Numerical study of guided waves in random anisotropic elastic cylinders immersed in fluids

Dispersion characteristics of ultrasonic guided waves, which are commonly used for inspecting prismatic -like structures, may strongly be influenced due to the presence of spatial heterogeneity of material properties. This work presents a probabilistic framework to analyze the dispersion of guided waves in uncertain heterogeneous anisotropic elastic cylindrical structures coupled with fluids. To do so, a random matrix model was employed to introduce the stochastic heterogeneity of elastic properties in the radial direction. The semi -analytical finite element (SAFE) method was used for computing the guided wave dispersion in the considered coupled fluid-elastic system. The proposed method allows to estimate the probability density function of the phase velocity of a specific mode. The numerical results showed that the material's random heterogeneity in a free elastic cylinder may cause a high standard deviation of the phase velocity (up to 6% of the mean value), especially at the point on the dispersion curve where its slope is steep. This effect was shown to be less significant when considering the presence of coupled inner and outer fluids.