Consistent structural linearisation in flexible-body dynamics with large rigid-body motion

A consistent linearisation, using perturbation methods, is obtained for the structural degrees of freedom of flexible slender bodies with large rigid-body motions. The resulting system preserves all couplings between rigid and elastic motions and can be projected onto a few vibration modes of a reference configuration. This gives equations of motion with cubic terms in the rigid-body degrees of freedom and constant coefficients which can be pre-computed prior to the time-marching simulation. Numerical results are presented to illustrate the approach and to show its advantages with respect to mean-axes approximations.

► Beam kinematics with large rigid-body motions and small deformations. ► An assessment of all inertial couplings between degrees of freedom. ► Modal form of the equations of motion in terms with nonlinear rigid-body dynamics. ► Improvements shown with respect to mean axes approach used in flight dynamics.