Stochastic interval analysis for structural natural frequencies based on stochastic hybrid perturbation edge-based smoothing finite element method

Realistically calculating of natural frequencies is crucial for studying dynamical characteristics of structures in engineering. In this paper, the gradient smoothing technique is first applied into the conventional finite element method (named ES-FEM), to improve the accuracy of the deterministic calculation of natural frequencies. Then, the hybrid random and interval uncertain parameters are introduced into the proposed ES-FEM based on hybrid stochastic and interval perturbation method. Expressions for the mean value and variance of natural frequencies are derived by combining the random interval perturbation method and the random interval moment method. The upper and lower bounds of mean value and variance of natural frequencies are calculated based on hybrid perturbation vertex method. The proposed method (denoted ESHPVM) is compared with the different methods. The high accuracy and efficiency of the proposed methods are verified by two numerical examples.