THE LONG PERIOD DAMPING CAPACITY OF THIN WIRES IN TORSION,
Abstract
This research investigates the torsional damping capacity of thin wires subject to long period forced oscillation. Because the periods of interest are in the order of 10 hours, the direct measurement of damping capacity is impossible. It is shown that since internal friction is a manifestation of material anelasticity, Boltzmann's Superposition Theory can be used to develop a functional relation correlating internal friction and creep. The damping capacity of several high loss wires is determined directly by (a) measuring the logarithmic decrement during one hour period free vibration and (b) measuring the deformation response phase lag during one hour period forced vibration. These values are compared to predictions derived from the creep - damping function utilizing measured creep data. On the basis of the correlation obtained, a curve of internal friction versus period of oscillation is generated. The mechanism of internal friction is attributed to viscous damping at the cadmium grain boundaries and dislocation effects. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1964
- Accession Number
- AD0608165
Entities
People
- Barry E. Tossman
Organizations
- Johns Hopkins University Applied Physics Laboratory