Submerged Stadium-Shaped Pressure Differential Dielectric Elastomer Generator for Wave Energy Conversion

Ocean wave energy is a promising renewable resource, but its exploitation is limited by the cost and complexity of conversion systems. Dielectric Elastomer Generators (DEGs) are emerging as lightweight, corrosion-resistant, and scalable alternatives. This paper introduces a Pressure Differential Wave Energy Converter based on a stadium-shaped submerged DEG (SS-PD-DEG). A finite element model was developed to describe the system electro elastic response, capturing the non-axisymmetric deformation of the membrane under uniform and hydrostatic loading and to predict capacitance variations. A small-scale prototype was designed, manufactured, and tested both in air and underwater. Results confirmed the capability of the SS-PD-DEG to perform full energy generation cycles while operating in underwater conditions. Besides the demonstration of operation, in-air and submerged tests have confirmed the quality of the modelling approach and theoretical predictions. Underwater tests also demonstrated a hydrostatic-induced negative stiffness effect, enabling extended deformability and potential for broadband frequency response.