cross section crash boxes

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)).
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