Dynamic reliability analysis for planetary gear system in shearer mechanisms

Abstract The paper considers the reliability and reliability-based sensitivity analyses of planetary gear systems in shearer mechanisms. It is important to quantify the dynamic performance of planetary gear system to aid in risk assessment and risk mitigation of the shearer mechanism. Failure of the system is defined as the dynamic contact stress exceeding the material strength within a time period. It is necessary to evaluate the cumulative failure event, which is defined as the combination of failure events at each time point. The method of saddle-point approximation (SPA) is introduced to evaluate the probability distribution of the equivalent maximum contract stress for the planetary gearbox. Additionally, reliability-based sensitivity indices are derived to investigate the parametric significance of random input variables. The gear transmission system of traction unit is used to demonstrate the engineering applications of the proposed method for dynamic reliability and reliability-based sensitivity analyses. A crude Monte Carlo simulation is performed to provide benchmark results. The results indicate that the structural parameters of the sun gear have more of an influence on system reliability than other parts of the mechanism.