DESCRIPTION OF THE PREFERRED EMBODIMENT

[0196] The CWCV shown in FIGS. 13-22 show a fiber pattern that is generally sinusoidal with a constant wave form, period, etc. Since the damping properties are frequency and temperature dependent, and since the selection of an optimal wave shape can be influenced by the desired structural response, a non-periodic, non-sinusoidal wave shape may be the preferred optimal CWC. There are other variables such as selection of materials, relative thickness of laminates, etc., not shown or discussed below that are important for correct design in addition to selection of wave shape, etc. The selection of these details will be necessarily customized for different designs and will be obvious to one skilled in the art. The discussions below are intended to illuminate the general design of CWCV that will be common to most CWCV structures and that will result in optimal strength, damping and stiffness. Therefore, wave shapes, relative sizes and thickness of component laminates, etc., will require analysis by the designer based on the desired structural response. The representations of these design parameters in FIGS. 13 through 22 are exemplary only.

Basic CWCV Plate

[0197] The CWCV plate is the most basic unit built with these new materials. It can be shaped and bent to make stiffener building blocks. CWCV plates, stiffeners and cores cab be combined in any combination to form intermediate structural members. The intermediate structural members can be combined with additional CWCV building blocks to form larger structures.

[0198] FIG. 13a is a plate with two layers of CWC and an intermediate layer of viscoelastic and represents any combination of waveforms shown in FIGS. 1-5. The CWC layers may be made with bi-directional cloth as well as unidirectional fibers.

[0199] In FIG. 13a the plate (1) is comprised of two CWC laminates of opposing wave forms (4 &5) constraining a viscoelastic layer (2). In FIG. 13a-1 two of the laminates shown in FIG. 13a are combined without a viscoelastic layer in between so that the CWC laminates which are bonded together without the benefit of a viscoelastic layer are of a matched waveform (Item 5). The laminate representation is (4)/(2)/(5)/₂(2)/(4) where the number in parenthesis represents the material type as discussed above, and the subscript denotes the number of laminates of the indicated type. It has been found that balancing a multi-laminate CWCV plate in this manner gives the most efficient damping and strength performance. Two or more plates as shown in FIG. 13a-1 can be combined to form thicker laminates as shown in FIG. 13a-2 (6).

[0200] The CWCV plate shown in FIG. 13a has its primary damping properties along the direction of the fiber pattern. The transverse damping properties are not as pronounced. FIG. 13b is a way of combining two CWCV laminates oriented at different angles with respect to each other and bonded by a viscoelastic layer. This allows the engineer and designer to design structures with efficient damping properties in more than one direction. The example shown in FIG. 13b shows two CWCV plates oriented at 90° with respect to each other. Items 4, 2, and 5 from FIG. 13a are combined with an additional viscoelastic layer (2) and another laminate (4a, 2, 5a) which are oriented in a different direction.

[0201] The laminate in FIG. 13b, provides efficient damping in more than one direction but represents an unbalanced ply laminate. The plate shown in FIG. 13c is a way of combining four CWCV plates with the top and bottom plates oriented in the same direction and the intermediate two plates oriented in another direction. Of course it is possible to combine multiple plates as shown in FIG. 13a, 13a-1 and 13a-2 in various directions to provide efficient damping and strength properties according to the design goals of the engineer.

[0202] FIG. 13d shows a CWC laminate (4) combined with viscoelastic materials (2) and conventional materials (7) which can be composed of traditional cross-ply laminates, isotropic materials, plastics, or other materials according to the design criteria of the engineer. In this case the conventional materials are shown constraining a central CWC laminate.

[0203] FIG. 13e shows the same basic structure of 13d but instead of a single CWC laminate, the conventional material (7) constrains an opposing CWCV plate (such as shown in FIG. 13a). The designer is not limited to a single CWC laminate or a single CWCV plate but may combine any of the structures shown in 13a, 13a-1, 13a-2, 13b, and 13c to produce a CWCV plate with tailored properties of stiffness and damping in one or multiple directions.

[0204] FIGS. 13f and 13g show the same concepts as FIG. 13d and 13e with one conventional material constraining layer (7) removed. The comments for 13d and 13e apply equally to these figures. It is therefore possible to produce a CWCV plate with tailored properties of stiffness and damping in one or multiple directions.

[0205] FIG. 13h shows a single conventional material (7) constrained on two sides by a CWCV plate. As shown in FIG. 13h the constraining CWC laminates (4 or 5) do not have to be opposing waveforms, but may if the designer chooses. FIG. 13i shows the same basic structure as FIG. 13h only with multiple CWCV plates.

[0206] In summary, it is possible for the designer to combine multiple layers of CWC laminates, viscoelastic materials, and conventional materials in any number of configurations according to the design criteria of the engineer. The examples of FIG. 13 are for illustrative purposes and other combinations will be obvious to one skilled in the art.

CWCV Stiffener Building Blocks

[0207] According to one aspect of the invention, a CWCV plate is bent to form any of the other building blocks all of which are termed “stiffeners”. There are four basic shapes of a stiffener building block including the hat-stiffener, the I-beam, the C-channel, and the Z-channel. The terminology “hat-stiffener” will mean any channel shaped stiffener commonly used on lightweight structures. Generally they are “U” shaped in cross section but they can be any cross sectional shape such as semi-circle, “V” shaped, three sided square, etc.

[0208] The CWCV hat-stiffener is shown as Item 1 in FIG. 14 and is a basic building block for intermediate structural members and larger structures. For example, it can be used in combination with CWCV or conventional material plates to form a beam (for short widths) or part of a panel (for greater widths). The CWCV plate-hat-stiffener combination is an intermediate structural building block for several other larger structures such as panels, beams, curved surfaces, aerodynamic surfaces, rotor blades, propellers, skis, snow boards, any monocoque structure, and many practical structural members.

[0209] As shown in FIG. 14a (perspective view) a generalized hat-stiffened panel would consist of a hat-stiffener (1) shown with a (for example) sinusoidal wave form, (2) a structural laminate or a CWCV laminate (no wave form shown), and (3) a second structural laminate or a CWCV laminate (no wave form shown), or, a special surface treatment or material.

[0210] The composition of the hat-stiffener (FIG. 14a, Item 1) could include any one of the CWCV plates shown in FIG. 13. The laminates of FIG. 14a (2) and (3) could consist of one or more of the following: a) one or more opposing CWCV plates (from FIG. 13), and b) a conventional structural material such as an isotropic metal, a conventional composite laminate, or any other suitable structural material.

[0211] FIGS. 14b through 14e show end views of only a few of the possible combinations of CWCV hat-stiffeners, conventional materials, CWCV plates, and viscoelastic materials (not shown to scale), and are meant to serve as examples for the structure shown in FIG. 14a.

[0212] In FIGS. 14b and 14e the hat-stiffener (1) consists of three laminates and two damping layers (shown shaded). In one embodiment all three laminates would consist of CWC laminates (4) & (5), and would constrain two viscoelastic or anisotropic viscoelastic damping layers (6). Two of the CWC laminates would be of one pattern (4) on the inner and outer surfaces of the hat-stiffener, with an opposing CWC laminate (5) (a laminate having the same basic pattern of (4) but with a 180° phase shift), in the middle. (Figures are not drawn to scale.) An alternative embodiment would have the three laminates consist of one each of a CWC laminate, an opposing CWC laminate, and a conventional laminate or other material, constraining two viscoelastic or anisotropic viscoelastic damping layers (6). The three structural laminates are joined together at the “feet” for good bonding and structural purposes, the damping material being omitted in the region of the feet for this purpose. It is not necessary to configure the damping layers as shown (e.g. in an inverted “U” shape, on top and sides) but the damping layer may be on the top only, on the side only, or eliminated altogether, depending on the requirements of the designer. These examples were given using more than one viscoelastic layer and CWC laminate; of course it is possible to use any number of CWC laminates, viscoelastic layers, or conventional material layers, in any combination, to accomplish the design goals.

[0213] The laminate (2) of FIG. 14a is shown as item (7) in FIG. 14b, could be composed of a conventional composite or other structural material, and would thus represent the main load bearing member in the plate. As shown, the feet of the hat-stiffener are joined directly to the load bearing member (7) promoting strength and good bonding. The laminate (3) of FIG. 14a is shown as Items (4), (5), & (6) in FIG. 14b, and consists of two laminates and two damping layers (shown shaded). In one embodiment both laminates would consist of wavy pattern CWC laminates (4) & (5), and would constrain two viscoelastic or anisotropic viscoelastic damping layers (6). One of the CWC laminates would be of one pattern (4), with an opposing CWC laminate (5). An alternative embodiment would have the two laminates consist of a CWC laminate, and a conventional laminate or other material, constraining two viscoelastic or anisotropic viscoelastic damping layers (6). Only two laminates are shown in FIG. 14b but it is possible to have any number of alternating layers of opposing CWC laminates, viscoelastic or anisotropic viscoelastic damping layers, and conventional composites, according to the design criteria of the engineer.

[0214] The laminate (2) & (3) of FIG. 14a is shown as items (4), (5), & (6) in FIG. 14c and 14d consists of multiple laminates and damping layers (shown shaded). In one embodiment the laminates would consist of multiple wavy pattern CWC laminates (4) & (5), and would constrain multiple viscoelastic or anisotropic viscoelastic damping layers (6). Some of the CWC laminates would be of one pattern (4), with opposing CWC laminates (5). An alternative embodiment would have some of the laminates consist of CWC laminates, with some of conventional laminate or other material, constraining the viscoelastic or anisotropic viscoelastic damping layers (6). It has been determined that the structure of FIG. 14c provides the most efficient and lightweight balanced hat-stiffened panel since it relies on the balanced laminate of FIG. 13b. Instead of a flexible plate as shown in FIG. 13b, the two CWCV plates are split, one becoming a hat-stiffener. It is possible to add an additional plate where the two plates split to form the hat-stiffener, so that the final cross section retains a uniform thickness and laminate structure. The designer is not limited to the use of only two plates. The “plate” makeup may include any of the possible combinations discussed for FIG. 13, according to the design criteria of the engineer. Other combinations will be obvious to one skilled in the art.

[0215] The laminate (2) of FIG. 14a is shown as items (4), (5), & (6) in FIG. 14d, and consists of multiple laminates and damping layers (shown shaded). In one embodiment the laminates would consist of opposing wavy pattern CWC laminates (4) & (5), and would constrain viscoelastic or anisotropic viscoelastic damping layers (6). An alternative embodiment would have the some of the laminates consist of opposing CWC laminates, some conventional laminates or other materials, all constraining the one or more viscoelastic or anisotropic viscoelastic damping layers (6). It is possible to have any number of alternating layers of opposing CWC laminates, viscoelastic or anisotropic viscoelastic damping layers, and conventional composites, according to the design criteria of the engineer. The laminate (3) of FIG. 14a is shown as item (7) in FIG. 14d, could be composed of a conventional composite or other structural material, and would thus represent the main load bearing member in the plate.

[0216] FIG. 14 shows only a few of the design possibilities of the use of CWCV hat-stiffeners, CWCV plates, viscoelastic damping materials, mixed (if desired) with conventional composite or other materials. Other configurations will be obvious to one skilled in the art.

I-beam, C-channel, Z-channel Building Blocks

[0217] The CWCV I-beam stiffener is shown as Item 1 in FIG. 15 and is a basic building block for intermediate structural members and larger structures. For example, it can be used in combination with CWCV or conventional material plates to form a beam (for short widths) or part of a panel (for greater widths). The CWCV plate-I-beam stiffener combination is an intermediate structural building block for several other larger structures.

[0218] As shown in FIG. 15a (perspective view) a CWCV I-beam stiffener (1) would be combined with a structural laminate or a CWCV plate (3) shown with a (for example) sinusoidal wave form, and a second structural laminate or a CWCV plate (2) (no wave form shown), or, a special surface treatment or material.

[0219] The I-beam stiffener (1) could consist of one or more of the following: a) a conventional composite laminate, conventional structural material such as an isotropic metal, or any other suitable material, and/or b) one or more opposing CWC laminates with one or more constrained damping layers of viscoelastic material.

[0220] The flanges (2 &3) could consist of one or more of the following: a) one or more opposing CWC laminates constraining one or more damping layers of viscoelastic material, and/or b) a combination of CWC laminates, viscoelastic or anisotropic viscoelastic damping layers, and conventional composites or other suitable structural material.

[0221] FIGS. 15b through 15f show end views of only a few of the possible combinations of CWCV stiffeners, conventional materials, and CWCV.

[0222] FIG. 15b shows one example of a CWCV I-beam stiffener combined with two CWCV plates (flanges). Any of the CWCV plates shown in FIG. 13 could be combined to form the basic I-beam shown in FIG. 15b.

[0223] FIG. 15c shows one example of a CWCV C-channel stiffener combined with two CWCV plates (flanges). Any of the CWCV plates shown in FIG. 13 could be combined to form the intermediate structure shown in FIG. 15c.

[0224] FIG. 15d shows one example of a CWCV Z-channel stiffener combined with two CWCV plates (flanges). Any of the CWCV plates shown in FIG. 13 could be combined to form the basic intermediate structure shown in FIG. 15d.

[0225] FIG. 15e and 15f amplify FIGS. 15c and 15d respectively to show that the CWCV stiffeners may be formed without viscoelastic materials in the “feet” to promote good bonding and strength.

[0226] As stated above, the examples of FIG. 15 are basic building blocks for damped panels, beams, surfaces, and structural members. FIG. 15 shows only a few of the design combinations in the use of CWC laminates, CWCV plates, viscoelastic damping materials, mixed (if desired) with conventional composite or other materials. Any of the CWCV plates and/or combinations of materials shown in FIG. 13 could be used to make the four basic stiffener building blocks, and any of the exampled intermediate CWCV structures.

CWCV Plate Sandwiched Core Intermediate Structural Member

[0227] As shown in FIG. 16a (perspective view) a CWCV plate sandwiched core intermediate structural member would consist of a core (3), a structural laminate or a CWCV plate (1) shown with a (for example) sinusoidal wave form, and a second structural laminate or a CWCV plate (2) (no wave form shown), or, a special surface treatment or material.

[0228] The sandwiched core (3) could consist of one or more of the following: a) a honeycombed material (3a) b) and/or (3b) a structural foam, special core material for sound proofing, wood, or any other suitable core material(s) and combinations commonly used to provide form to the structure.

[0229] The plate (1 &2) could consist of one or more of the following: a) one or more opposing CWC laminates constraining one or more damping layers of viscoelastic or anisotropic viscoelastic material, and/or b) a combination of CWC laminates, viscoelastic or anisotropic viscoelastic damping layers, and conventional composites or other suitable structural material, or any of the CWCV plates represented in FIG. 13.

[0230] FIGS. 16b &16c show cutaway end views of only a few of the possible combinations of conventional, CWC laminates, and viscoelastic materials (not shown to scale), and are meant to elaborate on the structure shown in FIG. 16a.

[0231] The plate (2) of FIG. 16a is shown as item (7) in FIG. 16b, could be composed of a conventional composite or other structural material, and would thus represent the main load bearing member in the laminate.

[0232] The plate (1) of FIG. 16a is shown as items (4), (5), & (6) in FIG. 16b, and consists of one or more laminates and damping layers (shown shaded). In one embodiment the laminates would consist of opposing wavy patterned CWC laminates (5) & (6), constraining viscoelastic or anisotropic viscoelastic damping layers (4). An alternative embodiment would have some of the laminates consist of CWC laminates, some would consist of conventional laminates or other suitable materials, all having the purpose of constraining one or more viscoelastic or anisotropic viscoelastic damping layers (4). Two CWC laminates are shown in FIG. 16b but it is possible to have any number of alternating layers of opposing CWC laminates, viscoelastic damping layers, conventional composites, anisotropic viscoelastic, or other materials, according to the design criteria of the engineer. As shown, the sandwiched core is joined directly to the load bearing member (7) promoting strength and good bonding. Of course the order of items 4-7 could be reversed where the load bearing laminate (7) was located on the outside of the core surface.

[0233] The laminates (1 &2) of FIG. 16a are shown as items (4-8) in FIG. 16c, and consists of multiple CWC laminates and damping layers (shown shaded). In one embodiment the laminates would consist of multiple wavy pattern CWC laminates (5) & (6), and would constrain multiple viscoelastic or anisotropic viscoelastic damping layers (4). Some of the CWC laminates would be of one pattern (5), with opposing CWC laminates (6). An alternative embodiment would have some of the laminates consist of CWC laminates, with some of conventional laminate or other material, constraining the viscoelastic or anisotropic viscoelastic damping layers (4). The plate sandwiched core could include conventional composites or other materials (Items 7 &8) to provide additional strength. It is also possible to eliminate laminate (7) on the surface of the sandwiched core in FIG. 16c which would bond the viscoelastic material (4) directly to the sandwiched core.

[0234] As stated above, the examples of FIG. 16 are basic building blocks for damped plates, panels beams, surfaces, and structural members. FIG. 16 shows only a few of the design combinations in the use of CWCV plates laminated to various core materials.

CWCV Stiffeners and Sandwiched Core Structures

[0235] FIG. 17 shows one of the many possible uses and combinations of CWCV building blocks (plates and stiffeners) and sandwiched core CWCV structures as discussed for FIGS. 13-16 above, in the design of aerodynamic structures (1 &2). FIGS. 17a and 17c show two such possibilities using a typical airfoil (1 &2) as an example. In FIG. 17a multiple CWCV hat-stiffeners (FIG. 14) are combined with one or more CWCV plates (FIG. 13) and joined together to form the airfoil (1). In FIG. 17c two CWCV plates (FIG. 13) are applied to a sandwiched core (FIG. 16) to form the airfoil (2) and are reinforced by two C-channel CWCV stiffeners (or conventional stiffeners).

[0236] FIG. 17b shows a blown up view of a portion of the hat-stiffened CWCV airfoil of FIG. 17a. FIG. 17b makes use of a CWCV hat-stiffened intermediate structural member illustrated in FIG. 14b. Hollow spaces (10) in the airfoil (1) could be left open for the passage of heated or cooling air, fuel, fluids, or coolant, or could be filled with sound deadening materials, structural foams or other materials depending on the requirements of the design. The above discussion illustrates one example of the use of CWCV basic building block concepts of FIGS. 13-16 used in aerodynamic structures; others will be obvious to one skilled in the art. Such CWCV aerodynamic structures could be used in wings, control surfaces, propeller blades, turbine blades, rotor blades, fan blades, and any other aerodynamic structure where damping, strength, and stiffness are important.

[0237] FIG. 17d shows a blown up view of a portion of the CWCV sandwiched core and C-channel stiffened airfoil of FIG. 17c. FIG. 17d makes use of both the C-channel stiffener building block illustrated in FIG. 15c and the sandwiched core of FIG. 16b. Hollow spaces (10) in the airfoil (2) could be left open for the passage of heated or cooling air, fuel, fluids, or coolant, or could be filled in with sound deadening materials, structural foams or other materials depending on the requirements of the design. Such CWCV aerodynamic structures could be used in wings, control surfaces, propeller blades, turbine blades, rotor blades, fan blades, and any other aerodynamic structure where damping, strength, and stiffness are important.

[0238] As previously discussed, the basic building blocks shown in FIGS. 13 through 16 (and discussed above) can be used in any number of combinations to provide unique damping, strength, stiffness, and acoustic properties. Only two possible designs have been shown; others will be obvious to a person skilled in the art that such combinations would be possible and desirable in certain design situations. Thus it is not necessary to limit the designer to only one family of the many designs shown in FIGS. 13 through 16. For example, using high temperature matrix and damping materials in a fan blade (as shown in FIGS. 17a &4c) would allow the use of CWCV materials in the construction of damped compressor and turbine fans. Cooling air would be passed through the airfoil spaces (48) as is done for conventional metallic fan blades and would control the temperature of the materials. Thus any of the basic designs of FIGS. 13 through 16 could be used in any combination to attain a desired structural characteristic.

CWCV Stiffeners, Plates, and Sandwiched Cores Used in Panels, Floors, Beams & Other Structures

[0239] The use of highly damped materials is beneficial in the building of virtually every structure. In civil structures the use of the CWCV building blocks of FIGS. 13-16 can provide both structural and damping performance not previously attainable. The same can be said for aerospace, automotive, and other structures where damping and structural dynamics are important.

[0240] FIG. 18 shows a few of the many possible uses and combinations of CWCV hat-stiffeners, I-beam stiffeners, and in the construction of larger panels, floors, beams, and structural members. FIGS. 18a through 18e show several such possibilities. There are many ways of making panels or floors from the various CWCV building blocks (e.g. CWCV plates and stiffeners). FIG. 18a shows a typical aircraft floor composed of CWCV I-beams from FIG. 15a coupled to a conventional floor plate or a CWCV plate from FIG. 13. FIG. 18b adds an additional conventional or CWCV plate for added stiffness. FIG. 18c makes use of CWCV plates from FIG. 13 and various combinations of CWCV hat-stiffeners from FIG. 14. Any combination of the CWCV plates (FIG. 13) or stiffener building blocks (FIGS. 14-16) can be used to construct these highly damped panels. The examples in FIG. 18 are shown with a flat shape, but these same combinations can be formed in any number of geometric shapes.

[0241] There are many more possible combinations of CWCV laminates, stiffeners, core materials, etc. that will be obvious to one skilled in the art.

CWCV Building Blocks Used in Skis and Other Sports Equipment

[0242] Skis, snowboards, waterskis and other sports equipment can benefit from the addition of structural materials with inherent damping as represented by the use of CWCV building blocks. For example, downhill racers rely on the dynamics of their skis ability to provide solid contact with the ground and maintain control. Skis that chatter are a hazard. Skis with inherent structural damping are therefore of great value to the sport.

[0243] FIG. 19 shows an example of one of the many possible uses of CWCV structures in the design of skis, snowboards, etc.

[0244] As shown in FIG. 19a (perspective view) a CWCV enhanced ski would consist of a CWCV covered core (1 &4) shown with a (for example) sinusoidal wave form. The core (4) could consist of any of the materials discussed in FIG. 16 above such as honeycomb, foam, wood, etc. The core is strengthened by the addition of a CWCV plate (1) which can consist of any of the examples discussed in FIG. 13, and strengthened by the addition of any of the basic CWCV stiffeners or other intermediate structures as discussed in FIGS. 14-16. Metallic (or other suitable material) edges (2) would be bonded to the CWCV wrapped core (1 &4). Typically a special plastic or other material is bonded to the bottom of the ski (3) to provide protection to the ski and to give the ski special surface properties for better performance. Likewise a protective coating is applied to the top and sides of the ski (5) to provide protection to the core structure.

[0245] FIGS. 19b through 19d show cutaway end views of examples of the use of CWCV plates and other materials in the design and construction of a ski. In general, the combinations of conventional and CWCV plates (FIG. 13), shown in FIGS. 19b-19d mirror the possible combinations discussed in conjunction with FIG. 13. The various combinations of CWC laminates (7 &8) combined with viscoelastic material (6), conventional laminates or isotropic materials (9) and special protective surface materials (3) can be arrayed as shown depending upon the dynamic properties desired.

[0246] Two specific examples of skis that have been built using CWCV plates and conventional materials are shown in FIGS. 20 and 21. The ski discussed in FIG. 19 is shown in FIG. 20 assembled (FIG. 20a) and in exploded view in FIG. 20b. In FIG. 20 conventional laminates “packs” (6) were replaced by combinations of unidirectional carbon composite (7) viscoelastic layers (8) and opposing CWC laminates (9 &10). Torsional rigidity was provided by the ±45° bi-directional composite cloth. The combination is laminated on to the core (4) and enveloped by protective coatings (3 &5) and cured in the standard manner.

[0247] An alternative embodiment of the ski shown in FIG. 20 is represented in FIG. 21 shown assembled (FIG. 21a) and in exploded view in FIG. 21b. As shown in FIG. 21 the basic structure discussed for FIG. 20 applies in this figure as well, except that the alternating layers of viscoelastic (8) and CWC laminates (9 &10) are wrapped around the bi-directional cloth-covered core (4). The scaling shown in FIGS. 19-21 are exemplary of a few of the many assembly methods available to the designer. By varying the amounts of conventional composites (7 &11) and CWCV plates (8-10) it is possible to “tune” the dynamics of the ski.

[0248] There are many other combinations of viscoelastic or anisotropic viscoelastic materials, and conventional composites, special coatings, or other materials which can be used to design and build the ski, and will be obvious to one skilled in the art.

[0249] For example, in the case of the water ski, it may be desirable to eliminate the metallic edges (2) and the special covering for the bottom (3) or the top & sides (5). In this case, the CWC laminates on the surface would provide the aesthetic covering as well as the damping and structural properties of the ski.

[0250] The example CWCV ski structures discussed above could be used for snow skis, snow boards, surf boards, slalom skis, beams, boards, and many sports equipment or structural components where damping, strength, and stiffness are important. CWCV Tubes.

[0251] A CWCV tube can be made from the basic CWCV plate building block discussed in FIG. 13. Although the basic structure shown in FIG. 22e was contemplated by Dolgin, the use of stepped CWCV plates as shown in FIGS. 22f and 22g was not. Neither was the use of the non-sinusoidal wave forms of FIGS. 1-5. The use of the concepts in FIGS. 1-5 and 13 in the design and the manufacture of tubular structures can provide damping and reinforcement to diverse structural components such as concrete pillars, pilings, beams, and foam or other cored structures. For example, the use of CWC bi-directional cloth where the fill fibers are straight and the wavy fibers are oriented as in FIG. 22a will provide containment, damping, and structural reinforcement for a concrete beam or column. The use of CWCV structural reinforcement and damping will provide additional safety margin, survivability, and increased service life to a concrete structure. It is well-known that the use of composite materials as a surface treatment for standard concrete structures is highly desirable and becoming more common. None of the current methods, however, add inherent damping to the structure.

[0252] The CWCV tubes shown in FIGS. 22b through 22g can be used in the manufacture and improved dynamics of sports equipment as diverse as golf club shafts, arrow shafts, tennis rackets and similar devices, baseball bats and similar devices, poles, shafts (such as helicopter and automotive drive shafts), antennae components, bicycle components and frames and fishing rods.

[0253] The tubular examples of FIG. 22 are shown with a round cross section but any cross section can be used including elliptical, square, rectangular, polygonal, aerodynamic, or even a special irregular shape or combination of shapes designed to optimize structural parameters. The tubular examples of FIG. 22 are also shown of constant and uniform cross section throughout the length of the tube. Of course it is possible to taper the tube, bend the tube in any reasonable shape, or even create an irregular taper and shape along its length depending on the application. It is a common practice to construct a tube on a straight mandrel (for example) remove it prior to curing, place it in a curved mold, and form curved tubes of constant or variable cross section and shape. Such a process would be used in the manufacture of a CWCV damped tennis racket (for example). Of course any of the material combinations discussed in conjunction with FIGS. 1-5, 13-16, could be used in the manufacture of a CWCV tube.

[0254] A single layer of wavy composite has a fiber lay that oscillates between a negative maximum angle and a positive maximum angle in a pre-determined pattern. As a result, the individual laminae will vary in stiffness and displacement characteristics along its length as the angle of the fiber changes. Thus where the angle is 0° relative to the length of the waveform, the laminae will have the characteristics of a 0° unidirectional composite, and where the angle diverges from 0° the laminae will have the characteristics of an off-axis unidirectional laminae. If several opposing wavy composite laminae are joined together in a symmetric lay-up (see FIG. 23), the laminate will exhibit quasi-isotropic properties at any point along the length.

[0255] Refer to FIG. 25. Items 5 and 6 refer to opposing pairs of wavy composite laminae. Where the angle is at a ± maximum (item 10), the properties of the laminate will be like a ± unidirectional crossply. These areas where the angles are at a ± maximum will resist in-plane shear loads effectively but will have a lower longitudinal or lengthwise stiffness. Where the angle is at 0° (item 11) the laminate will have the properties of a 0° unidirectional lay-up (Pratt 1999). These areas (where the angle of the fibers is 0° relative to the longitudinal direction) will not resist shear loads effectively but will have a greater lengthwise stiffness. These localized differences in stiffness can be overcome by combining two pairs of wavy composite laminae into a single laminate as is shown for item 7. The structure of the wavy laminate enclosed by item 7 is hereafter termed “wavy crossply laminate.”

[0256] Thus, for one pair of opposing wavy laminae, the angle will be at a ± maximum but the second pair of opposing wavy laminae will have a fiber angle that is at 0° or nearly 0° relative to the general direction of the laminate. This gives the laminate an equivalent unidirectional lay-up of four total layers where two of the layers are unidirectional plies with a ± fiber orientation, and the other two layers were equivalent to two 0° unidirectional laminae. The difference is that the construction of a unidirectional version of a crossply laminate cannot be easily automated; the construction of a wavy crossply laminate can be automated. In the process of characterizing the properties of damped wavy composites, several sample tubes constructed from wavy composite with constrained viscoelastic layers were compared to equivalent undamped unidirectional crossply tubes. It was found that damped wavy tubes took significantly less time to fabricate. As a result, and in an effort to save labor time, several undamped tubes were manufactured using the lay-up shown in FIG. 25, item 5 (one pair) as a replacement for the undamped unidirectional tubes because of the ease with which wavy tubes could be fabricated. The realization of the superior handling, excellent stiffness and strength, and significant time savings led to additional discoveries which are the subject of the present invention.

[0257] The following discussion further amplifies the advantages of using wavy composite pre-preg in wavy crossply lay-ups. FIG. 26 illustrates three typical crossply lay-ups that use several unidirectional pre-preg plies (item 2) to build a laminate with quasi-isotropic properties. In reference 10, Rienfelder, et al showed how to construct a rotary wing spar using different materials and ply stacking methods and cited superiority of consolidation of the laminate, uniformity, and tailorability of the laminate combinations as advantages. They further cite the disadvantages of fiber winding techniques for this application as “relate[d] to difficulties associated with expanding/urging the fibers against the mold surfaces of the matched metal mold.” It can be concluded that in some applications, fiber plies or laminae made from unidirectional materials cut off-axis will be preferable to the use of fiber winding methods and that continuity of fibers of such plies will be interrupted. The authors state that such plies were butt-joined together and that such joints from additional plies above and below in the stacking sequence were offset so that adjacent butt-joints would not coincide.

[0258] This concept is shown in general in FIGS. 5 and 6. Pre-preg made with unidirectional fibers comes in finite widths, typically up to 1.5 meters in width, in very long lengths. The same is true with cloth pre-preg, and wavy composites. Because of the limited widths of pre-preg, there is a finite length of off-axis material that can be cut from a roll of unidirectional pre-preg. In FIG. 27, several unidirectional plies (12) are cut from a long continuous sheet of unidirectional material. The plies are then buttjoined (13) and overlapped (14) with other plies from the same cut of material. The weakest link in the laminate is the seam between butt-joined plies (13) where fiber continuity is interrupted. Thus to obtain a viably strong laminate with an off axis orientation, a minimum of two laminae are required.

[0259] Wavy composites do not have this limitation. As shown in FIG. 27, two or more plies (1) of wavy pre-preg can be placed adjacent to each other to create a wider laminae (15). When using concepts shown in FIG. 25, the wider wavy laminae can be combined in different ways to form a laminate with the desired properties. To further amplify the advantages of wavy composite, refer to FIGS. 3 thru 6.

[0260] In order to make a crossply laminate from unidirectional pre-preg similar to concepts shown in FIG. 26 with a ply stacking sequence of 0°/+45°/−45°, it would be necessary to cut the off-axis plies as shown in FIG. 27 item 12. Several such plies would be butt-joined and overlapped as shown in FIG. 28 items 13 and 14. While the 0° ply (item 16) is continuous in this drawing, there are significant interruptions of fiber continuity in the off-axis plies. All of this is typically done by hand and is very labor intensive.

[0261] If, however, the designer were to use wavy composite, the equivalent of the 0°/+45°/−45° laminate could be completed using wavy plies offset as shown in FIG. 25 item 7. If hand labor is used, the steps required to accomplish the desired laminate are greatly reduced. Instead of having to cut separate laminates as shown in FIG. 27, item 12, the fabricator uses successive wavy layers of any desired length to form the wavy crossply laminate. In fact, it is very possible for this process to be automated by feeding (for example) four spools of wavy composite through a pair of pinch rollers with the patterns offset appropriately, to create a continuous roll of wavy crossply as shown in FIG. 25, item 7. The beginnings of such a process are shown in FIG. 28 (bottom) where the second wavy composite layer (1) is overlaid on the first layer (15). FIG. 28 shows the next layer of wavy composite (1) offset to the right of the base layer (15) for clarity. In actual practice both layers (1 and 15) could begin at the end; this figure is only illustrative of the concept. Of course there are many methods and mechanism whereby wavy layers can be combined to form wavy crossply laminates including successive passes by a single axis laminator, multiple feed rolls, etc., and even manual labor methods. All will be significantly easier and more economical than current methods of producing unidirectional pre-preg based crossply laminates.

[0262] The present invention includes a structure such as is shown in FIG. 23 where several layers of wavy composite (1 and 3) are used to build a “balanced” wavy composite laminate.

[0263] The present invention also includes a laminate consisting of a mix of wavy composite layer(s) (items 1 and/or 3) and unidirectional layers (2) as shown in FIG. 24. In this figure the laminate consist of two opposing wavy layers (1 and 3) and one transverse unidirectional ply (2). This is a very lightweight, efficient lay-up that has been used to produce undamped tubes with excellent stiffness and improved strength properties. It has been found, that the lamination of at least one transverse ply (2) and at least one wavy ply (1 or 3) provides greater strength. When a single layer of wavy composite is pulled to failure (along the strong or longitudinal axis), the failure generally occurs in the matrix where the angle of the fiber is at a ± maximum. The matrix splits between the fibers. If fibers are added generally perpendicular to the wavy fiber lay, then the laminate failure occurs at a much high stress level because the transverse fibers resist the transverse stresses efficiently. It is also possible to orient two or more wavy layers transversely to each other as is shown in FIG. 25 item 4. Such a laminate structure would be useful in providing quasi-isotropic properties to sculpted surfaces where special properties or laminating issues are important.

[0264] The most useful configuration is shown as items 5-9 in FIG. 25. Items 5, 6, and 8 represent pairs of opposing wavy composite laminae joined together. The two (or more) wavy laminates need not “oppose ” each other (e.g. have a one-half waveform phase lag or offset) to conform to the meaning of the present invention. It may be useful to cause a more or less than half waveform phase lag as demonstrated in the area enclosed by item 7 of FIG. 25.

[0265] Combining two or more “pairs” of wavy laminae need not be joined together along their longitudinal axes but may be laid at some off-axis angle with respect to each other as is shown in FIG. 25, items 5 and 8. This will give a unique crossply effect as shown in the area enclosed by item 9. Although the pairs of wavy laminates (FIG. 25, items 5 and 8) are shown essentially perpendicular to each other, it is also possible to vary this angle more or less to accomplish unique laminate properties. For example, it may be desirable to place the pairs of wavy laminates at a ±30° angle or some other angle with respect to a reference line as is commonly done with unidirectional plies. These different angular orientations are contemplated by this invention.

[0266] To further illustrate the capability of wavy crossply laminates, the following table documents the equivalent axial stiffness of several different configurations of wavy crossply laminates using (for example) a typical carbon fiber-resin combination to represent the material properties of both unidirectional and wavy composite. Table 1 shows the configuration of each laminate. Each laminate is defined by the words “unidirectional”, or “wavy crossply”, or “wavy crossply & unidirectional” defining the materials used in the lay-up. This is shown in the “Laminate” column of the table. The laminate configuration is further defined by the angle of the plies relative to the longitudinal direction of the sample tube used to model the lay-up. This is shown in the “Configuration” column of the table. For example, “0°” means all fibers are oriented at zero degrees to the reference, or run longitudinally in the tube. The relative axial stiffness of the laminate is given in the column labeled “Axial modulus.” This represents the smeared axial material properties of the lay-up. Axial modulus represents the relative ability of the laminate to resist tension or compression loads, and even bending loads if the neutral axis shear forces are ignored. The “Shear modulus” column represents the ability of the laminate to resist torsion or shear loads. 1

[0267] Laminate 1 is a unidirectional fiber composite lay-up that shows the 0 degree properties of the fiber reinforce composite used to model all subsequent lay-ups. Laminate 2 shows the properties of a conventional ±30 degree unidirectional composite crossply lay-up. Note that the equivalent axial modulus of laminate two is considerably reduced from that of laminate 1, but the equivalent shear modulus is greatly improved over the shear modulus of laminate 1. This is a classic example of how crossply composites lose axial modulus rapidly as the angle of the fiber diverges from zero degrees, but their ability to resist shear loads improves.

[0268] As discussed above and shown in FIG. 28, a unidirectional crossply laminate is difficult to fabricate with automated means. However, as shown in Table 1 (laminate #2), crossply laminates are useful in providing resistance to both axial and shear loads. If more axial stiffness is required, a unidirectional 0 degree ply can be added. The results of this combination are shown as laminate #3 in Table 1. The axial modulus is improved by 64% relative to laminate #2 but the shear modulus is reduced 26%.

[0269] Wavy composite can be used to create wavy crossply laminates equivalent to the unidirectional crossply laminates discussed above. Wavy crossply laminate #5 is equivalent in both axial and shear modulus to unidirectional crossply laminate #2. Likewise, wavy crossply laminate #7 is equivalent in both axial and shear modulus to unidirectional crossply laminate #3. Both wavy crossply laminates are significantly easier to fabricate, do not cut fibers (and therefore do not show any seam), and can be readily automated. The same cannot be said for the two unidirectional crossply laminates.

[0270] The remaining entries of Table 1 example only a few of the many different combinations possible by using wavy composite materials. For example, wavy crossply laminate #4 represents the axial and shear modulus of one pair of opposing wavy laminae (FIG. 25, item 5 or 6). This combination has a 60% greater axial modulus than the ±30 degree unidirectional crossply lay-up (laminate #2) but a 57% lower shear modulus. It is exampled here because it represents the simplest wavy crossply laminate. Obviously, it is possible to modify the characteristics of the laminate by changing the waveform, offset, or by orienting the wavy laminae off-axis. This example represents only one combination of parameters and their effects on the stiffness of the laminate thus created.

[0271] If greater transverse strength was desired in the crossply laminate, the designer would add an additional layer of unidirectional composite. This is shown in laminates #6 which is a modified version of #4, and in laminate #8 which is a modified version of laminate #7. Both can still be readily automated in fabrication since the 90 degree layers could be added easily. Additionally, 0 degree unidirectional layers can be added to augment the axial modulus without unduly sacrificing the shear modulus. This is shown as laminate #9 in Table 1 and compares favorably with laminates 3, 7, and 8.

[0272] The present invention does not limit the waveforms used to identical wave patterns, periods, to a particular waveform (such as a sine wave, cosine wave, etc.), a particular orientation, or to a particular offset. The properties desired in the laminate may require a non-periodic waveform or a combination of waveforms of any type, and unidirectional or woven cloth laminae. The selection of waveforms, materials, orientations, or offsets to use will depend on the properties desired in the laminate. The selection will be obvious to one skilled in the art. The wavy laminates discussed here and illustrated in the figures are for example purposes only.

[0273] Finally, the range of possible uses of the example wavy crossply lay-ups shown in Table 1, is potentially limitless. In reference 12, a construction for a rotary wing spar is revealed which uses unidirectional and woven fiber composite layers to provide efficient axial, bending, and torsional stiffness. Although the examples of Table 1 were based upon the analysis of a sample tube, the same or similar wavy composite lay-ups could be used to construct an equivalent spar at a greatly reduced costs. Other applications include automotive, aerospace, and marine drive shafts, composite wing structures of all types, panels, composite I-beams, channels, and virtually an endless combination of possibilities. Composite arrow shafts and golf club shafts would likewise benefit from greatly reduced labor costs in construction. Other applications will be obvious to those skilled in the art.

[0274] By combining the concepts shown in references 1, 15, 5, and 6, it is possible to create a lightweight, damped, golf club shaft that improves “feel”, dramatically reduces free vibrations, widens the “sweet” spot on the club head, and reduces shock to the user's anatomy.

[0275] Refer to FIG. 25. In the preferred embodiment, major stiffness in axial, bending, and torsion in the golf club shaft (or other tubular structures) is provided by two pairs (or more) of opposing and offset wavy composite laminae as shown in FIG. 25, item 7. Items 5 and 6 refer to opposing pairs of wavy composite laminae. Where the angle is at a ± maximum (item 10), the properties of the laminate will have the properties of a ± unidirectional crossply. These areas where the angles are at a ± maximum will resist in-plane shear loads effectively but will have a lower longitudinal or lengthwise stiffness. Where the angle is at 0° (item 11) the laminate will have the properties of a 0° unidirectional lay-up (Pratt, reference 15). These areas (where the angle of the fibers is 0° relative to the longitudinal direction) will not resist shear loads effectively but will have a greater lengthwise stiffness. These localized differences in stiffness can be overcome by combining two pairs of wavy composite laminae into a single laminate as is shown for item 7, termed “wavy crossply laminate.”

[0276] Thus, for one pair of opposing wavy laminae, the angle will be at a ± maximum but the second pair of opposing wavy laminae will have a fiber angle that is at 0° or nearly 0° relative to the general direction of the laminate. This gives the laminate an equivalent unidirectional lay-up of four total layers where two of the layers are unidirectional plies with a ± fiber orientation, and the other two layers were equivalent to two 0° unidirectional laminae.

[0277] If this wavy crossply structure is combined with one or more viscoelastic layers and one or more constraining wavy composite layer, the result is a lightweight golf club shaft with high damping and excellent bending and torsional stiffness. Additionally, the wavy fiber composite has an aesthetically pleasing look which in good daylight seems to shimmer and sparkle. Golf club shafts can be constructed entirely from wavy composite and viscoelastic damping materials. The primary bending and torsional load resistance is provided by a wavy crossply structure; damping is provided by two viscoelastic layers and two double ply wavy composite constraining layers, as shown in part in FIG. 1. The overall construction of the golf club shaft is shown in FIG. 32.

[0278] As seen in FIG. 32b, the wavy fiber lay runs the length of the golf shaft that is preferably tapered. The generalized laminate structure is shown in cross section in FIG. 32a where Item 1 represents one layer of wavy composite of one pattern, Item 3 is an opposing wavy layer, Item 2 is the viscoelastic damping layer(s), and Item 4 is the main load bearing part of the shaft. Item 4 is preferably made from four or more wavy layers arranged in a wavy crossply scheme (FIG. 25, Item 7). It is also possible to construct the load bearing portion of the shaft (Item 4) from conventional unidirectional laminates or isotropic materials. At the handle end (Item 5), the two layers, Items 1 and 3 are bonded together by removal of the viscoelastic layers (Items 2) to provide additional load coupling to the load bearing layer (Item 4). At the tip end (Item 7), the viscoelastic damping layers (Item 2) are removed to provide both good load coupling to the load bearing layer (Item 4), and to provide an area where the length of the club can be tailored to the desires of the owner. These methods of removing the viscoelastic from between the wavy layers or wavy layer and load bearing structure are generally termed “welds”. Additionally, in these “weld” areas, the viscoelastic can be replaced with wavy, unidirectional, or cloth composite to provide additional strength and load resistance.

[0279] Other methods of construction of the damped wavy golf club shaft are possible including but not limited to progressively welding the various viscoelastic layers, rearranging the order of layers, or adding or subtracting additional layers of viscoelastic, wavy constraining layers, or load bearing layers, as shown in FIG. 22 and discussed in Reference 1. The characteristics of the structure can be modified by interposing unidirectional or multidirectional materials in the load bearing layers as shown in FIG. 24, and discussed in Reference 15. Damping and stiffness characteristics can be modified by the addition of unidirectional or bi-directional materials in the structure of the constraining layers as shown in FIGS. 4 and 5. The minimum structure for a golf club shaft dampened with a wavy composite layer is a shaft, such as a steel or composite shaft, with at least one viscoelastic layer affixed to the surface of the shaft (on the inside or outside) wherein the viscoelastic layer is constrained by at least one sinuous wavy composite layer attached to the viscoelastic layer on the side of the viscoelastic layer that is opposite to the side of the viscoelastic layer adjacent to the shaft.

[0280] The structure shown in FIG. 30 is useful in that the transverse fibers strengthen the wavy composite against premature failure. Failure occurs in the wavy layers generally when the loads applied to the structure exceed the rupture strength of the matrix where the angle of the wave is at a ± maximum. By adding additional layer(s) of transverse fibers this type of failure can be avoided while preserving the damping characteristics of the wavy composite structure.

[0281] If greater damping, stiffness, or strength is desired, it is possible to place intermediate “welds” by removing viscoelastic material from key areas of the laminate as shown in FIG. 31, Item 5. Removing viscoelastic material from these areas shortens the effective length of the damping area and allows better coupling of the dynamic loads along the length of the structure.

[0282] The structure of the golf club shaft shown in FIG. 32 resulted in a capable and lightweight shaft that provides less club head “flutter”, a wider “sweet spot”, greatly reduced vibration, and reduced shock transmission to the user. The wider “sweet spot” is due to the reduction of lateral and torsional vibration magnitudes of the head during contact with the ball. Typically the “sweet spot” on a club head is the approximate size of a quarter. Contact in this area of the club head with the ball, results in a greater transference of energy to the ball on a conventional golf club. Striking the ball outside of the “sweet spot” results in significant loss of energy transference on a conventional club, and greater shock to the user. The prototype club made from a shaft as shown in FIG. 32 had no discernable limits to the “sweet spot”. Thus, the construction of a golf club with this improved shaft results in greater consistency, energy transference, with a resultant increase in range, and accuracy. The reduction in shock transference to the user is another benefit of this shaft structure. In conventional shafts, this ringing of the golf club after impact induces sympathetic ringing in the hands and arms of the user and can cause damage in the long term, similar to “tennis elbow” and other repetitive type injuries. A golfer who anticipates the “sting” of the swing will be reluctant to hit the ball normally and will have a tendency to “pull” the swing, with subsequent reduction in range, and loss of accuracy and consistency.

[0283] The structure of the golf club shaft can easily be extended to the production of baseball bats and similar devices where, for example, the overwrapping of the handle and part of or all of the barrel would provide both additional strength and resistance to splitting (for wooden bats). Additionally, the dramatic reduction in resonance amplitudes and duration after impact will reduce or eliminate the “sting” often associated with off-sweet spot hits. For metal bats or bats made from composite, this wavy composite damping concept can be added to the interior of the bat during construction or exterior during retrofitting. In this case, experience has shown that the reduction of vibrations and sting is likewise very apparent.

[0284] The preferred configuration for a wooden bat is to wrap the handle from about one inch from the butt end to a point approximately 18 inches from the butt end. The first four layers of wavy composite would be two pairs of opposing wavy composite with one pair offset from the other pair by a quarter wavelength as shown in FIG. 25 item 7. If damping was not desired and only reinforcement of the bat handle was desired, the four layers of wavy composite would provide the necessary reinforcement to prevent the handle from breaking. If damping is desired, wavy damping layers would then be added using opposing pairs of wavy composite combined with viscoelastic as shown in FIG. 32 and discussed for the golf club. Only one damping layer would be required but damping would be half of that of a pair of opposing wavy damping layers.

[0285] The preferred configuration for a hollow metal bat would be to affix the wavy composite damping and reinforcement layers to the inside of the bat by wrapping an expanding mandrel with wavy composite layers and viscoelastic in as many single or opposing pairs as desired, insert the mandrel into the barrel end of the bat, expand the mandrel, and cure the wavy composite-viscoelastic damping layers inside the metal bat. This preferably would happen in the first 18 inches of the handle (from the butt end) since this is the area where most of the vibrations that “sting” a batter occur. If reinforcement is desired, crossply wavy layers could be added to the damping layers and the mandrel inserted as previously discussed. In this manner, the reinforcing layers of wavy crossply material would be next to the metal on the inside of the bat, and the damping layers towards the interior of the hollow bat. For retrofits to existing metal bats, the handles could be wrapped as was discussed for the wooden bats.

[0286] The structure of the golf club shaft can easily be extended to the production of fishing rods by simple scaling. The benefits would be the reduction of tip resonance and magnitude of vibration which causes the lure to have an unnatural movement.

[0287] This structure can be applied to the production of highly damped gun barrels where Item 4 of FIG. 32 would include a metallic liner for the rifling and wear resistance to the travel of the projectile through the tube. The obvious benefit is the reduction of “barrel slap” where the barrel vibrates as the projectile travels the length of the tube. This is a major source of projectile dispersion in large gun tubes. These benefits will also be evident in the use of these damping concepts on rifles. Likewise the use of these methods in the production of arrow shafts would result in greater accuracy and consistency.

[0288] While the structure of the golf shaft shown in FIG. 32 is tapered, there are many more applications where the cross section may be held constant or varied by some other criteria. The production of drive shafts of all kinds can benefit from this method of construction. By using the methods and concepts discussed above and shown in FIGS. 1-7, it is possible to construct drive shafts for helicopters, automobiles, marine applications, and other high speed turning operations where resistance to torsional, bending, and the “super critical” modes are needed. The reduction of torsional vibration magnitudes reduces both the magnitude of stresses and strains experienced by the shaft, and reduces impact loading on gear boxes that may be attached. Prevention of the “super critical” mode of vibration where the bending frequency of the shaft matches the rotational speed of the shaft is the most pressing need in (for example) helicopter drive shafts. Both damping and stiffness are critical to prevention of catastrophic failure of the shaft in this mode. Avoidance of these failure modes is provided by the unique characteristics of the construction methods and concepts discussed above. Only the numbers of damping and constraining layers, and which material combinations are used will vary depending on the individual application and the expected loads.

[0289] These methods can be used to construct highly damped and capable boring bars for machining of deep cavities on lathes. Other machine tool components that would benefit from these methods include spindle extensions where resistance to both bending and torsional loading and reduction of resonance magnitudes is important to the prevention of chatter.

[0290] Likewise the use of these methods can easily be adapted to the production of oil drilling pipe where the damping and stiffness offered by the design shown in FIG. 32 would prevent the “pogo effect”, and torsional chattering of the cutting head. In this application, both axial, bending, and torsional chatter can be prevented by this construction method, and drill pipe breakage or damage to the cutting head, in the hole can be avoided.

[0291] The production of larger versions of the concept shown in FIGS. 1-7 can be used to provide containment to reinforce concrete pillars, columns, and beams use in the construction of bridges, buildings, peers, pilings, and other civil structures. In addition to providing containment to the concrete, the damped wavy structure provides protection from the elements (especially salt and water corrosion of rebar), and most importantly, provides additional strength, stiffness and inherent damping to the structure. This would result in structures that would last for 75 years or more, provide survivability of the structure during earthquakes, and provide increased occupant comfort from natural sway and vibration in tall structures.

[0292] The concepts illustrated in the figures and discussed above need not rely solely on the use of waveforms that are oriented with the major axis of the tube or structure. Additionally, it is possible, with allowance for the differences in diameter of the laminate and a corresponding requirement to change the wavelength of the pattern, to place one or more of the waves off-axis to the length of the mandrel, or tube. In this case careful planning and alignment of the waveforms is required to provide for matching of the opposing waveforms necessary for efficient damping performance. The waveform required for any particular layer will be a function of the effective diameter of the laminate in the structure, the previous waveform, and the off-axis angle of the laminate. This insures that the opposing waveforms in successive layers oppose each other properly throughout the thickness of the structure where the diameter and thus effective length of the off-axis orientation increases in proportion to the diameter of the laminate. The major advantage of an off-axis orientation of the wavy damping layers would be the increased efficiency, stiffness, and damping properties of the laminate for torsional loads.

[0293] The concepts illustrated in the figures and discussed above need not rely solely on the use of waveforms that are sinusoidal but may make use of any sinuous waveform that taylors the damping and stiffness of structure. As long as the minimum diameter of the curvature of the wavy composite is not excessive which would have a tendency to promote fiber breakage, the waveform may appear to have any useful sinuous shape. Additionally, all these designs contemplate the use of bi-directional composite cloth that has had the warp sinuously shaped, with the fill fibers of the same fiber type or of a different type in various percentages of fill. The advantage of fill fibers in the wavy composite pre-preg is that it prevents premature failure of the laminate at the areas of maximum fiber angle.

[0294] Other applications will be obvious to those skilled in the art.