Accelerated life testing for freight railcar systems based on damage compression and excitation reconstruction: method and application

Fatigue failure threatens the structural reliability of freight railcars. Conventional multi-body system (MBS)-based life testing (LT) suffers from long durations, high costs, and premature sub-component failures that affect car body responses. To address these limitations, this study proposes a car body system (CBS)-based accelerated life testing (ALT) method. It integrates an excitation-damage-compression (EDC) method to compress the AAR lv.5 track irregularity spectrum and an equivalent excitation reconstruction (EER) model enabling CBS to replicate MBS responses. Testing on a lockbolted container flatcar using full-scale benches and 12 time-frequency metrics indicates an 87.96% reduction in duration (8.02E+03 h) compared to MBS-LT (6.67E+04 h) for 1.0E+06 km equivalent mileage. The method maintains damage retention satisfying engineering requirements and prevents response deviations caused by sub-component failures. This study provides an efficient fatigue assessment solution for freight railcars, demonstrating significant engineering application value.