Design of Piezo-SMA Composite for Thermal Energy Harvester Under Fluctuating Temperature

摘要

A thermal energy harvester using piezo-shape memory alloy (SMA) composite was de-nsigned. The main mechanism of such a piezo-SMA composite is the synergistic effect ofnpiezoelectrics and SMA, which are connected in series and subjected to fluctuating tem-nperature. Strain induced in the SMA phase immediately causes stress in the piezoelectricnphase, thus, inducing charge by the direct piezoelectric effect. In order to make thisnproblem more analytically tractable, two models were developed: simple laminatednmodel and 3D model with Eshelby theory. The models predict the available power ac-ncording to material properties and thermal fluctuation. The impedance of the system wasnexamined with different thermal fluctuating frequencies. Experimental and predicted re-nsults are in agreement for higher frequencies, while for lower frequencies of thermalnfluctuation, the prediction is not accurate due to internal loss. u0001DOI: 10.1115/1.4002592