A comparison of models for uncertainty analysis by the finite element method

Uncertainty in structural engineering analysis exists in the architecture of a structural system, its basic parameters, the information resulting from the abstracted aspects of the system, and the non-abstracted or unknown aspects of the system. Also, uncertainty is present as a result of prediction models, analysis and design of structures, and general lack of knowledge about the behavior of real structures. One of the important factors that lead to errors in numerical predictions is the degree of precision in obtaining the relevant parameters. In this paper we discuss two different methodologies: 1. Classical probabilistic approach, in which the properties are treated as random variables. Stochastic Finite Element Methods are examined using both Monte Carlo Simulation and Perturbation Methods. 2. Possibilistic approach, by a model based on the theory of fuzzy sets. Some results are presented to point out the main characteristics of the two methodologies (Lima, D.Sc. Thesis, COPPE/Federal University Rio de Janeiro, 1996). (C) 2000 Elsevier Science B.V. All rights reserved.