Studies on Internal Friction and Vibration Fatigue
Abstract
The facts established by the above research are as follows: that the f'-f curves of metals, as determined by the methods described, show critical points in certain cases, which are to be identified with changes in properties of the metal unrevealed by other tests. That there is in many cases a certain limiting stress f subscript one, below which repetitions of stress produce no effect on the metal whatsoever. That there is another and higher limiting stress f subscript two, above which repetitions of stress cause general increase of internal friction accompanied by plastic deformation and will ultimately lead to failure. That stress-ranges laying between the stresses f subscript one and f subscript two produce changes in the metal of such a kind as to increase the value of f subscript one up to the stress-range, which is acting on the metal, thus decreasing its internal friction in that range and apparently producing beneficial effects rather than that reverse. That with regard to vibrations superposed on static loads, the simple f'-f curve gives no answer; but that a modified apparatus can be made to yield the required information. That highly cold-worked materials yield f'-f curve that are steeper, i.e., show more internal friction than heat-treated materials, in the useful stress-ranges. It is the opinion on the Laboratory that the apparatus and methods here described are capable of being used to study a property of metals which is not measured or revealed by other tests, and possesses many possibilities.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 28, 1934
- Accession Number
- AD1145256
Entities
People
- R. H. Canfield
Organizations
- United States Naval Research Laboratory