Implications of the similarity principle relating creep and attenuation in finely grained solids

[摘要] The Raj-Ashby model of diffusionally accommodated grain-boundary sliding implies the existence of similitude in the mechanical loss spectrum of finely grained solids: the quality factor Q of a shear wave propagating with angular frequency omega is related to the viscosity eta for steady-state Coble creep and the (unrelaxed) rigidity mu through a dimensionless relation of the form Q = F(omega eta/mu). Using existing measurements of eta and Q obtained respectively from uniaxial creep tests, and forced torsional oscillation tests, we test that prediction. Though the similarity principle appears to hold, definitive proof will require further measurements of Q and eta over a larger range of grain sizes. With that proviso, we conclude that the Raj-Ashby model includes the basic physical mechanisms acting in the experiments underlying two existing data sets on attenuation in the geological material olivine. (C) 2009 Elsevier B.V. All rights reserved.

[发布日期] 2009-09-25

[效力级别]  Proceedings Paper

[关键词] Grain boundary sliding;Mechanical spectroscopy;Grain boundaries;Dimensional analysis;Similitude