6,461 research outputs found
Coupled thermo-mechanical finite element models with node-dependent kinematics for multi-layered shell structures
Node-dependent Kinematic (NDK) shell finite element (FE) formulations are presented for the steady-state thermo-mechanical analysis of laminated structures. The displacements and temperature change are treated as primary variables in the FE models and are directly solved through the coupled thermo-mechanical models. The enforcement of distributed temperature boundary conditions on the top or the bottom surface of hierarchical shell elements is conducted through the Linear Least Squares. The effectiveness of the proposed FE approaches is verified by comparing the results against those from the literature. The application of adaptive refinement approach based on the hierarchical elements and NDK to build FE models with optimal efficiency is demonstrated through numerical examples
A MULTILAYERED PLATE ELEMENTS ACCOUNTING NODE-DEPENDENT KINEMATICS FOR STATIC ANALYSIS OF PIEZOELECTRIC STRUCTURES
Effect of Nonstructural Masses on Civil Structures by CUF-Based Finite Element Models
This paper proposes an application of already established higher-order models and, namely,
investigates the free vibration analysis of civil engineering structures subjected to nonstructural
masses. The refined one-dimensional theories adopted are based on the Carrera unified
formulation (CUF). The stiffness and mass matrices are obtained by means of the
principle of virtual displacements in conjunction with the finite element method (FEM).
According to CUF, in fact, their formulation is performed in terms of fundamental nuclei,
which depend neither on the adopted class of beam theory nor on the FEM approximation
along the axis. In order to account for nonstructural localised masses, the fundamental
nucleus of the mass matrix has been opportunely modified. In this work, Lagrange polynomials
have been employed in the framework of CUF to develop pure translational displacement-
based refined beam models. The models obtained using this approach are referred, in
the literature, to as component wise (CW), which allows to model each structural component
as a 1D element. The free vibration analysis has been carried out for different cases of
nonstructural mass distribution in typical civil buildings. The results obtained are compared
with classical Solid/Shell FEM solutions from the commercial code MSC Nastran. The capabilities
of the CW models are demonstrated, since this formulation is able to replicate the 3D
solid results with enhanced performances in terms of computational efforts. Moreover, the
importance of taking into account the correct distribution of the nonstructural masses is
shown to be of fundamental importance in vibration analysis of civil buildings
Neutrino charge radius and electromagnetic dipole moments via scalar and vector leptoquarks
The one-loop contribution of scalar and vector leptoquarks (LQs) to the
electromagnetic properties (NEPs) of massive Dirac neutrinos is presented via
an effective Lagrangian approach, with emphasis on the effective neutrino
charge radius (NCR), which has never been calculated and is obtained by the
background field formalism in a Yang-Mills-like scenario for gauge LQs.
Analytical results for nonzero neutrino mass are presented in terms of both
Feynman-parameter integrals and Passarino-Veltman scalar functions, which can
be useful to obtain the NEPs of heavy neutrinos, out of which approximate
expressions are obtained for light neutrinos. For the numerical analysis we
concentrate on the only renormalizable scalar and vector LQ representations
that do not need extra symmetries to forbid tree-level proton decay.
Constraints on the parameter space consistent with current experimental data
are then discussed and it is found that the LQ representations
and could yield the largest contributions to the NEPs
provided that they have couplings to both left- and right-handed neutrinos of
the order of . For a LQ mass of TeV, the magnetic dipole moment
(MDM) of the tau neutrino can be of the order of , whereas its
neutrino electric dipole moment (EDM) can reach values as high as
- ecm. On the other hand, the NCR can reach values up to
cm regardless of the neutrino flavor and even in the absence of
right-handed neutrinos. In the latter scenario, the EDM vanishes and the
contribution to neutrino MDM would be negligible, of the order of
for the tau neutrino, whereas those for the muon and electron neutrinos
would be about two and seven orders of magnitude smaller, respectively. Our
estimates could be severely suppressed due to a possible suppression of the LQ
coupling constants.Comment: 31 pages, 11 figure
- …