cross section crash boxes

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ox design, various production routes including welding, bending and etc. involve in the processing stages. The manufacturing stages of the selected crash box design in this thesis are shown in Figure 4.4 and are composed of laser cutting of Al sheet metals, hydraulic press brake bending of the cut Al sheets and finally TIG welding of the edges of bent Al sheet. Figure 4.4. Crash box structure and crash zone. Figure 4.5. The processing stages of the tested crash boxes. Two different sets of crash boxes with the outer dimensions of 70.6x73.2x125.2 and 60x70.4x122.6 mm were prepared and tested. The technical drawings of the crash 68
oxes are shown in Figure 4.6. The larger boxes with the dimensions of 70.6x73.2x125.2 mm are coded as G1 and smaller 60x70.4x122.6 mm size boxes as G2 throughout this thesis. In both geometries of the crash boxes, trigger mechanisms were made on the outer surfaces. The trigger mechanisms function to reduce the initial peak load level and induce a more uniform deformation load. In the filled box, the trigger mechanisms also allow to position the aluminum foam filler in the mid-section of the box, between the upper and lower triggers on the outer surface. Special apparatus were constructed to form the trigger mechanisms on the surface of the crash box samples. The box was first fixed on the table of the hydraulic pres and then a steel shaping roller was slid over the parallel surface of the crash box as shown in Figure 4.7. This formed a relatively thin deformed section where the folding first triggers upon loading. The trigger mechanisms were positioned at a distance of 35 mm from the top and the bottom of the crash box. After initial experimentation of the various configurations of triggers, it was decided to place 4 trigger mechanisms on the box, two of them on one surface and the other two on the opposite surface. The trigger configuration selected was found to result in a folding mechanism progressing through the filled sections, not through the compression test plates. Al foam filler section was 60 mm thick, which was approximately half of the length of the crash box. The weight of each filler was measured before filling the boxes. Two groups of experimental crash boxes were prepared for the compression testing. In the first group boxes, the tests were performed without montage parts. For this, the montage part of the crash boxes was removed simply by cutting the montage parts (Figure 4.8(a)). In the second group, the boxes were tested with the montage plates. In this group of samples, corrugated sections, two rectangular holes of 12x12 mm in size, on each surface of the boxes were created at the upper section of the box as seen in Figure 4.8(a). Few crash boxes were tested with montage parts without corrugated sections in order to determine the effect of montage parts on the crashing behavior. The thicknesses of the boxes tested were 2, 2.5 and 3 mm (Figure 4.8 (c)). 69
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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
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CHAPTER 4 EXPERIMENTAL DETAILS ....
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CHAPTER 8 ALUMINUM CRASH BOX OPTIMI
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Figure 3.7. Simulations of the defo
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Figure 4.9. Dimensions of tensile t
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Figure 6.21. Sequential deformation
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Figure 7.20. Sequential deformation
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LIST OF TABLES Table Page Table 4.1
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Figure 1. 1. The body in white stru
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Figure 1. 4. Commercial crash boxes
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CHAPTER 2 AL CLOSED CELL FOAMS: PRO
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The processing methods and mechanic
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Figure 2. 5 The preferred particle
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Figure 2. 8. Typical cellular struc
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Figure 2. 10. Manufacturing cost of
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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.
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: (a) (b) Figure 4.3.Pictures of a) f
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
Page 105: considered in axial and transverse
Page 109 and 110: were constrained. Since the width o
Page 116 and 117: 5.4. The Crashworthiness Optimizati
Page 118 and 119: great effect on the crushing behavi
Page 120: CHAPTER 6 EXPERIMENTAL RESULTS 6.1.
Page 124 and 125: Figure 6.3.Tensile stress-strain cu
Page 126 and 127: (a) (b) Figure 6.5. Sequential defo
Page 128 and 129: plate (Figure 6(b)). The trigger is
Page 130 and 131: (a) (b) Figure 6.9. Deformation seq
Page 132 and 133: 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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