• Title/Summary/Keyword: FE-simulation

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FINITE ELEMENT ANALYSIS FOR DISCONTINUOUS MAPPED HEXA MESH MODEL WITH IMPROVED MOVING LEAST SQUARES SCHEME

  • Tezuka, Akira;Oishi, Chihiro;Asano, Naoki
    • Proceedings of the Korea Society for Simulation Conference
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    • 2001.10a
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    • pp.373-379
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    • 2001
  • There is a big issue to generate 3D hexahedral finite element (FE) model, since a process to divide the whole domain into several simple-shaped sub-domains is required before generating a continuous mesh with mapped mesh generators. In general, it is nearly impossible to set up proper division numbers interactively to keep mesh connectivity between sub-domains on a complicated arbitrary-shaped domain. If mesh continuity between sub-domains is not required in an analysis, this complicated process can be omitted. Element-free Galerkin method (EFGM) can accept discontinuous meshes, which only requires nodal information. However it is difficult to choose a reasonable influenced domain in moving least squares scheme with non-uniformly distributed nodes in discontinuous FE models. A new FE scheme fur discontinuous mesh is proposed in this paper by applying improved EFGM with some modification to derive FE approximated function in discontinuous parts. Its validity is evaluated on linear elastic problems.

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Analysis of Traumatic Brain Injury Using a Finite Element Model

  • Suh Chang-Min;Kim Sung-Ho;Oh Sang-Yeob
    • Journal of Mechanical Science and Technology
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    • v.19 no.7
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    • pp.1424-1431
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    • 2005
  • In this study, head injury by impact force was evaluated by numerical analysis with 3-dimensional finite element (FE) model. Brain deformation by frontal head impact was analyzed to evaluate traumatic brain injury (TBI). The variations of head acceleration and intra-cranial pressure (ICP) during the impact were analyzed. Relative displacement between the skull and the brain due to head impact was investigated from this simulation. In addition, pathological severity was evaluated according to head injury criterion (HIC) from simulation with FE model. The analytic result of brain damage was accorded with that of the cadaver test performed by Nahum et al.(1977) and many medical reports. The main emphasis of this study is that our FE model was valid to simulate the traumatic brain injury by head impact and the variation of the HIC value was evaluated according to various impact conditions using the FE model.

Comments on a Case Study on Engineering Failure Analysis of Link Chain

  • Yu, George Y.H.
    • Safety and Health at Work
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    • v.12 no.4
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    • pp.544-545
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    • 2021
  • The article by Tae-Gu Kim et al. conducted elastic FE modeling, which was inappropriate for fracture of elastic-plastic chain material (11.3% of elongation). FE analysis results and the findings in the fracto-graphic analysis did not tally but contradicted each other. The article identified "incorrect installation"/bending forces as the root cause while FE results of the chain under bending forces showed very low stresses at fracture locations but the highest stress in the middle of shank of the chain. The article's "step-like topographies indicating the fracture due to bending moment rather than uniaxial tension" lacked scientific support. The load value carried by each chain section under bending/incorrect installation was only half of that under tension, thus the article using same load value in FE simulation comparison for bending and tension was incorrect. The real cause of the chain fracture was likely improper checking the lifted load or/and using the wrong chain with much lower safety working load.

Numerical Investigation of the Progressive Failure Behavior of the Composite Dovetail Specimens under a Tensile Load (인장하중을 받는 복합재료 도브테일 요소의 점진적인 파손해석)

  • Park, Shin-Mu;Noh, Hong-Kyun;Lim, Jae Hyuk;Choi, Yun-Hyuk
    • Composites Research
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    • v.34 no.6
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    • pp.337-344
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    • 2021
  • In this study, the progressive failure behavior of the composite fan blade dovetail element under tensile loading is numerically investigated through finite element(FE) simulation. The accuracy of prediction by FE simulation is verified through tensile testing. The dovetail element is one of the joints for coupling the fan blade with the disk in a turbofan engine. The dovetail element is usually made of a metal material such as titanium, but the application of composite material is being studied for weight reduction reasons. However, manufacturing defects such as drop-off ply and resin pocket inevitably occur in realizing complex shapes of the fan blade made by composite materials. To investigate the effect of these manufacturing defects on the composite fan blade dovetail element, we performed numerical simulation with FE model to compare the prediction of the FE model and the tensile test results. At this time, the cohesive zone model is used to simulate the delamination behavior. Finally, we found that FE simulation results agree with test results when considering thermal residual stress and through-thickness compression enhancement effect.

Development of Side Forming Technology for the Tooth Part Using B.T.Pin in Cold Forming Process (B.T.Pin을 이용한 치형부품의 측면 냉간성형공법 개발)

  • Lee, J.S.;Park, S.J.;Kim, B.M.;Kim, D.H.
    • Transactions of Materials Processing
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    • v.26 no.2
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    • pp.95-100
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    • 2017
  • In this study, the method of process design for side forming of a tooth part used for a component of automobile transmission was suggested using FE-simulations. To develop the side forming for the tooth part, in this paper, the shape factors of B.T.Pin was considered as design parameters. The shape factors of B.T.Pin were selected to be the round of pin, reinforced angle and reinforced length. Based on FE simulation results, appropriate shape factor without causing any defects was selected. In addition, to increase the strength of pin, the combination of shape factor having minimum stress after side forming was selected using FE-simulation. In addition, with design of a die set, cold side forming of the tooth part was experimented to estimate effectiveness of the designed B.T.Pin. From experiments, it was found that the tooth part with complete formation of the tooth was obtained without making any forming defects and punch fracture.

Process Analysis and Die Design for Al3003 Condenser Tube Extrusion with 12 Cell (Al3003 12셀 컨덴서 튜브의 압출을 위한 공정해석 및 금형설계)

  • Lee, Sang-Ho;Lee, Jung-Min;Jo, Hyung-Ho;Jo, Hoon;Kim, Mun-Bae;Kim, Byung-Min
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.11
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    • pp.44-51
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    • 2007
  • Condenser tubes are mainly produced by precision extrusion with a porthole die and are used in the flow pass of refrigerant cooling systems in automobiles. The recent technical trend of condenser tube requires the tube to be of more multi cellizing, high strength and small size, and to increase the heat transfer area and heat efficiency. Hence, this paper is shown that the results of FE-simulation are in good agreement with the experimental ones. Finally, the extrusion die shape is proposed through analysis of FE-simulation and performance of trial extrusion. Chamber shape dimension and initial temperatures of die is adjusted analysis results. And the possibility of extrusion is estimated that forming load, welding pressure and stress analysis of die in this paper. The validity of simulated results was verified into extrusion experiments on the condenser tubes.

Study of Tube Expansion to Produce Hair-Pin Type Heat Exchanger Tubes using the Finite Element Method (유한요소법을 이용한 헤어핀 형 열 교환기의 튜브 확관에 대한 연구)

  • Hong, S.;Hyun, H.;Hwang, J.
    • Transactions of Materials Processing
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    • v.23 no.3
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    • pp.164-170
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    • 2014
  • To predict the deformation and fracture during tube expansion using the finite element (FE) method, a material model is considered that incorporates the damage evolution due to the deformation. In the current study, a Rice-Tracey model was used as the damage model with inclusion of the hydrostatic stress term. Since OFHC Cu is not significantly affected by strain rate, a Hollomon flow stress model was used. The material parameters in each model were obtained by using an optimization method. The objective function was defined as the difference between the experimental measurements and FE simulation results. The parameters were determined by minimizing the objective function. To verify the validity of the FE modeling, cross-verification was conducted through a tube expansion test. The simulation results show reasonable agreement with the experiments. The design for a minimum diameter of expansion tube using the FE modeling was verified by a simplified tube expansion test and simulation results.

Surface Segregation and Order of FeCo Alloy (FeCo 합금의 표면 편석과 질서도)

  • Han, Wone-Keun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.3
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    • pp.240-244
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    • 2010
  • The surface segregation and surface order near the order-disorder phase transition of FeCo alloy was studied through Monte Carlo simulation of an Ising type model Hamiltonian. The results showed that the proper choice of Hamiltonian parameters could reproduce the recent observation of surface order above the transition temperature and that the field term played dominant role.

FE simulation for the Reconstruction of Deceleration Profile in Steel Bar Breaking System (강철봉 제동 시스템에서의 감속파형 재현을 위한 유한 요소 해석)

  • Lee, J.K.;Suk, H.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.05a
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    • pp.213-216
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    • 2008
  • Sled test id widely used to evaluate the performance of occupant's safety system in frontal crash environment without having to conduct a full-scale crash test. Steel bar breaking system is used to generate deceleration profile which is experienced by passengers in frontal crash. In this study, deformation analyses of steel bars were conducted using a commercial FE code. Several guidelines were proposed to improve the accuracy of simulation.

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Evaluation of Optical Performance for an Aspheric Lens Connecting with FE Analysis of Injection Molding (사출성형 유한요소해석과 연계한 비구면렌즈의 광학적 특성평가)

  • Park, K.;Um, H.J.;Kim, J.P.;Joo, W.J.
    • Transactions of Materials Processing
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    • v.16 no.1 s.91
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    • pp.25-30
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    • 2007
  • The present study covers an integrated simulation method to evaluate optical performance of an aspheric plastic lens by connecting a finite element (FE) analysis of injection molding with a ray tracing simulation. Traditional ray tracing methods have based on the assumption that the optical properties of a lens are homogeneous throughout the entire volume. This assumption is to a certain extent unrealistic for injection-molded plastic lenses because material properties vary at every point due to the injection molding effects. To take into account the effects of the inhomogeneous optical properties of the molded lens, a new.ay tracing scheme is proposed in conjunction with a FE analysis of the injection molding. A numerical scheme is developed to calculate ray paths on every element layer with more realistic information of the refractive indices which can be obtained through the FE analysis. This information is then used to calculate the ray paths based on the FE mesh of which nodal points have unique index values. The proposed tracing scheme is implemented on the tracing of an aspheric lens, and its validity is ascertained through experimental verification.