On buckling of a soft incompressible electroactive hollow cylinder

Soft electroactive materials show great potential for device and robot applications. However, these materials are apt to experience buckling and pull-in instability under critical pressure or voltage, and, therefore, their practical applications are more or less prevented. In this paper, buckling behavior of incompressible soft electroactive hollow cylinders is investigated based on the nonlinear theory of electroelasticity and the associated linear incremental field theory. Hollow cylinders including or excluding the effects of exterior electric field are studied in a comparison manner. The equations governing the linearized incremental motion upon a finitely deformed configuration in the presence of an electric field are derived and exactly solved by introducing three displacement functions. As an illustrative example, the generic isotropic electroactive materials are considered and results are presented for a simple model of ideal electroelastic material. Numerical calculations show that the buckling of electroactive hollow cylinders is significantly influenced by the biasing fields, the electromechanical coupling parameters, the geometrical parameters of the cylinder, and the electric field outside the cylinder. In particular, a phase diagram is constructed based on the numerical results to clearly identify the dominant buckling modes and the transition between them in the κ−−ν (axial wave number versus radius ratio) plane.