FUNDAMENTAL STUDY ON FRICTIONAL NOISE - 5. THE INFLUENCE OF RANDOM SURFACE ROUGHNESS ON FRICTIONAL NOISE

Abstract

Frictional noises which occur when a steel rod is pressed in the radial direction on a rotating thick steel disk with various random surfaces without lubrication are studied experimentally and theoretically. When the surface roughness becomes larger, loss of contact occurs. The results calculated by considering the random surface roughness as an external force agree with the experimental results. Assuming a rod as a sound radiator of cylindrical waves, the calculated conversion ratio from acceleration of a rod to sound pressure is coincident with the experimental results. Additionally, sound pressure level is proportional to the differentiation of lateral acceleration of the rod. This conversion ratio makes it possible to predict the sound pressure level from the easily measured acceleration.