1. Agreed assumptions

Certain assumptions necessary for this theory have been discussed or adopted. We will assume :

• that the response to a mechanical load does not depend on the hydrostatic pressure p (§ 2.2 of the file [42] );

• that the material is isotropic, which means that its mechanical properties are independent of the direction of loading;

• that its behavior is the same when the stress state σ is changed to - σ (an assumption already adopted to interpret the bending test in § 3.2 of the [42] file);

• that it obeys Hill's maximum workload principle [30]