Fatigue Crack Identification in Weld Zone of Bogie Using Guided Wave

Abstract

As one of the most convenient means of urban and intercity public transportation, rail train has been developed rapidly in recent years. The bogie is an important structure of rail train, transmitting the traction, braking force, lateral force and vertical force during the traction operation. With the development of high speed and heavy load, the appearance of fatigue cracks in rail train bogies is increasing, which reduces the driving life of rail train and even causes serious traffic accidents. Real-time monitoring on the integrity of bogie is an inevitable requirement for ensuring the safe operation of rail train. Guided wave based active structural health monitoring was developed to identify the fatigue crack of the bogie frame in this paper. Experiments were conducted on a welded T shape specimen with thickness of 12mm. 10 PZTs were mounted around the weld zone of specimen, five of them were used as actuators, and the other five PZTs were used as sensors. Five-peak modulation narrow-band sine waves were used as the exciting signals. From the sensor signals, the advanced Damage Index (DI) was employed to identify the propagation of crack. The experimental results demonstrate that the size of crack damage as small as 2mm around the weld on the bogie frame can be successfully detected.