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STUDY OF THE EFFECT OF MASS DISTRIBUTION, PATH OF ENERGY AND DYNAMIC COUPLING ON COMBINED COHERENCE (A NON-LINEARITY DETECTION METHOD)

CHENNAGOWNI, SURESH BABU
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1146177646

Abstract Details

2006, MS, University of Cincinnati, Engineering : Mechanical Engineering.
Almost all practical systems are non-linear to some extent with the non-linearity being caused by one or a combination of factors. If the system is non-linear, errors are introduced in the data analysis and are observed during the modal tests of a structure. For example, high forcing levels may cause the frequency response function estimates to show non-coherent behavior over certain frequency bands. A new coherence function (Combined Coherence) provides a method to separate the effects of structural non-linearities and the digital signal processing errors. Thomas Roscher [1] applied the combined coherence formulation to theoretical data generated from a lumped parameter (M, K, C) with static coupling. The results showed improvement in the combined coherence function over the ordinary coherence, but when Doug Coombs [2] applied combined coherence to a real world structure, it did not show improvement. In this thesis, as an extension of previous work, study is done on theoretical data generated from a lumped mass model with dynamic coupling. The effects of mass distribution, spatial density, forcing level, location of forcing function, path of energy and the dynamic coupling on the combined coherence are studied. The testing cases include SIMO and MIMO cases for a MDOF simulink model with a cubic hardening type of nonlinearity applied at different locations. Combined Coherence is calculated for a non-linear model and effects on the combined coherence are studied for the following cases. 1) Effect of varying the force input 2) Effect of dynamic coupling 3) Effect of location of input and path of energy 4) Effect of mass distribution 5) Effect of spatial density of masses and 6) Effect of scaling of motions.
Dr. Randall Allemang (Advisor)
114 p.

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Citations

  • CHENNAGOWNI, S. B. (2006). STUDY OF THE EFFECT OF MASS DISTRIBUTION, PATH OF ENERGY AND DYNAMIC COUPLING ON COMBINED COHERENCE (A NON-LINEARITY DETECTION METHOD) [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1146177646

    APA Style (7th edition)

  • CHENNAGOWNI, SURESH BABU. STUDY OF THE EFFECT OF MASS DISTRIBUTION, PATH OF ENERGY AND DYNAMIC COUPLING ON COMBINED COHERENCE (A NON-LINEARITY DETECTION METHOD). 2006. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1146177646.

    MLA Style (8th edition)

  • CHENNAGOWNI, SURESH BABU. "STUDY OF THE EFFECT OF MASS DISTRIBUTION, PATH OF ENERGY AND DYNAMIC COUPLING ON COMBINED COHERENCE (A NON-LINEARITY DETECTION METHOD)." Master's thesis, University of Cincinnati, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1146177646

    Chicago Manual of Style (17th edition)

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© 2006, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.