실린더에 존재하는 축방향 표면균열에 대한 공학적 J-적분식 (I) - 변형소성에 기초한 방법-

김진수,김윤재,박영재,김영진,Kim, Jin-Su,Kim, Yun-Jae,Park, Yeong-Jae,Kim, Yeong-Jin 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.8

This paper provides an engineering J estimation equation for cylinders with finite internal axial surfacecracks under internal pressure. The proposed equation is the J estimation equation based on deformation plasticity using Ramberg-Osgood (R-O) materials. Based on detailed 3-D FE results using deformation plasticity, plastic influence functions for fully plastic J components are tabulated for practically interesting ranges of the mean radius-to-thickness ratio, the crack depth-to-length ratio, the crack depth-to-thickness ratio. the strain hardening index for the R-O material, and the location along the semi-elliptical crack front. Based on tabilated plastic influence functions, the J estimation equation along the crack front is proposed and validated for R-O materials. Good agreements between the FE results and the proposed J estimation provide confidence in the use of the proposed method to elastic-plastic fracture mechanics of pressurized piping.

실린더에 존재하는 축방향 표면균열에 대한 공학적 J-적분식 (II) - 최적참조응력에 기초한 방법-

김진수,김윤재,김영진,Kim, Jin-Su,Kim, Yun-Jae,Kim, Young-Jin 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.11

This paper provides an reference stress based J estimation equation fur cylinders with finite internal axial surface cracks under internal pressure. In part 1, the J estimation equation based on deformation plasticity using Ramberg-Osgood (R-0) materials is proposed. In this paper, the developed CE/EPRI -type solutions ale then re-formulated based on the reference stress concept. Such a re-formulation provides a simpler equation for J. estimation are then further extended to combined internal pressure and bending. The proposed reference stress based J estimation equation is compared with elastic-plastic 3-D FE results using actual stress-strain data for a Type 304 stainless steel. Good agreement between the FE results and the proposed reference stress based J estimations provides confidence in the use of the proposed method to elastic -plastic fracture mechanics of pressurised piping.

이산사건 워게임 시뮬레이션을 위한 실시간 병렬 엔진의 설계 및 구현

김진수,김대석,김정국,류근호,Kim, Jin-Soo,Kim, Dae-Seog,Kim, Jung-Guk,Ryu, Keun-Ho 한국정보처리학회 2003 정보처리학회논문지 A Vol.10 No.2

군사용 워게임 시뮬레이션 모델들의 상호연동을 위해서는 국제표준연동(HLA : High Level Architecture)구조를 반드시 갖추어야하며 타 모델과 연동시 발생되는 시스템 오버헤드를 줄이기 위해서는 병렬 시뮬레이션 엔진 도입이 효과적이다. 그러나 기존 군사용 워게임 시뮬레이션 모델엔진의 이벤트 처리는 순차적 이벤트-드리븐 방식으로 처리하고 있다. 이는 병렬로 처리 시 글로벌 자료영역에 대한 동시참조등의 문제점들이 발생하기 때문이다. 아울러 기존 시뮬레이션 플랫폼으로 다중 CPU 시스템을 사용하여도 여러 개의 CPU를 다 활용하지 못하는 결과를 초래하고 있다. 따라서 이 논문에서는 군사용 워 게임 모델의 시스템 처리능력 향상과 글로벌 자료 영역에 대한 동시참조, 대외적인 시뮬레이션 시간처리, 장애 회복(Crash Recovery)시 병행 처리된 이벤트들의 순서를 보장 할 수 있는 객체모델에 기반한 병렬 시뮬레이션 엔진으로의 전환을 제안한다 이 전환된 병렬 시뮬레이션 엔진은 다중 CPU 시스템(SMP)상에서도 병렬 실행이 가능하도록 설계하고 구현하였다. Military wargame simulation models must support the HLA in order to facilitate interoperability with other simulations, and using parallel simulation engines offer efficiency in reducing system overhead generated by propelling interoperability. However, legacy military simulation model engines process events using sequential event-driven method. This is due to problems generated by parallel processing such as synchronous reference to global data domains. Additionally. using legacy simulation platforms result in insufficient utilization of multiple CPUs even if a multiple CPU system is under use. Therefore, in this paper, we propose conversing the simulation engine to an object model-based parallel simulation engine to ensure military wargame model's improved system processing capability, synchronous reference to global data domains, external simulation time processing, and the sequence of parallel-processed events during a crash recovery. The converted parallel simulation engine is designed and implemented to enable parallel execution on a multiple CPU system (SMP).

배관에 존재하는 원주방향 표면균열에 대한 파괴거동 해석 (I) -J-적분 예측식 -

김진수,김윤재,김영진,Kim, Jin-Su,Kim, Yun-Jae,Kim, Yeong-Jin 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.1

This paper provides the fully plastic J solutions for circumferential cracked pipes with inner, semi- elliptical surface cracks, subject to internal pressure and global bending. Solutions are given in the form of two different approaches, the GEF/EPRl approach and the reference stress approach. For the GE/EPRl approach, the plastic influence functions for fully plastic J are tabulated based on extensive 3-D FE calculations using the Ramberg-Osgood (R-O) materials, covering a wide range of pipe and crack geometries. The developed GEf/EPRl-type fully plastic J estimation equations are then re-formulated using the concept of the reference stress approach for wider applications. Based on the FE results, optimized reference load solutions for the definition of the reference stress are found for internal pressure and for global bending. Advantages of the reference stress based approach over the GE/EPRl-type approach are fully discussed. Validation of the proposed reference stress based J estimation equations will be given in Part II, based on 3-D elastic-plastic or elastic creep FE results using typical tensile properties of stainless steels and generalized creep- deformation behaviours.

PZT/Metal로 구성된 음향변환기의 음향특성에 관한 연구

김진수,강대하,김소정,김호기,이덕출,Kim, Jin-Soo,Kang, Dae-Ha,Kim, So-Jung,Kim, Ho-Gi,Lee, Deok-Chool 한국음향학회 1992 韓國音響學會誌 Vol.11 No.2

본 연구에서는 압전 특성이 우수한 PZT계 압전세라믹스를 원판상으로 박판화하여 금속 진동판에 부착시킨 PZT/Metal음향변환기를 제작하였다. 이 때 압전 세라믹스를 박판화하기 위해 'tape casting 방법‘을 사용했으며, 제작된 PZT/Metal 음향 변환기를 압전 부자, 압전 스피커등의 소자에 응용 시키기 위해 음향특성을 연구하였다. 연구 결과, 세라믹스의 압전 계수($d_{31}$)이 증가함에 따라 레벨(dB)이 -6dB에서 - 14dB로 증가된다. 음향 변환기의 직경비 ${\eta}$가 0.7-08이고, 두꺼비 (${\beta}$)가 1일 때 최적 음압 특성을 나타냈으며, 음압은 -15~-16dB정도이었다. In the study, the Acoustic transducer of a thin circular disc-type with PZT/Metal was manufactured. The 'tape casting method' was introduced to prepare the thin disc-type of piezoelectric ceramics. The acoustic characteristics of PZT/Metal acoustic transducer for piezoelectric buzzer and piezoelectric speaker etc. have been studied and analyzed. As a result, the sound pressure level (dB), in the range from -6dB to -14dB, increased with increasing the piezoelectric coeffeicient ($d_{31}$) of ceramics. The optimal conditions of the sound pressure characteristics of acoustic transducer were that the radius ratio(${\eta}$) of ceramics and metal plate is 0.7-0.8 and the thickness ratio(${\beta}$) is 1.0, and the value were -15~-165dB.

Pb(Sc1/2Nb1/2)O3-PbTiO3 계 세라믹스의 강유전성

김진수,김소정,김호기,이덕출 ( Jin Soo Kim,So Jung Kim,Ho Gi Kim,Deok Chool Lee ) 한국전기전자재료학회 1997 한국전기전자재료학회 추계학술대회논문집 Vol.1997 No.1

학교 이전적지의 적정활용 방안에 관한 연구 - 서울시 은평구 'A' 초등학교를 중심으로 -

김진수,김창신,김현호,동재욱,이화룡,Kim, Jin-Su,Kim, Chang-Shin,Kim, Hyoun-Ho,Dong, Jae-Wook,Lee, Hwa-Ryong 한국교육시설학회 2011 敎育施設 Vol.18 No.1

ent years, the change of urban function and the decrease in birth rate have given rise to merge, abolition and relocation of the existing schools. This study explores the possibilities for various land utilizations of relocated school sites, using the trial case of 'A' elementary school in Eun-pyeong gu, Seoul. 'A' elementary school has happened transfer plan due to the urban development project of the redevelopment area, Eun-pyeong gu in Seoul. Firstly, it studies the land use categories and the development methodologies of 7 relocated school sites happened in Seoul. In addition, it analyzes the land utilization after relocation, development principals, area, building usage and changes in land use regulation. Finally, it proposes the commercial exploitation of school site targeting 'A' elementary school site. Throughout the profit analysis, this study concludes that it is available to exploit the relocated school sites by the variety of development methodologies, especially in a metropolis like Seoul.

전방락킹, 후방락킹 운동 및 MET(Muscle Energy Techniques)를 이용한 Sway-back 자세 환자의 치험 3례

김진수,김종수,김정원,추원정,남항우,김창연,Kim, Jin-Soo,Kim, Jong-Su,Kim, Jung-Won,Choo, Won-Jung,Nam, Hang-Woo,Kim, Chang-Yeon 척추신경추나의학회 2012 척추신경추나의학회지 Vol.7 No.1

Sway-back 자세를 가진 환자 3례에 전방락킹, 후방락킹 운동 및 MET를 이용하여 치료한 결과 Whole spine X-ray(lateral)상의 척추만곡각도 및 NRS score의 호전을 확인하였다. 이에 저자는 본 증례를 보고하는 바이다. Objectives : The purpose of this study is to investigate the clinical application of Rocking forward, Rocking backward Exercise and MET(Muscle Energy Techniques) to three patients who had sway-back posture. Methods : Three patients diagnosed as sway-back posture, not have discogetic pain, were hospitalized Bu-Chun Jaseng hospital of Oriental Medicine about 20 days and they were treated by Rocking forward, Rocking backward Exercise and MET. To measure the outcome of the patients' improvement, we observed the X-ray of Whole spine and Numerical Rating Scale(NRS). Results : After being treated by Rocking forward, Rocking backward Exercise and MET, the patients' posture was significantly improved and the pain was reduced. The X-ray of Whole spine became almost normal and the improvement of patients' in the NRS score was detected. Conclusions : These results suggest that Rocking forward, Rocking backward Exercise and MET were effective treatment on patients who had sway-back posture.

서부 경남지역 토마토 농장에서의 위생 미생물의 분포

김진수,심원보,김지훈,김세리,정덕화,Kim Jin-Soo,Shim Won-Bo,Kim Ji-Hun,Kim Se-Ri,Chung Duck-Hwa 한국환경보건학회 2006 한국환경보건학회지 Vol.32 No.1

This study were conducted to investigate the microbial contamination level in 5 tomato farms in Western Gyeongnam. A total of 130 samples was examined for sanitary indicator bacteria, such as aerobic plate count (APC), coliforms, and Escherchia coli, and pathogenic bacteria such as E. coli O157:H7, Salmonella spp., Staphylococcus aureus, and Listeria monocytogenes. APC and coliform count ranged $0\~6.62\;and\;0\~4.52 log_{10}\;CFU/(ml,\;g,\;100\;cm^2,\;hand)$, respectively, and $32.5\%$ were contaminated with E. coli. Especially, most of the samples from employees are high as above $4.0\;log_{10}\;CFU/(ml,\;g,\;100\;cm^2,\;hand)$ in APC. S. aureus, detected at $10.7\%$, was found in employees' hands, irrigation water, and hydroponic solution. whereas E. coli $O157:H7$, Salmonella spp, and L. monocytogenes were not detected. These results will provide fundamental microbiological information for introduction of good agricultural practice (GAP)system in tomato farms.

PTS 사고하에서 J-Q해석법을 이용한 표면균열의 구속효과 고찰

김진수,최재붕,김윤재,김영진,Kim, Jin-Su,Choe, Jae-Bung,Kim, Yun-Jae,Kim, Yeong-Jin 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.1

In recent years, the integrity of reactor Pressure Vessel(RPV) under pressurized thermal shock (PTS) accident has been treated as one of the most critical issues. Under PTS condition, the combination of thermal and mechanical stress by steep temperature gradient and internal pressure causes considerably high tensile stress at the inside of RPV wall. As a result, cracks on inner surface of RPV may experience elastic-plastic behavior which can be characterized by J-integral. In such a case, however, J-integral may possibly lose its vapidity due to the constraint effect. The degree of constraint effect is influenced by the loading mode, crack geometry and material properties. In this paper, in order to investigate the effect of clad thickness and crack geometry on constraint effect, three dimensional finite element analyses were performed for various surface cracks. Total of 27 crack geometries were analyzed and results were presented by a two-parameter characterization based on the J-integral and the f-stress.