Fatigue Analysis of Stochastic Systems Subjected to Cyclic Loading in the Frequency Domain
Ulisses Lima Rosa1; Antônio Marcos G. Lima1
1 Universidade Federal de Uberlândia
doi:10.20906/CPS/USM-2016-0012
Resumo
The design of engineering systems depends on a number of factors, highlighting the environment where it will work and how it will be loaded. The greatest part of tests concerning stresses do not approximate real conditions that most of them are subjected. In the analysis of materials charged with random loadings, the major problem is the material failure by fatigue that occurs with no previous notice and generally on a sudden and catastrophic way. On this case, the characterization of the phenomenon requires application of statistical methods and determination of non-static properties. The interest of this contribution is to describe fatigue in thin plates considering the existence of uncertainties concerned to the structure itself, such as variations on material's elastic properties and geometry. An exact stochastic finite elements method with its discretization obtained by the application of Karhunen-Loève expansions method is developed. Fatigue damage is estimated by the Sines criterion and Monte Carlo Simulation (MCS) combined with Latin Hypercube Sampling is used as the stochastic solver. This process requires stress analysis on Fourier's domain, generating power spectral densities (PSD) of the structure submitted to random loadings. After the theoretical developments, the numerical results obtained by using a thin plate subjected to random multiaxial Gaussian loads are presented.
Palavras-chave: fatigue; frequency stress response; uncertainties; random vibrations; stochastic finite elements