Reconfigurable Rigid Structures

Abstract

Described herein is a reconfigurable structure that can rapidly transition from a flexible configuration to a rigid configuration. A core layer, a face sheet layer, and an outer sealed layer form the reconfigurable structure. The reconfigurable structure can transition from a flexible configuration to a rigid or stiff configuration, for example, by applying a vacuum or pressure to the sealed structure. With the vacuum or pressure removed, the layers can easily slip or move relative to each other. With the vacuum or pressure applied, the layers can transition to a state that exhibits a significantly increased ability to resist slippage, movement, bending, and buckling, thereby stiffening into a rigid configuration.

Description

[Technical field]

[0001] Claiming priority

[0001] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 296,478, entitled "RECONFIGURABLE STRUCTURES," filed on January 4, 2022, which is incorporated by reference in its entirety into this specification.

[0002] Incorporation by Reference

[0002] All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

[0003]

[0003] This application relates to the field of reconfigurable structures that can be transitioned from a flexible configuration to a rigid configuration. [Background technology]

[0004] Fields of use

[0004] Cylindrical rigidizing devices (e.g., tubes, rods, etc.) have been described for use in navigating tortuous anatomical structures, such as (but not limited to) the gastrointestinal tract, biliary pancreatic duct, vascular system (including cardiac, peripheral, pulmonary, and neurovascular systems), and airways. Such elongated devices can rapidly transition from a flexible configuration (i.e., a relaxed, pliable, or soft configuration) to a rigid configuration. These devices may include multiple layers, such as coiled or reinforced layers, slip layers, braided layers, other rigidifying layers, bladder layers, and / or sealing sheaths. Application of vacuum or pressure allows these devices to transition from a flexible to a rigid configuration, including a generally tubular configuration, but also a rod (solid cylindrical) configuration.

[0005]

[0005] Existing non-tubular structures with reconfigurable shapes include those with complex or expensive design and / or manufacturing methods. For example, materials have been described recently that include sheets of cross-linked structures such as rings, cubes, and octahedra. These (usually 3D printed) materials are designed to be able to jam under compression and tension. Other rigidification materials include controlled shapes by embedding networks of thermoresponsive liquid crystal elastomers (LCEs), or thin strips of polymer that contract when heated. These LCEs contain stretchable heating coils that can be charged with an electric current, which heats the LCEs and causes them to shrink. As the LCEs shrink, they pull the flexible material into the pre-designed solid shape in which they are embedded and compressed. Particle jamming rigidification techniques have also been described extensively. Summary of the Invention [Problem to be solved by the invention]

[0006]

[0006] There is a need for a reconfigurable structure that has a simple, reliably constructed configuration and can provide a constant cross-sectional thickness and low material mass. It would also be useful to provide rigidified and reconfigurable structures that can be used without requiring significant electronics. [Means for solving the problem]

[0007]

[0007] Described herein are apparatus (e.g., systems and devices, including structural systems) that can be selectively rigidified and "stiffened" or releasably locked from a soft, foldable, flexible sheet configuration that can conform or deform to a desired shape into a structure that is rigid and rigid. Also described herein are methods of using these apparatus. These apparatus may be used as medical devices and for non-medical uses including, for example, housing, buildings, or evacuation shelters that can be easily compacted and quickly assembled. In general, these apparatus may be used for any component that would benefit from being transformed from a flexible sheet into a rigid structure.

[0008]

[0008] For example, the present specification describes a rigidizable shell structure comprising a flexible core layer, a first shear reinforcement layer disposed on a first side of the flexible core layer, a first face sheet adjacent to the first shear reinforcement layer, a second shear reinforcement layer disposed on a second side of the flexible core layer opposite the first side of the flexible core layer, a second face sheet adjacent to the second shear reinforcement layer, and an outer cover sealed around the flexible core layer, the first shear reinforcement layer, the first face sheet, the second shear reinforcement layer, and the second face sheet, wherein an inlet disposed within the outer cover is configured to permit application of pressure into the sealed housing, the first face sheet and the second face sheet being configured to shear relative to the flexible core layer in a first configuration in which the first face sheet and the second face sheet are flexible without the application of pressure, and the first face sheet and the second face sheet are pressure fixed to the core layer in a second configuration in which the first face sheet and the second face sheet are rigid under the application of pressure.

[0009]

[0009] The pressure may be a negative pressure.

[0010] In some examples, the flexible core layer includes Nomex or aluminum honeycomb.

[0011] In any of these examples, multiple core layers may be utilized. The core layer may comprise foam. The core layer may comprise scored wood (e.g., balsa wood). The core layer may be discontinuous. The core layer may comprise a thickness of about 0.1-10 cm, 0.5-10 cm, 0.1-5 cm, 0.5-5 cm, 0.5-2 cm, 1-5 cm, 1-10 cm, 2-10 cm, 2-8 cm, 2-5 cm, 3-10 cm, 3-8 cm, 3-5 cm, 4-10 cm, 4-8 cm, 4-5 cm, or 5-10 cm. The core layer may comprise a density of about 0.0320-0.3203 g / cm 3 (2-20lb / ft 3 ) may have a density between

[0012] The face sheet may include a woven or braided fiber fabric. In some examples, the face sheet comprises multiple layers of unidirectional fibers intermittently attached to one another. In some examples, the fiber fabric comprises a braid or weave angle of about 0-90°, 10-90°, 20-90°, 30-90°, 40-90°, 50-90°, 60-90°, 70-90°, 80-90°, 20-80°, 30-70°, 40-60°, 30-50°, or 40-50°. The braid angle may be the angle between adjacent fibers or fiber bundles.

[0013] The face sheet may include a thickness of about 0.1-5 cm, 0.5-5 cm, or 0.5-2 cm. The face sheet may have a coverage of about 30%-70%, such as 40%-60%, e.g., 30%, 40%, 50%, 60% or 70%. The face sheet may include tensile elements having a modulus of elasticity of about 1-400 GPa (e.g., about 10-200 GPa, 50-200 GPa, 50-100 GPa, 60-100 GPa, 70-100 GPa, greater than 100 GPa, greater than 200 GPa). The face sheet may have a modulus of elasticity of about 0.1-3 g / cm 3 , 0.1~2g / cm 3 , 0.1~4g / cm 3 , 0.1~5g / cm 3 , 0.1~6g / cm 3 , 0.1~7g / cm 3 , 0.1~8g / cm3 , 0.1~9g / cm 3 , 0.1~10g / cm 3 The face sheet may be comprised of a material having a density of 0.1 to 1.0 mm. The face sheet may include fibers that are rectangular, flat, round, and / or oval. The face sheet may include fibers that are plastic or metal. The face sheet may be comprised of monofilaments or small fiber bundles with up to 1000 fibers per bundle.

[0014]

[0014] The outer cover may include an elastomer. The outer cover may include a durometer of about 30A-80A, 40A-70A, or 50-60D. The outer cover may include a plastic. The outer cover may have a thickness of about 0.0001-1 inch, 0.001-1 inch, 0.005-1 inch, 0.01-1 inch, 0.05-1 inch, 0.01-0.5 inch, or 0.5-1 inch.

[0015] In both of these devices, the inlet is attached to a tube.

[0016]

[0016] Also described in this specification is a method of transitioning a shell structure from a flexible configuration to a rigid configuration, the method including the steps of setting the shell structure to a certain shape or position, where the shell structure includes a sealed outer layer surrounding a core layer disposed between a first face sheet and a second face sheet, the first face sheet and the second face sheet being configured to be shifted relative to the core layer and / or the shift reinforcement layer, and applying pressure to the shell structure through an inlet in the sealed outer layer, thereby pressure-fixing the first face sheet and the second face sheet to the core layer and rigidifying the shell structure in said shape or position.

[0017] Any of these methods may include applying pressure to the shell structure by applying a negative pressure (e.g., a vacuum) to the shell structure. Applying pressure to the shell structure may include applying a negative pressure of 0.01 to 14.7 psi to the shell structure. Any of these methods may include ceasing the application of pressure, thereby allowing the shell structure to transition back to the flexible configuration.

[0018] All of the methods and apparatus described in the present invention, in any combination, may be used to achieve the benefits contemplated and described herein.

[0019] A better understanding of the features and advantages of the method and apparatus described in this invention can be obtained by reference to the following detailed description and accompanying drawings that set forth exemplary embodiments. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 illustrates an example of a reconfigurable shell structure. [Figure 2A]

[0021] FIG. 1 illustrates an example of a reconfigurable shell structure shaped around a cylinder. [Figure 2B]

[0022] FIG. 2B shows the shaped shell structure of FIG. 2A supporting the weight of a cylinder. [Figure 3A]

[0023] FIG. 1 illustrates an example of a reconfigurable shell structure shaped around the end of a cylinder. [Figure 3B]

[0024] FIG. 3B shows the shaped shell structure of FIG. 3A supporting the weight of a cylinder. [Figure 4A]

[0025] FIG. 1 illustrates an example of a reconfigurable shell structure shaped around the end of a rod. [Figure 4B]

[0026] FIG. 4C shows the reconfigurable shell structure of FIG. 4B with the rods removed and the structure maintaining a tubular shape. [Figure 4C]

[0027] FIG. 4D shows the reconfigurable shell structure of FIG. 4C supporting the weight of a cylinder. [Figure 5A]

[0028] FIG. 1 is a schematic cross-sectional view of an example of a reconfigurable shell structure in a relaxed (non-rigidified, highly flexible) configuration. [Figure 5B]

[0029] FIG. 5B is a schematic cross-sectional view of the reconfigurable shell of FIG. 5A in a rigidified configuration. [Figure 5C]

[0030] 1 is a schematic cross-sectional view of another example of a reconfigurable shell in a relaxed (non-rigidified, highly flexible) configuration. [Figure 6A]

[0031] FIG. 5B is a cross-sectional view of another example of a reconfigurable shell structure in a relaxed (non-rigidified, highly flexible) configuration similar to that shown in FIG. 5A. [Figure 6B]

[0032] FIG. 6B is a cross-sectional view of another example of a reconfigurable shell structure in a relaxed (non-rigidified, highly flexible) configuration. The structure shown in FIG. 6B is formed of stacked layers of stacked core layers. [Figure 7A]

[0033] FIG. 1 illustrates an example of a braided plastic monofilament material layer that can be used as a face sheet in a reconfigurable shell structure. [Figure 7B]

[0034] 1A-1C show an example of a woven fiber fabric material layer that can be used as a face sheet in a reconfigurable shell structure. [Figure 8A]

[0035] 1A-1C illustrate embodiments of material layers that can be used as core layers in reconfigurable shell structures. [Figure 8B] 1A-1C illustrate embodiments of material layers that can be used as core layers in reconfigurable shell structures. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021]

[0036] Described herein are apparatus (e.g., systems and devices) that include planar sheets of material that can be controllably and rapidly transitioned from a highly flexible configuration (i.e., a relaxed, floppy, or soft configuration) to a highly rigid configuration (i.e., a configuration that is rigid and / or retains the shape it assumes when rigidified) by the application of negative pressure (e.g., vacuum). These apparatus may be referred to as rigidizable sheets and / or rigidizable shell structures.

[0022]

[0037] The structures described herein may rigidify quickly (e.g., nearly instantaneously, e.g., within less than 1 second, less than 0.5 seconds, less than 0.3 seconds, less than 0.2 seconds, less than 0.1 seconds, etc.). Larger structures may take longer to rigidify as their volume increases. They can be configured to rigidify quickly by including multiple pressure (e.g., suction) ports distributed within the structure.

[0023]

[0038] Generally, any of these structures can be translated in the direction of a planar surface without appreciable shrinkage.

[0024]

[0039] These devices may include a stack of layers sealed off by a sealed area in which a vacuum can be applied. The layers include one or more core layers, which are surrounded on both sides by shear-enhancing layers and by face sheets on the outside of the stack. The shear-enhancing layers may be optional and may not be included in some instances, for example where the face sheets can directly contact the core. The layers are stacked on top of each other and sealed off in sealed or sealable areas that are connected to one or more ports to which a vacuum (negative pressure) can be applied. In general, the layers can be freely slidable and flexible relative to each other in a relaxed configuration with little or no vacuum applied. When a negative pressure (e.g., vacuum) is applied, the stack can laminate together and dramatically increase the stiffness of the assembly. The stiffness can be adjusted by adjusting the magnitude of the negative pressure.

[0025]

[0040] Additionally, stiffness can be varied by tailoring the core, including increasing or decreasing the core thickness, the number of core layers, the characteristics of the face sheets, and / or the characteristics of the shear reinforcement layers. For example, increasing the thickness of the core layer (or increasing the combined thickness of all core layers) typically allows the structure to achieve a greater final stiffness, while decreasing the core thickness (or decreasing the combined thickness of all core layers) typically decreases the final stiffness for a significant pressure. The core layer may be divided into multiple core layers separated by a shear reinforcement layer (or multiple shear reinforcement layers). Adding additional core layers (and thus the overall thickness) can dramatically increase the final stiffness that can be achieved in the rigidized configuration without dramatically increasing the flexibility in the non-rigidized configuration. Thus, any number of core layers may be used. In general, increasing the core layer thickness can increase the final stiffness in the rigidized configuration for a significant negative pressure. The core layer (or region) may be divided into multiple core layers. In terms of thickness, having more (but thinner) core layers can increase flexibility without significantly compromising the stiffness of the stiffened core.

[0026]

[0041] In a non-rigidified configuration, the rigidifiable shell structures described herein can be highly malleable and can be readily formed into a three-dimensional surface or shape that can be rigidified by the application of negative pressure.

[0027]

[0042] Any suitable core sheet or layer may be used. In general, the core layer or sheet may be highly flexible in bending and has a well-defined thickness. The core provides a cross-sectional height that may be set or fixed. The core may have a solid surface, or a porous or honeycomb structure, and may be formed of any suitable material that allows bending flexibility while resisting compression. For example, the core may be formed of one or more materials and may be formed into a pliable structure, including, but not limited to, a honeycomb structure (e.g., Nomex™ or aluminum), a foam (e.g., sheet or scored with a back support matrix), or balsa wood (also typically scored with a back support matrix).

[0028]

[0043] The core may be formed of multiple layers, and as mentioned, each core layer may be separated from an adjacent core layer by a shear enhancing layer. Stacking multiple core layers may increase the base flexibility. Although the final stiffness may be related to the total thickness, dividing the core into constituent layers may allow for shear between the layers of the core, which increases flexibility.

[0029]

[0044] The face sheets are generally relatively lightweight, have high tensile stiffness, and may exhibit high shear stiffness, but may be formed into pliable layers. For example, the face sheets may be formed of woven, knitted, or braided layers or materials. For example, the face sheets may be formed of a fiber fabric (without a rigidifying resin). The fabric may be, for example, woven or braided, and may be formed of fibers, high strength fibers, plastics, or metals, or some combination thereof, such as fiber / epoxy laminates, aluminum steel or stainless steel, etc. The face sheets may be formed of fibers of material with angles, thicknesses, open area, elastic modulus, fiber diameters, and / or weaves that may be adjusted or selected to maximize the rigidity of the device in its rigidized configuration, while maximizing its flexibility in its relaxed configuration. Generally, the face sheets may be highly flexible in the relaxed configuration, but when suction is applied, the face sheets may be laminated against the core layer to form a structure that is extremely rigid.

[0030]

[0045] Any suitable shear enhancing layer may be used that can transfer load from the face sheets to the core, thus increasing the rigidified stiffness. For example, the shear enhancing layer may be formed of an elastomeric material having a variety of different durometers or thicknesses that may be set to optimize flexibility in the relaxed configuration while maximizing stiffness in the rigidified configuration of the device.

[0031]

[0046] The sealed structure (e.g., sealable housing) may be formed of a flexible, air-impermeable material, such as a plastic or elastomeric material. The sealed or sealable housing may hold the component layers inside the sealed structure so that application of a vacuum (negative pressure) causes the face sheets to suction against the core, resulting in internal fiber shear stabilization of the face sheets as they pressure-lock the face sheets to the core. When the pressure (vacuum) is released, the fibers forming the face sheets are free to slip relative to each other, the face sheets are no longer suctioned to the core, and the unit returns to its ultra-flexible form.

[0032]

[0047] Thus, multiple layers (e.g., core layers, face sheet layers, shear enhancement layers, and bladder layers and / or sealed outer layers) together can form a reconfigurable structure. The reconfigurable structure can be transitioned from a flexible configuration to a rigid or stiff configuration, for example, by applying a vacuum or pressure to the sealed structure. With the vacuum or pressure removed, the layers can easily shear or move relative to one another. With the vacuum or pressure applied, the layers can transition to a state that exhibits a greatly enhanced ability to resist shear, movement, bending, and buckling, thereby resulting in rigidification.

[0033]

[0048] FIG. 1 illustrates one embodiment of a reconfigurable structure 100. The structure 100 includes a sealed region 102. The sealed region includes an inlet 106 that is fluidly connected to a vacuum / pressure line 104. In the absence of applied pressure or vacuum, the structure 100 is flexible and can be bent or curved into a variety of different configurations. The example shown in FIG. 1 illustrates a single port or inlet to the vacuum / pressure line 104. In practice, multiple inlet pressure lines and / or outlet lines may be included. For example, a single device may include multiple regions that are selectively separable and rigidizable. The inlet and / or outlet lines may be valved or otherwise sealable. In FIG. 1, the periphery of the device is not part of the rigidizable structure. In some examples, other subregions of the device may not be rigidizable but may remain flexible. In some examples, all of the device may be rigidizable.

[0034]

[0049] Referring now to Figure 2A, an example of a reconfigurable device (e.g., structure 100 similar to that shown in Figure 1) is shown bent around a cylinder 202. In the absence of application of pressure or vacuum, the device (e.g., structure 100) is flexible enough to bend in this manner. After application of pressure or vacuum while bent around a cylinder, structure 100 is rigidified into its assumed shape, as shown by the reconfigured shape in Figure 2B. Figure 2B also shows that the rigidified structure 100 is strong enough to withstand the weight of the cylinder.

[0035]

[0050] Figure 3A shows reconfigurable structure 100 wrapped around the end of a cylinder 202. In the absence of application of pressure or vacuum, structure 100 is flexible enough to bend in this manner. After application of pressure or vacuum while bent around the cylinder, structure 100 is rigidified into its assumed shape, as shown by the reconfigured shape in Figure 3B. Figure 3B also shows that the rigidified structure 100 is strong enough to withstand the weight of the cylinder.

[0036]

[0051] Referring to Figure 4A, the reconfigurable structure 100 is shown wrapped or wrapped around the end of a rod 402. In the absence of application of pressure or vacuum, the structure 100 is flexible enough to bend in this manner. After application of pressure or vacuum while bent around the rod, the structure 100 is rigidified into its assumed shape, as shown by the reconfigured shape in Figure 4B. Figure 4C also shows that the rigidified structure 100 is strong enough to withstand the weight of a cylinder 202.

[0037]

[0052] Ceasing the application of pressure (eg, turning off the vacuum and / or exhaust to atmosphere) will cause the stiffened structure to return or move towards its flexible configuration.

[0038]

[0053] FIG. 5A shows an example of a cross-sectional schematic of a reconfigurable structure 100. In this example (not to scale), the structure 100 comprises a sealed containment area 204. The sealed containment area 204 seals a single core 206 flanked at its upper and lower surfaces by inner fibrous shear stabilization layers 212, 212' adjacent to outer sheet layers 208, 208'. The containment area may be sealed by, for example, an elastomeric or plastic material 203 and may be referred to as an outer sealed vessel. A vacuum / pressure line 210 is fluidly connected to the sealed area 204. The vacuum pressure line may be supported to prevent collapse when suction is applied. In some examples, suction (negative pressure) is applied from the end of the device as shown. Alternatively or additionally, such may be distributed within the structure, applied in two or more locations, and / or in a central location.

[0039]

[0054] Figure 5B shows a schematic of the device of claim 5A in a rigidified configuration with negative pressure (vacuum) applied. In this example, the negative pressure presses and laminates the outer sheets 208, 208' against the inner fiber shear stabilizing sheets 212, 212' and the core layer 206. The core may be relatively incompressible in this axis. The spacing between layers in Figure 5A is exaggerated because the layers (including the outer sealed chamber) may flatten and rest on top of each other, albeit loosely, when in the non-rigidified configuration.

[0040]

[0055] 5C shows another schematic cross-sectional view of another example reconfigurable structure 100' that includes a containment region 204 that is containment of a single core 206 flanked on both sides by internal fibrous shear stabilization layers 212, 212' adjacent to the outer facesheet layers 208, 208' at the upper and lower surfaces. In this example, third and fourth shear stabilization layers 212'', 212''' are also included on the outside of the outer facesheet layers. In any of the described devices, additional shear stabilization layers 212'', 212''' can be present on both sides of the face sheets 208, 208'. This can provide the face sheets with increased shearability and thereby increased stiffening.

[0041]

[0056] In any of the devices described herein, the shear stabilizing layer 212, 212' may be bonded to the core 206 (or each core). This may provide additional shear reinforcement with respect to the face sheets. It may be more firmly attached and provide increased rigidity, while still allowing the core to be flexible, since the shear stabilizing layer may be elastomeric.

[0042]

[0057] Any of the devices described herein may include a breathable material (e.g., between the interior of the outer sealed container, e.g., the bag 203, and an outer layer of the composite stack of layers, e.g., the outer sheet 208 or the outer sheath layer 212''), such as a fabric or a "breather" made of randomly oriented fibers, which may enhance the release of air from the device.

[0043]

[0058] As stated, the core layer may provide a well-defined thickness or cross-sectional height to the reconfigurable structure while also providing flexibility. In some embodiments, the core layer comprises a material that is discontinuous along its surface. Discontinuous may refer to a material that is provided with indentations along its surface. Discontinuous may also refer to a material that is at least partially configured as a mesh, web, or net or that otherwise includes connected strands of material (e.g., honeycomb).

[0044]

[0059] In some embodiments, the core layer has a contact area percentage of about 5-100%, 10-100%, 15-100%, 20-100%, 25-100%, 30-100%, 35-100%, 40-100%, 45-100%, 50-100%, 55-100%, 60-100%, 65-100%, 70-100%, 75-100%, 80-100%, 85-100%, 90-100%, 10-90%, 20-80%, 30-70%, 40-60%, 45-55%, etc. In some examples, the contact area of ​​the core may be low (e.g., less than 15%, less than 10%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, etc.).

[0045]

[0060] In some embodiments, each core layer has a thickness of about .1-10 cm, .5-10 cm, .1-5 cm, .5-5 cm, .5-2 cm, 1-5 cm, 1-10 cm, 2-10 cm, 2-8 cm, 2-5 cm, 3-10 cm, 3-8 cm, 3-5 cm, 4-10 cm, 4-8 cm, 4-5 cm, 5-10 cm, etc. Multiple core layers may be used and may be separated by shear stabilizing layers. The total core thickness may be large. For example, the total core (or core region) may have a thickness of between 0.1 cm and 50 cm (e.g., between 0.1 cm and 40 cm, between 1 cm and 35 cm, between 1 cm and 31 cm, between 1 cm and 25 cm, between 1 cm and 16 cm, etc.).

[0046]

[0061] For example, Figure 6A shows an example of a device 100'' that includes a pair of shear stabilizing layers 212, 212' and a core 206' with facing sheets 208, 208' on either side, similar to that shown in Figure 5A. In this example, the core 206 has a height 228' that is greater than the core height 228 of Figures 5A and 5B. The greater height can provide greater stiffness when negative pressure is applied.

[0047]

[0062] FIG. 6B shows another example of a schematic of a rigidifiable shell structure 100''' described herein. In FIG. 6B, the core includes multiple core layers 206'', 206''', 206'''', each separated by a shear stabilizing layer 212'', 212'''. The total core thickness of the example shown in FIG. 6B is similar to that shown in FIG. 6A, and the final stiffness under similar negative pressure is roughly comparable. However, the base flexibility of the device of FIG. 6B with multiple core layers can be significantly higher.

[0048]

[0063] In some embodiments, the core layer has a viscosity of about 0.0160 to 0.4805 g / cm 3 (Approx. 1 to 30 lb / ft 3 ) (for example, 0.0320 to 0.3203 g / cm 3 (2-20lb / ft 3 ), 0.0320~0.2883g / cm 3 (2~18lb / ft 3), 0.0320~0.2403g / cm 3 (2-15lb / ft 3 ) or the like. Generally, the core is configured to be bending flexible, yet incompressible, and to provide a defined height through which shear loads are transferred. The core layer can comprise one or more of a variety of materials. In some embodiments, the core layer comprises Nomex or aluminum (e.g., Nomex or aluminum honeycomb as shown in FIG. 8A). As mentioned, in some embodiments, the core layer comprises foam. The foam can comprise a sheet that can be at least partially scored or that is not scored. In some scored embodiments, the foam comprises the back support matrix. In some embodiments, the core layer comprises balsa wood. The balsa wood can comprise a sheet that can be at least partially scored (FIG. 8B) or that is not scored. In some scored embodiments, the balsa wood comprises the back support matrix.

[0049]

[0064] As mentioned above, the face sheet may comprise a material that can shift relative to adjacent components, allowing the structure to be deformable. For example, the face sheet may comprise a fiber fabric. The fabric may be woven (see, e.g., FIG. 7B) or braided (e.g., the braided plastic shown in FIG. 7A). The fabric may comprise multiple layers of unidirectional fibers intermittently attached to one another. The fibers in the fabric may comprise high strength, high axial stiffness fibers (e.g., carbon, Kevlar™, Technora™, fiberglass, Dyneema™, Vectran™, etc.).

[0050]

[0065] In some embodiments, the face sheet fabric can have a fiber weave or braid angle relative to the longitudinal axis of the structure of about 0-90°, 10-90°, 20-90°, 30-90°, 40-90°, 50-90°, 60-90°, 70-90°, 80-90°, 20-80°, 30-70°, 40-60°, 30-50°, 40-50°, etc.

[0051]

[0066] In some embodiments, the facing sheet has a thickness of about .1-5 cm, .5-5 cm, .5-2 cm, 1-5 cm, 2-5 cm, 3-5 cm, 4-5 cm, etc.

[0052]

[0067] In some embodiments, the face sheet has a coverage of 30% to 70%, such as 40% to 60%, e.g., 30%, 40%, 50%, 60% or 70%, where the coverage is the percentage of the underlying surface that is covered or obstructed by the fabric fibers.

[0053]

[0068] In some embodiments, the face sheets include tensile elements having a modulus of elasticity of about 1-400 GPA, 10-200 GPa, 50-200 GPa, 50-100 GPa, 60-100 GPa, 70-100 GPa, greater than 100 GPa, greater than 200 GPa, etc. Generally, the tensile strength and stiffness of the fibers are relatively high, but the fibers or filaments may slip or move relative to one another.

[0054]

[0069] In some embodiments, the face sheet comprises a lightweight material having a low density. The density is about 1 g / cm 3 Less than 0.1-3g / cm 3 , 0.1~2g / cm 3 , 0.1~4g / cm 3 , 0.1~5g / cm 3 , 0.1~6g / cm 3 , 0.1~7g / cm 3 , 0.1~8g / cm 3 , 0.1~9g / cm 3 , 0.

[0055]

[0070] 1~10g / cm3 The fibers may have long edges of 0.00254 cm to 0.1524 cm (0.001 inch to 0.060 inch), such as 0.0127 cm (0.005 inch), 0.1778 cm (0.007 inch), 0.010 inch, or 0.012 inch, and narrow edges of 0.00254 cm (0.001 inch), 0.00508 cm (0.002 inch), or narrow edges of 0.00762 cm (0.005 inch), 0.007 inch, 0.010 inch, or 0.012 inch. The fibers can be rectangular / flat (e.g., with a short edge of 0.0003 inches to 0.030 inches, such as 0.003 inches), round (e.g., with a diameter of 0.001 inches to 0.020 inches, such as 0.005 inches, 0.01 inches, or 0.012 inches), or oval. In some embodiments, some fibers can be flat and some fibers can be round.

[0056]

[0071] In some embodiments, the fibers can be made of metal filaments (e.g., stainless steel, aluminum, nitinol, tungsten, or titanium), plastics (nylon, polyester terephthalate, PEEK, polyetherimide), or high strength, high axial stiffness fibers (e.g., carbon, Kevlar™, Technora™, aramid, fiberglass, Dyneema™ or UHMWPE, or liquid crystal polymers such as Vectran™). In some embodiments, the fibers can be made of multi-layer composites, such as a metal core with a thin elastomeric coating.

[0057]

[0072] The face sheet may be composed of monofilaments or small fiber bundles with up to 1000 fibers per bundle. Advantageously, a higher number of strands may help stiffen the face sheet through enhanced fiber-to-fiber interaction.

[0058]

[0073] The core and the face sheets are held within the sealed region. The sealed region can comprise a flexible material that is fluid impermeable. The sealed region can be configured to move radially inward when a vacuum is applied and be pulled down against and conform to the surface of the inner layer. The sealed region boundary layer can be soft, atraumatic, and can be sealed at both ends to create a vacuum-tight chamber. The sealed region boundary layer can comprise plastic. The sealed region boundary layer can be elastic, for example made from urethane.

[0059]

[0074] In some embodiments, the entire structure comprises a sealed region, hi some embodiments, the sealed region makes up only one or more portions of the structure.

[0060]

[0075] The hardness of the boundary layer of the sealed area can be, for example, 30A-80A, 40-70A, 50-60D, and the like.

[0061]

[0076] The boundary layer thickness of the sealed area can be about 0.0001 to 1 inch, 0.001 to 1 inch, 0.005 to 1 inch, 0.01 to 1 inch, 0.05 to 1 inch, 0.01 to 1 inch, 0.05 to 1 inch, 0.01 to 0.5 inch, or 0.5 to 1 inch thick.

[0062]

[0077] In some embodiments, the boundary layer of the sealed region can be a plastic, including, for example, polyester, nylon, or PEEK.

[0063]

[0078] Vacuum / pressure line 210 is fluidly connected to sealed region 204. Vacuum / pressure line 210 may comprise tubing (e.g., plastic or elastomeric tubing). In some embodiments, line 210 is configured to apply between a minimum and maximum atmosphere of vacuum (e.g., approximately 14.7 psi).

[0064]

[0079] The face sheets are selectively adhered or attached to the core through the application of pressure (e.g., negative pressure). This selective attachment / detachment of the face sheets to the core allows the structure to switch between rigid and flexible configurations.

[0065]

[0080] The stiffness of the structure can be varied by adjusting the core (e.g., core thickness, wrapability, contact area percentage, etc.). Stiffness can also be adjusted by adjusting the face sheets (e.g., material, angle, thickness, open area, modulus, fiber diameter, weave, etc.). Stiffness can also be adjusted by adjusting the properties of the sealed regions (e.g., modulus, durometer, thickness, etc.). Stiffness of the structure can be varied by adjusting pressure or vacuum levels.

[0066]

[0081] One exemplary method of use includes setting the reconfigurable structure to a position or shape. A vacuum can then be applied to the system. As the face sheets are sucked against the core, they provide inner fiber shear stabilization of the face sheets while pressure fixing the face sheets to the core. When pressure is released, the face sheets are no longer sucked against the core and the fibers are free to slip relative to each other, allowing the system to return to its flexible configuration.

[0067]

[0082] The structures disclosed herein are advantageous in that they can be packed into a first state (e.g., flat or rolled) and then rapidly transitioned into a load-bearing structure that can assume a wide variety of shapes.

[0068]

[0083] The structures described herein can be any number of shapes (e.g., square, round, oval, rectangular, etc.). The structures can be used as medical devices. For example, they can be used for elements that need to enter the body through a small hole and then expand inside the body to become a larger plate or structure that can be used to push, move, or reposition anatomical structures. As another example, the structures can be used for exoskeletons or casts.

[0069]

[0084] The structures described herein can also be used in non-medical applications, for example, the structures can be used for housing, buildings, or evacuation shelters that can be easily compacted and quickly assembled.

[0070]

[0085] It should be appreciated that all combinations of the above-mentioned concepts, and the additional concepts described in more detail below (unless those concepts are mutually inconsistent), are contemplated as being part of the inventive subject matter disclosed herein and may be used to achieve the benefits described herein.

[0071]

[0086] The process parameters and order of steps described and / or illustrated herein are given by way of example only and can be varied as desired. For example, although the steps illustrated and / or illustrated herein may be illustrated or described in a particular order, the steps do not necessarily have to be performed in the order illustrated or illustrated. The various exemplary methods described and / or illustrated herein may also omit one or more of the steps described or illustrated herein or include additional steps in addition to those disclosed.

[0072]

[0087] When a feature or element is referred to herein as being "on" another feature or element, it may be directly on the other feature or element, or there may be intervening features and / or elements present. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements present. It will also be understood that when a feature or element is referred to as being "connected," "attached," or "coupled" to another feature or element, it may be directly connected, attached, or coupled to the other feature or element, or there may be intervening features or elements present. In contrast, when a feature or element is referred to as being "directly connected," "directly attached," or "directly coupled" to another feature or element, there are no intervening features or elements present. Although described or illustrated with respect to one embodiment, the features and elements so described or illustrated may also apply to other embodiments. Those skilled in the art will also recognize that references to structures or features disposed "adjacent" to another feature may have portions that are on or below the adjacent feature.

[0073]

[0088] The terminology used herein is merely for the purpose of describing particular embodiments and is not intended to limit the present invention. For example, as used herein, the singular forms "a," "an," and "the" are intended to include the plural unless the context clearly dictates otherwise. Furthermore, it will be understood that the terms "comprising" and / or "comprising" as used herein specify the presence of the stated features, steps, operations, elements, and / or components, but do not preclude the presence and addition of one or more other features, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any combination of one or more of the associated listed items and may be abbreviated as " / ."

[0074]

[0089] Spatially relative terms such as "below", "under", "lower", "above", "upper" and the like are used herein for convenience of description to describe the relationship of an element or feature shown in a figure to another element or feature. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as being "below" or "below" another element or feature will be oriented "above" that other element or feature. Thus, the exemplary term "below" can encompass both an orientation above and below. The device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein will be interpreted accordingly. Similarly, the terms "upward", "downward", "vertical", "horizontal", and the like are used herein for descriptive purposes only, unless otherwise noted.

[0075]

[0090] Although the terms "first" and "second" may be used herein to describe various features / elements (including steps), those features / elements should not be limited by those terms unless the context clearly dictates otherwise. These terms may be used to distinguish one feature / element from another. Thus, a first feature / element discussed below may be referred to as a second feature / element, and similarly, a second feature / element discussed below may be referred to as a first feature / element, without departing from the teachings of the present invention.

[0076]

[0091] Throughout this specification and the claims that follow, unless the context requires otherwise, the word "comprising" and variations such as "comprising" and "comprising" mean that various components can be used jointly in methods and articles (e.g., compositions and apparatuses, including devices and methods). For example, the term "comprising" shall be understood to imply the inclusion of any stated elements or steps, but not the exclusion of other elements or steps.

[0077]

[0092] In general, any apparatus and methods described herein should be understood to be inclusive, although all or a subset of the components and / or steps may alternatively be exclusive, and various components, steps, subcomponents, or substeps may be expressed as "consisting of" or alternatively "consisting essentially of."

[0078]

[0093] As used herein and in the claims, including as used in the examples and unless otherwise noted, all numbers may be read as preceded by the word "about" or "approximately" even if the word does not explicitly appear. The expressions "about" or "approximately" may be used in describing a size and / or location to mean that the stated value and / or location is within a reasonable expected range of values ​​and / or locations. For example, a numerical value may have a value that is + / -0.1% of the stated value (or range of values), + / -1% of the stated value (or range of values), + / -2% of the stated value (or range of values), + / -5% of the stated value (or range of values), + / -10% of the stated value (or range of values), etc. Also, a numerical value given herein should be understood to include about or approximately that value unless the context dictates otherwise. For example, if the value "10" is disclosed, then "about 10" is also disclosed. Any numerical ranges stated herein are intended to include all subranges subsumed therein. It is also understood that when a value is disclosed as being "less than or equal to" a certain value, "greater than or equal to" and possible ranges between the values ​​are also disclosed, as would be properly understood by one of ordinary skill in the art. For example, if a value "X" is disclosed, "less than or equal to X" as well as "greater than or equal to X" (e.g., where X is a number) are also disclosed. It is also understood that throughout this application, data is provided in several different formats, and that this data represents endpoints and starting points, as well as ranges for any combination of the data points. For example, if a specific data point "10" and a specific data point "15" are disclosed, it is understood that greater than, greater than, less than, less than, and equal to 10 and 15, as well as between 10 and 15, are considered to be disclosed. It is also understood that each unit between two particular units is also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0079]

[0094] Although various exemplary embodiments have been described above, any of a number of modifications may be made to the various embodiments without departing from the scope of the invention as set forth in the claims. For example, the order in which various described method steps are performed may often be changed in alternative embodiments, and in other alternative embodiments, one or more methods may be omitted altogether. Optional features of various device and system embodiments may be included in some embodiments and not included in other embodiments. Thus, the above description has been provided primarily for illustrative purposes and should not be construed as limiting the scope of the invention, as the scope of the invention is set forth in the claims.

[0080]

[0095] The examples and illustrations contained herein show, by way of illustration and not limitation, specific embodiments in which the subject matter may be practiced. As stated, other embodiments may be utilized and derived therefrom, and structural and logical substitutions and changes may be made without departing from the scope of the present disclosure. Such embodiments of the inventive subject matter may be referred to herein, individually or collectively, by the term "invention" for mere convenience and without any intention of spontaneously limiting the scope of the present application to any single invention or inventive concept when in fact more than one is disclosed. Thus, although specific embodiments have been illustrated and described herein, any configuration that is expected to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover all modifications and variations of the various embodiments. Combinations of the above and other embodiments not specifically described herein will be apparent to those skilled in the art upon consideration of the above description.

Claims

1. A flexible core layer; a first face sheet disposed on a first side of the flexible core layer; a second face sheet disposed on a second side of the flexible core layer opposite from the first side of the flexible core layer; an outer layer surrounding and forming a seal around the flexible core layer, the first face sheet, and the second face sheet; an inlet disposed within the outer layer and configured to permit application of pressure therethrough; Equipped with A rigidizable shell structure, wherein the first and second face sheets are configured to shift relative to the flexible core layer in a first configuration in which they are flexible without the application of pressure from the inlet, and the first and second face sheets are pressure-fixed to the flexible core layer in a second configuration in which they are rigid under the application of pressure from the inlet.

2. The structure of claim 1 , wherein the pressure is a negative pressure.

3. The structure of claim 1 , wherein the flexible core layer comprises Nomex™ or aluminum honeycomb.

4. The structure of claim 1 , wherein a shear enhancing layer is utilized.

5. The structure of claim 1 wherein multiple core layers are utilized.

6. The structure of claim 1 , wherein the flexible core layer comprises foam.

7. The structure of claim 1 , wherein the flexible core layer comprises scored balsa wood.

8. The structure of claim 1 , wherein the flexible core layer is discontinuous.

9. 10. The structure of claim 1, wherein the flexible core layer comprises a thickness of about .1-10 cm, .5-10 cm, .1-5 cm, .5-5 cm, .5-2 cm, 1-5 cm, 1-10 cm, 2-10 cm, 2-8 cm, 2-5 cm, 3-10 cm, 3-8 cm, 3-5 cm, 4-10 cm, 4-8 cm, 4-5 cm, or 5-10 cm.

10. The structure of claim 1 , wherein the first face sheet comprises a fibrous fabric.

11. The structure of claim 10 , wherein the fabric is woven or braided.

12. 10. The structure of claim 1, wherein the first face sheet and the second face sheet comprise a thickness of about 0.1 to 5 cm, 0.5 to 5 cm, or 0.5 to 2 cm.

13. The structure of claim 1 , wherein the face sheet comprises a coverage of about 30% to 70%, such as 40% to 60%, for example 30%, 40%, 50%, 60% or 70%.

14. The first face sheet and the second face sheet have a density of about 1 to 3 g / cm ３ , 1 to 2 g / cm ３ , 1 to 4 g / cm ３ , 1 to 5 g / cm ３ , 1 to 6 g / cm ３ , 1 to 7 g / cm ３ , 1 to 8 g / cm ３ , 1 to 9 g / cm ３ , or 1 to 10 g / cm ３ The structure of claim 1 comprising a density of

15. The structure of claim 1 , wherein the first face sheet and the second face sheet comprise fibers that are rectangular, flat, round, and / or oval.

16. The structure of claim 1 , wherein the first face sheet and the second face sheet comprise fibers that are plastic or metal.

17. The structure of claim 1 , wherein the outer layer comprises an elastomer.

18. The structure of claim 1 , wherein the outer layer comprises plastic.

19. 10. The structure of claim 1, wherein the outer layer comprises a hardness of about 30A to 80A or about 50 to 60D.

20. 10. The structure of claim 1, wherein the outer layer comprises a thickness of about 0.0001 to 1 inch, 0.001 to 1 inch, 0.005 to 1 inch, 0.01 to 1 inch, 0.05 to 1 inch, 0.01 to 1 inch, 0.05 to 1 inch, 0.01 to 0.5 inch, or 0.5 to 1 inch.

21. The structure of claim 1 , wherein the inlet is attached to a tube.

22. A flexible core layer; a first sheet disposed on a first side of the flexible core layer; a second sheet disposed on a second side of the flexible core layer opposite from the first side of the flexible core layer; an outer layer surrounding and forming a seal around the flexible core layer, the first sheet, and the second sheet; an inlet disposed within the outer layer and configured to permit application of pressure therethrough; Equipped with A rigidizable shell structure, wherein the first sheet and the second sheet are shifted relative to the flexible core layer in a first configuration in which they are flexible without the application of pressure through the inlet, and are rigidly secured to the flexible core layer in a second configuration in which the first sheet and the second sheet are rigid under the application of pressure through the inlet.

23. 1. A method of transitioning a shell structure from a flexible configuration to a rigid configuration, comprising: setting a shell structure into a shape or position, the shell structure including a sealed outer layer surrounding a core layer disposed between a first face sheet and a second face sheet, the first face sheet and the second face sheet configured to be displaced relative to the core layer; applying pressure to the shell structure through the inlets in the sealed outer layer, thereby press-fitting the first and second face sheets to the core layer and rigidifying the shell structure in the shape or position; The method includes:

24. 24. The method of claim 23, wherein applying pressure to the shell structure comprises applying a negative pressure to the shell structure.

25. 24. The method of claim 23, wherein applying pressure to the shell structure comprises applying a negative pressure of between 0.01 and 14.7 psi to the shell structure.

26. 24. The method of claim 23, further comprising the step of removing the applied pressure, thereby allowing the shell structure to transition back to the flexible configuration.

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