Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The spectral element method is used to model a cracked rod, where the crack is modeled as a localized flexibility. The crack flexibility is derived using Castigliano's theorem, and the uncertainties are modeled by the parametric probabilistic approach. The probabilistic model is constructed directly for the variable of interest, i.e., the crack flexibility. Two different probabilistic models, where the probability density functions are constructed using the Maximum Entropy Principle, are used and compared. It is shown that the model with more uncertainty is the one constructed with less information. Monte Carlo simulations are performed in order to estimate the frequency response function envelopes. (C) 2010 Elsevier Ltd. All rights reserved.373326331Tecumseh do BrasilConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPES [086/2008]