표제지
국문 요약
Abstact
목차
제1장 서론 13
1.1. 연구배경 13
1.2. 연구동향 및 목표 15
제2장 수중폭발 (UNDEX) 16
2.1. 수중폭발 현상 (UNDEX phenomenon) 16
2.2. 수중폭발 하중 (UNDEX loading) 19
2.3. Geers-Hunter 모델 22
2.3.1. 충격파 단계 (Shock-wave phase) 22
2.3.2. 버블 진동 단계 (Oscillation phase) 23
제3장 수중폭발 시뮬레이션 (UNDEX simulation) 26
3.1. Plate 및 Fluid 모델 26
3.2. 음향 경계조건 (Acoustic Boundary conditions) 28
3.3. 캐비테이션 (Cavitation) 29
3.4. 입사파 및 버블 하중 정의 (Defining incident wave and bubble loading) 30
제4장 수중폭발 해석 결과 (Results and discussions) 32
4.1. 유효성 검증 (Validation) 32
4.2. Elastic-Plastic 모델 33
4.3. Equivalent shock factor 모델 38
4.3.1. SF=0.2 (R=7.5m, TNT mass=10.25kg) 39
4.3.2. SF=0.238 (R=7.5m, TNT mass=15.75kg) 41
4.3.3. SF=0.27 (R=7.5m, TNT mass=20.25kg) 43
4.4. Rate dependence 모델 45
4.4.1. SF=0.2 (R=5m, TNT mass=5kg) with rate dependence 46
4.4.2. SF=0.238 (R=5m, TNT mass=7kg) with rate dependence 48
4.4.3. SF=0.27 (R=5m, TNT mass=9kg) with rate dependence 50
4.5. Damping 모델 52
4.5.1. SF=0.2 (R=5m, TNT mass=5kg) with damping 53
4.5.2. SF=0.238 (R=5m, TNT mass=7kg) with damping 55
4.5.3. SF=0.27 (R=5m, TNT mass=9kg) with damping 57
제5장 결론 (Conclusions) 59
참고문헌 61
Table 1. Shock wave and gas bubble parameters 20
Table 2. Material properties for steel 27
Table 3. Charge properties for TNT 31
Table 4. Mass proprtional daming and Stiffness proportional damping by plates 52
Figure 1. USS Jackson(LCS-6) Shock Trial (2016) 14
Figure 2. USS Gerald R. Ford(CVN-78) Shock Trial (2021) 14
Figure 3. Gas bubble motion and pressure history 16
Figure 4. UNDEX energy distribution 18
Figure 5. Definition of shock factor 21
Figure 6. Calculated shock and bubble pressure time history(depth 30m, TNT mass 5kg) 25
Figure 7. Geometrical configurations of stiffened plates 26
Figure 8. FSI surface, free surface and outer surface in fluid model 27
Figure 9. Boundary conditions in the UNDEX event 29
Figure 10. Distribution of initial acoustic static pressure 30
Figure 11. Comparison of fluid model 32
Figure 12. Comparison of response between Fathallah et al.(2014) and Analysis model 32
Figure 13. Displacement of the center point of Elastic-Plastic model at SF=0.2 33
Figure 14. Contour plot equivalent plastic strain of Elastic-Plastic model at SF=0.2 34
Figure 15. Displacement of the center point of Elastic-Plastic model at SF=0.238 35
Figure 16. Displacement of the center point of Elastic-Plastic model at SF=0.27 35
Figure 17. Contour plot equivalent plastic strain of Elastic-Plastic model at SF=0.238 36
Figure 18. Contour plot equivalent plastic strain of Elastic-Plastic model at SF=0.27 37
Figure 19. Geometrical configurations of extended fluid model 38
Figure 20. Maximum displacement by SFs at Equivalent SF model 38
Figure 21. Displacement of the center point of Equivalent SF model at SF=0.20 39
Figure 22. Contour plot equivalent plastic strain of Equivalent SF model at SF=0.2 40
Figure 23. Displacement of the center point of Equivalent SF model at SF=0.238 41
Figure 24. Contour plot equivalent plastic strain of Equivalent SF model at SF=0.238 42
Figure 25. Displacement of the center point of Equivalent SF model at SF=0.27 43
Figure 26. Contour plot equivalent plastic strain of Equivalent SF model at SF=0.27 44
Figure 27. Maximum displacement by SFs at Rate dependence model 45
Figure 28. Displacement of the center point of Rate dependence model at SF=0.2 46
Figure 29. Contour plot equivalent plastic strain of Rate dependence model at SF=0.2 47
Figure 30. Displacement of the center point of Rate dependence model at SF=0.238 48
Figure 31. Contour plot equivalent plastic strain of Rate dependence model at SF=0.238 49
Figure 32. Displacement of the center point of Rate dependence model at SF=0.27 50
Figure 33. Contour plot equivalent plastic strain of Rate dependence model at SF=0.27 51
Figure 34. Displacement of the center point of Damping model at SF=0.2 53
Figure 35. Contour plot equivalent plastic strain of Damping model at SF=0.2 54
Figure 36. Displacement of the center point of Damping model at SF=0.238 55
Figure 37. Contour plot equivalent plastic strain of Damping model at SF=0.238 56
Figure 38. Displacement of the center point of Damping model at SF=0.27 57
Figure 39. Contour plot equivalent plastic strain of Damping model at SF=0.27 58