THE GENERATION OF BENDING VIBRATIONS IN DRILL RODS
One important source of noise from percussive rock drills is bending vibrations of the drill rod. These vibrations originate from imperfect rotational symmetry in the system. It is possible to improve symmetry at the machine end by means of tight fittings and small tolerances. It is, however, difficult to improve the conditions at the rock end of the rod. This paper presents a theoretical investigation of how much of the energy fed into the system that can be expected to be converted to bending energy in the drill rod. The model considered is simple, an integral steel with the rock response represented by an eccentrically acting viscous damper, but it is believed to give qualitively correct answers. The results indicate that in a typical situation, one can expect about 10% of the incident stress wave energy to be converted to bending. For a system with a detachable drill bit the fraction is probably less. The form of the incident stress wave is not important, although a steep front tends to give more bending. A heavier piston reduces the bending fraction. (Author/TRRL)
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/issn/00207624
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Corporate Authors:
Pergamon Press, Incorporated
Headington Hill Hall
Oxford OX30BW, -
Authors:
- Carlvik, I
- Publication Date: 1981-4
Media Info
- Features: Figures; References;
- Pagination: p. 167-172
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Serial:
- International Journal of Rock Mechanics and Mining Science
- Volume: 18
- Issue Number: 2
- Publisher: Pergamon Press, Incorporated
- ISSN: 0020-7624
Subject/Index Terms
- TRT Terms: Bending; Drilling; Energy; Equipment; Mathematical models; Pistons; Rock drilling; Rocks; Rods; Sound; Stresses; Symmetry; Vibration
- Old TRIS Terms: Rock drills
- Subject Areas: Bridges and other structures; Construction; Energy; Geotechnology; Highways; Vehicles and Equipment; I43: Rock Mechanics; I54: Construction of Tunnels;
Filing Info
- Accession Number: 00342350
- Record Type: Publication
- Source Agency: Transport Research Laboratory
- Files: ITRD, TRIS
- Created Date: Dec 22 1982 12:00AM