Spur Gear Lubrication Analysis with Dynamic Loads

Liu, Huaiju; Mao, Ken; Zhu, Caichao; Chen, Siyu; Xu, Xiangyang; Liu, Mingyong

doi:10.1080/10402004.2012.725805

Cited by 38 publications

(26 citation statements)

References 32 publications

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“…Following the developments of the EHL and micro-EHL theories, gear lubrication has been extensively studied in recent years and relevant numerical models have been developed [29,30]. For clarity, essential equations are explained here.…”

Section: Lubrication Modelmentioning

confidence: 99%

Study on contact fatigue of a wind turbine gear pair considering surface roughness

Liu

Zhu

et al. 2019

Friction

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Contact fatigue issues become more and more crucial in gear industry as they significantly affect the reliability and service life of associated mechanical systems such as wind turbine gearboxes. The contact fatigue behavior is mostly determined by the mechanical properties of materials and stress fields near the contact area, which is further influenced by the lubrication and surface roughness due to pressure fluctuations. In this study, a numerical model incorporating the lubrication state, tooth surface roughness, residual stress, and mechanical properties of the material is developed to determine the contact fatigue behavior of a megawatt level wind turbine carburized gear. The variations of the hardness and residual stress along the depth were characterized by the Vickers hardness measurement and X-ray diffraction test, respectively. The elastohydrodynamic lubrication theory was applied to predict the contact pressure distribution, highlighting the influence of the surface roughness that stemed from the original measurement through an optical profiler. The stress histories of the studied material points during a complete contact loading cycle were fast calculated using the discreteconcrete fast Fourier transformation (DC-FFT) method. Modified Dang Van diagrams under different working conditions were determined to estimate the contact fatigue failure risk. The effect of the root mean square (RMS) value of the surface roughness on the failure risk at critical material points were discussed in detail. Results revealed that the surface roughness significantly increases the contact fatigue failure risk within a shallow area, and the maximum risk appears near the surface.

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Section: Lubrication Modelmentioning

confidence: 99%

Study on contact fatigue of a wind turbine gear pair considering surface roughness

Liu

Zhu

et al. 2019

Friction

Self Cite

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“…In fact, many rheology models have been introduced to discover the characteristic of non-Newtonian lubricant as shown by Johnson and Tevaarwerk [5] such as the Ree-Eyring model, the power-law model, the Johnson-Tevaarwerk model and others. The Ree-Eyring model is recommended by many researchers and is applied extensively [6,7] for lubrication performance studies of, for example, gears and cams.…”

Section: Introductionmentioning

confidence: 99%

Non-Newtonian Film Thickness Formation in Ultra-thin Film

Al-Samieh

2019

IJAME

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This paper aims to show the characteristics of ultra-thin films for non-Newtonian fluid using Ree-Eyring model where intermolecular forces of solvation and Van der Waal's are considered in addition to the hydrodynamic action to fulfill an identified need for such a conjunction. In this case, the film thickness and pressure distribution are obtained by simultaneous solution of the modified Reynolds’ equation incorporating the effect of non-Newtonian fluid, film thickness equation including elastic deformation caused by all contributing pressures and the load balance equation using Newton-Raphson method with Gauss-Seidel iterations. Effect of changing the operating conditions of speed, load, Eyring shear stress and slide-roll ratio on the characteristic of the contact has been studied. The results show that, for the case where the hydrodynamic action is the only pressure acting to support the applied load capacity, the film thickness and the pressure gradient at the exit of the contact obtained using non-Newtonian model is different than that formed using the Newtonian model especially for the increased value of slide-roll ratio. The main results of this study are that for ultra-thin film, the film thickness formed using non-Newtonian model is smaller compared to that obtained using Newtonian case and the discretization of the film thickness as the gap is reduced occurs similar to the results obtained using Newtonian model. The pressure shape shows no difference compared to that formed using the Newtonian case in which an oscillation around the Hertizan contact pressure shape due to the solvation effect appears. The results also show that for ultra-thin film, changing the Eyring shear stress does not affect the film thickness formation.

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“…The starved EHL model is based upon the fully flooded EHL model the authors developed [19]. The Ree-Eyring fluid is assumed to represent the non-Newtonian behavior.…”

Section: Methodsmentioning

confidence: 99%