Abstract
The ability of smart materials to deliver large block forces in a small package while operating at high frequencies makes them extremely attractive for converting electrical power into mechanical power. This has led to the development of hybrid actuators consisting of co-located smart material actuated pumps and hydraulic cylinders. The overall success of the hybrid concept hinges on the effectiveness of the coupling between the smart material and the fluid. This study presents the results of two and three-dimensional (3D) simulations of fluid flow in a prototype hybrid actuator being developed for aerospace applications. The steady simulations show that losses in the device result primarily from three-dimensional effects like radial acceleration of the fluid in the pumping chamber, and the formation of vortex ring structures that block the flow. The effects of varying design parameters like pumping chamber height, discharge tube location, and discharge tube chamfer are explored and are found to have significant impacts on performance. Analytical expressions for the scaling of pressure losses with driving frequency are presented.