• Title, Summary, Keyword: FEM

Search Result 6,815, Processing Time 0.057 seconds

FEM simulations of load cell weighing sensor (Load cell 중량센서의 FEM simulation)

  • 박찬원
    • Electrical & Electronic Materials
    • /
    • v.7 no.3
    • /
    • pp.200-205
    • /
    • 1994
  • The FEM technique was applied to simulate the change of stress characteristics for various structural parameters and loading positions of the load cell. The output voltage of the load cell was then computed to compare with the manufactured load cell. The tendency of the stress variations of the load cell was well agreed with the basic formula of the single fixed. beam. Also, the stress characteristics according to the change of loading positions showed respective featured results as different structure. The calculated output voltages of the load cell were very close to those of the real manufactured ones.

  • PDF

Implementation of Q-Tensor Model into 3-D Finite Element Method (FEM) Numerical Solver

  • Shin, Woo-Jung;Yoon, Hyung-Jin;Won, Tae-Young
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • /
    • pp.509-512
    • /
    • 2007
  • In this paper, we report our successful implementation of Q tensor model in threedimensional finite element method (FEM) simulator. The 3D-FEM Q tensor-model-based simulation revealed that the spaly-to-bend transition occurs only at 4 V while the vector-model based FEM solver provides an erroneous transition voltage of 8 V.

  • PDF

The Application of a Direct Coupled BEM-FEM Model to Predict the TL Characteristics of Simple Expansion Silencers with Vibratory Walls (진동 벽면을 가진 단순 확장형 소음기 모델의 투과손실 특성 해석을 위한 DIRECT BEM-FEM 연성 모델의 적용)

  • Choi, C.H.;Kim, H.Y.
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.6 no.6
    • /
    • pp.24-30
    • /
    • 1998
  • A directly coupled Boundary Element and Finite Element Model was applied to the dynamic analysis of a coupled acoustic silencer with vibratory wall. In this cupled BEM-FEM muffler model, the BEM model was used to discretize the acoustic cavity and the FEM model was used to discretize the vibratory wall structure. Then the BEM model was coupled with the FEM model. The results of the coupled BEM-FEM model for the dynamic analysis of the simple expansion type reactive muffler configurations with flexible walls were verified by comparing the predicted results to analytical solutions. In order to investigate the effects of the muffler's structural flexibility on its transmission loss(TL) characteristics, the results of the coupled BEM-FEM model in conjunction with the four-pole parameter theory were utilized. The muffler's TL characteristics using the BEM-FEM coupled model with flexible walls as compared to other muffler configurations was studied. Finally the muffler's TL values with respect to different wall's thickness are predicted and compared.

  • PDF

Satellite FEM Validation test for High Frequency Jitter Analysis

  • Oh, Shi-Hwan;Yong, Ki-Lyuk
    • Bulletin of the Korean Space Science Society
    • /
    • /
    • pp.28.4-29
    • /
    • 2008
  • The aim of the test is to provide an experimental basis to validate the prediction of the FEM for high frequency jitter analysis due to reaction wheel. The principle is to measure structural transfer functions between the input disturbances at RWA base plate and the accelerations near the end tips of payload, in a configuration close to the operational model. The spacecraft shall have to be suspended, in order to be representative of on-orbit boundary conditions. The results of the test shall be compared to the output of the FEM analysis, and if needed, local upgrades of the FEM and/or margin policy shall be defined in order to guarantee a good test/FEM consistency. Test results were compared with the transfer functions of the FEM, which is globally tuned based on the results of vibration test and consequently have lower damping coefficients values than 1% in the frequency range of 60~200Hz. The damping coefficients estimated from the figures of FRF test results are different from the theoretical FEM, but the magnitude trend of FRF of the test results is somewhat similar with the analytical, it is expected that the overall jitter effect of final estimation is nearly same with the preliminary analysis result in which the damping coefficients were assumed to be 1% for all modes in FEM.

  • PDF

Repair LCC Evaluation of RC Structures through the FEM Analysis of Chloride Ion Penetration (염소이온 침투 FEM 해석을 통한 RC구조물의 보수 LCC 평가)

  • Lee, Han-Seung
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.10 no.1
    • /
    • pp.223-230
    • /
    • 2006
  • In this paper the method for repair LCC evaluation of reinforced concrete structures deteriorated by chloride attack was constructed. Also, the FEM analysis for chloride ion penetration into concrete was conducted to evaluate the repair LCC which was decided by the number of repair times including early stages of construction and repair construction during the service life of structures. As a result, the number of repair times is obtained from the comparing the concentration of the chloride ion in a rebar position, and the critical chloride ion concentration of rebar corrosion through the FEM analysis considering the kind of repair materials and methods. Also, the repair LCC could be calculated by the number of repair times during the service life of structures.

Structural health rating (SHR)-oriented 3D multi-scale finite element modeling and analysis of Stonecutters Bridge

  • Li, X.F.;Ni, Y.Q.;Wong, K.Y.;Chan, K.W.Y.
    • Smart Structures and Systems
    • /
    • v.15 no.1
    • /
    • pp.99-117
    • /
    • 2015
  • The Stonecutters Bridge (SCB) in Hong Kong is the third-longest cable-stayed bridge in the world with a main span stretching 1,018 m between two 298 m high single-leg tapering composite towers. A Wind and Structural Health Monitoring System (WASHMS) is being implemented on SCB by the Highways Department of The Hong Kong SAR Government, and the SCB-WASHMS is composed of more than 1,300 sensors in 15 types. In order to establish a linkage between structural health monitoring and maintenance management, a Structural Health Rating System (SHRS) with relevant rating tools and indices is devised. On the basis of a 3D space frame finite element model (FEM) of SCB and model updating, this paper presents the development of an SHR-oriented 3D multi-scale FEM for the purpose of load-resistance analysis and damage evaluation in structural element level, including modeling, refinement and validation of the multi-scale FEM. The refined 3D structural segments at deck and towers are established in critical segment positions corresponding to maximum cable forces. The components in the critical segment region are modeled as a full 3D FEM and fitted into the 3D space frame FEM. The boundary conditions between beam and shell elements are performed conforming to equivalent stiffness, effective mass and compatibility of deformation. The 3D multi-scale FEM is verified by the in-situ measured dynamic characteristics and static response. A good agreement between the FEM and measurement results indicates that the 3D multi-scale FEM is precise and efficient for WASHMS and SHRS of SCB. In addition, stress distribution and concentration of the critical segments in the 3D multi-scale FEM under temperature loads, static wind loads and equivalent seismic loads are investigated. Stress concentration elements under equivalent seismic loads exist in the anchor zone in steel/concrete beam and the anchor plate edge in steel anchor box of the towers.

On the Critical Tension Force and Analysis by the FEM for Puckering in the Cylindrical Cup-Drawing (원통드로잉 성형에 있어서 Puckering 억제조건과 FEM-Simulation 해석)

  • 후등학;임철록;정태훈
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • /
    • pp.80-94
    • /
    • 1994
  • As for axisymmetirc sheet metal forming, a kind of pick-up apparatus for body-wrinkling is deviced. Experiments with both hemispherical and flat headed punches, with various clearances between punch and die, with respect to three kinds of materials each of which has two thicknesses, are performed. Firstly the process of evolution of body-wrinkling is observed. Then the critical blank-holding force (or meridional tensile force) for suppression of body-wrinkling at a specified punch-stroke is measured for all cases mentioned above. An empirical formula for it is proposed. Deformation patterns and stress distributions are analysed by the use of FEM. A simplified critical condition for body-wrinkling is formulated and introduced into the FEM program. And its effectiveness is checked by comparison with the experimental results. Using this FEM system, the governing factors of body-wrinkling are cleared up.

  • PDF

A Study on FEM Application in PIC Plasma Simulation (PIC 플라즈마 시뮬레이션에서의 유한요소법 적용에 관한 연구)

  • Min, Woong-Kee;Kim, Hyeong-Seok;Lee, Seok-Hyun;Hahn, Song-Yop
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.163-165
    • /
    • 1996
  • In the PIC simulation of plasma, the fields are commonly calculated on uniform spatial grids using FDM. But, FDM has a difficulty in modeling a complex shaped model. FEM has a good flexibiblity in treating a complex shape, so that we calculated the field by using FEM not FDM. In this paper, the plasma between plane-to-plane electrodes was simulated using FEM and FDM. Comparing the results of those two methods told us that FEM is also valid as a calculating method in PIC plasma simulation. In order to verify the use of FEM, the discharge of rod-to-plane was simulated. There was not a little distortion of the electric field between the electrodes due to the distribution of space charges.

  • PDF

A Study on the Thermal Specific of Operational Spindle System of Machine Tool by FEM (주축의 동적거동시 FEM을 이용한 열적 특성에 관한연구.)

  • 임영철;김종관
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • /
    • pp.396-400
    • /
    • 2003
  • This paper has studied thermal characteristics of machine tool to develope high speed spindle and optimum design condidering the thermal deformation. Comparing the test data of temperature measurement and structural analysis data using FEM, we verifiedthe test validity and predicted thermal deformation, influence of spindle generation of heat, and established cooling system to prevent the thermal deformation. 1) The temperature rise of spindle system depends on increasing number of rotation and shows sudden doubling increment of number of rotation over 7,000rpm. 2) Oil jacket cooling can be effective cooling method below 8,000rpm but, over 8,000rpm, it shows the decrement of cooling effect. 3) Comparing FEM analysis results and revolution test results, we can confirmn approximate temperature change consequently, it is possible to simulate temperature rise and thermal distribution on the inside of spindle system. 4) We can confirm that simulated approach by FEM analysis can be effective method in thermal-appropriate design..

  • PDF