• Title/Summary/Keyword: J-shape

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Bending characteristics of ISB panel with dimple shapes as inner structures (딤플형 내부 구조체를 가진 ISB 판넬의 굽힘 강성 특성)

  • Ahn D.G.;Lee S.H.;Kim J.S.;Moon G.J.;Han G.Y.;Jung C.J.;Yang D.Y.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.117-118
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    • 2006

  • The objective of this paper is to investigate into bending and failure characteristics of ISB panel with dimple shapes as inner structures. Through three-points bending test, the force-displacement curve and the failure shape are obtained to examine the deformation pattern, characteristic data including maximum load and displacement at the maximum load and failure pattern for the ISB panel. In addition, the influence of design parameters for ISB panel on the bending stiffness and failure mode has been found. From the results of the experiments, it has been shown that bending and failure characteristics of the ISB panel can be controlled by the ratio of radius and the direction of the material.

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Forensic Scientific Analysis for Glass Breakdown Patterns (유리 파손형상의 법과학적 해석)

  • Song, J.Y.;Sa, S.H.;Nam, J.W.;Kim, D.H.;Choi, Y.W.;Kim, J.P.;Goh, J.M.;Park, N.K.
    • Journal of the Korean Society of Safety
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    • v.27 no.3
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    • pp.28-35
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    • 2012

  • We investigated the breakdown patterns of silica glass under the various impacts by forensic scientific analysis. The impacts were chosen by thermal and projectiles impact stress. Thermal impacts under the fire were constructed by changing the position of the flame with gas torches. Physical impacts were constructed with the projectiles of slingshots and rifles by changing the size of the projectiles at the surfaces and the initial distance. Also we identified incident angles of the projectiles by analysis of the punching portion at the glass surface. Under the thermal impacts, the breakdown patterns were various by changing the position of the flame. Especially, the configuration of breakdown patterns had radial shape with the position of the flame at the center of the glass sheet. Under the physical impacts by the projectiles, the breakdown patterns had always radial shape.

  • https://doi.org/10.14346/JKOSOS.2012.27.3.028 인용 PDF KSCI

Relationships Between the Transfemoral Socket Interface Pressure and Myoelectric Signal of Residual Limb During Gait

  • Hong, J.H.;Lee, J.Y.;Chu, J.U.;Lee, J.Y.;Mun, M.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.1070-1073
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    • 2002

  • The biomechanical interaction between the stump and the prosthetic socket is critically important to achieve close-to-normal ambulation. Many investigators suggested that the pressure changes during gait of transfemoral amputees are closely related to the prosthetic alignment, the socket shape, the stump size, and the residual muscle activity. The effects of the prosthetic alignment, the socket shape, and the stump size on the interface pressure were investigated previously. However, there is no report how the residual muscle activities in the transfemoral stump affect the socket interface pressure characteristics during gait. Since designs of socket fur lower limb amputees need to consider the socket interface pressure characteristics, the interface pressure patterns by the residual muscle activities during gait should be investigated. In this study, myoelectric signals (MES) and socket interface pressure in residual limb of transfemoral amputees were measured during the stance and swing phases of gait. For the purpose, specially designed quadrilateral sockets that MES electrodes could be instrumented were fabricated. A total of two transfemoral amputees were participated in the experiments. The measured temporal MES amplitude and interface pressure in knee flexor (biceps femoris) and extensor (rectus femoris) had significant correlations (P ＜ 0.05). Based on the test results, It was suggested that the residual muscle activity of transfemoral amputees stump is an important factor affecting socket pressure changes during walk.

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Shape Design Sensitivity Analysis of Supercavitating Flow Problem (초공동(超空洞) 유동 문제의 형상 설계민감도 해석)

  • Choi, J.H.;Gwak, H.G.;Grandhi, R.
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1047-1052
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    • 2004

  • An efficient boundary-based technique is developed for addressing shape design sensitivity analysis in supercavitating flow problem. An analytical sensitivity formula in the form of a boundary integral is derived based on the continuum formulation for a general functional defined in potential flow problems. The formula, which is expressed in terms of the boundary solutions and shape variation vectors, can be conveniently used for gradient computation in a variety of shape design in potential flow problems. While the sensitivity can be calculated independent of the analysis means, such as the finite element method (FEM) or the boundary element method (BEM), the FEM is used for the analysis in this study because of its popularity and easy-touse features. The advantage of using a boundary-based method is that the shape variation vectors are needed only on the boundary, not over the whole domain. The boundary shape variation vectors are conveniently computed by using finite perturbations of the shape geometry instead of complex analytical differentiation of the geometry functions. The supercavitating flow problem is chosen to illustrate the efficiency of the proposed methodology. Implementation issues for and optimization procedure are addressed in this flow problem.

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