Feasibility assessment and design of micro hydraulic solid-state transducers

Abstract

The performance of a number of mechanical applications could be greatly improved by the introduction of transducers that are capable of exploiting the inherent power densities of piezoelectric materials. The ability of these solid-state materials to exert large forces at high frequencies engenders them with specific power levels (mass normalized) that are often several orders of magnitude greater than conventional transducers, but their utility is offset by their small achievable strains. A novel concept for a device capable of improved solid-state transduction, Micro Hydraulic Solid-State Transducers (MHSTs), is introduced and explored in this thesis. The concept is comprised of two core principles: ( 1) utilization of a hydraulic system consisting of a pump, valves, and a working fluid to rectify the high frequency reciprocations of a piezoelectric drive element into unidirectional motion, and (2) performance enhancement through miniaturization. The goal is a transducer possessing high power densities that is useful in conventional applications. Feasibility of the MHST concept is evaluated by designing, modeling, and simulating a prototype mechanism. The effects of miniattariza~ion on device performance are investigated and an optimal scale is determined. Concept feasibility is based on predicted system performance, existing issues, and manufacturing constraints. It is concluded that the concept is feasible and warrants further development.