• Title/Summary/Keyword: P-element

Search Result 1,970, Processing Time 0.027 seconds

ENHANCING EIGENVALUE APPROXIMATION WITH BANK-WEISER ERROR ESTIMATORS

  • Kim, Kwang-Yeon
    • Korean Journal of Mathematics
    • /
    • v.28 no.3
    • /
    • pp.587-601
    • /
    • 2020
  • In this paper we propose a way of enhancing eigenvalue approximations with the Bank-Weiser error estimators for the P1 and P2 conforming finite element methods of the Laplace eigenvalue problem. It is shown that we can achieve two extra orders of convergence than those of the original eigenvalue approximations when the corresponding eigenfunctions are smooth and the underlying triangulations are strongly regular. Some numerical results are presented to demonstrate the accuracy of the enhanced eigenvalue approximations.

ERROR ESTIMATION FOR NONLINEAR ELLIPTIC PROBLEMS USING THE h-p-MIXED FINITE ELEMENT METHOD IN 3 DIMENSIONAL SPACE

  • Lee, Mi-Young
    • Bulletin of the Korean Mathematical Society
    • /
    • v.38 no.2
    • /
    • pp.237-260
    • /
    • 2001
  • The approximation properties for $L^2$-projection, Raviart-Thomas projection, and inverse inequality have been derived in 3 dimensional space. h-p-mixed finite element methods for strongly nonlinear second order elliptic problems are proposed and analyzed in 3D. Solvability and convergence of the linearized problem have been shown through duality argument and fixed point argument. The analysis is carried out in detail using Raviart-Thomas-Nedelec spaces as an example.

  • PDF

THE RADIAL DERIVATIVES ON WEIGHTED BERGMAN SPACES

  • Kang, Si-Ho;Kim, Ja-Young
    • Communications of the Korean Mathematical Society
    • /
    • v.18 no.2
    • /
    • pp.243-249
    • /
    • 2003
  • We consider weighted Bergman spaces and radial derivatives on the spaces. We also prove that for each element f in B$\^$p, r/ there is a unique f in B$\^$p, r/ such that f is the radial derivative of f and for each f$\in$B$\^$r/(i), f is the radial derivative of some element of B$\^$r/(i) if and only if, lim f(tz)= 0 for all z$\in$H.

A POSTERIORI ERROR ESTIMATOR FOR LINEAR ELASTICITY BASED ON NONSYMMETRIC STRESS TENSOR APPROXIMATION

  • Kim, Kwang-Yeon
    • Journal of the Korean Society for Industrial and Applied Mathematics
    • /
    • v.16 no.1
    • /
    • pp.1-13
    • /
    • 2012
  • In this paper we present an a posteriori error estimator for the stabilized P1 nonconforming finite element method of the linear elasticity problem based on a nonsymmetric H(div)-conforming approximation of the stress tensor in the first-order Raviart-Thomas space. By combining the equilibrated residual method and the hypercircle method, it is shown that the error estimator gives a fully computable upper bound on the actual error. Numerical results are provided to confirm the theory and illustrate the effectiveness of our error estimator.

Advanced Finite Element Technology for Fracture Mechanics Analysis of Cracked Shells (균열 쉘의 파기역학해석을 위한 선진유한요소기법)

  • 우광성
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 1990.10a
    • /
    • pp.3-8
    • /
    • 1990
  • A new finite element technology based on p-version of F.E.M. is discussed with reference to its potential for application to stress intensity factor computations. In linear elastic fracture mechanics, especially cracked cylindrical shells. It is shown that the p-version nutlet is far better suited for computing the stress intensity factors than the conventional h-version models with the help of three test problems. The main advantage of this technology is that the accuracy of approximation can be established without mesh refinement or the use of special procedures.

  • PDF

Response of non-structural components mounted on irregular RC buildings: comparison between FE and EC8 predictions

  • Aldeka, Ayad B.;Chan, Andrew H.C.;Dirar, Samir
    • Earthquakes and Structures
    • /
    • v.6 no.4
    • /
    • pp.351-373
    • /
    • 2014
  • This paper investigates the seismic response of lightweight acceleration-sensitive non-structural components (NSCs) mounted on irregular reinforced concrete (RC) primary structures (P-structures) using non-linear dynamic finite element (FE) analysis. The aim of this paper is to study the influence of NSC to P-structure vibration period ratio, peak ground acceleration, NSC to P-structure height ratio, and P-structure torsional behaviour on the seismic response of the NSCs. Representative constitutive models were used to simulate the behaviour of the RC P-structures. The NSCs were modelled as vertical cantilevers fixed at their bases with masses on the free ends and varying lengths so as to match the frequencies of the P-structures. Full dynamic interaction is considered between the NSCs and P-structures. A set of 21 natural and artificial earthquake records were used to evaluate the seismic response of the NSCs. The numerical results indicate that the behaviour of the NSCs is significantly influenced by the investigated parameters. Comparison between the FE results and Eurocode (EC8) predictions suggests that EC8 underestimates the response of NSCs mounted on the flexible sides of irregular RC P-structures when the fundamental periods and heights of the NSCs match those of the P-structures. The perceived cause of this discrepancy is that EC8 does not take into account the amplification in the dynamic response of NSCs induced by the torsional behaviour of RC P-structures.

Evaluation of Pressure-Temperature Limit Curve for the Safe Operation of an RFV based on 3-D Finite Element Analyses (유한요소해석을 이용한 원자로용기 압력-온도 한계곡선의 평가)

  • Lee, Taek-Jin;Park, Yun-Won;Lee, Jin-Ho;Choe, Jae-Bung;Kim, Yeong-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.25 no.10
    • /
    • pp.1567-1574
    • /
    • 2001
  • In order to operate an RPV safely it is necessary to keep the pressure-temperature (P-T) limit during the heatup and cooldown process. While the ASME Code provides the P-T limit curve for safe operation, this limit curve has been prepared under conservative assumptions In this paper the effects of conservative assumptions involved in the P-T limit curve specified in the ASME Code Sec. XI were investigated. Three different parameters the crack depth the cladding thickness and the cooling rate, were reviewed based on 3-D finite element analyses. Also the constraint effect on P-T limit curve generation was investigated based on J- T approach. It was shown that the crack depth and the constraint effect change the safe region in P-T limit curve significantly Therefore it is recommended to prepare a more precise P-T limit curve based on finite element analysis to obtain P-T limit for safe operation of an RPV.

Study on sound radiation estimation using a reciprocity technique and p-p method by finite element simulation (상반성 기법과 p-p method를 이용한 구조물 방사소음 유한요소해석 기법 연구)

  • Ji Woo Yoo;Hun Park;Ji Un Lee
    • The Journal of the Acoustical Society of Korea
    • /
    • v.42 no.1
    • /
    • pp.1-6
    • /
    • 2023
  • Sound radiated from a structure in vibration is an important physical characteristic to evaluate vibro-acoustic problem. Although sound radiation power can be typically obtained by intensity measurement, long measuring time and strict measuring condition remain difficult. As an alternative method, simulation-based estimation can be taken into account and its accuracy is known to be acceptable. However, difficulty still lies in that specialized softwares may be necessary to obtain sound radiation power and radiation efficiency. In this context, this study suggests two methods using an ordinary FE method to calculate sound radiation power. They are well-known reciprocity technique and p-p method, which are basically test methods. It is shown that either method can practically estimate sound radiation in the frame of conventional Finite Element Method (FEM). The methods and their corresponding limit are discussed with some results.