On the self-powering of SHM techniques using seismic energy harvesting

Abstract

Growing demands in self-powered, wireless Structural Health Monitoring (SHM) systems has placed a particular attention on energy harvesting products. While most of works done in this domain considered directly coupled active materials, it may be preferential to use seismic (or indirect-coupled) harvesters for maintenance issues. With a seismic type harvester, a model considering constant vibration magnitude excitation is no longer valid as electrical energy extraction from mechanical vibration leads to a reduction of the vibration magnitude of the harvester because of electromechanical coupling effect. This paper extends a Single Degree of Freedom (SDOF) model with a constant force or acceleration excitation to a Two Degree of Freedom (TDOF) approach to describe the tradeoff between the damping effect on the host structure and the harvested power due to the mechanical to mechanical coupling effect. When the harvester mass to host structure mass ratio is around 10^-3, the maximal power is obtained and the host structure has then a sudden displacement reduction due to the strong mechanical to mechanical coupling. Its application to self-powered SHM will be also introduced in the paper.