Bending Vibration in Uncertain Function Gradient Material Structure Through Stochastic Wave Finite Element Method
摘要
This study investigates the multimodal propagation of bending waves in functionally graded material (FGM) beams under intrinsic uncertainties in material and geometric properties. The objective is to quantify their effects on propagation constants and the dispersive behavior of the structure.
MethodsA hybrid stochastic framework combining the Wave Finite Element (WFE) method and probabilistic analysis is developed. Stiffness and mass matrices are derived analytically using Euler–Bernoulli beam theory, capturing bending, shear, and rotational modes with their couplings. These matrices are embedded into the WFE formulation to characterize dispersion curves of a periodic unit cell. Uncertainties are modeled as Gaussian random variables and propagated through Monte Carlo simulations. A stochastic analytical formulation is further introduced to validate numerical predictions.
ResultsThe approach quantifies the variability of dispersion curves, revealing high sensitivity to uncertain input parameters. Both Gaussian and lognormal distributions provide consistent results under moderate variability. The Gaussian model offers sufficient accuracy and simplicity, while the lognormal is theoretically better suited for strictly positive parameters. Monte Carlo simulations, although computationally demanding, remain reliable for validation, while polynomial chaos and stochastic collocation methods enable efficient large-scale analysis.
ConclusionThe proposed stochastic WFE framework effectively characterizes the influence of uncertainties on wave propagation in FGM beams. The results highlight the importance of uncertainty quantification in dispersion studies and demonstrate a balance between computational efficiency and predictive accuracy using complementary stochastic techniques.