• Title, Summary, Keyword: 체결력

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Optimum Design of Lock Snap-fit Using Design of Experiment (실험계획법을 이용한 이탈방지 스냅핏의 최적설계)

  • Son, In-Seo;Shin, Dong-Kil
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.8
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    • pp.378-385
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    • 2017
  • This study investigated the design of a snap fit, which is widely used for fastening plastic parts. We analyzed the assembly mechanism of a lock snapfit, measured the assembly force and separation force based on the design of experiments, and derived a regression equation through an analysis of variance. The response surface methodology was also used. Polybutylene terephthalate was used to fabricate specimens, and the assembly force and separation force were measured using a micro-tensile tester. The length, width, thickness, and interference were considered as factors. A second-order regression model was used to derive the regression equation. The assembly force decreased with increasing length and width, but it increased with increasing thickness and interference. The finite element method was used to analyze the assembly mechanics. The width decreased the assembly force by increasing the ductility. The influences of the factors for low assembly force and high release force were shown to be opposite to each other. It was necessary to design a structure that minimized the assembly force while maintaining an appropriate level of separation force.

Influence of Initial Clamping Force of Tension Clamp on Performance of Elastic Rail Fastening System (텐션클램프의 초기 체결력이 탄성레일체결장치의 성능에 미치는 영향)

  • Lee, Dong Wook;Choi, Jung Youl;Baik, Chan Ho;Park, Yong Gul
    • Journal of The Korean Society of Civil Engineers
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    • v.33 no.3
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    • pp.1243-1251
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    • 2013
  • The purpose of this study is to investigate the influence of initial clamping force of tension clamp on the performance of an elastic rail fastening system used in sharp curve track. In this study, the initial clamping force and the increasing lateral wheel loads were conducted in the analytical and experimental study, i.e., finite element analysis, laboratory and field test. Using the analytical and experimental results, the performance of the tension clamp was investigated. It was found that the stress of tension clamp depends on the initial clamping force. Therefore the initial clamping force appeared to directly affect the compression stress of the tension clamp. It was found that the compression stress of tension clamp was transferred to the tensile stress by applied the lateral wheel load in service sharp curve track. Further, it was concluded that the initial clamping force was applied on the strengthening force for the tension clamp and then the appropriate initial clamping force was important to ensure a stable performance and long term endurance of tension clamp.

Simplified Finite Element Model of an Anchor Bolt Inserted Through Concretes Considering Clamping Forces (체결력을 고려한 콘크리트 삽입 앵커볼트의 간편 유한요소 모델)

  • Noh, Myung Hyun;Lee, Sang Youl;Park, Kyu Sik
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.26 no.4
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    • pp.293-300
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    • 2013
  • In this study we proposed a simplified finite element model of anchor bolt system inserted through concrete structures considering clamping forces. The three different finite element types using LS-DYNA are applied for numerical efficiency of the anchor bolt modeling. Combined beam and solid elements are used to reflect the tension state at internal part of anchor bolt due to torques. The clamping forces due to torques are considered by introducing a compression for a nut plane modeled by beam elements. The numerical examples show good agreement with different element types. Parametric studies are focused on the various effects of different element types on the induced axial and shear forces of anchor bolts considering clamping forces.

A Study on Constitution of Plant Safety Inspection System for Measuring Joint Axial Force of High Tension Bolt (고장력 볼트의 체결축력 측정을 위한 설비 안전 검사 시스템 구축에 관한 연구)

  • Kim, J.Y.;Park, S.G.;Kim, H.S.;Kim, C.H.;You, S.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.15 no.2
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    • pp.371-377
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    • 1995
  • By using ultrasonic waves, we obtained conclusion from the experiment for measuring joint axial force of high tension bolt. The conclusion is followed. : From the high tension bolts used at turbine of Thermoelectric Power Plant, we obtained the equation of calculating joint axial force that is ${\sigma}=\frac{{\Delta}BPD}{j{\times}{\Sigma}{\delta}}$. By using IBM PC, which is inputed by the equation for calculating joint axial force of high tension bolts, we got joint axial force of high tension bolts form beam path of ultrasonic waves. Furrther, we can identify that constitution of plant safety inspection system is possible.

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Study on The Suggested Curve Fitting Algorithm for Bolt Clamping Force Measurement (볼트 체결력 측정을 위해 제안한 커브피팅 알고리즘에 관한 연구)

  • Lee, Ki-Won
    • Journal of Satellite, Information and Communications
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    • v.7 no.3
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    • pp.94-98
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    • 2012
  • In order to serve the exact torque clamping force, the torque measurement system use the curve fitting algorithm by the least square. The corrected least square curve fitting algorithm which suggested in this paper can surpport more exact clamping force for fastner in variable industry field using the torque. At first, This paper introduces mathematical modeling for curve fitting algorithm, and simulate it. As a result, the corrected least square algorithm have shown lower standard error value than that of the used algoritm with torque, and so this corrected least square algorithm prove high accuracy than nomal least square algorithm. The suggested algorithm will contribute to improvement of cost and safety on industry field with bolt clamping force for precision industry parts, electronics parts, aircraft, aerospace, etc.

An Experimental Study on the Static Load Capacity of T-Type Tension Joints with High Tension Bolt (고장력볼트 T-인장이음의 정적내력에 관한 실험적 연구)

  • Lee, Seung Yong;Choi, Jun Hyeok;Kim, Kyong Tae
    • Journal of Korean Society of Steel Construction
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    • v.27 no.1
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    • pp.53-61
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    • 2015
  • The tension type joint is a mechanically very efficient connection method, as it directly uses the load capacity of base metal or high tension bolt, the reduction of the number of drilling hole and fastening and the fatigue resistance. It is applied to the joint of girder and cross beam, horizontal joints of towers, beam to column joints, the secondary member joints of deck floor ends, and brackets. In this paper, static load tests for the T-type tension joint were conducted to investigate the structural behavior of the joint. The parameters were bolt diameter, flange thickness, and the reduction of clamping force of the joint. The failure modes and load capacity of joints and the effects of flange thickness, bolt diameter and clamping force were investigated.

Study on the Profile of Nut Bearing Surface and the Torque Coefficient of a High Strength Bolt Set (고장력 볼트세트의 자리면형상과 토크계수에 관한 연구)

  • Lee, Baek Joon;Sohn, Seung Yo
    • Journal of Korean Society of Steel Construction
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    • v.12 no.2
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    • pp.143-150
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    • 2000
  • Depending upon the combination of tolerances specified in the standards on bolt, nut and washer for high tension bolt sets, there arises center-to-center deviation between bolt and washer. This deviation nay cause loss of effective contact area between nut- and washer-faces, which leads to some dispersion of the torque coefficient K. By adapting circular arc surface instead of flat surface for the nut, it is shown through numerical analyses that the dispersion of the torque coefficient can be minimized. In this way, optimum radius of curvature of the nut bearing surface is proposed.

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Time Dependent Reduction of Clamping Forces of High Strength Bolt F13T (시간에 따른 F13T 고장력 볼트의 체결력 감소)

  • Jo, Jae Byung;Seong, Taek-Ryong
    • Journal of The Korean Society of Civil Engineers
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    • v.29 no.4A
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    • pp.291-297
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    • 2009
  • Relaxation of high strength bolts was investigated. Block type and splice type specimens were fabricated with different types of bolts and different clamping lengths. Bolts were tightened to the specified torque. Clamping forces were measured through strain gauges installed on the shafts of bolts, while specimens were kept in a constant temperature and humidity. In all cases, ratio of clamping force reduction is less than 10%. Test results of different types of specimens and bolts and different clamping lengths were compared each other by using a simple model, which is suggested in this study for the estimation of bolt relaxation. The suggested model shows reasonably good agreements with test results for all cases. No difference is found between F13T and F10T bolts, but Dacro coated bolts shows higher relaxation than black bolts by approx. 30%. And also the comparison of test results shows that ratios of bolt relaxation become larger as clamping lengths of bolt shorter and the number of faying surfaces greater.

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An Experimental Study to Evaluate the Stiffness of Fastening Systems - Translational Stiffness along the Vertical Axis of Rail, Rotational Stiffness along the Strong Axis of Rail - (체결장치의 강성 평가를 위한 실험적 연구 - 레일 연직방향 병진강성, 레일 강축에 대한 회전강성 -)

  • Kim, Jung-Hun;Han, Sang-Yun;Lim, Nam-Hyoung;Kang, Young-Jong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.4
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    • pp.71-78
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    • 2008
  • In the case of the railway bridges, uplift forces were occurred at the edge of the segments when vehicular loads were applied. These forces caused the compressive and tensile forces in the fastening system. In the past, a structural analysis has been performed to investigate the safety of fastening system which was modeled with one directional spring elements based on the compressive test of fastening system. In this case, the stiffness of the spring element was obtained from experimental study which was conducted by compressive load. Therefore, to perform rational and exact structural analysis, the translational stiffness of the fastening system obtained from the experimental study applied the tensile load and the rotational stiffness should be considered because it was occurred the tensile force as well as the compressive force in fastening system. In this study, an elastic and inelastic experimental study was performed for six specimens. The translational stiffness along the vertical axis of rail and the rotational stiffness along the strong axis of rail were investigated, also structural behavior of the fastening system was analyzed.

Structural Analysis of High Precision Reflector Using Finite Element Analysis (유한요소해석법을 이용한 고정밀 반사경의 구조 해석)

  • Lee, Sang-Yong;Kim, Ghiseok;Kim, Geon-Hee;Lee, Young-Shin
    • Journal of the Korean Society for Nondestructive Testing
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    • v.33 no.2
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    • pp.154-159
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    • 2013
  • In this paper, the effect of bolt clamping force and form accuray of contact surface between mirror and mount on mirror surface was studied. Normally, mirror used in reflecting optical system was assembled with mount by bolts or adhesive. In this case, the tension caused by bolt clamping force or adhesive force may distort the mirror surface. Also, form accuracy error of the contact surface have a negative impact on wrenched mirror surface which assembled by bolts or adhesive. In this study, stress and distorted displacements on mirror surface were analyzed according to the different contact surface form accuracies and bolt clamping forces by using the finite element analysis method.