FIELD OF THE INVENTION

A rugged radome closure that is transparent to radio frequency electromagnetic radiation and provides impact and ballistic protected interior space, and a method for manufacturing high contour structures. A further method for mechanically retaining, attaching, and sealing oriented thermoplastic composites.

BACKGROUND OF THE INVENTION

U.S. Patent 5,182,155 relates to a radome structure providing high ballistic protection with low signal loss. The radome has a composite wall structure including alternating layers of polyethylene fiber laminating material which provides high ballistic protection with low signal loss and fiberglass honeycomb core material.

U.S. Patent 7,560,400 relates to a radome comprising flexible composite fabric material including polyester-polyacrylate fibers in a flexible resin matrix material. This reduces radio frequency transmission losses while at the same time providing high strength.

U.S. Patent 7,318,368 relates to an apparatus for broadcasting electromagnetic waves such that electromagnetic receivers are prevented from receiving an intended electromagnetic communication. The device can be portable or stationary and preferably programmable.

U.S. Patent 7,671,801 relates to an electronically scanned ray that includes a plurality of armor segments interspersed between a plurality of transmit/receive integrated microwave modules, and a clamping element compressing the armor segments. Such an armor facilitates a smaller footprint than a radome. U.S. Patent 7,681,485 relates to a laminated, optically transparent, ballistic resistant structure having a first transparent layer, a second transparent layer of ceramic tiles spread across the first layer, and a third transparent layer. The first and third layers are bonded to opposite sides of the second layer by transparent adhesive.

U.S. Patent 7,688,278 relates to a ballistic protective radome consisting of longitudinal layer members densely packed in a uniform array forming a main protective layer. The layer members are electrically isolated such that a continuous gap is fonned in the main protective layer. The layer members are made of mechanical energy absorbing and high tensile strength materials.

The surface of the layer members is electrically conducting.

U.S. Patent 7,870,813 relates to a method for broadcasting electromagnetic waves such that the electromagnetic receivers are prevented from receiving an intended electromagnetic communication.

U.S. Patent 8,054,239 relates to a honeycomb-backed armored radome. The radome is configured to extend over an opening of an antenna and includes a rigid layer underlying a ballistic-resistant layer. ^' Hie rigid layer includes a honeycomb based material having a plurality of holes that extend transversely to the surface of the ballistic resistant layer.

U.S. Patent 8,368,610 relates to a shaped ballistic radome that comprises a system for shielding transmission devices for ballistic deflection and protection of antenna equipment.

U.S. Patent 8,599,095 relates to a broad band ballistic resistant radome. The invention relates to a radome cover for a RF sensor that comprises a first and second ballistic layer each having a ceramic layer. The two ballistic layers are sandwiched between at least two matching layers and the matching layers are impedance matched to the ceramic layers. The radome cover provides ballistic protection for the RF sensor. U.S. Patent 9,385,423 relates to a protective ballistic radome for a satellite antenna which can turn about an axis of rotation and has a circular support in the form of a ring. The walls have their lower ends inserted into an annular groove of the circular support to form a ballistic wall in the form of a tube of a circular section having the same axis of revolution about the satellite antenna.

U.S. Patent 9,669,568 relates to a process for producing a three-dimensionally shaped article comprising: providing a structure containing a plurality of films or tapes of uni- directionally oriented polymer and forming the structure into a three-dimensionally shaped article by applying a force under the melting point of the oriented polymer. Shaped articles thus obtained are suitable for use as anti-ballistic articles.

U.S. Patent publication 2010/0166994 relates to a curved armor product. The armor product is produced by a filament winding process in which a plurality of reinforcing elements in the form of fibers or tapes are impregnated with a polymer matrix and wound onto a mandrel.

The polymer matrix comprises a solution or dispersion of a polymer in a carrier fluid which is partly evaporated during winding. The armor product comprises a high amount of reinforcing elements with respect to the total mass of the product.

U.S. Patent publication 2011/0159233 relates to a process for manufacturing a curved product comprising positioning a plurality of drawn polymeric reinforcing elements onto a mandrel, adhering at least part of the elements to each other, and removing the product from the mandrel. The curved article is preferably an armor article which has good anti-ballistic properties and is substantially free from wrinkles.

U.S. Patent Publication 2014/0000796 relates to a curved armor product produced by a filament winding process in which a plurality of the reinforcing elements are in the form of fibers or tapes that are impregnated with a polymer matrix and wound onto a mandrel. The polymer matrix comprises a solution or dispersion of a polymer in a carrier fluid which is partly evaporated during or after winding. The armor product comprises a high amount of reinforcing elements with respect to the total mass of the product.

U.S. Patent Publication 2014/0078016 relates to a material for radomes. The material comprises at least one laminate component containing polymeric fibers wherein the material has a loss tangent of less than 8 X 10. sup, -3 radians as measured at a frequency chosen from the group of frequencies consisting of 1.8 GHz; 3.9 GHz; 10 GHz; 39.5 GHz; and 72 GHz.

U.S. Patent Publication 2015/0033936 relates to composite panel comprising at least one layer containing at least one tape comprising a thermoplastic polymer selected from the group consisting of polyolefins, polyesters, polyvinyl alcohols, polyacrylonitriles, polyamides or polyketone, and an adhesive in contact with said layer, wherein the adhesive is a plastomer wherein said plastomer is a random copolymer of ethylene or propylene, the tape comprises an ultra-high molecular weight polyethylene. The composite panel is used in a ballistic resistant article.

U.S. Patent Publication 2015/0222011 relates to composite radome wall structures exhibit both antiballistic and radar transparency properties and include an antiballistic internal solid, void-free core and external antireflective (AR) surface layers which sandwich the core. The antiballistic core can be a compressed stack of angularly biased unidirectional polyethylene monolayers formed of tapes and/or fibers. Face sheets and/or one or more impedance matching layers may optionally be positioned between the antiballistic core.

U.S. Patent Publication 2016/0178327 relates to ballistic resistant sheets and articles such as curved ballistic resistant armor and helmets. The ballistic resistant sheets are a multi-layer monolayer construction including a core layer having first unidirectional oriented reinforcing fibers and an elastomeric material sandwiched between the face layers.

U.S. Patent Publication 2016/0380345 relates to composite anti-ballistic radome walls that have radar transparency properties and include an anti-ballistic internal solid, void-free core and external antireflective surface layers which sandwich the core.

SUMMARY OF THE INVENTION

The present invention relates to wall construction comprising a laminate of multiple layers of fabric or tape made of axially-oriented elongated thermoplastic fibers, where the flat fabric shapes, layup geometry, and the final radome thickness are simultaneously optimized for (a) the radome final shape, (b) multiple radio frequencies transparency, (c) withstanding impact by blunt objects and ballistic projectiles, and (d) resistance to absorb water.

The present invention relates to a rugged radome closure that is transparent to radio frequency electromagnetic radiation and provides impact and ballistic protected interior space.

The present invention involves the fabrication processes by which rugged radome closures are fabricated of materials that are commonly applied to light-weight ballistic protection armor. These ballistic materials and the processes to convert them into radome shapes differ from conventional radome materials and associated fabrication processes.

It is an object of the present invention for common thermoplastics used in the present invention to be comprised of High Density Polyethylene, Ultra High Molecular Weight Polyethylene, Polypropylene, Aramid and any combination thereof.

It is an object of the present invention to produce complex curvature radome closures, the choice material fabric or tape is cut into unique two dimensional (flat) shapes. The flat shapes are laid into a three dimensional mold to yield a desired near-net-shape three dimensional complex curvature radome closure after consolidation.

It is an object of the present invention for the consolidation of layers into a solid laminate to be accomplished by exposing the layers to pressure or a combination of pressure and temperature. The consolidation pressure may be generated by compression molding, vacuum, a pressurized vessel, or similar methods.

The present invention comprises a rugged radome that comprises a radome shell, an adhesive/sealant, a lower ring, an upper ring and a sealing gasket. It is an object of the present invention for the rugged radome to further comprise a ring assembly screw.

The present invention comprises a rugged radome having a radome shell, an adhesive/sealant, a lower ring and an upper ring, a sealing gasket and a mounting screw.

The present invention encompasses a rugged radome system that comprises a radome shell, an adhesive/sealant, a lower ring, an upper ring, and a sealing gasket.

The present invention is a method for making three-dimensional high contour structures and shapes that do not have a draft angle, or can curve back upon themselves, made of linearly oriented thermoplastics. In addition to having the shapes and features, the created linearly oriented thermoplastic composite has properties and or features that facilitate structural attachment to create larger assemblies. The inherent properties of the structure can be rugged and able to resist projectiles, shrapnel, and over-pressure blasts.

The present invention relates to producing a rugged radome closure that has a spherical portion and a cylindrical portion with a joggle at the base. These features preclude pressing or filament winding manufacturing methods to manufacture ruggedized and ballistic protective closures, but are not limited to only the manufacturing method. It is an object of the invention for the method to be used for items that can also be filament wound or pressed. It is an object of the present invention for the joggle to be at 90°.

The present invention involves fabrication processes by which rugged radome closures are fabricated of materials that are commonly applied to light-weight ballistic protection armor. These linearly oriented thermoplastic materials and the processes to convert them into radome shapes differ from conventional radome materials and associated fabrication processes.

The fabrication process utilized an autoclave or like process that contains the ply stack. The ply stack is laid up on a net shape tool. The two-dimensional material is darted and nested with many other layers that provide a near even thickness of linearly oriented thermoplastic material. This ply stack is then contained or isolated from the atmospheric air by a vacuum bag, flexible caul, inflatable mandrel or similar gas barrier. The autoclave or like process then reduces pressure within the ply stack relative to the pressure vessel atmosphere. This may be accomplished by applying vacuum to the stack or applying pressure to the pressure chamber environment, inflating a Blatter or mandrel, thus creating a pressure differential across the gas barrier. The vacuum bag or pressure isolation material does not necessarily have to be removable and can be ride-away tooling or an inner or outer coating.

It is an object of the present invention for common thermoplastics used in the present invention to be comprised of High Density Polyethylene, Ultra High Molecular Weight Polyethylene, Polypropylene, Aramid and any combination thereof.

It is an object of the present invention to produce complex curvature radome closures, the choice material fabric or tape is cut into unique two-dimensional (flat) shapes. The flat shapes are laid into a three dimensional mold to yield a desired near-net-shape three dimensional complex curvature radome closure after consolidation. It is an object of the present invention for the consolidation of layers into a solid laminate to be accomplished by exposing the layers to pressure or a combination of pressure and temperature. The consolidation pressure may be generated by compression molding, vacuum, a pressurized vessel, or similar method.

The present invention relates to utilizing a joggle, or feature that is out of plane with a surface being retained, that allows a linearly oriented thermoplastic structure to be retained into an adjacent assembly. It is an object of the present invention for the joggle to be designed in a manner that if needed, seals water tightness, air tightness, and resistance to sand and dust. The present invention relates to linearly oriented thermoplastic structures attached to a surface to create a weather tight raggedized closure.

It is object of the present invention for common thermoplastics used in the present invention to be comprised of High Density Polyethylene, Ultra High Molecular Weight Polyethylene, Polypropylene, Aramid or any combination thereof.

Figure 1 shows an embodiment of a radome device of the present invention.

Figure 2 shows an embodiment of a radome device of the present invention.

Figure 3 shows an embodiment of a rugged radome system assembly of the present invention. Figure 4 shows an embodiment of a top ring of a rugged radome assembly of the present invention.

Figure 5 shows an embodiment of a lower ring of a rugged radome assembly of the present invention.

Figure 6 shows a RCOTM workflow diagram.

Figure 7 shows a Manufacturing workflow diagram. Figure 8 shows a three-dimensional high contour structure.

DETAILED DESCRIPTION

Figure 1 shows the ragged radome 10 having a radome shell 12, and an adhesive/sealant

14. The radome has a lower ring 16 and an upper ring 22. The radome further comprises a sealing gasket 18 and a ring assembly screw 20.

Figure 2 shows the rugged radome 30 having a radome shell 32 and an adhesive/sealant

34. The radome has a lower ring 36 and an upper ring 42. The radome further comprises a sealing gasket 38 and a mounting screw 40.

Figure 3 shows a ragged radome system assembly. Radome 50 is comprised of a radome shell 51, top ring 52 and a lower ring 53. The radome 50 further comprises a gasket 54, polyurethane adhesive 55, and a screw 56. The radome 50 further comprises a Polane S Plus 57, clear primer 58 and a Polane Spray 59.

Figure 4 shows different views of the top ring 70. In an embodiment, the top ring 70 is made of an aluminum alloy. The top ring 70 has a tapped hole 72.

Figure 5 shows different view of the lower ring 80. In an embodiment the lower ring 80 is made of an aluminum alloy. The lower ring 80 has a screw hole circle 82.

Figure 6 shows a flow chart wherein at first stage 110 a tool type is made of any shape and composed of any material. In second stage 120, the tool is contoured including any complex curvature and draft angles. In a preferred embodiment the curvature and draft angles are greater than 90°. In stage 130, a parent material comprised of plies of two dimensional linearly oriented thermoplastic is gored or cut to conform to the tool surface. In stage 140, the material is formed by having multiple layers of the linearly oriented thermoplastic stacked to mark the required composite structure. In stage 150 there is consolidation where temperature is applied and consolidation is achieved utilizing a vacuum bag and pressure differential in an apparatus such as an autoclave.

Figure 7 shows a manufacturing workflow diagram where in Step 200 a tool is manufactured and-'or prepped for layup. In Step 210 a two-dimensional material is cut to conform to a three-dimensional shape. Multiple patterns can be used. In Step 220, a twodimensional material is laid up on a tool. Debulking and intermediate consolidations may be used to maintain part of the shape and contour. In Step 230, a vacuum bag or a gas barrier material is applied to isolate the composite stack from the local atmosphere. In Step 240, heat is applied and in the circumstance of an autoclave, vacuum is applied to the part or vented to the atmosphere while high pressure is accumulated in the local atmosphere to create a pressure differential that consolidates the composite stack against the tool surface.

Figure 8 shows a three-dimensional high contour structure that comprises a linearly oriented thermoplastic composite 300, a sealant/stress normalization layer 310, a segmented capture ring 320 and a continuous ring 330 for attachment to a larger assembly.