Dynamics of reticulated structures: Evidence of atypical gyration modes
Résumé
This paper deals with the dynamic behavior of periodic reticulated beams made of symmetric unbraced framed cells. Such archetypical cells can present a high contrast between shear and compression deformabilities that opens the possibility of enriched local kinematics. Through the homogenization method of periodic discrete media associated with a systematic use of scaling, the existence of atypical gyration modes is established theoretically. These latter modes appear when the elastic moment is balanced by the rotation inertia, conversely to natural modes where the elastic force is balanced by the translation inertia. A generalized beam modeling including both natural and gyration modes is proposed and discussed through a dimensional analysis. The results are confirmed on numerical examples.