• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2368-2373
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• 2012

In this research, finite element method was carried out to evaluate the defomation of pipe and surface displacement for backfill of underground ficility. Various conditions for analysis were employer, including two different pipes(PE and concrete pipe), two different excavation depth(60cm and 150cm) and width(1.5D and 2D), a regular sand backfill, and four different flowable backfills. The vertical deformation of 60 cm diameter for PE was measured three times more than that of 30 cm diameter. The measured deformations for regular backfill and four flowable backfills were 0.320mm, and 0.135mm to 0.155mm, respectively. It ratio was around 40%. In case of 30cm diameter of concrete pipe, the measured vertical defomation was around 0.004mm for all the backfill materials. In case of installation depth, the effect of flowable backfill for flexible pipe is better than for rigid pipe. There is little effect on the deformation of concrete pipe with regular sand backfill and flowable backfill.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1989.04a
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• pp.50-55
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• 1989

Piping systems are composed of pipes with various thickness, diameter and length. Accurate analysis of a piping system requires a complicated three dimensional finite element model and a computer system with large memory size, while simplified models result in system response prediction with deteriorated accuracy. An efficient analysis model for piping systems is proposed in this study. The proposed model is developed by introducing a joint model which accounts for the behavior of a pipe connection. Pipes are represented by beam elements and the effect of local deformation of pipe connections are replaced by joint element deformations. The proposed model which is as simple and efficient as a beam model can be used to obtain piping system response with accuracy close to that of a finite element model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1102-1106
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• 2008

It's necessary to invent a measure to deal with expected counter results when observing mechanical behaviors under the various operations and it can be done by measuring the stress and deformation characteristics of the Automotive Air-Conditioner Hose, which is a hose made up of a rubber hose, an aluminum sleeve and pipe. In this paper, characteristics of the stress and deformation characteristics of the Automotive Air-Conditioner Hose which plays an important role in circulation of refrigerant of an air conditioner in an automobile are analyzed using the finite element method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.622-626
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• 2005

The Residual stress is stress at the inside of materials after plastic deformation. Certainly, this residual stress have an effect on fatigue life. Therefore, it is very important that understanding residual stress at the inside of materials. But in case of U-shaped Pipe that it is dealt with a mailer in this paper, distribution of residual stress is very complicated and exactly become unknown caused by difficulty of measurement. Then, in this paper, we are evaluated residual stress at in the inside of materials by finite clement method program and verified validity by test.

• 한국도로학회:학술대회논문집
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• 2003.10a
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• pp.271-278
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• 2003

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.789-790
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• 2008

• Steel and Composite Structures
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• v.20 no.4
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• pp.931-950
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• 2016

Ratcheting deformation of pressurized Z2CND18.12N stainless steel $90^{\circ}$ elbow pipe with local wall thinning subjected to constant internal pressure and reversed bending was studied using finite element analysis. Chen-Jiao-Kim (CJK) kinematic hardening model, which was used to simulate ratcheting behavior of pressurized $90^{\circ}$ elbow pipe with local wall thinning at extrados, flanks and intrados, was implemented into finite element software ANSYS. The local wall thinning was located at extrados, flanks and intrados of $90^{\circ}$ elbow pipe, whose geometry was rectangular cross-section. The effect of depth, axial length and circumferential angle of local wall thinning at extrados, flanks and intrados on the ratcheting behaviors of $90^{\circ}$ elbow pipe were studied in this paper. Three-dimensional elastic-plastic analysis with Chen-Jiao-Kim (CJK) kinematic hardening model was carried out to evaluate structural ratcheting behaviors. The results indicated that ratcheting strain was generated mainly along the hoop direction, while axial ratcheting strain was relatively small.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.1
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• pp.113-118
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• 2010

A straight pipe is used after complicated bending work in a mechanical system. In this work process, the plastic deformation of the pipe produces residual stress in the pipe. This residual stress significantly affects the behavior of pipe fracture. For this reason, residual stress must be evaluated. Measuring the residual stress of a U-shaped pipe is difficult with existing destructive and nondestructive measurement methods. In this paper, the residual stress of a U-shaped aluminum pipe (99.7% pure aluminum) was evaluated from the Raman shift by Raman spectroscopy and FEM(Finite Element Method, FEM) analysis. The results of the stiffness test by FEM analysis are compared with those by experiments. The analyzed results of the Raman spectra showed a similar tendency with the results of the FEM analysis with respect to the residual stress distributions in U-shaped pipes. Also, the results of the bending tests showed resemblance to each other.

• Journal of Korean Society of Steel Construction
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• v.15 no.1
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• pp.33-40
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• 2003

There are two basic concepts about concerning the buckling analysis of a buried pipe. One concept considers the soil around the pipe asn elastic continuum mediaum. The other concept holds that the pipe is sup ported by an elastic spring, which replaces the effects of the surrounding soil (the Winkler model). Theise buckling analysis is based on plane analysis, without considering the corrugation effect and the length effect. This paper thus presents a parametric study using the Finite Element Method (FEM) for the Winker model and proposes a buckling strength formula after examining a 3D analysis considering the corrugation effect and the length effect, thatwhichhelp in estimating the critical buckling strength of such CSP

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.730-737
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• 2004

In this paper, in order to examine cyclic hehavior characteristics and safety of underground flexible pipes for electric cables subject to cyclic vehicle load, FEM analysis and cyclic soil box test were carried out. As results of the test, it was revealed that the vertical displacement of the test was larger than that of FEM analysis because thermal effect arising from power cables made reduction of rigidity of the pipe so that large deformation of the pipe induced by the heat occured. Moreover, it was shown that the final vertical displacement under about 0.4 million times of the cyclic load test was not satisfied with elastic allowable displacement of the pipe, and long term stability of the pipe was not stable since behavior characteristics of the pipe exists plastic strain range pasted clastic strain range.