Fatigue analysis and lifespan prediction of the recirculating planetary roller screw mechanism

A finite element model of the transmission mechanism is established to investigate the random vibration fatigue characteristics of the recirculating planetary roller screw mechanism (PRSM) in a specific parameter configuration, based on fatigue failure theory. The dynamic analysis and fatigue life prediction are conducted using fatigue analysis, incorporating the S–N curve of the material and Miner’s linear damage accumulation theory. Four fatigue lifespan prediction models are utilized to compare the analytical solutions with simulated damage. Findings reveal that the resonance induced by the recirculating PRSM at 4080 Hz causes the most significant damage to its structure. When the excitation frequency remains the same, the maximum contact stress areas and the minimum fatigue life remain consistent. Furthermore, the frequencies corresponding to the peak stress in the harmonic response analysis align with those of the peak power spectral density in the fatigue analysis of the recirculating PRSM. Additionally, under the same damping ratio but different load conditions, the stress range of the recirculating PRSM decreases as the load decreases. When considering various damping ratios under identical load conditions, higher damping ratios result in higher stress amplitudes concentrated in the low-stress range of the recirculating PRSM. The results obtained from this study offer a theoretical guidance for designing fatigue optimization approaches and accelerate test methods for the recirculating PRSM.