1,487 research outputs found
Nonlinear dynamics of buckling-restrained braces with axially graded core in elastic regime
No full textNonlinear dynamics of a slender axially graded beam embedded in a viscoelastic medium
No full textIn the present contribution the nonlinear dynamics of beams under axial time-dependent excitation is studied. The beams, which are embedded in a linear viscoelastic medium, are assumed as axially graded in terms of material properties. The transversal motion equation is derived under two main hypotheses, namely the beams satisfy the requirements of Euler-Bernoulli theory and undergo moderately large deflections.</jats:p
Numerical applications of free discontinuity problems to folding and fracture
No full textThe aim of the thesis is the application of new numerical methods based on the theory of free discontinuities of E. De Giorgi to challenging fields of relevant practical interest in engineering, such as folding of thin walled tubes and propagation of fracture in brittle solids. Both the mathematical models to describe folding and fracture are based on the minimization of two competing energy forms: a volume and a surface energy. The variational formulation leads to the minimization (under displacement boundary conditions) of a functional F(K;u), where K is the set of discontinuous points of u. In order to perform the numerical search for the minimum of F, a powerful open code (developed by K. Brakke) named Surface Evolver has been adapted according to the purposes of the research at hand. Since the energy is non-convex the solution obtained through the algorithm is strongly dependent on the initial point. Starting from an initial faceted surface, the numerical code evolves the surface towards minimum energy through the nonlinear conjiugate gradient method
A damping device based on bistable springs
No full textA device for earthquake energy dissipation in shear–
type structures is introduced. The idea is basically to employ
chains made of bistable springs, that exhibit hysteretic behavior
Dynamics of an axially functionally graded beam under axial load
No full textThis paper considers the dynamics of a simply supported
beam under axial time–dependent load. The beam is made of an axially
functionally graded material. The motion equations are deduced
from the equilibrium in deformed configuration and no restriction is
made on the amplitude of the transversal displacement, but that naturally
imposed by the inextensibility assumption that is adopted in the
present study. The transversal motion equation, that is a partial differential
equation, is approximated by its Taylor expansion until third
order and then discretized through the Galerkin procedure
On the Effect of Axial Material Gradation on the Dynamics of a Slender Beam in a Viscoelastic Medium
No full textDynamics of Functionally Graded Beams on Viscoelastic Foundation
No full textIn the present contribution, the nonlinear dynamics of beams under axial time-dependent
excitation is studied. The beams, which rest on a linear viscoelastic foundation, are assumed as
axially graded both in terms of geometrical and material properties. The transversal motion
equation is derived under two main hypotheses, namely the beams satisfy the requirements of
Euler–Bernoulli theory and undergo moderately large de°ections (MLDs)
Consequences of different definitions of bending curvature on nonlinear dynamics of beams
No full textOn the notion of curvature and its mechanical meaning in a geometrically exact plane beam theory
No full text
- …
