cross section crash boxes

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Figure 1. 4. Commercial crash boxes in various geometries. Two methodologies have been recently applied to improve the energy absorption performances of crash boxes. These are the use of multiple-cell structure and filling the crash boxes with a with light-weight metallic foam. Aluminum foam filling particularly has received much interest from both academia and industry since they have relatively very low density as compared with the foams of other metals. Unlike polymeric counterparts, aluminum foams are nonflammable and absorb much more energy under increasingly high deformation loads. In addition, aluminum foams have capabilities for the attenuating noise and vibration. The gear wheel noise emissions were reported to be reduced up to 10 dB (A), with the use of Al foam filling, at the full transmission of torque and turning speed with a 25% weight saving (Stöbener and Rausch 2009). Aluminum foams have recently been considered as the candidate materials for the crash safety applications. Despite many studies on Al foam filling of the columns in the literature, which are reviewed in Chapter 3 of this thesis, there has been no extensive study on Al foam filling of commercial crash boxes experimentally and numerically. The motivations of the present thesis include (a) assessing the effect of Al foam filling on the crash performance of a commercial crash box, (ii) modeling the associated crushing behavior of the filled boxes and verifying the model results with experiments and (iii) optimization of the filled crash boxes made of different materials and alloys. It is believed that with the results of this thesis, many aspects of the Al foam filling of commercially available crash boxes will be clarified and the limits of foam filling in terms crash performance and cost will be determined. In Chapter 2 of the thesis, the production methods and mechanical behavior of Al closed cell metal foams are reviewed. Chapter 3 reviews the crash behavior of circular and rectangular cross- 4
sectioned empty and foam filled crash box structures along with the used crash analysis methodologies and terminologies. The motivations for the research conducted in this thesis are given in Chapter 4. Chapter 5 includes the experimental methods of mechanical testing of the used Al foam filler and the crash box material, 1050H14 aluminum alloy and the production steps of empty and foam filled crash boxes. The details of the numerical simulations are outlined in Chapter 6. The results of experimental and simulation studies are given in Chapter 7 and 8, respectively. The results of optimization of partially aluminum foam filled boxes with Response Surface Methodology are analyzed in Chapter 9. Chapter 10 discusses the crash efficiencies of partially foam filled crash boxes. Conclusions are drawn in Chapter 10 along with suggested future studies. 5
Page 1 and 2: OPTIMIZATION OF THE AXIAL CRUSHING
Page 3 and 4: ACKNOWLEDGEMENTS My PhD quest has b
Page 5 and 6: 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 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 and 58: deformation mode transition from ax
Page 59 and 60: Figure 3.8. Energy absorption of qu
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.
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The quasi-static compression behavi
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Figure 3.22. The variation of speci
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Figure 3.24. Deformation modes of e
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Figure 3.27. SEA values of empty an
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Figure 3.29. (cont.) 3.5. Motivatio
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CHAPTER 4 EXPERIMENTAL DETAILS 4.1.
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(a) (b) Figure 4.3.Pictures of a) f
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oxes are shown in Figure 4.6. The l
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Figure 4.7. The method of trigger m
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4.4. Compression Tests of Crash Box
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4.5.2. Uniaxial Compression Testing
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Table 4.1 (Cont.) G1 T3 F2 G1T3F2 3
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Table 4.2 (Cont.) G1 T2.5 WP F2 G1T
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CHAPTER 5 SIMULATION AND OPTIMIZATI
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considered in axial and transverse
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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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Page 136 and 137:
Page 138 and 139:
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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Page 176 and 177:
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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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