2-DIMENSIONAL SIMULATION OF DEHYDRATION OF A HIGHLY DEFORMABLE GEL - MOISTURE-CONTENT, STRESS AND STRAW FIELDS

A model taking into account the simultaneous influence of mechanical a nd hygrometric actions (Mrani and al., 1995a, 1995b) was applied to st udy of the dehydration of a cylinder of highly deformable biphase gel (agar gel) (Mrani and al., 1995b). Numerical solution of the water tra nsport equation and the mechanical equilibrium equation provided acces s to the water content and stresses and strains in the cylinder. The n umerical results were validated for water content and overall deformat ion of gel cylinders. The model clearly shows the inversion of the cur ve of the faces of the cylinder observed experimentally. Three deforma tion phases were observed. In the first phase, when the concaveness of the faces of the cylinder was turned inwards, tractive stress appeare d at the surface of the sample. More uniform distribution of the water content became established in a second phase and the cylinder recover ed its initial shape corresponding to the relaxation of the stress sta te. In the third phase, the concaveness of the faces of the cylinder w as turned outwards, the surface became rigid with compression at the s urface and traction in the centre.