Evaluation of stress risers severity in spur gears meshing

The standards for gears design use the maximum value of the normal stress sigma(zz), depicted sigma(H), as critical stress for RCF of gears. This value sigma(H) can't sustain evidences regarding the stress risers influences. The paper uses the von Mises stress sigma(vM) as critical stress responsible for the initiation of RCF. For concentrated contacts analyses the drawback of FEM is the very long computing time and therefore the author used a semi-analytical method (SAM) based on the numerical formulation for the involved equations of linear half-space theory. The finite width of gears' teeth imposes quarter-space limitations and consequently the virtual pressures and correction coefficient were considered in the iterative process for pressures distribution. The pressure distribution was further used to evaluate the stress tensor components and 3D distributions of von Mises stresses. Examples are presented for spur gears with different values for end chamfers.