Efficient Solution of the Fuzzy Eigenvalue Problem in Structural Dynamics

Y Xia & MI Friswell (Swansea University)

Engineering Computations, Vol. 31, No. 5, 2014, pp. 864-878

Abstract

Purpose: Many analysis and design problems in engineering and science involve uncertainty to varying degrees. This paper is concerned with the structural vibration problem involving uncertain material or geometric parameters, specified as fuzzy parameters. The requirement is to propagate the parameter uncertainty to the eigenvalues of the structure, specified as fuzzy eigenvalues. However, the usual approach is to transform the fuzzy problem into several interval eigenvalue problems by using the α-cuts method. Solving the interval problem as a generalized interval eigenvalue problem in interval mathematics will produce conservative bounds on the eigenvalues. This paper investigates strategies to efficiently solve the fuzzy eigenvalue problem.

Design/methodology/approach: Based on the fundamental perturbation principle and vertex theory, an efficient perturbation method is proposed, that gives the exact extrema of the first-order deviation of the structural eigenvalue. The fuzzy eigenvalue approach has also been improved by reusing the interval analysis results from previous α-cuts.

Findings: The proposed method was demonstrated on a simple cantilever beam with a pinned support, and produced very accurate fuzzy eigenvalues. The approach was also demonstrated on the model of a highway bridge with a large number of degrees of freedom.

Originality/value: This proposed Vertex-Perturbation method is more efficient than the standard perturbation method, and more general than interval arithmetic methods requiring the non-negative decomposition of the mass and stiffness matrices. The new increment method produces highly accurate solutions, even when the membership function for the fuzzy eigenvalues is complex.

Paper Availability

This material has been published in Engineering Computations, Vol. 31, No. 5, 2014, pp. 864-878, the only definitive repository of the content that has been certified and accepted after peer review. Copyright and all rights therein are retained by Emerald.


Link to paper using doi: 10.1108/EC-02-2013-0052

Engineering Computations