A spectral approach for fuzzy uncertainty propagation in finite element analysis

Adhikari, S. and Haddad Khodaparast, H. (2014) A spectral approach for fuzzy uncertainty propagation in finite element analysis. Fuzzy Sets and Systems, 243, pp. 1-24. (doi: 10.1016/j.fss.2013.10.005)

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Abstract

Uncertainty propagation in complex engineering systems with fuzzy variables constitutes a significant challenge. This paper proposes a Polynomial Chaos type spectral approach based on orthogonal function expansion. A fuzzy variable is represented as a set of interval variables via the membership function. The interval variables are further transformed into the standard interval [-1, 1]. Smooth nonlinear functions of standard interval variables are projected in the basis of Legendre polynomials by exploiting its orthogonal properties over the interval [-1, 1]. The coefficients associated with the basis functions are obtained by a Galerkin type of error minimisation. The method is first illustrated using scalar functions of multiple fuzzy variables. Later the method is proposed for elliptic type finite element problems where the technique is extended to vector valued functions with multiple fuzzy variables. The response of such systems can be expressed in the complete basis of multivariate Legendre polynomials. The coefficients, obtained by Galerkin type of error minimisation, can be calculated from the solution of an extended set of linear algebraic equations. An eigenfunction based model reduction technique is proposed to obtain the coefficient vectors in an efficient way. A numerical example of axial deformation of a rod with fuzzy axial stiffness is considered to illustrate the proposed methods. Linear and nonlinear membership functions are used and the results are compared with direct numerical simulation results.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Adhikari, Professor Sondipon
Authors: Adhikari, S., and Haddad Khodaparast, H.
College/School:College of Science and Engineering > School of Engineering > Infrastructure and Environment
Journal Name:Fuzzy Sets and Systems
Publisher:Elsevier
ISSN:0165-0114
ISSN (Online):1872-6801
Published Online:16 October 2013

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