• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.4
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• pp.14-26
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• 1989

This paper describes the method of statistical analysis and its programs for predicting the ship's powering performance. The equation for the wavemaking resistance coefficient is derived as the sectional area coefficients by using the wavemaking resistance theory and its regression coefficients are determined from the regression analysis of the model test results. The equations for the form factor, wake franction and thrust deduction fraction are derived by purely regression analysis of the principal dimensions, sectional area coefficients and model test results. The statistical analyses are performed using the various descriptive statistic and stepwise regression analysis techniques. The powering performance prognosis program is developed to cover the prediction of resistance coefficients, propulsive coefficients, propeller open-water efficiency and various scale effect corrections.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.2
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• pp.60-71
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• 2017

A trajectory analysis program is developed using a 3DOF trajectory model for the performance analysis of geostationary launch vehicles by system options. Launch trajectory and the performance of injection at GTO was estimated using this program for several propellant options, engine types, number of engines and the location of launch site. Results of the analysis presents that the possibility of mission accomplishment by several design options using domestic launch sites and the development direction of GEO launch vehicles.

• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.193-201
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• 2013

Propeller is an important component of Human Powered Aircraft (HPA) propulsion system. HPA uses large diameter low rotational speed propeller to get high propeller efficiency. The propeller was designed by HPA propeller designing program. The propeller pitch is adjustable by rotating the blade axis angle at ground. Performance of the propeller for various parameters are analysed by the same program used for design. Off-design condition performance was also checked including pilot power change and flight speed change. The propeller was manufactured in ultra-light structure using carbon composite material down to 950g. The propeller was ground tested on ironbird and installed on KARI HPA. Finally the HPA flew 291m with this propeller.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.5
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• pp.307-314
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• 2023

This study aims to evaluate the blast performance of shear and flexure failure modes of reinforced concrete columns using finite-element analyses. To accomplish this goal, finite-element models of flexure- and shear-governed columns were developed and validated using previous experimental results. A blast simulation model was developed using a coupling-modeling method, and the modeling method was applied to the validated-column models. Blast responses were obtained for various blast loading scenarios, and the blast performance was determined using limits based on ductility and axial loading capacity.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.404-407
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• 2010

본 논문에서는 비선형 동적 해석 프로그램인 AUTODYN을 이용해 기둥의 단면 형상의 변화에 따른 폭발 하중의 영향을 분석하였다. 먼저 폭발하중 산정의 타당성을 확인하기 위해 AUTODYN을 이용한 예제해석을 수행하였으며, 폭발하중에 의한 영향을 가장 효율적으로 확인할 수 있는 인자인 압력을 비교하였다. 이를 토대로 기둥 형상에 따른 폭발 저항 성능을 평가하기 위해 같은 단면적과 높이를 갖는 정사각형과 원형 기둥을 모델링 한 후 TNT의 양에 따른 폭발전후의 부피를 비교하였다. 해석결과를 비교해보면 정사각형기둥이 원형기둥보다 폭발에 대한 손상정도는 더 크지만 기둥이 절단되지 않도록 하는 저항성능이 더 우수한 것을 확인할 수 있었다. 비록 철근의 영향을 고려하지 않았지만, 이와 같은 결과를 통해 TNT의 양에 따른 기본적인 폭발거동과 대테러 설계를 위한 기둥 단면 선택시 기초적인 자료로 활용가능 할 것으로 사료된다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.4
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• pp.133-140
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• 2008

The design method of the reinforced concrete structures is converting from the current limit state design method to the reliability based design method and active studies have been done in the US, Europe, and Japan etc. Performance based design method is considering lots of uncertainty of current design provision rationally and make sure that structure have a reliable reliability and safety. The main area of these studies is to secure the non-linear analysis technology with high reliability. The data for reinforced concrete columns tested by many researchers are used to verify the applicability of the nonlinear finite element analysis program (RCAHEST, Reinforced Concrete Analysis in Higher Evaluation System Technology). A comparison is made between analysis and test, calculated safety factor based on reliability theories to applies to analysis result.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.5
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• pp.37-43
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• 2003

Parallel computing method is widely used in the computational fluid dynamics for efficient numerical analysis. Nowadays, low cost Linux cluster computers substitute for traditional supercomputers with parallel computing shcemes. The performance of nemerical solvers on an Linux cluster computer is highly dependent not on the performance of processors but on the performance of network devices in the cluster system. In this paper, we investigated the effects of the network devices such as Myrinet2000, gigabit ethernet, and fast ethernet on the performance of the cluster system by using some benchmark programs such as Netpipe, LINPACK, NAS NPB, and MPINS2D Navier-Stokes solvers. Finally, upon this investigation, we will suggest the method for building high performance low cost Linux cluster system in the computational fluid dynamics analysis.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.263-267
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• 2008

In this work the realistic install performance analysis of a helicopter was performed together with power extraction enabling to operate auxiliary system as well as intake pressure loss, loss due to bleed air, etc. which must be considered in practical propulsion system's performance modelling to be installed to the airframe. The pressure loss occurring in intake was estimated from the intake performance map with relationships of Mach Number and pressure loss. In order to evaluate the proposed installed performance model, the experimental data for comparison must be needed when mounted in propulsion system. However because of lack of accessibility to such real data at the moment, the alternative way was made through comparison that the analysis results by the proposed model were compared with a wellknown commercial program GASTURB's analysis results. The validity of the proposed installed performance model was consequently confirmed because its average deferences from the GASTURB's results were within 0.5%.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.1
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• pp.51-56
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• 2008

In this work the realistic install performance analysis of a helicopter was performed together with power extraction enabling to operate auxiliary system as well as intake pressure loss, loss due to bleed air, etc. which must be considered in practical propulsion system's performance modelling to be installed to the airframe. The pressure loss occurring in intake was estimated from the intake performance map with relationships of Mach Number and pressure loss. In order to evaluate the proposed installed performance model, the experimental data for comparison must be needed when mounted in propulsion system. However because of lack of accessibility to such real data at the moment, the alternative way was made through comparison that the analysis results by the proposed model were compared with a wellknown commercial program GASTURB's analysis results. The validity of the proposed installed performance model was consequently confirmed because its average deferences from the GASTURB's results were within 0.5%.

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.69-70
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• 2008

본 논문은 광학 탑재체 성능의 MTF 예측에 있어, 광학 해석 프로그램인 ZEMAX와 MATLAB으로 구현된 기본 광학계 성능 해석 모델을 하나의 통합적인 툴 체계로 구현하였다. 그 결과 광학 탑재체 성능 해석에 광학계 설계, 제작/조립 및 궤도 상에서의 오차를 직접 반영할 수 있게 되었고 광학 탑재체의 초기 설계 단계에서 주요 설계인자를 도출하고, 지배적인 영향을 미치는 입력변수와 설계 요소들을 활용하여 광학 탑재체의 성능 예측을 수행할 수 있는 효율적이고 체계적인 틀을 개발하였다.