Ricerc@Sapienza

This paper investigates swelling-induced eversion and flattening in curved bilayer gel beams. An explicit formula is produced to evaluate the change in curvature induced by large swelling deformations. The validity is tested against a fully coupled nonlinear three–dimensional stress-diffusion model. Limit situations for nearly-homogeneous and slightly curved beams are discussed.

In active gels, liquid redistribution, network deformation and material remodeling due to bulk activation, mimicking the presence of molecular motors, are strongly coupled. We present a consistent mathematical model capable to gain a deep understanding of the phenomenon in both steady and transient conditions. With explicit reference to active gel spheres, we evidence the role that not uniform bulk activation may have in generating local stress or strain actuators based on liquid redistribution.

Polymer gels are porous fluid-saturated materials which can swell or shrink triggered by various stimuli. The swelling/shrinking-induced deformation can generate large stresses which may lead to the failure of the material. In the present research, a nonlinear stress–diffusion model is employed to investigate the stress and the deformation state arising in hydrated constrained polymer gels when subject to a varying chemical potential. Two different constraint configurations are taken into account: (i) elastic constraint along the thickness direction and (ii) plane elastic constraint.