FIELD OF INVENTION
[0001] The present invention relates to a crash box, and more particularly to
the crash box having a fractal design with improved energy absorption.
BACKGROUND
[0002] Improving the structural crashworthiness performance of an automobile
is a major concern for most of vehicle manufacturers. Vehicles are equipped with
energy absorbing structures such as bumpers having crash boxes to ensure the
safety of passengers or reduce damage of a vehicle body in a vehicle collision. The
crash boxes are provided between bumper and a side frame of the vehicle.
Conventional crash boxes are made up of thin steel sheets of AHSS grade and have
different shapes such as circular, square and multi-cells tubes etc. One example of
such conventional crash box is shown in Figure 10. The crash box as shown in
Figure 10, has a rectangular shape and has benefits such as simple structural
configuration, ease of manufacturability and cost effectiveness. However, it was
found that even though crash boxes having simple shapes such as square, rectangle
and circular are easy to manufacture, they do not qualify for high energy absorbing
capacity during the crash (such as frontal crash) of the vehicle. Accordingly, a crash
box which meets or exceeds energy absorption targets during a crash without
increasing in size and without adding weight, or with a reduction in weight, is
desirable.
OBJECTIVE OF INVENTION
[0003] It is an object of the invention to provide a bio-inspired fractal crash box
design having improved the energy absorption of the crash member with nearly
using same quantity of AHSS material.
[0004] It is an object of the invention to provide a crash box design which meets
or exceeds energy absorption targets during a crash without increasing in size and
without adding weight, or with a reduction in weight.
[0005] Another objective of the present invention to provide a crash box design
which can effectively absorb the collision energy, thereby reducing the damages
received by a vehicle body or an impact received by passengers of the vehicle.

SUMMARY OF INVENTION
[0006] This summary is provided to introduce concepts related to a bio-inspired
fractal crash box design. The concepts are further described below in the detailed
description. This summary is not intended to identify key features or essential
features of the claimed subject matter, nor is it intended to be used to limit the
scope of the claimed subject matter.
[0007] In one aspect of the present invention, a crash box is provided. The crash
box comprises a body portion. The body portion comprises at least two outwardly-
projecting corner portions, and at least one flat portion positioned between the at
least two outwardly-projecting corner portions.
[0008] In an embodiment, the body portion is hollow tube portion obtained by
joining a first member and a second member. In an embodiment, each of the first
member and the second member is made of sheet metal. In an embodiment, each
of the first member and the second member is made of aluminum or aluminum
alloy. In an embodiment, each of the first member and the second member is made
of steel sheet.
[0009] In an embodiment, the length of the body portion is varied in the range of
120 to 250 mm. In an embodiment, the length of the body portion is 125 mm. In
an embodiment, the perimeter of the body portion is varied in the range of less than
equal to 2.5 times of the length of the body portion. In an embodiment, the
perimeter of the body portion is 304 mm.
[0010] In an embodiment, each of the at least two outwardly-projecting corner
portions is a semi-circular portion having a radius (R). In an embodiment, the
radius (R) of each the at least two outwardly-projecting corner portions is varied
in the range of 14 to 18 mm.
[0011] In an embodiment, the width of the each of the at least one flat portion
should be 1.6 times the radius (R) of each one outwardly projecting corner portion.
In an embodiment, the width of the each of the at least one flat portion is 25.76
mm.

[0012] In an embodiment, the crash box comprises four flat portions and four
outwardly-projecting corner portions.
[0013] In an embodiment, the crash box comprises at least one protruding
portion disposed on the at least two outwardly-projecting corner portions. In an
embodiment, each of the at least one protruding portion is elliptical in shape having
a ratio of a major axis diameter to a minor axis diameter to be 4.375 and a depth
varying in the range of 3 to 5 mm. In an embodiment, each of the at least one
protruding portion is elliptical in shape having a diameter of 35 mm in major axis,
diameter of 8 mm in the minor axis, and a depth of 4.5 mm. In an embodiment, the
at least one protruding portion is positioned at 4.3 mm from an edge of the body
portion.
[0014] In an embodiment, the crash box comprises at least one groove provided
on the at least one flat portion. In an embodiment, each of the at least one groove
is elliptical in shape having a major axis diameter to be 0.65 times the length of the
at least one of the flat portion, diameter varying in the range of 4mm to 7.5 mm in
the minor axis, and a depth varying in the range of 1 to 2.5 mm.
[0015] In an embodiment, at least one groove includes a first groove, a second
groove, a third groove and a fourth groove.
[0016] In an embodiment, the first groove is elliptical in shape having a diameter
of 16.5 mm in major axis, diameter of 7.5 mm in the minor axis, and a depth of 2.5
mm. In an embodiment, the first groove is positioned at 2 mm from an edge of the
body portion.
[0017] In an embodiment, the second groove is elliptical in shape having a
diameter of 16.5 mm in major axis, diameter of 6.4 mm in the minor axis, and a
depth of 2 mm. In an embodiment, the second groove is positioned at 15 mm from
the first groove.
[0018] In an embodiment, the third groove is elliptical in shape having a diameter
of 16.5 mm in major axis, diameter of 5.2 mm in the minor axis, and a depth of 1.5
mm. In an embodiment, the third groove is positioned at 15 mm from the second
groove.

[0019] In an embodiment, the fourth groove is elliptical in shape having a
diameter of 16.5 mm in major axis, diameter of 4 mm in the minor axis, and a depth
of 1 mm. In an embodiment, the fourth groove is positioned at 15 mm from the
third groove.
[0020] In an embodiment, the at least one groove is provided on two flat portions
facing opposite to one another.
[0021] In an embodiment, the crash box is provided with a bumper device of a
vehicle.
[0022] In an embodiment, the first member and the second member are joined
by spot welding. In an embodiment, spot weld locations are positioned equidistant
from one another along the length of the body portion.
[0023] In an embodiment, a fillet of 1mm is provided with at least one protruding
portion and at least one groove.
[0024] In another aspect of the present invention, a crash box is provided. The
crash box comprises a body portion. The body portion comprises at least two
outwardly-projecting corner portions and at least one flat portion positioned
between the at least two outwardly-projecting corner portions. The body portion
also comprises at least one protruding portion disposed on the at least two
outwardly-projecting corner portions. The body portion further comprises at least
one groove provided on the at least one flat portion.
[0025] Other features and aspects of this disclosure will be apparent from the
following description and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 illustrates a bumper device including a crash box, according to
an embodiment of the present invention;
[0027] Figures 2, 3, 4, 5, and 6 illustrate different views of the crash box,
according to an embodiment of the present invention;
[0028] Figures 7, 8, and 9 illustrate different views of the deformed crash box,
according to an embodiment of the present invention;

[0029] Figure 10 illustrates a prior art crash box, according to an embodiment of
the present invention;
[0030] Figure 11 illustrates a graph showing peak force comparison of the crash
box of the present invention and the prior art crash box, according to an
embodiment of the present invention; and
[0031] Figure 12 illustrates a graph showing energy absorption comparison of
the crash box of the present invention and the prior art crash box, according to an
embodiment of the present invention.
[0032] The drawings referred to in this description are not to be understood as
being drawn to scale except if specifically noted, and such drawings are only
exemplary in nature.
DETAILED DESCRIPTION
[0033] The detailed description of various exemplary embodiments of the
disclosure is described herein with reference to the accompanying drawings. It
should be noted that the embodiments are described herein in such details as to
clearly communicate the disclosure. However, the amount of details provided
herein is not intended to limit the anticipated variations of embodiments; on the
contrary, the intention is to cover all modifications, equivalents, and alternatives
falling within the spirit and scope of the present disclosure as defined by the
appended claims.
[0034] It is also to be understood that various arrangements may be devised that,
although not explicitly described or shown herein, embody the principles of the
present disclosure. Moreover, all statements herein reciting principles, aspects, and
embodiments of the present disclosure, as well as specific examples, are intended
to encompass equivalents thereof.
[0035] The terminology used herein is for the purpose of describing particular
embodiments only and is not intended to be limiting of example embodiments. As
used herein, the singular forms “a”, “an” and “the” are intended to include the
plural forms as well, unless the context clearly indicates otherwise. It will be further
understood that the terms “comprises”, “comprising”, “includes” and/or

“including,” when used herein, specify the presence of stated features, integers,
steps, operations, elements and/or components, but do not preclude the presence or
addition of one or more other features, integers, steps, operations, elements,
components and/or groups thereof.
[0036] It should also be noted that in some alternative implementations, the
functions/acts noted may occur out of the order noted in the figures. For example,
two figures shown in succession may, in fact, be executed concurrently or may
sometimes be executed in the reverse order, depending upon the functionality/acts
involved.
[0037] Unless otherwise defined, all terms (including technical and scientific
terms) used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which example embodiments belong. It will be further
understood that terms, e.g., those defined in commonly used dictionaries, should
be interpreted as having a meaning that is consistent with their meaning in the
context of the relevant art and will not be interpreted in an idealized or overly
formal sense unless expressly so defined herein.
[0038] Figure 1 illustrates a bumper device (120) including an exemplary crash
box (100), according to embodiment of the present invention. The bumper device
(120) extends in a lateral direction and is coupled to a frame (not shown) of a
vehicle (not shown) via the crash box (100). The bumper (120) is made of materials
including, but not limited to metal, hardened plastic etc. The bumper device (120)
along with the crash box (100) may be provided in front part of the vehicle or the
rear part of the vehicle, without limitations. In the illustrated example, the bumper
device (120) is coupled to the frame via two crash boxes (100). The crash boxes
(100) are provided between a bumper reinforcement (not shown) of the bumper
device (120) and the frame of the vehicle (not shown). The crash boxes (100) have
an identical structure and for the sake of clarity and simplicity the description now
will be described in reference to only one crash box however, the description is
equally applicable to both the crash boxes without any limitations.
[0039] Referring to Figures 2 to 6, the crash box (100) comprises a body portion
(106). The body portion (106) is a bio-inspired fractal hollow tube portion defining

an edge (121) and inner area (119). The edge (121) of the crash box (100) is
coupled to the bumper reinforcement of the bumper device (120). The body portion
(106) extends in the longitudinal direction between the bumper reinforcement and
the frame of the vehicle. The crash box (100) may comprise an attaching plate
arranged at an end away from the edge (121). The attaching plate facilitates in
coupling the crash box (100) to the frame of the vehicle. In the preferred
embodiment, the crash box (100) is welded to the bumper device (120) and the
frame of the vehicle. Alternatively, the crash box (100) may be fastened using
fastening members, without limiting the scope of the invention.
[0040] In the illustrated example, the body portion (106) is obtained by joining
a first member (102) and a second member (104). Each of the first member (102)
and the second member (104) is made of sheet metal. In the preferred embodiment,
each of the first member (102) and the second member (104) is made of steel sheet
of AHSS grade. In another embodiment, each of the first member (102) and the
second member (104) is made of aluminum or aluminum alloy. In the preferred
embodiment, the thickness of both the first member (102) and the second member
(104) may be varied in the range of 1-1.7mm. Most preferable thickness is 1.2mm.
In the preferred embodiment, the first member (102) and the second member (104)
are joined by spot welding. In the illustrated example, spot weld locations (103) on
the body portion (106) are positioned equidistant from one another along the length
of the body portion (106) (as shown in Figure 3). In another embodiment, the first
member (102) and the second member (104) may be joined in a variety of ways,
e.g. fasteners, and/or with adhesives etc., without any limitations.
[0041] In the preferred embodiment, the length of the body portion (106) can be
varied in the range of 120 to 250 mm. In the illustrated example, the length of the
body portion is 125 mm. In the preferred embodiment, the perimeter of the body
portion is varied in the range of less than equal to 2.5 times of the length of the
body portion (106). In the illustrated example, the perimeter of the body portion
(106) is 304 mm.
[0042] The body portion (106) comprises at least two outwardly-projecting
corner portions (108). In the illustrated example, the body portion (106) comprises

four outwardly-projecting corner portions (108). Alternatively, the body portion
(106) may have two or more than two outwardly-projecting corner portions (108),
without limiting the scope of the invention. In the preferred embodiment, each of
the at least two outwardly-projecting corner portions (108) is a semi-circular
portion having a radius (R) varying in the range of 14 to 18 mm. In the illustrated
example, the radius (R) is 16mm.
[0043] The body portion (106) comprises at least one protruding portion (116)
disposed on the at least two outwardly-projecting corner portions (108). In the
illustrated example, the body portion (106) comprises four protruding portions
(116) disposed on four outwardly-projecting corner portions (108). Each of the at
least one protruding portion (116) extends away from the inner area (119) from an
inner surface (133) of the body portion (106). In the preferred embodiment, each
of the at least one protruding portion (116) is elliptical in shape having a ratio of a
major axis diameter to a minor axis diameter to be 4.375 and a depth varying in the
range of 3 to 5 mm. In the illustrated example, each of the at least one protruding
portion (116) is elliptical in shape having a diameter of 35 mm in major axis,
diameter of 8 mm in the minor axis, and a depth of 4.5 mm. The at least one
protruding portion (116) is positioned at 4.3 mm from an edge (121) of the body
portion (106).
[0044] The body portion (106) comprises at least one flat portion (110)
positioned between the at least two outwardly-projecting corner portions (108). In
the illustrated example, the body portion (106) comprises four flat portions (110)
disposed between four outwardly-projecting corner portions (108). Alternatively,
the body portion (106) may have one or more than one flat portions (110), without
limiting the scope of the invention. In the preferred embodiment, the width of the
each of the at least one flat portion is 1.6 times the radius (R) of each of the at least
two outwardly projecting corner portions (108). In the illustrated example, the
width of the each of the at least one flat portion is 25.76 mm.
[0045] The body portion (106) comprises at least one groove (118) provided on
the at least one flat portion (110). Each of the at least one groove (118) extends
into the inner area (119) from an outer surface (131) of the body portion (106). In

the preferred embodiment, each of the at least one groove (118) is elliptical in shape
having a major axis diameter to be 0.65 times the length of the at least one of the
flat portion, diameter varying in the range of 4mm to 7.5 mm in the minor axis, and
a depth varying in the range of 1 to 2.5 mm.
[0046] In the illustrated example, the at least one groove (118) is provided on
each of two flat portions (110) facing opposite to one another. Alternatively, the at
least one groove (118) may be provided on each of the four flat portions (110),
without any limitations. In the illustrated example, the body portion (106)
comprises eight grooves (118), four grooves on each of the two flat portions (110).
Four of the eight grooves (118) disposed on one of the flat portion (110) are being
described herein. As the arrangement and description of the other four grooves
(118) disposed on the opposite flat portion (110) are similar to the one being
described. To avoid repetition and for clarity purpose these grooves are not
described herein.
[0047] The body portion (106) comprises four grooves (118) disposed on one of
the at least one flat portion (110). The four grooves (118) including a first groove
(118a), a second groove (118b), a third groove (118c) and a fourth groove (118d).
In the illustrated example, the first groove (118a) is elliptical in shape having a
diameter of 16.5 mm in major axis, a diameter of 7.5 mm in the minor axis, and a
depth of 2.5 mm. The first groove (118a) is positioned at a distance of 2 mm from
the edge (121) of the body portion (106).
[0048] In the illustrated example, the second groove (118b) is elliptical in shape
having a diameter of 16.5 mm in major axis, diameter of 6.4 mm in the minor axis,
and a depth of 2 mm. The second groove (118b) is positioned at a distance of 15
mm from the first groove (118a).
[0049] In the illustrated example, the third groove (118c) is elliptical in shape
having a diameter of 16.5 mm in major axis, diameter of 5.2 mm in the minor axis,
and a depth of 1.5 mm. The third groove (118c) is positioned at a distance of 15
mm from the second groove (118b).
[0050] In the illustrated example, the fourth groove (118d) is elliptical in shape
having a diameter of 16.5 mm in major axis, diameter of 4 mm in the minor axis,

and a depth of 1 mm. The fourth groove (118b) is positioned at a distance of 15
mm from the third groove (118c).
[0051] The at least one protruding portion (116) and the at least one groove (118)
form triggers that initiate and control the deformation in the event of a collision of
the vehicle.
[0052] In the preferred embodiment, a fillet of 1mm is provided with at least one
protruding portion (116) and at least one groove (118).
[0053] The inner area (119) of the body portion (106) may be filled with a
flexible cushion material for example, a gel, a fluid, or a solid material that
becomes a liquid when under pressure (such as silicone), without limiting the scope
of the invention.
[0054] The bio inspired design of the crash box (100) comprises semi-circular
shape patterns (outwardly-projecting corner portions (108)) on the four sides of the
square body portion (106) which will be manufactured with stamping the sheets
with semi-circular dies and then bending the corners. The stamped features
(grooves (118)) on flat portion (110) are provided for stable deformation and
proper folding of crash box (100). The features (protruding portions (116)) in the
curved surface (outwardly-projecting corner portions (108)) will aid in stable
deformation and it will help in decreasing the peak force.
[0055]
[0056] In a vehicle impact event, the crash box (100) receives collision load
(compression load) resulted from an impact applied to the vehicle via the bumper
reinforcement, the body portion (106) starts its buckling deformation with
deformation starting at the first groove (118a), gradually moving towards the
protruding portions (116), the second groove (118b) and so on. The bio inspired
fractal design of the crash box (100) is such that the deformation at this time allows
the crash box (100) to absorb the impact energy, thus relieving the impact applied
to the frame and like structural members of the vehicle. Figures 7, 8, and 9,
illustrates different views of the deformed crash box (100) under the collision load.
The crash box (100) as described above exceeds energy absorption targets during

a crash without increasing in size, without adding weight and without
compromising on the ease of manufacturability, as compared to the conventional
crash box (200).
[0057] Referring to Figures 11 and 12, graphs showing performance of the crash
box (100) according to the principles of the present invention as compared to the
rectangular crash box (as shown in Figure 10) are illustrated. Vehicles with crash
box (100) and the rectangular crash box (as shown in Figure 10) were subjected to
an impact with a rigid wall at a speed of 35 KMPH. Both the crash boxes were
made from AHSS material and weighed 370 grams.
[0058] In Figures 11 and 12, the grey line shows the performance of the crash
box (100) and the blue line shows the performance of the prior art crash box (200).
The deflection of the crash box (100) of the present invention is same as the
deflection of the prior art crash box (200) (conventional crash box (200)), however
the crashworthiness of the crash box (100) is better than the prior art crash box
(200). In addition, the total absorbed energy of the crash box (100) is 90.6% greater
than the prior art crash box (200) (conventional crash box (200)). The energy
absorption of rectangular design of prior art crash box (200) was found to be is 3.2
kJ and that of proposed fractal-based crash box (100) was found to be 6.1 kJ,
thereby showing a 90.6 % increase in energy absorption.
[0059] The present invention relates to the crash box (100) disposed between the
bumper device (120) and the frame of vehicle. The bio inspired fractal design of
the crash box (100) absorbs more collision energy by compressively plastically
deforming in the front-rear direction of the vehicle at the time of a collision, thereby
reducing the damages received by a vehicle body or an impact received by
passengers of the vehicle. The crash box (100) exceeds energy absorption targets
during a crash without increasing in size, without adding weight and without
compromising on the ease of manufacturability, as compared to the conventional
crash box (200).
[0060] Furthermore, the terminology used herein is for describing embodiments
only and is not intended to be limiting of the present disclosure. It will be
appreciated that several of the above-disclosed and other features and functions, or

alternatives thereof, may be combined into other systems or applications. Various
presently unforeseen or unanticipated alternatives, modifications, variations, or
improvements therein may subsequently be made by those skilled in the art without
departing from the scope of the present disclosure as encompassed by the following
claims.
[0061] The claims, as originally presented and as they may be amended,
encompass variations, alternatives, modifications, improvements, equivalents, and
substantial equivalents of the embodiments and teachings disclosed herein,
including those that are presently unforeseen or unappreciated, and that, for
example, may arise from applicants/patentees and others.
[0062] While the foregoing describes various embodiments of the invention,
other and further embodiments of the invention may be devised without departing
from the basic scope thereof. The scope of the invention is determined by the
claims that follow. The invention is not limited to the described embodiments,
versions or examples, which are included to enable a person having ordinary skill
in the art to make and use the invention when combined with information and
knowledge available to the person having ordinary skill in the art.

CLAIMS
We Claim:
1. A crash box (100) comprising:
a body portion (106), wherein the body portion (106) comprises:
at least two outwardly-projecting corner portions (108); and
at least one flat portion (110) positioned between the at least
two outwardly-projecting corner portions (108);
2. The crash box (100) as claimed in the claim 1, wherein the body portion
(106) is hollow tube portion obtained by joining a first member (102) and
a second member (104).
3. The crash box (100) as claimed in the claim 2, wherein each of the first
member (102) and the second member (102) is made of sheet metal.
4. The crash box (100) as claimed in the claim 1, wherein each of the first
member (102) and the second member (104) is made of aluminum or
aluminum alloy.
5. The crash box (100) as claimed in the claim 1, wherein each of the first
member (102) and the second member (104) is made of steel sheet.
6. The crash box (100) as claimed in the claim 1, wherein the length of the
body portion (106) is varied in the range of 120 to 250 mm.
7. The crash box (100) as claimed in the claim 6, wherein the length of the
body portion is 125 mm.
8. The crash box (100) as claimed in the claim 1, wherein the perimeter of the
body portion (106) is varied in the range of less than equal to 2.5 times of
the length of the body portion (106).
9. The crash box (100) as claimed in the claim 8, wherein the perimeter of the
body portion (106) is 304 mm.
10. The crash box (100) as claimed in the claim 1, wherein each of the at least
two outwardly-projecting corner portions (108) is a semi-circular portion
having a radius (R).

11. The crash box (100) as claimed in the claim 10, wherein the radius (R) of
each the at least two outwardly-projecting corner portions (108) is varied
in the range of 14 to 18 mm.
12. The crash box (100) as claimed in the claim 1, wherein the width of the
each of the at least one flat portion should be 1.6 times the radius (R) of
each one outwardly projecting corner portion (108).
13. The crash box (100) as claimed in the claim 12, wherein the width of the
each of the at least one flat portion is 25.76 mm.
14. The crash box (100) as claimed in the claim 1, wherein the crash box (100)
comprises four flat portions (110) and four outwardly-projecting corner
portions (108).
15. The crash box (100) as claimed in the claim 1, wherein the crash box (100)
comprises at least one protruding portion (116) disposed on the at least two
outwardly-projecting corner portions (108).
16. The crash box (100) as claimed in the claim 1, wherein each of the at least
one protruding portion (116) is elliptical in shape having a ratio of a major
axis diameter to a minor axis diameter to be 4.375 and a depth varying in
the range of 3 to 5 mm.
17. The crash box (100) as claimed in the claim 16, wherein each of the at least
one protruding portion (116) is elliptical in shape having a diameter of 35
mm in major axis, diameter of 8 mm in the minor axis, and a depth of 4.5
mm.
18. The crash box (100) as claimed in the claim 1, wherein the at least one
protruding portion (116) is positioned at a distance of 4.3 mm from an edge
(121) of the body portion (106).
19. The crash box (100) as claimed in the claim 1, wherein the crash box (100)
comprises at least one groove (118) provided on the at least one flat portion
(110).
20. The crash box (100) as claimed in the claim 19, wherein each of the at least
one groove (118) is elliptical in shape having a major axis diameter to be
0.65 times the length of the at least one of the flat portion, diameter varying

in the range of 4mm to 7.5 mm in the minor axis, and a depth varying in
the range of 1 to 2.5 mm.
21. The crash box (100) as claimed in the claim 19 and 20, wherein at least one
groove (118) includes a first groove (118a), a second groove (118b), a third
groove (118c) and a fourth groove (118d), wherein the first groove (118a),
the second groove (118b), the third groove (118c) and the fourth groove
(118d) are disposed on one of the at least one flat portion (110).
22. The crash box (100) as claimed in the claim 21, wherein the first groove
(118a) is elliptical in shape having a diameter of 16.5 mm in major axis,
diameter of 7.5 mm in the minor axis, and a depth of 2.5 mm.
23. The crash box (100) as claimed in the claim 20 and 21, wherein the first
groove (118a) is positioned at a distance of 2 mm from an edge (121) of the
body portion (106).
24. The crash box (100) as claimed in the claim 21, wherein the second groove
(118b) is elliptical in shape having a diameter of 16.5 mm in major axis,
diameter of 6.4 mm in the minor axis, and a depth of 2 mm.
25. The crash box (100) as claimed in the claim 20 to 24, wherein the second
groove (118b) is positioned at a distance of 15 mm from the first groove
(118a).
26. The crash box (100) as claimed in the claim 21, wherein the third groove
(118c) is elliptical in shape having a diameter of 16.5 mm in major axis,
diameter of 5.2 mm in the minor axis, and a depth of 1.5 mm.
27. The crash box (100) as claimed in the claim 20 to 26, wherein the third
groove (118c) is positioned at a distance of 15 mm from the second groove
(118b).
28. The crash box (100) as claimed in the claim 21, wherein the fourth groove
(118d) is elliptical in shape having a diameter of 16.5 mm in major axis,
diameter of 4 mm in the minor axis, and a depth of 1 mm.
29. The crash box (100) as claimed in the claim 20 to 28, wherein the fourth
groove (118b) is positioned at a distance of 15 mm from the third groove
(118c).

30. The crash box (100) as claimed in the claim 14 and 19, wherein the at least
one groove (118) is provided on two flat portions (110) facing opposite to
one another.
31. The crash box (100) as claimed in the claim 1, wherein the crash box (100)
is provided with a bumper device (120) of a vehicle.
32. The crash box (100) as claimed in the claim 2, wherein the first member
(102) and the second member (104) are joined by spot welding.
33. The crash box (100) as claimed in the claim 32, wherein spot weld locations
are positioned equidistant from one another along the length of the body
portion (106).
34. The crash box (100) as claimed in the claims 15 and 19, wherein a fillet of
1mm is provided with at least one protruding portion (116) and at least one
groove (118).
35. A crash box (100) comprising:
a body portion (106), wherein the body portion (106) comprises:
at least two outwardly-projecting corner portions (108);
at least one flat portion (110) positioned between the at least
two outwardly-projecting corner portions (108);
at least one protruding portion (116) disposed on the at least
two outwardly-projecting corner portions (108); and
at least one groove (118) provided on the at least one flat
portion (110).