Search results for "Finite element method"
showing 10 items of 746 documents
Finite-Element Modeling of Floodplain Flow
2000
A new methodology for a robust solution of the diffusive shallow water equations is proposed. The methodology splits the unknowns of the momentum and continuity equations into one kinematic and one parabolic component. The kinematic component is solved using the slope of the water level surface computed in the previous time-step and a zero-order approximation of the water head inside the mass-balance area around each node of the mesh. The parabolic component is found by applying a standard finite-element Galerkin procedure, where the source terms can be computed from the solution of the previous kinematic problem. A simple 1D case, with a known analytical solution, is used to test the accur…
Coaxial Slot Antenna Design for Microwave Hyperthermia using Finite- Difference Time-Domain and Finite Element Method
2011
Hyperthermia also called thermal therapy or thermotherapy is a type of cancer treatment in which body tissue is exposed to high temperatures. Research has shown that high temperatures can damage and kill cancer cells, usually with minimal injury to normal tissues. Otherwise, ablation or high temperature hyperthermia, including lasers and the use of radiofrequency, microwaves, and high-intensity focused ultrasound, are gaining attention as an alternative to standard sur- gical therapies. The electromagnetic microwave irradiation applied to the tumor tissue causes water molecules to vibrate and rotate, resulting in tissue heating and subsequently cell death via thermal-induced protein denatur…
On the thermo-mechanical behaviour of the IFMIF target assembly under steady state and transient operative scenarios
Bòvedas tabicadas: experimental and numerical analysis
2008
A class of thin vaults, the so-called “bovedas tabicadas”, which represent one of the most common Spanish traditional building techniques at the end of XIX century are studied here, treating the relevant analysis problem through a numerical, as well as an experimental, approach. At first the problem is studied by searching for the behaviour of the material effecting suitable experiments. Once the constitutive behaviour of the materials and the structural elements are experimentally characterized, a semi inverse method for the identification of the optimum mechanical parameters to assign to an equivalent homogeneous ideal material through analysis reproducing the executed experimental tests …
Effect of platform switching on the peri-implant bone: A finite element study
2015
Background: There exists a relation between the presence and location of the micro-gap and the loss of peri-implant bone. Several authors have shown that the treatments based on the use of platform switching result in less peri-implant bone loss and an increased tissue stability. The purpose of this study was to analyse the effect of the platform switching on the distribution of stresses on the peri-implant bone using the finite element method. Material and Methods: A realistic 3D full-mandible finite element model representing cortical bone and trabecular bone was used to study the distribution of the stress on the bone induced by an implant of diameter 4.1 mm. Two abutments were modelled.…
Definition of a fiber macro-model for nonlinear analysis of infilled frames
2017
A common way to model infill-frame interaction is the use equivalent strut macromodels. In most cases these are compression only resistant truss elements defined with a multi-linear axial-force / axial-displacement law. The main difficulty in using this approach is to correctly calibrate such a force-displacement curve (slope of ascending and post-peak branches, critical yielding, peak and residual forces) because of the large number of variables (mechanical and elastic properties of materials) and the different possible damage mechanisms activated for the frame-infill system. Another possible way is using fiber-section elements as diagonal struts. In this case the force-displacement law is…
Numerical study and comparisons with experimental data for transient behaviour of phase boundaries during industrial FZ process for silicon crystal g…
2005
Abstract In our numerical transient model developed previously for the industrial FZ crystal growth process with the needle-eye technique, the meshing algorithms are essentially improved and a significant amount of numerical studies are carried out for model verification. Transient modelling for the experimental growth process with step-like time dependences of inductor current and feed rod velocity has shown that time dependencies of the crystal radius and zone height calculated numerically agree with the data from praxis. The fully transient simulation for growth process of crystal starting cone has shown that the model is capable of performing the simulation even if the crystal diameter …
Un élément fini mixte tridimensionnel pour le calcul des contraintes d'interface
1999
ABSTRACT In this paper we present an interfacial finite element designed for analysing planar interfaces in a three-dimensional approach. The element is derived from Hellinger-Reissner's mixed variational principle and takes into account the continuity of the displacement and of the transverse stress components through the interface. Stress analysis of a sandwich plate is made to assess the validity and the effectiveness of the element models, with comparisons to closed-form and numerical solutions.
Experimental and numerical evaluation of sandwich composite structures
2004
The main problem working with sandwich composite structures is their intrinsic anisotropy and non-homogeneity that does not allow their correct modelling. Nowadays the available data on mechanical properties of complex structures, necessary to allow a correct and reliable design, are not sufficient. The aim of the present work is to extend the knowledge of mechanical properties both on single components and on complete structures, focusing on the effects induced by different kind of skin arrangements (Kevlar, glass and carbon fibres). Compressive, shear and flexural tests were performed for a complete static mechanical characterisation of the sandwich structure both on each single component…