• Title/Summary/Keyword: 경계요소법

Search Result 503, Processing Time 0.152 seconds

Modeling of Elastodynamic Problems in Finite Solid Media (유한 고체내 탄성동역학 문제의 모델링)

  • Cho, Youn-Ho
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.20 no.2
    • /
    • pp.138-149
    • /
    • 2000
  • Various modeling techniques for ultrasonic wave propagation and scattering problems in finite solid media are presented. Elastodynamic boundary value problems in inhomogeneous multi-layered plate-like structures are set up for modal analysis of guided wave propagation and numerically solved to obtain dispersion curves which show propagation characteristics of guided waves. As a powerful modeling tool to overcome such numerical difficulties in wave scattering problems as the geometrical complexity and mode conversion, the Boundary Element Method(BEM) is introduced and is combined with the normal mode expansion technique to develop the hybrid BEM, an efficient technique for modeling multi mode conversion of guided wave scattering problems. Time dependent wave forms are obtained through the inverse Fourier transformation of the numerical solutions in the frequency domain. 3D BEM program development is underway to model more practical ultrasonic wave signals. Some encouraging numerical results have recently been obtained in comparison with the analytical solutions for wave propagation in a bar subjected to time harmonic longitudinal excitation. It is expected that the presented modeling techniques for elastic wave propagation and scattering can be applied to establish quantitative nondestructive evaluation techniques in various ways.

  • PDF

Stress Analysis of the Thin Intersected Axe Gear By 3-DM Boundary Element Methed. (삼차원 경계요소법에 의한 박육직교축 치차의 응력 해석)

  • 장지연
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.14 no.1
    • /
    • pp.72-82
    • /
    • 1990
  • It is impossible to directly analyse stress distribution on thin bevel Gear. On this Paper, the author propose a method to analyse the stress of thin bevel gear boundary element method and develope a computer program. The propriety of this program is verified by comparing the numerical calculating results with theoretical results.

  • PDF

Analysis of stress and stress intensity factor in bonded dissimilar materials by boundary element method (경계요소법을 이용한 이종재료 접착.접합재의 응력 및 응력세기계수 해석)

  • Yi, W.;Chung, N.Y.;Yu, Y.C.;Jeong, E.S.
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.21 no.9
    • /
    • pp.1357-1363
    • /
    • 1997
  • Currently it is increasing to use th bonded dissimilar materials in the various field of advanced engineering such as the highly rigid and lighter vehicle, plastic molding LSI package and metal/ceramic bonded joint. In spite of such a wide application of the bonded dissimilar materials, the evaluation method of the bonding strength has not been established yet. Therefore in this paper we analyze the interface crack problem by introducing fracture mechanics parameters as the basic research about estimating of the strength of adhesive joints. The variation of stress intensity factor according to the elastic modulus of adherend and thickness of bonded layer are investigated. Numerical results are based on the results of boundary element analysis of four different type butt joints subjected to uniaxial tension loading.

Numerical Analysis of Tip Vortex Flow of Three-dimensional Hydrofoil using B-Spline Higher-order Boundary Element Method (B-Spline 고차 경계요소법을 이용한 3차원 수중익의 날개 끝 와류유동 수치해석)

  • Kim, Ji-Hye;Ahn, Byoung-Kwon;Kim, Gun-Do;Lee, Chang-Sup
    • Journal of Ocean Engineering and Technology
    • /
    • v.31 no.3
    • /
    • pp.189-195
    • /
    • 2017
  • A three-dimensional higher order boundary element method based on the B-spline is presented. The method accurately models piecewise continuous bodies and induced velocity potentials using B-spline tensor product representations, and it is capable of obtaining accurate pointwise values for the potential and its derivatives, especially in the trailing edge and tip region of the lift generating body, which may be difficult or impossible to evaluate with constant panel methods. In addition, we implement a wake roll-up and examine the tip vortex formation in the near wake region. The results are compared with existing numerical results and the results of experiments performed out at the cavitation tunnel of Chungnam National University.

An Analysis of Stress Intensity Factors of Composite Materials by Boundary Element Method (BEM) (경계요소법(BEM)에 의한 복합재료의 응력확대계수 해석)

  • 이갑래;조상봉;최용식
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.15 no.1
    • /
    • pp.179-189
    • /
    • 1991
  • Composite materials are generally treated as anisotropic or an orthotropic materials. Unlike isotropic materials, the orthotropic materials can divided three groups depending upon the relationship of the four material constants or depending upon the characteristic roots of orthotropic materials. In particular, the fundamental solutions of two dimensional BEM for composite materials (orthotropic or anisotropic material) generally have a singularity in the conventional method when the characteristic roots are equal. In consideration of this singularity in the conventional method when the characteristic roots are equal. In consideration of this singular problems, in this paper, the fundamental solutions of BEM are systematically analysed for orthotropic materials. And the stress and displacement fields for a crack in an orthotropic materials are singular when the characteristic roots of orthotropic materials are equal. Therefore, these fields for a crack in an orthotropic materials are analysed by the analogous method to isotropic materials when the characteristic roots are equal.