The Effect Of Friction On Gear Crack Characteristics

Under the Natural Science Foundation of Gansu Province and the fund of academic step & characteristic study of Lanzhou University of Technology. Gear tooth root crack fracture mechanics characteristics and crack tip stress intensity factor calculation method were studied based on fracture mechanics theory. The effect of friction and structural parameters on gear crack characteristics which is the theoretical foundation of the damage tolerance design and determine the residual life were analysed.The tooth root fracture were studied by FEM from the point of view of fracture mechanics. The meshing gears and gear roots crack model were created by ANSYS with bottom-up modeling. The steel gear friction coefficient were given by someone after a large number of experiments:f=0.03-0.04. In this Master's thesis f=0.03, 0.032, 0.034, 0.036, 0.038, 0.04.The singularity of crack tip was considered and the effects of friction coefficient (including f=0) and crack shape (0≤a/c≤1)on equivalent stress, displacement and stress intensity factor of the crack tip were analyzed by ANSYS. It was calculated when a/c = 0 by ALGOR software.The results showed that:(1) The crack tip equivalent stress are increased with the friction coefficient, the crack tip stress intensity factor,the crack tip displacement increases in the same structure.(2) The crack tip equivalent stress have a volatility change with the same friction coefficient in different structural parameters, when a=0.067B shear stress reach max.(3) With the changing of a/c, the former surface play a major effects under a/5 <0. 05, and the after surface play a major effects under a/B>0.05. Along with the increasing of specific value the stress intensity factor first increased and then decreased.(4) When f=0 when the crack tip stress and displacement,stress intensity factor is very small which illustrate the importance of the study.(5) The risk of cross-section thickness of gear can be simpled to:...