Investigation of asymmetric cubic nonlinearity using broadband excitation
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University of Cincinnati / OhioLINK
2019
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ndltd-OhioLink-oai-etd.ohiolink.edu-ucin15536140757476022021-08-03T07:09:47Z Investigation of asymmetric cubic nonlinearity using broadband excitation Chawla, Rohan D. Mechanical Engineering Structural Vibrations Nonlinear Systems Shakers Excitation Pneumatic Excitation Broadband Excitation Traditionally, electrodynamic shakers have been used to test nonlinear systems using sinusoidalexcitation. However random excitation is desirable due to its lower testing times. Inboth cases, shakers affect system dynamics when used to test relatively light structures byintroducing additional impedance. On the other hand, pneumatic excitation, a new techniquedeveloped at UC-SDRL [1] used for linear system identification, is used here to testnonlinear systems. This thesis focuses on testing a rig with a flexible beam with a knowncubic nonlinearity using both a traditional electrodynamic shaker as well as the pneumaticexcitation method. The results of these two methods are compared with each other.The property of nonlinear systems showing the presence of uncorrelated response at harmonicsof the natural frequency is used in this thesis to investigate asymmetry in the system.Bilinearity present in the system due to asymmetry which was hard to detect from shakertest was clearly evident in pneumatic excitation test. The dips in the coherence functionpresent due to harmonics of nonlinear response is differentiated from leakage errors usinga nonlinearity detection algorithm developed at UC-SDRL. The presence of bilinearity isfurther confirmed by static loading tests in both directions as well as dynamic testing inthe loaded conguration. The conclusions of the comparative study are presented and advantagesof using pneumatic excitation over traditional shaker excitation are stated in the end. 2019-06-25 English text University of Cincinnati / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=ucin1553614075747602 http://rave.ohiolink.edu/etdc/view?acc_num=ucin1553614075747602 unrestricted This thesis or dissertation is protected by copyright: some rights reserved. It is licensed for use under a Creative Commons license. Specific terms and permissions are available from this document's record in the OhioLINK ETD Center. |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Mechanical Engineering Structural Vibrations Nonlinear Systems Shakers Excitation Pneumatic Excitation Broadband Excitation |
| spellingShingle |
Mechanical Engineering Structural Vibrations Nonlinear Systems Shakers Excitation Pneumatic Excitation Broadband Excitation Chawla, Rohan D. Investigation of asymmetric cubic nonlinearity using broadband excitation |
| author |
Chawla, Rohan D. |
| author_facet |
Chawla, Rohan D. |
| author_sort |
Chawla, Rohan D. |
| title |
Investigation of asymmetric cubic nonlinearity using broadband excitation |
| title_short |
Investigation of asymmetric cubic nonlinearity using broadband excitation |
| title_full |
Investigation of asymmetric cubic nonlinearity using broadband excitation |
| title_fullStr |
Investigation of asymmetric cubic nonlinearity using broadband excitation |
| title_full_unstemmed |
Investigation of asymmetric cubic nonlinearity using broadband excitation |
| title_sort |
investigation of asymmetric cubic nonlinearity using broadband excitation |
| publisher |
University of Cincinnati / OhioLINK |
| publishDate |
2019 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1553614075747602 |
| work_keys_str_mv |
AT chawlarohand investigationofasymmetriccubicnonlinearityusingbroadbandexcitation |
| _version_ |
1719455352556093440 |