Helicopter vibration reduction in forward flight with induced-shear based piezoceramic actuation

Abstract

Governing equations are obtained for helicopter rotor blades with surface bonded piezoceramic actuators using Hamilton’s principle. The equations are then solved for dynamic response using finite element discretization in the spatial and time domains. A time domain unsteady aerodynamic model is used to obtain the airloads. The nonlinear relationship between the piezoelectric shear coefficient and applied ac field is represented as a polynomial curve fit. The nonlinear effects are investigated by applying a sinusoidal voltage to the helicopter rotor blade. The rotor blade is modeled as a two-cell box section with piezoelectric layers surface bonded to the top and bottom of the box beam. Comparison of results with linear and nonlinear shear coefficients is presented. Use of a nonlinear relationship (compared to linear) to achieve targeted reductions in strains or displacements results in a reduction in the requirement of applied amplitude of the sinusoidal field. A rate feedback control law is implemented which feeds back the higher harmonics of the time rate of change of strain in the azimuthal direction. The sensed voltage is then applied to the rotor blade, resulting in a vibration reduction of approximately 43% for a four-bladed, soft-in-plane hingeless rotor in forward flight.

Piezoelectric d15shear response-based torsion actuation mechanism: an experimental benchmark and its 3D finite element simulation

“…This torsion actuation mechanism (TAM) was achieved experimentally using tubular actuators assembled from eight segments that were cut from circumferentially-polarized piezoceramic tubes [9][10][11], and theoretically using symmetrically surface-bonded width-polarized patches [12,13]. A simulation benchmark (theoretical) was also recently proposed consisting of a cantilever long and thin beam consisting of two piezoceramic layers oppositely-polarized (OP) along their length and superposed along their width [14].…”

A mathematical model in three-dimensional piezoelectric continuum to predict non-linear responses of piezoceramic materials

“…requires a thorough understanding of the piezoelectric material behaviour at different applied electrical and mechanical fields. Though the non-linearities under strong electric fields such as dielectric and butterfly hysteresis have drawn the attention of many authors recently [2][3][4][5][6][7], the modelling of non-linear behaviour of piezoceramics under weak electric fields is limited in literature. With a number of piezoelectric finite-element (FE) models existing in the literature to cope with complicated boundary problems of smart structures, it is very important to develop a simple procedure to obtain analytical solutions for a few simple geometries for verification of finite-element formulations and also to gain confidence in the procedure.…”

Nonlinear Dynamic Analysis of Macrofiber Composites Laminated Shells

“…Theoretical analyses are the basis to obtain dynamical characteristics of MFC material subjected to different excitations. In some researches, piezoelectric characteristics of MFC are studied by nonlinear constitutive equations and numerical simulation, including higher-order terms and corresponding coefficients [5][6][7] or by using strain dependent or effective piezoelectric coefficients in constitutive equations [8][9][10][11].…”