2D and 3D Numerical Investigation of Delrin Spur Gear

Delrin gears are used in light and medium-duty engineering applications. Such gears are subjected to Hertzian contact stress due to the non-conformal contact nature. The contact stress is majorly influenced by the directional stresses (σx, σy, and τxy) during their engagement and also significantly affected by the face width of the gear. ANSYS is one of the widely used Finite Element Analysis (FEA) tool to determine the behaviour of contact stress of those gears. Even though numerous 2D and 3D FEA investigations were performed to determine the gear contact stress behaviour, the occurrence of surface and subsurface stresses was not explored especially for Delrin gears. Thus, the work attempted to study the surface and subsurface contact stress of the 2D (plane stress with 1 mm thickness condition) and 3D gear pair using ANSYS APDL. The optimum mesh sizes were selected from the convergence study, and further simulations were performed. From the analysis, the maximum stress was observed at the contact surface for 2D analysis, whereas, 3D analysis showed the maximum stress at a depth of 0.12 mm below the contact surface (subsurface stress). Almost similar trend was observed for the X-directional normalized stresses, whereas Y and XY-directional normalized stresses showed a deviation of 27 and 45% respectively during the 2D and 3D gear pair analysis. The variation in contact stresses along the different consecutive face-width planes causes the Y and XY-directional stress deviations.