A NUMERICAL STUDY ON FLAPPING DYNAMICS OF A COMPOSITE LAMINATED BEAM IN SHEAR FLOW

We present a numerical study of the large deflection flapping dynamics of a composite laminated beam in a shear axial flow. A higher-order shear deformation zig-zag theory combined with von Kármán strains is adopted to characterize the geometrical nonlinearity of the composite laminated beam. The finite volume method based on an arbitrary Lagrangian-Eulerian (ALE) approach is employed to solve the Navier-Stokes equation of incompressible viscous fluid. A strongly coupled, partitioned fluid-structure interaction method is adopted to accommodate the dynamic coupling of the two-dimensional shear flow and the laminated beam. The validity of the present method is confirmed by analysing the flapping characteristics of composite laminated beams, which with difference in elasticity between the two layers, subjected to a uniform axial flow. We investigate the effects of shear velocity profile on the flapping characteristics (including limit-cycle oscillation, vortex shedding frequency, and flow pattern) of single isotropic beams and composite laminated beams in a shear axial flow. It is found that with the increase of shear velocity slope, the deflection of the flapping motion neutral axis increases, the standard deviation and dominant frequency of transverse flapping displacement at the beam tip first decrease and then increase. In addition, the differences in the wake vortex modes are discussed. The flapping characteristics of laminated beams with difference in elastic modulus, thickness and ply angle between the two layers are studied. The increase of the difference in elastic modulus changes the symmetry of the laminated beam flapping motion trajectory. Three distinct response regimes are observed depending on the difference in thickness and ply angle between the two layers: fixed-point stable regime, periodic limit-cycle oscillations regime, and aperiodic oscillations regime. The change of thickness ratio of laminated beams makes its vibration regime change from periodic limit cycle oscillations regime to fixed-point stable regime. The increase of the ply angle of laminated beams changes the flapping regime from periodic limit cycle oscillations regime to aperiodic oscillations regime.