A ground-breaking paper reporting the experimental observation of up to 28 orders of parametric resonance, which has, until now, only been predicted in the theoretical realm, has been published in Scientific Reports.
Titled Twenty-Eight Orders of Parametric Resonance in a Microelectromechanical Device for Multi-band Vibration Energy Harvesting, and co-authored by CSIC Co-Investigator, Dr Ashwin Seshia, CSIC PhD student Sijun Du and former CSIC Research Associate and currently Lecturer at the University of Chester, Dr Yu Jia, the article is available freely online here.Scientific Reports is an online, fully open-access journal from the publishers of Nature and publish scientifically-valid primary research from all areas of the natural and clinical sciences.
While theory has long predicted conditions for the onset of n orders of parametric resonance in mechanical systems, previously reported experimental observations have been limited up to about the first 5 orders. This is due to the rapid narrowing nature of the frequency bandwidth of the higher instability intervals, making practical accessibility increasingly more difficult. In this paper the authors have experimentally confirmed up to 28 orders of parametric resonance in a micromachined membrane resonator when electrically undamped.
The micro-electro-mechanical system (MEMS) circular disk membrane resonator – a circular membrane supported by a single-crystal silicon substrate with a centered silicon proof mass, was designed by the researchers and fabricated using standard semiconductor batch manufacturing techniques, similar to those employed for manufacturing microprocessor chips.
Besides demonstrating experimental validation of the theory underlying the phenomenon of parametric resonance, the results presented in this research article lays the foundation for MEMS devices as an experimental test-bed to investigate and validate the current theory for higher order instabilities and enable physical insight into the nonlinear effects operative in such systems.
While the published results have broad applicability across the vibration dynamics and transducers application spectrum, the immediate significance of this work is towards broadening the accumulative operational frequency bandwidth of vibration energy harvesters for enabling self-powered microsystems. This work represents an important step towards constructing more efficient MEMS-scale energy harvesters that could deliver significant gains in the efficiency of vibration energy generation.
The development of MEMS-scale energy harvesters has potential future implications for infrastructure sensing, including miniaturised chip-scale battery-free sensors or wireless modules that could be fabricated in very large volumes at low cost using semiconductor batch processing techniques. However, additional ancillary technologies will need to be developed to enable such systems, including low-power sensors, chip-scale energy storage and low-power wireless technologies.
The technology is licensed to a CSIC spin-off, 8power, that has received initial funding of approximately £700,000 from IP Group plc (LSE: IPO), the University of Cambridge and the University of Cambridge Enterprise Fund III, managed by Parkwalk Advisors. The company has been founded to develop and commercialise novel technology for sensing and measurement in industrial applications.
The University of Cambridge is a world leader in the science and technology of sensing, and is pioneering the research of new sensor technologies applied to condition monitoring of built infrastructure and machinery through the Cambridge Centre for Smart Infrastructure and Construction and a number of other research groups.