Possibilities for the " parasitic " collection of power from human walking motion are explored. The focus is on the walking action as a source of power because of the extensive range of motion and large dynamic forces associated with the heel strike and the bending of the sole. Two piezoelectric systems: a multilayer laminate made from PVDF foil and a unimorph piezoceramic composite (PZT); as w...

In this paper we develop a mathematical model to simulate the actuation of a multilayer metallic strip. In the first step of the model development, we employ the theory of Judy [4] and Timoshenko [5] to quantify the radius of curvature in the unimorph due to differing thermal coefficients in the constituent materials. The resulting radius of curvature is subsequently used to compute the voltage...

Abstract. This paper is a comparative study of the design spaces of two bio-implantable acoustically excited generator architectures: the thickness-stretch-mode circular piezoelectric plate and the bending-mode unimorph piezoelectric diaphragm. The generators are part of an acoustic power transfer system for implanted sensors and medical devices such as glucose monitors, metabolic monitors, dru...

In this paper we investigate the capability of harvesting the electric energy from mechanical vibrations in a dynamic environment through a unimorph piezoelectric membrane transducer. Due to the impedance matrices connecting the efforts and flows of the membrane, we have established the dynamic electric equivalent circuit of the transducer. In a first study and in order to validate theoretical ...

An inchworm locomotion device is presented that can walk on smooth terrain. It consists of a piezoelectric unimorph and two custom-designed legs. A mathematical model is formulated by superimposing the compliant and rigid-body components of the motion. The model is subsequently utilized to evaluate the ground reaction forces and horizontal velocity. Numerical simulation is performed to select t...

In this investigation we develop a mathematical model to simulate the actuation of a multilayer metallic strip. In the first step of the model development, we employ the theory of Judy [4] and Timoshenko [5] to quantify the radius of curvature in the unimorph due to differing thermal coefficients in the constituent materials. The resulting radius of curvature is subsequently used to compute the...

We have examined a piezoelectric unimorph cantilever (PUC) with unequal piezoelectric and nonpiezoelectric lengths for vibration energy harvesting theoretically by extending the analysis of a PUC with equal piezoelectric and nonpiezoelectric lengths. The theoretical approach was validated by experiments. A case study showed that for a fixed vibration frequency, the maximum open-circuit induced ...

We report the fabrication and frequency characterization of mechanical resonators piezoelectrically actuated with aluminum nitride films. The resonators consist of a freestanding unimorph structure made up of a metal/AlN/metal piezoelectric stack and a Si3N4 supporting layer. We show that the electrical impedance of the one-port device can be used to assess the vibrational behavior of the reson...

Mathematical models and circuitry necessary for optimal energy conversion have been developed for piezoelectric devices because of their ability to convert mechanical energy to electrical energy. The piezoelectric device that is the focus of this study is a curved, thin unimorph prestressed bender. This device consists of layers of piezoelectric material, polyimide, and metal bonded at high tem...