Three-dimensional dynamic simulation of elastocapillarity

At small scales, the interaction of multicomponent fluids and solids can be dominated by capillary forces giving rise to elastocapillarity. Surface tension may deform or even collapse slender structures and thus, cause important damage in microelectromechanical systems. However, under control, elastocapillarity could be used as a fabrication technique for the design of new materials and structures. Here, we propose a computational model for elastocapillarity that couples nonlinear hyperelastic solids with two-component immiscible fluids described by the Navier-Stokes-Cahn-Hilliard equations. As fluid-structure interaction computational technique, we employ a boundary-fitted approach. For the spatial discretization of the problem we adopt a NURBS-based isogeometric analysis methodology. A strongly-coupled algorithm is proposed for the solution of the problem. The potential of this model is illustrated by solving several numerical examples, including, capillary origami, the static wetting of soft substrates, the deformation of micropillars and the three dimensional wrapping of a liquid droplet.