Linear dynamics of flexible multibody systems : a system-based approach

Jawhar Chebbi (1) , Vincent Dubanchet (1) , José Alvaro Perez Gonzalez (1) , Daniel Alazard (1)

1 DCAS - Département Conception et conduite des véhicules Aéronautiques et Spatiaux

A new methodology to derive the linear model of flexible multibody system dynamics is presented in this paper. This approach is based on the twoport model of each body allowing the model of the whole system to be built just connecting the inputs/outputs of each body model. Boundary conditions of each body can be taken into account through inversion of some input-output channels of its two-port model. This approach is extended here to treat the case of closed-loop kinematic mechanisms. Lagrange multipliers are commonly used in an augmented differential-algebraic equation to solve loop-closure constraints. Instead, they are considered here as a model output, which is connected to the adjoining body model through a feedback. After a summary of main results in the general case, the case of planar mechanisms with multiple uniform beams is considered and the two-port model of the Euler-Bernouilli beam is derived. The choice of the assumed modes is then discussed regarding the accuracy of the first natural frequencies for various boundary conditions. The overall modeling approach is then applied to the well-known four bar mechanism.

Mots clés: Flexible structure; Multibody system; Linear system

Domaines: Autre

Jawhar Chebbi, Vincent Dubanchet, José Alvaro Perez Gonzalez, Daniel Alazard. Linear dynamics of flexible multibody systems : a system-based approach. Multibody System Dynamics, 2016, pp.0. ⟨10.1007/s11044-016-9559-y⟩. ⟨hal-01405184⟩