Search results for "finite element method"
showing 10 items of 746 documents
Structural damage detection using auto correlation functions of vibration response under sinusoidal excitation
2015
Structural damage detection using time domain vibration responses has attracted more and more researchers in recent years because of its simplicity in calculation and no requirement of a finite element model. This paper proposes a new approach to locate the damage using the auto correlation function of vibration response signals under sinusoidal excitation from different measurement points of the structure, based on which a vector named Auto Correlation Function at Maximum Point Value Vector (AMV) is formulated. A sensitivity analysis of the normalized AMV with respect to the local stiffness shows that under several specific frequency excitations, the normalized AMV has a sharp change aroun…
Simulation of propagation characteristics of ultrasonic guided waves in fractured long bone
2008
Using ultrasonic guided waves (GW) to assess fractures in long bones has gained considerable attention. This paper focuses on using an improved hybrid boundary element method (HBEM) to analyze and calculate reflection coefficients (RC) and transmission coefficients (TC) of low-order GWs for cracks with different depth-to-width ratios (d/w) in fractured long bones. The results showed that the primary received modes, which include the transmitted and reflected modes, are the same as the incident modes. For some values of d/w, the TC of different GW always had local maxima at adjacent frequencies. For some other cracks with different d/w, most of the TC curves had local maxima of which frequen…
Application of Rotational Measurements in Stiffness Reconstruction of Beams and Frames
2009
A stiffness reconstruction method is tested when rotational degrees of freedom are added to the dynamic model of the structure. The inverse problem is formulated as a minimization problem in terms of harmonic vibrations of the structure and its finite element model. An example of frame structure is analyzed by numerical simulations. The results of these numerical analyses show that the damage detection appeared to be much more effective when the angular amplitudes of harmonic vibrations are acquired. This makes very good prospects for the future applications of angular sensors in damage detection of structures.
A computational magnetohydrodynamic model of a marine propulsion system
2016
In this article we present an approach to the description of Magnetohydrodynamic Propulsion. Preliminarly, an analytical model which includes an electromagnetic model and a thermal model is presented. Successively, in order to move beyond the analytical model, a 3-D MHD modeling tool and a Runge Kutta method based solver are presented and they are used to investigate an alternative MHD solutions. Some numerical analysis are given.
STOCHASTIC ANALYSIS OF ONE-DIMENSIONAL HETEROGENEOUS SOLIDS WITH LONG-RANGE INTERACTIONS
2011
Random mass distribution in one-dimensional (1D) elastic solids in the presence of long-range interactions is studied in this paper. Besides the local Cauchy contact forces among adjacent elements, long-range forces depending on the product of interacting masses, as well as on their relative displacements, are considered. In this context, the random fluctuations of the mass distribution involve a stochastic model of the nonlocal interactions, and the random displacement field of the body is provided as the solution of a stochastic integro-differential equation. The presence of the random field of mass distribution is reflected in the random kernel of the solving integro-differential equatio…
An extended Ritz formulation for buckling and post-buckling analysis of cracked multilayered plates
2018
Abstract An extended Ritz formulation for the analysis of buckling and post-buckling behaviour of cracked composite multilayered plates is presented. The formulation is based on: (i) the First-order Shear Deformation Theory to model the mechanics of the multilayered plate; (ii) the von Karman’s theory to account for geometric non-linearities ; (iii) the use of an extended set of approximating functions able to model the presence of an embedded or edge crack and to capture the crack opening fields as well as the global behaviour within a single cracked domain. The numerical results of the buckling analyses and the equilibrium paths in the post-buckling regime are compared with the results fr…
Analysis of Cylindrical Dielectric Resonators in Rectangular Cavities Using a State-Space Integral-Equation Method
2006
In this letter, a state-space integral-equation method in the s-domain has been employed for the accurate analysis of rectangular cavities loaded with cylindrical dielectric resonators. The dielectric obstacles have been treated in terms of their polarization equivalent charge and current densities. The dielectric resonator can be placed at any arbitrary position inside the cavity. The presented technique allows to calculate in a very efficient way a large number of solenoidal modes. The resonant frequencies of dielectric-loaded cavities are calculated and compared with data from literature and a commercial finite element method software, showing a good agreement
A Coupled Solid-Fluid Method for Modeling Subduction
2007
International audience; We present a novel dynamic approach for solid/fluid coupling by joining two different numerical methods: Boundary Element Method (BEM) and Finite Element Method (FEM). FEM results describe the thermo-mechanical evolution of the solid while the fluid is solved with the BEM. The bidirectional feedback between the two domains evolves along a Lagrangian interface where the FEM domain is embedded inside the BEM domain. The feedback between the two codes is based on the calculation of a specific drag tensor for each boundary/finite element. The approach is presented here to solve the complex problem of the descent of a cold subducting oceanic plate into a hot fluid like ma…
Soliton-plasmon resonances as Maxwell nonlinear bound states
2012
We demonstrate that soliplasmons (soliton–plasmon bound states) appear naturally as eigenmodes of nonlinear Maxwell’s equations for a metal/Kerr interface. Conservative stability analysis is performed by means of finite element numerical modeling of the time-independent nonlinear Maxwell equations. Dynamical features are in agreement with the presented nonlinear oscillator model.
Numerical simulation of a wawe generator: A case of study
2013
The aim of present work is the numerical simulation of a linear generator, capable of directly converting the kinetic energy, available by the wave, into electrical energy, through the device linear motion (up and down). In this paper, we intend to propose a numerical simulation approach to immersed devices by applying the Immersed Boundary Method. The Theory of linear wave is used to study and reproduce sea conditions and the computational domain is created based on observations available for the site in which it is envisaged the positioning of the device.