1,721,252 research outputs found
Finite deformation analysis of laminated shell via the discontinuous Galerkin method
No full textIn this work, we propose a novel formulation for the large displacements and post-buckling response
analysis of laminated composite shell structures. In order to accurately recover the solution in the case
of multilayered shells, the covariant components of the displacement field are approximated through
the thickness using high-order structural theories. The non-linear two-dimensional total Lagrangian
formulation is obtained starting from the Principle of Virtual Displacements for the three-dimensional
elasticity assuming a linear constitutive relationship between the second Piola–Kirchhoff stress tensor
and the Green-Lagrange strain tensor. The discontinuous Galerkin method is used in combination
with a Newton-Raphson linearization scheme to solve the non-linear problem. High-order elements
are employed to obtain high accuracy with limited computational effort. Several numerical tests are
performed on shell structures with different shapes and lamination sequences. To show the accuracy of
the proposed approach, the results are compared with benchmarks taken from the literature or obtained
using the Finite Element Method available on commercial software
Mixed Finite Elements for multilayered smart plates nonlocal analysis
No full textA mixed finite element formulation for the Eringen’s nonlocal analysis of smart,
magneto-electro-elastic, multilayered plates is presented. Finite elements for different refined higher
order plate layerwise theories are systematically developed. They ensure interface continuity and
allow associating different values of the nonlocal parameter to the laminate layers. Standard 9-node
and 16-node isoparametric, quadrilateral finite elements have been implemented and tested, showing
the characteristics and limitations of the proposed approach
The effect of wildfires on glirids (Muscardinus avellanarius and Glis glis) living in Mediterranean ecosystems
No full textA discontinuous Galerkin formulation for nonlinear analysis of multilayered shells refined theories
Full text linkA novel pure penalty discontinuous Galerkin method is proposed for the geometrically nonlinear analysis of
multilayered composite plates and shells, modelled via high-order refined theories. The approach allows to
build different two-dimensional equivalent single layer structural models, which are obtained by expressing
the covariant components of the displacement field through-the-thickness via Taylor’s polynomial expansion
of different order. The problem governing equations are deduced starting from the geometrically nonlinear
principle of virtual displacements in a total Lagrangian formulation. They are addressed with a pure penalty
discontinuous Galerkin method using Legendre polynomials trial functions. The resulting nonlinear algebraic
system is solved by a Newton–Raphson arc-length linearization scheme. Numerical tests involving plates and
shells are proposed to validate the method, by comparison with literature benchmark problems and finite
element solutions, and to assess its features. The obtained results demonstrate the accuracy of the method as
well as the effectiveness of high-order elements
Impianti di turbina a gas integrati con sistemi di separazione a membrana per la rimozione della CO2
No full text
A non-linear Ritz method for the analysis of low velocity impact induced dynamics in variable angle tow composite laminates
Full text linkVariable angle tow (VAT) laminates feature composite layers reinforced by fibres following continuous curved paths and offer a wide structural design space for the manufacturing of composite components. In this work, a formulation for the analysis of the impact-induced dynamics in VAT laminated plates is proposed, implemented and tested in this work. The method is based on the adoption of first order shear deformation kinematics and includes von Karman non-linear strains. The discrete system is obtained by employing a pb-2 Ritz series expansion into the Hamilton's variational statement, while the impact loading is modelled through Hertzian contact law. The resulting non-linear governing equations are solved using a Newmark time step integration algorithm, coupled with an iterative solution strategy. After validation against available literature data, several tests on different VAT configurations are performed, highlighting analogies and differences between different layups in terms of impact-induced dynamic response
Repowering combined cycle power plants by a modified STIG configuration
No full textAn innovative repowering concept for combined cycle power plants is presented. The design concept consists in adding one or more
gas turbines to the combined cycle, integrated by steam injection into the existing gas turbine. The steam is produced in a simplified heat
recovery steam generator fed by the additional turbine’s exhaust gas. The scheme is quite simple and easy to adapt to various types of
combined cycles. The efficiency of the repowered plant compares favorably with that of the original combined cycle and far surpasses
that obtained by simply adding the gas turbine with no integration. Furthermore, the additional gas turbine enhances the plant operating
flexibility as any power output intermediate between the original and the repowered capacity can be readily attained with no significant
efficiency penalty. A thermodynamic and economic evaluation of the system feasibility is presented
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