승객용 승강기의 재해예방대책

윤유성,Yun, Yu-Seong 대한산업안전협회 2002 안전기술 Vol.59 No.-

[0/90 0 ]s CFRP 복합재의 드릴작업손상과정 모니터링에 대한 AE의 적용

윤유성,권오헌,Yun, Yu-Seong,Gwon, O-Heon 대한기계학회 2000 大韓機械學會論文集A Vol.24 No.6

In recent years, CFRP composite materials have been increasingly used in various fields of engineering because of a high specific strength and stiffness properties. Drilling is one of the most impo rtant cutting processes that are generally carried out on CFRP materials owing to the need for the structural integration. However, delamination are often occurred as one of the drilling damages. Therefore, there are needs studying for the relationships between CFRP drilling and delamination in order to avoid low strength of the structures and inaccuracies of the integration. In this study, AE signals and thrust forces were used for the evaluations of the delamination from a drilling process in [0/900]s CFRP materials. And the drilling damage processes were observed and measured by a real time monitoring technique with a video camera. From the results, we found that the relationships between the delamination from drilling and AE characteristics and drill thrust forces for [0/900]s CFRP composites. Also, we proposed the monitoring method for a visual analysis of drilling damages.

유기성 폐기물 반응기 내부 교반 축 및 블레이드 건전성 평가

윤유성 ( Yu Seong Yun ) 한국안전학회 2017 한국안전학회지 Vol.32 No.2

Modern society has been experiencing by population growth and urbanization that bring, a change of eating habits which has occurred a various types of waste in a large amount. Even though these wastes are required an immediate treatment with difficulties unsanitary handling and existing waste treatment method are by incineration, fermentation, drying and etc. however a bad smell occurs after the treatment that need`s a lot of energy in processing organic wastes with high moisture contents and wasteful and inefficient problem. The strength assessment of the organic waste agitating vessel is required in terms of safety due to the differences of loading on the shaft that was treated by agitating the mixture of food waste. The damage of agitating axis is depended on steam pressure, temperature condition and the force moment that exerted by the food waste. Thus the strength assessment and stability evaluation are very important, especially to handle a hard waste. In this study the rotation capacity of agitation is about 5 tons considering general structural rolled steel pressure vessel strength and steam pressure. The purpose is to estimate the safety and strength evaluation for a agitator axis and impellers according to the rotating angle of the axis under the condition of the 3.2 ton capacity reactor.

섬유방향 변화에 따른 직물구조 CFRP 적층판의 균열진전 및 AE평가

윤유성(Yu-Seong Yun),권오헌(Oh-Heon Kwon) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.4

Crack propagation and AE characteristics of CFRP plain woven laminate composites are examined with acoustic sensor by AEDSP 32/16 board in PC system. AE signals are measured during the fracture behavior tests. The purpose of study is the estimation of the crack extension behavior effected between three kinds of fiber orientation for plain woven CFRP laminate composite and the relationship between AE characteristics and load-displacement curves and crack extension length.

제조업종의 산업재해 분석 연구

윤유성 ( Yu Seong Yun ),권오헌 ( Oh Heon Kwon ) 한국안전학회(구 한국산업안전학회) 2013 한국안전학회지 Vol.28 No.8

Workplace safety and health management in earnest was applied since 1981 when Occupational Safety and Health Actwas enacted. The accident rate of 3.98 in 1982 decreased to 0.65 in 2012 and in the case of death, the highest rate of deathsdecreased from 3.82 to 1.47 during the last 10 years, but the average accident rate of 0.75 has been at a standstill condition. Therefore it needs to understand the characteristics of a accident through the observation for the status of a recent business. Accident statistics for the analysis of industrial accidents in order to understand the recent trend ranges from 2002 to 2011 in 10years by KOSHA`s(Korea Occupational Safety & Health Agency) aggregated data. From the accident disaster statistics analysis byindustry, the manufacturing industry average shares 38.61% of accidents, and other industries, construction, telecommunicationstransportation warehouse, mining, and utility supply are 32.39%, 21.95%, 5.23% ,1.71% and 0.13%, respectively. Thus, themanufacturing sector by size and each type of accidents for the sub sector industries were analyzed in order to propose the basicdirection and to provide data of safety management for the manufacturing industry.

평직 CFRP 적층판의 층간파괴인성 및 AE 평가

윤유성(Yu-Seong Yun),곽정훈(Jung-Hoon Kwak),권오헌(Oh-Heon Kwon) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5

In recent years, the range of the composite materials' use for the making lightweight in the fighter, high-speed train, and car body have increased. Among them, fabric CFRP composites are being used as primary structural components in many applications because of their superior properties. However, the complexity of the fabric structure makes understanding of their failure behavior very difficult. Crack propagation of plain woven carbon fiber fabric laminate composites are examined by acoustic emission(AE) method. Thus, the relationship between AE signal and crack extension length are shown for several initial crack length. Also the interlaminar fracture toughness in terms of AE characteristics is discussed in viewpoint of crack propagation behavior.

직물구조 CFRP 적층판의 기계적 특성 및 균열진전에 미치는 AE거동

윤유성(Yu-Seong Yun),권오헌(Oh-Heon Kwon) 대한기계학회 2002 대한기계학회 기타 간행물 Vol.2002 No.11

CFRP/GFRP 적층복합재의 두께가혼합모드 균열거동과 AE에 미치는 영향

윤유성 ( Yu Seong Yun ),김다진솔 ( Da Jin Sol Kim ),권오헌 ( Oh Heon Kwon ) 한국안전학회(구 한국산업안전학회) 2014 한국안전학회지 Vol.29 No.6

Recently many efforts and researches have been done to cope with industrial facilities that require a low energy machines due to the gradual depletion of the natural resources. The fiber-reinforced composite materials in general have good properties and have the proper mechanical properties according to the change of the ply sequences and fiber distribution types. However, in the fiber-reinforced composite material, there are several problems, including fiber breaking, peeling, layer lamination, fiber cracking that can not be seen from the metallic material. Particularly, the fracture and delamination are likely to be affected by the thickness of the stacking laminates when the bi-material laminated structure is subjected to a load of the mixed mode. In this study, we investigated the effect of the thickness ratio of the difference in the CFRP/GFRP bi-material laminate composites by measuring the cracking behavior and the AE characteristics in a mixed mode loading, which may be generated in the actual structure. The results show that the thickness of the CFRP becomes more thick, the mode I energy release rate becomes a larger, and also the influence of mode I is greater than that of mode II. In addition, A Eamplitude which shows the level of the damage in the structure was obtained the more damage in the CFRP with the thin thickness.

복합모드 층간분리특성에 대한 PVC폼 코아 탄소섬유샌드위치 복합재의 실험적 해석

곽정훈,윤유성,권오헌,Kwak, Jung Hoon,Yun, Yu Seong,Kwon, Oh Heon 한국안전학회 2018 한국안전학회지 Vol.33 No.2

The light weight composite materials have been replacing in high performance structures. The object of this study is to examine the effects of the initial crack location about a delamination in a PVC foam cored sandwich composite that is used for the strength improvement of structures. The initial crack location and fiber laminates thickness were changed with several types. The MMB specimen was used for evaluating the fracture toughness and crack behaviors. The material used in the experiment is a commercial twill carbon prepreg in CFRP material and Airex in PVC foam core. Sandwich laminate composites are composed by PVC foam core layer between CFRP face sheets. The face sheets were fabricated as 2 types of 5 and 8 plies. The initial cracks were located in a PVC form core and the interface of upper CFRP sheet. From the results, the crack initiation was affected with the location of the initial crack inserted in the PVC foam core. Among them, the initial crack at 1/3 of the upper part of the PVC foam core was the most rapid progression. And the critical energy release rate was $0.40kJ/m^2$, which is the lowest value when the initial crack was inserted into the interface between a PVC foam core and CFRP laminated with 5 plies. Meanwhile, the highest value of $1.27kJ/m^2$ was obtained when the initial crack was located at the center line in case of the 8 plies.

사고유형 분석에 의한 승강기 및 에스컬레이터 재해예방

정옥남 ( Ok Nam Jeong ),윤유성 ( Yu Seong Yun ),권오헌 ( Oh Heon Kwon ) 한국안전학회(구 한국산업안전학회) 2016 한국안전학회지 Vol.31 No.4

The elevator is an essential part of the transportation means in modern society. It has become the convenient movement means of vertical and horizontal mobilities for vulnerable citizens including the disabled or elderly in skyscrapers and the multi-purposes facilities. After the 1990s, the number of newly installed elevators have increased because of the establishment of large scale public houses which need an increase of means of transportation. Thus, the safety accident in the elevator has been currently in an increasing trend as years passed by because that the elevator is always exposed to the risk of accident. Most of the elevator accidents occur in the escalator and moving walkway. This study investigated the current usage situations of users at multi-purpose shopping spaces, the sub way, and the airport about the escalator including moving walkway. Moreover the accident types were analyzed for the escalator based on 10 years of statistics. And the methods for the accident prevention were proposed on the equipment, management and user side.