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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/2240

Title: Finite Element Based Surface Fatigue Estimation in Involute Spur Gear under Rolling Sliding Contact Conditions
Authors: Solomon, Tekeste
Advisors: Dr. Daniel Tilahun
Keywords: Nursing
Copyright: Oct-2011
Date Added: 3-May-2012
Publisher: AAU
Abstract: There are two main factors that affect the service life of gears: surface durability and tooth bending strength. Pitting and scoring is a phenomenon in which small particles are removed from the surface of the tooth due to the high contact stresses that are present between mating teeth. After the investigation of shot pinning to increase the tooth bending strength in gears, surface durability, in the form of macro and micropitting, is now considered the dominant restriction on gear life and performance. The main objective of this thesis is to develop a method for the investigation of surface fatigue in involute spur gears using finite element analysis. In achieving this two-dimensional & three- dimensional equivalent contacting cylinders to model involute spur gear in contact and three- dimensional model of involute spur gear is used. Modeling of involutes spur gear to study contact stress under different working conditions using CATIA & ANSYS software is done. In addition parametric study to investigate the effect of loading condition and material types in contact stress in gears, estimation of surface fatigue in rolling-sliding contact condition in spur gear by finite element method using ANSYS Workbench software, effect of initial surface roughness on surface fatigue is studied. The results obtained are compared with analytical method. Results from FEA using ANSYS show that, a 2D model, estimates accurately contact pressure and stresses bellow the contacting surface, where as the 3D Model estimate contact pressure with reasonable accuracy and failed to estimate stresses bellow the contacting surface. Results from ANSYS Workbench, for a 3D model of involute spur gear, shows that contact stress and shear stress results, correlated with theoretical formulation, with tolerable accuracy but, failed to estimate von-Mises stress with acceptable accuracy. Results from ANSYS Workbench, for a 3D model of equivalent contacting cylinders, show that contact stress, von-Mises stress and shear stress results, correlated with theoretical formulation, with tolerable accuracy. Finally, in estimating surface fatigue, this paper verified that, as the surface roughness increases the minimum fatigue life and the load caring capacity for a specific design life decreases.
URI: http://hdl.handle.net/123456789/2240
Appears in:Thesis - Mechanical Engineering

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