The influence of line types and operating conditions on structural fatigue of bogie frame in the quasi-high-speed train: an experimental study

Abstract

The operational condition of the quasi-high speed train is more complex than that of a high-speed train. It is essential to investigate the distinctive damage characteristics of the bogie during the operation of diverse line types. This paper obtains the dynamic stress at key positions through the measurement of the bogie frame and analyzes the characteristics under different service conditions. The results show that the impact excitation of the track had the most significant influence on the structural damage of the bogie frame, which could cause more than 50% of the total damage. The weld at the locating node of the axle box is the most affected by rail-wheel impact, with the damage increasing by 2.3 times. When running on the existing line, the damage caused by the braking load on the weld at the joint of transverse beam and longitudinal beam, the weld at the joint of transverse beam and longitudinal beam is nearly five times greater than that at uniform speed. Furthermore, the damage of the weld at the joint of transverse beam and longitudinal beam and the weld at the joint of transverse beam and side beam has an increase of more than 24% with the decrease of the curve radius. The radius of the high-speed line has a minimal increase influence on the damage to the weld at the locating node of the axle box. The majority of the damage to the structure is attributable to excitation below 150 Hz, with a cumulative damage in this frequency range exceeding 80%. The characteristics of the dynamic stress distribution satisfy the combined distribution of the Weibull distribution and logarithm normal distribution. The frequency range corresponding to 70% of the total damage at each measurement point is wider on the existing line than the high-speed line.