• Title/Summary/Keyword: axial tension

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A Study on Setting of Torque for Compressor Jointing Bolt (컴프레서 체결용 볼트의 적정 토크 설정에 관한 연구)

  • Kong, Yu Sik;Kim, Tae Wan
    • Tribology and Lubricants
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    • v.29 no.5
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    • pp.286-290
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    • 2013
  • When a threaded fastener is tightened, the torque-tension relationship is highly sensitive to two friction components: thread friction and head friction. In this study, we carried out friction experiments and analyses to determine the optimum clamping torque setting for bolt joints. First, we measured the coefficients of thread friction and head friction under the same running conditions of the bolt clamping process for lubricated and non-lubricated bolts. We also measured axial tension through bolt clamping tests using lubricated and non-lubricated bolts attached to a strain gauge. Finally, we compared the experiment and theoretical results.

Shear Load Transfer Characteristics of Drilled Shafts in Weathered Rocks (풍화암에 근입된 현장타설 말뚝의 하중 전이 특성)

  • Jeong, Sang-Seom;Cho, Sung-Han;Kim, Soo-Il
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.03a
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    • pp.85-106
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    • 2000
  • The load distribution and deformation of drilled shafts subjected to axial loads were evaluated by a load transfer approach. The emphasis was on quantifying the load transfer mechanism at the interface between the shafts and surrounding highly weathered rocks based on a numerical analysis and small-scale tension load tests performed on nine instrumented piles. An analytical method that takes into account the soil coupling effect was developed using a modified Mindlin's point load solution. Based on the analysis, a single-modified hyperbolic model is proposed for the shear transfer function of drilled shafts in highly weathered rocks. Through comparisons with field case studies, it is found that the prediction by the present approach is in good agreement with the general trend observed by in-situ measurements.

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Study on the performance of elastomeric O-ring subjected to foreign objects using finite-element analysis (유한요소해석을 이용한 이물질이 고무 오링에 미치는 영향과 성능 평가)

  • Pack, Inseok;Rhee, Heejang;Lee, Seoksoon
    • Journal of Aerospace System Engineering
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    • v.10 no.3
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    • pp.52-58
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    • 2016
  • The elastomeric O-ring is the most-commonly-used seal due to its excellent sealing capacity, and its availability in various costs and sizes; furthermore, its importance has lasted over a long duration. However, a dearth of research exists in Korea regarding the elastomeric O-ring and the corresponding techniques. The constituent parts of elastomeric rubber are important; to determine their properties, the uni-axial tension and equi-biaxial tension need to be tested. Also, the non-linear analysis method reduces the design cost. An O-ring failure causes leaks and vibration. In this paper, foreign objects are used to affect an O-ring and its performance so that all angles of the O-ring design can be considered. This paper presents a solution for the O-ring-failure problem using a finite-element analysis.

A Study on the Stabilization Process of Truss Structure Stabilized by Cable Tension (장력안정트러스 구조물의 안정화기법에 관한 연구)

  • 권택진;한상을;김충한;최옥훈
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1996.10a
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    • pp.330-339
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    • 1996
  • The primary objective of this paper is to grasp characteristics of unit system, for the stabilization of stablized truss structure that is an assemblage of unit system by prestress. This unit system is composed of a central post and eight cables, and is connected by hinge joints, and stabilized by the self-equilibrated stress system. As this unit structures itself is a statically closed and stabilized system individually, it can be employed to assemble a structure with a variety of configuration. In this paper, for the stabilization of truss structure stabilized by cable tension, it is proposed the self-equilibrated axial mode equation and the range of the various geometrical parameter about unit system.

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Estimating Tensile Force of Hangers in Suspension Bridges Using SI Technique (SI 기법을 이용한 현수교 행어케이블의 장력 추정)

  • Park Tae-Hyo;Moon Seok-Yong;Kim Byeong-Hwa
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.786-793
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    • 2006
  • For the purpose of developing a vibration-based tension force evaluation procedure for hangers in suspension bridges, a 3D finite element model of hangers is constructed in this paper. With the developed finite element formulation, a frequency-based sensitivity-updating algorithm is applied to identify the target cable system the proposed method is also able to identify the flexural rigidity. the axial rigidity, and the torsion rigidity of a cable. For a field application, a vibration test on hangers of the Yong Jong Grand Suspension Bridge is carried out and the collected data is used to verify the proposed method.

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Useful Lifetime Evaluation of Rubber Component for Elevator Cabin (승강기용 방진고무부품 특성 및 사용수명 평가)

  • Woo, Chang-Su;Park, Hyun-Sung
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.576-580
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    • 2008
  • Rubber material properties and useful life evaluation are very important in design procedure to assure the safety and reliability of the rubber components. In this paper, the evaluation of characteristics and useful life prediction of rubber component for elevator cabin were experimentally investigated. The material test and accelerated heat-aging test were carried. Rubber material constants were obtained by curve fittings of simple tension, pure shear and bi-axial tension test data. Heat aging test results changes as the threshold are used for assessment of the useful life and time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot. By using the rubber material and component test several useful life prediction equations for rubber component were proposed. Predicted useful life of rubber component for elevator cabin agreed fairly with the experimental lives.

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Behavior of tunnel form buildings under quasi-static cyclic lateral loading

  • Yuksel, S. Bahadir;Kalkan, Erol
    • Structural Engineering and Mechanics
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    • v.27 no.1
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    • pp.99-115
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    • 2007
  • In this paper, experimental investigations on the inelastic seismic behavior of tunnel form buildings (i.e., box-type or panel systems) are presented. Two four-story scaled building specimens were tested under quasi-static cyclic lateral loading in longitudinal and transverse directions. The experimental results and supplemental finite element simulations collectively indicate that lightly reinforced structural walls of tunnel form buildings may exhibit brittle flexural failure under seismic action. The global tension/compression couple triggers this failure mechanism by creating pure axial tension in outermost shear-walls. This type of failure takes place due to rupturing of longitudinal reinforcement without crushing of concrete, therefore is of particular interest in emphasizing the mode of failure that is not routinely considered during seismic design of shear-wall dominant structural systems.

A numerical tension-stiffening model for ultra high strength fiber-reinforced concrete beams

  • Na, Chaekuk;Kwak, Hyo-Gyoung
    • Computers and Concrete
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    • v.8 no.1
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    • pp.1-22
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    • 2011
  • A numerical model that can simulate the nonlinear behavior of ultra high strength fiber-reinforced concrete (UHSFRC) structures subject to monotonic loadings is introduced. Since engineering material properties of UHSFRC are remarkably different from those of normal strength concrete and engineered cementitious composite, classification of the mechanical characteristics related to the biaxial behavior of UHSFRC, from the designation of the basic material properties such as the uniaxial stress-strain relationship of UHSFRC to consideration of the bond stress-slip between the reinforcement and surrounding concrete with fiber, is conducted in this paper in order to make possible accurate simulation of the cracking behavior in UHSFRC structures. Based on the concept of the equivalent uniaxial strain, constitutive relationships of UHSFRC are presented in the axes of orthotropy which coincide with the principal axes of the total strain and rotate according to the loading history. This paper introduces a criterion to simulate the tension-stiffening effect on the basis of the force equilibriums, compatibility conditions, and bond stress-slip relationship in an idealized axial member and its efficiency is validated by comparison with available experimental data. Finally, the applicability of the proposed numerical model is established through correlation studies between analytical and experimental results for idealized UHSFRC beams.

Mechanical Characteristics of Cable Truss Roof Systems (케이블 트러스 지붕 시스템의 역학적 특성)

  • Park, Kang-Geun;Lee, Dong-Woo
    • Journal of Korean Association for Spatial Structures
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    • v.16 no.2
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    • pp.89-96
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    • 2016
  • Cable structures are lightweight structures of flexible type, cable members have only axial stiffness related to tension, they can carry neither bending nor compression. This study is the analysis of cable truss systems are composed of upper and low cables by connecting bracing cables, the structural principle is based on a tensegrity system by using bracing tension members, discontinuous compression members and continuous tension members. A hanging roof of cable truss system is too flexible against vertical loads, most cable members are stabilized by connecting the prestressed upper and lower cable by bracing cables. A cable truss roof system is formed by adding a set of cables with reverse curvature to the suspension cables. With the sets of cables having opposite curvature to each other, cable truss is able to carry vertical load in both upward and downward direction with equal effectiveness, and then a cable truss acts as load bearing elements by the assemble of ridge cables, valley cables and bracing cables. This paper will be shown the geometric non-linear analysis result of cable truss systems with various sag ratio for deflections and tensile forces, the analytical results are compared with the results of other researchers.

Investigation of shear lag effect on tension members fillet-welded connections consisting of single and double channel sections

  • Barkhori, Moien;Maleki, Shervin;Mirtaheri, Masoud;Nazeryan, Meissam;Kolbadi, S.Mahdi S.
    • Structural Engineering and Mechanics
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    • v.74 no.3
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    • pp.445-455
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    • 2020
  • Shear lag phenomenon has long been taken into consideration in various structural codes; however, the AISC provisions have not proposed any specific equation to calculate the shear lag ratio in some cases such as fillet-welded connections of front-to-front double channel sections. Moreover, those equations and formulas proposed by structural codes are based on the studies that were conducted on riveted and bolted connections, and can be applied to single channel sections whilst using them for fillet-welded double channels would be extremely conservative due to the symmetrical shape and the fact that bending moments will not develop in the gusset plate, resulting in less stress concentration. Numerical models are used in the present study to focus on parametric investigation of the shear lag effect on fillet-welded tension connection of double channel section to a gusset plate. The connection length, the eccentricity of axial load, the free length and the thickness of gusset plate are considered as the key factors in this study. The results are then compared to the estimates driven from the AISC-LRFD provisions and alternative equations are proposed.