• Title/Summary/Keyword: Local deformation

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Shape deformation and wear sensation in wearing on support type panty stocking (고탄력 팬티스타킹 착용에 의한 형태변형 및 착용감)

  • 류현혜;성수광
    • Journal of the Ergonomics Society of Korea
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    • v.14 no.1
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    • pp.37-57
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    • 1995
  • The purpose of this study was to investigate the elastic effect of deformation and restriction in wearing a support type panty stocking (PS). The study investigated deformation rate in all surface area, deformation rate in local area, length deformation rate, changes in slip and feeling of restriction under the standard laboratory condition. Two healthy adult females in twenties wore four types of PS. The result were as follows : The deformation rate in all surface area was 117 .approx. 132% in wearing support type PS, 157% in wearing mono type PS, due to the intensities of restriction. The deformation rate in local area was in order, course > oblique > wale direction. The largest deformation rate was observed in hip girth. Between the deformation rates in all surface and local areas was a high correlation acknowledged, especially the course direction showed a high correlation. Support type PSs showed more deformation and changes of slip than wool and mono type PS. Especially, changes of slip at the knee appeared greatly. The responses of restriction evaluated from a paired comparison method were in order, JS 2 > KS 4 > KS 9 > KS 5 > KS 1 > KM 3.

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Deformation and Fracture Behavior of Wall Thinned Carbon Steel Pipes (감육된 탄소강배관의 변형과 파괴거동)

  • Ahn, Seok-Hwan;Nam, Ki-Woo
    • Journal of Ocean Engineering and Technology
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    • v.20 no.4 s.71
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    • pp.17-23
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    • 2006
  • Monotonic four-point bending tests were conducted on straight pipe specimens, 102 mm in diameter with local wall thinning, in order to investigate the effects of the depth, shape, and location of wall thinning on the deformation and failure behavior of pipes. The local wall thinning simulated natural erosion/corrosion metal loss. The deformation and fracture behavior of the straight pipes with local wall thinning was compared with that of non wall-thinning pipes. The failure modes were classifiedas local buckling, ovalization, or crack initiation, depending on the depth, shape, and location of the local wall thinning. Three-dimensional elasto-plastic analyses were carried out using the finite element method. The deformation and failure behavior, simulated by finite element analyses, coincided with the experimental results.

Analysis of Deformation Localization of Void Material using Nolocal Constitutive Relation (I) (비국소형 구성식을 이용한 보이드 재료의 변형 국소화 거동의 해석(I))

  • 김영석;최홍석;임성언
    • Transactions of Materials Processing
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    • v.9 no.1
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    • pp.59-65
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    • 2000
  • Most studies of failure analysis in ductile metals have been based on the classical plasticity theory using the local constitutive relations. These frequently yields a physically unrealistic solution, in which a numerical prediction of the onset of a deformation localization shows an inherent mesh-size sensitivity. A one way to remedy the spurious mesh sensitivity resulted in the unreasonable results is to incorporate the non-local plasticity into the simulation model, which introduce an internal (material) length-scale parameter into the classical constitutive relations. In this paper, a non-local version of the modified Gurson constitutive relation has been introduced into the finite element formulation of the simulation for plane strain compression of the visco elastic-plastic void material. By introducing the non-local constitutive relations we could successfully removed the inherent mesh-size sensitivity for the prediction of the deformation localization. The effects of non-local constitutive relation are discussed in terms of the load-stroke curve and the strain distributions accross the shear band.

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The Effect of Local Basis Weight on Local Strain (지역 평량이 지역 변형률에 미치는 영향)

  • 남원석;백기현
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.31 no.3
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    • pp.105-109
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    • 1999
  • The purpose of this experiment was to see the effect of local basis weight on the local strain during changing moisture content in handsheets. The averaged strain value of the whole size of paper sheet did not give more valuable information to explain non uniform deformation in the paper sheet. The combination of intact strain measurement system KISA (Linear Image Strain Analysis) and local basis weight measurement method using a scanner made it possible to compare local basis weight with local strain to explain moisture induced paper deformation . Usually higher basis weight local area showed higher moisture induced local strain. However, the hygro-induced strain values were highly affected by the behavior of neighbor local areas. Well distributed local basis weight paper would give more uniform local strains than those of non-uniformed local basis weight paper.

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Unique local deformations of the superelastic SMA rods during stress-relaxation tests

  • Ashiqur Rahman, Muhammad;Rahman Khan, Mujibur
    • Structural Engineering and Mechanics
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    • v.22 no.5
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    • pp.563-574
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    • 2006
  • This paper studies mechanical behavior of the superelastic shape memory alloy (SMA) rods in terms of local deformations and time via tensile loading-unloading cycles for both ends fixed end constraints. Besides the unique stress induced martensitic transformation (SIMT), SMA's time dependent behavior when it is in mixed-phase condition upon loading and unloading, also need careful attention with a view of investigating the local deformation of the structural elements made of the same material. With this perspective, the so-called stress-relaxation tests have been performed to demonstrate and investigate the local strains-total strains relationships with time, particularly, during the forward SIMT. Some remarkable phenomena have been observed pertaining to SIMT, which are absent in traditional materials and those unique phenomena have been explained qualitatively. For example, at the stopped loading conditions the two ends (fixed end and moving end of the tensile testing machine) were in fixed positions. So that there was no axial overall deformation of the specimen but some notable increase in the axial local deformation was shown by the extensometer placed at the middle of the SMA specimen. It should be noted that this peculiar behavior termed as 'inertia driven SIMT' occurs only when the loading was stopped at mixed phase condition. Besides this relaxation test for the SMA specimens, the same is performed for the mild steel (MS) specimens under similar test conditions. The MS specimens, however, show no unusual increase of local strains during the stress relaxation tests.

Study on Plastic Deformation of Interior Support at the Continuous I-Beam Bridge (I-Beam연속교 내측지점의 소성변형에 관한 연구)

  • Chung, Kyung-Hee;Kim, Jin-Sung;Yang, Seung-Ie
    • Journal of the Korean Society of Safety
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    • v.17 no.4
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    • pp.146-152
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    • 2002
  • The steel shows plastic deformation after the yield point exceeds. Because of overloads, the plastic deformation occurs at the interior support of a continuous bridge. The plastic deformation is concentrated at the interior support, and the permanence deformation at the interior support remains after loads pass. Because local yielding causes the positive moment at the interior support, it is called "auto moment". Auto moment redistributes the elastic moment. Because of redistribution, auto moment decreases the negative moment at the interior support of a continuous bridge. In this paper, the moment-rotation curve from Schalling is used. The Plastic rotation is computed by using Beam-line method, and auto moment is calculated based on the experiment curve. The design example is presented using limit state criterion.

Haptic Simulation with s-FEM (s-FEM 을 이용한 햅틱 시뮬레이션)

  • Jun, Seong-Ki;Cho, Maeng-Hyo
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.780-785
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    • 2007
  • Accurate and fast haptic simulations of deformable objects are desired in many applications such as medical virtual reality. In haptic interactions with a coarse model, the number of nodes near the haptic interaction region is too few to generate detailed deformation. Thus, local refinement techniques need to be developed. Many approaches have employed purely geometric subdivision schemes, but they are not proper in describing the deformation behavior of deformable objects. This paper presents a continuum mechanics-based finite element adaptive method to perform haptic interaction with a deformable object. This method superimposes a local fine mesh upon a global coarse model, which consists of the entire deformable object. The local mesh and the global mesh are coupled by the s-version finite element method (s-FEM), which is generally used to enhance accurate solutions near the target points even more. The s-FEM can demonstrate a reliable deformation to users in real-time.

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Impact Analysis of a plate structures Employing Hertzian Contact Theory (Hertz 접촉 이론을 이용한 평판 구조물의 충돌 해석)

  • Lim, Hong-Seok;Yoo, Hong-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.04a
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    • pp.383-388
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    • 2008
  • A modeling method for the impact analysis of plate structures employing Hertzian contact theory is presented in this paper. Since local deformation as well as bending deflection of the plate occurs due to the collision, it has to be considered for the impact analysis. When the coefficient of restitution is employed for the impact analysis, the local deformation is not considered. For more accurate and reliable impact analysis, however, the local deformation should be considered. The effects of the location of collision and the collision mass on the impact duration time and the contact force magnitude are investigated through numerical studies employing Hertzian contact theory.

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Haptic Simulation for Deformable Object with s-FEM (s-FEM을 이용한 변형체 햅틱 시뮬레이션)

  • Jun Seong-Ki;Choi Jin-Bok;Cho Maeng-Hyo
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.373-380
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    • 2006
  • Accurate and fast haptic simulations of deformable objects are desired in many applications such as medical virtual reality. In haptic interactions with a coarse model, the number of nodes near the haptic interaction region is too few to generate detailed deformation. Thus, local refinement techniques need to be developed. Many approaches have employed purely geometric subdivision schemes, but they are not proper in describing the deformation behavior of deformable objects. This paper presents a continuum mechanics-based finite element adaptive method to perform haptic interaction 'with a deformable object. This method superimposes a local fine mesh upon a global coarse model, which consists of the entire deformable object. The local mesh and the global mesh are coupled by the s-version finite element method (s-FEM), which is generally used to enhance accurate solutions near the target points even more. The s-FEM can demonstrate a reliable deformation to users in real-time.

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