Finite element model updating of aerospace structures

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Date

2017

Author

Ünlü, Doğuş

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Model updating methods can be used to obtain more accurate mathematical models. Results of linear finite element models which can be assumed as mathematical models for structural dynamics studies almost never match with the real test results. Accurate mathematical models are used to extract more precise results from structural analyses. The model update theory is classified with respect to the solution method as direct and iterative methods. As a summary, direct methods use structural matrices while iterative methods use the modal or response function results in an iterative manner. Selection of the model updating method is initiated with the application of the methods to simple spring-mass system. The advantages and disadvantages of the methods are clarified by extracting the results for direct and iterative methods. Modal based iterative methods are selected to be applied effectively to large order finite element models. Algorithm is developed by using Inverse Eigensensitivity method with the enhancement which reduces the total time of the updating procedure. Improved method is applied to case studies to see the effect of enhancement and it is concluded that it can reduce the elapsed time great amount. Additionally, Femtools commercial software is used to analyze a test fixture and to update the finite element model to build insight and know-how about the commercial finite element updating software.

Subject Keywords

Finite element method., Structural dynamics., Functions, Inverse., Eigenvalues.

URI

http://etd.lib.metu.edu.tr/upload/12621914/index.pdf
https://hdl.handle.net/11511/27114

Collections

Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

D. Ünlü, “Finite element model updating of aerospace structures,” M.S. - Master of Science, Middle East Technical University, 2017.