Determination of Dynamically Equivalent FE Models of Structures from Experimental Data

Date

2011

Author

Özgüven, Hasan Nevzat
Karaağaçlı, Taylan
Yıldız, Erdinç N.

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In various applications it is important to determine dynamically equivalent spatial finite element (FE) model of complex structures. For instance, obtaining the FE model of an existing aerospace structure is a major requirement for reliable aeroelastic analysis. In such applications a reliable FE model may not be always available, and when this is so a dynamically equivalent FE model derived from modal test will be very useful. This paper presents a noble method to determine spatial FE model of a structure by using experimentally measured modal data along with the connectivity information of measurement points. The method is based on the mass and stiffness orthogonality equations written using experimentally determined mode shapes and natural frequencies. These equations are solved for geometric and material properties constituting global spatial mass and stiffness matrices of an initial FE model. Starting from this initial FE model, mass and stiffness orthogonality equations are updated iteratively employing experimentally obtained natural frequencies and corresponding eigenvectors from the FE model. Iterations are continued until eigensolution of the updated FE model closely correlates with experimentally measured modal data. A simulated case study on GARTEUR scaled aircraft model is presented in order to demonstrate the applicability of the method.

Subject Keywords

Stiffness Matrix, Beam Element, Modal Data, Stiffness Matrice, Singular Value Decomposition

URI

https://hdl.handle.net/11511/105200

Collections

Department of Mechanical Engineering, Conference / Seminar