Linear models of dissipation whose Q is almost frequency independent
Laboratory experiments and field observations indicate<br />that tlie Q of many non ferromagnetic inorganic solids is almost frequency<br />independent in the range 10' to 10~2 cps; although no single substance has<br />been investigated over the entire...
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| Format: | Article |
| Language: | English |
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Istituto Nazionale di Geofisica e Vulcanologia (INGV)
1966-06-01
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| Series: | Annals of Geophysics |
| Online Access: | http://www.annalsofgeophysics.eu/index.php/annals/article/view/5051 |
| Summary: | Laboratory experiments and field observations indicate<br />that tlie Q of many non ferromagnetic inorganic solids is almost frequency<br />independent in the range 10' to 10~2 cps; although no single substance has<br />been investigated over the entire frequency spectrum. One of the purposes<br />of this investigation is to find the analytic expression of a linear dissipative<br />mechanism whose Q is almost frequency independent over large frequency<br />ranges. This will be obtained by introducing fractional derivatives in the<br />stress strain relation.<br />Since the aim of this research is to also contribute to elucidating the<br />dissipating mechanism in the earth free modes, we shall treat the cases of<br />dissipation in the free purely torsional modes of a shell and the purely<br />radial vibration of a solid sphere.<br />The theory is checked with the new values determined for the Q of<br />the spheroidal free modes of the earth in the range between 10 and 5 minutes<br />integrated with the Q of the Railegh waves in the range between 5 and 0.6<br />minutes.<br />Another check of the theory is made with the experimental values<br />of the Q of the longitudinal waves in an alluminimi rod, in the range between<br />10-5 and 10-3 seconds.<br />In both clicks the theory represents the observed phenomena very<br />satisfactory. |
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| ISSN: | 1593-5213 2037-416X |