Topology Optimisation for High Frequency Vibration Energy Harvesting

Topology optimisation has been used to design a piezoelectric energy harvester capable of harvesting the vibration present on a helicopter gearbox. The gearbox vibrations, with frequencies in the kilo-hertz range and having amplitudes of 10-100g (where g = 9.81 m/s2), are generated by gear-meshing within the transmission. These accelerations, large in amplitude and high in frequency, are ideal sources for vibration energy harvesting, with the harvested power potentially used to power autonomous condition-based-maintenance systems. This paper will discuss the first and simplest of the harvesters that were designed and manufactured, i.e. a 0.51 mm thick spring steel cantilever that uses a Pz27 piezoceramic transducer, which is sensitive to 1900 Hz gearbox vibrations and can produce 300 µW from a 2g host acceleration.