It is shown theoretically that there should be a frequency dependence of the velocity of a Rayleigh wave propagated along the edge of a thin plate. This velocity can be expressed in terms of an effective Poisson's ratio, of which the pseudo Poisson's ratio of Oliver, Press and Ewing (1954) is a special case. Rayleigh waves have been generated and detected on the edge of a metal disc. Results from the apparatus show that the velocity shift of the Rayleigh wave is very much smaller than expected over the frequency range used. The measured velocities are corrected for the curved propagation path. The velocity deviation occurs at the frequency where the theoretical value begins to show a rapid change, i.e. where the effective Poisson's ratio should become negative. The discrepancies between the theoretical and experimental values for the Rayleigh wave velocities are explained, and the elastic constants of the material in which propagation occurs (brass 60% Cu. 40% zn.) calculated for a temperature of 220 C.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:623125 |
| Date | January 1968 |
| Creators | Sinclair, Rex |
| Publisher | Imperial College London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10044/1/16082 |
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