Study on structure optimization and vibration fatigue damage of wire bracket for rail vehicles.

• Extreme load and welding defects lead to fatigue failure of wire bracket. • The stress of the optimized wire bracket is reduced and the service life is increased. • Different forms of the same acceleration load have different effects on structural damage. • Vibration fatigue analysis based on safety factors can predict the fatigue life well. Fracture analysis and structure optimization of faulty wire bracket to improve service life. Bench tests and simulation analysis are carried out to evaluate the vibration fatigue damage of optimized structures. The failure reason for wire bracket is the synergistic effect of extreme load and welding defect and the optimized configuration demonstrates reduced stress and a protracted service lifespan. Multi-mode bench tests indicate that only the damage under on-track multiaxial load in time domain is greater than that of the on-track test, and there is a safety margin of at least 10 %. The damage of standard, frequency domain and uniaxial cumulative load are about 0.07, 0.46 and 0.45 times of the on-track test, respectively. The vibration fatigue analysis results show that the variance between the beach tests and simulation outcomes is below 20 %. The life of the wire bracket can be evaluated by vibration fatigue simulation with appropriate safety factor adjustments. [ABSTRACT FROM AUTHOR]