Search results for "T method"
showing 10 items of 1254 documents
A one-dimensional model for dynamic analysis of generally layered magneto-electro-elastic beams
2013
Abstract A new one-dimensional model for the dynamic problem of magneto-electro-elastic generally laminated beams is presented. The electric and magnetic fields are assumed to be quasi-static and a first-order shear beam theory is used. The electro-magnetic problem is first solved in terms of the mechanical variables, then the equations of motion are written leading to the problem governing equations. They involve the same terms of the elastic dynamic problem weighted by effective stiffness coefficients, which take the magneto-electro-mechanical couplings into account. Additional terms, which involve the third spatial derivative of the transverse displacement, also occur as a result of the …
Finite-Element Formulation of a Nonlocal Hereditary Fractional-Order Timoshenko Beam
2017
AbstractA mechanically-based nonlocal Timoshenko beam model, recently proposed by the authors, hinges on the assumption that nonlocal effects can be modeled as elastic long-range volume forces and moments mutually exerted by nonadjacent beam segments, which contribute to the equilibrium of any beam segment along with the classical local stress resultants. Long-range volume forces/moments linearly depend on the product of the volumes of the interacting beam segments, and on pure deformation modes of the beam, through attenuation functions governing the space decay of nonlocal effects. This paper investigates the response of this nonlocal beam model when viscoelastic long-range interactions a…
Metallurgical Evolutions in Hot Forging of Dual Phase Titanium Alloys: Numerical Simulation and Experiments
2015
Titanium forging has been encountering a growing interest in the scientific and industrial communities because of the distinct advantages it provides with respect to machining, in terms of both mechanical properties of the product and material waste, thus significantly reducing the Buy to Fly ratio. In the paper, a numerical FE model, based on a tri-coupled approach and able to predict the microstructural evolutions of the workpiece during the process, is developed and set up. Calculated results are compared to experiments for a few industrial case studies. The final phases distribution in the forged parts is experimentally measured and compared to the FE model output finding satisfying ove…
Development of helium coolant DEMO first wall model for SYCOMORE system code based on HCLL concept
2018
Abstract The conceptual design of the demonstration fusion power reactor, known as DEMO, is ongoing and several reactor configurations have to be investigated by exploring different design parameters. For these reasons, within the European framework, systems codes like SYCOMORE (SYstem COde for MOdelling tokamak REactor) have been developed. SYCOMORE includes several specific modules, one of which is aimed to define a suitable design of the helium breeding blanket. The research activity has been devoted to improve the method to define automatically the First Wall design starting from thermal-hydraulic and thermo-mechanical considerations, using analytical design formulae and, also, taking i…
A genetic algorithm for combined topology and shape optimisations
2003
A method to find optimal topology and shape of structures is presented. With the first the optimal distribution of an assigned mass is found using an approach based on homogenisation theory, that seeks in which elements of a meshed domain it is present mass; with the second the discontinuous boundaries are smoothed. The problem of the optimal topology search has an ON/OFF nature and has suggested the employment of genetic algorithms. Thus in this paper a genetic algorithm has been developed, which uses as design variables, in the topology optimisation, the relative densities (with respect to effective material density) 0 or 1 of each element of the structure and, in the shape one, the coord…
TOPOLOGY OPTIMIZATION OF A CONNECTING ROD FOR AN INTERNAL COMBUSTION ENGINE
2009
The topology optimization of a structure is a process that allows to establish if in a point of an assigned domain there should be some material. No assumption is made with regard to the number and the distribution of the contours and the final topology, that can be very different compared to that one initially hypothesized. In this paper a study related to the topology optimization of a connecting rod for an internal combustion engine is presented. The used technique for the optimization is the density (or distribution of material) method. The developed application, besides giving an innovative solution of the topology of the connecting rod with a lower mass in comparison with the initial …
On the numerical assessment of the thermo-mechanical performances of the DEMO Helium-Cooled Pebble Bed breeding blanket module
2014
Within the framework of the European DEMO Breeder Blanket Programme, a research campaign has been launched by University of Palermo, ENEA-Brasimone and Karlsruhe Institute of Technology to theoretically investigate the thermo-mechanical behavior of the Helium-Cooled Pebble Bed (HCPB) breeding blanket module of the DEMO1 blanket vertical segment, under normal operation and over-pressurization loading scenarios. The research campaign has been carried out following a theoretical-computational approach based on the finite element method (FEM) and adopting a qualified commercial FEM code. A realistic 3D FEM model of the HCPB blanket module central poloidal-radial region has been developed, inclu…
A Teaching Experience: Aeroelasticity and the Finite Element Method
2015
[EN] The aeroelastic modelling of aircraft structures is a fundamental area for the students of Aerospace Engineering Degree. This subject has a strongly multidisciplinary character and involves other several subjects like mechanics, vibrations, aerodynamics, structural analysis. Consequently, the students find stimulating the challenge of merging their knowledge at different areas. In this paper, a teaching experience on the solution of the aeroelastic problem of a 3D-wing through six different computer tasks is presented. The main objective is to attempt a relatively complex problem using a simple version of the Finite Element Method with only four degrees of freedom. The students begin c…
Multilayer neural networks: an experimental evaluation of on-line training methods
2004
Artificial neural networks (ANN) are inspired by the structure of biological neural networks and their ability to integrate knowledge and learning. In ANN training, the objective is to minimize the error over the training set. The most popular method for training these networks is back propagation, a gradient descent technique. Other non-linear optimization methods such as conjugate directions set or conjugate gradient have also been used for this purpose. Recently, metaheuristics such as simulated annealing, genetic algorithms or tabu search have been also adapted to this context.There are situations in which the necessary training data are being generated in real time and, an extensive tr…
Symmetric Galerkin BEM for Non Linear Analysis of Historical Masonries
2015
The preservation of the historical and monumental buildings, but also of the considerable heritage of old constructions made by traditional techniques, is one of the actual problems of the structural mechanics. The level of knowledge of their structural behavior in presence of external actions is made through calculus methods and simple procedures in order to allow a reading of the material suffering degree and as a consequence of the related safety. Unfortunately, often the masonry panels show openings located in an irregular way and cracks having small or big dimensions. In these cases the employment of strategies, as for example the identifying of the masonry piers and the transformation…