In some embodiments, the present invention is directed to an actuator which includes at least the following: a pre-stretched electro-active polymer film being pre-stretched in a single or biaxial planar directions; at least one first semi-stiff conductor attached to a first surface of the pre-stretched electro-active polymer film, wherein the first surface is parallel to the single or biaxial planar stretch directions; at least one second semi-stiff conductor attached to a second surface of the pre-stretched electro-active polymer film, wherein the second surface is opposite to the first surface; where the semi-stiff conductors are configured to: fix the pre-stretched electro-active polymer film in a pre-stretched state and allow the pre-stretched electro-active polymer film to expand; a pair of mechanical connectors coupled to each end of an active region of the pre-stretched electro-active polymer film.

A method is provided for manufacturing a dielectric elastomer transducer including a dielectric elastomer layer and electrode layers sandwiching the elastomer layer. The elastomer layer when stretched exhibits a stress-strain curve having: a low strain and high elasticity region; a low elasticity region; and a high strain region. The method includes: a pre-stretching process to reduce hysteresis in elastic behavior of the elastomer layer by stretching the elastomer layer one or more times under a load as heavy as a first load before the electrodes are provided, each stretching causing the elastomer layer to undergo a tension falling in the low elasticity region; and a dielectric elastomer layer fixing process including applying a second load smaller than the first load to the elastomer layer so as to fix the elastomer layer to a support member under a second tension smaller than the first tension.

An energy harvesting system can be used to exploit freely available flow energy with a piezoelectric device(s). The system may include a piezoelectric device and a flow disruptor, such as a blunt body that creates flow turbulence and flow characteristic randomization that can increase movement response from the piezoelectric device and enhance electrical power generation. Multiple piezoelectric devices may be linked to each other to enhance movement of a less-influenced piezoelectric device from translated movement of a more-influenced piezoelectric device and create more electrical power than a single piezoelectric device subjected to the same flowing fluid.

A piezoelectric drive device includes a vibrating part which has a piezoelectric element, and drives a driven part using the piezoelectric element, and a first plate spring part configured to bias the vibrating part in a first direction from the vibrating part toward the driven part. The first plate spring part extends toward a second direction crossing the first direction, the first plate spring part is disposed so as to be opposed to the vibrating part in a third direction perpendicular to the first direction and the second direction, and when dividing the first plate spring part into a first portion and a second portion farther from the vibrating part than the first portion so that a length along the third direction is equally divided, a volume of the second portion is larger than a volume of the first portion.

A Piezo-electric transceiver for a vibration sensor, with the Piezo-electric transceiver being embodied as a separately handled unit with a drive seat comprising a mechanical connection section for connecting the Piezo-electric transceiver to a mechanical oscillation unit of the vibration sensor.

A downhole acoustic transmitter has a piezoelectric transducer, an enclosure in which the piezoelectric transducer is housed, a transducer preload means which applies a selected compressive force against the transducer such that a mechanical preload is applied to the transducer, and an acoustic tuning element which has a first end coupled to the transducer preload means or the transducer, and an open second end. The acoustic tuning element is not coupled to anything but the transducer preload means or transducer, so the transducer preload means effectively has a second open end and thus can maintain the same preload compressive force on the transducer even when the transmitter is subjected to tension and compressive forces during operation.

A piezoelectric actuator includes: a piezoelectric element; and a case including a base body and a tubular body, the case being configured to receive the piezoelectric element. The base body includes a bottom plate portion and an annular projection disposed upright on the bottom plate portion. The annular projection includes an upper-side first region having a relatively small outside diameter and a lower-side second region having a relatively large outside diameter, and includes a stepped outer surface defined by an outer surface of the first region and an outer surface of the second region that are connected with each other. The first region is inserted inside the tubular body, an end face of the tubular body abuts on an upper end of the second region, and the tubular body and the second region is joined to each other.

A structure including an electro-active-polymer (“EAP”). The structure can take the form of a strap, which includes two or more EAP film layers. The structure can further include one or more holders or end-grabbing portions. Methods of making and using the EAP structure are also envisioned.

An energy harvesting system can be used to exploit freely available flow energy with a piezoelectric device(s). The system may include a piezoelectric device and a flow disruptor, such as a blunt body that creates flow turbulence and flow characteristic randomization that can increase movement response from the piezoelectric device and enhance electrical power generation. Multiple piezoelectric devices may be linked to each other to enhance movement of a less-influenced piezoelectric device from translated movement of a more-influenced piezoelectric device and create more electrical power than a single piezoelectric device subjected to the same flowing fluid.

A piezoelectric vibration energy harvester includes: a first support plate, a second support plate, a piezoelectric bimorph cantilever, a rolling part, a printing raceway, a preloading spring and a bottom plate, the first and second support plates are vertically disposed on the bottom plate, two ends of the piezoelectric bimorph cantilever are respectively connected with the first support plate and the rolling part, an end of the preloading spring is fixed on the second support plate, another end of the preloading spring is movably connected with a back surface of the printing raceway, and a surface opposite to the back surface of the printing raceway is in contact with and coupled with the rolling part. The printing raceway can be obtained by programming the number and initial positions of static equilibrium points, and a multi-stable piezoelectric energy harvester with symmetric or asymmetric potential energy well can be realized.