• Title/Summary/Keyword: Elastic Area

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Immediate Effect of Elastic Taping on Postural Sway in Patients with Stroke

  • Cho, Kyun Hee;Park, Shin Jun
    • Journal of International Academy of Physical Therapy Research
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    • v.9 no.4
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    • pp.1631-1635
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    • 2018
  • Stroke can cause leg weakness, sensory abnormalities, and balance disorders. The purpose of this study was to investigate the effect of elastic taping on postural sway in patients with stroke. This study randomly applied elastic taping to 20 patients with stroke in two ways. The center of pressure (COP) distribution was measured before and after the elastic taping. The measurement variables were COP area and length, and measurements were performed immediately after taping. The elastic taping on tibialis anterior muscle showed a significant decrease in COP area and length compared to that without elastic taping. The elastic taping on gastrocnemius muscles showed a significant decrease in COP area and length compared to that without elastic taping. There was no significant difference in COP area and length between the elastic taping on tibialis anterior muscle and gastrocnemius muscles. Our results suggested that applying elastic taping on the ankle joints is effective in decreasing postural sway after in patients with stroke.

Elastic local buckling behaviour of corroded cold-formed steel columns

  • Nie Biao;Xu Shanhua;Hu WeiCheng;Chen HuaPeng;Li AnBang;Zhang ZongXing
    • Steel and Composite Structures
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    • v.48 no.1
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    • pp.27-41
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    • 2023
  • Under the long-term effect of corrosive environment, many cold-formed steel (CFS) structures have serious corrosion problems. Corrosion leads to the change of surface morphology and the loss of section thickness, which results in the change of instability mode and failure mechanism of CFS structure. This paper mainly investigates the elastic local buckling behavior of corroded CFS columns. The surface morphology scanning test was carried out for eight CFS columns accelerated corrosion by the outdoor periodic spray test. The thin shell finite element (FE) eigen-buckling analysis was also carried out to reveal the influence of corrosion surface characteristics, corrosion depth, corrosion location and corrosion area on the elastic local buckling behaviour of the plates with four simply supported edges. The accuracy of the proposed formulas for calculating the elastic local buckling stress of the corroded plates and columns was assessed through extensive parameter studies. The results indicated that for the plates considering corrosion surface characteristics, the maximum deformation area of local buckling was located at the plates with the minimum average section area. For the plates with localized corrosion, the main buckling shape of the plates changed from one half-wave to two half-wave with the increase in corrosion area length. The elastic local buckling stress decreased gradually with the increase in corrosion area width and length. In addition, the elastic local buckling stress decreased slowly when corrosion area thickness was relatively large, and then tends to accelerate with the reduction in corrosion area thickness. The distance from the corrosion area to the transverse and longitudinal centerline of the plate had little effect on the elastic local buckling stress. Finally, the calculation formula of the elastic local buckling stress of the corroded plates and CFS columns was proposed.

A PHOTOELASTIC STUDY OF THE STRESS DISTRIBUTION ON THE MULTILOOP EDGEWISE ARCH WIRE (Multiloop Edgewise Arch Wire의 응력분포에 대한 광탄성학적 연구)

  • Lee, Sheung-Ho;Kim, Jeong-Gee
    • The korean journal of orthodontics
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    • v.24 no.4 s.47
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    • pp.969-982
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    • 1994
  • This study was designed to investigate the stress distribution, intensity and force mechanism derived from the MEAW by photoelastic stress analysis of the artificial teeth and surrounding bone composed of photoelastic material(PL-3) The findings of this study were as follows, 1. In case of no elastic on the MEAW with tip back, the moderate stress was observed on the molar and canine area, and the light stress was observed on the other area. 2. In case of the vertical elastic on the plain A.W, and the MEAW without tip back, the great stress was observed on the lateral incisor area, but on the MEAW with tip back, the moderate stress was observed on the anterior area and molar area. 3. In case of the C III elastic on plain A.W., the stress was concentrated on the anterior area hanged by elastic but on the MEAW without tip back, the stress was transmitted equally from the anterior area to the posterior teeth area. On the MEAW with tip back, the great stress was observed on the anterior and molar area. 4. In case of the C III elastic on the plain A.W., the stress was concentrated on the posterior area hanged by elastic but on the MEAW without tip back, the stress was transmitted equally from the posterior area to the anterior area. On the MEAW with tip back, the great stress was observed on the posterior area and the moderate stress was observed on the anterior area.

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The Comparision of the Static Balance, Contact Area, and Plantar Pressure of Flexible Flat Foot According to Elastic Taping

  • Hyeon-Seong Joo;Sam-Ho Park;Myung-Mo Lee
    • Physical Therapy Rehabilitation Science
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    • v.11 no.4
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    • pp.421-429
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    • 2022
  • Objective: The purpose of this study was to compare and analyze the effects of arch support taping on static balance, static/dynamic foot contact area, and ground reaction force during walking according to the types of elastic tapes with mechanical elasticity differences. Design: Cross-sectional study Methods: Twenty-six participants selected for flexible flat feet through the navicular drop test were randomly assigned to non-taping, Dynamic-taping, and Mechano-taping conditions. Static balance and foot contact area were compared in the standing posture according to arch support taping conditions, and foot contact area and ground reaction force were compared during walking. Results: There was no significant difference in static balance according to the taping condition in the standing position, but the foot contact area in the Mechano-taping condition showed a significant decrease compared to the non-taping condition (p<0.05). The foot contact area during walking significantly decreased in the Dynamic-taping and Mechano-taping conditions (p<0.05), but there was no significant difference between the ground reaction force. Conclusions: Based on the results of this study, it was confirmed that among the types of elastic taping, arch support taping using dynamic taping and Mechano-taping has the effect of supporting the arch with high elastic recovery. Any type of elastic tape can be used for arch alignment in flexible flat foot.

A Study on the Determination of Contact Area of a Plate on Elastic Half-Space (탄성지반 위에 놓인 평판의 접촉영역 결정에 관한 연구)

  • 정진환;이외득;김동석
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1998.10a
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    • pp.405-412
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    • 1998
  • According to the relative stiffness between the half-space and plate or loading condition, some parts of the plate can be separated from the half-space. The finite element procedure to determine the contact area by considering the distribution of contact pressure between plate and the elastic half-space is developed. The vertical surface displacements of the elastic half-space can be obtained through the integrations of the Boussinesq's solution for a point load. The rectangular plate on the elastic half-space is modeled by the 8-node rectangular and 6-node triangular elements and the Mindlin plate theory is used in oder to consider the transverse shear effect. In this study, the contact area may be determined approximately by the analysis with rectangular elements. From this results, the mesh pattern is modified by using triangular and rectangular elements. The contact area can be determined by the new mesh pattern with a relatively sufficient accuracy.

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Estimation Method of Local Elastic-Plastic Strain at Thinning Area of Straight Pipe Under Tension Loading (인장하중을 받는 직선 배관 감육부의 국부 탄소성 변형률 평가 방법)

  • An Joong-Hyok;Kim Yun-Jae;Yoon Kee-Bong;Ma Young-Wha
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.5 s.248
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    • pp.533-542
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    • 2006
  • In order to assess the integrity of pipes with local thinning area, the plastic strain as well as the elastic strain at the root of thinned region are required particularly when fluctuating load is applied to the pipe. For estimating elastic-plastic strain at local wall thinning area in a straight pipe under tensile load, an estimation model with idealized fully circumferential constant depth wall thinning area is proposed. Based on the compatibility and equilibrium equations a nonlinear estimation equation, from which local elastic-plastic strain can be determined as a function of pipe/defect geometry, material and the applied strain was derived. Estimation results are compared with those from detailed elastic-plastic finite element analysis, which shows good agreements. Noting that practical wall thinning in nuclear piping has not only a circular shape but also a finite circumferential length, the proposed solution for the ideal geometry is extended based on two-dimensional and three-dimensional numerical analysis of pipes with circular wall thinning.

INFLUENCE OF VARIOUS PROPERTIES OF POST AND CORE ON THE STRESS DISTRIBUTION IN ENDODONTICALLY TREATED TOOTH (다양한 포스트와 코어의 물성이 근관치료된 치근의 응력분산에 미치는 영향)

  • Cho Jin-Hyun;Lee Cheong-Hee
    • The Journal of Korean Academy of Prosthodontics
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    • v.44 no.1
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    • pp.10-19
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    • 2006
  • Statement of problem : The various kinds of properties of post and core may affect the stress distribution to the root of endodontically treated teeth Purpose: To evaluate the influence of various kinds of properties of post and core to the stress distribution to the root of endodontically treated teeth. Material and methods: Mandibular first premolar, prepared by general shape of post and core with gold crown, was used to two dimensional axisymmetric modeling for finite element analysis. Then property values of 8 different kinds of post and core was substituted for each. Finally, stress distribution shown areas around the root of post and core was analysed after applying 50N of vortical and oblique load. Results: 1. Stress value of oblique load was much higher than the maximum stress value of vertical load. 2. Under oblique load, very concentrated stress was located on post periapical area and variations in stress were very severe. Contrary to this, stress distribution was relatively uniform in vertical load. 3. Post materials with higher elastic modulus showed relatively more apically focused stress, and post materials with lower elastic modulus showed stress focused on cervical area on the axial wall of post. 4. Stress change according to the properties of core was shown only in the cervical area of post and below core as the higher elastic modulus, then increased in stress. 5. Post and core with medium value of elastic modulus showed relatively uniform stress distribution. Conclusions: Post materials with higher elastic modulus showed relatively more apically focused stress, and post materials with lower elastic modulus showed stress focused on cervical area on the axial wall of post. Stress change according to the properties of core was shown only in the cervical area of post and below core.

Characterization of Elastic Modulus and Work of Adhesion in Elastomeric Polymer through Micro Instrumented Indentation Technique (마이크로 압입시험기법의 응용을 통한 탄성체 고분자 소재의 역학적 특성화 및 계면 접합에너지 평가기법 연구)

  • Lee, Gyu-Jei;Kang, Seung-Kyun;Kang, In-Geun;Kwon, Dong-Il
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.1744-1748
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    • 2007
  • In this study, the Johnson-Kendall-Roberts (JKR) theory was combined with the instrumented indentation technique (IIT) to evaluate work of adhesion and modulus of elastomeric polymer. Indentation test was used to obtain the load-displacement data for contacts between Tungsten Carbide indenter and elastomeric polymer. And the JKR contact model, contrived to take viscoelastic effects of polymer into account, was applied to compensate the contact area and the elastic modulus which Hertzian contact model would underestimate and overestimate, respectively. Besides, we could obtain the thermodynamic work of adhesion by considering the surface energy in this contact model. In order to define the relation between JKR contact area and applied load without optical measuring of contact area, we used the relation between applied load and contact stiffness by examining the correlation between JKR contact area and stiffness through dimensional analysis with 14 kinds of elastomeric polymer. From this work, it could be demonstrated that the interfacial work of adhesion and elastic modulus of compliant polymer can be obtained from a simple instrumented indentation testing without area measurement, and provided as the main algorithm of compliant polymer characterization.

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Effect of Weld Elastic Modulus on Simulation of Stress Concentration and Fatigue Life for Boiler Vessel (ADINA & WINLIFE 활용한 압력용기 용접부 피로파괴 해석)

  • Choe, Byung Hak;Lee, Bum Gyu;Shim, Jong Heon;Park, Chan Sung;Kim, Jin Pyo;Park, Nam Gyu
    • Journal of Welding and Joining
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    • v.34 no.5
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    • pp.47-53
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    • 2016
  • The aim of this study is to consider effect of weld elastic modulus on simulations of stress concentration and fatigue life for pressure vessel. The investigations include analysis with ADINA and WINLIFE softwares for whole body model about using condition of the boiler vessel. Values of weld elastic modulus were divided by 5 steps in butt weld area of the boiler vessel body. The stress concentration of the butt weld more was increased in case of higher elastic modulus of weld area because of higher difference of material properties between matrix and weld. It was concluded that the fatigue lives were decreased along increasing stress concentration due to high elastic modulus of weld. The matrix microstructure was estimated as pearlitic structure of ${\alpha}$ ferrite and pearlite. And the microstructures of welds along 5 steps of elastic modulus were estimated as bainitic fine pearlite and martensite as increasing elastic modulus.

A sutudy of Elasticity Fabrics Expressed on Fashion Style (패션 작품(作品)에 표현(表現)된 신축성(伸縮性) 소재(素材)의 연구(硏究))

  • Choi, Jeong-Im;Jeon, Dong-Won;Kim, Jong-Jun
    • Journal of Fashion Business
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    • v.11 no.4
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    • pp.92-100
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    • 2007
  • The most emphasized materials in the modern fashion are the elastic materials with the advent of sportswear. In the area of elastic materials, the technology of foaming plastics became main research area. As novel materials, latex and neoprene based fabrics are emerging for the elastic material, among those elastic material staged by renowned fashion designers. We searched those works through literature and pictures, and examined the physical properties. Neoprene composite with filament knit fabrics are excellent in strength and water-proof. Latex fabrics gave smooth feel and elastic feel. These may be adequate for aesthetic textile material. Based on these characteristics, these techno-texitiles will find broad applications in the fashionable materials.