• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.03a
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• pp.21-27
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• 1998

An analysis for the prediction of wrinkling formation in curved sheets during metal froming is presented. We construct "Wrinkling Limit diagram"(WLD) which represent the combinations of the critical principal stresses for wrinkling formation in curved sheet elements subjected to biaxial plane stress. Here the scheme of plastic bifurcation theory for thin shells based on the Donnell-Mushtari-Vlasov shell theory is used. In this study, the effects of the material variables (yield stress, plastic hardening coefficient, plastic anisotropic parameter, and so on) and sheet geometry on the critical conditions for wrinkling is carried out numerically.merically.

• 연구논문집
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• s.26
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• pp.33-42
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• 1996

The transmission system of a washing machine which is called by the clutch is one of the most important components to preserve the performance. The clutch housing has a role to guard and mount the transmission system on the frame of the machine. The load which is applied on the clutch housing depends on the operating conditions. Nowadays the dehydration speed is higher and higher in order to improve the efficiency. In this study, the strains on the predicted weak positions were measured using the strain gage and its measuring equipment. The relationships between the dehydration speeds and the maximum principal strains were obtained. Finite element analysis is executed to acquire the effect of the dehydration speed on the stress of the clutch housing. The distributions of the equivalent stress and the maximum stresses under the various speeds, the various loading directions and the various thickness of the clutch housing were obtained.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.26-33
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• 2001

This paper compares conventional beam analyses with exact three dimensional plate analyses through numerical examples with plates under wind loads in order to study the disadvantages of conventional simplified beam analyses of wind-loaded structures, Bending moments and principal stresses from beam analyses are good agreements with those from plate analyses but torsional moments are not. And it is possible to get result forces which are variant along width directions from plate analyses but not from beam analyses due to constant distributions of result forces along width directions. Therefore exact three dimensional plate analyses are required in the analyses of wind-loaded structures instead of conventional simplified beam analyses.

• Earthquakes and Structures
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• v.6 no.5
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• pp.457-472
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• 2014

The paper presents the field investigations and seismic analyses of a historical masonry brick minaret damaged during October 23 (Erciş) and November 9 (Edremit), 2011 Van earthquakes in Turkey. Ulu Mosque Minaret located on Tebriz Kap1 Street in the city centre of Van, Turkey is selected for investigation. Two earthquakes hit the minaret within seventeen days, causing progressive damage. It was seen from the field investigations that the minaret was heavily damaged. To validate the field investigations, three dimensional finite element model of the minaret is constituted by ANSYS software using relievo drawings. Finite element model of the minaret is analyzed under the Van earthquake records to determine the seismic behavior. The displacements, maximum and minimum principal stresses and strains are obtained from the analyses and compared with field observations.

• Advances in Energy Research
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• v.3 no.1
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• pp.1-10
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• 2015

In the past sidetracking was the means to bypass a damaged zone or to correct the direction of a wellbore. Nowadays, this method is very common and useful in relocating the bottom of a wellbore in a more productive zone and consequently enhancing the production of a reservoir by saving a significant amount of time and money. In this paper, the stability of the bend area is assessed considering varied conditions of stress regime and sidetrack orientation. In general, the stress regime and the orientation of the principal stresses have negligible effect on the stability of the sidetrack compared to sidetrack inclination. On the other hand, the sidetrack deviation angle from the vertical main well plays the major role in the stability of the bend area.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.496-501
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• 2003

Reynolds averaged Wavier-Stokes simulations based on the Reynolds stress model was performed to investigated the effect of inlet flow angle on the distributions of the Reynolds stress tensor inside tip leakage vortex of a linear compressor cascade. Two different inlet flow angles ${\beta}=29.3^{\circ}$(design condition) and $36.5^{\circ}$(off-design condition) were considered. Stress tensor analysis, which transforms the Reynolds stress into the principal direction, was applied to show an anisotropy of the normal stresses. Whereas the anisotropy was highest in the region where the tip leakage vortex collides the suction side of the blade and tip leakage flow enters between blade tip of the pressure side and the endwall, it had the lowest value at the center of tip leakage vortex. It was also found that the magnitude of maximum shear stress at design condition was greater than that of off-design condition.

• Journal of the Korean Society for Precision Engineering
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• v.5 no.1
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• pp.71-77
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• 1988

This study applies dynamic deformation analysis to the rake face stress distribution of cemented carbide cut-off tools by turning, using a finite element method. The results are following: 1. The dynamic loaded state of a cut-off tool was very changeable for the first 0.6 seconds. Reaching the normal state, it became in active. 2. Chipping was influnced not only by the magnitude of stress but also by the abrupt change of tensile and compressive stresses. 3. The distribution chat of principal stress by dynamic load and the direction of resultant vector were almost constant regardless of load time.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.8
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• pp.2524-2539
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• 1996

A design process and an axisymmetric boundary integral equation method for precise structural analysis of the aircraft gas turbine rotor disk were developed. This axisymmetric boundary integral equation method for stress and steady-state thermal analysis was improved in solution accuracy by appling an implicit technique for Cauchy principal value evaluation, a subelement technique for weak singular integral evaluation and a double exponentical integral technoque for internal point solution near boundary surfaces. Stresses, temperatures, low cycle fatigue lifes and critical speeds for the turbine rotor disk of the thrust 1421 N class turbojet engine were analysed in a pratical calculation model problem.

• Structural Engineering and Mechanics
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• v.70 no.5
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• pp.563-570
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• 2019

To analyze the seismic reliability of concrete rectangular liquid storage structures (CRLSSs), assuming that the wall thickness and internal liquid depth of CRLSSs are random variables, calculation models of CRLSSs are established by using the Monte Carlo finite element method (FEM). The principal stresses of the over-ground and buried CRLSSs are calculated under three rare fortification intensities, and the failure probabilities of CRLSSs are obtained. The results show that the seismic reliability increases with the increase of wall thickness, whereas it decreases with the increase of liquid depth. Between the two random factors, the seismic reliability of CRLSSs is more sensitive to the change in wall thickness. Compared with the over-ground CRLSS, the buried CRLSS has better reliability.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.220-230
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• 1993

Photoelastic isochromatic fringes related to the difference of principal stresses have some bandwidth whose light intensities are not constant and asymmetrical in experimental images. Hence, it is difficult to measure fringe order accurately at a data point by visual observation. In this study, a method of fringe sharpening, which can extract shapened lines from both full-and half-order fringes by digital image processing, is developed. To test the method, various simple photelastic fringe patterns are simulated and their images are processed to yield sharpened lines. The method is then applied to general problems such as images of a circular disk compressed by diametrically concentrated loads and a circular cylinder sybject to internal pressure. The procedure is proved to be capable of extracting sharpened lines accurately from photoelastic isochromatic fringes.