On the nature of idling noise of circular saw blades.
Reiter-WF Jr.; Keltie-RF
J Sound Vib 1976 Jan; 44(4):531-543
The characteristics of noise produced by idling circular saw blades were discussed. Noise produced by idling saw blades arises from the vibrating surface of the rotating saw disk (vibration noise) and the rotating disk interacting with the fluid medium (aerodynamic noise). The mechanisms for vibration and aerodynamic noise are unrelated. Studies directed at establishing relationships between saw blade parameters and generation of aerodynamic noise were summarized. These have shown that the sound power generated varies between the 5.0 and 5.5 power of the blade tip speed. Changing gullet size, shape, back angle, blade thickness, and the number of teeth usually causes sound level changes of less than 6 decibels. The aerodynamic sound spectrum is broad based in character and is primarily a function of blade tip speed and thickness. In the case of carbide tipped blades, the sound spectrum also depends on the thickness of the carbide tip. The intensity of the radiated sound increases with the number of teeth when the pitch length/gullet diameter ratio is larger than 4.5. It decreases with increasing number of teeth when the ratio is less than 4.5. The authors suggest that the dominant acoustic sources responsible for the idling noise produced by circular saw blades are dipolar in nature. The dipoles result from the unsteady pressure fluctuations produced by the teeth passing through the separated air streams present in the gullets.
NIOSH-Publication; NIOSH-Grant; Noise-induced-hearing-loss; Occupational-exposure; Laboratory-testing; Noise-exposure; Industrial-equipment; Noise-sources; Noise-transmission; Noise-analysis
Mechanical and Aerospace Engr North Carolina State Univ 3182 Broughton Hall Raleigh, N C 27607
Journal of Sound and Vibration
North Carolina State University Raleigh, Raleigh, North Carolina