7 research outputs found
디사이클로펜타디엔 수지를 이용한 복합재료 액상성형공정 모델링 및 최적화
Get PDF학위논문 (박사)-- 서울대학교 대학원 : 기계설계전공, 2017. 2. 이우일.Demands for composite materials for civil applications in addition to military applications have been significantly increased. In the application for civil industries, it not only requires for a weight reduction but the efforts for achieving safety and a reduction of manufacturing cost has been sufficiently progressed. Dicyclopentadiene is a low viscosity resin which forms a poly-dicyclopentadiene rapidly through Ring opening metathesis polymerization (ROMP). This poly-dicyclopentadiene has outstanding properties of, low-temperature, water and impact resistances. Despite there are efforts for research developments of liquid molding technologies, dicyclopentadienes unique curing behavior and an unstable reaction in an atmospheric condition shows that the need for researches about an addition of reinforcements to the resin during the manufacturing process must be increased. The liquid molding apparatus which can be used with an addition of reinforcements was designed based upon the studies of the curing kinetics using the differential scanning calorimetry. Two different liquid molding methods have been developed depending on the resin viscosity, fiber volume fraction and the length. This apparatus was used for manufacturing samples where the mechanical properties were examined. Additionally, numerical analysis was performed in order to predict the manufacturing time depending on the resins viscosity and the fiber volume fraction.1. Introduction 1
1.1. Overview and problem description 2
1.2. Literature review 4
1.3. Research objective and scope 5
2. Experiment 6
2.1. Materials 7
2.2. Characterization of DCPD resin 7
2.2.1. Properties of DCPD monomer 7
2.2.2. Differential scanning calorimetry analysis 8
2.2.3. Three-point bending test 9
2.3. Processing of fiber reinforced composites 9
2.3.1. Reinforcement reaction injection molding (R-RIM) process 9
2.3.2. Structural reaction injection molding (S-RIM) process 10
2.3.3. Norbornene based silane treatment 11
2.4. Results and discussion 12
2.4.1. DSC and Three-point bending test results 12
2.4.2. Curing kinetics of DCPD resin 13
2.4.3. Mechanical properties of DCPD composites 13
3. Numerical analysis 18
3.1. Solution algorithms 19
3.1.1. Governing equations 19
3.1.2. Porous media flow 24
3.2. Modeling and conditions 26
3.3. Results of numerical simulation 26
3.3.1. Viscosity 26
3.3.2. Fiber volume fraction 27
3.3.3. Mold temperature 27
4. Summary and conclusion 29
References 32
Figures 35
Tables 73
요약(국문초록) 76Docto
Synchronousframe current control of multi-phase synchronous motor
No full text학위논문(박사)--서울대학교 대학원 :전기·컴퓨터공학부,2004.Docto
Development of highly active and durable bismuth oxide-based oxygen electrodes for reversible solid oxide cells at reduced temperature
No full textELECTROLYTE MATERIAL FOR SOLID OXIDE FUEL CELL, MANUFACTURING METHOD THEREOF, AND SOLID OXIDE FUEL CELL COMPRISING SAME
No full text본 발명의 일실시예는, 산화 비스무트에 어븀(Er), 이트륨(Y) 및 지르코늄(Zr)이 도핑된 것을 특징으로 하는, 고체산화물 연료전지용 전해질 소재, 이의 제조방법 및 이를 포함하는 전해질 및 연료전지를 제공한다. 본 발명에 따르면 높은 이온전도도를 가지며, 700℃ 이하의 온도에서 장시간 연료전지를 구동하여도 이온전도도의 저감이나 사면체 플로우라이트 구조로의 상변이가 발생하지 않아 내구성이 우수한 고체산화물 연료전지용 소재, 이의 제조방법 및 이를 포함하는 전해질 및 연료전지를 제공할 수 있다
