Linear models of dissipation whose Q is almost frequency independent

摘要: Laboratory experiments and field observations indicate that tlie Q of many non ferromagnetic inorganic solids is almost frequency independent in the range 10' to 10~2 cps; although no single substance has been investigated over entire spectrum. One purposes this investigation find analytic expression a linear dissipative mechanism whose large ranges. This will be obtained by introducing fractional derivatives stress strain relation. Since aim research also contribute elucidating dissipating earth free modes, we shall treat cases dissipation purely torsional modes shell radial vibration solid sphere. The theory checked with new values determined for spheroidal between 10 5 minutes integrated Railegh waves 0.6 minutes. Another check made experimental longitudinal an alluminimi rod, 10-5 10-3 seconds. In both clicks represents observed phenomena very satisfactory.