UNCERTAINTIES IN WAVE CHARACTERISTIC OF TWO-DIMENSIONAL PERIODIC MEDIA USING THE FUZZY WAVE FINITE ELEMENT METHOD

The periodic structures exhibit a considerable amount of scattering in material properties during the manufacturing process and mechanical properties evaluations. Due to imprecision and nonavailability of the information about the parameter, the uncertainty is modelled as fuzzy variable. In this paper wave finite element method in conjunction with fuzzy logic and algebra defined as fuzzy wave finite e lement method h as b een a pplied f or f ree wave p ropagation i n t he two-dimensional periodic structure. The formulation is derived for the direct form where frequency is imposed, and wavenumber dispersion is obtained. The dispersion curves for the out of plane flexural waves with fuzzy parameters have been used to illustrate the proposed approach. In the numerical simulation, target is to look for the possibility to find the variation of the frequency band gap (frequency region, where waves cannot propagate). The validation of the presented method is carried out for the free wave propagation for the periodic plate by comparison with WFEM MCS results.