• Title/Summary/Keyword: Finite Element Analysis

Search Result 16,656, Processing Time 0.041 seconds

Evaluation of Efficiency Uncertainty for Three-phase Induction Motor using Finite Element Analysis (유한요소 해석을 이용한 3상 유도전동기의 효율 불확도 평가)

  • Lee, Ho-Hyun;Park, Han-Seok;Jun, Hee-Deuk;Woo, Kyung-Il
    • The Transactions of the Korean Institute of Electrical Engineers P
    • /
    • v.66 no.4
    • /
    • pp.163-168
    • /
    • 2017
  • This paper presented an evaluation method for the efficiency uncertainty of a three-phase induction motor using finite element analysis. The motor efficiency in the finite element analysis is calculated by the loss separation method as in the actual test. In the process of evaluating the efficiency uncertainty, the difference between the finite element analysis and the actual test is the method of calculating the type-A / B standard uncertainty of the input quantity to estimate the efficiency and each losses. For the input quantities which can confirm the instantaneous values with respect to time, the type-A standard uncertainty in the finite element analysis is calculated from the RMS values or average values having separate periods in the steady state. And, the type-B standard uncertainty in the finite element analysis is assumed to be zero. Also, this paper compared and analyzed the efficiency uncertainty evaluated by the proposed method and the efficiency uncertainty through the actual test.

Sensitivity analysis for finite element modeling of humeral bone and cartilage

  • Bola, Ana M.;Ramos, A.;Simoes, J.A
    • Biomaterials and Biomechanics in Bioengineering
    • /
    • v.3 no.2
    • /
    • pp.71-84
    • /
    • 2016
  • The finite element method is wide used in simulation in the biomechanical structures, but a lack of studies concerning finite element mesh quality in biomechanics is a reality. The present study intends to analyze the importance of the mesh quality in the finite element model results from humeral structure. A sensitivity analysis of finite element models (FEM) is presented for the humeral bone and cartilage structures. The geometry of bone and cartilage was acquired from CT scan and geometry reconstructed. The study includes 54 models from same bone geometry, with different mesh densities, constructed with tetrahedral linear elements. A finite element simulation representing the glenohumeral-joint reaction force applied on the humerus during $90^{\circ}$ abduction, with external load as the critical condition. Results from the finite element models suggest a mesh with 1.5 mm, 0.8 mm and 0.6 mm as suitable mesh sizes for cortical bone, trabecular bone and humeral cartilage, respectively. Relatively to the higher minimum principal strains are located at the proximal humerus diaphysis, and its highest value is found at the trabecular bone neck. The present study indicates the minimum mesh size in the finite element analyses in humeral structure. The cortical and trabecular bone, as well as cartilage, may not be correctly represented by meshes of the same size. The strain results presented the critical regions during the $90^{\circ}$ abduction.

Nonlinear finite element analysis of torsional R/C hybrid deep T-beam with opening

  • Lisantono, Ade
    • Computers and Concrete
    • /
    • v.11 no.5
    • /
    • pp.399-410
    • /
    • 2013
  • A nonlinear finite element analysis of R/C hybrid deep T-beam with web opening subjected to pure torsion is presented. Hexahedral 8-nodes and space truss element were used for modeling concrete and reinforcement. The reinforcement was assumed perfectly bonded to the corresponding nodes of the concrete element. The constitutive relations for concrete and reinforcement are based on the modified field theory and elastic perfectly plastic. The smear crack approach was adopted for modeling the crack. The torque-twist angle relationship curve based on the finite element analysis was compared to the experimental results. The comparison shows that the curve of torque-twist angle predicted by the nonlinear finite element analysis is linear before cracking and close to the experimental result. After cracking, the curve becomes nonlinear and stiffer compared to the experimental result.

Sensitivity analysis for optimal design of piezoelectric structures (압전지능구조물의 최적설계를 위한 민감도 해석)

  • 김재환
    • Journal of KSNVE
    • /
    • v.8 no.2
    • /
    • pp.267-273
    • /
    • 1998
  • This study aims at performing sensitivity analysis of piezoelectric smart structure for minimizing radiated noise from the structure, The structure consists of a flat plate on which disk shaped piezoelectric actuator is mounted, and finite element modeling is used for the structure. The finite element modeling uses a combination of three dimensional piezoelectric, flat shell and transition elements so thus it can take into account the coupling effects of the piezoelectric device precisely and it can also reduce the degrees of freedom of the finite element model. Electric potential on the piezoelectric actuator is taken as a design variable and total radiated power of the structure is chosen as an objective function. The objective function can be represented as Rayleigh's integral equation and is a function of normal displacements of the structure. For the convenience of computation, all degrees of freedom of the finite element equation is condensed out except the normal displacements of the structure. To perform the design sensitivity analysis, the derivative of the objective function with respect to the normal displacements is found, and the derivative of the norma displacements with respect to the design variable is calculated from the finite element equation by using so called the adjoint variable method. The analysis results are compared with those of the finite difference method, and shows a good agreement. This sensitivity analysis is faster and more accurate than the finite difference method. Once the sensitivity analysis program is used for gradient-based optimizations, one could achieve a better convergence rate than non-derivative methods for optimal design of piezoelectric smart structures.

  • PDF

Effect of stiffened element and edge stiffener in strength and behaviour of cold formed steel built-up beams

  • Manikandan, P.;Sukumar, S.
    • Advances in Computational Design
    • /
    • v.1 no.2
    • /
    • pp.207-220
    • /
    • 2016
  • The aim of this study is to investigate the effect of stiffened element and edge stiffener in the behaviour and flexural strength of built-up cold-formed steel beams. An experimental and analytical analysis of CFS channel sections in four different geometries is conducted, including simple channel sections, a stiffened channel section with or without edge stiffeners. Nonlinear finite element models are developed using finite element analysis software package ANSYS. The FEA results are verified with the experimental results. Further, the finite element model is used for parametric studies by varying the depth, thickness, and the effect of stiffened element, edge stiffener and their interaction with compression flanges on stiffened built-up cold-formed steel beams with upright edge stiffeners. In addition, the flexural strength predicted by the finite element analysis is compared with the design flexural strength calculated by using the North American Iron and Steel Institute Specifications for cold-formed steel structures (AISI: S100-2007) and suitable suggestion is made.

Multi-stage Finite Element Inverse Analysis of Elliptic Cup Drawing Processes with the Large Aspect Ratio (세장비가 큰 타원형 컵 성형 공정의 다단계 유한요소 역해석)

  • Kim, S.H.;Kim, S.H.;Huh, H.
    • Transactions of Materials Processing
    • /
    • v.9 no.3
    • /
    • pp.304-312
    • /
    • 2000
  • An inverse finite element approach is employed to efficiently design the optimum blank shape and intermediate shapes from the desired final shape in multi-stage elliptic cup drawing processes. The multi-stage deep-drawing process is difficult to design with the conventional finite element analysis since the process is very complicate with the conventional finite element analysis since the process is very complicated with intermediate shapes and the numerical analysis undergoes the convergence problem even with tremendous computing time. The elliptic cup drawing process needs much effort to design sine it requires full three-dimensional analysis. The inverse analysis is able to omit all complicated and tedious analysis procedures for the optimum process design. In this paper, the finite element inverse analysis provides the thickness strain distribution of each intermediate shape through the multi-stage analysis. The multi-stage analysis deals with the convergence among intermediate shapes and the corresponding sliding constraint surfaces that are described by the analytic function of merged-arc type surfaces.

  • PDF

Static Analysis of Two Dimensional Curbed Beam Structure by Finite Element-Transfer Stiffness Coefficent Method (유한요소-전달강성계수법에 의한 2차원 곡선 보 구조물의 정적해석)

  • Choi, Myung-Soo
    • Journal of Power System Engineering
    • /
    • v.21 no.6
    • /
    • pp.40-45
    • /
    • 2017
  • The objective of this study is the finite element-transfer stiffness coefficient method, which is the combination of the modeling technique of finite element method and the transfer technique of transfer stiffness coefficient method, is applied in the static analyses of two dimensional curved beam structures. To confirm the effectiveness of the applied method, two computational models are selected and analyzed by using finite element method, finite element-transfer stiffness coefficient method and exact solution. The computational results of the static analyses for two computational models using finite element-transfer stiffness coefficient method are equal to those using finite element method. When the element partition number of curved beam structure is increased, the computational results of the static analyses using both methods approach the exact solution. We confirmed that the finite element-transfer stiffness coefficient method is superior to finite element method when the number of the curved beam elements is increased from the viewpoints of the computational speed and the utility of computer memory.

Modeling of Progressive Failure in Concrete using Discontinuous Finite Elements (불연속 요소를 사용한 콘크리트 파괴진행의 유한요소 모델링)

  • Shim, Byul;Song, Ha-Won;Byun, Keun-Joo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1996.04a
    • /
    • pp.247-252
    • /
    • 1996
  • In the concrete structures, cracks occur in various causes and the cracks seriously affect the functions of structures. The analysis techniques of progressive crack in the concrete have been improved with the advance of numerical techniques. The discrete crack model used in finite element program for the analysis of progressive failure is very effective, but it can not be easily implemented into numerical procedures because of difficult handing of nodal points in finite element meshes for crack growth. This paper introduces one of the techniques which skips the difficulty. In this paper, the modeling of progressive failure using finite element formulation is explained for the analysis of concrete fracture. The discontinuous element using the discontinuous shape function and the dual mapping technique in the numerical integration are implemented into finite element code for this purpose. It is shown that developed finite element program can predict the quasi-brittle behavior of concrete including ultimate load. The comparisons of the analysis results with other data are also shown.

  • PDF

Finite Element Analysis for Cracks in Rubber Bonded to a Rigid Material (강체와 접합된 고무의 균열에 대한 유한요소해석)

  • 김창식;임세영
    • Computational Structural Engineering
    • /
    • v.7 no.2
    • /
    • pp.111-120
    • /
    • 1994
  • Cracks in rubber bonded to a rigid material such as steel are analyzed with the aid of a mixed finite element technique. Firstly the weak form is derived for finite element analysis of an incompressible material, and the Mooney-Rivlin form is assumed for the constitutive modeling of rubber. The numerical results from finite element analysis is examined to confirm the accuracy and convergence of solution by way of comparison to other numerical results. The interpretation of the J-integral for large elastic deformation as the energy release rate is confirmed, and the J-integral is calculated for varing crack length. The crack growth stability is discussed using the result of finite element analysis.

  • PDF

The evaluation of applicability of spectral element method for the dynamic analysis of the spatial structures (대공간 구조 시스템의 동적 해석을 위한 스펙트럴 요소법의 적용성 평가)

  • Han, Sang-Eul;Lee, Sang-Ju;Cho, Jun-Yeong
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2007.04a
    • /
    • pp.789-794
    • /
    • 2007
  • Recently, the necessity of efficient and exact method to analyze structures is increasing with the importance of the seismic analysis. But the finite element method used in many field do not give the exact solution unless the length of the element is very short enough to represent the deformation of the element. Because the amount of computer calculation increase with the increasing of the number of degree of freedoms, the finite element method for the exact dynamic analysis of structures would not be efficient. To solve these problems, spectral clement method combined spectral method using the principle of wave mechanics and finite element method for the analysis of discrete models is applied to evaluate the behavior of the spatial structures. As a result of analysis. it becomes clear that the spectral element method is faster and more exact than the finite clement method.

  • PDF