A nonlinear energy sink with energy harvester

Abstract

The transfer of energy between systems is a natural process, manifesting in many different ways. In engineering transferable energy can be considered wanted or un- wanted. Specifically in mechanical systems, energy transfer can occur as unwanted vibrations, passing from a source to a receiver. In electrical systems, energy trans- fer can be desirable, where energy from a source may be used elsewhere. This work proposes a method to combine the two, converting unwanted mechanical ener- gy into useable electrical energy. A nonlinear energy sink (NES) is a vibration absorber that passively local- izes vibrational energy, removing mechanical energy from a primary system. Con- sisting of a mass-spring-damper such that the stiffness is essentially nonlinear, a NES can localize vibrational energy from a source and dissipate it through damping. Replacing the NES mass with a series of magnets surrounded by coils fixed to the primary mass, the dissipated energy can be directly converted to electrical energy. A NES with energy harvesting properties is constructed and introduced. The system parameters are identified, with the NES having an essentially cubic nonlinear stiffness. A transduction factor is quantified linking the electrical and mechanical systems. An analytic analysis is carried out studying the transient and harmonically excited response of the system. It is found that the energy harvesting does not reduce the vibrational absorption capabilities of the NES. The performance of the system in both transient and harmonically excited responses is found to be heavily influenced by input energies. The system is tested, with good match to analytic results.