Pulse excitation of railway wheels

A review is given of current applications of acoustic principles to testing and performance evaluation of railroad equipment. Also, a brief review is given of previous knowledge of the propagation of dispersive pulses in waveguides. An experimental investigation has been made of pulses propagating in a plate, a ring of rectangular cross section and in a model railway wheel. Pulses of a single frequency are produced at a point on the outer circumferential surface of each test piece and are received at other points along its periphery. Records of pulse arrivals are made by photographing the oscilloscope trace with a Polaroid camera. Experimental results show that pulses originating from a small source on the rim of the model railway wheel propagate directly through the wheel and also through the interior and on the surface of the rim. The behavior of these pulses is shown to be in accordance with the predicted propagation of Lamb waves in the plate region of the wheel and the predicted propagation of Morse waves in the rim of the wheel.