U.S. patent application number 11/996622 was filed with the patent office on 2008-08-21 for structural elements made from syntactic foam sandwich panels.
This patent application is currently assigned to LOC COMPOSITES PTY LTD. Invention is credited to Darren James Browne.
Application Number | 20080199682 11/996622 |
Document ID | / |
Family ID | 37683685 |
Filed Date | 2008-08-21 |
United States Patent
Application |
20080199682 |
Kind Code |
A1 |
Browne; Darren James |
August 21, 2008 |
Structural Elements Made From Syntactic Foam Sandwich Panels
Abstract
A structural member comprising at least one syntactic foam
sandwich panel; the sandwich panel having a syntactic foam core and
at least one skin; and at least one reinforcement element attached
to the sandwich panel.
Inventors: |
Browne; Darren James; (
Queensland, AU) |
Correspondence
Address: |
STITES & HARBISON, PLLC
400 W MARKET ST, SUITE 1800
LOUISVILLE
KY
40202-3352
US
|
Assignee: |
LOC COMPOSITES PTY LTD
Holland Park, Queensland
AU
|
Family ID: |
37683685 |
Appl. No.: |
11/996622 |
Filed: |
July 26, 2006 |
PCT Filed: |
July 26, 2006 |
PCT NO: |
PCT/AU06/01052 |
371 Date: |
January 24, 2008 |
Current U.S.
Class: |
428/319.1 ;
428/319.3 |
Current CPC
Class: |
Y10T 428/24999 20150401;
E01D 2/00 20130101; E04B 5/026 20130101; Y10T 428/249991 20150401;
E04B 5/04 20130101; E04C 3/28 20130101; E04C 3/291 20130101; E01D
2101/40 20130101 |
Class at
Publication: |
428/319.1 ;
428/319.3 |
International
Class: |
E04C 2/26 20060101
E04C002/26; E04C 2/10 20060101 E04C002/10; E04C 2/24 20060101
E04C002/24; E04C 2/38 20060101 E04C002/38 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 26, 2005 |
AU |
2005903962 |
Claims
1. A structural member comprising: at least one syntactic foam
sandwich panel; the sandwich panel having a syntactic foam core and
at least one skin; and at least one reinforcement element attached
to the sandwich panel.
2. The structural member of claim 1 wherein the reinforcement
element is made from a section of steel, concrete, timber, fibre
reinforced polymers.
3. The structural member of claim 1 wherein an adhesive is used to
adhere the at least one syntactic foam sandwich panel to the at
least one reinforcement element.
4. The structural member of claim 1 wherein tie elements that span
across the glue joints in order to avoid delamination of the
adhesive and provide the assembly with robustness. The tie elements
may be made from steel, concrete, timber, fibre reinforced polymers
or any other material. The tie elements might also act as a
reinforcement element.
5. The structural member of claim 1 wherein the at least one
reinforcement element is made from fibre reinforced polymers, the
fibre being selected from glass, carbon, Kevlar, thermoplastic
fibres or combinations therefore and the polymer selected from
polyester, vinylester, epoxy, phenolic, polyurethane, thermoplastic
resins or combinations thereof.
6. The structural member of claim 1 wherein the syntactic sandwich
panel includes microspheres, the microspheres being selected from
polymeric materials including epoxy resin, unsaturated polyester
resin, silicone resin, phenolics, polyvinyl alcohol, polyvinyl
chloride, polypropylene, and polystyrene
7. The structural member of claim 1 wherein the syntactic sandwich
panel includes microspheres, the microspheres being selected from
inorganic materials such as glass, silica-alumina ceramics or
Cenospheres (hollow fly ash particles).
8. The structural member of claim 1 wherein the syntactic sandwich
panel include skins, the skins being made from fibre reinforced
polymers, the fibres being selected from glass, carbon, Kevlar,
thermoplastics or combinations thereof and the polymer being
selected from polyester, vinylester, epoxy, phenolic, polyurethane,
thermoplastics or combination thereof.
9. The structural member of claim 1 wherein the skins includes a
polymer and the syntactic foam uses a polymer, the polymers being
the same.
10. The structural member of claim 1 wherein the syntactic foam
sandwich panel is produced in single manufacturing process.
11. The structural elements may include bulkheads, diaphragms,
strong points and/or internal ties.
12. A method of producing an improved structural element, said
method including the steps of: obtaining at least one syntactic
foam sandwich panel; obtaining at least one reinforcement element;
and joining the at least one syntactic foam sandwich panel and
reinforcement element to form the improved structural element.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a method of manufacturing
structural elements.
BACKGROUND OF THE INVENTION
[0002] The superior structural properties of fibre reinforced
polymer composites are well recognised. However, to date there have
been difficulties with producing viable structural elements of
fibre reinforced polymer composites due to cost constraints.
[0003] A popular approach to producing structural elements using
fibre reinforced polymers has been through the use of the
pultrusion process. However, the dies and machines needed to
produce large structural elements with this method are very
expensive. Further, many of the structures being produced require
"one-off" construction and therefore are not economically produced
using the pultrusion process.
[0004] It is well known from basic engineering mechanics that in
most structural members under load there are areas in the member
that are subjected to much higher internal stresses than other
areas in the same member. For example in a beam loaded in uniform
bending the material near the top and bottom of the beam are
subjected to significantly higher bending stresses than material
near the centre of the beam. Hence locating large amounts of
expensive fibre composite material near the centre of such a beam
is generally uneconomical. However, there is limited flexibility in
the pultrusion process to incorporate other materials or to vary
the orientation of the fibres.
[0005] In order to incorporate other materials and to optimize the
fibre orientation in large structural elements many of them are
made using alternative production methods such as hand-lay up or
resin infusion methods. However, these methods require large moulds
which are generally specific to a particular type of structural
member. Hence, if another structural element needs to be produced,
another mould is required reducing cost effectiveness. Furthermore,
the labour involved in these alternative manufacturing methods is
quite significant leading to expensive products.
OBJECT OF THE INVENTION
[0006] It is an object of the invention to overcome and/or
alleviate one or more of the above disadvantages or provide the
consumer with a useful or commercial choice.
SUMMARY OF THE INVENTION
[0007] In one form, the invention resides in a structural member
comprising: [0008] a least one syntactic foam sandwich panel; the
sandwich panel having a syntactic foam core and at least one skin;
and [0009] at least one reinforcement element attached to the
sandwich panel.
[0010] The syntactic foam core may include microspheres made from
polymeric materials such epoxy resin, unsaturated polyester resin,
silicone resin, phenolics, polyvinyl alcohol, polyvinyl chloride,
polypropylene, and polystyrene or from inorganic materials such as
glass, silica-alumina ceramics or Cenospheres (hollow fly ash
particles)
[0011] The skins of the syntactic foam sandwich panels may be made
from fibre reinforced polymers. The fibres may be made from glass,
carbon, Kevlar, thermoplastics or combinations thereof. The polymer
may be made of polyester, vinylester, epoxy, polyurethane,
thermoplastics or combination thereof. Preferably the polymer used
in the skins is the same as that used in the syntactic foam. More
preferably the syntactic foam sandwich panel is produced in single
manufacturing process, in this way a strong primary bond can be
created between the skins and the syntactic foam core.
[0012] The reinforcement elements may be made from steel, concrete,
timber, fibre reinforced polymers or any other material. An
adhesive is typically used to adhere the syntactic foam sandwich
panels to the reinforcement elements.
[0013] If the reinforcement elements are made from fibre reinforced
polymers, then the fibres may be made from glass, carbon, Kevlar,
thermoplastic or combinations thereof and the polymer may be made
of polyester, vinylester, epoxy, polyurethane, thermoplastic resins
or combinations thereof.
[0014] One or more tie elements may span across the adhesive in
order to avoid delamination of the adhesive and provide the
assembly with robustness. The tie elements may be made from steel,
concrete, timber, fibre reinforced polymers or any other material.
The tie elements might also act as a reinforcement element.
[0015] The structural elements may include bulkheads, diaphragms,
strong points and/or internal ties.
[0016] In one form, though not the only or broadest form, the
invention resides in a method of producing an improved structural
element, said method including the steps of: [0017] obtaining at
least one syntactic foam sandwich panel; [0018] obtaining at least
one reinforcement element; and [0019] joining the at least one
syntactic foam sandwich panel and reinforcement element to form the
improved structural element.
[0020] The structural elements produced using this method may be
used in conjunction with each other to produce improved
structures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Embodiments of the invention will be described with
reference to the accompanying drawings in which:
[0022] FIG. 1A is a side view of a syntactic foam sandwich
panel;
[0023] FIG. 1B is a transverse cross sectional view of the sandwich
panel according to FIG. 1A;
[0024] FIG. 2 is a transverse cross sectional view of a structural
element according to a first embodiment of the invention;
[0025] FIG. 3 is a transverse cross sectional view of a structural
element according to a second embodiment of the invention;
[0026] FIG. 4 is a transverse cross sectional view of a structural
element according to a fourth embodiment of the invention;
[0027] FIG. 5 is a transverse cross sectional view of a structural
element according to a fourth embodiment of the invention;
[0028] FIG. 6 is a transverse cross sectional view of a structural
element according to a fifth embodiment of the invention;
[0029] FIG. 7 is a transverse cross sectional view of a structural
element according to a sixth embodiment of the invention;
[0030] FIG. 8 is a transverse cross sectional view of a structural
element according to a seventh embodiment of the invention;
[0031] FIG. 9 is a transverse cross sectional view of a structural
element according to an eighth embodiment of the invention;
[0032] FIG. 10 is a transverse cross sectional view of a structural
element according to a ninth embodiment of the invention;
[0033] FIG. 11 is a transverse cross sectional view of a structural
element according to a tenth embodiment of the invention;
[0034] FIG. 12 is a side view of a reinforcement system that
incorporates a number of bulkheads;
[0035] FIG. 13 shows a perspective view of a structural element
according to an eleventh embodiment of the invention;
[0036] FIG. 14 shows a transverse cross sectional view of a
structural element according to a twelfth embodiment of the
invention;
[0037] FIG. 15A shows a perspective of a pedestrian bridge which
has been produced by combining structural elements according to the
invention;
[0038] FIG. 15B shows an end view of the same pedestrian
bridge.
[0039] FIG. 16 shows a transverse cross sectional view of a road
bridge which has been produced by combining structural elements
according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0040] FIG. 1A and FIG. 1B shows a sandwich panel 10 used to
produce structural elements as shown in FIGS. 2 to 16. The sandwich
panel has a syntactic foam core 11 and two fibre reinforced polymer
skins 12. The syntactic foam core in this embodiment is made from
epoxy resin with Cenospheres and expanded polystyrene bead fillers.
It should be appreciated that the materials used to produce the
syntactic foam core may be varied to specified need of a structural
element. The reinforced polymer skins are made from glass fibre and
epoxy resin. It should be appreciated that the syntactic fibre
reinforced polymer skins may be also made from other materials
depending on the structural requirements of a structural
member.
[0041] FIG. 2 shows a cross section of structural member 20 that
consists of a syntactic foam panel 10 having two reinforcing
elements in the form of two steel reinforcement strips 21. The two
steel reinforcement strips 21 are substantially rectangular in
transverse cross section.
[0042] In order to produce the structural member 20, two grooves
are cut in the syntactic foam core 11 of the syntactic panel 10.
Adhesive is then placed on the two steel reinforcement strips 21
and the two steel reinforcement strips 21 are located within the
grooves to contact the syntactic foam core. The two steel
reinforcement strips 21 increase the strength and stiffness.
[0043] FIG. 3 shows a cross section of a beam 30 having a syntactic
foam panel 10 and two reinforcing elements in the form of two fibre
reinforced polymer reinforcement strips 31. The two fibre
reinforced polymer reinforcement strips 31 have fibres that are
made from carbon and the polymer is epoxy resin.
[0044] The beam shown in FIG. 3 is produced by applying adhesive on
the two fibre reinforced polymer reinforcement strips 31. The two
fibre reinforced polymer reinforcement strips 31 are the placed on
respective ends of the sandwich panel to complete the beam 30. The
beam has improved strength and stiffness.
[0045] FIG. 4 shows a cross section of a beam 40 including a
sandwich panel 10 and two reinforcement elements in the form of two
fibre reinforced polymer U-shape sections 41. The two fibre
reinforced polymer U-shape sections 41 are made from pultruded
polyester-glass fibre composites that are relatively inexpensive to
manufacture.
[0046] The beam 40 is manufactured by applying adhesive to the two
fibre reinforced polymer U-shape sections 41 and placing the two
fibre reinforced polymer U-shape sections 41 over respective ends
of the sandwich panel. Due to the shape of the fibre reinforced
polymer U-shape sections 41, the contact area between the
reinforcement modules and the syntactic foam panel 10 is
significantly increased compared to the fibre reinforced polymer
reinforcement strips 31 in FIG. 3. This results in significantly
increased resistance against delamination of the two fibre
reinforced polymer U-shape sections 41 from the sandwich panel 10.
Further, the two fibre reinforced polymer U-shape sections 41 also
contact two fibre reinforced polymer skins 12. The strength of the
bond between the fibre reinforced skins 12 and fibre reinforced
polymer U-shape sections 41 is high compared to the bond formed
between the syntactic foam core 11 and the fibre reinforced polymer
U-shape sections 41. This also assists in reducing the risk of
delamination of the syntactic foam sandwich panel 10 U-shape
sections 41 from the sandwich panel 10.
[0047] FIG. 5 shows a beam 50 that is a variation of beam of FIG.
4. In this embodiment filler elements 51 in the form of epoxy resin
and Cenospheres are located between the two fibre reinforced
polymer U-shape sections 41 adjacent the two fibre reinforced
polymer skins 12.
[0048] FIG. 6 shows a beam 60 that is a variation of the beam 50
that is shown in FIG. 5. The beam 60 replaced the single syntactic
foam sandwich beam 10 with two half-width syntactic foam sandwich
panels 15.
[0049] FIG. 7 shows a beam 70 produced using a syntactic foam
sandwich panel 10, a top reinforcement element in the form of a
polymer concrete flange 71 and a bottom reinforcement panel in the
form of a pultruded polyester-glass fibre composite U-shape section
72. Adhesive is again used to adhere the polymer concrete flange
and the pultruded polyester-glass fibre composite U-shape section
72 to the syntactic foam sandwich panel 10.
[0050] FIG. 8 shows a transverse cross section of a hollow beam 80
that is formed from four syntactic foam panels 10 and two
reinforcement elements in the form of two pultruded fibre
reinforced polymer square sections 81.
[0051] To produce the hollow beam 80, the four syntactic foam
panels 10 are adhered to the two pultruded fibre reinforced polymer
square sections 81. The two pultruded fibre reinforced polymer
square sections 81. The square reinforcement elements have large
planar surfaces which bond strongly to the two fibre reinforced
polymer skins 12. The structural member of FIG. 8 can be provided
with additional bulkheads in the space between the two
reinforcement elements as shown in FIG. 12. The vertical elements
82 in FIG. 12 can be made of sections of syntactic foam panels 10
or the sections of the pultruded fibre reinforced polymer square
sections 81.
[0052] FIG. 9 shows a transverse cross section of a hollow beam 90
made from four syntactic foam sandwich panels 10 and reinforcement
elements in the form of four angle sections 91. The angle sections
91 are made of steel. The hollow beam is formed by adhering the
four syntactic foam sandwich panels together and adhering the four
angle sections in respective corners. The angle sections provide
the hollow beam with reinforced corners. The hollow beam may be
provided with bulkheads as shown in FIG. 12.
[0053] FIG. 10 shows a larger hollow beam 100 that consists of
three syntactic foam panels 10 and two different types of
reinforcement elements. The first reinforcement element is in the
form of two fibre reinforced polymer U-shape sections 101 whilst
the second-reinforcement element is in the form of four pultruded
fibre reinforced polymer square sections 102. The two fibre
reinforced polymer U-shape sections 101 are made of glass fibre
reinforced phenolic resin whilst the four pultruded fibre
reinforced polymer square sections 102 are made of carbon fibre
reinforced vinyl ester resin.
[0054] The hollow beam 100 is manufactured by using adhering the
four pultruded fibre reinforced polymer square sections 102 and the
syntactic foam panels 10 are together using an epoxy adhesive. The
fibre reinforced polymer U-shape sections 101 are then adhered to
the syntactic foam panels 10 using the phenolic resin. The space
between the reinforcement modules 92 can be provided with bulkheads
as shown in FIG. 12 as is required.
[0055] FIG. 11 shows a hollow beam 110 that is a variation of beam
100 shown in FIG. 10. The hollow beam 110 has a top first
reinforcement member in the form of a polymer concrete member 111
that replaces the top fibre reinforced polymer U-shape sections
101. The polymer concrete member 111 combines good compression
capacity with excellent durability.
[0056] FIG. 13 shows a solid beam 120 having a syntactic foam
sandwich panel 10 and a reinforcement element in the form of a
layer of polymer concrete 121. The polymer concrete layer 121
provides the sandwich panel with improved wear resistance and
compression capacity.
[0057] FIG. 14 shows a solid beam 130 consisting of two syntactic
foam sandwich panels 10 and a reinforcement element in the form of
a layer of standard concrete 131.
[0058] The solid beam 130 is formed by adhering the two syntactic
foam sandwich panels 10 together using an epoxy adhesive. The top
of the double syntactic foam sandwich panel is provided with an
aggregate interface 132. The aggregate interface 133 is made of
aggregate having an average size of 10 mm and is adhered to a top
fibre reinforced polymer skin 12 of the syntactic foam sandwich
panel 10 with epoxy adhesive. The layer of standard concrete 131 is
then laid directly onto the aggregate interface. The concrete layer
is approximately 150 mm thick. During the casting of the standard
concrete, the syntactic foam panels act as formwork and support the
wet concrete. Once the concrete has cured the syntactic foam
sandwich panels act as external fibre composite reinforcement for
the concrete. This aggregate interface 133 provides an excellent
bonding surface for the layer of polymer concrete 132 to prevent
delamination of the layer of standard concrete 132 from the top of
the syntactic foam sandwich panel 10.
[0059] FIG. 15A and FIG. 15B show an example of a pedestrian bridge
consisting of structural elements produced using the current
method, which have been used in conjunction with each other to
produce improved structures. The bridge has multiple deck planks
135 which are made of the structural element shown in FIG. 13. The
longitudinal bridge beams 140 are made of the structural element
shown in FIG. 10. The posts 150 are made from the structural
element shown in FIG. 9. The rails of the hand rails 160 are made
from the structural element shown in FIG. 6.
[0060] FIG. 16 shows an example of a road bridge consisting of
structural elements produced using the current method, which have
been used in conjunction with each other to produce improved
structures. The bridge beams 170 are made using the principles of
the structural element shown in FIG. 11. The concrete deck 180 is
reinforced using the principle of the structural element shown in
FIG. 14. The bottom flange of the bridge beams are tied together
using a syntactic foam sandwich panel 190 which is adhered to the
beams.
[0061] FIG. 17 shows another embodiment of a road bridge 200 that
consists of five syntactic foam panel beams 210 interlinked by a
syntactic foam sandwich panel deck 220. The five syntactic foam
panel beams 210 are adhered to the syntactic foam sandwich panel
deck 220. Each syntactic foam panel beam 210 includes six syntactic
foam panels 211 with adhered reinforcement in the form of nineteen
pultruded fibre reinforced polymer square sections 212. Each of the
reinforcement sections are made of glass fibre reinforced epoxy
resin. Most of the pultruded fibre reinforced polymer square
sections 212A are filed with polymer concrete. Some of the
pultruded fibre reinforced polymer square sections 212B are filled
with a steel reinforcement bar and polymer concrete. The syntactic
foam sandwich panel deck 220 is made from six syntactic foam panels
221 adhered together.
[0062] The properties of these structural elements such as
stiffness, strength and mass can be tailored to specific
applications by selection of the materials and dimensions of the
syntactic foam sandwich panels and reinforcement elements.
[0063] It should be appreciated that various other changes and
modifications may be made to the embodiments described without
departing from the spirit or scope of the invention.
* * * * *