Application of Dislocation Theory to Internal Friction Phenomena at High Frequencies

TLDR

The paper reviews 15 years of data on damping of mechanical vibrations in the kilocycle and megacycle range, and can be read independently of the earlier theory development. The authors suggest a series of new experiments that may allow stronger conclusions to be drawn. They compare how the decrement and modulus change depend on frequency, strain amplitude, and other parameters with predictions from a previously developed dislocation theory. While general agreement and several quantitative results are obtained, the theory cannot be said to agree everywhere because some necessary parameters are not yet well known.

Abstract

A detailed discussion of data obtained over the past 15 years concerning the damping of mechanical vibrations in the kilocycle and megacycle range is given. The dependence of the decrement and modulus change on the variables of frequency and strain-amplitude and many other parameters is compared with predictions of the dislocation theory developed in an earlier paper. Although general agreement is obtained, and many interesting quantitative results are found, it is not possible to say that the theory agrees everywhere since not all the necessary parameters are known well enough theoretically. A number of new experiments are suggested which may permit stronger conclusions to be made. This part may be read independently of the earlier paper by the reader who does not wish to follow the development of the theory in detail.