Reliability Indexes Calculation of Industrial Boilers Under Stochastic Thermal Process

1998 ◽  
Author(s):  
Olivier Rollot ◽  
Maurice Pendola ◽  
Maurice Lemaire ◽  
Igor Boutemy
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Element Methods ◽  
Thermal Process ◽  
Complex Structures ◽  
The Finite Element Method ◽  
Random Data ◽  
Electric Company ◽  
New Methods ◽  
Industrial Boilers

Abstract This text sums up a research for the French Electric Company, EDF, which wants to know the influence of the temperature variability on the reliability of some of their boilers. These boilers are very complex structures whose behavior has to be modelized by the Finite Element Method, FEM. This work is an application of Finite Element Methods in a reliability context, that means the introduction of random data into a classical FEM, in order to determine the reliability of the structures. These random data may concern geometry, material characteristics of the structures or the loads the structure may carry. Then, it’s necessary to employ new methods to take into account these stochastic approaches and to obtain more efficient decision’s elements for a better control of the boilers.

Convergence analysis of a finite element method for second order non-variational elliptic problems

2017 ◽  
Vol 25 (3) ◽  
Author(s):  
Michael Neilan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Partial Differential Equations ◽  
Convergence Analysis ◽  
Finite Element Methods ◽  
Elliptic Partial Differential Equations ◽  
The Finite Element Method ◽  
Variational Form ◽  
The One ◽  
Element Method

AbstractWe introduce and analyze a family of finite element methods for elliptic partial differential equations in non-variational form with non-differentiable coefficients. The finite element method studied is a variant of the one recently proposed in [Lakkis & Pryer,

Finite Element Analysis to a Kind of Elliptic Variational Inequality

2012 ◽  
Vol 557-559 ◽  
pp. 2126-2129
Author(s):  
Jun Hui Zhu ◽  
Chun Rui Cheng ◽  
Guang Pu Lou
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Variational Inequality ◽  
Error Estimate ◽  
Finite Element Methods ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Nonlinear Materials ◽  
Elliptic Variational Inequality

Finite element methods for the elliptic variational inequality of the second kind deduced from friction problems or nonlinear materials in elasticity have been discussed. In this paper, the finite element method with numerical integration for the second type elliptic variational inequality is considered and an error estimate is proved.

scholarly journals Multimodeling of multi-alterated structures in the Arlequin framework

2008 ◽  
pp. 969-980
Author(s):  
Hachmi Ben Dhia ◽  
Nadia Elkhodja ◽  
François-Xavier Roux
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Simple Structure ◽  
Low Cost ◽  
Numerical Results ◽  
Complex Structures ◽  
The Finite Element Method ◽  
Low Costs ◽  
Element Method

The goal of this work is the development of a numerical methodology for flexible and low-cost computation and/or design of complex structures that might have been obtained by a multialteration of a sound simple structure. The multimodel Arlequin framework is herein used to meet the flexibility and low-costs requirements. A preconditioned FETI-like solver is adapted to the solution of the discrete mixed Arlequin problems obtained by using the Finite Element Method. Enlightening numerical results are given.

scholarly journals The optimal dimensions of the domain for solving the single-band Schrödinger equation by the finite-difference and finite-element methods

2014 ◽  
Vol 11 (1) ◽  
pp. 73-84 ◽  
Author(s):  
Dusan Topalovic ◽  
Stefan Pavlovic ◽  
Nemanja Cukaric ◽  
Milan Tadic
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Finite Element Methods ◽  
Ground State ◽  
Difference Method ◽  
Grid Size ◽  
The Finite Element Method ◽  
The Finite Difference Method

The finite-difference and finite-element methods are employed to solve the one-dimensional single-band Schr?dinger equation in the planar and cylindrical geometries. The analyzed geometries correspond to semiconductor quantum wells and cylindrical quantum wires. As a typical example, the GaAs/AlGaAs system is considered. The approximation of the lowest order is employed in the finite-difference method and linear shape functions are employed in the finite-element calculations. Deviations of the computed ground state electron energy in a rectangular quantum well of finite depth, and for the linear harmonic oscillator are determined as function of the grid size. For the planar geometry, the modified P?schl-Teller potential is also considered. Even for small grids, having more than 20 points, the finite-element method is found to offer better accuracy than the finite-difference method. Furthermore, the energy levels are found to converge faster towards the accurate value when the finite-element method is employed for calculation. The optimal dimensions of the domain employed for solving the Schr?dinger equation are determined as they vary with the grid size and the ground-state energy.

scholarly journals Calculation and Improvement of Complex Mechanical Properties of the Mega Arch Dam under Multiple Loads Based on Finite Element Methods

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Chenghua Fu ◽  
Hongbo Zhou ◽  
Yanfang Pan
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Finite Element Methods ◽  
Seismic Waves ◽  
Arch Dam ◽  
Dynamic Responses ◽  
The Finite Element Method ◽  
Effective Measure ◽  
Multiple Loads

Researches on dynamic responses of the arch dam under seismic waves were not systematic and perfect enough in published papers. They rarely proposed measures to improve the antiseismic performance of the arch dam under seismic waves. Based on the finite element method, this paper completed a systematic and perfect research on stress and damage of the arch dam under seismic waves and proposed an effective measure to improve the antiseismic performance. The computed results of the improved arch dam were compared with the original one. Results proved that improved effects are obvious. In addition, damage stabilization value of the improved arch dam was 0.47, while the original one was 0.13. Obviously, the safety of the improved arch dam under the same loads was higher. Damage of the improved arch dam was increased by stages. It took about 3 s from zero damage to the complete damage, while the time was about only 1.3 s for the original one. Obviously, the antidamage capability of the improved arch dam was better. The improved measure proposed in this paper is very effective. This paper provides one reference for studying and improving the antiseismic performance of the arch dam.

scholarly journals Optimal parameter for the stabilised five-field extended Hu–Washizu formulation

2020 ◽  
Vol 61 ◽  
pp. C197-C213
Author(s):  
Muhammad Ilyas ◽  
Bishnu P. Lamichhane
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Element Methods ◽  
Mixed Finite Element ◽  
Mixed Finite Element Method ◽  
The Finite Element Method ◽  
Biorthogonal Systems ◽  
Poisson Problem ◽  
Engineering Mathematics ◽  
Element Method

We present a mixed finite element method for the elasticity problem. We expand the standard Hu–Washizu formulation to include a pressure unknown and its Lagrange multiplier. By doing so, we derive a five-field formulation. We apply a biorthogonal system that leads to an efficient numerical formulation. We address the coercivity problem by adding a stabilisation term with a parameter. We also present an analysis of the optimal choices of parameter approximation. References I. Babuska and T. Strouboulis. The finite element method and its reliability. Oxford University Press, New York, 2001. https://global.oup.com/academic/product/the-finite-element-method-and-its-reliability-9780198502760?cc=au&lang=en&. D. Braess. Finite Elements: Theory, Fast Solvers, and Applications in Solid Mechanics. Cambridge University Press, Cambridge, UK, 3rd edition edition, 2007. doi:10.1017/CBO9780511618635. J. K. Djoko and B. D. Reddy. An extended Hu–Washizu formulation for elasticity. Comput. Meth. Appl. Mech.Eng. 195(44):6330–6346, 2006. doi:10.1016/j.cma.2005.12.013. J. Droniou, M. Ilyas, B. P. Lamichhane, and G. E. Wheeler. A mixed finite element method for a sixth-order elliptic problem. IMA J. Numer. Anal. 39(1):374–397, 2017. doi:10.1093/imanum/drx066. M. Ilyas. Finite element methods and multi-field applications. PhD thesis, University of Newcastle, 2019. http://hdl.handle.net/1959.13/1403421. M. Ilyas and B. P. Lamichhane. A stabilised mixed finite element method for the Poisson problem based on a three-field formulation. In Proceedings of the 12th Biennial Engineering Mathematics and Applications Conference, EMAC-2015, volume 57 of ANZIAM J. pages C177–C192, 2016. doi:10.21914/anziamj.v57i0.10356. M. Ilyas and B. P. Lamichhane. A three-field formulation of the Poisson problem with Nitsche approach. In Proceedings of the 13th Biennial Engineering Mathematics and Applications Conference, EMAC-2017, volume 59 of ANZIAM J. pages C128–C142, 2018. doi:10.21914/anziamj.v59i0.12645. B. P. Lamichhane. Two simple finite element methods for Reissner–Mindlin plates with clamped boundary condition. Appl. Numer. Math. 72:91–98, 2013. doi:10.1016/j.apnum.2013.04.005. B. P. Lamichhane and E. P. Stephan. A symmetric mixed finite element method for nearly incompressible elasticity based on biorthogonal systems. Numer. Meth. Part. Diff. Eq. 28(4):1336–1353, 2011. doi:10.1002/num.20683. B. P. Lamichhane, A. T. McBride, and B. D. Reddy. A finite element method for a three-field formulation of linear elasticity based on biorthogonal systems. Comput. Meth. Appl. Mech. Eng. 258:109–117, 2013. doi:10.1016/j.cma.2013.02.008. J. C. Simo and F. Armero. Geometrically non-linear enhanced strain mixed methods and the method of incompatible modes. Int. J. Numer. Meth. Eng. 33(7):1413–1449, may 1992. doi:10.1002/nme.1620330705. A. Zdunek, W. Rachowicz, and T. Eriksson. A five-field finite element formulation for nearly inextensible and nearly incompressible finite hyperelasticity. Comput. Math. Appl. 72(1):25–47, 2016. doi:10.1016/j.camwa.2016.04.022.

Application of Finite Element Methods to Lubrication: An Engineering Approach

1972 ◽  
Vol 94 (4) ◽  
pp. 313-323 ◽  
Author(s):  
J. F. Booker ◽  
K. H. Huebner
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Analysis ◽  
Finite Element Methods ◽  
Lubricant Film ◽  
The Finite Element Method ◽  
Engineering Approach ◽  
Stiffness Method ◽  
Direct Stiffness ◽  
System Properties

The finite element method of lubrication analysis is presented for the novice from a viewpoint closely analogous to that of the familiar direct stiffness method of structural analysis. The lubricant film is seen as a system of component elements interconnected at nodal points where flows are summed and pressures (but not necessarily thicknesses, viscosities, or densities) are equated. System properties are deduced from component properties and connections. Detailed equations needed for solution of practical problems are given in Appendices and their use is illustrated in Examples.

Simulation of tuning graphene plasmonic behaviors by ferroelectric domains for self-driven infrared photodetector applications

Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20868-20875 ◽  
Author(s):  
Junxiong Guo ◽  
Yu Liu ◽  
Yuan Lin ◽  
Yu Tian ◽  
Jinxing Zhang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Interfacial Effect ◽  
Infrared Photodetector ◽  
The Finite Element Method ◽  
Ferroelectric Domains ◽  
Element Method

We propose a graphene plasmonic infrared photodetector tuned by ferroelectric domains and investigate the interfacial effect using the finite element method.

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