• International Journal of Highway Engineering
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• v.4 no.3 s.13
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• pp.1-13
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• 2002

Design methods for new flexible pavements and overlays are in the transition from empirical to mechanistic approach, and many state highway agencies trend to move toward the adoption and use of mechanistic-empirical (M-E) design in new constructions and rehabilitations of flexible pavements. Hence, the Michigan Department of Transportation (MDOT) decided to develop a M-E flexible pavement design procedure, in which major pavement distresses such as fatigue cracking and rutting are employed as indicators of the serviceability of a flexible pavement. The main concept of the developed design procedure is that a designed pavement that is supposed to carry a certain number of traffic must satisfy designated thresholds of rut depths and fatigue lives during a service period. For the M-E design procedure, transfer functions were developed to predict rut-depths and fatigue lives. These functions related the pavement responses to pavement performance. For validation, three current new flexible pavement design cases were obtained from the MDOT. In these cases, asphalt concrete (AC) layer thicknesses determined by the suggested M-E procedure compare favorably with those determined by the current MDOT design practice that is based on AASHTO design guide. This finding implies that the suggested Michigan M-E flexible pavement design procedure can provide a good opportunity to improve the current design practice.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.718-725
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• 2016

In this study, the plastic flow curve of commercially pure titanium sheet (CP Ti) actively used in the plate heat exchanger etc., was evaluated. The plastic flow curve known as hardening curve is a key factor needed in conducting finite element analyses (FEA) for the forming process of a sheet material. A hydraulic bulge test was performed on the CP Ti sheet and the strain in this test was measured using the DIC method and ARAMIS system. The measured true stress-true strain curve from the hydraulic bulge test (HBT) was compared with that from the tensile test. The measured true stress-true strain curve from the hydraulic bulge test showed stable plastic flow curve over the strain range of 0.7 which cannot be obtained in the case of the uniaxial tensile test. The measured true stress-true strain curve from the hydraulic bulge test can be fitted well by the hardening equation known as the Kim-Tuan model.

• 레미콘
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• no.10 s.73
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• pp.2-12
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• 2002

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1996.06a
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• pp.846-849
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• 1996

• Water for future
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• v.48 no.10
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• pp.51-62
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• 2015

• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.675-684
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• 2010

The reinforced concrete members are designed to fail in flexural to lead ductile fracture. In the building structures, the failure is typically imposed on beams to prevent damages in columns. However, progression of plastic collapse mechanism may ultimately develop, a plastic hinge at the bottem end of the first floor column, which then can be subjected to shear or bond finally due to large axial force and small shear span-to-depth ratio. In this study, 10 RC column specimens failed in shear after flexural yielding was investigated to determine the factors affecting the plastic hinge length. The findings of this study showed that the most effective factor affecting the plastic hinge length was an axial force. As an axial force increase, an axial strain and a ductility ratio were decreased obviously. The test also shows the observed plastic hinge length was about 0.8~1.2d and the this result has difference compared with forward research.

• Journal of Korean Association for Spatial Structures
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• v.7 no.6
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• pp.69-74
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• 2007

Recently, to improve performance and strength of circular steel columns, application of concrete-filled steel tube(CFT) type are gradually increased. To accurately predict the plastic design of concrete-filled steel tube columns, a plasticity model is required which can be describe large deformation behavior of concretes and steels. In this study, elastic-plastic large deformation analysis is developed by using the plasticity model of structural steels, and accurate and validity of the developed program is verified by comparing between the experiment and the analysis for concrete-filled steel tube column. In concrete-filled steel tube columns, influence of initial deflection on ultimate strength behavior is investigated by using developed program.

• Journal of the Korean Institute of Gas
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• v.9 no.4 s.29
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• pp.1-5
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• 2005

An investigation was made on the fatigue characteristics of type 304 stainless steel membrane manufactured by plastic working. To investigate the effect of plastic deformation, tests were performed with 5 types of specimens having different amount of plastic deformation. Fatigue tests were executed under both room and LNG temperatures $(-162^{\circ}C)$. All the test results were compared with the fatigue data provided by RPIS (Recommended Practice for Inground LNG Storage Tank). On the basis of these results, it was confirmed that RPIS's design fatigue curve could be applied to evaluate fatigue life of KOGAS membrane manufactured by pressing.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.3
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• pp.453-458
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• 1992

본 연구에서는 유한요소법에 바탕을 둔 최적공정설계법을 이용하여 압출 금형 형상의 최적설계를 실시하였다.설계의 결과를 참고문헌에서 발췌한 이론해와 비교 하였으며, 축대칭 압출공정에서 압하율, 마찰, 재료특성 등이 금형의 최적형상에 미치 는 영향에 대하여 조사하였다.

• Transactions of Materials Processing
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• v.10 no.4
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• pp.294-301
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• 2001

The sensitivity method has been applied to find perform shape that results in the desired shape after foring. As a 2D example, initial shape of specimen for the cylinder shape without barrelling after forging has been found. The method is then applied to various shapes of 3D free forging and initial shapes of the corresponding specimens after forging have been found successfully The sensitivity method is proven to be an effective and accurate tool for the preform design.