Rating of Spur Gear Strength Using Photoelasticity and the Finite Element Method

Problem statement: Toothed gears are some of the most used machine elements for motion and power transmission between rotating shafts. This fact induces the need for improved reliability and higher endurance, which require precise and clear knowledge of the gear tooth stress field during meshing. Approach: This study considered the calculation of maximum stress at gear tooth root when the meshing gears are loaded at their most unfavorable contact point (highest point of single-tooth contact-HPSTC), using both numerical and experimental methods. Finite Element Method (FEM) is used for the numerical stress analysis and photoelasticity is applied for the experimental investigation of the stress field. Results: The experimental results of the maximum dimensionless stress derived from the photoelasticity experiments are compared to the respective theoretical stress results of the finite element analysis. Conclusion: It was found that the deviation between the results of the applied methods falls between reasonable limits whereas it rises with increasing number of teeth of the large gear.