• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.88-88
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• 2004

내압을 받는 압력관의 파괴는 원주방향의 응력이 주된 요인이므로, 압력관의 안전성을 평가를 위해서는 원주방향의 인장특성을 아는 것이 필요하다. 소형 압력관의 인장특성을 평가할 때, 정확한 원주방향의 인장특성을 알기 위해서는 관으로 가공된 후의 재료로 시험해야 하지만, 부피의 제약으로 인하여 원주방향으로의 표준 인장시험편을 제작하지 못하므로 가공하기 전의 재료의 물성치를 사용하고 있다. 이를 개선하고자 원주방향의 인장특성을 평가하기 위한 방법의 하나로 링 시험법(ring test)이 있다.(중략)

• Journal of Korea Game Society
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• v.14 no.6
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• pp.49-58
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• 2014

In particle-based fluid simulation, the yield stress is required for the deformation of the viscoelastic material like gel. von Mises's yield condition has been proposed to implement deformation of viscoelastic objects, but did not express the explosion. Furthermore, von Mises's yield condition is hard to approximate. We propose an ideal yield condition for viscoelastic object that reference from Tresca's yield condition. Unlike conventional particle-based simulation approximate the external power by the deformed length of the object, this paper is approximate the external power by area of the object. We check up that explosion was realistic when a viscoelastic object is compressed under the ideal yield condition.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.11-16
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• 2001

The polariscope to measure :he stress in lens was made up quarter-wave plate polarizer and we analyzed two components of light's wave $E_1$ and $E_2$ following the steps. It is clear that the principal-stress difference ${\sigma}_1-{\sigma}_2$ can be determined in 2-D model if fringe order N is measured each point in sample moreover. the optical axes of sample coincide with the principal-stress directions. The birefringence acted to a light wave and a phase retardation were in proportioned to the principal-stressed difference (${\sigma}_1-{\sigma}_2$) and the intensity of final light wave was proportioned to $sin^2({\Delta}/2)$, when ${\Delta}/2=n^{\pi}$ (n=0, 1, 2, ...) and the extinction occurs. As a experimental result, the extinction band shifted owing to a magnitude of lens' external stress.

• Journal of Navigation and Port Research
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• v.43 no.1
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• pp.9-15
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• 2019

Mooring bollards are the mandatory facility in ports for they are the objects used to fasten the ship to its position at the berth. All the mooring bollards were installed following suggested sizes, numbers, materials and shape of installation according to Port and Fishing Design Standards. However, Korea has no management standard for use of mooring bollards to safety in ship berthing. In this research, the installation standard for mooring bollards including the holding power applied to mooring bollards in berthing was studied. Also, the performance of mooring bollards for minimum safety guarantee in berthing based on research of various specification by their sizes was analyzed. The analysis on mooring bollards was examined by each power on mooring bollards from the applied force in berthing divided into horizontal and vertical direction in order to examine the performance of domestic mooring bollards, the limit force is calculated based on detailed specification research result. As a result, the working stress according to the towing force was found to be at least 150Mpa and it was evaluated to be 60% of the limit strength. Also, by comparing each forces, the appropriateness was examined and the specification of maximum capability calculated. This performance evaluation method based on detail specification of mooring bollards will be expected to be useful to examine the appropriateness of mooring bollards for various types of vessel in berthing and to develop maintenance and management standard through the performance change evaluation referring to mooring bollard detailed specification changes.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.1
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• pp.9-15
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• 2005

The polariscope to measure the microscopic stress in CR lens consists of light source polarizer, model, polarizer, CCD, computer, chrome conversion orderly and the principal-stressed difference, (${\sigma}_1-{\sigma}_2$) and the fringe order n were measured by analyzing two components of light wave $E_1$ and $E_2$ following each polarizer's steps. The two-dimensional model could be determined from the fact that the optical axes of sample concide with the principal-stress directions. The bi-refringence acted to a light wave and the phase retardation were in proportion to the principal-stressed difference(${\sigma}_1-{\sigma}_2$) and the intensity of final light wave was proportioned to $sin2({\Delta}/2)$ and when ${\Delta}/2=n{\pi}$ (n=0, 1, 2, ${\ldots}$) the extinction occurs. Photoelastic's image by microscopic stress could analyzed using chrome conversion, and the image showed clearly.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.138-147
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• 2011

The objective of this study which it sees direct shear stress and comparative analysis of flexural shear stress leads and it is a shear stress analysis which it follows in load direction of the structure which uses Perfobond Rib shear connectors. To analyze direct shear stress, five Perfobond Rib shear connect experiments were fabricated with five variables and conducted Push-out Tests. After experiments, mechanism of Perfobond Rib shear connector was examined and direct shear formula was proposed based on primary factors which influence direct shear stress. Also, for the analysis of flexural shear steel-concrete composite slab specimens were fabricated and static flexural test. Based on the static flexural test it analyzed the flexural behavior and the flexural shear stress it calculated. Direct shear stress and EN 1994-1-1 to lead and be calculated, it compared the flexural shear stress and it analyzed in about the shear resistance stress which it follows in load direction.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.429-433
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• 2005

본 연구에서는 레이놀즈응력모형(RSM: Reynolds Stress Model)을 이용하여 부분 식생된 개수로 흐름을 수치모의 하였다. 부분 식생된 개수로 흐름에서의 평균유속 및 난류구조를 수치모의 하고 기존의 실험결과와 비교하였다. 그 결과 개발된 모형이 식생된 개수로 흐름을 매우 잘 예측하는 것으로 나타났다. 특히, 이차흐름 벡터도를 수치모의 한 결과 식생구간과 비식생 구간에서 방향이 서로 다른 새로운 이차흐름 구조가 형성되는 것으로 나타났다. 또한 주흐름방향으로의 최대유속이 비식생 영역의 수면 아래에서 발생되고, 식생 및 비식생 영역의 경계면에서 난류량이 최대 값을 갖는 것을 확인하였다.

• Journal of Korean Society of Steel Construction
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• v.28 no.4
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• pp.293-301
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• 2016

Stability of cylindrical liquid storage tanks under seismic excitation could prevent catastrophic disaster of human life and economic loss. Domestic provisions on allowable compressive stress in tank walls to prohibit buckling failure are either incomplete or inconsistent, so foreign specifications such as API 650, BS EN 1998-4:2006 or New Zealand Standards are employed in stability design. In this study, response spectrum analyses are performed for plant tanks having different ratios of height to diameter or diameter to thickness to calculate hydrodynamic pressure on tank walls. Then nonlinear buckling analyses are conducted to estimate magnitude of buckling stress. By comparing analysis results with those from foreign design specifications, appropriate domestic design provisions are suggested.

• The Journal of the Petrological Society of Korea
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• v.21 no.2
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• pp.249-261
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• 2012

Olivine is a dominant mineral in the upper mantle and is elastically very anisotropic. When olivine is deformed under stress at high pressure and high temperature, lattice preferred orientation (LPO) is formed. It is known that the LPO of olivine is affected by water, stress, and pressure. In this paper, I reviewed the papers dealing with the effects of water, stress, and pressure on the LPO of olivine, summarized the papers on the LPOs of olivine in natural mantle rocks, and discussed its implications for seismic anisotropy in the upper mantle. In addition, I also described four types of LPOs of orthopyroxene recently found in natural spinel lherzolite.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.11
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• pp.1183-1189
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• 2015

This study focuses on the design of the tapered joints of a wind power turbine. The main variables of the tapered joint are the transmitted torque, shaft diameter, contact area of the tapered ring, and tightening torque of the bolts, which applies a compressive pressure from the hub to the shaft. The stress distribution of the taper fit was calculated under axisymmetric plane strain conditions because of the small taper angle. The axial displacement of the clamp can be calculated from the radial elastic deformation and the taper angle. The stress field of each ring is obtained from the cylinder stress equation. To verify the accuracy of the calculation, finite element (FE) analysis was performed, and the results of the calculation and FE analysis were compared. The hoop stress of the tapered surface showed a discrepancy of approximately 10, but the trends of the stress distributions of each component and the relative movement obtained by FE analysis were in good agreement with the analytical calculation results.