Alcala, Lucia R.

Durhuus, Døgg

Larsen, Mikkel V.

Lei, Anders

Thomsen, Erik Vilain

Online Research Database In Technology

                       General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.  • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal   If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.     Downloaded from orbit.dtu.dk on: Nov 08, 2017FEM Validation of a Single Degree of Freedom Model for Piezoelectric EnergyHarvestersAlcala, Lucia R.; Lei, Anders; Larsen, Mikkel V.; Durhuus, Døgg; Thomsen, Erik VilainPublication date:2015Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Alcala, L. R., Lei, A., Larsen, M. V., Durhuus, D., & Thomsen, E. V. (2015). FEM Validation of a Single Degree ofFreedom Model for Piezoelectric Energy Harvesters. Poster session presented at DTU Sustain Conference2015, Lyngby, Denmark.FEM Validation of a Single Degree of Freedom Model for Piezoelectric Energy Harvesters Ambient vibrations are present in different environments. Energy can be extracted from these sources by using piezoelectric energy harvesters, enabling these devices to obtain low-power energy.  Lucia R. Alcala, Anders Lei, Mikkel V. Larsen, Døgg Durhuus, Erik V. Thomsen. Most ambient vibrations extend over a wide low frequency range. Therefore, the design of the cantilevers must be aimed at very low frequencies. This can be achieved by tuning the cantilever thickness and relative dimensions of the proof mass and cantilever beam.  Analytical models were validated by FEM simulation methods, which allow for an optimal design.  The devices are aimed  to replace low-power batteries, for that reason the total lengths of the devices should be preferable within one centimetre.          Figure 1. Schematic design of the cantilever used in the analytical and FEM calculations.   DTU Nanotech Device’s optimal  dimensions   The optimal relative dimensions of the proof mass and the cantilever as well as the thickness of the cantilevers are studied in order to achieve the lowest resonance frequency.           Figure 2. Resonant frequency as a function of ratio between proof mass length and beam length for both the FEM and analytical models.           Figure 3. Resonant frequency as a function of cantilever thickness for both FEM and analytical models.         Piezoelectric material  The piezoelectric material Aluminium Nitride (AlN) is normally deposited via reactive sputtering, which is a time-consuming process. It becomes therefore important to determine how the thickness of the AlN layer affects the output power that can be harvested.   Fig. 4 shows the power versus the piezoelectric layer thickness, it can be seen that the power depends on the thickness until a certain value is reached. Beyond that value the AlN thickness does not affect the obtained power, being it constant over thicker layers.              Figure 4. Maximum power obtained ffrom the device as a function of the AlN thickness for both the FEM and analytical models.   Lm/(L+Lm)0 0.2 0.4 0.6 0.8 1Resonant frequency [Hz]250300350400450500AnalyticalFEMSi cantilever thickness [µm]0 10 20 30 40 50Resonant frequency [Hz]0200400600AnalyticalFEMAlN thickness [nm]0 200 400 600 800 1000Peak RMS Power [µW]010203040AnalyticalFEM

FEM Validation of a Single Degree of Freedom Model for Piezoelectric Energy Harvesters

http://orbit.dtu.dk/ws/files/119499192/Sustain2015_lucia_poster_4.pdf

FEM Validation of a Single Degree of Freedom Model for Piezoelectric Energy Harvesters

Abstract

Similar works

Full text

Available Versions

Online Research Database In Technology