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Percussive Force Magnitude in PermafrostAn in-depth look at percussive drilling shows that the transmission efficiency is very important; however, data for percussive drilling in hard rock or permafrost is rarely available or the existing data are very old. Transmission efficiency can be used as a measurement of the transmission of the energy in the piston to the drill steel or bit and from the bit to the rock. Having a plane and centralized impact of the piston on the drill steel can optimize the transmission efficiency from the piston to the drill steel. A transmission efficiency of near 100% between piston and drill steel is possible. The transmission efficiency between bit and rock is dependent upon the interaction within the entire system. The main factors influencing this transmission efficiency are the contact area between cutting structure and surrounding rock (energy loss due to friction heat), damping characteristics of the surrounding rock (energy dampening), and cuttings transport. Some of these parameters are not controllable. To solve the existing void regarding available drilling data, an experiment for gathering energy data in permafrost for percussive drilling was designed. Fifteen artificial permafrost samples were prepared. The samples differed in the grain size distribution to observe a possible influence of the grain size distribution on the drilling performance. The samples were then manually penetrated (with a sledge-hammer) with two different spikes.
Document ID
20010001664
Acquisition Source
Jet Propulsion Laboratory
Document Type
Conference Paper
Authors
Eustes, A. W., III
(Colorado School of Mines Golden, CO United States)
Bridgford, E.
(Colorado School of Mines Golden, CO United States)
Tischler, A.
(Colorado School of Mines Golden, CO United States)
Wilcox, B. H.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Date Acquired
August 20, 2013
Publication Date
January 1, 2000
Publication Information
Publication: Space Resources Roundtable II
Subject Category
Geophysics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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