includes rotational and translational motions along the line-of-action, off-line-of-action, and axial directions. The methodology is also illustrated by predicting time and frequency domain results for several values of the coefficient of Friction.
Xuefeng Chen - One of the best experts on this subject based on the ideXlab platform.
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Influence of Sliding Friction on the Dynamic Characteristics of a Planetary Gear Set With the Improved Time-Varying Mesh Stiffness
Journal of Mechanical Design, 2020Co-Authors: Baijie Qiao, Zhixian Shen, Zhibo Yang, Xuefeng ChenAbstract:Abstract Acting as an important internal excitation, Sliding Friction can cause the vibration and noise of the planetary gear set. In this paper, a dynamic model is developed to study the influence of Sliding Friction on the dynamic characteristics of the planetary gear set by including the time-varying mesh stiffness (TVMS), Sliding Friction forces and torques. An improved analytical model is proposed to calculate the TVMS with Sliding Friction. The explicit analytical expressions of the Sliding Friction forces and torques are also derived. Three kinds of different models are applied to investigate the influence of Sliding Friction: (1) the basic model: Sliding Friction is neglected in the dynamic model; (2) the improved model I: only the Sliding Friction forces and torques are considered in the dynamic model; and (3) the improved model II: both the influence of Sliding Friction on the TVMS and the Sliding Friction forces and torques are introduced into the dynamic model. The planetary gear set with three equally spaced planet gears is applied to analyze the dynamic characteristics under Sliding Friction. The simulation results show that the dynamic characteristics can be enhanced or disturbed by Sliding Friction. In the end, the dynamic model is validated by the experiments. Therefore, the influence of Sliding Friction is non-negligible when investigating the dynamic characteristics of the planetary gear set. The developed dynamic model provides a feasible dynamic research scheme for the planetary gear set with Sliding Friction.
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Time-varying mesh stiffness calculation of a planetary gear set with the spalling defect under Sliding Friction
Meccanica, 2020Co-Authors: Baijie Qiao, Zhixian Shen, Zhibo Yang, Xuefeng ChenAbstract:Time-varying mesh stiffness (TVMS) is an important excitation source of a planetary gear set. Sliding Friction and spalling defects have significant effect on the TVMS. Accurate evaluation of the TVMS can help obtain the vibration characteristics and further detect the spalling defects of the planetary gear set. In this paper, an improved analytical model is proposed to calculate the TVMS of the planetary gear set with Sliding Friction by considering the tooth profile beginning with the root circle. Then the impact of spalling defects on the TVMS is investigated. The results show that the improved analytical model can increase the precision of the TVMS. Besides, the effect of Sliding Friction and spalling defects on the TVMS is significant. This study offers a basis for dynamic performance analysis of a planetary gear set with spalling defects under Sliding Friction.
D A Hills - One of the best experts on this subject based on the ideXlab platform.
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an elastic plastic asperity interaction model for Sliding Friction
Tribology International, 2011Co-Authors: Daniel M Mulvihill, Mehmet E Kartal, D Nowell, D A HillsAbstract:A finite-element model of the interaction of an elastic–plastic asperity junction based on cylindrical or spherical asperities is used to predict Sliding Friction coefficients. The modelling differs from previous work by permitting greater asperity overlaps, enforcing an interface adhesional shear strength, and allowing material failure. The results of the modelling were also used to predict Friction coefficients for a stochastic rough surface. The asperities were based on the titanium alloy Ti-6Al-4V, and the magnitudes of the predicted Friction coefficients were generally representative of experimental measurements of Sliding Friction. The results suggest that Friction arises from both plasticity and tangential interface adhesion.
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An elastic–plastic asperity interaction model for Sliding Friction
Tribology International, 2011Co-Authors: Daniel M Mulvihill, Mehmet E Kartal, D Nowell, D A HillsAbstract:A finite-element model of the interaction of an elastic–plastic asperity junction based on cylindrical or spherical asperities is used to predict Sliding Friction coefficients. The modelling differs from previous work by permitting greater asperity overlaps, enforcing an interface adhesional shear strength, and allowing material failure. The results of the modelling were also used to predict Friction coefficients for a stochastic rough surface. The asperities were based on the titanium alloy Ti-6Al-4V, and the magnitudes of the predicted Friction coefficients were generally representative of experimental measurements of Sliding Friction. The results suggest that Friction arises from both plasticity and tangential interface adhesion.
I M Hutchings - One of the best experts on this subject based on the ideXlab platform.
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reduction of the Sliding Friction of metals by the application of longitudinal or transverse ultrasonic vibration
Tribology International, 2004Co-Authors: V C Kumar, I M HutchingsAbstract:Abstract The influence on Sliding Friction of ultrasonic vibration both parallel and perpendicular to the Sliding direction has been studied for samples of aluminium alloy, copper, brass and stainless steel Sliding against tool steel. Experiments were performed at a mean Sliding speed of 50 mm s −1 , and at mean contact pressures up to 0.7 MPa, with vibration amplitudes up to 10 μm at 20 kHz. Significant reduction in Sliding Friction was observed (up to >80%) and good agreement was found between the measured values and the predictions of two simple models for the effects of longitudinal and transverse vibrations. Longitudinal vibration produces greater reduction in Friction than transverse vibration at the same amplitude and frequency. At high vibration amplitudes, the reduction in Friction was less than that predicted by the models, because significant metallic transfer occurred from the softer metals to the tool steel counter surface.
