Compression of a soft sphere packing
Faculté des Sciences Hassan II Ben M'sick, Département de Physique, Boulevard
Idriss el Harti, Casablanca, Morocco
2 UMR 113, 2 Allée Képler, 77420 Champs sur Marne, France
Published online: 15 May 1999
Mechanical properties of packings of deformable spheres of polyelectrolyte gel are studied experimentally. These particles are plunged into a brine. They have the property to swell and shrink when the concentration of salt of the solution is varied. An oedometric compression is performed imposing cycles of deformation at constant speed and constant salinity Cs. Under many different conditions, we study the laws of deformation relating the macroscopic compression force F, to the macroscopic strain ε. We find empirical non linear relations of the type . The values of this exponent m are discussed and compared to the results of measurements on a single sphere compressed on a plane as well as to the results of experiments and simulations on dry model granular assemblies. The swelling and deswelling properties of the spheres are used to perform isotropic compression tests. In this situation we determine the relation between the force at equilibrium and the macroscopic strain . The results are compared with those obtained in the oedometric compression tests.
PACS: 81.40.Jj – Elasticity and anelasticity, stress-strain relations / 83.70.Fn – Granular solids / 82.70.Gg – Gels and sols
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999