Abstract:
A composite structure, and method of manufacturing it, having a specified width, length, and height defining a top and bottom the composite structure. The composite structure includes a three dimensional structural core constructed of a polymer with a first series of a geometric pattern repeated along its length. The structural core also has a second series of the geometric pattern repeated along the width thereof. The geometric patter may be a sinusoidal curve or a substantially pyramidal shape. The composite structure also includes a first reinforcement layer made of a polymer positioned above the structural core and bonded thereto. It also includes a second reinforcement layer made of a polymer that is positioned below the structural core and bonded thereto. The composite structure may also include a decorative layer above the first reinforcement layer, an acoustical batting layer positioned between the first reinforcement layer and the structural core, and may include fire retardant chemicals.

Description:
CLAIM OF PRIORITY AND CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. patent application Ser. No. 11/973,243, filed on Oct. 5, 2007, now U.S. Pat. No. 7,857,934, which is a Divisional of U.S. patent application Ser. No. 10/352,803, filed on Jan. 28, 2003, now U.S. Pat. No. 7,297,390, which claims priority to U.S. Provisional Application No. 60/352,707, filed Jan. 28, 2002, all of which are incorporated herein by reference in their respective entireties. 
    
    
     BACKGROUND 
     Field of the Invention 
     Structural polymer technology has existed for many years and has been applied periodically in the automotive industry, among a myriad of other industries. A few typical applications, using the automotive industry as an example, include:
         energy absorbing countermeasures to meet Motor Vehicle Safety criteria (eg: FMVSS 201);   glass matte (chopped fiberglass in the form of a laminar web) impregnated with thermoplastics and used in load floors and paneling;   clamshell-type sunvisor cores;   vacuum formed returnable packaging trays;   underhood components, such as battery trays; and   body components such as glass-reinforced bumpers.
 
A few advantages of structural polymers include:
   high dimensional accuracy;   extremely repeatable physical properties;   thermal stability;   fully thermoplastic characteristics;   completely recyclable;   steady supply stream;   known and repeatable processing methods;   cost savings potential; and   capable of being modeled mathematically to estimate mechanical, acoustical and/or thermal characteristics.
 
Obviously polymers are well integrated as structural components for both interior and exterior automotive applications. However, many of the existing applications today are limited from achieving full potential due to the particular processing method, polymer used, or the physical structure of the polymer itself. Injection molding, vacuum forming, and compression molding represent the primary means of processing structural polymers.
       

     It has been discovered that a specific structural polymer core assembly is very advantageous, and superior over the prior art, for use in the automobile industry, specifically automobile interior headliners. It should be understood that while the structural assembly disclosed herein was developed specifically as automobile interior headliner, the assembly has a wide variety of other uses in other industries such as aviation, marine, building construction, office furniture, material handling, kitchen appliances, etc. Thus, while the following description will address the advantages of the structural assembly over the present technologies used in automobile headliners, it will be readily apparent to one of ordinary skill that the advantages of the structural assembly may be applicable to many industries and applications. Therefore, the following description in no way limits the scope of use of the present invention to automotive headliners. 
     Typically in the automobile industry, headliners are made as a composite laminate containing a plurality of layers. As seen in  FIG. 1 , a typical headliner may be made of the following layers from the bottom-up:
         a first non-woven scrim  2 ;   a first film of polymer  4 ;   a layer of chopped fiberglass  6 ;   a second film of polymer  8 ;   a foam core  10 ;   a third film of polymer  12 ;   a second layer of chopped fiberglass  14 ;   a fourth film of polymer  16 ; and   a second non-woven scrim  18 .
 
The interior-facing side of the headliner is then covered with a decorative fabric for mainly aesthetic purposes. The headliner is then formed into the shape of the interior roof of the automobile for which it to be installed.
       

     These types of headliners suffer from a number of drawbacks in that they are (1) expensive, (2) have relatively low strength, (3) tend to sag when under extreme environmental conditions for an extended period of time (i.e., they have low environmental resistance), and (4) have relatively low acoustical absorption. Also, to comply with the new Federal Motor Vehicle Safety Standards (eg: FMVSS 201), these headliners must sometimes be augmented with counter-measures after installation to provide for greater energy absorption to help prevent injury to a motorist in the case of an accident. This adds cost to the installation process. 
     It would thus be advantageous to provide a structural material with low cost, high strength, high environmental resistance, and high acoustical absorption that does not have to be so augmented after installation to comply with Federal safety standards. 
     SUMMARY OF THE INVENTION 
     To create the structural polymer of the present invention, a sheet of polymer, either unreinforced or reinforced with a reinforcing agent such as, but not limited to, fiberglass, is formed into a 3-dimensional structural core such as a repeating sinusoidal, pyramidal, honeycomb, or other repeating pattern as discussed in further detail below. The 3-dimensional shape formed is a series of repeating peaks and valleys. This may be accomplished in a variety of ways discussed below. The structural core is then sandwiched between two reinforcement layers that may be constructed of various materials. These reinforcement layers are preferably constructed of a material compatible with the polymer used to make the structural core to facilitate bonding between the structural core and the reinforcement layers without the addition of unnecessary external bonding agents. The reinforcement layers are preferably applied and bonded to the structural core using a double-belt laminator prior to subsequent conversion of the assembly into the final form of the construction. However, one of ordinary skill will realize the variety of ways known in the art by which this may be accomplished. For applications requiring a predominantly flat substrate, a pre-heating cycle followed by a compression cycle in a matched set of temperature regulated tooling may be employed to join the components the 3-dimensional structure. A batting layer may be sandwiched between the structural core and the reinforcement layers filling the gaps created when the structural core was formed. Other reinforcing and decorative layers may be applied to the resulting composite. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       A more complete understanding of the method, apparatus, and article of manufacture of the present invention may be obtained by reference to the following detailed description when taken in conjunction with the accompanying Drawings wherein: 
         FIG. 1  is a side elevational exploded view of a typical headliner composite; 
         FIG. 2  is a perspective view of one embodiment of the structural core of the present invention; 
         FIG. 3  is a perspective view of one embodiment of the structural core of the present invention; 
         FIG. 4  is a perspective exploded view of a structural polymer core assembly of the present invention; 
         FIG. 5A  is an elevational cross sectional view of the structural polymer core assembly of  FIG. 4 ; 
         FIG. 5B  is an elevational cross sectional view of a structural polymer core assembly concept employing the structural core of  FIG. 3 ; 
         FIG. 5C  is an elevational cross sectional view of an alternative embodiment of a structural polymer core assembly employing the structural core of  FIG. 3 ; 
         FIG. 6  is a perspective view of a molding machine that may be used to form the structural core of the structural polymer core assembly; 
         FIG. 7  is a perspective view of the plates of the molding machine illustrated in  FIG. 6 ; 
         FIG. 8  is a perspective view of alternate plates of the molding machine illustrated in  FIG. 6 ; and 
         FIG. 9  is a perspective view of a continuous structural core forming machine used to create the structural core of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIG. 2 , a perspective view of one embodiment of the structural core  20  of the present invention is shown. The structural core  20  is formed of a pattern of repeating geometries forming peaks  22  and troughs  24 . In this illustration, the repeating geometries formed are sinusoidal curves. The actual measurements and properties of the structural core  20  are driven by various design parameters such as mass, compressive strength, acoustical behavior, environmental resistance, core target cost at nominal thickness, etc. Thus, by varying the thickness, geometry, and material of the structural core  20 , one can optimize the various design parameters associated therewith. Various base materials considered for the structural core  20  for use in the automobile headliner industry are: (1) a fiber-reinforced recycled thermoplastic composite as disclosed in U.S. Pat. No. 6,271,270 B1; (2) a fiber-reinforced recycled thermoplastic composite as disclosed in U.S. Pat. No. 6,387,967 (3) polypropylene; (4) polyethylene terephthalete; (5) polyamide (nylon); (6) thermoplastic polyolefin; and (7) high density polyethylene. Reinforcing fibers, such as fiberglass, natural fiber, monofilament polymer, and P.E.T. fiber, may be employed within the base material for reinforcement purposes. 
     In addition to the criteria outlined above, additional design guidelines may be used or targeted once the initial geometry is established such as:
         interval of repeating pattern;   nominal core weight/area;   nominal core height or effective core thickness;   minimum contact area with reinforcement layers at peak of geometry;   maximum draw angle;   resin type (for applicable material); and   maximum reinforcement fiber length (for applicable materials).
 
There are inherent benefits to using a structural core  20  which is 3-dimensional as compared to just a flat sheet of polymer such as: (1) lower density; (2) higher strength to weight ratio; and (3) greater acoustical absorption potential (due to the greater surface area and the non-perpendicular reflections of incident sound waves and the abatement associated with them). These inherent benefits would apply to any structural core design in which a geometry is rendered which comprises a vast majority of air and only a small volume of polymer (or composite). When the structural core is designed appropriately and efficiently, and when it is combined with appropriate reinforcing layers, as in the examples herein proposed or as in more traditional honeycomb structures, tremendous strength and flexural modulus can be achieved. The additional advantage of forming such a geometry from an initially flat thermoplastic sheet in a relatively simple process is that such a construction will have significantly lower cost of assembly than traditional means of employing extruded or heat-staked honeycombs or adhesive-bonded honeycomb structures.
       

     Referring now to  FIG. 3 , there is shown a perspective view of one embodiment of the structural core  21  of the present invention. The structural core  21  is formed of a pattern of repeating geometries forming peaks  23  and troughs  25 . In this embodiment, the repeating geometries formed are modified pyramidal shapes that are characterized by a unique symmetry which facilitates the production of such features in an initially flat thermoplastic sheet. In order to provide sufficient contact area for bonding between the structural core  21  and any reinforcement layer, the peaks  23  and troughs  25  have flat tops and bottoms. In order to reduce stress concentration factors and assist in compression forming, appropriate radii have been assigned to the areas of the geometry where oblique edges join each other. It has been found that the particular geometry of the structural core  21  of  FIG. 3  has excellent acoustical absorption properties in the 500-2000 HZ range. Other geometries may be used for the structural cores  20 ,  21  such as egg-crate shapes, a honey-comb pattern, etc. 
     Referring now to  FIG. 4 , there is shown a perspective exploded view of the structural polymer core assembly  100  of the present invention. To provide stability of the structural polymer core assembly  100 , the structural core  20  is sandwiched between reinforcement layer  40  and reinforcement layer  30 . In order to provide for additional acoustical absorption, acoustical batting  32  may be sandwiched between the reinforcement layer  40  and the structural core  20 . Similarly, acoustical batting  32  may also be placed between reinforcement layer  30  and structural core  20 . For aesthetic purposes, the outside of reinforcement layer  40  may be covered with decorative fabric  42 . To allow for good bonding between the structural core  20  and the reinforcement layers  40 ,  30 , the reinforcement layers  40 ,  30  should be constructed of a material compatible with the material of the structural core  20 . It should be noted that dissimilar materials may also be employed if necessary but may require the introduction of an adhesive layer or other bonding agent. 
     Still referring to  FIG. 4 , due to the nature of the structural polymer core assembly  100 , a specific three step process can be employed to create it, however, in actuality a plurality of methods exist to produce said assembly. In the specific three step process referred to, a flat sheet of polymer (optionally reinforced polymer) is first pre-formed into a 3-dimensional structural core  20  of substantially uniform thickness. Methods of pre-forming the structural core  20  will be discussed in further detail below, and like the structural polymer core assembly  100 , the structural core  20  can be created using several various methods. The second step in the assembly process is to create a flat composite which incorporates the structural core  20  between two reinforcement layers  40 ,  30 . This composite may be laminated using a double belt laminator. The resulting composite would have substantially uniform thickness and would resemble the basic design for  FIG. 5A . Another embodiment and method would be to fuse the core  20  to the reinforcement layers  40 ,  30  by applying local heating or welding at predetermined locations  34 ,  44  in the form of a conductive heat mandrill, vibration or sonic welder, or other similar thermoplastic fusing means as generally illustrated in  FIG. 5C . The final step is to preheat the composite in a convection or radiant style oven, soak the materials at a temperature to achieve the proper forming properties, add decorative fabric  42  to the outside of reinforcement layer A  40 , and index the structural polymer core assembly  100  into a cool forming tool which molds the assembly into the shape of a particular finished composite structure 
     Referring again to  FIG. 5A , there is shown an elevational cross-sectional view of a structural polymer core assembly  100  of  FIG. 4 . To provide stability, the structural core  20  has been sandwiched between two reinforcement layers  30 ,  40 . To provide for increased sound absorption, a layer of batting  32  has been sandwiched between the structural core  20  and the reinforcement layer  40 . For aesthetic purposes, the outer surface of the reinforcement layer  40  has been covered with decorative fabric  42 . After forming, the structural polymer core assembly  100  may be formed into a particular shape depending on the application for which it is intended. For example, the structural polymer core assembly  100  may be drawn into the shape of an automobile headliner. When a headliner is formed, the structural core  20  of the structural polymer core assembly  100  in the drawing area  200  may collapse somewhat into a more flat geometry. The 3-dimensional structural core  20  geometry allows for more “give” in the core material and allows for a deeper draw than that of flat polymer made of the same material and of the same thickness. A geometrical structural core  20  pre-formed sheet can replace more expensive or undesirable materials such as urethane foam, resinated fiberglass, or cardboard (materials typically used as core materials in headliners and other decorative substrates with either structural or functional requirements). The structural polymer core assembly  100  illustrated has several features that are evident from the illustration. First, air cavities between structural core  20  and reinforcement layer  30  allow entrapment and absorption of incident sound. Second, the bond between structural core  20  and reinforcing layers  30 ,  40  requires no additional adhesive, when these materials are selected in such a way that they are compatible Third, the 3-dimensional structural core  20  construction offers transverse strength as compared to typical headliners used in the industry. 
     Lastly, with the advent of new and more strenuous motor vehicle safety regulations (e.g. FMVSS 201), additional requirements have been added to the functionality and purpose of a headliner module. The requirement that appears to have changed the design of a typical headliner the most is the head-impact requirement. This regulation imposes a minimum acceptable energy absorption capability upon the headliner in specific target zones. Traditional methods of reaching this minimum level of absorption have required extensive counter measures, typically applied after forming, to the rear surface of the substrate. This process is costly, labor intensive, and requires additional packaging space within the vehicle cockpit. The concept of a structural polymer core assembly  100  not only addresses the traditional requirements of an automobile headliner, but also promises to help address the issue of energy absorption. Due to its geometry, a structural core  20  would naturally absorb energy at a very efficient rate and level. This is due to the collapsing of the 3-dimensional shapes without rebounding when an impact force is applied. 
     A significant capability related to these four features is the simulation of design and mathematical modeling that can validate such properties in relationship to one another prior to prototyping of the actual structure. A design whose properties can be estimated, analyzed and/or optimized mathematically promises a great advantage over traditional methods of designing composite structures employing core materials such as urethane foam or cardboard which are by nature have much greater variations than do polymers of known and repeatable physical properties. The inherent design of a predictable structure can lead itself to efficient analysis and design enhancement as will be described in greater detail below. 
     Referring now to  FIG. 5B , an elevational cross sectional view of a structural polymer core assembly  100  employing the structural core  21  of  FIG. 3  is shown. The embodiment here depicted is a simple three layer assembly consisting of the structural core  21  of  FIG. 3 , sandwiched between reinforcement layers  30  and  40 . As stated above, optional acoustical batting may be used between either reinforcement layer  30 ,  40  and the structural core  21 . Also, a decorative fabric may be added to the outside surface of either reinforcement layer  30 ,  40 . 
     Referring now to  FIG. 5C , an elevational cross sectional view of an alternative embodiment of a structural polymer core assembly  101  employing the structural core  21  of  FIG. 3  is shown. Structural polymer core assembly  101  is similar to the structural polymer core assembly  100  of  FIG. 5B  except for openings  33  and  43  spaced throughout the planar surface of the reinforcement layers  31  and  41 , respectively. Openings  33  and  43  allow heated mandrills  35  to pass through openings  33  and  43  and apply heat and pressure to area  45  where the structural core  21  comes into contact with reinforcement layers  31  and  41 . When heat and pressure is applied to area  45 , structural core  21  bonds to reinforcement layers  31  and  41  without the aid of an adhesive or other bonding agent (as long as the material of the structural core  21  is compatible with the materials of the reinforcement layers  31  and  41 ). The openings  33  and  34  also function to help the structural polymer core assembly  101  operate to function as a sound absorption structure. 
     Referring now to  FIG. 6 , there is shown a perspective view of a molding machine  110  that may be used to form the structural core  20  of the structural polymer core assembly  100 . To form the structural core  20 , a flat piece of polymer (which may be fiber reinforced) is initially pre-heated using radiant or convective means and subsequently placed between plates  114 ,  115  that are preheated to a temperature specified at the control panel  112 . The plates  114 ,  115  are then brought together compressing the flat piece of polymer into the 3-dimensional shape of the structural core  20 . The amount of compressive force on the plates  114 ,  115  and the length of time they are brought together are controlled at the control panel  112 . The plates  114 , 115  remain together for a period of time long enough for the polymer to cool adequately and produce a structurally sound structural core  20 . 
     Referring now to  FIG. 7 , there is shown a perspective view of the plates  114 , 115  of the molding machine  110  of  FIG. 6  illustrating the surface geometry of the plates  114 , 115  used to form the structural core  21 . As is evident from  FIG. 7 , the interior surfaces of the plates  114  and  115  mate to form the specific geometrical pattern of the structural core  21 . To form the peaks  23  and troughs  25  of the structural core  21  (see  FIG. 3 ), the plates  114 ,  115  have corresponding peaks  116  and troughs  118  on their interior surfaces. The plates  114 , 115  illustrated are of a geometry to form the pyramidal structural core  21  of  FIG. 3 . Such geometry has been designed to allow a natural nesting of upper plate  114  with lower plate  115 . This nesting is critical to the symmetry of the resultant formed structural core  21  about its neutral axis and will allow a clear understanding of the anisotropic mechanical properties in structural core  21 . 
     Referring now to  FIG. 8 , there is shown a perspective view of alternate plates  124 ,  125  of the molding machine  110  illustrated in  FIG. 6 . These plates  124 ,  125  are configured to generate the sinusoidal-type structural core  20  illustrated in  FIG. 2 . To generate the sinusoidal-type geometry, the peaks  116  of plates  124 , 125  are rounded to form the peaks  22  and troughs  24  of the structural core  20 . Any number of plates  124  and  125  with different geometries may be used to generate a wide variety of structural core shapes. 
     Referring now to  FIG. 9 , there is shown a perspective view of one embodiment of a continuous structural core forming machine  200  used to create the structural core  20  of  FIG. 2 . To continuously form a structural core  20  (not shown), a flat piece of polymer (which may be fiber reinforced) is initially preheated and then placed between two opposing belts  206  (note that only one belt is illustrated in  FIG. 9 ) which contain the appropriate forming geometry. Each belt  206  contains rows  204  of raised areas  202  that intermesh with the raised areas  202  of the opposing belt  206  (not shown). As the belts move, the piece of polymer is drawn down the belt while being formed into the pre-determined shape of the structural core  20 . The continuous structural core forming machine  200  may have heating zones to bring the polymer to the proper forming temperature, or, alternatively, the material may be preheated in an oven, or the like. Similarly, the continuous structural core forming machine  200  may have a cooling zone to bring the formed structural core  20  to a temperature such that it is structurally sound when coming off the continuous structural core forming machine  200 . The continuous structural core forming machine  200  illustrated in  FIG. 9  is configured to form the structural core  20  of  FIG. 2 , however, by varying the geometry of the raised areas  202 , the continuous structural core forming machine  200  can easily be configured to form structural cores with a variety of geometric patterns. 
     In addition to the method for continuously forming the structural polymer core as illustrated in  FIG. 9 , a few additional methods are conceived. In one such method, specialized rollers are created with specific surface geometry design to nest with one another in much the same way meshing gears would join. The polymer sheet (which may be reinforced) is initially preheated and then introduced into the 3-dimensional meshing area of the mating rollers. The rollers would serve to consolidate the shape by virtue of the application of compression and controlled cooling. Other methods for continuously forming said polymer core include a vacuum thermoforming process and an air bladder blowing process. 
     Once the structural core  20  is pre-formed, it can then be laminated into a pre-applied composite sandwich to form sufficient bond strength between the various layers of the structural polymer core assembly  100  and to assist handling during the final forming step. Lamination of composite layers is standard procedure for producing automotive headliners of the dry thermoplastic type whether the cores are made of semi-rigid foam, polyethylene terephthalete, or some variant of glass-matte thermoplastic, etc. Lastly, the structural polymer core assembly  100  is formed into the shape of a headliner using heat and pressure, a process very well known in the art. 
     Previously, automobile interior trim (such as headliners) have not been historically developed using computer aided design such as finite element analysis. One reason for this is that the materials used in constructing the “old” interiors had variable properties due the types of materials used in their construction. Urethane foam or fiberized nonwovens are irregular and difficult to model theoretically. Large material variations exist making it very difficult, if not impossible, for a computer to predict material behavior analytically (such as compressive strength, transverse bending values, acoustical behavior, etc.). Through the use of computer simulation, materials with consistent properties, and the variation of structural core  20  geometry, engineers can actually tailor a polymer structural core geometry to:
         attenuate specific frequencies of sound;   deflect to known amounts in quantifiable ways;   withstand various environmental conditions; and   absorb a particular amount of impact energy.
 
Not only does one have the capability to develop an intelligent design, but one can also create and analyze numerous virtual designs analytically with the use of design analysis software. This can be done at a fraction of the cost, a fraction of the time, and with greater accuracy than the traditional “trial and error” method.
       

     By its very nature, a structural polymer core assembly like the one described herein can be a building block and/or modular component of larger system when integrated into appropriate applications. Attributes of the design which validate this statement include its structural integrity, theoretical capabilities to abate unwanted noise, high strength-to-weight ratios, low relative cost, simplicity of construction and efficiency of design as well as other features aforementioned. Several specific methods of utilizing the structural polymer core assembly in the interest of realizing the previously mentioned attributes will be described in detail in the following paragraphs. 
     Due to the stringent yet diverse requirements of automotive interior components, materials and structures are required which represent an optimization of such important characteristics as, for example, flexural strength and acoustical absorption. Often the composition of a structure that has strong mechanical properties must sacrifice some level of acoustic damping and vice versa. When impact absorption, cost, and manufacturing feasibility are added to the list of requirements, it is apparent that automotive interior component design relies upon a vast balance and prioritizing of key attributes. For this and other reasons, the structural polymer core assembly  100 ,  101  appears to address such optimization considerations quite well. For example, the structural polymer core assembly  100 ,  101  could be integrated into an automobile in the following ways: as a headliner, a “package tray” (or speaker shelf), the substructure of a visor, a cargo area or trunk load floor, a seat back or door bolster reinforcement, a console tray, etc. 
     Unlike the automotive interior example, building constructions applications are typically more strictly concerned with mechanical properties of the building materials in addition to their cost. A structural polymer core assembly  100 ,  101  could be designed to share many of the same functional properties as are common to materials like plywood or particle board. Certain manifestations of the design may even satisfy the requirements of structural elements made out of lumber. As such, the structural polymer core assembly may be used for decking, roofing, walls for buildings or vehicles, supporting concrete during the pouring and curing steps as in a wall of concrete. Additionally said assembly could be integrated into material handling components such as pallets and containers. 
     It is thus apparent that the structural polymer core assembly  100 ,  101  could serve the function as the structure inside a door. It would meet the mechanical requirements of such an application, while adding the capability of acoustical and thermal insulation, as well as efficiency of design and cost. 
     Marine applications require yet another set of optimized performance characteristics to which the structural polymer core assembly  100 ,  101  seems well suited. Among these are salt and corrosion resistance, buoyancy, thermal insulation by virtue of either entrapped air or the introduction of specialized insulators into the structural polymer core assembly  100 ,  101 , and environmental stability. The assembly could serve as a portion of the decking of a boat, or a component of the substructure, or as an insulator for a marine vehicle engine, or separately as a component of a dock or pier. In addition to external marine applications, it is readily apparent that the attributes of the structural polymer core assembly  100 ,  101  that make it well disposed in meeting the requirements of an automotive interior would thus satisfy similar requirements of certain aspects of a marine vehicle interior. 
     Aircraft applications are obviously concerned with strength-to-weight attributes and the efficiency of utilizing light materials that will perform in an environment typical of an aircraft. Again it is clear that the structural polymer core assembly  100 ,  101  could be so designed and manufactured to meet the requirements of such aircraft applications as the following: a drink tray capable of being stowed; certain components of a drink cart such as the sides and substructure; certain components of storage areas such as the overhead bins, elements of the galley, luggage compartment or lavatory, as a component in bulkhead walls or privacy partitions. Additionally, given the appropriate design a structural polymer core assembly  100 ,  101  could serve to function as an element of an aircraft flooring. 
     Kitchen appliances or other kitchen applications may also require properties that may be met with a structural polymer core assembly  100 ,  101 . Examples include components of appliance surfaces and structures where reinforced cores are prevalent, shelving, and as a structural component within countertops and cabinetry. Additionally, if the structural polymer core assembly  100 ,  101  (the core and the reinforcement layers) is comprised of a metal such as aluminum or stainless steel, it may even meet the requirements of a cooking surface as in a cooking sheet by allowing a more even heating of the surface than a flat sheet would otherwise permit. 
     Applications whereby the structural polymer core assembly  100 ,  101  could meet the needs of certain components of furniture are legion. As noted above for the kitchen applications, the structural polymer core assembly  100 ,  101  could provide a substructure under a decorative paneling, for example as a core for a laminated book shelf or veneered table. Additionally, portions of this concept could be applied to seating. Some of the performance characteristics of furniture applications are similar to those of automotive and marine interiors such as decorative layers that offer aesthetic value, fabric backings that serve tactile or acoustical purposes, structural components that add integrity, as well as efficiency of design and economics. Structural polymer core assembly designs could also be utilized for a myriad of office furniture applications. Among these are office partitions. Partitions or cubicle walls demand an interesting set of aesthetic and functional properties. Among these is the absorption of ambient noise in an environment where individuals work independently yet within a common work area. In order to meet this need, a structural polymer core assembly  100 ,  101  could be introduced which utilizes several strategies to reduce these ambient noise levels. For example, an assembly could be designed with a series of perforations (thus enabling the entrapment of specific frequencies); yet said assembly could incorporate a layer of soft and flexible batting by which to further dampen the incident sound waves. Finally the nature of the structural core  20 ,  21  itself affords a greater surface area than a flat core component, and is characterized by a large percentage of airspace relative to the volume of the structural core  20 ,  21 . These potential countermeasures could work in unison to provide a unique solution to an industry demand. The structural polymer core assembly  100 ,  101  could simultaneously meet the other rigorous requirements typical of office furniture such as fire retardance, modularity of components, strength and durability, to name just a few. 
     For the various methods of utilizing a structural polymer core assembly  100 ,  101 , some of which but not all have been outlined in the paragraphs above, numerous geometries can be conceived and even optimized for specific applications depending upon the relative priority of performance requirements. 
     It is thus believed that the operation and construction of the present invention will be apparent from the foregoing description. While the method and apparatus shown or described has been characterized as being preferred it will be obvious that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the following claims: