• Geotechnical Engineering
• /
• v.8 no.2
• /
• pp.31-44
• /
• 1992

The probabilistic and statistical model is used to estimate the probability of liquefaction potential and pore water pressure build up due to earthquake in fully saturated sand deposit for each case of being structure(anisotropic) or not(isotropic). To execute this paper, dynamic shear strength parameters to show the relationship between shear strength and cyclic loading under isotropic or anisotropic condition in saturated sand deposit are presented. Using these parameters, the program which Predicts Pore water Pressure build up due to earthquake is developed. Using the 3-dimensional Random Field Model considering uncertainty of resistance and strength parameter, the program which computes the probability of liquefaction potential is developed. The developed program is applied to a case study, and then the result shows that the probability of liquefaction in isotropic condition is higher than in anisotropic condition. The ratio of pore water pressure tends to decrease as Kc increases.

• Magazine of the Korea Concrete Institute
• /
• v.26 no.1
• /
• pp.35-40
• /
• 2014

• Journal of Ocean Engineering and Technology
• /
• v.7 no.2
• /
• pp.162-172
• /
• 1993

In the present paper, the overall state of the arts of ice mechanics which is the most typical research topic of the artic engineering field was studied. And also, ice loads genrated by ice-structure interaction were estimated using numerical approach. The effects of viscous property of ice sheets to the ice load were investigated. The time dependent deformation behaviors of ice was modeled by visco-plastic problem using the finite element formalism. Constitutive model representing the material properties of ice was idealized by comblned rheological model with Maxwell and Voigt models. Numerical calculations for the bending and crushing behavior of ice sheet which are the most typical interaction modes between ice sheets and structures were carried out. The time dependent viscous behaviors of ice sheets interaction forces acting on structures were analyzed and the results were studied in detail.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.1
• /
• pp.154-161
• /
• 2001

A UBET analysis has been carried out to predict the forming load and the extruded length of forward and backward extrusion of hexagonal and trochoidal wrench colts. For the upper bound load and the average length of the extruded billets are determined by minimizing the total energy consumption rate which is a function of unknown velocities and parameters at each element. Experiments are carried out with antimony-lead billets at room temperature using hexagonal and trochoidal shaped punches. The theoretical predictions of the forming load and the extruded length are in good agreement with the experimetal results.

• Journal of the Korean Geotechnical Society
• /
• v.18 no.3
• /
• pp.73-85
• /
• 2002

This paper is focused on studying the undrained cyclic triaxial behavior of saturated Nak-dong River sand, using anisotropically consolidated specimens. A test of isotropically consolidated specimens was performed to compare the results of the anisotropically consolidated specimens. The cyclic shear stre3ngth of the sand under various combinations of initial static shear stress and relative density was considered. Failure was defined as a 5% double amplitude cyclic strain and a 5% residual axial strain for both reversal stress and no reversal stress conditions. Using this definition, the cyclic strength of the anisotropically consolidated specimens was affected by the initial static shear stress. For anisotropically consolidated Nak-dong River dense sand, the cyclic strength is greater than that of Toyolura silica sand but is smaller than that of Dogs Bay carbonate sand. By comparing the experimental and predictecl results, it was possible to predict the residual pore pressure of Nak-dong River sand using Hyodo's model with initial static shear stress subjected cyclic loading.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.19 no.4
• /
• pp.67-73
• /
• 2011

For loads analysis of airplane, applicable regulation should be determined. Then, loads conditions are prepared from the regulation. Modeling for aerodynamic, mass, and structure are performed. Panel method is usually adopted for aircraft loads analysis to obtain air loads. The ARGON which is a multidisciplinary fixed wing aircraft design software co-developed by the KARI and TsAGI are used for loads analysis. The ARGON can be utilized for flutter and stress analysis as well as for flight and ground loads analysis. In this paper, flight loads analysis for wing structural design of the regional aircraft at the conceptual design phase are performed with the ARGON. FAR 25 is used for the regulation for the load analysis. Shear force, bending moment and torsion diagrams for the wing and shear force and hinge moment for the aileron are presented.

• Computational Structural Engineering
• /
• v.7 no.3
• /
• pp.177-183
• /
• 1994

The purpose of this study is to develop the analytical method and to analyze the geometrically nonlinear behavior of suspension bridges. Two step algorithm is developed to analyze the initial profile under the deal load and the nonlinearity under the live load. Since the geometrically nonlinear effect is great comparing with the linear analysis, it should be considered in the analysis and design. The comparison between analysis and measurement shows that the new algorithm is effective.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.2 no.1
• /
• pp.81-88
• /
• 1998

과적차량의 통행에 의한 교량구조물의 손상도를 평가하는 방법의 개발이 매우 활발하다. 본 연구에서는 과거 15년동안 통행한 교통데이타를 분석하고, 이 데이타를 근거로 교량의 손상도를 분석한다. 차량의 분류는 4종으로 대표하여 차량하중을 분석하였으며 해석시에는 이를 대표하는 2종을 사용하였다. 3차원해석을 통하여 구한 영향면을 이용하여 부재력을 계산하고 이를 이용하여 등가응력범위를 구한다. 이 결과는 모형실험을 통하여 구한 피로결과와 비교하였다. 분석결과 설계하중을 초과하는 과적차량이 교량에 미치는 손상정도는 적은 통행빈도에도 불구하고 매우 큼을 알 수 있고, 이러한 실제교통량의 분석을 통한 교량의 손상평가방법은 과적차량에 의한 교량손상정도를 유용하게 평가할 수 있다.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.26 no.1
• /
• pp.39-46
• /
• 2010

To assess the stress distribution of implant prosthesis induced by intentional misfit using photoelastic model. Stress was measured at the surrounding bone after applying vertical load to the implant. Three implants were placed in each of three photoelastic resin blocks. No misfits were used for the control group, while for the experimental group $100{\mu}m$ misfit after cutting the crown was used. The photoelastic stress analysis was performed. In control group, stress concentration was not shown when the load was not applied, whereas stress concentration was shown only in the loaded part even when load was applied and the stress was distributed in anterior-posterior direction when applying a load in the middle. When intentional misfits were given, stress around the fixture was incurred when tightening the screw even if load was not applied. If the load was applied, stress was concentrated around the implants including areas where the load was applied. In particular, the prosthesis made of UCLA showed more stress concentration as compared with a conical abutment. In the UCLA case, concentration was shown from the apex following through the axis to the cervical area. Prosthesis with misfit makes the stress concentrated though the load was not applied and it induces even more severe stress concentration when the load was applied. This founding demonstrates the importance of the correct prosthesis production.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.3A
• /
• pp.211-219
• /
• 2010

The design concept of high speed railway bridges is applied to a method for increasing the stiffness of existing bridge structures considering the impact factor by a static load. Generally, the process of structural design would be relied upon an advanced foreign technology. However, the dynamic amplification factor (DAF) and dynamic capacity assessment of high speed railway bridges may be conducted essentially a detailed estimation because the resonance phenomenon is affected by the long length (380 m) and high speed (300 km/h) moving of a high speed railway (Korea Train eXpress: KTX). Therefore, this study will be examined the dynamic capacity of the typical PSC Box Girder high speed railway bridge efficiently, and offered the basic information for the reasonable structural design. For this, the static analysis is conducted considering the load line diagram of KTX based upon existing references. In addition, the KTX moving load is transformed into the time series load considering various analytical variables. The time history analysis is assessed reasonable using the transformed time series load. At that time, analytical variables for calculating the time series load are considered loading node distance, time increment and KTX velocity variation etc. The dynamic capacity of the PSC Box Girder high speed railway bridge is examined based upon the FE analysis result systematically. The structural safety is assessed quantitatively in accordance with the related regulation of the inside and outside of the country.