Shaped structural panel with open cell core

Abstract

A panel includes a first panel, a second panel, and an edge cap. The first panel and the second panel each include a core sandwiched between and bonded to a first skin and a second skin. The edge cap is positioned between and bonded to the first panel and the second panel such that a cavity is defined by the first panel, the second panel, and the edge cap. The cavity is configured to receive an insert and is isolated from forces transmitted between the first panel and the second panel.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of transportation, and more particularly to structural panels. The structural panels can be used as insulated structural panels for insulated cargo containers or as insulated walls for structures. BACKGROUND

[0002] Aircraft cargo is typically transported in containers commonly referred to as unit load devices (“ULDs”), which are loaded in the cargo holds of an aircraft, which can be located below and / or above a deck, for example, below a deck in a passenger aircraft or below and above a deck in a cargo aircraft. The external dimensions and shape of the ULDs vary depending on the type of aircraft, such that the external dimensions of the ULDs are determined by the type of aircraft. Typically, one end or side of the ULD is open, regardless of the shape or geometry of the container, for loading and unloading cargo. Various door closures can be used to open and close the open end of the ULD. The unladen weight of the ULD is very important, as even a slight reduction in the unladen weight of the ULD results in significant savings in fuel costs for transporting the ULD during its useful life. Additionally, a reduction in the unladen weight of the ULD would allow for an increase in the cargo carrying capacity.

[0003] Transporting perishable aircraft cargo can require the ULD to be insulated and / or refrigerated. Some perishable aircraft cargo can require the interior of the ULD to be maintained below a certain temperature or within a certain temperature range. Typically, to insulate the ULD, an R-value suitable for the ULD has been achieved using an insulated panel including a foam core or a foam core with air pockets. The foam core typically has an R-value of R-5 per inch and tends to be thick (e.g., at least 1 inch) to achieve a suitable R-value. The thickness of the panel can reduce the cargo space within the ULD and / or increase the unladen weight of the ULD. Typically, to refrigerate the ULD, specialized refrigeration equipment, which is certified for use on an aircraft, is used, which is disposed within or secured to the ULD. The specialized refrigeration equipment can also include a battery, which is certified for use on an aircraft. The refrigeration equipment and battery tend to be heavy and bulky, thereby increasing the weight of the ULD and reducing the cargo space of the ULD.

[0004] Structural panels have also been used as building materials to form walls of fixed structures and buildings. It can be advantageous to insulate such structural panels to reduce the amount of heat transferred into or out of the structure formed by the structural panels. For example, insulated structural panels can improve the thermal efficiency of heating and cooling systems of a building formed by the structural panels. SUMMARY

[0005] The present disclosure relates to a structural panel formed from a first plate and a second plate spaced apart from each other to define a cavity therebetween. Each of the first plate and the second plate includes a core sandwiched between two skins. The first plate and the second plate are spaced apart by one or more edge caps configured to transfer forces between the first plate and the second plate such that the cavity is isolated from the forces transferred between the first plate and the second plate.

[0006] In one embodiment of the present disclosure, a panel includes a first plate, a second plate, and an edge cap. The first plate includes a first core sandwiched between and bonded to a first skin and a second skin. The second plate includes a second core sandwiched between and bonded to a third skin and a fourth skin. The edge cap is positioned between and bonded to the first and second plates such that a cavity is defined by the first plate, the second plate, and the edge cap. The cavity is configured to receive an insert, wherein the cavity is isolated from forces transmitted between the first plate and the second plate.

[0007] In an embodiment, the edge cap is configured to transfer shear forces between the first and second panels. An insert may be disposed within the cavity. The insert may be a thermally insulating insert, a fire-resistant insert, or a signal shielding insert. The insert may be a vacuum insulation panel. The insert may be bonded to the first or second panel. The insert may be encased in a non-combustible fabric to contain the contents of the insert and prevent burn-through.

[0008] In some embodiments, portions of the first panel, the second panel, and the edge cap can be thermoformed into an edge profile. Portions of the first skin, the second skin, the third skin, and the fourth skin can be bonded together to form the edge profile. The edge profile can include an arched section. The edge profile can include a flat edge section.

[0009] In some embodiments, the first skin has a first thickness and the second skin has a second thickness different from the first thickness.The first skin may have a first composition and the second skin may have a second composition different from the first skin.

[0010] In another embodiment of the present disclosure, a cargo container includes a first panel and a second panel disclosed and described herein. The first panel has a first edge portion, and the second panel has a second edge portion. The second panel is coupled to the first panel such that the first edge portion is adjacent to the second edge portion.

[0011] In an embodiment, the first edge portion is directly secured to the second edge portion. The cargo container may include a frame element disposed between the first edge portion and the second edge portion. The first edge portion and the second edge portion may both be directly secured to the frame element.

[0012] In another embodiment of the disclosure, a panel includes a first panel, a second panel, and a cap. The first panel includes a first core having a first skin bonded on a first side of the first core and a second skin bonded on a second side of the first core opposite the first side. The second panel includes a second core having a third skin bonded to a first side of the second core and a fourth skin bonded on a second side of the second core opposite the first side of the second skin. The cap is positioned between and bonded to the first panel and the second panel such that a cavity is defined by the first panel, the second panel, and the cap. The cap is configured to transfer shear forces between the first panel and the second panel.

[0013] In embodiments, the panel includes an insert disposed within the cavity. The insert can be isolated from shear forces of the first panel and the second panel. The first panel, the second panel, and the edge cap can be thermoformed to an edge profile.

[0014] In another embodiment of the disclosure, a method of manufacturing a panel includes positioning an end cap on a first panel, positioning a second panel on the end cap such that a cavity is defined by the end cap, and thermoforming a portion of the first panel, the second panel, and the end cap such that the first panel, the second panel, and the end cap are bonded together to form an edge profile of the panel. The first panel includes a first skin, a second skin, and a first core disposed between and bonded to the first skin and the second skin. The second panel has a third skin, a fourth skin, and a second core disposed between and bonded to the third skin and the fourth skin.

[0015] In embodiments, thermoforming the portion of the first panel, the second panel, and the end cap can include consolidating the first skin, the second skin, the third skin, and the fourth skin in the edge profile of the panel.

[0016] Further, to the extent consistent, any embodiment or aspect described herein can be used in combination with any or all other embodiments or aspects described herein. BRIEF DESCRIPTION OF DRAWINGS

[0017] Various aspects of the disclosure are described below with reference to the accompanying drawings, which are incorporated in, and constitute a part of, this specification, wherein:

[0018] Figure 1 is a cutaway perspective view of a structural panel provided in accordance with an embodiment of the disclosure;

[0019] Figure 2 is a cutaway perspective view of a structural panel provided in accordance with an embodiment of the disclosure;

[0020] Figure 3 is a cutaway perspective view of a first edge profile of the structural panel of Figure 2 ​

[0021] Figure 4 are two structural panels 100, 200 directly secured to each other without a frame Figure 3 is a cutaway perspective view of a second edge profile of the structural panel 200 of

[0022] Figure 5 is a cutaway perspective view of a second edge profile of the structural panel 200 of Figure 2

[0023] Figure 6 are two structural panels 100, 200 directly secured to each other without a frame Figure 5 is a cutaway perspective view of a second edge profile of the structural panel 200 of

[0024] Figure 7 is a flowchart of a method of manufacturing a structural panel according to an embodiment of the present disclosure; and

[0025] Figure 8 is a flowchart of a method of assembling a structure provided according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0026] The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the present disclosure are shown. Like reference numerals or characters can be used to denote like elements throughout the several views, if any. These exemplary embodiments are described so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. Features from one embodiment or aspect can be combined with features from any other embodiment or aspect in any appropriate combination. For example, any individual or collective features of method aspects or embodiments can be applied to device, product, or component aspects or embodiments, and vice versa. The present disclosure can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. As used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Further, although reference can be made herein to quantitative measures, values, geometric relationships, and the like, any one or more of these quantitative measures, values, geometric relationships, and the like, if not all, can be absolute or approximate, to account for acceptable variations that can occur, e.g., due to manufacturing or engineering tolerances, and the like, unless otherwise specified.

[0027] ​As used in the specification and the appended claims, the phrase "unit load device" (ULD) or "air cargo container" is defined as a container used to load baggage, cargo, mail, and the like on aircraft, including wide-body aircraft and narrow-body aircraft. While the containers described herein relate to ULDs used with aircraft, it is contemplated that cargo containers including the disclosed vacuum insulated panels can be used with other transportation vehicles, such as trucks, trailers, ships, or trains, such that the use with aircraft should not be considered limiting. Additionally, while the panels described herein are described with respect to forming air cargo containers, it is contemplated that the panels described herein can be used with other transportation vehicles or as structural panels for construction, such as interior or exterior walls, refrigerator panels, and the like. As used herein, the term "vacuum" refers to a pressure of 3 x 10 3 Pa or less.

[0028] The temperature of the cargo within a ULD designed with insulation properties can extend the time that the cargo can maintain a desired internal temperature. The desired internal temperature can be higher or lower than the ambient temperature. In particular, while the aircraft is idle on the ground waiting for takeoff, during flight, and while the aircraft is being unloaded. Additionally, the insulated ULD can maintain an internal temperature range by reducing the amount of passive temperature control material (e.g., dry ice) or reducing the size of active cooling / heating equipment (e.g., refrigeration / heating equipment).

[0029] Referring now to Figure 1 , a structural panel according to an embodiment of the disclosure is provided, which is generally referred to as panel 20. Panel 20 can be a thermoplastic panel that is capable of forming different shapes under the action of heat and pressure. Panel 20 is a composite panel that includes a top or first skin 22, a core 24, and a bottom or second skin 26 that are bonded together to form a sandwich panel. First skin 22 and bottom skin 26 can be fiber-reinforced thermoplastic resin. The fibers of first skin 22 and / or bottom skin 26 can include thermoplastic fibers, such as glass fibers, carbon fibers, aramid fibers, ceramic fibers, other fibers typically used in composite construction, or combinations thereof. The resin of first skin 22 and / or bottom skin 26 can be a thermoplastic resin, such as polypropylene, polyester, nylon, polyetherimide (PEI), polyether ether ketone (PEEK), or other thermoplastic resins used in the composite industry.

[0030] The skins 22, 26 can be the same or can be different. For example, the first skin 22 can have a greater or lesser thickness than the second skin 26. Additionally or alternatively, the fibers and / or resins of the first skin 22 and the second skin 26 can be the same or different from one another. The first skin 22 and the second skin 26 can differ based on the final position of the skins 22, 26 in the final panel assembly as described in detail below. For example, the first skin 22 can be configured to be exposed to external elements, and the second skin 26 can be configured to be an inner layer protected from external elements, as described in detail below. In some embodiments, the first skin 22 or the second skin 26 can include glass fibers and polypropylene resin, where the glass fibers can make up 64% of the weight of the respective skin 22, 26.

[0031] In certain embodiments, the first skin 22 and the second skin 26 can include glass fibers, aramid fibers (including Kevlar fibers), ultra-high molecular weight polyethylene (UHMWPE) fibers, carbon fibers, polypropylene fibers, or various mid- to high-modulus fibers. The fibers forming the first skin 22 or the second skin 26 can be woven into cloth or laid up into unidirectional layers. The thickness of the first skin 22 or the second skin 26 can be in the range of 0.05 mm to 3 mm, for example, in the range of 0.5 mm to 1 mm. In certain embodiments, the first skin 22 or the second skin 26 can have a thickness greater than 3 mm. The thickness of the first skin 22 or the second skin 26 can be optimized based on structural strength, impact resistance, weight, and cost.

[0032] For example, a glass fiber / polypropylene skin with a thickness of 0.4 mm has been tested and proven to handle the structural loads required for a ULD panel when properly designed and manufactured. A skin with a thickness of 0.4 mm can provide superior weight and cost. During use, a ULD panel and the skins forming the ULD panel can be impacted by a forklift tine. Controlling such impacts and avoiding damage requiring repair is a key requirement for panels used in ULDs. A skin with a thickness of 0.4 mm can outperform aluminum commonly used in this application. Since one of the goals of such product construction is to minimize operational costs and minimize downtime, calculations can be performed to optimize impact resistance along with weight and cost (assuming structural requirements are met). The thickness of the impact-facing skin can be increased to absorb higher impact forces without visible damage.

[0033] As described above, the panel 20 can be thermoformed and pressure formed into different shapes. During the forming process, the fibers of the skins 22, 26 can wrinkle instead of stretch. This wrinkling can reduce the compressive strength of the respective skin 22, 26, and thus the panel 20 as a whole. Accordingly, the geometry of the fibers of the skins 22, 26 can be designed to account for the subsequent forming processes as described in detail below. The orientation or geometry of the fibers of the skins 22, 26 can depend on the location within the skin 22, 26. For example, the fibers of adjacent edges can have perpendicular orientations to one another, with the opposite edges having similar orientations.

[0034] The core 24 provides compressive strength and can increase the durability of the panel 20. The core 24 is designed to have a shear strength and compressive strength sufficient to transfer loads between the first skin 22 and the second skin 26. The core 24 can be a foam core, a honeycomb core, or a foam-filled thermoplastic honeycomb core. In comparison to a foam core, a honeycomb core can provide increased shear strength or compressive strength, which can have a lower insulating value relative to a foam core. A foam-filled honeycomb core can provide the strength of a honeycomb core and an insulating value close to that of a full foam core. In some embodiments, the core 24 includes a closed-cell foam. In embodiments in which the core 24 includes a foam, the density of the foam can be selected to balance the structural strength of a denser foam with the insulating value of a less dense foam. The foam used to form the foam core can balance the strength requirements of the core 24 with the weight of the core 24. This balance can be important in applications in which the weight of the entire panel 10 is important, such as when the panel is used to form a ULD or other panel used in an aircraft or watercraft. While a denser foam can provide greater structural strength, a denser foam can have a lower insulating value. In particular embodiments, the core 24 includes a closed-cell polypropylene foam having a density of 64 kg / m3. 3

[0035] In embodiments, the thickness of the core 24 can vary between 6 mm and 75 mm. In some embodiments, the core 24 can have a thickness less than 6 mm or greater than 75 mm. The thickness of the core 24 can be increased to provide an improved insulating value. The thickness of the core 24 can be decreased to improve the transfer of shear loads between the skins 22, 26, such that a thin core 24 can create a rigid and strong composite sandwich panel. As the thickness of the core 24 increases, the shear modulus of the core 24 can increase to effectively transfer shear forces between the skins 22, 26. To increase the shear modulus of the core 24, the density of the core 24 can be increased. Increasing the density of the core 24 can decrease the insulating value of the core 24 and increase the weight of the core 24. While a decrease in the insulating value of the core or an increase in the weight of the core can be undesirable. Methods of optimizing the thickness of the core 24 are discussed in more detail below. ​

[0036] The first skin 22 and the second skin 26 are bonded to the core 24 such that shear loads are transferred between the skins 22, 26 by the core 24. The core 24 can be sandwiched between the first skin 22 and the second skin 26 under pressure and / or heat to form the panel 20. The bond between the skins 22, 26 prevents delamination, which would result in a significant reduction in the stiffness of the panel 20. In embodiments in which the core 24 includes foam, the foam of the core 24 can be compatible with the resin of the first skin 22 or the second skin 26 such that the bond between the skins 22, 26 is of sufficient strength.

[0037] Reference Figure 2 A structural panel according to embodiments of the present disclosure is provided, generally referred to as panel 100. The panel 100 includes a first panel 120, a second panel 220, and a central core 150 positioned between the first panel 120 and the second panel 220. The first panel 120 and the second panel 220 are each structural panels having a first skin 122, 222, a second skin 126, 226, and a core 124, 224, as described in detail above with respect to the panel 20.

[0038] The central core 150 includes an end portion or cap 160 that extends along an outer edge of the central core 150 and is bonded to the opposing skins 126, 222 of the first panel 120 and the second panel 220. The cap 160 is formed of a thermoplastic foam. The thermoplastic foam of the cap 160 can be compatible with the resin of the inner skins 126, 222 of the first panel 120 and the second panel 220 such that the cap 160 is structurally bonded to the first panel 120 and the second panel 220. Additionally, the thermoplastic foam of the cap 160 can have one or more properties similar to the foam of the cores 124, 224 of the first panel 120 and the second panel 220. For example, the foam of the cap 160 can have a melt rate similar to the cores 124, 224.

[0039] The central core 150 includes a cavity 170 defined by the second skin or inner skin 126 of the first panel 120, the first skin or inner skin 222 of the second panel 220, and each of the caps 160. The caps 160 are bonded to the first panel 120 and the second panel 220 such that shear forces and compressive forces are transmitted between the first panel 120 and the second panel 220 through the caps 160. The caps 160 can allow all of the shear forces and compressive forces to be transmitted between the first panel 120 and the second panel 220, with the cavity 170 isolated from the shear forces and compressive forces experienced by the first panel 120 or the second panel 220. The construction of the first panel 120 and the second panel 220 provides structural strength to the panel 100. Additionally, the stiffness of the first panel 120 and the second panel 220 prevents the individual panels 120, 220 from bending or "oil-canning." For example, in contrast to a panel having only a single skin on the interior or exterior of the panel, the inner and outer skins of the first panel 120 and the second panel 220 can provide additional strength that prevents bending.

[0040] The panel 100 can include a thermally insulating insert 180 disposed within the cavity 170. The thermally insulating insert can be formed of a less dense foam than the cap 160 such that the insert 180 has a greater insulating value than the cap 160. In some embodiments, the insert 180 can be a vacuum insulated panel (VIP). An example VIP panel 280 can include a filler material 282 and a barrier or envelope 284. The filler material 282 can be a porous fabric or a porous foam material. The envelope 284 is disposed on the filler material 282 such that the filler material 282 is hermetically sealed inside the VIP 280. The envelope 284 can be a thin, impermeable layer of metal, such as aluminum. During manufacture of the VIP 280, a vacuum is applied such that a vacuum is maintained within the envelope 284 when the envelope 284 is sealed on the filler material 282. The filler material 282 prevents the envelope 284 from shrinking and maintains the volume within the envelope 284. The VIP 280 can have an R-value higher than R-15 per inch of thickness, such as an R-value of R-20, R-30, R-40, R-45, or R-50 per inch of thickness. By isolating the VIP 280 within the cavity 170, the VIP 280 is protected from the first panel 120 and the second panel 220 to prevent the seal of the envelope 284 from being compromised and thus the VIP 280 from losing its vacuum. In some embodiments, the VIP 280 can include a vacuum port 286 that allows for the vacuum to be drawn in the VIP 280. In certain embodiments, the VIP 280 includes a vacuum indicator 288 that provides an indication of the vacuum within the VIP 280. In particular embodiments, the vacuum port 286 and / or the vacuum indicator 288 can be accessed through the first panel 120 or the second panel 220. Examples of VIPs, including VIPs with vacuum ports and vacuum indicators, are disclosed in U.S. Patent Publication No. 2020 / 0407149, which is incorporated by reference herein in its entirety.

[0041] In certain embodiments, the envelope 284 can be formed of a non-combustible material or fabric. Such non-combustible material can improve the fire resistance capabilities of a panel including the VIP 280. The non-combustible material can be a quartz fabric or other high-temperature fabric. The non-combustible material can be a fabric that covers or encapsulates the VIP 280 to provide an impermeable fire barrier. In embodiments, the VIP 280 can be formed of fireproof silica or fiberglass. However, the VIP 280 can lose structural integrity when exposed to fire. The envelope 284 that surrounds the VIP 280 can contain the material of the VIP 280 when exposed to fire to prevent the VIP 280 from being destroyed, which can otherwise be destroyed when exposed to fire. The envelope 284 can encapsulate the VIP 280 to contain the contents of the insert and prevent burn-through.

[0042] Additionally or alternatively, the panel 100 can include other inserts disposed within the cavity 170. For example, the panel 100 can include a fire resistant insert or a signal shielding insert. Because the inserts within the cavity 170 are non-structural, a variety of different inserts can be disposed within the panel 100 to improve the properties of the panel or to add functionality to the panel 100. In certain embodiments, the insert for the cavity 170 can be a solid insert made of a thermally insulating material (e.g., phenolic resin, fiberglass, or similar material with high compressive strength). In some embodiments, the insert can include attachment points as desired. In particular embodiments, a VIP panel can be formed with holes such that this type of insert can be used as an attachment point. In certain embodiments, the attachment insert can be located within the core 124, 224.

[0043] With continued reference to Figure 2 A method of optimizing skin thickness is disclosed in accordance with the present disclosure. The method can include determining the thickness of the outboard facing skin 226 to be the thickest to resist impacts from a forklift tine, e.g., high speed impacts from a forklift tine. The thickness of the inboard facing skin (e.g., skin 122) can be thinner than the thickness of the outboard facing skin 226 because the inboard facing skin 122 can be subjected to impacts from cargo pallets and low speed forklift tines as compared to high speed forklift tines. Because the skins 126 and 222 are disposed on the interior of the panel and thus will be subjected to the lowest impacts, the inner skins 126 and 222 can have a thickness that is less than the skins 122 and 226. The inner skins 126, 222 can provide a layer of tension across the core 124 and 224 to create a structurally rigid sandwich composite panel. The thickness of the skins 122, 126, 222, 226 can be selected to have sufficient stiffness relative to the shear strength of the foam to resist buckling during bending. For example, the outboard facing skin 226 can have a thickness of 1.5 mm, the inboard facing skin 122 can have a thickness of 0.7 mm, and both inner skins 126, 222 can have a thickness of 0.4 mm. In some applications, this construction can address structural, impact, weight, and cost considerations simultaneously.

[0044] In some embodiments, the method can include optimizing the thickness of the core 124, 224 based on the structure of the panel 100 and the impact scenario. In some embodiments, the filler material 282 and the cap 160 can be optimized for weight, cost, and thermal insulation value. The panel 100 can be configured such that a majority of the structural load of the panel is carried by the two outer panels 120, 220, such that the filler material 282 and the cap 160 can be configured to increase the thermal insulation value of the panel 100 and / or provide sufficient compressive strength to avoid deformation or buckling of the panels 120, 220. The filler material 282 can be a vacuum insulated panel to provide a high thermal insulation-weight / thickness ratio, and the cap 160 can be expanded or extruded polypropylene foam to provide a durable and formable and have a lower but still effective thermal insulation value.

[0045] With additional reference to Figure 3 The panel 100 can include one or more shaped edge portions, with an exemplary shaped edge portion 110 shown. The first panel 120, the second panel 220, and the cap 160 are formed from a thermoplastic material that allows for thermoplastic shaping of the edge portion 110 of the panel 100. As shown, the shaped edge portion 110 is formed by heat shaping portions of the first panel 120, the second panel 220, and the cap 160 along an edge of the panel 100 under heat and pressure. The shaped edge portion 110 is compressed to have an angled section 112 and a profiled section 116. In the angled section 112, the first panel 120, the second panel 220, and the cap 160 are compressed toward the outer skin or second skin 226 of the second panel 220, such that the thickness of the panel 100 substantially linearly decreases as the panel 100 extends toward the edge of the panel 100. The profiled section 116 extends from the angled section 112 to form a terminal edge 118 of the panel 100. The profiled section 116 can have a substantially constant thickness and form various shapes. As shown, the profiled section 116 has an arched profile. By heat shaping the edge portion 110 of the panel 100, the bond between the first panel 120, the second panel 220, and the cap 160 can be enhanced or formed. For example, the skins of the panels 120, 220 can be consolidated during shaping of the profiled section 116. The edge portion 110 can create a shear layer between the first panel 120 and the second panel 220, such that the panels 120, 220 act in concert with one another and have high stiffness. This high stiffness can be enhanced at or near the edge portion 110.

[0046] With additional reference to Figure 4The edge portions 110 of adjacent panels 100 can be configured to fit together. The edge portions 110 of adjacent panels 100 can overlap one another such that fasteners can pass through the edge portions 110, and in particular, the profiled sections 116 of the edge portions 110, to secure the edge portions 110 together. The fasteners can be selected from, but are not limited to, rivets, locking bolts, or threaded fasteners. As shown, the edge portions 110 are joined together at a 90 degree angle. However, the angle between the panels 100 can be any angle, so long as the edge portions 110 are compatible with one another. As such, although Figure 4 the edge portions 110 shown are identical, it is contemplated that edge portions 110 having different shapes can be compatible with one another and can be joined together in a similar manner to form corners with or without a frame.

[0047] As Figure 4 shown, the panels 100 can be joined together without the use of a frame. Allowing the panels 100 to be joined together without a frame can increase the useful life of the container, as rigid frame members can be susceptible to damage. The shape and material of the edge portions can provide a durable and resilient corner that can withstand impacts that cargo containers, including ULDs, are subjected to in common use. In some embodiments, the profiled sections 116 can be provided around a frame.

[0048] Referring now to Figure 5 and Figure 6 , a panel 100' having a flat profiled edge portion 110' is shown. The panel 100' is similar to the panel 100, and therefore for the sake of brevity, only the differences will be described in detail here. The flat profiled edge portion 110' has an angled section 112' and a profiled section 116'. The profiled section 116' is substantially flat and extends from the outer skin 122 of the first panel 120 such that the outer surface 117' of the profiled section 116' and the outer surface of the outer skin 122 are substantially planar.

[0049] The profiled section 116' can be shaped to secure to a frame member 310, as Figure 6The frame members 310 can be pultrusions, metallic or non-metallic, whose profile supplements and fills the area between the edge portions 110 of adjacent panels 100'. In some embodiments, the frame members 310 are formed of fiberglass protrusions. Such pultrusions can be made of 60-80% glass fiber by weight with polyurethane, polyester resin, or vinyl ester resin. Such pultrusions can have a lower thermal transfer constant than other structural materials, and thus can reduce heat transfer through the frame members 310. The pultrusions can allow both the panels and the frame to be resilient, to allow for deformation and recovery from impacts. In certain embodiments, the frame members 310 can be extruded aluminum or other conductive material. The frame members 310 can have rigid corner elements 316' configured to be exposed to form a corner of a container or structure. The frame members 310 can be hollow and filled with a thermally insulating material 318 such as foam or aerogel. The contoured sections 116' of the panels 100' are secured directly to the frame members 310, such that the panels 100' are secured together. The contoured sections 116' can adhere, bond, or fasten to the frame members 310. For example, fasteners can pass through the contoured sections 116' and into the frame members 310. The fasteners can be blind rivets that pass through the contoured sections 116' and into the frame members 310.

[0050] Referring now to Figure 7 , a method for manufacturing a panel according to embodiments of the present disclosure is provided, and reference is made to Figures 1-6 the panel 100, 100' as a whole. To manufacture a panel, such as the panel 100, a first structural panel 120 having a first skin or outer skin 122, a core 124, and a second skin or inner skin 126 is positioned such that the outer skin 122 faces downward (step 530). At or near the edges of the first structural panel 120, one or more caps 160 are positioned on the inner skin 126 of the first structural panel 120 (step 540). The one or more caps 160 can be separate pieces of foam arranged to form the cavities 170 therebetween. Alternatively, the caps 160 can be a single piece of foam or a monolithic piece of foam, with the cavities 170 cut out of it. In particular embodiments, the method 500 includes positioning a single piece of foam or multiple pieces of foam around the edges of the first structural panel 120 and cutting the cavities 170 from the single piece of foam or multiple pieces of foam (step 544). In some embodiments, the positioning of the caps 160 includes bonding the one or more caps 160 to the inner skin 126 with an adhesive or adherent (step 546).

[0051] In cases where the one or more caps 160 are positioned or adhered to the inner skin 126 of the first structural panel 120, an insert can be disposed within the cavity 170 (step 550). The insert can be a thermally insulating insert (e.g., the thermally insulating insert 180, a VIP panel 180), a fire resistant insert, an attachment insert, a solid insert, or a signal shielding insert. In some embodiments, the method 500 can include extending through the first structural panel 120 or the one or more caps 160 into a passageway (step 554). The passageway can provide access to one or more ports of the insert. For example, the passageway can provide access to a vacuum port of a VIP panel, an indicator of the insert, an antenna of the insert, or electronics of the insert. In certain embodiments, the insert can be adhered to the inner skin 126 of the first structural panel 120 or the one or more caps 160 (step 556).

[0052] In cases where the insert is disposed within the cavity 170, a second structural panel 220 having a first or outer skin 222, a core 224, and a second or inner skin 226 is positioned such that the inner skin 226 opposes the inner skin 126 of the first structural panel 120 (step 560). The second structural panel 220 is positioned such that the outer skin 222 opposes the outer skin 122 of the first structural panel 120, with the insert disposed between the first structural panel 120 and the second structural panel 220. The inner skin 226 can be adhered to the one or more caps 160 with an adhesive or an adhesive agent (step 562). In certain embodiments, the inner skin 226 can be adhered to the insert within the cavity 170 (step 566). For example, an elastomeric layer or structural glue can be used to adhere the insert to the inner skins 126, 226. Adhering the insert to one or more of the inner skins 126, 226 can reduce movement of the insert within the cavity 170. Reducing movement of the insert within the cavity 170 can reduce wear between the insert and surfaces defining the cavity 170 (e.g., the inner skins 126, 226 and the caps 160). Adhering the insert to one or more of the inner skins can provide additional shear strength to the panel 100.

[0053] When the first structural panel 120 and the second structural panel 220 are positioned relative to each other such that the one or more caps 160 and the insert are sandwiched between the first structural panel 120 and the second structural panel 220, the edges of the first structural panel 120 and the second structural panel 220 are thermoformed to shape the edge portion 110 of the panel 100 and to bond the first structural panel 120 to the second structural panel 220 (process 570). The edge portion 110 of the panel 100 can be thermoformed by heating the first mold and the second mold and pressing the edges of both the first structural panel 120 and the second structural panel 220 together to shape the edge portion 110 (step 572). The first mold and the second mold can be heated to a temperature and pressed together such that the first structural panel 120, the second structural panel 220, and the cap 160 sandwiched between the panels 120, 220 are melted and bonded together. During thermoforming, the skins of the panel 100 can slide relative to each other to form a new shape. As the new shape is formed, new bonds can be formed between the skins and the foam (e.g., the core 124, 224 and the cap 160). The density of the foam in the edge portion 110 can increase during thermoforming. For example, a foam with a density of 2% to 20% solid polymer can increase to a density of 80% to 100% during thermoforming. In one embodiment, a 64 kg / m 3 The 13 mm foam core of the foam is melted and compressed to a consolidated thickness of 0.93 mm. In another embodiment, a 63 mm thick panel is thermoformed to have a profiled section with a thickness of 5 mm. The compression and consolidation during thermoforming can increase the compressive strength of the edge portion and can allow for high fastener pull-out resistance.

[0054] Once the edge portion 110 is shaped, the mold can be allowed to cool or actively chilled such that the edge portion 110 consolidates or solidifies before being released from the mold (step 574).

[0055] As the edge portion 110 is shaped, the first structural panel 120, the second structural panel 220, and the cap 160 sandwiched between the panels 120, 220 are bonded together. As described in detail above, the materials forming the first structural panel 120, the second structural panel 220, and the cap 160 can be compatible with each other such that as the edge portion 110 is shaped, the first structural panel 120, the second structural panel 220, and the cap 160 are melted and bonded together. In some embodiments, as the edge portion 110 is shaped, the cavity 170 is sealed along the edge portion 110.

[0056] In the case of the edge portion 110 of the shaped panel 100, the panel 100 can be repositioned by rotating the panel or moving the mold such that another edge portion 110 of the panel 100 is positioned between the molds (step 576). The panel 100 can be rotated or the molds can be moved such that the edge portion 110 opposite or adjacent to the shaped edge portion 110 is disposed between the molds. With the unshaped edge portion 110 between the molds, the molds are heated and pressed together to shape the edge portion 110 in a manner similar to that described in detail above (steps 572 and 574). The rotation of the panel 100 or the movement of the molds and the shaping of the unshaped edge portion 110 is repeated until all of the edge portions 110 of the panel 100 are shaped. In some embodiments, one or more of the edge portions 110 are left unshaped. In some embodiments, all of the edge portions 110 are shaped to be the same profile. In certain embodiments, adjacent edge portions 110 are shaped to have different profiles from one another. In particular embodiments, opposite edge portions 110 are shaped to have different profiles from one another.

[0057] In certain embodiments, the method 500 includes forming a first structural panel 120 and a second structural panel 220 (process 510). Forming the first structural panel 120 and the second structural panel 220 includes sandwiching the core 24 between the first skin 22 and the second skin 26 (step 512). The core 24 is bonded to the first skin 22 and the second skin 26 such that the first skin 22 and the second skin 26 are able to transfer forces between them through the core 24 (step 514). The step of bonding the first skin 22 or the second skin 26 to the core 24 can be performed under heat and / or pressure to form a structural bond therebetween. The first skin 22 and the second skin 26 can be the same as one another in thickness, material, and composition, or the first skin 22 and the second skin 26 can be different from one another in thickness, material, or composition. Steps 512 and 514 can be used to form the first structural panel 120 and / or to form the second structural panel 220. The first structural panel 120 and the second structural panel 220 can be the same as one another or can be different from one another. In embodiments, the skins 22, 26 of each structural panel 120, 220 can be optimized for the location within the final panel 100. For example, the outer skin 122 of the first structural panel 120 can have a greater thickness than the inner skin 126 thereof. In some embodiments, the outer skin 122 of the first structural panel 120 can have a greater thickness than the outer skin 222 of the second structural panel 220. In certain embodiments, the inner skins 126, 226 have the same thickness, while in other embodiments, the inner skins 126, 226 can have different thicknesses.

[0058] Reference is made to Figure 8, a method for joining a first panel 100 to a second panel 100 is shown, generally referred to as method 600, in accordance with the present disclosure. Joining the panels 100 includes arranging or positioning the first panel 100 adjacent to the second panel 100 such that the edge portions 110 of each panel 100 are adjacent to one another (step 610). Positioning the panels 100 can include overlapping the edge portions 110 of the panels 100 such that fasteners can be passed through the edge portions 110 of each panel 100 to secure the panels 100 to one another (step 612). In certain embodiments, joining the panels 100 can include placing a connector between the edge portions 110 (step 614) and securing the first panel 100 to the connector (step 616) and securing the second panel 100 to the connector (step 618) such that the panels are secured to one another. Step 610 can be repeated until a shipping container, truck bed, ULD, or structure is formed.

[0059] The panels described in detail herein can be configured to have structural features suitable for other applications, including for cargo containers on trucks, ships, or trains. Such cargo containers can be in the form of a trailer for a truck, a shipping container for a ship, or a railcar. Additionally, the panels described in detail herein can be suitable for use in buildings requiring insulated walls. For example, the panels described in detail herein can be suitable for use in exterior walls or as an insulating layer on the exterior surface of a wall. Additionally, the panels described in detail herein can be used to construct a refrigeration unit, such as those used in a hotel, restaurant, or laboratory environment. When an enclosure or container is formed from the panels described in detail herein, the enclosure or container can maintain an elevated or reduced temperature relative to the environment surrounding the enclosure or container while maintaining minimal energy transfer through the panels. Additionally, the panels described in detail herein can be used to add functionality to a structure without sacrificing the structure.

[0060] While several embodiments of the present disclosure have been shown in the drawings, it is not intended that the present disclosure be limited to this and it is intended that the present disclosure be as broad in scope as the art will allow and that the specification be read likewise. Any combination of the above- described embodiments can also be envisioned, which fall within the scope of the appended claims. Therefore, the above description should not be interpreted as limiting, but merely as exemplifications of particular embodiments. Other modifications can be assumed by those skilled in the art within the scope of the appended claims.

Claims

1. A panel comprising: a first panel comprising a first core sandwiched between and bonded to a first skin and a second skin; a second panel including a second core sandwiched between and bonded to a third skin and a fourth skin; and An edge cap is positioned between and bonded to the first and second plates such that a cavity is defined by the first and second plates and configured to receive an insert, the cavity being isolated from forces transmitted between the first and second plates.

2. The panel according to claim 1, wherein The edge cap is configured to transfer shear forces between the first plate and the second plate.

3. The panel of claim 1, further comprising an insert disposed within the cavity.

4. The panel according to claim 3, wherein The insert is an insulating insert, a fire-resistant insert or a signal shielding insert.

5. The panel according to claim 4, wherein The insert is a vacuum insulation panel.

6. The panel according to claim 3, wherein The insert is bonded to the first plate or the second plate.

7. The panel according to claim 3, wherein The insert is encased in non-combustible fabric to contain the contents of the insert and prevent burn-through.

8. The panel according to claim 1, wherein Portions of the first plate, the second plate, and the edge cap are thermoformed to an edge profile.

9. The panel according to claim 8, wherein Portions of the first skin, the second skin, the third skin, and the fourth skin are bonded together to form an edge profile.

10. The panel according to claim 8, wherein The edge profile includes an arched section or a flat edge section.

11. The panel according to claim 1, wherein The first skin has a first thickness, and the second skin has a second thickness different from the first thickness.

12. The panel according to claim 1, wherein The first skin has a first composition and the second skin has a second composition different from the first skin.

13. A cargo container comprising: a first panel, the first panel being the panel according to claim 1, the first panel having a first edge portion; and A second panel, the second panel being the panel of claim 1, the second panel having a second edge portion, the second panel being joined to the first panel such that the first edge portion is adjacent to the second edge portion.

14. The cargo container according to claim 13, wherein: The first edge portion is directly secured to the second edge portion.

15. The cargo container of claim 13, further comprising a frame member disposed between the first edge portion and the second edge portion, the first edge portion being directly secured to the frame member, and the second edge portion being directly secured to the frame member.

16. A panel comprising: a first panel comprising a first core having a first skin bonded to a first side of the first core and a second skin bonded to a second side of the first core, the second side of the first core being opposite the first side of the first core; a second panel comprising a second core having a third skin bonded to a first side of the second core and a fourth skin bonded to a second side of the second core, the second side of the second core being opposite the first side of the second core; and A cap is positioned between and bonded to the first and second plates such that a cavity is defined by the first and second plates and the cap is configured to transfer shear forces between the first and second plates.

17. The panel of claim 16, further comprising an insert disposed within the cavity, the insert being isolated from shear forces of the first and second plates.

18. The panel according to claim 16, wherein The first plate, the second plate, and the cap are thermoformed to edge contours.

19. A method of manufacturing a panel, the method comprising: positioning an end cap on a first panel, the first panel having a first skin, a second skin, and a first core, the first core being disposed between and bonded to the first skin and the second skin; positioning a second panel on the end cap such that a cavity is defined by the end cap, the first panel, and the second panel, the second panel having a third skin, a fourth skin, and a second core, the second core being disposed between and bonded to the third and fourth skins; and A portion of the first plate, the second plate, and the end caps are thermoformed so that the first plate, the second plate, and the end caps are bonded together to form an edge profile of the panel and the cavity is isolated from forces transmitted between the first plate and the second plate.

20. The method according to claim 19, wherein Thermoforming a portion of the first panel, the second panel, and the end cap includes consolidating the first skin, the second skin, the third skin, and the fourth skin in the edge profile of the panel.

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