Harmonic vibration analysis of large structures with local nonlinearity

Download
index.pdf
2009
Abat, Diren
Show full item record
192
views
117
downloads
With the rapid development in today’s technology, reliability and performance requirements on components of various mechanical systems, which tend to be much lighter and work under much more severe working conditions, dramatically increased. In general, analysis techniques based on simplified model of structural components with linearity assumption may provide time saving for solutions with reasonable accuracy. However, since most engineering structures are often very complex and intrinsically nonlinear, in some cases they may behave in a different manner which cannot be fully described by linear mathematical models, or linear treatments may not be applicable at all. In fact, some studies revealed that deviations in the modal properties of dynamic structures gathered from measured data are due to nonlinearities in the structure. Hence, in problems where accuracy is the primary concern, taking the nonlinear effects into account becomes inevitable. In this thesis, it is aimed to analyze the harmonic response characteristics of multi degree of freedom nonlinear structures having different type of nonlinearities. The amplitude dependencies of nonlinearities are modelled by using describing function method. To increase the accuracy of the results, effect of the higher order harmonic terms will be considered by using multi harmonic describing function theory. Mathematical formulations are embedded in a computer program developed in MATLAB® with graphical user interface. The program gets the system matricies from the file which is obtained by using substructuring analysis in ANSYS®, and nonlinearities in the system can easily be defined through the graphical user interface of the MATLAB® program.
Mechanical engineering., Structural Nonlinearity.
http://etd.lib.metu.edu.tr/upload/2/12610475/index.pdf
https://hdl.handle.net/11511/18498
Graduate School of Natural and Applied Sciences, Thesis

Suggestions

Assessment of sheet metal forming processes by numerical experiments
Önder, İ. Erkan; Tekkaya, A. Erman; Department of Mechanical Engineering (2005)
Sheet metal forming technologies are challenged especially by the improvements in the automotive industry in the last decades. To fulfill the customer expectations, safety requirements and market competitions, new production technologies have been implemented. This study focuses on the assessment of conventional and new sheet metal forming technologies by performing a systematic analysis. A geometry spectrum consisting of six different circular, elliptic, quad cross-sections are selected for the assessment ...
Vibration fatigue analysis of structures installed on air platforms
Eldoğan, Yusuf; Ciğeroğlu, Ender; Department of Mechanical Engineering (2012)
Although a component satisfies all operating static requirements, failures can still occur due to vibration induced fatigue. Vibration induced fatigue is a frequent phenomenon, in cases where the natural frequencies of the structures are excited by the loading. Hence, the methods which consider all dynamic characteristic of the structure should be used to obtain accurate fatigue life predictions. These methods in frequency domain are called vibration fatigue methods which give accurate, reliable and fast re...
Simulation of flexible manufacturing systems: a pilot implementation
Yücel, Necati Deniz; Kılıç, Sadık Engin; Department of Mechanical Engineering (2005)
Manufacturing industry has made extensive use of simulation as a means of trying to model the impact of variability on manufacturing system behavior and to explore various ways of coping with change and uncertainty. Simulation helps find optimal solutions to a number of problems at both design and application stages of Flexible Manufacturing Systems (FMS̕s) serving to improve the أflexibilityؤ level The flexibility requirement of FMS necessitates the dissemination of every activity that concerns production,...
Optimum Profile Modifications for the Minimization of Dynamic Transmission Error
ÖZTÜRK, VEYSEL YALIN; Ciğeroğlu, Ender; Özgüven, Hasan Nevzat (2014-08-28)
An optimization study is performed target being the reduction of dynamic transmission error (DTE) for a selected operational range, where the operating torque and speed ranges are defined. For this purpose, two different models, i.e. a single degree of freedom (SDOF) lumped gear dynamics model and a multi-degree of freedom (MDOF) lumped model of a gear pair which is combined with shaft and bearing dynamics are employed. The differences between the optimization results obtained through loaded static transmis...
Conceptual design and analysis of an industrial type vacuum sweeper
Aygün, Buket; Albayrak, Kahraman; Department of Mechanical Engineering (2009)
In this thesis, design and development and manufacturing processes of an industrial type vacuum sweeper is presented. Thesis is financially supported by Ministry of Industry and Trade-Turkey and Müsan A.Ş. (Makina Üretim Sanayi ve Ticaret A.Ş.) under SAN-TEZ project number 00028.STZ.2007-1. It is aimed to make innovative design changes and developments on the Müsan VSM 060 type vacuum sweeper. To achieve this aim, alternative configuration designs are prepared by using commercial 3D modeling program, Catia™...
Citation Formats
D. Abat, “Harmonic vibration analysis of large structures with local nonlinearity,” M.S. - Master of Science, Middle East Technical University, 2009.
METU IIS - Integrated Information Service open@metu.edu.tr