Finite strain swelling induced bending in bilayer gels: semi-analytical and numerical approaches

The accurate and efficient design of the bilayer sensors and actuators made of hydrogels are of crucial importance. In this work, a semi-analytical method is developed to solve the swelling induced bending of hydrogel bilayer under plane strain condition. The bilayer consists of a neutral incompressible elastomer layer attached to a hydrogel layer. The interface of two layers is assumed to be perfectly bonded. Moreover, the plotted problem is simulated using Finite Element Method (FEM) employing UHYPER subroutine in ABAQUS software. Several cases are solved to demonstrate the validity and performance of the proposed semi-analytical method. A good correspondence between the presented method and the finite element method is observed. The deformation and the stresses inside the layers are presented for various material parameters employing both the developed semi-analytical formulation as well as the finite element method. Finally, the effect of density of cross-link in hydrogel polymer network on curvature is also investigated.