Uncertain structural free vibration analysis with non-probabilistic spatially varying parameters

The uncertain free vibration analysis of engineering structures with the consideration of non-stochastic spatially dependent uncertain parameters is investigated. A recently proposed concept of interval field is implemented to model the intrinsic spatial dependency of the uncertain-but-bounded system parameters. By employing the appropriate discretisation scheme, evaluations of natural frequencies for engineering structures involving interval fields can be executed within the framework of the finite element method (FEM). Furthermore, a robust, yet efficient, computational strategy is proposed such that the extreme bounds of natural frequencies of the structure involving interval fields can be rigorously captured by performing two independent eigen-analyses. Within the proposed computational analysis framework, the traditional interval arithmetic is not employed so that the undesirable effect of the interval overestimation can be completely eliminated. Consequently, both sharpness and physical feasibility of the results can be guaranteed to a certain extent for any discretised interval field. The plausibility of the adopted interval field model, as well as the feasibility of the proposed computational scheme, are clearly demonstrated by investigating both academic sized and practically motivated engineering structures.