Model uncertainties of flexible structures vibrations induced by internal flows

Abstract

In many situations analysts use incomplete models to design a system, or to make decisions. These models are incomplete due to unmodeled phenomena, which means that some features are not included in the model (either because it was not previously thought about or because it would be too expensive to include). These uncertainties related to the model are difficult to take into account. In this paper, the nonparametric probabilistic approach is used to investigate model uncertainties in the problem of structures excited by internal flow. A reference model is constructed, where an Euler-Bernoulli beam is used to model the structure, and the fluid is added to the model by means of a constant mass, damping and stiffness. Then, an incomplete model of the reference model is considered. In it the influence of the fluid stiffness is not taken into account, hence, the uncertainty is related to this unmodeled feature (fluid stiffness). The incomplete model is then used together with the nonparametric probabilistic approach to infer the behavior of the reference model. Besides, a procedure is proposed to calibrate the dispersion parameter of the probabilistic model.