• Title/Summary/Keyword: strain plane

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Vibration Characteristics of a Semi-circular Pipe Conveying Fluid with Both Ends Clamped (유체를 이송하는 양단 고정된 반원관의 면내/면외 진동 특성)

  • 정두한;정진태
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.05a
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    • pp.252-257
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    • 2004
  • Free vibration of a semi-circular pipe conveying fluid is analyzed when the pipe is clamped at both ends. To consider the geometric non-linearity, this study adopts the Lagrange strain theory and the extensibility of the pipe. By using the extended Hamilton principle, the non-linear partial differential equations are derived, which are coupled to the in-plane and out-of\ulcornerplant: motions. To investigate the vibration characteristics of the system, the discretized equations of motion are derived from the Galerkin method. The natural frequencies are computed from the linearized equations of motion in the neighborhood of the equilibrium position. From the results. the natural frequencies for the in-plane and out-of-plane motions are vary with the flow velocity. However, no instability occurs the semi-circular pipe with both ends clamped, when taking into account the geometric non-linearity explained by the Lagrange strain theory.

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Failure Mechanism Evaluation in Normally Consolidated Cohesive Soils by Plane Strain Test with Digital Image Analysis (평면변형률 시험에서 디지털 이미지 해석을 통한 정규압밀 점성토의 파괴거동 분석)

  • Kwak, Tae-Young;Kim, Joon-Young;Chung, Choong-Ki
    • Journal of the Korean Geotechnical Society
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    • v.32 no.3
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    • pp.49-60
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    • 2016
  • Soil failure is initiated and preceded by forming and progressing of shear band, defined as the localization of deformation into thin zones of soil mass. To understand the failure mechanism of normally consolidated cohesive soil, the spatial distribution and evolution of deformation within the entire specimen need to be evaluated. In this study, vertical compression tests under plane strain condition were performed on reconstituted kaolinite specimens, while capturing digital images of the specimen at regular intervals during shearing. Overall stress-strain behavior from initial to post peak has been analyzed together with spatial distributions of deformations and shear band characteristics from digital images at 4 stages.

Strain Gradient Crystal Plasticity Finite Element Modeling for the Compression Behaviors of Single Crystals (단결정 압축 변형 거동의 변형구배 결정소성 유한요소해석)

  • Jung, Jae-Ho;Cho, Kyung-Mox;Choi, Yoon Suk
    • Korean Journal of Materials Research
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    • v.27 no.12
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    • pp.679-687
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    • 2017
  • A strain-gradient crystal plasticity finite element method(SGCP-FEM) was utilized to simulate the compressive deformation behaviors of single-slip, (111)[$10{\bar{1}}$], oriented FCC single-crystal micro-pillars with two different slip-plane inclination angles, $36.3^{\circ}$ and $48.7^{\circ}$, and the simulation results were compared with those from conventional crystal plasticity finite element method(CP-FEM) simulations. For the low slip-plane inclination angle, a macroscopic diagonal shear band formed along the primary slip direction in both the CP- and SGCP-FEM simulations. However, this shear deformation was limited in the SGCP-FEM, mainly due to the increased slip resistance caused by local strain gradients, which also resulted in strain hardening in the simulated flow curves. The development of a secondly active slip system was altered in the SGCP-FEM, compared to the CP-FEM, for the low slip-plane inclination angle. The shear deformation controlled by the SGCP-FEM reduced the overall crystal rotation of the micro-pillar and limited the evolution of the primary slip system, even at 10 % compression.

Effects of Pb Aaddition on Microstructur and Texture in High Temperature Plane Strain Compression of Magnesium Alloys (마그네슘 합금의 고온 평면변형 압축에서 Pb 첨가에 따른 미세조직 및 집합조직 변화)

  • Yebeen Ji;Jimin Yun;Kwonhoo Kim
    • Journal of the Korean Society for Heat Treatment
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    • v.37 no.1
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    • pp.23-28
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    • 2024
  • As global warming accelerates, the transportation industry is increasing the use of lightweight materials with the goal of reducing carbon emissions. Magnesium is a suitable material, but its poor formability limits its use, so research is needed to improve it. Rare-earth elements are known to effectively control texture development, but their high cost limits commercial. In this study, changes in microstructure and texture were investigated by adding Pb, which is expected to have a similar effect as rare-earth elements. The material used is Mg-15wt%Pb alloy. Initial specimens were obtained by rolling at 773 K to a rolling reduction of 25% and heat treatment. Afterwards, plane strain compression was performed at 723 K with a strain rate of 5×10-2s-1 and a strain of -0.4 to -1.0. As a result, recrystallized grains were formed within the microstructure, and the main component of the texture changed from (0,0) to (30,26). The maximum axial density was initially 10.01, but decreased to 4.23 after compression.

Restrained Effect of End Plate on Plane Strain Test Evaluated by Digital Image Correlation Method (디지털 이미지 코릴레이션 기법으로 평가한 평면변형률 시험의 단부 구속 효과)

  • Jang, Eui-Ryong;Choo, Yoon-Sik;Lee, Won-Taeg;Chung, Choong-Ki
    • Journal of the Korean Geotechnical Society
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    • v.24 no.7
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    • pp.25-36
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    • 2008
  • The plane strain test can reproduce the real field condition and failure behavior precisely over other laboratory shear tests. Accordingly, this test has been utilized to investigate the shearing behaviors associated with overall failure behavior and local deformation of soils. However, most plane strain tests have been carried out with restrained end plates due to difficulties in manufacturing the equipment and also performing it. This restraint induces different results with real field because of shear stress on end plates. In this study, plane strain tests with/without bottom plate restraint were performed on Jumunjin-sand. The measurement of overall and local deformation was accomplished by digital image correlation technique as well as external LVDT. By applying digital image correlation method using two consecutive images captured through the transparent wall, local deformation behavior of various parts inside the specimen was estimated. And the formation and development of shear band caused by the restrained effect of end plate and the deformation mechanism of sand under plane strain condition were examined.

Characteristics of Walls Supported by Prefabricated Strut (조립식 버팀보로 지지된 흙막이 구조물의 거동 특성에 관한 연구)

  • 김낙경;박종식
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.553-560
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    • 2003
  • From the analytical standpoint, it is advantageous to consider the behavior of supported walls as plane strain condition. But supported walls constitute geotechnical problems which, in strut terms, are not plane strain cases. These represent differences between the measured and the predicted due to the stiffness and spacing of supported walls and the behavior of discontinuous walls such as solider beams with lagging. This study is to investigate simulations of a system behavior along a horizontal section of walls supported by prefabricated strut. Using a beam column method, relative effects associated with prefabricated strut stiffness and spacing in a systematic behavior were investigated.

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An Analysis for Drawing of Strip by UBET with Rigid Elements (강체요소를 이용한 인발 공정의 상계요소 해석)

  • Choi, Il-Kuk;Choi, Young;Hur, Kwan-Do
    • Proceedings of the KSME Conference
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    • 2001.06c
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    • pp.598-603
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    • 2001
  • For metal forming analysis, upper-bound solution is practical method because the solution is overestimated. It is limited to determine stresses on tools by using upper-bound solution. In this study, new scheme to calculate stresses on tools based on upper bound solution is proposed. To verify the proposed scheme, plane strain drawing has been considered. The stresses on tools obtained by the proposed scheme are compared with results of rigid plastic FEM. And the stresses on tools have been determined by the proposed scheme in the forging within plane strain deformation.

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AUTOMOTIVE FORMABILITY SIMULATION PROCESS FOR EARLY DESIGN PHASES

  • EL-SAYED J.;KIM H.;FRUTIGER R.;LIU W.
    • International Journal of Automotive Technology
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    • v.6 no.3
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    • pp.277-283
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    • 2005
  • Formability simulation of automotive panels at early design phases can reduce product and tooling development time and cost. However, for the simulation to be effective in leading the design process, fast and reliable results should be achieved with limited design definition and minimum modeling effort. In this paper, nonlinear finite element analysis is used to develop an automated process for the formability simulation of automotive body panels at early design phases. Due to the limited design definition at early design phases, the automated simulation process is based on the plane strain analysis for selected number of typical sections along the panel. Therefore, an entire panel can be analyzed with few sections. The state of plane strain can be easily induced, during simulation through symmetry and applied boundary conditions that simplify the modeling process. To study the reliability and effectiveness of the developed simulation process, the analytical results are compared with measured results of production automotive body side panels. The comparison demonstrates that the developed simulation process is reliable and can be effective for analyzing sheet metal formability, in early vehicle development phases.

Press Formabilities of Aluminum Sheets for Autobody Application (차체용 알루미늄 판재의 프레스 성형성)

  • Kim, Y.S.;Kim, K.S.;Kwon, N.C.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.1
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    • pp.73-83
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    • 1994
  • Press formabilities of aluminum sheets for automobile body were investigated. Plane strain stretching test (called RIST-PSST), cupping test and U bending test were performed to assess the press formability of aluminum sheets respectively. The results showed that aluminum sheets are generally inferior to cold-rolled steel sheet of deep drawing quality (CSP3N) in press formability. The limiting punch height (LPH) and limiting plane strain (FLCo) of aluminum sheets are 50%-70% level compared to that of CSP3N. Moreover, the limiting drawing ratios(LDR) of aluminum sheets are ranged between 1.95 and 2.1. The poor press formability of aluminum sheets is responsible for low values of total elongation and plastic anisotropy parameter in tensile characteristic. The shape fixability of aluminum sheets evaluated in U bending test is very poor due to its low elastic modulus compared to CSP3N.

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A Predication of Failure in the Stamping Line by Using the Plane Strain Stretch Test (평면 변형 장출 시헙법(PSST)을 이용한 프레스라인에서의 성형 불량 예측)

  • 한수식;박기철;진조관
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.03a
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    • pp.15-18
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    • 1997
  • The plane strain stretch test (PSST) developed by POSCO as an activity of customer service was applied to the establishment of the formability criteria and the prediction of failure during the stamping processes. The PSST was applied to the actual parts such as oil pan and shock mount and the criteria of PSST value for each forming parts were established. These value can provide the possibility of prediction of failure before the stamping process. These results show that the PSST can precisely predict the stamping formability of steel sheets.

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