http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Lee, Younghun,Gwak, Min-cheol,Cho, Heaseong,Joo, Hyun Shig,Shin, Sang Joon,Yoh, Jack J.,Shin, Jae-Cheol American Institute of Aeronautics and Astronautics 2018 Journal of spacecraft and rockets Vol.55 No.4
<P>We develop a combined Lagrangian-Eulerian method for transient fluid-structure interaction problems. Based on the ghost fluid framework for improving interface tracking accuracy between a fluid (hot rocket exhaust plume) and a high strain rate deforming solid (rear cover of a vertical launch system), the numerical coupling between the two media ensures an accurate description of the flexible structure. A nine-node quadrilateral element based on total Lagrangian formulation is used, while the hydrodynamic finite difference method is used for the supersonic exhaust plume that forms a complex flow within the plenum. The Lagrangian, Eulerian, and fluid-structure interaction coupling methods are verified by ANSYS results and related theories. A two-dimensional simulation of the full vertical launch system operation mode is conducted. This requires an accurate reproduction of the complex flowfield generated by the rapid rear cover opening under a high-pressure plume during rocket launch. This fluid-structure interaction problem solution may be used for future design upgrades when a vertical launch system is exposed to unusually harsh interactive gas and structure conditions.</P>
임영훈(Younghun Lim),김형주(Hyung Joo Kim),양현채(Hyeon Chae Yang),고병옥(Byeong Ock Go),최지영(Ji Young Choi),장선화(Sun Hwa Jang) 과학기술정책연구원 2017 정책연구 Vol.- No.-
As a result of pursuing regional industrial policies based on balanced and specialized development, there is no contradiction in the positive aspects of the expansion of local industry and innovation bases. But others have questioned the effectiveness and validity of the policies. In the context of the demand for re-establishing regional industrial policies or re-establishing the direction, it is necessary to thoroughly examine and reflect on various points of view in order to prevent distortions in policy evaluation and lead to careful decisions. Therefore, this study analyzes the structure of regional technical knowledges represented by patents in a multifaceted way, especially related to the regional industrial policies. This is intended to escape from the old point of view to evaluate regional industrial policies with quantitative economic indicators such as sales, employment and production. This study utilizes patents as a representative indicator for observing regional industrial technology topography. Based on analyzing the linkage, transformation and network between IPC(International Patent Classification) and KSIC(Korean Standard Industrial Classification), This study examine the relationship between industrial technology topography and strategic industries in case regions. The case regions are Jeollabuk-do and Gangwon-do. The data utilized are registered patents from 2000 to 2016. Chapter 2 examines literature on regional innovation system, regional industrial policy and patent-based regional industrial technology topography. Chapter 3 outlines the process and status of regional industrial policies. Chapter 4 and 5, which correspond to the core analysis part of this study, deal with the analysis of three parts on the changing patterns of industrial technology topography in Jeollabuk-do and Gangwon-do, respectively. More specifically, three parts are as follows. ① The structure and connection characteristics of the regional technical knowledge structure. ② Major trends in regional technical knowledge structure change. ③ the characteristics of industrial linkages and element technology linkages. Chapter 6 diagnose the relevance between regional technical knowledge bases and strategic industries. Finally, chapter 7 suggests comprehensive conclusions and policy implications. This study found that it is reasonable to accept that regional industrial policies in Korea for about 20 years have produced positive effects on regional industrial and innovative capacity establishment. Of course, it can be denied from the old point of view to evaluate regional industrial policies with quantitative economic indicators. But we have to examine the meaning, value and effects of regional industrial policies in various aspects, before evaluating, re-establishing, sustaining or abolishing the policies. In this sense, the study presents a qualitative analysis and policy implications from different angle different from the major economic or quantitative ones. In short, despite the limitation of study that should be improved in the future, this study provides some meaningful results and suggestions for the regional industrial policy. Of course, this study is a pilot one to evaluate, diagnose, discuss the meaning, value, effects of existing regional industrial policy in Korea. The key contribution is the positioning of strategic industries of case regions to a two-dimensional matrix, consisted of an industrial policy aspect axis and a science & technology policy aspect axis. As a result, we suggest that strategic directions of regional industrial policy should be different according to the characteristics of strategic industries, regional industrial bases and technical knowledge ones. To obtain more effective conclusions, subsequent studies are needed.
유체-고체 연성 해석 기법을 통한 수직발사대 후방 덮개의 거동 해석
이영헌(Younghun Lee),곽민철(Min-cheol Gwak),조해성(Haeseong Cho),주현식(Hyun Shig Joo),신상준(Sang Joon Shin),여재익(Jai-ick Yoh) 한국추진공학회 2016 한국추진공학회 학술대회논문집 Vol.2016 No.12
수직 발사대는 발사체에서 나오는 화염에 의하여 구조체의 손상이 일어날 수 있고 특히 후방덮개는 화염에 의하여 직접적으로 변형이 일어나므로 이를 해석하기 위해서는 유체-고체 연성해석 기법을 필요로 한다. 본 연구에서 발사체의 화염은 Eulerian 기법을 이용하여 해석하였고, 발사대의 후방 덮개는 Lagrangian 기법을 사용하여 해석하였다. 서로 다른 두 물질간의 경계면은 레벨을 통하여 추적을 하였고 경계면에서의 경계값은 가상유체 기법을 활용하여 결정하였다. 본 논문에서는 후방 덮개의 변형 형상에 따라 달라지는 유동의 변화를 확인하였다. This paper presents a numerical analysis of behaviors of rear closer of vertical launch system under rocket plume based on fluid structure interaction analysis. The rocket plume loading is modeled by fully Eulerian method and elasto-plastic behavior of rear cover is calculated by total Lagrangian method based on a 9-node planar element. The interface motion and boundary conditions are described by a hybrid particle level-set method within the ghost fluid framework. We compare the fluid flow pattern between different rear closer models which are elast-plastic and rigid deformation.
유체-고체 연성 해석 기법을 통해 유체에 의한 고체의 탄소성 거동 해석 연구
이영헌(Younghun Lee),곽민철(Min-cheol Gwak),조해성(Haeseong Cho),주현식(HyunShig Joo),신상준(SangJoon Shin),여재익(Jai-ick Yoh) 한국항공우주학회 2016 韓國航空宇宙學會誌 Vol.44 No.11
본 연구에서는 발사체를 보관하고 사출하는 수직 발사대에서 발사체의 화염에 의해 변형되는 발사대 후방덮개의 응답을 유체-고체 연성해석 기법을 이용하여 해석하였다. 발사체의 화염은 Eulerian 기법을 이용하여 해석하였고, 탄소성 변형이 일어나는 후방 덮개는 9절점 유한 요소 기법을 사용하여 해석하였다. 유체와 고체 물질간의 경계면 추적은 레벨셋 기법을 사용하였고 경계값은 가상유체 기법을 이용하여 결정하였다. 각 해석 기법들은 이론값들을 통하여 검증되었고, 후방 덮개의 해석 결과는 후방 덮개가 변형되는 시간을 비교하였다. This paper presents numerical investigation on behaviors of the rear cover in the vertical launcher under rocket plume loading by using fluid-structure interaction analysis. The rocket plume loading is modeled by the fully Eulerian method and elasto-plastic behavior of the rear cover is predicted by the total Lagrangian method based on a 9-node planar element. The interface motion and boundary conditions are described by a hybrid particle level-set method within the ghost fluid framework. The present results will be compared with the experimental data in the future.
유체-고체 연성 해석 기법을 통한 수직발사대 후방 덮개의 거동 해석
이영헌(Younghun Lee),곽민철(Min-cheol Gwak),조해성(Haeseong Cho),주현식(Hyun Shig Joo),신상준(Sang Joon Shin),여재익(Jai-ick Yoh) 한국추진공학회 2017 한국추진공학회 학술대회논문집 Vol.2017 No.5
수직 발사대는 발사체에서 나오는 화염에 의하여 구조체의 손상이 일어날 수 있고 특히 후방덮개는 화염에 의하여 직접적으로 변형이 일어나므로 이를 해석하기 위해서는 유체-고체 연성해석 기법을 필요로 한다. 본 연구에서 발사체의 화염은 Eulerian 기법을 이용하여 해석하였고, 발사대의 후방덮개는 Lagrangian 기법을 사용하여 해석하였다. 서로 다른 두 물질간의 경계면은 레벨을 통하여 추적을 하였고 경계면에서의 경계값은 가상유체 기법을 활용하여 결정하였다. 본 논문에서는 후방 덮개의 변형 형상에 따라 달라지는 유동의 변화를 확인하였다. This paper presents a numerical analysis of behaviors of rear closer of vertical launch system under rocket plume based on fluid structure interaction analysis. The rocket plume loading is modeled by fully Eulerian method and elasto-plastic behavior of rear cover is calculated by total Lagrangian method based on a 9-node planar element. The interface motion and boundary conditions are described by a hybrid particle level-set method within the ghost fluid framework. We compare the fluid flow pattern between different rear closer models which are elast-plastic and rigid deformation.