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

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 $\widetilde{R}_2$ and $U_1$ could yield the largest contributions to the NEPs provided that they have couplings to both left- and right-handed neutrinos of the order of $O(1)$. For a LQ mass of $1.5$ TeV, the magnetic dipole moment (MDM) of the tau neutrino can be of the order of $10^{-9}$ $\mu_B$, whereas its neutrino electric dipole moment (EDM) can reach values as high as $10^{-20}$-$10^{-19}$ ecm. On the other hand, the NCR can reach values up to $10^{-35}$ cm$^2$ 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 $10^{-14}$ $\mu_B$ 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