Development of a Quiet Rock Drill. Volume 2. Sources of Drill Rod Noise.

摘要

The report describes how longitudinal and bending stress waves in percussive drill rods generate noise. It is shown that in practical drills the largest noise source is the bending waves,which are mainly generated because of imperfections in the piston,chuck,and drill rod alignment. Equations are presented which enable the noise spectra generated by the bending and longitudinal waves to be precisely predicted. Means for reducing the amplitude of the bending waves are discussed.