Design and characterization of acoustic pulse shape memory alloy actuators
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2006
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| Online Access: | http://hdl.handle.net/1721.1/32378 |
| _version_ | 1826193066468311040 |
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| author | Chambers, Joshua Michael |
| author2 | Steven R. Hall. |
| author_facet | Steven R. Hall. Chambers, Joshua Michael |
| author_sort | Chambers, Joshua Michael |
| collection | MIT |
| description | Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005. |
| first_indexed | 2024-09-23T09:33:14Z |
| format | Thesis |
| id | mit-1721.1/32378 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T09:33:14Z |
| publishDate | 2006 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/323782019-04-11T14:28:06Z Design and characterization of acoustic pulse shape memory alloy actuators Chambers, Joshua Michael Steven R. Hall. Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Mechanical Engineering. Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005. Includes bibliographical references (p. 175-177). Single crystal Ni-Mn-Ga ferromagnetic shape memory alloys (FSMAs) are active materials which produce strain when a magnetic field is applied. The large saturation strain (6%) of Ni-Mn-Ga, and material energy density comparable to piezoelectric ceramics make Ni- Mn-Ga an interesting active material. However, their usefulness is limited by the bulky electromagnet required to produce a magnetic field. In this thesis, a novel actuation method is developed for shape memory alloys in their martensitic phase, whereby asymmetric acoustic pulses are used to drive twin boundary motion. Experimental actuators were developed using a combination of Ni-Mn-Ga FSMA single crystals and a piezoelectric stack actuator. In bi-directional actuation without load, strains of over 3% were achieved using repeated pulses (at 100 Hz) over a 30 s interval, while 1% strain was achieved in under 1 s. The maximum strains achieved are comparable to the strains achieved using bi-directional magnetic actuation, although the time required for actuation is longer. No-load actuation also showed a nearly linear relationship between the magnitude of the asymmetric stress pulse and the strain achieved during actuation, and a positive correlation between pulse repetition rate and output strain rate, up to at least 100 Hz. Acoustic actuation against a spring load showed a maximum output energy density for the actuator of about 1000 J/m³, with a peak-to-peak stress and strain of 100 kPa and 2%, respectively. by Joshua Michael Chambers. S.M. 2006-03-29T18:39:04Z 2006-03-29T18:39:04Z 2005 2005 Thesis http://hdl.handle.net/1721.1/32378 61522803 eng 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 177 p. 8909302 bytes 8919756 bytes application/pdf application/pdf application/pdf Massachusetts Institute of Technology |
| spellingShingle | Mechanical Engineering. Chambers, Joshua Michael Design and characterization of acoustic pulse shape memory alloy actuators |
| title | Design and characterization of acoustic pulse shape memory alloy actuators |
| title_full | Design and characterization of acoustic pulse shape memory alloy actuators |
| title_fullStr | Design and characterization of acoustic pulse shape memory alloy actuators |
| title_full_unstemmed | Design and characterization of acoustic pulse shape memory alloy actuators |
| title_short | Design and characterization of acoustic pulse shape memory alloy actuators |
| title_sort | design and characterization of acoustic pulse shape memory alloy actuators |
| topic | Mechanical Engineering. |
| url | http://hdl.handle.net/1721.1/32378 |
| work_keys_str_mv | AT chambersjoshuamichael designandcharacterizationofacousticpulseshapememoryalloyactuators |