Reliability Prediction Model for Ball Screws Considering Full-Life Fatigue Damage

This paper addresses the challenges of life prediction and reliability assessment for ball screws under complex operating conditions by proposing a reliability prediction model that incorporates full-life fatigue damage. First, a full-life fatigue life prediction model encompassing the three stages of crack initiation, propagation, and fatigue cumulative spalling is developed. This model comprehensively considers the effects of material properties, geometric parameters, and loading history, enabling a systematic description of the fatigue process of ball screws from initial use to final failure. Based on this life prediction model, an enhanced adaptive Kriging–Monte Carlo simulation (E-AK-MCS) method is introduced to construct a surrogate model, which efficiently solves the high-dimensional nonlinear limit state function, thereby enabling accurate reliability assessment and parameter sensitivity analysis. Experimental results demonstrate that the proposed model achieves an average life prediction accuracy of 94.15% for the 8020 and 5005 specification ball screws, indicating its preliminary engineering applicability under the tested conditions. Reliability analysis indicates that ball diameter fracture toughness, and initial crack size are key factors influencing service reliability. This research provides systematic theoretical methods and technical support for the accurate life prediction, reliability design, and process optimization of ball screws.