1,722,043 research outputs found
Free vibration analysis of spherical caps using a G.D.Q. numerical solution
No full textAn effective numerical approximated procedure in solving the modal analysis of spherical caps is presented. The technique enlightened in this paper is the Generalized Differential Quadrature Method (G.D.Q.M.), a solving numerical method pertaining to the class of spectral methods. The shell theory used for this study is a first order shear deformation theory with transverse shearing deformations and rotatory inertia included. The shell governing equations in terms of mid-surface displacements are obtained, then, after expansion in partial Fourier series of the longitudinal coordinate, solved with the aim of the G.D.Q.M.. Several comparisons are made with open literature available results, showing the great capability and reliability of the technique in argumen
Effect of boundary conditions on the stability of beams under conservative and non-conservative forces
No full textThis paper, which is an extension of a previous work by Viola et al. (2002), deals with the dynamic stability of beams under a triangularly distributed sub-tangential forces when the effect of an elastically restrained end is taken into account. The sub-tangential forces can be realised by a combination of axial and tangential follower forces, that are conservative and non-conservative forces, respectively. The studied beams become unstable in the form of either flutter or divergence, depending on the degree of non-conservativeness of the distributed sub-tangential forces and the stiffness of the elastically restrained end. A non-conservative parameter α is introduced to provide all possible combinations of these forces. Problems of this kind are usually, at least in the first approximation, reduced to the analysis of beams according to the Bemoulli-Euler theory if shear deformability and rotational inertia are negligible. The equation governing the system may be derived from the extended form of Hamilton's principle. The stability maps will be obtained from the eigenvalue analysis in order to define the divergence and flutter domain. The passage from divergence to flutter is associated with a noticeable lowering of the critical load. A number of particular cases can be immediately recovered
Problems in structural identification and diagnostics: general aspects and applications
No full textThe present volume collects papers illustrating the work done in the research
project MURST MM08342598, within the COFIN Program 2000/2002. The pa-
pers cover the following themes: eects of the modeling errors on the identication
techniques; damage identication from the measurement of frequencies in rods and
beams; node shifting and damage detection; identication of damping and elas-
tic constants in orthotropic plates; use of advanced techniques of signal theory
in structural identication; structural identication of non linear dynamical sys-
tems under random excitation and applications to bridge structures; dynamical
modeling, tests and property identication of building foundations on piles. The
articles were presented at a workshop held in Bologna on July 15-16, 2002, under
the patronage of the Study and Research Centre for the Identication of Materials
and Structures (CIMEST)-\M. Capurso"
The G.D.Q. method for the harmonic dynamic analysis of rotational shell structural elements
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