• Title/Summary/Keyword: von Mises 응력

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Thermo-Mechanical Analysis of Though-silicon-via in 3D Packaging (Though-silicon-via를 사용한 3차원 적층 반도체 패키징에서의 열응력에 관한 연구)

  • Hwang, Sung-Hwan;Kim, Byoung-Joon;Jung, Sung-Yup;Lee, Ho-Young;Joo, Young-Chang
    • Journal of the Microelectronics and Packaging Society
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    • v.17 no.1
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    • pp.69-73
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    • 2010
  • Finite-element analyses were conducted to investigate the thermal stress in 3-dimensional stacked wafers package containing through-silicon-via (TSV), which is being widely used for 3-Dimensional integration. With finite element method (FEM), thermal stress was analyzed with the variation of TSV diameter, bonding diameter, pitch and TSV height. It was revealed that the maximum von Mises stresses occurred at the edge of top interface between Cu TSV and Si and the Si to Si bonding site. As TSV diameter increased, the von Mises stress at the edge of TSV increased. As bonding diameter increased, the von Mises stress at Si to Si bonding site increased. As pitch increased, the von Mises stress at Si to Si bonding site increased. The TSV height did not affect the von Mises stress. Therefore, it is expected that smaller Cu TSV diameter and pitch will ensure mechanical reliability because of the smaller chance of plastic deformation and crack initiation.

Analytical Study on Characteristics of von Mises Yield Criterion under Plane Strain Condition (평면변형률상태에서의 von Mises 항복기준의 특성에 관한 이론적 연구)

  • Lee, Seung-Hyun;Kim, Byoung-Il
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.9
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    • pp.6391-6396
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    • 2015
  • In order to investigate characteristics of the von Mises yield criterion under 2 dimensional stress condition, two cases of plane strain were studied. One of which was for zero elastic strain and the other was for zero plastic strain increment. Yield functions for the plane strain condition for zero elastic strain and for the plane stress condition were represented as ellipse and the two yield functions were compared by ratios of major axis, minor axis and eccentricity and it was seen that the ratio of minor axis was the same between the two cases and the ratios of major axis and eccentricity were functions of Poisson's ratio. Region of elastic behavior obtained from considering plane strain condition of zero elastic strain increases as the Poisson's ratio increases. Yield function for plane strain obtained from considering zero plastic increment and associate flow rule was displayed as straight line and the region of elastic behavior was greater than that for the case of plane stress.

Bone Mineral Density and Stress Distribution in Human Patella

  • Han, Seung-Moo;Jared Davis
    • Journal of Biomedical Engineering Research
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    • v.19 no.1
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    • pp.53-58
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    • 1998
  • This study examined the distribution of bone mineral density(BMD) and the von Mises stress in the patella. The BMD of eighteen patellae were determined by using quantitative computed tomography and imaging analysis software. It was found that the BMD of the patella varied with location. BMD values were largest at the superior and lateral regions and decreased inferiorly and medially. This distribution appeared to correspond to the organization of trabeculae within the patella. A two-dimensional finite element analysis was performed on each patella. It was also found that the maximum von Mises stress in the patella occurred along the cortical shell on the non-articular surface. The trabecular von Mises stress existed in the posterior region of the patella. These findings demonstrated the potential for finite element studies in vivo. Further, such studies may lead to the development of custom-made, patient-specific patella prostheses.

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Stress distribution of molars restored with minimal invasive and conventional technique: a 3-D finite element analysis (최소 침습적 충진 및 통상적 인레이 법으로 수복한 대구치의 응력 분포: 3-D 유한 요소 해석)

  • Yang, Sunmi;Kim, Seon-mi;Choi, Namki;Kim, Jae-hwan;Yang, Sung-Pyo;Yang, Hongso
    • Journal of Dental Rehabilitation and Applied Science
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    • v.34 no.4
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    • pp.297-305
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    • 2018
  • Purpose: This study aimed to analyze stress distribution and maximum von Mises stress generated in intracoronal restorations and in tooth structures of mandibular molars with various types of cavity designs and materials. Materials and Methods: Three-dimensional solid models of mandible molar such as O inlay cavity with composite and gold (OR-C, OG-C), MO inlay cavity with composite and gold (MR-C, MG-C), and minimal invasive cavity on occlusal and proximal surfaces (OR-M, MR-M) were designed. To simulate masticatory force, static axial load with total force of 200 N was applied on the tooth at 10 occlusal contact points. A finite element analysis was performed to predict stress distribution generated by occlusal loading. Results: Restorations with minimal cavity design generated significantly lower values of von Mises stress (OR-M model: 26.8 MPa; MR-M model: 72.7 MPa) compared to those with conventional cavity design (341.9 MPa to 397.2 MPa). In tooth structure, magnitudes of maximum von Mises stresses were similar among models with conventional design (372.8 - 412.9 MPa) and models with minimal cavity design (361.1 - 384.4 MPa). Conclusion: Minimal invasive models generated smaller maximum von Mises stresses within restorations. Within the enamel, similar maximum von Mises stresses were observed for models with minimal cavity design and those with conventional design.

Analysis Study on Fatigue Stress on the Orthotropic Steel Deck Applied Polymer Concrete Pavement (폴리머 콘크리트 포장을 적용한 강바닥판의 피로응력에 관한 해석적 연구)

  • Han, Bum-Jin;Yoon, Sang-Il;Choi, Byung-Jin;Choi, Jin-Woong;Park, Sun-Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.5
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    • pp.68-77
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    • 2014
  • In this study, polysulfide epoxy polymer concrete was chosen as an ultra thin bridge deck overlay, and the effect of polymer concrete pavement on the fatigue stress range of the orthotropic steel deck was analyzed through the comparative analysis with epoxy asphalt pavement and SFRC pavement. Abaqus was used to estimate the fatigue stress range, and signed von-mises stress was used to estimate fatigue stress range according to pavement materials and thickness, considering there were multi axis stresses which have longitudinal and lateral direction on the welded parts of the steel deck.

A Simple Calculational Method by using Modified Von Mises Transformation applied to the Coaxial Turbulent Jet Mixing (유동함수를 이용한 난류제트혼합유동 계산에 관한 연구)

  • Choi Dong-Whan
    • Journal of the Korean Society of Propulsion Engineers
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    • v.9 no.2
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    • pp.97-104
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    • 2005
  • A simple but efficient grid generation technique by using the modified compressible form of stream function has been formulated. Transformation of a physical plane to a streamline plane, the Von Mises Transformation, has been widely used to solve the differential equations governing flow phenomena, however, limitation arises in low velocity region of boundary layer, mixing layer and wake region where the relatively large grid spacing is inevitable. Modified Von Mises Transformation with simple mathematical adjustment for the stream function is suggested and applied to solve the confined coaxial turbulent jet mixing with simple $\kappa-\epsilon$ turbulence model. Comparison with several experimental data of axial mean velocity, turbulent kinetic energy, and Reynolds shear stress distribution shows quite good agreement in the mixing layer except in the centerline where the turbulent kinetic energy distributions were somewhat under estimated. This formulation is strongly suggested to be utilized specially for free turbulent mixing layers in axisymmetric flow conditions such as the investigation of mixing behavior, jet noise production and reduction for Turbofan engines.

Safety Evaluation of Horizontal and Vertical Bolted Connection between PHC Piles Using Finite Element Analysis (유한요소해석을 통한 수평 및 수직볼트로 체결된 PHC 파일 연결부의 안전성 평가)

  • Kim, Su Eun;Kim, Sung Bo
    • Journal of Korean Society of Steel Construction
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    • v.30 no.2
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    • pp.97-104
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    • 2018
  • The safety evaluation of horizontal and vertical bolted connection between PHC piles is presented. The numerical analysis model is constructed using the commercial finite element program, ABAQUS, in which 3D solid element is used to model all the connection devices. The actual bolted connection is idealized by the contact and tie condition given in ABAQUS. Through the finite element analysis, the compression, tensile, bending and shear behaviors of PHC pile connection were analyzed. The safety factor based on Von-Mises and yield stress was calculated for the safety evaluation of each connection devices.

Finite Element Analysis on the Stress and Displacement Characteristics of Oil Pipe (오일 파이프의 응력 및 변형거동특성에 관한 유한요소해석)

  • Kim, Chung-Kyun;Cho, Seung-Hyun
    • Tribology and Lubricants
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    • v.25 no.6
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    • pp.374-380
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    • 2009
  • This paper presents the stress and displacement characteristics of oil pipe using the finite element analysis. Displacement in axial direction and von Mises stress of a pipe were analyzed with three design factors, which are the pipe thickness, the corrugation pitch and the corrugation height, under uniform oil pressure. The FE computed results are presented between a conventional round pipe and a rectangular pipe, which is manufactured in this study. The computed FE results show that maximum displacement in axial direction and von Mises stress of pipe are increased linearly as the oil pressure increases. Also, they are increased linearly as the corrugation pitch, corrugation height and pipe thickness increases. von Mises stress of a rectangular pipe at the edge increases sharply compared with that of a conventional round pipe. Therefore, the strength of rectangular pipe is superior to that of a conventional round pipe.

Stress and Modal Analysis for the Rotor System of a Medical Centrifuge using Finite Element Method (유한요소법을 이용한 의료용 원심분리기 로터의 응력 및 고유치 해석)

  • Kim, Sung-Min;Yang, In-Chul;Kim, Do-Gyoon;Kim, Hak-Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.6
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    • pp.78-85
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    • 2007
  • In this study, we performed finite element analysis for the design of a medical centrifuge and two-types of centrifuge were compared with each other. The types of centrifuge are 2-arm straight type and 3-arm type. Structural analysis was done with respect to the change of the rotational speed of the rotor of a centrifuge. When the rotor of centrifuge was rotated, the von Mises stress of 2-arm straight type-rotor was compared with the von Mises stress of 3-arm type. The margin of safety was estimated from the result. We found the critical speed of centrifuge from the campbell diagram by modal analysis.

THE EFFECT OF RESTORATIVE MATERIALS ON THE STRESS DISTRIBUTION OF CLASS V COMPOSITE RESIN RESTORATIONS - A 3D FINITE ELEMENT INVESTIGATION (수복재료가 5급 복합레진 수복물의 응력분포에 미치는 영향에 관한 3차원유한요소법적 연구)

  • Ahn, Hyoung-Ryoul;Kim, Hyeon-Cheol;Hur, Bock;Park, Jeong-Kil
    • Restorative Dentistry and Endodontics
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    • v.31 no.1
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    • pp.20-29
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    • 2006
  • The purpose of this study was to analyze the stress distribution aspect of unrestored and restored combined shape (wedge shape occulusally and saucer shape gingivally) class V cavity, which found frequently in clinical cases. A maxillary second permolar restored with a combined shape class V composite restorations were modeled using the three dimensional finite element method. Static occlusal load of 170 N was applied on lingual incline of buccal cusp at the angle of $45^{\circ}$ with the longitudinal axis of the tooth. And three dimensional finite element analysis was taken by ANSYS (Version 6.0, Swanson Analysis System Co., Houston, U.S.A) program which represent the stress distribution on unrestored and restored cavity wall and margin. The conclusions were as follows. 1. Compared to the unrestored cavity, Von Mises stress at the cementoenamel junction and line angle of the cavity base were reduced and in restored cavity. 2. Von Mises stress at the occlusal and cervical cavity margin and wall were increased in restored cavity in comparison with the unrestored cavity. 3. In the hybrid and hybrid/flowable composite resin restoration, Von Mises stress at the cementoenamel junction and line angle of the cavity base were reduced more than in the flowable restoration. 4. In the hybrid and hybrid/flowable composite resin restoration, Von Mises stress at the occlusal and cervical cavity margin and wall were increased more than in the flowable restoration.