A need exists for inexpensive protective cladding with superior resistance to wind damage, including penetration of debris generated by natural forces, such as tornadoes and hurricanes. Coating or covering the inexpensive core of a structure, such as a wall, with a pliable material of a tailored “toughness” reduces or completely eliminates the generation of structural debris and through penetration of fragments and debris from an event such as a hurricane, tornado, or even a nearby explosion such as may occur with a natural gas line rupture.
Select embodiments of the present invention also have excellent energy absorbing capacity against blast forces. This capacity is often described as toughness. Select embodiments of the present invention obtain their toughness qualities through engineering of the type and quantity of component materials as well as engineering the geometry of components as applied in specific applications.
Further, because select embodiments of the present invention provide a tailored toughness, they are suitable for employment with structural members, such as sheetrock-based walls, that may be used in residential housing as well as employment in commercial structures such as banks or security vaults. Structural members thus modified protect against natural forces, specifically dynamic loading and debris impact from nearby blasts, tornados and hurricanes.
In select embodiments of the present invention, a prophylactic system, tailored to meet a user's requirements, reduces or eliminates damage to the inside of a structure having exterior sides which upon impact by an external force would otherwise generate flying debris inside the structure. The prophylactic system comprises an elastic membrane (elastomeric configuration) having a length, a width, and a thickness, the thickness much less than either of the length or width; reinforcement incorporated in the membrane comprised of bundles of fibers aligned in a scrim comprising warp fiber bundles and weft fiber bundles arranged so that fiber bundles are non-parallel to each of the longitudinal axis defining the length and the horizontal axis defining the width of the membrane and the fiber bundles are aligned to create spacing between each fiber bundle and an adjacent parallel fiber bundle; and an adhesive applied to affix the reinforced membrane to the inside of the exterior sides.
In select embodiments of the present invention, the membrane is a polymer or copolymer in which the reinforcement is embedded at the place of manufacturing of the membrane. In select embodiments of the present invention, the membrane is provided in a thickness between about 10 mil to about 0.5 in. (12.7 mm), preferably in a thickness between about 50 and about 100 mil.
In select embodiments of the present invention the membrane is capable of elongation from about 100% to about 500%.
In select embodiments of the present invention one or more types of the fibers comprise one or more types of polymer or copolymer, the fibers incorporated in the fiber bundles to comprise the warp and weft of the scrim, the fiber bundles having a length, a width much less than the length and a thickness much less than the width, and the fiber bundles aligned so that the spacing is defined by a pre-specified clear space ratio (CSR) defined as the area of the scrim covered by the fiber bundles divided by the area of the scrim that is not covered by the fiber bundles.
In select embodiments of the present invention, CSR is specified to be between about 0.25 and about 4.0.
In select embodiments of the present invention the types of fibers are selected from: polyester, aramid, para-aramid, aromatic polyamide, poly(p-phenylene-2,6-benzobiosoxazole), fiberglass, carbon fiber, polypropylene, nylon, aliphatic polymer, ultra-high molecular weight polyethylene (UHMWPE), high modulus polyethylene (HMPE), geo-grid material, bi-axial geo-grid material, geo-fabric material, bi-axial geo-fabric material, metallic grids, metallic meshes, metallic membranes, and combinations thereof.
In select embodiments of the present invention the configuration of the fiber bundles may be: woven, braided, stitched, mesh fabric, and combinations thereof.
In select embodiments of the present invention, the warp fiber bundles of the reinforcing scrim are fixed at between about 30 and about 60 degrees with respect to the longitudinal axis of the membrane and the weft fiber bundles of the reinforcing scrim are fixed about perpendicular to the warp fiber bundles.
In select embodiments of the present invention the warp fiber bundles of the reinforcing scrim are fixed at between about 30 and about 60 degrees with respect to the longitudinal axis of the membrane and the weft fiber bundles of the reinforcing scrim are fixed non-perpendicular to the warp fiber bundles.
In select embodiments of the present invention the warp fiber bundles of the reinforcing scrim are fixed at about 45 degrees with respect to the longitudinal axis of the membrane and the weft fiber bundles of the reinforcing scrim are fixed about perpendicular to the warp fiber bundles.
In select embodiments of the present invention the warp fiber bundles of the reinforcing scrim are fixed at about 45 degrees with respect to the longitudinal axis of the membrane and the weft fiber bundles of the reinforcing scrim are fixed non-perpendicular to the warp fiber bundles.
In select embodiments of the present invention the reinforced membrane is extended to be affixed to one or more portions of the structure that abut one or more sides of the structure.
In select embodiments of the present invention the reinforced membrane is extended to be affixed to both the ceiling and the floor abutting exterior walls of a structure.
In select embodiments of the present invention the adhesive is applied to sides of the structure, such as exterior walls, prior to affixing the reinforced membrane to the sides.
In select embodiments of the present invention adhesive is applied to both the membrane and the sides of the structure prior to affixing the reinforced membrane to the sides.
In select embodiments of the present invention the adhesive is applied to the reinforced membrane prior to affixing the reinforced membrane to the sides of the structure.
In select embodiments of the present invention the adhesive is applied to the reinforced membrane at the place of manufacture of the reinforced membrane and the applied adhesive protected with a peelable sheet that is removed just prior to installing the reinforced membrane.
In select embodiments of the present invention the adhesive is of a type that may be used with no need for safety gear specific to use of the adhesive.
In select embodiments of the present invention the components of the adhesive may comprise: rubber, acrylic, epoxy, urethane, polyurea and combinations thereof.
In select embodiments of the present invention the adhesive has a minimum bond strength of at least 40 oz./in. to maintain a cohesive bond to the structural element.
In select embodiments of the present invention the adhesive is applied at a thickness from about 2 mil to about 50 mil.
In select embodiments of the present invention a structure having at least exterior walls incorporates a prophylactic system, tailored to meet a user's requirements, for significantly reducing or eliminating hazards to occupants and damage to the inside of the structure in which the exterior walls are impacted by an external force that otherwise would generate flying debris inside the structure. The prophylactic system comprises: an elastic membrane (elastomeric configuration) having a length, a width, and a thickness, the thickness much less than either of the length or width; reinforcement incorporated in the membrane comprised of bundles of fibers aligned in a scrim comprising warp fiber bundles and weft fiber bundles arranged so that the fiber bundles are non-parallel to each of the longitudinal axis defining the length and the horizontal axis defining the width of the membrane and the fiber bundles are aligned to create spacing between each fiber bundle and an adjacent parallel fiber bundle; and an adhesive applied to affix the reinforced membrane to the inside of the exterior walls.
In select embodiments of the present invention a prophylactic system, tailored to meet a user's requirements, significantly reduces or eliminates hazards and damage to items outside a structure, the interior of the sides (such as exterior walls) of which are impacted by an internal force that otherwise would generate flying debris outside the structure. The prophylactic system comprises: a membrane (an elastomeric configuration) having a length, a width, and a thickness, the thickness much less than either of the length or the width, the membrane incorporating reinforcement comprising bundles of fibers aligned in a scrim, the fiber bundles non-parallel to each of the axes defining the length and width of the membrane and the fiber bundles aligned to create spacing between each fiber bundle and a parallel fiber bundle; and an adhesive applied to affix the reinforced membrane to the outside of the sides of the structure.
In select embodiments of the present invention, a prophylactic system for reducing or eliminating damage to the inside of a structure having sides which upon impact by an external force would otherwise generate flying debris inside the structure, comprises: an elastomeric configuration of a toughness tailored to a user's requirements having a length, a width, and a thickness, the thickness much less than either of the length or width, the elastomeric configuration incorporating reinforcement comprising bundles of fibers aligned in a scrim comprising warp fiber bundles and weft fiber bundles, the fiber bundles approximately parallel to each of the axes defining the length and width of the elastomeric configuration, such that the fiber bundles are aligned to create spacing between each fiber bundle and a next fiber bundle parallel thereto, and wherein the prophylactic system is aligned on a bias with respect to either of the axes defining the length and width and adhesive applied to affix the reinforced elastomeric configuration to the inside of a side of the structure.
A prophylactic system for significantly reducing or eliminating damage to items outside a structure should the interior sides of exterior walls be impacted by an internal force that otherwise would generate flying debris outside the structure, comprising: an elastomeric configuration of a toughness tailored to a user's requirements having a length, a width, and a thickness, the thickness much less than either of the length or the width, the elastomeric configuration incorporating reinforcement comprising bundles of fibers, aligned in a scrim parallel to the axes defining the length and width of the reinforced elastomeric configuration such that the fiber bundles are aligned to create spacing between each fiber bundle and an adjacent parallel bundle, and such that the prophylactic system is aligned on a bias with respect to either of the axes defining the length and width of the reinforced elastomeric configuration; and adhesive applied to affix the reinforced elastomeric configuration to the outside of the exterior walls of the structure.
In select embodiments of the present invention the principal component of the elastomeric configuration is a membrane 101 or substrate comprising at least one material provided in at least one layer. Polymer or copolymer materials comprising a membrane 101 of select embodiments of the present invention may be selected from any of the following: elastomeric polymers, polyurethane, polyurea, polyethylene, polypropylene, polyolefin, silicone, polychloroprene (e.g., Neoprene), polyisoprene (e.g., natural rubber), isobutylene isoprene (e.g., butyl), polyvinylalcohol (PVA), polyvinylbutryl (PBA), polymer ionomer resins (e.g., SURLYN®), modified polyolefin, halogenated polyolefin, polyester, urethane, rubber (e.g., EPDM, Nitrile), hydrocarbons (e.g., ethylene-propylene terpolymer), chlorosulfonated polyethylene, styrene butadiene, polysulfide, acrylonitrile butadiene, fluoroelastomer, epichloronydrin, combinations thereof, and like materials with similar characteristics.
In select embodiments of the present invention a reinforced membrane 100 exhibits a strength of between about 100 to about 800 pounds per linear inch (pli). In select embodiments of the present invention the membrane itself 101 is provided in a thickness between about 10 mil to about 0.5 in. (12.7 mm), preferably between about 50 and about 100 mil. In select embodiments of the present invention the membrane 101 is capable of elongation from about 100% to about 500%.
In select embodiments of the present invention reinforcement is provided as a scrim of elastic fiber “bundles” (hereafter simply termed fibers) 102, 103. Each bundle 102, 103 comprises one or more “ends” or “yarns” (of fibers) as necessary to meet a pre-specified strength. The fibers 102, 103 are of a pre-specified tensile strength and are woven in a loose weave to form a scrim. The warp fibers 103 interleave with the weft fibers 102 to produce a scrim resulting in a matrix of spaces 106 between the weft 102 and warp 103 fibers as shown in
In select embodiments of the present invention, the fibers 102, 103 have a tensile strength of about 100 to 800 pli with a fiber denier of at least 10, an individual fiber breaking strength of at least 5 grams per denier, and the greatest dimension perpendicular to the longitudinal axis of the fiber (bundles) 102, 103 is at least 0.005 in. (0.13 mm). This “greatest dimension” could be a diameter for a cylindrical “bundle” or a width for a flat bundle having a length, width and depth (thickness).
In select embodiments of the present invention, the fibers 102, 103 may be selected from any of the following: polyester, aramid (e.g., KEVLAR®), para-aramid, poly(p-phenylene-2,6-benzobiosoxazole)(ZYLON®), fiberglass, carbon fiber, polypropylene, nylon, aliphatic polymer (e.g., SPECTRA®, DYNEEMA®), ultra-high molecular weight polyethylene (UHMWPE) (or high modulus polyethylene (HMPE), geo-grid material, bi-axial geo-grid material, geo-fabric material, bi-axial geo-fabric material, metallic grids, metallic meshes, metallic membranes, and combinations thereof Refer to
In select embodiments of the present invention the type and geometry of the scrim to be used as reinforcement is specified. For example, refer to
Refer to
In select embodiments of the present invention, the adhesive for bonding the reinforced elastomeric material to a structure is preferably a “pressure sensitive” adhesive, i.e., the elastomeric material is bonded to the structure by applying pressure to the elastomeric material once it is “fitted” to the structure. Pressure sensitive adhesives used in select embodiments of the present invention may be selected from those comprising at least in part any of: rubber, acrylic, epoxy, urethane, polyurea and combinations of the above. The minimum bond strength of adhesives used in select embodiments of the present invention referencing Pressure Sensitive Tape Council (PSTC) Standards 3 and 6 or ASTM D-3330 is at least 40 oz./in. to maintain a cohesive bond to the structural element. For select embodiments of the present invention, the adhesive thickness is from about 2 mil to about 50 mil.
An example specification for a reinforced elastomeric configuration useful in select embodiments of the present invention may be:
a thermoplastic membrane
a flat fiber bundle comprising aramid fibers
an acrylic adhesive
Tests were conducted for selected embodiments of the invention. Refer to
Curve 401 shows the performance of the control wall. As may be expected, the control wall failed (at point 404) at a lower pressure (1.84 psi) and greater deflection (0.82 in.) than either of the other two. Also, the elastomeric material stretched to failure at a much lower pressure (2.51 psi) and higher deflection (4.63 in.) than either of the reinforced configurations. Referring to curve 402, it is evident that the elastomeric material with the 0/90° orientation of the aramid fibers is stiffer throughout the test and slightly stronger initially than that of the 45/−45° orientation. The 0/90° configuration of the aramid fibers sustains a pressure of 2.54 psi with a deflection of only 0.38 in. at the point of failure of the wall as shown at 404 on curve 402. The elastomeric material itself fails at 4.22 psi at a deflection of 3.36 in., again indicating its “stiffness” as compared to either of the other two configurations. Referring to curve 403, it is evident that the reinforced elastomeric material “gives” more both at the initial failure point 404 of the wall (2.5 psi at 0.63 in. deflection) and at failure of the elastomeric material configuration itself (4.94 psi at 4.65 in. deflection). This additional yielding enables the 45/−45° configuration to prolong the period over which any external impact occurs, resulting in improved resistance to a: wall fracture that results in flying debris. Another benefit to the 45/−45° configuration is the additional strength exhibited when, the elastomneric material is stressed along the longitudinal axis of the wall to failure along the horizontal axis of the wall (4.94 psi compared to 4.22 psi for the 0/90° configuration). The physics can be explained by comparing a 0/90° configuration to a 45/−45° configuration as a CMU wall is stressed along a horizontal mortar joint, for example. Both of the fibers in the 45/−45° orientation tend towards realignment in the stiffest orientation, i.e., 90° to the mortar joint. In the 0/90° configuration only the 90° fibers (half of the total) contribute to resisting the load on the wall since the 0° fibers provide no additional strength or ductility with respect to the stress imposed at the horizontal mortar joint.
In addition to hydrostatic tests, “blast” tests were performed for the three configurations described above. All of the sub-scale CMU walls tested in this series had an elastomeric material affixed both to the walls and to the adjacent support structure at both the top and bottom of the sub-scale CMU walls. For the reported results, a fractional “normalized” (relative) value represents both the relative pressure, P, and the relative impulse, I, observed at the test wall for each of these tests, with a relative value of 1.0 being the maximum pressure, P, or impulse, I, observed for all cases. Refer to
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The ability to choose among many polymer or copolymer materials for an appropriate skin material. 102, 103 makes embodiments of the present invention suitable for use in a variety of military, commercial, industrial and consumer applications.
The abstract of the disclosure is provided to comply with the rules requiring an abstract that will allow a searcher to quickly ascertain the subject matter of the technical disclosure of any patent issued from this disclosure. 37 CFR § 1.72(b). Any advantages and benefits described may not apply to all embodiments of the invention.
While the invention has been described in terms of some of its embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims. For example, although the system is described in specific examples for improving the resistance of structural members to impact, blast and fragmentation effects, it may apply to any number of applications including containment facilities in industrial areas or for containment within shipping containers used for transportation of hazardous materials.
In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. Thus, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting, and the invention should be defined only in accordance with the following claims and their equivalents.
Under paragraph 1(a) of Executive Order 10096, the conditions under which this invention was made entitle the Government of the United States, as represented by the Secretary of the Army, to an undivided interest therein on any patent granted thereon by the United States. This and related patents are available for licensing to qualified licensees. Please contact Phillip Stewart at 601 634-4113.