Life and damage mode modeling applied to plastic gears

•New approach is proposed to model gears failures.•All major factors for the gear damage are considered in the model.•The model determines the most important failure mode for an operating condition.•The model is valid for plastic gears.•Optimum operating point is found for a greater gear life span.

There is a need to correctly dimension gears for an application with an understanding of how the gear will deteriorate until final failure. However, this task has been difficult because engineers must consider the complexity of gear meshing phenomena combined with the gear material-specific properties and application particularities to determine the critical failure and maintenance points. This article provides a review of the multiple damage modes of plastic gears, including both general and plastic gear-exclusive modes.This article reviews the different branches of the damage problem, performs a combined solution of finite element analysis (FEA) and validated analytical equations for plastic gears. With this knowledge, a unique system of analysis of gear utilization perspectives that evaluates all possible damaging processes is built.By applying a range of normal loads on a plastic gear, it was verified that the damage mode depends highly on the applied load. The identification of the proper damage mode allows preventive actions to be taken because the limits of plastic gears and the optimal usage are identified. With this damage modeling strategy, the designer can skip several steps in reaching a decision regarding plastic gear applicability. This synthesis represents significant progress for plastic gear damage modeling because the major factors of plastic gear functioning and the damage factors are observed.