Copyright © A.Di Egidio
Thin walled beam
A model of thin walled open cross-section beam, taking into account the nonlinear effects of torsional warping has been proposed.
It has been obtained by an appropriate generalization in the nonlinear field of the Vlasov theory. The dynamics of a mechanical model
exibiting several internal resonace conditions, when forced by an armonic load has been studied in deep.
An analytical, numerical and experimental investigation on a channel cantilever beam has been conducted to validate the proposed model
and overall to better understand the nonlinear contributions due to warping and torsional elongation effects. A simplified model,
obtained under the hypotesis that the torsional curvature is greater of the flexural ones, allowed us to understand in deep the
role of the nonlinear new terms in the static behaviour and the flexural-torsional instability of the beam.
Fig. 2.1: Beam section before and after deformation
Fig. 2.2: Experimental setup
UNIVERSITY OF L'AQUILA - ITALY
Thin walled beams
An open-cross section thin-walled beam model, already developed by the Authors, has been conveniently simplified while maintaining
the capacity of accounting for the significant nonlinear warping effects. For a technical range of geometrical and mechanical characteristics
of the beam, the response is characterized by the torsional curvature prevailing over the flexural ones. The attention has been focused
on the dynamic response of the beam to a harmonic force, applied at the free end of the cantilever beam. The stability of the
one-component oscillations has been investigated using the analytical model, showing the importance of the internal resonances due
to the nonlinear warping coupling terms. Comparison with the results provided by a computational finite element model has been performed.
Fig. 2.3: Bifurcation diagrams
D.I.C.E.A.A. - Dipartimento di Ingegneria Civile, Edile-Architettura e Ambientale
