2026-09-19T00:25:14Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/879582022-01-13T07:54:05Zcom_1721.1_7582com_1721.1_7581col_1721.1_131023
Alexander H. Slocum and Themistoklis P. Sapsis.
Kluger, Jocelyn Maxine
Massachusetts Institute of Technology. Department of Mechanical Engineering.
Massachusetts Institute of Technology. Department of Mechanical Engineering
2014-06-13T22:36:33Z
2014-06-13T22:36:33Z
2014
2014
http://hdl.handle.net/1721.1/87958
880676309
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 216-218).
This thesis studies a novel nonlinear spring mechanism that is comprised of a cantilever wrapping around a curved surface as it deflects. Static force versus displacement tests and dynamic "initial displacement" tests verified the spring theory for a large range of oscillator parameters. Various human motion energy harvester configurations that use the nonlinear spring were numerically optimized for power, robustness, and adaptivity. Based on the optimization results, both the nonlinear and linear devices studied in this thesis generate more power per volume and per mass when excited at one's hip while walking than current commercial energy harvesters. The two degree-of-freedom (2DOF) nonlinear oscillator is more adaptive to different excitation signals and resistant to power decay when parasitic damping is present than the IDOF and 2DOF linear systems. These significant advantages are caused by the 2DOF nonlinear system harvesting its optimal power at large electromagnetic damping coefficients, whereas the optimal power generation for the linear systems occurs at low electromagnetic damping coefficients. This thesis also examined what electromagnetic damping coefficients can be generated by magnet-and-coil geometries that satisfy the energy harvester constraints. The final chapter of this thesis investigates a load cell that uses the stiffening spring to maintain high resolution over a large range of forces and prevent large forces from damaging the load cell. Future work will include testing a full energy harvester prototype and exploring other applications of the nonlinear spring.
by Jocelyn Maxine Kluger.
S.M.
218 pages
eng
Massachusetts Institute of Technology
M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.
http://dspace.mit.edu/handle/1721.1/7582
Mechanical Engineering.
Nonlinear beam-based vibration energy harvesters and load cells
Thesis
application/pdf
Publication
unknown
unknown
<Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="66f1395f-ee26-447c-a06a-caaa6ae19017">
<Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type>
<Language>eng</Language>
<Title>Nonlinear beam-based vibration energy harvesters and load cells</Title>
<PublishedIn>
<Publication>
</Publication>
</PublishedIn>
<PublicationDate>2014</PublicationDate>
<Authors>
<Author>
<DisplayName>Kluger, Jocelyn Maxine</DisplayName>
<Affiliation>
<OrgUnit>
</OrgUnit>
</Affiliation>
</Author>
</Authors>
<Editors>
</Editors>
<Publishers>
<Publisher>
<DisplayName>Massachusetts Institute of Technology</DisplayName>
<OrgUnit />
</Publisher>
</Publishers>
<License>http://dspace.mit.edu/handle/1721.1/7582</License>
<Keyword>Mechanical Engineering.</Keyword>
<Abstract>This thesis studies a novel nonlinear spring mechanism that is comprised of a cantilever wrapping around a curved surface as it deflects. Static force versus displacement tests and dynamic "initial displacement" tests verified the spring theory for a large range of oscillator parameters. Various human motion energy harvester configurations that use the nonlinear spring were numerically optimized for power, robustness, and adaptivity. Based on the optimization results, both the nonlinear and linear devices studied in this thesis generate more power per volume and per mass when excited at one's hip while walking than current commercial energy harvesters. The two degree-of-freedom (2DOF) nonlinear oscillator is more adaptive to different excitation signals and resistant to power decay when parasitic damping is present than the IDOF and 2DOF linear systems. These significant advantages are caused by the 2DOF nonlinear system harvesting its optimal power at large electromagnetic damping coefficients, whereas the optimal power generation for the linear systems occurs at low electromagnetic damping coefficients. This thesis also examined what electromagnetic damping coefficients can be generated by magnet-and-coil geometries that satisfy the energy harvester constraints. The final chapter of this thesis investigates a load cell that uses the stiffening spring to maintain high resolution over a large range of forces and prevent large forces from damaging the load cell. Future work will include testing a full energy harvester prototype and exploring other applications of the nonlinear spring.</Abstract>
<Access xmlns="http://purl.org/coar/access_right"
>
</Access>
</Publication>