Materials and structures vol:37 issue:268 pages:271-280
The non-linear quasi-static and dynamic elastic behaviour of Berea sandstone has been experimentally analysed showing hysteresis and a strong influence of moisture especially in the lower saturation range. It is shown that non-linear hysteretic response originates within the "bond system" of the material, that includes micro-cracks, intergrain contacts, asperities, dislocations,... Hysteresis or non-classical non-linear behaviour is explained by the fact that the defects do not open and close at the same pressure. In dynamic loading a small number of these defects are activated explaining the higher stiffness compared to quasi-static loading, where a lot of defects are closed or opened. These effects can be adequately described in the framework of the so-called P-M (Preisach - Mayergoyz) space model.