Research on the structural strength of medium and low speed maglev vehicle levitation frame based on full-scale test bench

The structural strength of the levitation frame is crucial for the safe operation of medium and low speed maglev vehicle. This paper integrates theoretical calculations, dynamic simulations, and finite element analysis (FEA) to determine levitation frame boundary loads, identify weak points, and calculate cumulative damage. A full-scale strength test bench was constructed, and static and fatigue strengths were evaluated using the Fourth Strength Theory and a modified Goodman-Smith (GS) diagram, validated through fatigue tests and non-destructive testing. Results show that under emergency landing brake conditions, the peak stress at the parking brake skid is 67.22 MPa, below the material’s yield limit; high stresses are mainly concentrated in conditions with smaller load-bearing contact areas. Stress analysis indicates that stress amplitude and mean stress are distributed in the central region of the GS diagram, with stress amplitude having a significant impact, revealing the important influence of dynamic loads on fatigue strength. Good agreement is observed between critical areas and stress distributions from FEA and bench tests. Cumulative damage analysis shows higher damage in weld areas than in base material, with a maximum cumulative damage of 0.19 at the traction rod seat fillet weld. Non-destructive testing after fatigue tests found no cracks. These results validate the effectiveness and accuracy of the method presented in this study.