engleski

Bending fatigue crack initiation life prediction in spur gear tooth root

Numerical model for bending fatigue crack initiation life prediction in spur gear tooth root is presented. Stresses are determined from two-dimensional finite element model, assuming plane stress conditions. The material, case carburized 14NiCrMo13-4 steel, is assumed to be homogenous, isotropic and linear elastic. Neuber’s rule is used to account plasticity effects. The bending fatigue crack initiation life is predicted using a strain-life approach including: surface finish, mean stress and residual stress effects. Assuming that fatigue cracks are initiated on a component’s surface, analysis is performed for all the nodes in the root fillet of the loaded tooth side. Node with the smallest life is regarded as location of potential crack initiation. Two load cases are investigated: the first one in which gear tooth is loaded with a normal cyclic load acting at the highest point of single tooth contact, and the second one in which actual gear operation is considered.

spur gear; bending fatigue; crack initiation; strain-life approach; case carburized steel

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