Finite element stress analysis of a generic spur gear tooth

The prediction of bending stresses in a gear tooth, resulting from an externally applied torque, requires special consideration when designing spur gear systems. The tooth geometry is such that stress risers exist which must be accounted for when determining stresses. In addition, variables affecting the exact load point on the tooth and the direction of the applied load are critical. The presented study attempts to provide an acceptable alternative analysis approach to the procedure described in the American Gear Manufacturers Association (AGMA) standards. An interactive preprocessor was developed which generates all the output information, including a detailed tooth profile, necessary to perform a finite element bending stress analysis of the gear system. To validate the procedure, a test group of spur gear systems was identified and analyzed. The results were compared to those obtained from the AGMA standards. The comparison revealed the finite element stresses to be slightly more conservative than the corresponding AGMA standard stresses. A new generalized bending stress equation and geometry factor, based on the finite element approach, was also introduced.