• 공업화학
• /
• 제23권5호
• /
• pp.433-439
• /
• 2012

본 연구에서는 도데실 글리시딜 에테르와 아미노에탄올을 반응시킨 후 디메틸 설페이트로 4급화시켜 분자 내에 2개의 라우릴기, 3개의 히드록실기를 가진 양이온 계면활성제 BHMAS (N,N-bis-(3'-n-dodecyloxy-2'-hydroxypropyl)-N-methyl-2-hydroxyethylammonium methyl sulfate)를 합성하였고, 생성물의 분자구조는 $^{1}H-NMR$, FT-IR 등의 기기분석을 통하여 확인하였다. 합성한 계면활성제의 CMC (critical micelle concentration)는 $9.12\;{\times}\;10^{-4}$ mol/L이며, CMC에서의 표면장력은 28.71 mN/m이었다. Maximum bubble pressure tensiometer를 사용하여 동적 표면장력을 측정한 결과, 공기와 수용액의 계면이 계면활성제 단분자에 의하여 포화되는 데 비교적 오랜 시간이 소요되었다. 1 wt% 계면활성제 수용액과 n-decane 사이의 계면장력은 0.045 mN/m이며, 평형에 도달하는 데 약 5 min의 시간이 소요되었다. 합성된 계면활성제의 흡착 특성이 매우 우수하였으며, 합성한 양이온 계면활성제가 섬유표면에 효과적으로 흡착되어 유연효과를 나타낼 수 있음을 확인하였다.

• 한국해안해양공학회지
• /
• 제10권2호
• /
• pp.64-72
• /
• 1998

해저자원개발에 사용되는 riser나 TLP의 인장각과 같은 세장해양구조물의 파랑 및 상단부유체의 운동에 대한 동적거동해석을 수행하였다. 구조부재의 유한요소모델을 사용한 수치해석기법을 개발하고 규칙파에 대한 시간영역해석을 수행하였다. 본 연구는 상단부유체의 수평 및 수직운동이 구조물의 횡방향거동에 미치는 영향을 분석하였으며, 특히 부유체 수직운동의 영향을 주로하여 패러미터연구를 수행하였다. 수심, 파랑조건 그리고 부유체운동 등 여러경우에 대한 구조물의 변의, 휨응력을 비교검토하였고, 이 해석을 통하여 부유체의 수직운동에 의한 시간변화 인장력으로 야기되는 불안정조건을 검토하였다. 예제해석결과, 부유체의 수평 및 수직운동의 상호작용으로 riser의 동적응답이 증폭되었다. TLP 인장각의 경우 부유체의 수직운동효과가 구조물의 거동에 상당히 크게 작용하는 것으로 나타났다.

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2004년도 학술대회지
• /
• pp.123-130
• /
• 2004

Ocean developments gradually move to deep-sea in the 21 century. A deep-sea unmanned underwater vehicle is one of important tools for ocean resource survey. A marine cable plays an important role for the safe operation of a deep-sea unmanned underwater vehicle. The first cable of a deep-sea unmanned underwater vehicle is excited by surface vessel motion and shows non-linear dynamic behaviors. A numerical method is necessary for analysing the dynamic behaviour of the first marine cable. In this study, a numerical program is estabilished based on a finite difference method. The program is appled to a 6000m long cable for a deep-sea unmanned underwater vehicle and shows good reasonable results.

• Journal of Welding and Joining
• /
• 제3권2호
• /
• pp.42-51
• /
• 1985

The dynamic fracture toughness, fracture characteristics, impact tension and tensile properties of Al-Mg-Si T5 alloy and Al-Zn-Mg T6 alloy respectively welded with filler metal of Alcan 4043 were investigated. The dynamic fracture toughness values were obtained rapidly and simply for the specimen of small size by using instrumented Chirpy impact testing machine. the testing temperatures of the specimen were a range of room temperature and-196.deg. C. The results obtained in this experiment are summarized as follows. With decreasing the testing temperatures, dynamic tensile stress and fracture load were increased, on the other hand the deflection and impact value showed decreasing tendency in order of base metal>HAZ>weld. Changes of total absorbed energy were more influenced by the crack propagation energy than the crack initiation energy. At the low temperatures, the unstable rapid fracture representing the crack propagation appeared for the specimens of Charpy press side notched in Al-Zn-Mg alloy, but it was difficult to obtain the unstable rapid fracture in Al-Mg-Si alloy. Because of the development of plastic zone at the notch root, it was difficult to obtain thevalid $K_{1d}$ value in Al-Mg-Si alloy. Therefore the fatigue cracked specimens were effective in both Al-Mg-Si and Al-Zn-Mg alloys. With decreasing the impact testing temperatures, specimens underwent a transition from dimple-type transgranular fracture to lamella surface-type intergranular fracture because of the precipitate at the grain boundaries, impurities and crystal structure of the precipitates.s.

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2004년도 학술대회지
• /
• pp.198-203
• /
• 2004

Ocean developments gradually move to deep-sea in the 21 century. A deep-sea unmanned underwater vehicle is one of important tools for ocean resource survey. A marine cable plays an important role for the safe operation and signal transmission of a deep-sea unmanned underwater vehicle. The first cable of a deep-sea unmanned underwater vehicle is excited by surface vessel motion and shows non-linear dynamic behaviors. A ROV launcher is also excited by the 1st cable motion. A numerical method is necessary for analysing the dynamic behaviour of the first marine cable and the ROV launcher. In this study, a numerival program is appled to a 6,000m long cable for a deep-sea unmanned underwater vehicle to shaw shows the dynamic behaviour of the cable and the ROV launcher under combined excitations.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2001년도 춘계학술대회 논문집
• /
• pp.231-234
• /
• 2001

Shearing, including blanking, trimming, piercing, etc, is one of the most frequently used processes in sheet metal manufacturing. In this paper, an individual set of tooling with an in-die sensor was designed and precisely fabricated to carry out the experiment for the shearing process investigation. Through various experiments, it has been examined the influence of process parameters such as clearance, edge material properties and pad configuration. Since the tension between the part and the scrap increases when the clearance increases, the clearance should be selected properly in order to reduce the burr height. Also removal of the lower pad makes the sheared surface worse and the shearing system unstable. The shearing force increases when the clearance decreases and the friction of the tooling material decreases. Dynamic reaction force is also important to obtain the fine sheared surfaces.

• 한국지반환경공학회 논문집
• /
• 제13권11호
• /
• pp.27-35
• /
• 2012

암반의 불연속면은 암반의 역학적 거동에 영향을 미치는 중요한 요소 중 하나이다. 편마암으로 이루어진 비탈면은 광범위한 범위에서 변성작용을 받아 형성되는 편마암생성과정과 엽리가 존재하는 이방성 구조 때문에 지질구조가 복잡하다. 본 연구대상 지역의 경우 절취공사 이전에 실시된 시추조사에서는 양호한 암반으로 조사되었으나, 약 20m 이상의 대절취공사를 수행하는 중인장균열이 약 170m 구간에 걸쳐 발생하였다. 인장균열 원인분석을 위하여 지표지질조사, 시추조사, 전기비저항탐사, 시추공영상촬영 등을 실시하였다. 전기비저항탐사와 지표지질조사를 통하여 광역에 걸친 단층대의 규모를 추정할 수 있었고, 종합분석한 결과 대규모의 단층활면 및 단층점토가 발견되었다.

• 한국해양공학회지
• /
• 제19권3호
• /
• pp.31-38
• /
• 2005

Ocean developments gradually move to deep-sea in the 21 century. A deep-sea unmanned underwater vehicle is one of important tools for ocean resource survey. A marine cable plays an important role for the safe operation and signal transmission of a deep-sea unmanned underwater vehicle. The umbilical cable of a deep-sea unmanned underwater vehicle is excited by surface vessel motion and shows non-linear dynamic behaviors. A numerical method is necessary for analysing the dynamic behavior of a marine cable. In this study, a numerical program is established based on a finite difference method. The program is appled to 6000m long cable for a deep-sea unmanned underwater vehicle and shows good reasonable results.

• 한국해양공학회지
• /
• 제18권4호
• /
• pp.15-22
• /
• 2004

Static and dynamic analyses of a very flexible and light riser, for upwelling the deep ocean water, is performed. In this numerical study, an implicit finite difference algorithm is employed for three-dimensional riser equations. Fluid non-linearity and bending stiffness are considered and solved, using the Newton-Raphson iteration. Maintaining the depth of end point of a flexible and light riser is very important for upwelling deep ocean water in a floating type development system. Weight is attached at the end point of the riser in order to maintain its intake depth. It is designed under the strong surface current and the configuration of the rise is predicted. In the dynamic analysis, the tension variation at the top point of the riser is presented. T e results of this study can contribute to the design of the development system in floating type for upwelling deep ocean water.

• 한국안전학회지
• /
• 제29권5호
• /
• pp.15-21
• /
• 2014

The aim of this work is conduct the study on light weight and structural performance improvement of the composite wind power blade. GFRP (Glass Fiber Reinforced Plastic) pre-empted by CFRP(Carbon Fiber Reinforced Plastic), the major material of wind power blade, was identified the superiority of mechanical performance through the tensile and fatigue test. SENT(Single Edge Notched Tension) specimen fracture test was conducted on the specimen that laminated together 2 ply CFRP with 4 ply GFRP through DIC(Digital Image Correlation) analysis. The SENT specimen thickness and $a_0/W$ ratio is 1.45 mm and 0.2, respectively. The fracture test accomplished with displacement control with 0.1 mm/min at the room temperature. The experimental apparatus used for the fracture test consisted of a 50kN universal dynamic tester and CCD camera connected to a personal computer (PC), which was used to record images of the specimen surface. Following data acquisition, the images and load-displacements were transferred to the PC, on which the DIC software was implement. The experiment and DIC analysis results show that CFRP/GFRP laminated composite exhibits improvement of the strength, compared with that of the existing blade material. This study shows the result that the strength of CFRP rotor blade of wind turbine satisfies through the experimental and DIC method.