Premium
Frequency, pressure, and strain dependence of nonlinear elasticity in Berea Sandstone
Author(s) -
Rivière Jacques,
Pimienta Lucas,
Scuderi Marco,
Candela Thibault,
Shokouhi Parisa,
Fortin Jérôme,
Schubnel Alexandre,
Marone Chris,
Johnson Paul A.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl068061
Subject(s) - nonlinear system , elasticity (physics) , harmonics , elastic modulus , amplitude , materials science , softening , mechanics , geotechnical engineering , mineralogy , physics , geology , optics , composite material , quantum mechanics , voltage
Acoustoelasticity measurements in a sample of room dry Berea sandstone are conducted at various loading frequencies to explore the transition between the quasi‐static ( f → 0 ) and dynamic (few kilohertz) nonlinear elastic response. We carry out these measurements at multiple confining pressures and perform a multivariate regression analysis to quantify the dependence of the harmonic content on strain amplitude, frequency, and pressure. The modulus softening (equivalent to the harmonic at 0 f ) increases by a factor 2–3 over 3 orders of magnitude increase in frequency. Harmonics at 2 f , 4 f , and 6 f exhibit similar behaviors. In contrast, the harmonic at 1 f appears frequency independent. This result corroborates previous studies showing that the nonlinear elasticity of rocks can be described with a minimum of two physical mechanisms. This study provides quantitative data that describes the rate dependency of nonlinear elasticity. These findings can be used to improve theories relating the macroscopic elastic response to microstructural features.