WO2018005380A1

WO2018005380A1 - Lightweight flame resistant composite panel and panel attachment system

Info

Publication number: WO2018005380A1
Application number: PCT/US2017/039321
Authority: WO
Inventors: Richard FINGERHUT
Original assignee: International Composites Technologies, Inc.
Priority date: 2016-06-29
Filing date: 2017-06-26
Publication date: 2018-01-04
Also published as: US20180002107A1

Abstract

A lightweight flame-resistant composite panel is provided including a body portion and a side portion folded over the body portion. The side portion includes a channel segment adjacent to the body portion, and an overlapping segment adjacent to the channel segment. One or more panel apertures are located in the body portion and the channel segment for receiving bolts through the side of the panel. An edge reinforcement insert can be inserted underneath the channel segment in a channel defined by the folded side portion along an edge of the body portion. The edge reinforcement insert includes one or more insert apertures for receiving the one or more bolts through the panel, thereby increasing the bolt bearing strength of the panel along its edge. The edge reinforcement insert may comprise an elongated strip, a plurality of separated tabs, or an end cap, or may alternatively be contained within the panel.

Description

LIGHTWEIGHT FLAME RESISTANT COMPOSITE PANEL AND PANEL

ATTACHMENT SYSTEM

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional Application No. 62/356,297, filed June 29, 2016, and from U.S. Non-Provisional Application No. 15/631,923, filed June 23, 2017, which are incorporated by reference in their entireties.

BACKGROUND

The present invention generally relates to a lightweight composite panel for use with commercial and military cargo containers, packaging and the like, and more particularly relates to a lightweight composite panel including an edge reinforcement insert for increased bolt bearing strength.

Composite panels are widely used in the aerospace, automotive, construction, and military industries on account of their high strength yet lightweight properties. Typically lighter in weight and lower in cost than aluminum and other metal panels, composite panels are currently used for a variety of applications, including, but not limited to, aircrafts, automotive components, boats, consumer goods, corrosion-resistant industrial parts, communication satellites, sporting goods, transportation, oil and gas exploration and wind turbine construction. One common use for composite panels are in aircraft cargo containers, commonly known as unit load devices. A typical unit load device is built by placing composite panels on various sections of a frame structure, punching or drilling holes along the edges of the panel, and inserting bolts or other fasteners inside the holes to fasten the panels to the structure.

Composite panels are typically reinforced with fiber in a resin matrix. One type of fiber that is frequently used is aramid fiber, commonly marketed under the brand Kevlar® by DuPont® Protection Technologies. Aramid is favored in the military industry for use in armor and ballistic protection on account of its high tensile strength and strain properties. However, aramid is relatively flexible and high tensile in comparison to other fibers such as glass and carbon, and is therefore not widely used for aircraft and ground cargo containers or other applications in which a rigid composite panel with structural shear, tension and compression properties is desired. While composite panels are preferred over metal for a variety of applications due to their lower cost, composites are not as ductile as metal and therefore are naturally more brittle. As a result, composite panels are prone to structural failure from loads. These failures can be expensive to repair, especially where the failure extends along multiple panels of a single structural assembly. Furthermore, the presence of geometric discontinuities in panels, such as those formed by bolt holes along the edges, can result in additional failure modes including, for example, shear-out and bearing deformation. It is therefore desirable to have a lightweight, flame resistant composite panel that provides increased bolt bearing strength to reduce the risk of these additional failure modes occurring along the edges or body of the panel.

Hence, a need exists for a lightweight, flame resistant, rigid composite panel with increased edge or panel bolt bearing strength. The present invention meets this and other needs.

SUMMARY OF THE INVENTION

The present invention is directed to a lightweight, flame resistant composite panel that provides increased edge or panel bolt bearing strength in comparison to pre-existing panels. In a preferred aspect, the panel includes a folding side portion and an edge reinforcement insert that include panel and insert apertures, respectively, adjacent to an edge of the panel for receiving bolts or other fasteners. The folding side portion and edge reinforcement insert help distribute the bearing stress imposed by loads on the panel, thus reducing the risk of bearing-related failure modes such as shear-out and bearing deformation from occurring. The edge reinforcement insert may take a variety of forms, such as an elongated continuous or staggered strip with or without curved tabs, a plurality of separated tabs in triangular, radiused, rectangular, square, or other polygonal shape. In other aspects, the panel may include the folding side portion without the edge

reinforcement insert, or an edge reinforcement insert without the folding side portion. The edge reinforcement insert can also take the form of an end cap which is applied to the panel for increased bolt bearing strength.

In a further embodiment, the edge reinforcement insert is assembled or positioned inside the composite layup of the panel itself such that the panel has a uniform thickness. The edge reinforcement insert which is laid up or molded inside the composite panel may be positioned adjacent to one or more edges of the panel to provide localized edge reinforcement, or alternatively may be sized to span the entire length of the panel to provide reinforcement throughout the entire panel.

The lightweight, flame resistant composite panel is preferably reinforced with glass or carbon fibers, which unlike aramid fibers, are less flexible and more rigid, further reducing the risk of panel fracture or other failure. The composite panel is lighter or equivalent in weight to pre-existing metal panels such as aluminum, and is lower in cost. The present invention therefore cost-effectively provides a lightweight composite panel with increased bolt bearing strength to lessen the risk of bearing-related failure modes from occurring. It may be used for a variety of applications including, but not limited to, air and ground cargo containers, protective packaging for batteries and power generation, transportation structural paneling, partitions, protective liners including cargo liners.

Accordingly, in a preferred embodiment of the present invention, a lightweight composite panel is provided including a body portion and a side portion. The side portion includes a channel segment adjacent to the body portion, and an overlapping segment adjacent to the channel segment. In a preferred aspect, the body portion has a first thickness, and the side portion is tapered such that the channel segment has a second thickness greater than the first thickness of the body portion, and such that the overlapping segment has a third thickness greater than the second thickness of the channel segment. Alternatively, the body portion, the channel segment, and the overlapping segment may all have a uniform thickness.

The channel segment and the body portion include a plurality of panel apertures for receiving one or more fasteners, such as bolts. In a preferred aspect, the side portion folds over the body portion, thereby defining a channel underneath the channel segment along an edge of the body portion. The overlapping segment may be sized in thickness such that when the side portion is folded over the body portion, the overlapping segment projects toward the body portion or contacts the body portion. The plurality of panel apertures in the channel segment and body portion are positioned such that when the side portion is folded over the body portion, the plurality of panel apertures are aligned to receive the one or more fasteners through the panel adjacent to its edge. In another preferred aspect, an edge reinforcement insert is located in the channel defined by the folding side portion. The edge reinforcement insert may be loosely located in the channel; alternatively, the edge reinforcement insert may be attached to the channel segment or the body portion by conventional bonding, fusing, welding, or co-curing processes. The edge reinforcement insert includes one or more insert apertures for receiving the one or more fasteners. The one or more insert apertures are correspondingly aligned with the plurality of panel apertures to enable the edge reinforcement insert to receive the one or more fasteners extending through the panel. In this way, the folding side portion and the edge reinforcement insert increase the bolt bearing strength of the panel along its edge.

In another preferred aspect, a lightweight composite panel is provided that includes a body portion and a folding side portion with a channel segment and an overlapping segment, but without an edge reinforcement insert. The channel segment and the body portion include one or more panel apertures positioned adjacent to an edge of the body portion for receiving one or more fasteners, such as bolts. The body portion may have a uniform thickness, and the side portion may be tapered such that the channel segment has a second thickness greater than that of the body portion, and such that the overlapping segment has a third thickness greater than that of the channel segment. When the side portion is folded over the body portion, the panel apertures are aligned to receive the one or more fasteners, thus increasing the bolt bearing strength of the panel along its edge.

In yet a further aspect, a lightweight composite panel is provided having a body portion and a side portion with an edge reinforcement insert, but where the side portion does not fold over the body portion. The side portion includes one or more panel apertures adjacent to an edge of the body portion for receiving one or more fasteners, such as bolts. The edge reinforcement insert is attached, such as by bonding, fusing, welding, or curing, to the side portion. The edge reinforcement insert includes one or more insert apertures for receiving the one or more fasteners, and is positioned relative to the side portion such that the one or more insert apertures are correspondingly aligned with the one or more of the panel apertures, respectively. In this way, the one or more fasteners are received in both the edge reinforcement insert and the side portion of the panel, thus increasing the bolt bearing strength of the panel along its edge. In another embodiment of the lightweight composite panel, an edge reinforcement insert in the form of an end cap is applied to the side portion to provide increased bolt bearing strength to the panel. The end cap includes a front-facing portion and a rear- facing portion covering the side portion of the panel which can be of uniform or nonuniform thickness, and the end cap includes one or more end cap apertures for receiving one or more fasteners such as bolts. The one or more end cap apertures are

correspondingly aligned with one or more panel apertures in the side portion, respectively. In this way, the one or more fasteners can be received in both the end cap and the side portion of the panel, thus increasing the bolt bearing strength of the panel along its edge.

In a further embodiment, a lightweight composite panel is provided having a body portion of uniform thickness including one or more panel apertures for receiving one or more fasteners, such as bolts. The edge reinforcement insert is inserted into the panel during the composite layup or molding process. As a result, the edge reinforcement insert is contained within the body portion and therefore does not increase the thickness of the panel. The edge reinforcement insert includes one or more insert apertures for receiving the one or more fasteners, and is positioned such that the one or more insert apertures are correspondingly aligned with the one or more of the panel apertures, respectively. In this way, the one or more fasteners are received in both the edge reinforcement insert and the body portion of the panel, thus increasing the bolt bearing strength of the panel. The edge reinforcement insert can be positioned relative to an edge of the body portion to provide localized edge reinforcement. Alternatively, the edge reinforcement insert can be sized to span the entire length of the body portion to provide reinforcement to the entire panel. Such edge or panel reinforcement insert can form any one or more of the panel's interior or exterior composite layers.

The edge reinforcement insert used in the above embodiments may take a variety of forms. In one aspect, the edge reinforcement insert may comprise an elongated strip with either a continuous or staggered surface in which the one or more insert apertures are disposed. Additionally, the elongated strip may include one or more projecting curved tabs in which one or more insert apertures are disposed. In an alternative aspect, the edge reinforcement insert in the above embodiments may comprise a plurality of separated tabs in which the one or more insert apertures are disposed. The separated tabs may be of a variety of shapes, such as triangular, radiused, or rectangular, and are positioned around the one or more panel apertures. The edge reinforcement insert may also take the form of an end cap having a uniform or non-uniform thickness. Regardless of its shape, the edge reinforcement insert in all of the above embodiments may comprise a metal, nonmetal, or composite material.

The embodiments described above include other preferred aspects. In one aspect, the lightweight composite panel is preferably rigid or semi-rigid, and is reinforced by a fiber in a polymer resin matrix. For example, the panel may be reinforced by glass fiber or carbon fiber in a thermoset or thermoplastic resin matrix. In another aspect, the lightweight composite panel in the aforementioned embodiments may provide flame resistant protection to a temperature of up to at least one of 900 degrees Centigrade, 1,200 degrees Centigrade, or 1,650 degrees Centigrade. In yet another aspect, the lightweight composite panel of the aforementioned embodiments may include a thin core in the middle of the panel for increased stiffness, such as a crushed core or screen material. In a further aspect, the panel may be used for walls and doors. In yet a further aspect, the panels may be curved.

These and other features and advantages of the present invention will become apparent from the following detailed description of preferred embodiments which, taken in conjunction with the accompanying drawings, illustrate by way of example the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a lightweight composite panel including a folding side portion and an edge reinforcement insert.

FIG. 2 is a top plan view of the lightweight composite panel of FIG. 1.

FIG. 3 is a side elevational view of the lightweight composite panel of FIG. 1.

FIG. 4 is a cross-sectional view taken along line 4 - 4 of FIG. 1.

FIG. 5 is a top, partial breakout view of a lightweight composite panel including an edge reinforcement insert in the form of a continuous strip.

FIG. 6 is a top, partial breakout view of a lightweight composite panel including an edge reinforcement insert in the form of a continuous strip having curved tabs.

FIG. 7 is a perspective view of the edge reinforcement insert shown in FIG. 6. FIG. 8 is a cross-sectional view taken along line 8 - 8 of FIG. 7.

FIG. 9 is a top, partial breakout view of a lightweight composite panel including an edge reinforcement insert in the form of a plurality of separate tabs having a triangular shape.

FIG. 10 is a top, partial breakout view of a lightweight composite panel including an edge reinforcement insert in the form of a plurality of separate tabs having a scalloped shape.

FIG. 11 is a top, partial breakout view of a lightweight composite panel including an edge reinforcement insert in the form of a plurality of separate tabs having a rectangular shape.

FIG. 12 is a perspective view of a lightweight composite panel including an unfolded side portion.

FIG. 13 is a cross-sectional view taken along line 13 - 13 of FIG. 12.

FIG. 14 is a perspective view of the lightweight composite panel of FIG. 12 showing the attachment of the edge reinforcement insert to the unfolded side portion.

FIG. 15 is a perspective view of the lightweight composite panel of FIG. 12 depicting the folding of the side portion with attached edge reinforcement insert onto the body portion.

FIG. 16 is a perspective view of a lightweight composite panel with folding side portion, but lacking an edge reinforcement insert.

FIG. 17 is a perspective view of a lightweight composite panel including an edge reinforcement insert in the form of an end cap, where the end cap includes a front-facing portion and a rear-facing portion of uniform thickness.

FIG. 18 is a cross-sectional view taken along line 18 - 18 of FIG. 17.

FIG. 19 is a side elevational view of a lightweight composite panel including an end cap with front-facing portion of non-uniform thickness. FIG. 20 is a cross-sectional side view of a lightweight composite panel including edge reinforcement inserts contained within the panel during the composite layup or molding process.

FIG. 21A is a cross-sectional side view of a variation of the lightweight composite panel of FIG. 20 including an edge reinforcement insert sized to span the entire length of the panel.

FIG. 21B is a cross-sectional side view of another variation of the lightweight composite panel of FIG. 20 including an edge reinforcement insert sized to span the entire length of the panel.

FIG. 22 is a perspective view of lightweight composite panels as applied to a cargo container.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, FIGs. 1 - 3 illustrate a preferred embodiment of a rigid, lightweight composite panel 20 according to the present invention. The composite panel 20 includes a body portion 22 and a folded side portion 24 overlapping the body portion. The side portion includes a channel segment 26 folded over and adjacent to the body portion that includes panel apertures 28 for respectively receiving one or more fasteners, such as bolts. The side portion further includes an overlapping segment 30 adjacent to the channel segment that optionally contacts the body portion. A channel 32 extending underneath the channel segment is defined by the overlapping side portion along an edge 34 of the body portion.

A shim or edge reinforcement insert 40 with one or more insert apertures 42 (see FIG. 5) is disposed in the channel 32. The edge reinforcement insert is positioned in the channel such that its insert apertures 42 are respectively aligned with the panel apertures 28. When bolts or other fasteners are received into the panel apertures 28, they are also received in the insert apertures 42. As a result, the edge reinforcement insert increases the panel's bolt bearing strength, enabling the effective distribution of structural loads on the lightweight composite panel by allowing the edge reinforcement insert to efficiently absorb bearing loads. The edge reinforcement insert may be constructed from metal, non- metal, or composite material, is preferably light in weight, and may be of varying shapes and thickness. It may be integrally attached to the channel segment or body portion of the lightweight composite panel, for instance, by conventional bonding or co-curing processes.

Referring now to FIG. 4, the one or more panel apertures 28 are punched or drilled through the channel segment and the body portion. Additionally, the one or more insert apertures 42 are punched or drilled through the edge reinforcement insert. The one or more panel and insert apertures are aligned such that when the edge reinforcement insert is positioned underneath the channel segment, a through bore 29 is formed in the lightweight composite panel. In this way, fasteners, such as bolts, can be received in through bore 29 for fastening the lightweight composite panel and edge reinforcement insert to the structural assembly of a cargo container or the like.

The lightweight composite panel is rigid and reinforced by fibers 50 in a resin matrix 52. Preferably, the lightweight composite panel comprises glass fibers in a thermoset resin matrix such as epoxies, phenolics, cyanate ester, and polyesters. However, other combinations of fiber reinforcements and resin matrices may be used that result in a rigid panel. For example, the panel may include carbon fibers in a thermoplastic resin matrix such as nylon, polycarbonate, polypropylene, polyphenylene sulfide,

polyetherimide, or other resins. Alternatively, the panel may include glass fibers in a thermoplastic resin matrix, or carbon fibers in a thermoset resin matrix. FIGs. 5 - 11 show various forms of edge reinforcement inserts for the lightweight composite panel. In any edge reinforcement insert described in this application, the edge reinforcement insert may be metallic, non-metallic or composite.

In one aspect, as shown in FIG. 5, the edge reinforcement insert may comprise an elongated strip 44 having the one or more insert apertures 42. In another aspect, as shown in FIGs. 6 - 8, the edge reinforcement insert may comprise an elongated strip 100 having one or more insert apertures 102 extending through the strip that are located in integral scalloped or curved tabs 104. These curved tabs provide lightness in weight and ease of assembly of the edge reinforcement insert, and are positioned such that the one or more insert apertures align with the one or more panel apertures of the channel segment and body portion. The edge reinforcement inserts of FIGs. 5 and 6 may have a continuous surface, or a staggered or stepped surface. In another aspect, as shown in FIGs. 9 - 11, the edge reinforcement insert may comprise a plurality of polygonal, separated tabs having insert apertures positioned in respective alignment with the one or more panel apertures of the channel segment and body portion. For example, FIG. 9 illustrates an edge reinforcement insert comprising triangular tabs 200 having one or more insert apertures 202, FIG. 10 illustrates an edge reinforcement insert comprising radiused tabs 300 having one or more insert apertures 302, and FIG. 11 illustrates an edge reinforcement insert comprising rectangular tabs 400 having one or more insert apertures 402. As with the elongated strips, the separated tabs may also be metallic, non-metallic, or composite. However, these separated tabs provide even greater lightness in weight than the elongated strip referenced above.

Referring now to FIG. 12, the lightweight composite panel 20 is initially manufactured with the side portion 24 not folded over the body portion 22. One or more panel apertures 28 are punched or drilled into the channel segment 26 and the body portion 22. The panel apertures are correspondingly positioned so that when the side portion is eventually folded over the body portion, the panel apertures are aligned to receive one or more fasteners such as bolts through the panel. Alternatively, the panel apertures may be punched or drilled into the channel segment and body portion after the side portion has been folded, thus providing panel aperture alignment for receiving the one or more fasteners through the panel in less time. As shown in FIG. 13, the side portion is preferably tapered or stepped such that the body portion 22, channel segment 26 and the overlapping segment 30 have different thicknesses. In a preferred aspect, the overlapping segment of the side portion has a greater thickness than that of the channel segment. In this way, when the side portion is folded over the body portion, the overlapping segment may contact the body portion while leaving room for channel 32 underneath the channel segment 26. The channel segment may be identical in thickness to that of the body portion, or larger.

Referring now to FIG. 14, an edge reinforcement insert is placed on and attached to the channel segment 26. Although FIG. 14 illustrates the elongated strip 100 shown in FIGs. 6 - 8 as an example, any other edge reinforcement insert identified above will suffice. For example, the insert 40 may be used, or the plurality of separated tabs 200, 300, or 400. Regardless of which edge reinforcement insert is used, the edge

reinforcement insert is placed such that its one or more insert apertures 102 are aligned with the one or more panel apertures 28. These insert apertures are preferably punched or drilled through the edge reinforcement insert before the edge reinforcement insert is placed on the channel segment. Alternatively, the insert apertures can be punched or drilled after the edge reinforcement insert is placed on the channel segment. Once the edge reinforcement insert is placed, it is bonded, co-cured, fused, welded or otherwise attached to the channel segment using conventional processes.

After the edge reinforcement insert is attached to the side portion 24, as shown in FIG. 15, the side portion is folded over the body portion using conventional manufacturing processes. When folding is complete, the edge reinforcement insert is lodged inside the channel 32 defined by the folding side portion along the edge 34 of the body portion 22, and the one or more panel apertures on the body portion are correspondingly aligned with the one or more insert apertures of the edge reinforcement insert. One or more fasteners can then be received through the panel apertures and insert apertures. As a result, the lightweight composite panel 20 depicted in FIG. 1 with increased edge bolt bearing strength is formed.

Various modifications to the composite panel 20 are contemplated. For example, in one aspect, the side portion with attached edge reinforcement insert is not folded over the body portion, but instead remains relatively planar to the body portion as shown in FIG. 14. In such case, the edge reinforcement insert itself provides for increased bolt bearing strength for handling bearing stress of bolts or other fasteners received in the one or more insert apertures and the panel apertures. In another aspect, the side portion is folded over the body portion, but without an edge reinforcement insert, as shown in FIG. 16. In this case, the folding side portion itself provides for the increased bolt bearing strength of the panel in handling the bearing stress of fasteners received in the insert and panel apertures.

In another embodiment of the present invention as depicted in FIG. 17, a lightweight composite panel 520 is provided which includes a body portion 522, a side portion 524 including panel apertures 528 for receiving fasteners such as bolts, and an edge reinforcement insert in the form of an edge cap or end cap 550 applied over side portion 524 to provide increased bolt bearing strength to panel 520. In this embodiment, the side portion 524 does not need to be folded over the body portion 522 since the end cap itself distributes the bearing stress imposed by loads on panel 520. End cap 550 is preferably manufactured from composite material to be lightweight but strong, but it may also be metal or non-metal. An additional edge reinforcement insert (not shown) may optionally be used in combination with the end cap 550 to provide additional bolt bearing strength to the panel. For example, after edge reinforcement insert 100 is placed on the side portion of the panel as described above , end cap 550 can be placed over both the edge reinforcement insert 100 and the panel 520. The edge cap or end cap may be a 'C or 'LP shaped laminate that wraps around and attaches to the composite panel.

Referring to FIG. 18, end cap 550 includes a front-facing portion 552 and a rear- facing portion 554. The front-facing and rear-facing portions are sized to be at least as thick as the body portion 522 of the panel 520, although different thickness variations are possible. For example, the front-facing and rear-facing portions can have identical thicknesses, the front-facing portion can have a larger thickness than that of the rear-facing portion, or the rear-facing portion can have a larger thickness than that of the front-facing portion. Moreover, the front-facing and rear-facing portions can each have a uniform thickness as shown in FIG. 18, or a non-uniform thickness as shown in FIG. 19. In one exemplary embodiment, end cap 550 can vary in thickness between 0.015 inches and 0.040 inches, although smaller and larger sizes are possible.

End cap 550 includes end cap apertures 556 for receiving fasteners, such as bolts. When end cap 550 is applied to an edge of the body portion 522, as illustrated in FIG. 18, end cap apertures 556 are correspondingly aligned with panel apertures 528 such that a through bore 558 is formed in the panel 520. Bolts or other fasteners may then be received in through bore 558. When loads are thereafter imposed on the panel, end cap 550 distributes bearing stress and increases the bolt bearing strength of panel 520, thereby reducing the risk of panel shear-out, bearing failure, and other related failure modes. In this way, end cap 550 operates similarly to the aforementioned folding side portion and edge reinforcement insert in effectively distributing the bearing stress imposed by loads on the panel.

As mentioned above, the front and rear-facing portions of end cap 550 may be of non-uniform thickness. For example, FIG. 19 illustrates panel 520 where the thickness 560 of the front-facing portion 552 varies over the length of the end cap 550, peaking preferably at the location of the bolts or fasteners (not shown). In this way, end cap 550 may more effectively distribute bearing stresses imposed by loads on the panel at locations where thickness 560 is largest and improve the life of the panel. Non-uniform thickness may be present in the front-facing portion only as shown in FIG. 19, the rear-facing portion only, or in both surfaces.

FIGs. 20, 21A, and 21B illustrate other embodiments of a lightweight composite panel 620 in which one or more edge reinforcement inserts 640A, 640B are contained within the body portion 622 of the panel. Referring to FIG. 20, the body portion 622 of the panel includes one or more panel apertures 628, and each edge reinforcement insert 640A includes one or more insert apertures 642, for receiving bolts or other fasteners. Each edge reinforcement insert 640A is positioned relative to an edge 634 of the body portion such that the insert apertures and panel apertures are correspondingly aligned to form through bores 629, enabling the panel to be fastenably attached to a structural assembly such as a cargo container or the like. As the edge reinforcement inserts are contained within the body portion, the body portion is flat or of uniform thickness. In this way, the edge reinforcement inserts 640A can be manufactured into the panel without adding thickness to the edges of the body portion. Although FIG. 20 illustrates two edge reinforcement inserts contained within the panel, more or less edge reinforcement inserts may be used for increased bolt bearing strength. Edge reinforcement inserts 640A can have the same structure as any of the edge reinforcement inserts 40, 100, 200, 300, 400 previously described. Alternatively, as illustrated in FIGs. 21A and 21B, the lightweight composite panel

620 may include an edge reinforcement insert 640B which is sized to span the length of the entire panel 620, or even a substantial portion of the panel 620. In this way, the edge reinforcement insert 640B is not localized to the edges of the body portion 622, but provides reinforcement throughout the entire panel. This reinforcement allowing for hole or bolt bearing strength can be contained in an interior composite layer 650 of the panel, as illustrated in FIG. 21A, or in an exterior composite layer 660 of the panel, as illustrated in FIG. 21B. The material for the reinforcement may also act as a thermal insulation barrier, and can include a foam core, reinforced fiber core, honeycomb core, standoff, or the like. Moreover, the reinforcing insert can be a sandwich construction with face sheets, or a solid laminate.

FIG. 22 illustrates an application of multiple lightweight composite panels 20 in different shapes and sizes as used on a cargo container 700. Although lightweight composite panel 20 with edge reinforcement insert 40 is here specifically depicted, other aforementioned panel embodiments and edge reinforcement inserts (e.g. as applied externally to, or contained within, the panel) may be used instead or in combination.

The panels are mechanically attached on their sides to the framework of a structural assembly 702. Fasteners 704, such as bolts, are received in the panel apertures of the folding side portion 24 and body portion 22, as well as the insert apertures of the edge reinforcement insert. The folding side portions 24 may be located on any side of the panels. When bearing stresses and other loads are imposed on the panels, the foldable side portion and/or edge reinforcement insert effectively distribute the forces as a result of their increased bolt (or other fastener) bearing strength. In this way, the risk of bearing-related failure modes such as shear-out and bearing deformation is reduced, saving the potential cost required in having to repair fractured or otherwise failed panels. The panels can be similarly used to provide structural benefits in other potential applications including air and ground cargo containers, protective packaging, protective packaging for batteries and power generation, transportation structural paneling, partitions, protective liners including cargo liners, and the like.

The composite panel, the edge reinforcement insert, and the edge cap in any of the above-described embodiments can be flame resistant to very high or elevated temperatures above ambient temperature. For example, the composite panels in the above-described embodiments can resist temperatures for extended periods of time of up to 900 degrees Centigrade (1650 degrees Fahrenheit), of up to 1,200 degrees Centigrade (approximately 2, 190 degrees Fahrenheit), and/or of up to 1,650 degrees Centigrade, depending on the materials used. Any one of the internal or external composite layers of the lightweight composite panel embodiments can be designed to have a lower or greater degree of flame resistance, depending on the panel's application.

While certain embodiments have been illustrated and described herein, those embodiments are not necessarily to be construed as advantageous over other embodiments for implementing the present subject matter. Other variations and equivalents are possible and should be considered within the scope of the present subject matter.

Claims

What is claimed is:

1. A lightweight, flame resistant composite panel comprising: a body portion and a side portion, the side portion including a channel segment adjacent to the body portion, the channel segment and body portion including a plurality of panel apertures for receiving one or more fasteners, the side portion further including an overlapping segment adjacent to the channel segment, the side portion overlapping the body portion such that the overlapping segment projects toward the body portion and thereby defines a channel underneath the channel segment along an edge of the body portion, the plurality of panel apertures in the channel segment and body portion being aligned to receive the one or more fasteners through the body portion adjacent to the edge.

2. The lightweight composite panel of Claim 1, wherein the body portion is of uniform thickness.

3. The lightweight composite panel of Claim 1, wherein the side portion is tapered, wherein the body portion has a first thickness, wherein the channel segment has a second thickness greater than the first thickness of the body portion, and wherein the overlapping segment has a third thickness greater than the second thickness of the channel segment.

4. The lightweight composite panel of Claim 1, wherein the lightweight composite panel is rigid and is reinforced by a fiber selected from the group consisting of glass fiber and carbon fiber, and wherein the fiber is bound by a polymer resin matrix selected from the group consisting of thermosets and thermoplastics.

5. The lightweight composite panel of Claim 1, further comprising an edge reinforcement insert located in the channel and connected to the body portion, the edge reinforcement insert including one or more insert apertures for receiving the one or more fasteners, the edge reinforcement insert being positioned relative to the channel segment and the body portion such that the one or more insert apertures are aligned with a corresponding one or more of the plurality of panel apertures, respectively.

6. The lightweight composite panel of Claim 5, wherein the edge reinforcement insert includes an elongated strip, the one or more insert apertures being disposed within the elongated strip, the elongated strip including a material selected from the group consisting of metal, nonmetal, and composite, and the elongated strip having one of a continuous surface or a staggered surface.

7. The lightweight composite panel of Claim 6, wherein the edge reinforcement insert includes one or more curved tabs projecting from the elongated strip, the one or more insert apertures being disposed within the one or more curved tabs, the one or more curved tabs including a material selected from the group consisting of metal, nonmetal, and composite.

8. The lightweight composite panel of Claim 1, wherein the edge reinforcement insert includes a plurality of separated tabs, the one or more insert apertures being disposed within the plurality of separated tabs, the plurality of separated tabs each including a material selected from the group consisting of metal, nonmetal, and composite.

9. A lightweight, flame resistant composite panel comprising: a body portion and a side portion, the side portion including one or more panel apertures for receiving one or more fasteners, the one or more panel apertures being adjacent to an edge of the body portion; and an edge reinforcement insert applied to the side portion of the panel body, the edge reinforcement insert including one or more insert apertures for receiving the one or more fasteners, the edge reinforcement insert being positioned relative to the side portion such that the one or more insert apertures are aligned with a corresponding one or more of the panel apertures, respectively.

10. The lightweight composite panel of Claim 9, wherein the lightweight composite panel is rigid and is reinforced by a fiber selected from the group consisting of glass fiber and carbon fiber, and wherein the fiber is bound by a polymer resin matrix selected from the group consisting of thermosets and thermoplastics.

11. The lightweight composite panel of Claim 9, wherein the edge reinforcement insert is an elongated strip, the one or more insert apertures being disposed within the elongated strip, the elongated strip including a material selected from the group consisting of metal, nonmetal, and composite.

12. The lightweight composite panel of Claim 11, wherein the edge reinforcement insert includes one or more curved tabs projecting from the elongated strip, the one or more insert apertures being disposed within the one or more curved tabs.

13. The lightweight composite panel of Claim 9, wherein the edge reinforcement insert includes a plurality of separated tabs, the one or more insert apertures being disposed within the plurality of separated tabs.

14. The lightweight composite panel of Claim 9, wherein the edge reinforcement insert is an end cap applied to the side portion, the end cap including a front-facing portion and a rear-facing portion covering the side portion of the panel, the end cap including one or more end cap apertures for receiving one or more fasteners, the one or more end cap apertures correspondingly aligned with the one or more panel apertures, respectively.

15. The lightweight composite panel of Claim 14, wherein the front-facing portion and the rear-facing portion are of uniform thickness.

16. The lightweight composite panel of Claim 14, wherein a thickness of at least one of the front-facing portion or the rear-facing portion varies over the length of the end cap.

17. The lightweight composite panel of Claim 16, wherein the thickness of at least one of the front-facing portion or the rear-facing portion peaks at the location of the one or more end cap apertures.

18. A lightweight, flame resistant composite panel comprising: a body portion including one or more panel apertures for receiving one or more fasteners, the body portion being of uniform thickness; and an edge reinforcement insert contained within the body portion, the edge reinforcement insert including one or more insert apertures for receiving the one or more fasteners, the edge reinforcement insert being positioned relative to an edge of the body portion such that the one or more insert apertures are aligned with a corresponding one or more of the panel apertures, respectively.

19. The lightweight composite panel of Claim 18, wherein the edge reinforcement insert is sized to span an entire length of the body portion.

20. The lightweight composite panel of Claim 18, wherein the composite panel is flame resistant to a temperature of up to at least one of 900 degrees Centigrade, 1,200 degrees Centigrade, or 1,650 degrees Centigrade.