Detection of Flaws in Railroad Wheels Using Acoustic Signatures

A system for automatic inspection of railroad wheels using acoustic signatures is proposed. There is a discussion of the types of defects which need to be found. The main components of a system are then outlined. It is concluded that impact is the best way to excite the wheel into vibration because of the rich spectrum of resonances generated. Detection of sound radiated into the air by a microphone is the best way to obtain the acoustic signature for finding cracks in the rim or plate, but flat spots or shattered rims are best detected with an accelerometer mounted on the rail. Methods of processing the signals from the detection transducers are then examined. Finally some preliminary laboratory and field tests of such systems are described.