The shear-mode of a piezoceramic material offers improved energy harvesting potential as compared to other modes. This paper presents a concept of using torsional stresses induced by nonrotational vibrations in an energy harvesting device to produce electrical power. A finite-element model of this concept is presented to illustrate the principle and a prototype is demonstrated to validate the design. This prototype harvester is found to be capable of producing a maximum power of 0.57 mW at its resonant frequency of 620 Hz with a base acceleration of 1 g in amplitude. When compared to conventional cantilever harvester designs, this torsion-based harvester is found to suffer from fewer electrical power losses and has a greater potential in producing high power outputs.

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Energy harvesting devices are growing in popularity for their ability to capture the ambient energy surrounding a system and convert it into usable electrical energy. With an increasing demand for portable electronics and wireless sensors in a number of sectors, energy harvesting has the potential to create self-powered sensor systems operating in inaccessible locations. This paper discusses a torsion based piezoelectric energy harvester that utilizes superior shear mode piezoelectric properties to harvest energy from vibrations. Mathematical expressions are used to determine optimized geometry configurations for the harvester. Using these expressions, a harvester design is presented for use with wireless sensor networks.

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Piezoceramics energy harvesters can transform ambient vibration energy into electrical signals and thus they are being explored for their potential to create self-powered devices for a variety of applications. However, currently available harvesters suffer from low-power outputs. This paper presents a concept of a shear mode piezoceramic energy harvester that utilizes favourable material properties to improve output power harvested from ambient mechanical vibrations. A model of this harvester is also presented to predict the power output and other characteristics of the harvester under various environments.