• Title, Summary, Keyword: Hybrid Finite Element Method

Search Result 307, Processing Time 0.037 seconds

HYBRID POWER FLOW ANALYSIS USING SEA PARAMETERS

  • Park, Y.H.;Hong, S.Y.
    • International Journal of Automotive Technology
    • /
    • v.7 no.4
    • /
    • pp.423-439
    • /
    • 2006
  • This paper proposes a hybrid analytic method for the prediction of vibrational and acoustic responses of reverberant system in the medium-to-high frequency ranges by using the PFA(Power Flow Analysis) algorithm and SEA(Statistical Energy Analysis) coupling concepts. The main part of this method is the application of the coupling loss factor(CLF) of SEA to the boundary condition of PFA in reverberant system. The hybrid method developed shows much more promising results than the conventional SEA and equivalent results to the classical PFA for various damping loss factors in a wide range of frequencies. Additionally, this paper presents applied results of hybrid power flow finite element method(hybrid PFFEM) by formulating the new joint element matrix with CLF to analyze the vibrational responses of built-up structures. Finally, the analytic results of coupled plate structures and an automobile-shaped structure using hybrid PFFEM were predicted successively.

Analytical Study on Hybrid Prefabricated Retrofit Method for Reinforced Concrete Beams (철근 콘크리트 보의 보강을 위한 하이브리드 조립형 보강기법에 관한 해석적 연구)

  • Moon, Sang-Pil;Lee, Sung-Ho;Lee, Young-Hak;Kim, Min-Sook
    • Journal of Korean Association for Spatial Structures
    • /
    • v.20 no.3
    • /
    • pp.71-79
    • /
    • 2020
  • In this paper, the hybrid prefabricated retrofit method that improve structural performance and reduce construction period was developed by using a finite element analysis. The hybrid prefabricated retrofit method consist of a Z-shaped side plate, a L-shaped lower plate, and a bottom plate containing an steel plate with openings. This shape has advantage that a retrofit method is possible regardless of the size of the beams and a follow-up process such as reinforcement bars placing are not required. The finite element analysis of hybrid Prefabricated retrofit method showed the most ideal stress distribution when the thickness of bottom plate was 10mm, the thickness of the L-shaped lower plate was 5mm, the thickness of the Z-shaped side plate was 2.5mm, and the bolt spacing was 200mm. The bending strength equation of Hybrid prefabricated retrofit method was proposed through the plastic stress distribution method in KDS 41 31 00. The result of Comparison the proposed equation with the finite element analysis, it is determined that the design of hybrid prefabricated retrofit method is possible through the KDS 41 31 00.

Spring-Back Prediction for Sheet Metal Forming Process Using Hybrid Membrane/shell Method (하이브리드 박막/쉘 방법을 이용한 박판성형공정의 스프링백 해석)

  • 윤정환;정관수;양동열
    • Transactions of Materials Processing
    • /
    • v.12 no.1
    • /
    • pp.49-59
    • /
    • 2003
  • To reduce the cost of finite element analyses for sheet forming, a 3D hybrid membrane/shell method has been developed to study the springback of anisotropic sheet metals. In the hybrid method, the bending strains and stresses were analytically calculated as post-processing, using incremental shapes of the sheet obtained previously from the membrane finite element analysis. To calculate springback, a shell finite element model was used to unload the final shape of the sheet obtained from the membrane code and the stresses and strains that were calculated analytically. For verification, the hybrid method was applied to predict the springback of a 2036-T4 aluminum square blank formed into a cylindrical cup. The springback predictions obtained with the hybrid method was in good agreement with results obtained using a full shell model to simulate both loading and unloading and the experimentally measured data. The CPU time saving with the hybrid method, over the full shell model, was 75% for the punch stretching problem.

High Performance Hybrid Direct-Iterative Solution Method for Large Scale Structural Analysis Problems

  • Kim, Min-Ki;Kim, Seung-Jo
    • International Journal of Aeronautical and Space Sciences
    • /
    • v.9 no.2
    • /
    • pp.79-86
    • /
    • 2008
  • High performance direct-iterative hybrid linear solver for large scale finite element problem is developed. Direct solution method is robust but difficult to parallelize, whereas iterative solution method is opposite for direct method. Therefore, combining two solution methods is desired to get both high performance parallel efficiency and numerical robustness for large scale structural analysis problems. Hybrid method mentioned in this paper is based on FETI-DP (Finite Element Tearing and Interconnecting-Dual Primal method) which has good parallel scalability and efficiency. It is suitable for fourth and second order finite element elliptic problems including structural analysis problems. We are using the hybrid concept of theses two solution method categories, combining the multifrontal solver into FETI-DP based iterative solver. Hybrid solver is implemented for our general structural analysis code, IPSAP.

Effect of element size in hybrid stress analysis around a hole in loaded orthotropic composites (직교이방성 재료의 구멍주위에 관한 하이브리드 응력해석시 요소크기의 효과)

  • Baek, Tae-Hyun
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.21 no.10
    • /
    • pp.1702-1711
    • /
    • 1997
  • A numerical study for the number of terms of a power series stress function and the effect of hybrid element size on stress analysis around a hole in loaded orthotropic composites is presented. The hybrid method coupling experimental and/or theoretical inputs and complex variable formulations involving conformal mappings and analytical continuity is used to calculate tangential stress on the boundary of the hole in uniaxially loaded, finite width glass epoxy tensile plate. The tests are done by rarying the number of terms, element size and nodal locations on the external boundary of the hybrid region. The numerical results indicate that the hybrid method is accurate and powerful in both experimental and numerical stress analysis.

A numerical solution for a finite internally cracked plate using hybrid crack element method

  • Chen, Y.Z.
    • Structural Engineering and Mechanics
    • /
    • v.40 no.6
    • /
    • pp.813-827
    • /
    • 2011
  • This paper provides a numerical solution for a finite internally cracked plate using hybrid crack element method (HCE). In the formulation, an inclined crack is placed in any place of a rectangular element and the complex variable method is used. The complex potentials are expressed in a series form, and several undetermined coefficients are involved. The complex potentials for the cracked rectangle are first suggested in this paper. Based on a variational principle, the element stiffness matrix can be evaluated. The next steps are same as in the usual finite element method. Several numerical examples with computed stress intensity factor and T-stress are presented.

Efficient geometric nonlinear analyses of circular plate bending problems

  • Duan, Mei
    • Structural Engineering and Mechanics
    • /
    • v.20 no.4
    • /
    • pp.405-420
    • /
    • 2005
  • In this paper, a hybrid/mixed nonlinear shell element is developed in polar coordinate system based on Hellinger/Reissner variational principle and the large-deflection theory of plate. A numerical solution scheme is formulated using the hybrid/mixed finite element method (HMFEM), in which the nodal values of bending moments and the deflection are the unknown discrete parameters. Stability of the present element is studied. The large-deflection analyses are performed for simple supported and clamped circular plates under uniformly distributed and concentrated loads using HMFEM and the traditional displacement finite element method. A parametric study is also conducted in the research. The accuracy of the shell element is investigated using numerical computations. Comparisons of numerical solutions are made with theoretical results, finite element analysis and the available numerical results. Excellent agreements are shown.

Formulation Method of a Singular Finite Element for Orthotropic Materials and its Application (직교 이방성 특이 유한요소의 구성과 그 응용)

  • Lee, Wan-Keun;Lim, Jang-Keun
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.464-469
    • /
    • 2000
  • In order to analyze effectively the discontinuous parts such as holes or notches included in mechanical structures by the finite element method, a singular finite element for orthotropic materials. is proposed. This singular element is formulated by the Trefftz method and the hybrid variational principles, which the displacements and stresses are simultaneously assumed using the Trefftz functions. Through several numerical tests, it is shown that the proposed singular element is very efficient for the accurate stress analysis of the various types of discontinuous parts.

  • PDF

Fracture Analysis of Spot-Welds with Edge Cracks using 2-D Hybrid Special Finite Element (이차원 하이브리드 요소를 이용한 균열을 내포하는 용접점의 유한요소 파단해석)

  • Song J. H.;Yang C. H.;Huh H.;Kim H. G.;Park S. H.
    • Transactions of Materials Processing
    • /
    • v.13 no.6
    • /
    • pp.484-489
    • /
    • 2004
  • This paper employed a systematic analysis using a 2-D hybrid special finite element containing an edge crack in order to describe the fracture behavior of spot-welds in automotive structures. The 2-D hybrid special finite element is derived form a mixed formulation with a complex potential function with the description of the singularity of a stress field. The hybrid special finite element containing an edge crack can give a better description of its singularity with only one hybrid element surrounding one crack. The advantage of this special element is that it can greatly simplify the numerical modeling of the spot welds. Some numerical examples demonstrate the validity and versatility of the present analysis method. The lap-shear, lap-tension and angle-clip specimens are analyzed and some useful fracture parameters such as the stress intensity factor and the initial direction of crack growth are obtained simultaneously.

Fracture analysis of spot-welds with an edge crack using 2-D hybrid special finite element (이차원 하이브리드 특별 요소을 이용한 균열을 내포하는 용접점의 파단 해석)

  • Yang C. H.;Song J. H.;Huh H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • /
    • pp.39-42
    • /
    • 2004
  • In the present paper, a novel systematic method using the 2-D hybrid special finite elements containing an edge crack is employed to study the fracture behaviors of laser beam spot-welds in automotive structures. 2-D hybrid special finite elements each containing an edge crack can assure the high precision especially in the vicinity of crack tips and give a better description of its singularity with only one hybrid element surrounding one crack. Therefore, the numerical modeling of the laser beam spot-welds can be greatly simplified. Some numerical examples are provided to demonstrate the validity and versatility of the proposed method. All the lap-shear, lap-tension and angle clip specimens are analyzed and some useful fracture parameters (such as stress intensity factors, the initial direction of crack growth) are obtained simultaneously.

  • PDF