• Title/Summary/Keyword: regridding method

Search Result 3, Processing Time 0.015 seconds

A Study on the Optimal Shape Design Using Automatic Regridding and Design Element (자동 격자 생성법과 설계 요소를 이용한 형상 최적 설계에 관한 연구)

  • Kim, Ho-Ryong;Dan, Byung-Ju
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.10 no.3
    • /
    • pp.87-96
    • /
    • 1993
  • In this study, the peak stress of a fuillet in elastic structure was optimized to have minimum value by using quadratic isoparametric element. The method of auomatic gridding was also developed along with shape algorithm and design element technique was adopted in selecting design variables. The computer program developed was combined with the Hooke-Jeeves direct algorithm of optimization techniques in order to minimize the peak stress of the fillet. The imployment of design element technique significantly cut down computer time by the reduction in design variables, and the opitmum fillet shape with uniform minimum stress was obtained by varying design variables along x and y directions in improving the shape compared to other results. By using automatic gridding, in which Bezier surfaces and Coons surfaces of cubic interpolation were employed, the irregular boundary was removed resulting in smoother anbd more accurate fillet shape possessing uniform minimum stress.

  • PDF

Shape Optimum Design of Cantilever with Weight and Journal Bearing Cap (자중을 고려한 외팔보와 저널 베어링 덮개의 형상 최적설계)

  • Lim, O-Kang;Lee, Jin-Suk;Cho, Heon;Lee, Byung-Woo
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.12 no.3
    • /
    • pp.427-435
    • /
    • 1999
  • In the field of shape optimum design, much efforts are needed in regridding method and shape design sensitivity analysis. In this paper, Bezier curve is used to make the boundary of a structure and the improved direct differentiation method is used to calculate the shape design sensitivity. To regrid the finite element model, modified displacement field is presented in this paper. The modified displacement field makes more fine grid at large curvature. The purpose of this paper is to obtain the optimum shape of a cantilever with weight and a 3-dimensional journal bearing cap.

  • PDF

Quantification of nonlinear seismic response of rectangular liquid tank

  • Nayak, Santosh Kumar;Biswal, Kishore Chandra
    • Structural Engineering and Mechanics
    • /
    • v.47 no.5
    • /
    • pp.599-622
    • /
    • 2013
  • Seismic response of two dimensional liquid tanks is numerically simulated using fully nonlinear velocity potential theory. Galerkin-weighted-residual based finite element method is used for solving the governing Laplace equation with fully nonlinear free surface boundary conditions and also for velocity recovery. Based on mixed Eulerian-Lagrangian (MEL) method, fourth order explicit Runge-Kutta scheme is used for time integration of free surface boundary conditions. A cubic-spline fitted regridding technique is used at every time step to eliminate possible numerical instabilities on account of Lagrangian node induced mesh distortion. An artificial surface damping term is used which mimics the viscosity induced damping and brings in numerical stability. Four earthquake motions have been suitably selected to study the effect of frequency content on the dynamic response of tank-liquid system. The nonlinear seismic response vis-a-vis linear response of rectangular liquid tank has been studied. The impulsive and convective components of hydrodynamic forces, e.g., base shear, overturning base moment and pressure distribution on tank-wall are quantified. It is observed that the convective response of tank-liquid system is very much sensitive to the frequency content of the ground motion. Such sensitivity is more pronounced in shallow tanks.