Department of Mechanical Engineering, University of Tabriz, Tabriz, Iran.
Department of Mechanical Engineering, Sahand University of Technology, Tabriz, Iran.
Proc Inst Mech Eng H. 2022 Sep;236(9):1414-1429. doi: 10.1177/09544119221111213. Epub 2022 Jul 21.
This paper studies experimentally and analytically the influence of the viscoelastic cardiac muscle on the energy harvesting from heartbeats for powering the leadless pacemakers by using a piezoelectric beam. An appropriate representative gel-type viscoelastic material that mimics the heart tissue is used in the tests. The piezoelectric beam coupled with a gel-type material is analytically modeled, and experimentally tested. By considering a combination of the translational standard linear solid model and a rotational spring component for the gel-type material, the analytical model of the coupled system is developed utilizing the generalized Hamilton's principle. The system is attached on top of a shaker and excited harmonically, and the time history of output voltage and accelerations are measured. The analytical model is verified by experimental results for the tip displacement, voltage, generated power, phase-portraits histories, and voltage FRF with harmonic base excitations. Transmissibility analysis by the analytical model shows that for excitation frequencies beyond a specific frequency, the viscoelastic material can magnify the amplitude of the excitation and incredibly improve the power generation. Experimental results demonstrate that by coupling the gel into the harvester, oscillations of the tip are increased into high energy orbits and large tip deflections around the resonance frequency. The significantly widened frequency bandwidth and the increased power output at specific input frequencies are the other results of considering the viscoelastic characteristics of the heart wall in the dynamic investigations. By simulating the response of the energy harvesting system to the heartbeat impulsive rhythm, when the energy harvesting system is attached to the viscoelastic material, the output power is increased from 18 to 55 µW. The obtained results reveal that influence of the viscoelastic properties of the heart muscle is crucial in the accurate design of the energy harvesting system for the self-powered medical leadless pacemaker.
本文通过使用压电梁实验和分析研究了粘弹性心肌对从心跳中获取能量以为无引线起搏器供电的影响。在测试中使用了一种适当的代表性凝胶型粘弹性材料，该材料模拟心脏组织。对与凝胶型材料耦合的压电梁进行了分析建模和实验测试。通过考虑组合平移标准线性固体模型和用于凝胶型材料的旋转弹簧组件，利用广义哈密顿原理开发了耦合系统的分析模型。将系统安装在振动台上并进行谐波激励，并测量输出电压和加速度的时间历史。通过实验结果验证了分析模型的模型，实验结果包括尖端位移、电压、产生的功率、相图历史以及具有谐波基础激励的电压 FRF。分析模型的传递分析表明，对于激励频率超过特定频率的情况，粘弹性材料可以放大激励的幅度，并令人难以置信地提高发电效率。实验结果表明，通过将凝胶耦合到发电机中，尖端的振动可以增加到高能轨道，并在共振频率周围产生较大的尖端偏移。在特定输入频率下，显著拓宽的频率带宽和增加的功率输出是在动态研究中考虑心壁粘弹性特性的其他结果。通过模拟能量收集系统对心跳脉冲节律的响应，当能量收集系统附接到粘弹性材料时，输出功率从 18µW 增加到 55µW。所得结果表明，心肌的粘弹性特性对自供电医疗无引线起搏器的能量收集系统的精确设计具有重要影响。
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