105,109 research outputs found
Nonlinear dynamical behaviour of geometrically imperfect microplates based on modified couple stress theory
No full textAbstract not availableHamed Farokhi, Mergen H. Ghayes
Nonlinear size-dependent dynamics of an imperfect shear deformable microplate
No full textAbstract not availableHamed Farokhi, Mergen H. Ghayes
Dynamics of functionally graded micro-cantilevers
No full textAbstract not availableHamed Farokhi, Mergen H. Ghayesh, Alireza Gholipou
Thermo-mechanical dynamics of perfect and imperfect Timoshenko microbeams
No full textAbstract not availableHamed Farokhi, Mergen H. Ghayes
In-plane and out-of-plane motion characteristics of microbeams with modal interactions
No full textThe three-dimensional nonlinear size-dependent motion characteristics of a microbeam are investigated numerically, with special consideration to one-to-one internal resonances between the in-plane and out-of-plane transverse modes. All of the in-plane and out-of-plane displacements and inertia are taken into account and Hamilton's principle, in conjunction with the modified couple stress theory, is employed to obtain the nonlinear partial differential equations governing the motions of the system in the in-plane and out-of-plane directions. The discretization procedure is carried out by applying the Galerkin technique to the partial differential equations of motion, yielding a set of nonlinear ordinary differential equations. A linear analysis is performed upon this set of equations so as to obtain the size-dependent natural frequencies of the system. The nonlinear analysis of the discretized equations of motion is carried out by employing the pseudo-arclength continuation technique, resulting in the resonant responses of the system. It is shown that, due to the presence of one-to-one internal resonances between the in-plane and out-of-plane transverse modes, an in-plane excitation can give rise to an out-of-plane displacement; the internal resonances also cause the occurrence of extra solution branches and new bifurcation points
Three-dimensional nonlinear planar dynamics of an axially moving Timoshenko beam
No full textThe three-dimensional nonlinear planar dynamics of an axially moving Timoshenko beam is investigated in this paper by means of two numerical techniques. The equations of motion for the longitudinal, transverse, and rotational motions are derived using constitutive relations and via Hamilton’s principle. The Galerkin method is employed to discretize the three partial differential equations of motion, yielding a set of nonlinear ordinary differential equations with coupled terms. This set is solved using the pseudo-arclength continuation technique so as to plot frequency-response curves of the system for different cases. Bifurcation diagrams of Poincaré maps for the system near the first instability are obtained via direct time integration of the discretized equations. Time histories, phase-plane portraits, and fast Fourier transforms are presented for some system parameters.Mergen H. Ghayesh, Marco Amabil
Steady-state transverse response of an axially moving beam with time-dependent axial speed
No full textParametric Stability and Bifurcations of Axially Moving Viscoelastic Beams with Time-Dependent Axial Speed#
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