Non-Iterative Mode Shape Expansion for Beam Structures Based on Coordinate Decomposition

Abstract:

The direct mode shape expansion method is an iterative technique, then one can conclude that the convergence performance maybe challenged when applied to three-dimensional structures. In addition, mode shape values at different DOFs (degrees-of-freedom) sometimes are not in a same order of magnitude, which will produce much error for the estimation of small values of unmeasured mode components. Thus, this paper proposed a non-iterative mode shape expansion method based on coordinate decomposition and neglecting modelling errors between the finite element model and the experimental structure. The advantage of coordinate decomposition is that the unmeasured components of mode shape values could be estimated with different weighting coefficients, even in a physical meaningful interval. Numerical studies in this paper are conducted for a 30-DOF (degree-of-freedom) cantilever beam with multiple damaged elements, as the measured modes are synthesized from finite element models. The results show that the approach can estimate unmeasured mode shape values at translational and rotational DOFs in x, y and z directions with different weighting coefficients, respectively; and better mode shape expansion results can be obtained when proper constraints are employed.

• Periodical: Applied Mechanics and Materials (Volumes 284-287)
• Pages: 503-507
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.284-287.503
• Online since: January 2013
• Authors: Fu Shun Liu, Wen Wen Chen, Chun Fu Peng, Wei Li
• Keywords: Beam Structure, Coordinate Decomposition, Direct Mode Shape Expansion, Non-Iterative

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