표제지
요약
ABSTRACT
목차
제1장 서론 12
1.1. 연구배경 12
1.2. 연구동향 13
1.3. 연구범위, 목적 및 구성 15
제2장 빙 재료 모델 16
2.1. 빙의 기계적 특성 및 가정 16
2.2. 선형 드라커-프라거 항복기준 17
2.3. 손상모델 20
2.4. 손상기반 침식모델 22
2.5. 유한요소모델 24
제3장 평탄빙-구조물 상호작용 시뮬레이션 28
3.1. 평탄빙의 파단 28
3.2. 부력 모델 29
3.3. 항력 모델 30
3.4. 거시적 압괴 파단 모델 31
3.5. 유한요소모델 33
3.5.1. 평탄빙 파단과정 36
3.5.2. 빙편크기분석 39
3.5.3. 빙저항 40
제4장 평탄빙 조건에서의 쇄빙선에 작용하는 빙하중 46
4.1. 실험적방법을 이용한 빙저항 성분의 기여도 추정 47
4.2. 수치적방법의 빙저항 성분 기여도 추정 49
4.3. 본 연구의 빙 저항 성분 기여도 추정 방법 50
4.4. 유한요소모델 51
4.4.1. 파단패턴분석 54
4.4.2. 빙편크기분석 56
4.4.3. 전체 빙저항과 빙저항 성분의 기여도 58
4.4.4. 두 모델의 국부 빙하중 이력 비교 60
4.4.5. 하중의 극치평균과 극치 빈도수의 공간분포 63
제5장 쇄빙선의 누적피로손상도 66
5.1. 영향계수법(Influence coefficient method, ICM) 66
5.2. S-N선도 67
5.3. 본연구의 누적피로손상도 계산절차 68
5.3.1. Method1-1 응력의 극치를 이용한 누적피로손상도 69
5.3.2. Method1-2 응력의 극치분포를 이용한 누적 피로손상도 계산 69
5.3.3. Method2. 패널 별 하중의 극치분포를 이용한 보수적 누적피로손상도 계산 71
5.4. 유한요소모델 72
5.4.1. 정적해석모델 72
5.4.2. 직접해석모델 75
5.6. 패널 별 와이블 모수 80
5.7. 누적피로손상도 비교 82
제6장 결론 83
참고문헌 85
Table 1. Material properties of ice specimen 25
Table 2. Material properties of level ice 34
Table 3. Main particular of model ship 52
Table 4. Material properties of ice of target level ice resistance test 53
Table 5. Material properties of ice in present study 54
Table 6. Main particular of ship 74
Table 7. Material properties of level ice 77
Table 8. Result of damage with respect to speed 82
Table 9. Result of damage with respect to speed 83
Figure 1. YAMAL project 12
Figure 2. Stress-strain curve depended on strain rate 17
Figure 3. Failure surface of ice 17
Figure 4. Failure surface of present study 18
Figure 5. Damage model and effective stress 20
Figure 6. Flow chart for damage model applied to element erosion technique 22
Figure 7. Present damage model 23
Figure 8. Loading rig for 4-point bending test 24
Figure 9. Finite element model for 4-point bending 25
Figure 10. Damage evolution during 4-point bending test 27
Figure 11. Comparison of analysis results with experimental data 27
Figure 12. Out of plane bending failure of level ice 28
Figure 13. Surface forces acting on element faces before and after element erosion 30
Figure 14. Macroscopic crushing model 32
Figure 15. Pressure-penetration relationship 32
Figure 16. Fig.13 Geometric model 33
Figure 17. FE model 34
Figure 18. Continuous ice breaking process (V=0.791m/sec) 37
Figure 19. Fracture pattern during continuous breaking stage 38
Figure 20. Fracture pattern at bow area 39
Figure 21. Fracture pattern with respect to cone speed. 40
Figure 22. Global ice load and average ice load time histories with respect to cone speed. 42
Figure 23. Zoomed-in view of global ice load time histories with respect to cone speed. 44
Figure 24. Comparison of global mean ice loads between numerical analysis and experimental data. 45
Figure 25. Identification of ice resistance components (HSVA) 46
Figure 26. intect Level ice resistance test (fish-eye view) 48
Figure 27. Pre-sawn level ice resistance test (fish-eye view) 48
Figure 28. Comparative contribution of different load components versus interaction speed 49
Figure 29. Rubble removal model at side view 51
Figure 30. geometry of level ice resistance test model 52
Figure 31. FE Model 53
Figure 32. Fracture pattern at bow in present study 55
Figure 33. Fracture pattern at the side area in present study 56
Figure 34. Fracture pattern at the side area in model test and Full scale measurement by Zhou 56
Figure 35. Cusp size measurement in present study 57
Figure 36. PMF of cusp size with respect to speed 58
Figure 37. Average of cusp size between present study and target test 58
Figure 38. Comparsion of ice resistance with respect to speed between present study and experiement 59
Figure 39. Comparsion of contribution of ice resistance components with respect to speed between present study and experiement 60
Figure 40. Location of panels at the bow 61
Figure 41. comparison of local ice load at 5th panel[이미지참조] 62
Figure 42. Mean peak load and frequency of original model 64
Figure 43. Mean peak load and frequency of rubble removal model 65
Figure 44. Magnification Factor vs ratio of forced and natural frequency 66
Figure 45. S-N curve 67
Figure 46. Flow chart of fatigue damage calculation 68
Figure 47. Location of target point 73
Figure 48. Location of panels 73
Figure 49. The influence coefficient of the target point on each panel 74
Figure 50. Case interval =333m 75
Figure 51. Damage per unit distance vs interval at speed 1.0m/s 76
Figure 52. Stress time history and peak stress at target point during 0~330 sec 78
Figure 53. Histogram and weibul fitting curve of peak stress 79
Figure 54. Location of layer 80
Figure 55. Scale parameter of peak load 81
Figure 56. Scale parameter of peak stress 81
Figure 57. Shape parameter 82