The paper deals with the modeling and the development of a numerical procedure for the analysis of shape-memory alloy (SMA) elements in order to predict the main features of SMA devices. A 3D SMA model in the framewor...
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The paper deals with the modeling and the development of a numerical procedure for the analysis of shape-memory alloy (SMA) elements in order to predict the main features of SMA devices. A 3D SMA model in the framework of small strain theory is developed starting from the thermo-mechanical model proposed by Souza et al. (Eur J Mech A/Solids 17:789-806, 1998) and modified by Auricchio and Petrini (Int J Numer Methods Eng 55:1255-1284, 2002). The aim of this paper is to propose some more modifications to the original model, to derive its consistent 1D formulation, to clarify the mechanical meaning of the material parameters governing the constitutive model. A robust time integration algorithm is developed in the framework of the finite element method and a new beam finite element is proposed. Some numerical applications and a comparison with experimental data available in literature are carried out in order to assess the ability of the proposed model to describe the SMA behavior.
The amount of hydrate inhibitor to be injected in the gas processing and transmission system to avoid hydrate formation not only must be sufficient to prevent freezing of the inhibitor in the water phase but also must...
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The amount of hydrate inhibitor to be injected in the gas processing and transmission system to avoid hydrate formation not only must be sufficient to prevent freezing of the inhibitor in the water phase but also must be sufficient to provide for the equilibrium vapor phase content of the inhibitor and the loss of the inhibitor in any liquid hydrocarbon. In this article, a new numerical algorithm is developed for estimation of loss of methanol in paraffinic hydrocarbons at various temperatures and methanol concentrations in the water phase The predicted values showed good agreement with the reported data. The solubility of methanol in paraffin hydrocarbons is calculated for temperatures in the range of 240 to 320K and methanol concentrations up to 70% in the water phase, where the average absolute deviation is around 4%.
The Buckley-James estimator (BJE) [J. Buckley and I. James, Linear regression with censored data, Biometrika 66 (1979), pp. 429-436] has been extended from right-censored (RC) data to interval-censored (IC) data by Ra...
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The Buckley-James estimator (BJE) [J. Buckley and I. James, Linear regression with censored data, Biometrika 66 (1979), pp. 429-436] has been extended from right-censored (RC) data to interval-censored (IC) data by Rabinowitz et al. [D. Rabinowitz, A. Tsiatis, and J. Aragon, Regression with interval-censored data, Biometrika 82 (1995), pp. 501-513]. The BJE is defined to be a zero-crossing of a modified score function H(b), a point at which H(.) changes its sign. We discuss several approaches (for finding a BJE with IC data) which are extensions of the existing algorithms for RC data. However, these extensions may not be appropriate for some data, in particular, they are not appropriate for a cancer data set that we are analysing. In this note, we present a feasible iterative algorithm for obtaining a BJE. We apply the method to our data.
A numerical algorithm for solving the asymptotic stabilization problem by the initial data to a fixed hyperbolic point with a given rate is proposed and justified. The stabilization problem is reduced to projecting th...
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A numerical algorithm for solving the asymptotic stabilization problem by the initial data to a fixed hyperbolic point with a given rate is proposed and justified. The stabilization problem is reduced to projecting the resolving operator of the given evolution process on a strongly stable manifold. This approach makes it possible to apply the results to a wide class of semidynamical systems including those corresponding to partial differential equations. By way of example, a numerical solution of the problem of the asymptotic stabilization of unstable trajectories of the two-dimensional Chafee-Infante equation in a circular domain by the boundary conditions is given.
A simulation algorithm for defining the distribution of eigenvalues of a random symmetric matrix with arbitrary continuous joint probability density function of its entries is presented. The algorithm requires only a ...
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A simulation algorithm for defining the distribution of eigenvalues of a random symmetric matrix with arbitrary continuous joint probability density function of its entries is presented. The algorithm requires only a uniform random number generator. As a numerical example, the probability that eigenvalues of a certain random symmetric matrix satisfy a given condition is calculated using software implementing the algorithm.
The initial boundary value problem for a hyperbolic-type quasilinear equation w(tt) = phi(integral(pi)(0) w(I)(2)dx)w(xx) is considered. Its solution is derived by means of a numerical algorithm consisting of the proj...
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The initial boundary value problem for a hyperbolic-type quasilinear equation w(tt) = phi(integral(pi)(0) w(I)(2)dx)w(xx) is considered. Its solution is derived by means of a numerical algorithm consisting of the projection method and the difference method for approximation with respect to spatial and time variables, while the resulting discrete system is solved by an iteration process. The accuracy of the proposed algorithm is estimated.
A simulation algorithm for defining the distribution of eigenvalues of a random symmetric matrix with arbitrary continuous joint probability density function of its entries is presented. The algorithm requires only a ...
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A simulation algorithm for defining the distribution of eigenvalues of a random symmetric matrix with arbitrary continuous joint probability density function of its entries is presented. The algorithm requires only a uniform random number generator. As a numerical example, the probability that eigenvalues of a certain random symmetric matrix satisfy a given condition is calculated using software implementing the algorithm.
This essay describes seismic damage mechanism of concrete material and a general method induced from a mixed Lagrange approach based on irreversible *** kind of method permits nonlinear effects of geometric,material a...
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This essay describes seismic damage mechanism of concrete material and a general method induced from a mixed Lagrange approach based on irreversible *** kind of method permits nonlinear effects of geometric,material and damage during the catastrophic *** simulate the damage behaviors in concrete materials,the authors make usage of a damage model deduced from a generalized standard material framework. According to the generalized Hamilton principle,the Euler-Lagrange equations of the material and component can be derived from the integral action of generalized standard model based upon Gateaux differentiable form. A numerical implementation technology is exploited to calculate the collapse course of concrete structures.
The paper presents a numerical algorithm used for the solving of the navigation problem in a strap-down inertial system set on a vehicle which has a short mission near by the Earth. The algorithm is divided into two d...
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ISBN:
(纸本)9537044041
The paper presents a numerical algorithm used for the solving of the navigation problem in a strap-down inertial system set on a vehicle which has a short mission near by the Earth. The algorithm is divided into two distinct sequences: the establishing of the vehicle's attitude and the calculation of its speed and position. The introduction comprises the deduction of the quaternionic differential attitude equation. We chose this variant because of the means of calculation: a shorter and quicker way. Moreover, in order to simplify the algorithm an order one Wilcox algorithm was used for the numerical integration of the attitude equation. We mention, though, that for avoiding the commuting errors the acquired gyrometers data will be processed successively on three different channels.
Positioning accuracy of an ultra short baseline (USBL) tracking system is significantly reduced with the increase of alignment errors in the installation of sensors. Although techniques for sensor alignment calibratio...
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Positioning accuracy of an ultra short baseline (USBL) tracking system is significantly reduced with the increase of alignment errors in the installation of sensors. Although techniques for sensor alignment calibration have been developed, they are either complex or lacking in rigor. This study proposes an algorithm to estimate the angular misalignments of a USBL transceiver relative to attitude sensors. The numerical algorithm is based on the positioning errors caused by heading, pitch, and roll misalignments, respectively, when running a circular survey around a seabed transponder. The positioning errors introduced by the angular misalignments outline an iterative scheme of estimating the roll alignment error first, next the heading alignment error, and then finally the pitch alignment error. This makes possible the efficient estimation of all angular misalignments with a high degree of accuracy. With the consideration of measurement error and executing a non-centered and non-perfect circle around the true transponder position, numerical simulations are performed to validate the effectiveness of the proposed algorithm. The simulation results show that the proposed algorithm is robust to the effects of measurement error, non-centered circles, and non-perfect circles. Moreover, the estimates converge fairly quickly, and can be achieved with good accuracy in only a few iterations. (C) 2008 Elsevier Ltd. All rights reserved.
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