• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.4
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• pp.375-382
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• 2008

The particular integral formulation for two(2D) and three(3D) dimensional inelastic transient dynamic stress analysis is presented. The elastostatic equation is used for the complementary solution. Using the concept of global shape function, the particular integrals for displacement and traction rates are obtained to approximate acceleration of the inhomogeneous equation. The Houbolt time integration scheme is used for the time-marching process. The Newton-Raphson algorithm for plastic multiplier is used to solve the system equation. Numerical results of four example problems are given to demonstrate the validity and accuracy of the present formulation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.34-39
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• 2005

In this study, 3-D nozzle shape and the shape of nozzle at exit plane were adopted as design parameter of 3-D supersonic nozzle and numerical analyses for these parameters have been performed to investigate the flow and performance characteristics for design parameters of the turbine. Firstly, comparing results for nozzle shape, rectangular nozzle had less total pressure loss occurred in axial gap and more power by 1.5% than circular nozzle did. Next, comparing the results for the shape of nozzle at exit plane, it is found that the performance of partial admission turbine was largely depended upon the gap between nozzle wall at exit plane and the hub / tip of rotor blade and the length between nozzles.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.1
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• pp.67-74
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• 1999

본 문에서는 선체 중앙부의 유한요소 모델링과 진동해석이 수행되었다. 횡부재와 종통부재가 만나 3차원적으로 연결되어 있는 선체구조는 복잡한 구조적 특성 때문에 모델링에 많은 노력이 필요하다. 선수, 선미부에 비해 비교적 부재간의 접속이 간단한 중앙평행부의 진동해석과 같은 경우에는 모델링 기법을 개발해 사용할 수도 있다. 중앙부 횡부재와 종통부재가 만나는 부분의 접속성과 형상표현을 위해 keypoint, super element(SE) 개념을 도입하였고 형성된 SE 들을 isoparametric mapping 기법을 접속된 3차원 부재용으로 개선하여 유한요소로 분할하였다. 진동해석용으로 형성된 선체중앙부 요소망을 ANSYS로 가시화하였고 자유진동해석을 수행하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2B
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• pp.175-185
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• 2011

This study investigates tsunami force acting on a group of onshore structures numerically by using three-dimensional one-field model for immiscible multi-phase flows, which is based on Navier-Stokes solver. In particular, we studied on the characteristics of tsunami with respect to the arrangement of onshore structures and the distance from seawall trough numerical experiments. For validation of the numerical method used in this study to calculate tsunami force, numerical results for tsunami force on the structures in coastal area are compared with available experimental data. Furthermore, a detail study on the efficiency of the numerical method is performed for the estimation of tsunami force based on the hydrostatic and hydrodynamic methods in which the numerical results are used. The obtained results are compared to the previous experimental one and design criteria. Considering both experimental results and numerical analysis results, semi-empirical formula by regression analysis is proposed. As a result, it was confirmed that the numerical analysis is effective to estimate on tsunami force acting on onshore structures.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1003-1005
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• 2017

본 연구에서는 수치해석을 이용하여 Scarfed Nozzle의 플룸의 형태와 유동 특성을 분석하였다. 일반적인 추진기관의 노즐과 다르게 Scarfed Nozzle을 가지는 경우 축대칭의 형상을 가지지 않기 때문에 3차원 해석을 진행 하였다. Scarfed Nozzle의 플룸의 형태를 분석하기 위해 Canted Nozzle의 해석결과와 비교를 하여 연구를 수행하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4694-4699
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• 2013

In this paper, a high pressure cleaning machine in field was disassembled and measured in order to develop a highly improved pressure cleaner in performance and real configuration was modeled by using 3-D design program CATA V5. In addition, fluid analysis was conducted on the modeled high pressure cleaning machine by using ANSYS finite element analysis program and visualize the pressure changes of internal fluid flow was visualized. This result will be applied to a new designed high pressure cleaning machine in future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4191-4196
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• 2013

In this paper, structural analysis was made on two cases in order to develop free rotational method and rotational angle in LCD monitor. The configuration of LCD monitor in field was modeled by using 3-D design program CATIA V5 and structural analysis was done to the modeled LCD in order to obtain stress, strain and total deformation by using ANSYS finite element analysis program.

• Journal of Korean Association for Spatial Structures
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• v.9 no.1
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• pp.61-68
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• 2009

This paper is concerned with the investigation of the structural behavior of waffle structure. Parametric variation on waffle floor thickness, main beam depth and column sizes are imposed to study the effects on mode shapes and natural frequencies of waffle structures. Comparisons between FEM models using shell and 3D-solid elements have also been made. The analysis result has shown that the mode frequencies increase with i) increase in main beam depth at level 2 and ii) decrease in waffle slab thickness at level 3. Both 3D and 2D model shown similar mode shapes. Besides, there is a consistent difference in mode frequencies between 3D and 2D model ranging from 25% to 36%.

• Journal of Korean Society of Steel Construction
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• v.29 no.4
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• pp.261-268
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• 2017

The purpose of this study is to analyze the ultimate strength and behavior of triangular and rectangular frames in steel towers. Investigations of collapse mechanism including local and global failures of partial frame are carried out through finite element analysis and small scaled experiments. Ultimate strength and deformation are investigated in case of shape variations with change of the interior and exterior frames. The efficiency of rectangular frame saving sub-brace members are verified with comparisons of the ultimate strength of triangular frames.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.5
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• pp.567-573
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• 2010

In this study, we evaluated the structural integrity and weight of a rocket motor with a torispherical dome by size optimization. Size optimization was achieved by first-order and sub-problem methods, using the Ansys Parametric Design Language (APDL). For rapid design verification, a modified 2D axisymmetric finite-element model was used, and the bolt pre-tension load was expressed as function of the ratio of the cross-sectional area. The thickness of the dome and the cylindrical part of the rocket motor were selected as the design parameters. Our results showed that the weight and structural integrity of the rocket motor at the initial design stage could be determined more rapidly and accurately with the modified 2D axisymmetric finite-element model than with the 3D finite-element model; further, the weight of the rocket motor could be saved to maximum of 17.6% within safety limit.