• Title/Summary/Keyword: Deformation Tube

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The Experimental Study on Axial Loaded Concrete Filled Steel Tube Confined by Carbon Fiber Sheet (탄소섬유쉬트로 구속된 콘크리트충전 각형강관기둥의 단조압축실험)

  • Park, Jai Woo;Hong, Young Kyun;Hong, Gi Soup;Lee, Seoung Hee;Choi, Sung Mo
    • Journal of Korean Society of Steel Construction
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    • v.21 no.3
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    • pp.311-320
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    • 2009
  • This paper presents the experimental results of an experiment on the current rectangular CFT columns and rectangular CFT columns additionally confined by carbon fiber sheets(CFS) under axial loading. The main experimental parameters were the layer numbers of the CFS and the depth-to-thickness ratio. Nine specimens were prepared according to the experimental parameter plans, and axial compression tests were conducted. From the tests, the failure procedure, the load-axial deformation curve, the maximum axial strength, and the deformation capacity of the CFT columns and the confined CFT columns were compared. Finally, it was seen that the maximum axial strengths of the CFT increased more significantly than that of the current CFT columns because of delayed local buckling.

A mathematical model to recover missing monitoring data of foundation pit

  • Liu, Jiangang;Zhou, Dongdong;Liu, Kewen
    • Geomechanics and Engineering
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    • v.9 no.3
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    • pp.275-286
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    • 2015
  • A new method is presented to recover missing deformation data of lateral walls of foundation pit when the monitoring is interrupted; the method is called Dynamic Mathematical Model - Parameter Interpolation. The deformation of lateral walls of foundation pit is mainly affected by the type of supporting structure and the situation of constraints, therefore, this paper mainly studies the two different kinds of variation law of deep horizontal displacement when the lateral walls are constrained or not, proposes two dynamic curve models of normal distribution type and logarithmic type, deals with model parameters by interpolating and obtains the parameters of missing data, then missing monitoring data could be Figured out by these parameters. Compared with the result from the common average method which is used to recover missing data, in the upper 2/3 of the inclinometer tube, the result by using this method is closer to the actual monitoring data, in the lower 1/3 part of the inclinometer tube, the result from the common average method is closer to the actual monitoring data.

A Study on the Structural Design Approach to Improve Shockproof Characteristic in Cathode Ray Tube (음극선관의 내충격 특성 향상을 위한 구조 설계에 관한 연구)

  • Park, Sang-Hu;Kim, Won-Jin;Lee, Boo-Youn
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.8
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    • pp.100-105
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    • 2000
  • In this study the structural design concepts of main parameters of a Cathode Ray Tube(CRT) such as frame spring and shadow mask were proposed to guarantee a failure-proof CRT under mechanical shock. With computer simulation and experiments some information on the structural design concept was obtained as followings: the frame and the shadow mask of the CRT needed designing to increase strength so double-beads shape at the corner of frame was newly designed for it, And the spring which interconnected frame with panel glass was required to deform elastically for the purpose of absorbing the shock energy in the direction of drop. A new type of spring 'twisting spring' was designed to achieve the flexibility in that direction. By using it the deformation energy of a shadow mask could reduced to some degree. To accomplish those simulations commerical codes Pam-Crash and I-DEAS were used and a typical CRT was analyzed as an example to prove the usefulness of this study.

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Nonlinear vibration of functionally graded nano-tubes using nonlocal strain gradient theory and a two-steps perturbation method

  • Gao, Yang;Xiao, Wan-Shen;Zhu, Haiping
    • Structural Engineering and Mechanics
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    • v.69 no.2
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    • pp.205-219
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    • 2019
  • This paper analyzes nonlinear free vibration of the circular nano-tubes made of functionally graded materials in the framework of nonlocal strain gradient theory in conjunction with a refined higher order shear deformation beam model. The effective material properties of the tube related to the change of temperature are assumed to vary along the radius of tube based on the power law. The refined beam model is introduced which not only contains transverse shear deformation but also satisfies the stress boundary conditions where shear stress cancels each other out on the inner and outer surfaces. Moreover, it can degenerate the Euler beam model, the Timoshenko beam model and the Reddy beam model. By incorporating this model with Hamilton's principle, the nonlinear vibration equations are established. The equations, including a material length scale parameter as well as a nonlocal parameter, can describe the size-dependent in linear and nonlinear vibration of FGM nanotubes. Analytical solution is obtained by using a two-steps perturbation method. Several comparisons are performed to validate the present analysis. Eventually, the effects of various physical parameters on nonlinear and linear natural frequencies of FGM nanotubes are analyzed, such as inner radius, temperature, nonlocal parameter, strain gradient parameter, scale parameter ratio, slenderness ratio, volume indexes, different beam models.

Behavior of Circular Hollow Section R.C Member with Internal Corrugated Steel Tube (파형강관을 삽입한 중공원형단면 철근콘크리트 부재의 거동에 관한 연구)

  • Im, Jung-Soon;Kim, Sung-Chil;Jo, Jae-Byung;Lee, Soo-Keun
    • Journal of the Korean Society of Hazard Mitigation
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    • v.3 no.1 s.8
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    • pp.123-131
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    • 2003
  • An experiment was carried out to investigate the mechanical behaviour of the circular hollow section reinforced concrete member with internal corrugated steel tube. A specimen, 50cm in diameter and 340cm in length, was made and tested by 3 points bending. The test load was increased slowly (quasi static) to the failure or unacceptable deformation. During the test, lateral displacement at mid point and longitudinal displacement of extreme fiber on compressive and tensile side of the specimen were measured. The measured data were analysed and compared with calculated results for the equivalent member without inserted corrugated steel tube. The comparison shows that the flexural strength and ductility of hollow section reinforced concrete members can be improved by inserting corrugated steel tubes inside.

A Study on the Ultimate Strength of Tube-Gusset Connection Considering Eccentricity (편심이 고려된 강관-가셋트 접합부의 극한 내력)

  • Kim, Woo Bum
    • Journal of Korean Society of Steel Construction
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    • v.13 no.2
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    • pp.201-210
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    • 2001
  • A numerical analysis and experimental study were performed to investigate the behavior and strength of tube-gusset connection subjected to axial and lateral forces. To investigate the behavior of the connections, experiment was conducted by applying three directional loads. Local buckling and local plastic bending deformation of the connection were observed from the test. Analytical results were compared with test results for the limited cases. Primary interests here are the effect of eccentricity on the strength of the connection. To suggest a formula for the strength of tube-gusset connection, lateral forces were replaced with equivalent wall moment and eccenrtric vertical component force of lateral force. Ultimate strength formula for the each force was proposed. Finally, nondimensionalized ultimate strength interaction relationships between the wall moment of tube($M_w$), vertical axial force($P_v$), and eccentric vertical component of lateral force($P_e$) were formulated through parametric study.

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Capacity of Concrete Filled Carbon Tube Columns Based on the Comparison of Ductility and Energy Dissipation Capacity (연성도 및 에너지 소산능력 비교에 따른 콘크리트충전 탄소섬유튜브 기둥의 성능)

  • Lee, Kyoung-Hun;Hong, Won-Kee;Lee, Young-Hak;Kim, Hee-Cheul
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.1 s.53
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    • pp.29-35
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    • 2007
  • Flexural capacity estimation test of concrete filled carbon tube (CFCT) column under the cyclic lateral load was carried out in this study. Thickness of carbon tube and winding angles of carbon fiber were chosen as test parameters and two types of column with square and circular sections were manufactured. To act axial and lateral load, three dynamic actuators were used and all specimens were made with actual size. Flexural stiffness, ability of deformation, energy dissipation capacity and ductility behavior. of CFCT column were analyzed with test data.

Experimental Evaluation on the Thermal Stress Due to Ice Plugging of Tubes in Nuclear Power Plant (배관의 Ice Plugging에 의하여 유발되는 열응력의 실험적 규명)

  • Park, Young-Don;Lee, Min-Woo;Ku, Tae-Wan;Kim, Kui-Soon;Kang, Beom-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.23 no.7 s.166
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    • pp.1094-1103
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    • 1999
  • Ice-plugging of tube in nuclear power plant has been widely used for the purpose of preventing flow of the tube temporarily like a valve. Most common plugging method employs Liquid Nitrogen Gas of $-196^{\circ}C$. According to the change of tube materials and its dimension, the thermal stress caused from the application of the frozen gas can be varied. In this research, a series of experiments have been carried out to inspect the effect of tube geometry on thermal stresses induced due to ice-plugging. Two typical dimension of stainless and mild steels of 3 and 6 inch diameters were used for the experiments. Each critical spots were checked using strain rosette gages. Another inspection was made on the pressure and temperature of the fluid. It is shown that significant thermal stress level which can cause plastic deformation of failure has not been noticed in this series of experiments.

A new and simple analytical approach to determining the natural frequencies of framed tube structures

  • Mohammadnejad, Mehrdad;Kazemi, Hasan Haji
    • Structural Engineering and Mechanics
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    • v.65 no.1
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    • pp.111-120
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    • 2018
  • This paper presents a new and simple solution for determining the natural frequencies of framed tube combined with shear-walls and tube-in-tube systems. The novelty of the presented approach is based on the bending moment function approximation instead of the mode shape function approximation. This novelty makes the presented solution very simpler and very shorter in the mathematical calculations process. The shear stiffness, flexural stiffness and mass per unit length of the structure are variable along the height. The effect of the structure weight on its natural frequencies is considered using a variable axial force. The effects of shear lag phenomena has been investigated on the natural frequencies of the structure. The whole structure is modeled by an equivalent non-prismatic shear-flexural cantilever beam under variable axial forces. The governing differential equation of motion is converted into a system of linear algebraic equations and the natural frequencies are calculated by determining a non-trivial solution for the system of equations. The accuracy of the proposed method is verified through several numerical examples and the results are compared with the literature.

FE Simulation of Extrusion Process for Al Multi Cell Tube According to the Changes of the Porthole Shape (포트홀 형상 변화를 고려한 Al 멀티셀 튜브 압출공정 해석)

  • Lee Jung Min;Kim Dong Hwan;Ho Jo Hyung;Kim Byung Min
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.8 s.239
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    • pp.1146-1152
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    • 2005
  • Recently, multi cell tube which is used for a cooling system of automobiles is mainly manufactured by the conform extrusion but this method is inferior as compared with direct extrusion in productivity per the unit time and in the equipment investment. Therefore, it is essential for the conversion of direct extrusion with porthole die. The direct extrusion with porthole die can produce multi cell tube which has the competitive power in costs and qualities compared with the existing conform extrusion. This study is designed to evaluate metal flow, welding pressure, extrusion load, tendency of mandrel deflection that is affected by variation of porthole shape in porthole die. Estimation is carried out using finite element method under the non-steady state. Also this study was examined into the cause of mandrel fracture through investigating elastic deformation of mandrel during the extrusion.