Random vibration analysis of composite beams with six coupled degrees of freedom

Important engineering structures such as wind turbine blades, wings and helicopter rotor blades are modeled as composite beams. Due to the random nature of the excitation in such structures, it is critical to focus on studying the random vibration analysis of composite beams. In this paper, random vibration analysis of composite beams with fully coupled degrees of freedom and damping influences, is presented. Six fully coupled equations of motion are derived and linearized based on an intrinsic formulation. In the presented formulation, non-classical features like shear transverse effects and all material couplings between six beam degrees of freedom are considered. In random vibration analysis, the spectral density and the mean square functions of deflections are derived under random point loadings. The considerable influence of material coupling effects on random response of the structure is observed. The presented analysis can be used to improve the random response of the composite beam-like structures, which have wide application in the industry and engineering.