Description of Physically Nonlinear Elasticity of Granular Materials.

The properties of simple (i. e. , tensorially linear) physically nonlinear relations describing the elastic properties of granular materials are illustrated. On the basis of the conditions of integrability and potentiality of these relations, a study is made of the differences occurring in different methods of formulating them. It is shown that, in general, the known relations for granular materials do not describe purely elastic effects. These relations can only apply to the first unloading. On the other hand, many nonlinear effects of elastic character cannot be described in the small strain range by tensorially linear relations.