• Title/Summary/Keyword: steel model

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Analysis of the Stress Characteristics of Double Layered Tube at Elevated Temperature (고온에서 이중튜브의 열응력특성해석)

  • Kim, E.H.;Jang, J.H.;Park, S.P.;Moon, Y.H.
    • Transactions of Materials Processing
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    • v.19 no.7
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    • pp.405-410
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    • 2010
  • Double layered tube that has been used for transportation and oil piping system is occasionally exposed to elevated temperature. The change in stress state at elevated temperature is important for the safe design of double layered tube. In this study, the variation of stress state for hydroformed double layered tube of which inner tube is stainless steel and outer tube is mild steel has been analytically analyzed. To characterize the thermal stress at elevated temperature, analytical model to provide thermal stresses between outer tube and inner tube was developed by using theories of elasticity and Lame equation. The feasibility of analytical model is verified by finite element analysis using ANSYS $CLASSIC^{TM}$, commercially available code. The variation of thermal stress at various thickness combination of inner and outer tube has also been investigated by proposed analytical model.

Seismic Performance Evaluation of RC Bridge Piers by Macro Mathematical Model (Macro해석모델에 의한 RC교각의 내진 성능 평가)

  • Lee Dae Hyoung;Park Chang Kyu;Kim Hyun Jun;Chung Young Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05a
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    • pp.207-210
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    • 2005
  • The objective of this research is to evaluate of seismic performance for reinforced concrete bridge piers with lap splices of longitudinal reinforcement steels using predict of nonlinear hysteric behavior. For the purpose, analytical trilinear hysteretic model has been used to simulate the force displacement hysteretic curve of RC bridge piers under repeated reversal loads. The moment capacity and corresponding curvature in the plastic hinge have been determined, and the enhanced hysteretic behavior model by five different kinds of branches has been proposed for modeling the stiffness variation of RC section under cyclic loading. The strength and stiffness degradation index are introduced to compute the hysteretic curve vary confinement steel ratio. In addition, the modified curvature factor has been introduced to forecast of seismic performance of longitudinal steel lap spliced and retrofitted specimens.

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Cracking Behavior of RC Panels under Biaxial Tension (이축인장을 받는 철근콘크리트 패널의 균열 거동)

  • 곽효경;김도연
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.10a
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    • pp.599-606
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    • 2003
  • An analytical model which can simulate the post-cracking nonlinear behavior of reinforced concrete (RC) members such as bars and panels subjected to uniaxial and biaxial tensile stresses is presented. The proposed model includes the description of biaxial failure criteria and the average stress-strain relation of reinforcing steel. Based on strain distribution functions of steel and concrete after cracking, average response of an embedded reinforcement, a criterion to consider the tension-stiffening effect is proposed using the concept of average stresses and strains. The validity of the introduced model is established by comparing the analytical predictions for reinforced concrete tension members with results from experimental studies. Finally, correlation studies between analytical results and experimental data from biaxial tension test are conducted with the objective to establish the validity of the proposed models and identify the significance of various effects on the response of biaxially loaded reinforced concrete panels.

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Strength Reliability Analysis of Continuous Steel Fiber Reinforced Concrete Beam (강섬유 보강 철근콘크리트 연속보의 강도신뢰성 해석)

  • 유한신;곽계환;조효남
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.10a
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    • pp.267-273
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    • 2003
  • Steel fiber may be used to raise the effectiveness and safety of reinforced concrete structure and to relax its brittle-fracture behavior. However it is to be clearly stated that the uncertainty for the strength of fiber reinforced concrete(SFRC) is rather increased. Therefore, it is necessary to evaluate the safety of SFRC beam using reliability analysis incorporating realistic uncertainty. This study presents the statistical data and proposes the limit state model to analyze the reliability of SFRC bear In order to verify the efficiency of the proposed limit state model, its numerical application and sensitivity analysis were performed for a continuous SFRC beam. From the results of the numerical analysis, it is founded that the reliability of SFRC beam is significantly difficult from the conventional RC beams and proposed limit state model (or SFRC beam is more rational compared with that for conventional RC beams. Then it may be stated that the reliability analysis of SFRC beams must be carried out for the development of design criteria and the safety assessment.

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Study on the development of ultrasonic gas flowmeter (초음파 가스 유량계 개발 연구)

  • Hwang, Won-Ho;Park, Sang-Gug;Yang, Kyu-Hong;Jhang, Kyung-Young
    • Proceedings of the KSME Conference
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    • 2001.06b
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    • pp.76-81
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    • 2001
  • Ultrasonic flowmeters have more advantages than the conventional method using pressure-difference. In these reasons, many advanced nations are already selling the commercial model. In RIST, we have been developed ultrasonic gas flow meter for the localization since a project was been contracted with POSCO in 1997. This paper describes a new ultrasonic gas flowmeter. This ultrasonic gas flowmeter is developed for accurate measurement of gases in a harsh environmental conditions. It is especially suited for measuring LDG, COG, BFG gases produced in iron & steel making process. In this study, we had developed the commercial model about the first tested model and applied a completed system to the POSCO gas line. Its performance has already well been proven by extensive field tests for several months in POSCO, iron & steel making company.

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On the structural behavior of ship's shell structures due to impact loading

  • Lim, Hyung Kyun;Lee, Joo-Sung
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.10 no.1
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    • pp.103-118
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    • 2018
  • When collision accident between ships or between ship and offshore platform occurs, a common phenomenon that occurs in structures is the plastic deformation accompanied by a large strain such as fracture. In this study, for the rational design against accidental limit state, the plastic material constants of steel plate which is heated by line heating and steel plate formed by cold bending procedure have been defined through the numerical simulation for the high speed tension test. The usefulness of the material constants included in Cowper-Symonds model and Johnson-Cook model and the assumption that strain rate can be neglected when strain rate is less than the intermediate speed are verified through free drop test as well as comparing with numerical results in several references. This paper ends with describing the future study.

Assessment of Bond-Slip Interface Model with Concrete and CFRP Plates (콘크리트와 탐소섬유판 계면의 본드-슬립모델 산정)

  • Yang Dong suk;Koh Byung Soon;Park Sun Kyu;You Young Chan
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.635-638
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    • 2004
  • External bonding of steel plates has been used to strengthen deficient reinforced-concrete structures since the 1960s. In recent years, fiber-reinforcde polymer(FRP) plates have been increasingly used to replace steel plates due to their superior properties. This paper is concerned with anchorage failure due to crack propagation parallel to the boned plated near or along the adhesive/concrete interface, staring from the critically stressed position toward the anchored end of the plates. Factor of bond-slip interface model is average bond stress, effective length, slip volume and fracture energy. The aim of the present paper is to provide a comprehensive assessment of bond-slip interface model with concrete and CFRP plates.

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Modelling the Densification Behaviour of Powders Considering Diffusion and Power-Law Creep Mechanisms during Hot Isostatic Pressing (열간정수압압축 시 확산기구 및 Power-law크립기구를 고려한 분말 치밀화거동의 모델링)

  • 김형섭
    • Journal of Powder Materials
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    • v.7 no.3
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    • pp.137-142
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    • 2000
  • In order to analyze the densification behaviour of stainless steel powder compacts during hot isostatic pressing (HIP) at elevated temperatures, a power-law creep constitutive model based on the plastic deformation theory for porous materials was applied to the densification. Various densification mechanisms including interparticle boundary diffusion, grain boundary diffusion and lattice diffusion mechanisms were incorporated in the constitutive model, as well. The power-law creep model in conjunction with various diffusion models was applied to the HIP process of 316L stainless steel powder compacts under 50 and 100 MPa at $1125^{\circ}C$. The results of the calculations were verified using literature data. It could be found that the contribution of the diffusional mechanisms is not significant under the current process conditions.

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Experiment of tong-neck Flange Cold Forging Process Using Plasticine (플라스티신을 이용한 롱넥 플랜지 냉간 단조 공정의 모사 실험)

  • 이호용;임중연;이상돈
    • Transactions of Materials Processing
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    • v.10 no.1
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    • pp.67-74
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    • 2001
  • The cold forging process to produce a long-neck flange is investigated by using model material test. The two stage process with optimum design condition is examined using plasticine, which is suitable to model steel at room temperature. The similarity theory is employed to estimate the forging load of each sequence by strict application of similarity condition between steel(AISI 1015) and plasticine material The model test results are compared with the simulation results and shows good agreement. The proper forging process with least forming energy can be resulted in $25^{\circ}$ of extrusion semi-die angle.

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Hysteretic Behavior of RHS Columns Under Random Cyclic Loading Considering Local Buckling

  • Yamada, Satoshi;Ishida, Takanori;Jiao, Yu
    • International journal of steel structures
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    • v.18 no.5
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    • pp.1761-1771
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    • 2018
  • In this paper, a hysteretic model of rectangular hollow section (RHS) columns that includes the deteriorating range caused by local buckling is proposed. The proposed model consists of the skeleton curve, the Bauschinger part that appears before reaching the maximum strength, the strength increasing part of the deteriorating range, and the unloading part. Of these, the skeleton curve, including the deterioration range caused by local buckling, which is considered to be equivalent to the load-deformation relationship under monotonic loading, is obtained through an analytical method. Bi-linear hysteretic models based on experimental results are applied to the Bauschinger part and the strength increasing part. The elastic stiffness is applied to the unloading part. The proposed model is verified by comparing with experimental results of RHS columns under monotonic and cyclic loading.