cross section crash boxes

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(a) (b) (c) (d) Figure 3.7. Simulations of the deformation mode of circular tubes with circumferential imperfections; a/t ratios a) 5%, b)10%, c)50% and d)100% (Source: Galip and Liman 2004). The static and dynamic crushing behavior of thin walled circular stainless steel, mild steel and Al alloy tubes were investigated (Hsu and Jones 2004). Energy efficiency factor was defined as total elastic and plastic strain energy absorbed by a structural member divided by the energy absorbed in the same volume of material up to the failure in tension for evaluating the <strong>crash</strong>worthiness level of structure. It was reported that stainless steel circular tubes absorbed the highest energy among the tested tubes (Figure 3.8). However, calculated energy efficiency factor of stainless steel circular tube was found the lowest for both the quasi-static and impact loading. The critical specimen length for the transition from the efficient progressive buckling to the catastrophic global bending for quasi-static loading was found to be similar for three tubes. The critical tube length of the transition was shown to increase with increasing impact velocity. The crushing behavior of circular CR 1018 steel tubes with groove patterns was studied experimentally and numerically,(Mamalis, et al. 2003c). Model and simulations showed similar deformation modes (Figure 3.9(a) and (b)). The initial peak load value of grooved tube was found to be lower than that of non-grooved tube (Figure 3.9(c)). The number of grooves was found not to affect the peak load values in both experiments and simulations, while the number of load peaks and the values of mean load decreased with increasing number of grooves (Figure 3.9 (d)). 38
Figure 3.8. Energy absorption of quasi-statically loaded of stainless steel, mild steel and Al alloy tubes, L=250 mm (Source: Hsu and Jones 2004). Energy absorption of aluminum (AlMgSi0.5) cylindrical tubes with the induced non-axisymmetric folding patterns was studied by Marsolek and Reimeders (Marsolek and Reimerdes 2004). Special apparatus was designed to initiate diamond mode with three and four circumferential waves. During the deformation of circular tubes, the designed apparatus induced local loads and caused the deformation mode change from concertina to diamond mode (Figure 3.10(a) and (b)). Non-axisymmetric folding patterns also decreased the initial peak loads. Particularly, circular tube with 3 circumferential waves (Figure 3.10(c)) showed lower deformation loads than both concertina mode and diamond deformation mode of deformation with 4 circumferential waves (Figure 3.10(c)). 39
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OPTIMIZATION OF THE AXIAL CRUSHING
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ACKNOWLEDGEMENTS My PhD quest has b
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ÖZET KAPALI HÜCRELİ ALUMİNYUM K
Page 7 and 8: CHAPTER 4 EXPERIMENTAL DETAILS ....
Page 9 and 10: CHAPTER 8 ALUMINUM CRASH BOX OPTIMI
Page 12 and 13: Figure 3.7. Simulations of the defo
Page 14 and 15: Figure 4.9. Dimensions of tensile t
Page 16 and 17: Figure 6.21. Sequential deformation
Page 18 and 19: Figure 7.20. Sequential deformation
Page 20 and 21: LIST OF TABLES Table Page Table 4.1
Page 22 and 23: Figure 1. 1. The body in white stru
Page 24 and 25: Figure 1. 4. Commercial crash boxes
Page 26 and 27: CHAPTER 2 AL CLOSED CELL FOAMS: PRO
Page 28 and 29: The processing methods and mechanic
Page 30 and 31: Figure 2. 5 The preferred particle
Page 32 and 33: Figure 2. 8. Typical cellular struc
Page 34 and 35: Figure 2. 10. Manufacturing cost of
Page 36: Figure 2. 12. Laser assisted foamed
Page 41 and 42: Figure 2.16. Shear strength, normal
Page 43 and 44: Figure 2. 19. Yield strength vs. re
Page 45 and 46: Figure 2. 21. Unit cell geometry an
Page 47 and 48: Figure 2. 24. Load-displacement cur
Page 49 and 50: Figure 2. 26. The photographs of a
Page 51 and 52: CHAPTER 3 CRUSHING BEHAVIOR OF TUBU
Page 53 and 54: Figure 3.2. Diamond deformation mod
Page 57: deformation mode transition from ax
Page 61: (a) (c) Figure 3.10. Deformation mo
Page 65 and 66: (a) (b) Figure 3.13. a) Schematic o
Page 67 and 68: (a) (b) (c) Figure 3.15. a) Load-di
Page 72 and 73: Figure 3.18. The crush terminology.
Page 75 and 76: The quasi-static compression behavi
Page 77 and 78: Figure 3.22. The variation of speci
Page 79 and 80: Figure 3.24. Deformation modes of e
Page 81 and 82: Figure 3.27. SEA values of empty an
Page 83 and 84: Figure 3.29. (cont.) 3.5. Motivatio
Page 85 and 86: CHAPTER 4 EXPERIMENTAL DETAILS 4.1.
Page 87 and 88: (a) (b) Figure 4.3.Pictures of a) f
Page 89 and 90: oxes are shown in Figure 4.6. The l
Page 91 and 92: Figure 4.7. The method of trigger m
Page 93 and 94: 4.4. Compression Tests of Crash Box
Page 95 and 96: 4.5.2. Uniaxial Compression Testing
Page 97 and 98: Table 4.1 (Cont.) G1 T3 F2 G1T3F2 3
Page 99 and 100: Table 4.2 (Cont.) G1 T2.5 WP F2 G1T
Page 101: CHAPTER 5 SIMULATION AND OPTIMIZATI
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were constrained. Since the width o
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5.4. The Crashworthiness Optimizati
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great effect on the crushing behavi
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CHAPTER 6 EXPERIMENTAL RESULTS 6.1.
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Figure 6.3.Tensile stress-strain cu
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(a) (b) Figure 6.5. Sequential defo
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plate (Figure 6(b)). The trigger is
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(a) (b) Figure 6.9. Deformation seq
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Figure 6.12. Sequential deformation
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Figure 6.18. (cont.) (c) (a) (b) Fi
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Figure 6.20.(cont.). (b) (c) 6.5.4.
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Figure 6.21.(cont.) (b) (c) 122
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Figure 6.22.(cont.) (c) Figure 6.23
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Figure 6.24.(Cont.) (b) (c) (a) Fig
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Figure 6.26.(cont.) (b) (c) 6.6. Dy
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Figure 6.27. (cont.) (b) (c) 130
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CHAPTER 7 MODELING RESULTS OF FOAM,
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experimental tensile stress-strain
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significant effect of weld seem ope
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Figure 7.7. Deformation photo of fi
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Figure 7.11. Deformation photos of
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(a) (b) (c) Figure 7.14. Load-displ
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7.4. Simulation of Empty and Partia
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Figure 7.16. (cont.) (c) (a) Figure
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(a) (b) Figure 7.18. Sequential def
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Figure 7.19. (cont.) (b) (c) 150
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Figure 7.20. (cont.) (c) (a) Figure
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(a) (b) Figure 7.26. Experimental a
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The constructed response surface of
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Table 8.1. R 2 , Radj 2 and RMSE va
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(a) (b) Figure 8.7. Response surfac
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an empty tube wall thickness higher
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where, K is a dimensionless constan
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The dynamic simulation and analytic
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Figure 9.4. (cont.) (c) (d) Figure
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Figure 9.6. (cont.) (c) (d) (a) Fig
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Equation 9.7 can also be rewritten
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(a) (b) Figure 9.10. Energy-absorbi
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Figure 9.11. (cont.) (d) The variat
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foam filling were evaluated. The re
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13. The interaction between foam fi
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Arora, J. S.,2004,Introduction to O
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Dannemann, K. A. and Lankford, J.,
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Hall, I. W., Guden, M. and Yu, C. J
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Kim, D-K. and Lee, S., 1999, Impact
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Mamalis, A. G., Manolakos, D. E., I
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Pugsley, A. G. and Macaulay, M., 19
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T. Miyoshi, M. Itoh S. Akiyama A. K
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Zhao, H., Elnasri, I. and Girard, Y
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