Using an elastic magnifier to increase power output and performance of heart-beat harvesters

Abstract

Embedded piezoelectric energy harvesting (PEH) systems in medical pacemakers have been a growing and innovative research area. The goal of these systems, at present, is to remove the pacemaker battery, which makes up 60%–80% of the unit, and replace it with a sustainable power source. This requires that energy harvesting systems provide sufficient power, 1–3 μW, for operating a pacemaker. The goal of this work is to develop, test, and simulate cantilevered energy harvesters with a linear elastic magnifier (LEM). This research hopes to provide insight into the interaction between pacemaker energy harvesters and the heart. By introducing the elastic magnifier into linear and nonlinear systems oscillations of the tip are encouraged into high energy orbits and large tip deflections. A continuous nonlinear model is presented for the bistable piezoelectric energy harvesting (BPEH) system and a one-degree-of-freedom linear mass-spring-damper model is presented for the elastic magnifier. The elastic magnifier will not consider the damping negligible, unlike most models. A physical model was created for the bistable structure and formed to an elastic magnifier. A hydrogel was designed for the experimental model for the LEM. Experimental results show that the BPEH coupled with a LEM (BPEH + LEM) produces more power at certain input frequencies and operates a larger bandwidth than a PEH, BPEH, and a standard piezoelectric energy harvester with the elastic magnifier (PEH + LEM). Numerical simulations are consistent with these results. It was observed that the system enters high-energy and high orbit oscillations and that, ultimately, BPEH systems implemented in medical pacemakers can, if designed properly, have enhanced performance if positioned over the heart.

Investigating the influence of the viscoelastic material as a heart muscle simulator on the powering leadless pacemaker from heartbeats by using a piezoelectric beam

“…To solve the governing equations, the relative vibration response of the piezoelectric beam can be represented by an absolutely and uniformly convergent series of the eigenfunctions as 30…”

Identifying the parameters of viscoelastic model for a gel-type material as representative of cardiac muscle in dynamic tests

“…The effect of the dynamic behavior of the myocardium due to heartbeats on the mobility of the leadless pacemaker is of particular importance. 33,34 To obtain complete information about the viscoelastic behavior of the heart muscle, it is necessary to have experimental data over a wide range of time scales. In laboratory research, It is impossible to use a living human cardiac tissue, on the other hand, the dead cardiac muscle does not have the properties of living tissue, and its electromechanical properties change over time.…”