Finite bending of a temperature-sensitive hydrogel tri-layer: An analytical and finite element analysis

Layered hydrogel structures have been utilized to design sensors, actuators, and switches for various applications. In this article, we introduce a new design concept of a tri-layer composed of a positive and a negative temperature-responsive hydrogels layers attached to an elastomeric layer. This structure is capable of bi-directional bending while maintaining high strength and stiffness. Then, swelling-induced finite bending of the tri-layer is studied both analytically and numerically (finite element method). The analytical method developed in this work is a novel method which is in a very good agreement with the finite element method results both for the deformation and the stress fields. Finally, several parametric studies are conducted to investigate various material and geometrical parameters effects on the deformation and the stress fields. The obtained results can be used in the tri-layer design and applications.