Abstract:
A material suitable to keep layers or plies of a composite material from adhering to each other during production and transportion.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to, and is a Divisional of, U.S. patent application Ser. No. 12/870,580, filed on Aug. 27, 2010, now allowed, which claims priority from U.S. Provisional Application No. 61/275,397, filed on Aug. 28, 2009, both of which are hereby incorporated by reference in their entirety. 
     
    
     FIELD OF INVENTION 
       [0002]    The subject invention relates to the art of composite materials, and more particularly, to 3-Dimention fiber structure for composite and interfaces. 
       BACKGROUND OF THE INVENTION 
       [0003]    Fiber composite materials have been used in a wide range of industries (e.g., aerospace, aviation, automobile, ship, construction, sports equipment, etc.) for several decades. Fiber composite materials are generally manufactured through a process where fiber products are laid up filaments by filament, ply by ply, and layer by layer, then bonded together using materials, such as plastics, rubber, metal, or other non-metal materials. A connection interface exists between two filaments/plies/layers. Fiber composite materials are usually weak at connection interfaces or inter-laminate area. For example, tensile strength of fibers within a ply can be higher than 3000 MPa (Mega Pascal), much higher than that of common steel; but interface or inter-laminate strength of fiber composite material is usually about 100 MPa, even lower than that of aluminum. Thus, the interface or inter-laminate strength of fiber composite material is only about 1/30 of the tensile strength of fiber themselves. 
         [0004]    It is generally difficult and expensive to increase the interface or inter-laminate strength of the fiber composite material by using a stronger bonding material (e.g., adhesives, plastics, or resin, etc.). The lower interface or inter-laminate interface strength of composites often leads to structural failures, such as de-lamination and de-bonding under conditions such as stress, impact, or fatigue. Therefore, adoption of fiber composite materials, especially in load-bearing structures, has been limited by their susceptibility to out-of-plane failures caused by low interface or inter-laminate strength. To alleviate these problems, methods of trans-laminate and cross-interface reinforcements, such as 3-D stitching, 3-D weaving, 3-D knitting, or 3-D braiding, have been used to improve de-lamination resistance and enhance interface strength. These 3-D reinforcement techniques, however, demand sophisticated equipments and require complicated manufacturing processes, and therefore, prolong the manufacture process, drive up the manufacture cost, and lower the manufacture productivity. 
       SUMMARY OF THE INVENTION 
       [0005]    In general, in an aspect, the invention provides a sheet article, the sheet article including a substrate, a plurality of fasteners on at least a portion of one surface of the substrate, and a cover, at least partially covering the plurality of fasteners, wherein the cover at least partially protects the plurality of fasteners and prevents the plurality of fasteners from engaging other fasteners or pressing down and wherein the covered fasteners can be exposed and the cover can be removed if needed. 
         [0006]    Implementations of the invention may provide one or more of the following features. The plurality of fasteners are selected from a group comprising of hooks, loops, anchor-shape hooks, fish hooks, forks, big heads, arrow-shape hooks, group loops, and group hooks. The cover includes a second substrate, a plurality of upstanding or protruding studs or walls on the second substrate, wherein the plurality of upstanding or protruding studs or walls protect a plurality of fasteners on an adjacent sheet. The hook or loop shape hook is stiffened to a certain level so that it can engage with other hook or loop fasteners on other sheet articles. In order to stack up the sheet articles, the covers are only on the designed parts of the designed sheet (e.g., a designed part on the surface sheet), laid up at least three plies of the sheet articles to form a 3D composite, wherein all plies may be fastened by the engaged fasteners on the piles, wherein matrix material is used to bond the at least three plies, wherein surface side may or may not have fasteners, wherein surface side may or may not have covers at the designed part. The sheet article is impregnated with one or more matrix materials selected from the group of polymer, resin, metal, ceramic, carbon, or glass to obtain a prepreg sheet, laid up at least two said prepreg plies to get a 3D composite, wherein only surface side may or may not have covers at the designed part. 
         [0007]    Implementations of the invention may also provide one or more of the following features. In order to increase the bonding strength of two articles, the cover is removed; insert the sheet article to the interface area of two articles when bonding the two articles, wherein the fasteners on the sheet article will extend into the bodies of two bonding articles to increase interface strength, wherein the fasteners on the sheet article will interlock with the fasteners of two bonding articles if they have fasteners themselves. The substrate is made of plurality of fiber sheet plied contiguously, wherein the plurality fiber sheet are mechanically fastened together. The fibers in the same sheet can be lined up at the same direction or at different directions forming a multi-layer, multi-axis sheet. In order to stack up the sheet articles, the covers are only on the designed parts of the designed sheet (e.g., a designed part on the surface sheet), laid up at least two plies of the sheet articles to form a 3D composite, wherein all plies may be connected and supported by the fasteners on said piles, wherein matrix material infiltrates at least partial of the plies and fasteners, wherein said plies are not fully touched and there are hollow spaces between plies, wherein surface side may or may not have fasteners, wherein surface side may or may not have covers at the designed part. The sheet articles have gap between two sheet articles to fit pins of fiber sheet handling tool, wherein pins can grab and separate the sheet article. The fasteners can lean with acute angle at desired location and direction. The substrates have matrix material at inner walls of openings, wherein fasteners can be aligned through openings. 
         [0008]    In general, in another aspect, the invention provides a method of using fastener cover on a sheet, including the steps of applying a covering material to at least one fastener on the sheet to protect the at least one fastener and removing the cover material during a bonding process to expose the at least one fastener. 
         [0009]    Implementations of the invention may provide one or more of the following features. The method further includes the step of applying a sizing or a coating material to coat the at least one fastener. 
         [0010]    In general, in yet another aspect, the invention provides a tool for handling a sheet with fasteners, including a base, a connector, capable of being coupled to a driving force, a housing unit in the base, a moving element, positioned at least partially within the housing unit and coupled to the driving force, and a plurality of fasteners on at least a portion of one surface of the moving element. 
         [0011]    Implementations of the invention may provide one or more of the following features. The moving element can be fully hidden in the housing unit in the base and can extend out of the housing unit. A plurality of fasteners exist on at least a portion of one surface of the base if they are not on the moving element. 
         [0012]    In general, in still another aspect, the invention provides a tire or cutting wheel, including a plurality of sheets and a plurality of fasteners on at least one of the plurality of sheets, wherein the plurality of fasteners on adjacent sheets are interlocked. 
         [0013]    Implementations of the invention may provide one or more of the following features. The plurality of fasteners in the cutting wheel withhold particles against wearing during cutting. 
         [0014]    These and other capabilities of the invention, along with the invention itself, will be more fully understood after a review of the following figures, detailed description, and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0015]      FIG. 1  illustrates an exemplary sheet of fibers or substrate with fasteners on its both sides. 
           [0016]      FIG. 2  illustrates an exemplary composite made of fiber sheets with fasteners. 
           [0017]      FIG. 3  illustrates an exemplary 3-D prepreg sheet with fasteners on its both sides. 
           [0018]      FIG. 4  shows a cross-section view of the 3-D prepreg sheet of  FIG. 3 . 
           [0019]      FIG. 5  illustrates an exemplary method of generating fasteners. 
           [0020]      FIG. 6A  shows a cross-section view of another exemplary sheet. 
           [0021]      FIG. 6B  shows a top view of the sheet in  FIG. 6A . 
           [0022]      FIG. 7A  shows a cross-section view of another exemplary sheet with a fiber mat as an additional layer. 
           [0023]      FIG. 7B  shows a top view of the sheet in  FIG. 7A . 
           [0024]      FIG. 8  illustrates an exemplary multi-layer multi-axis sheet. 
           [0025]      FIG. 9A  shows a cross-section view of an exemplary multi-layer multi-axis prepreg sheet with a matrix material. 
           [0026]      FIG. 9B  shows a top view of the multi-axial prepreg sheet of  FIG. 9A . 
           [0027]      FIG. 10A  shows a cross-section view of a first article with fasteners and a cover. 
           [0028]      FIG. 10B  shows a cross-section view of a second article with fasteners and a cover. 
           [0029]      FIG. 11A  shows a cross-section view of the first article of  FIG. 10A  with the cover removed. 
           [0030]      FIG. 11B  shows a cross-section view of the second article of  FIG. 10B  with the cover removed. 
           [0031]      FIG. 12  shows a cross-section view of the two fiber articles of  FIG. 11A and 11B  interlocked together by the fasteners on both fiber sheets. 
           [0032]      FIG. 13A  shows a cross-section view of a first article without fasteners. 
           [0033]      FIG. 13B  shows a cross-section view of a second article without fasteners. 
           [0034]      FIG. 13C  shows a cross-section view of an exemplary fiber sheet with fasteners on both sides. 
           [0035]      FIG. 13D  shows a cross-section view of the two articles of  FIG. 13A and 13B  interlocked together by the fasteners of the fiber sheet of  FIG. 13C . 
           [0036]      FIG. 13E  shows a cross-section of view of two articles with fasteners interlocked together using the fiber sheet of  FIG. 13C . 
           [0037]      FIG. 14A  illustrates a sheet with extension studs and windows. 
           [0038]      FIG. 14B  shows a cross-section view of the sheet of  FIG. 14A  being placed between two sheets with fasteners. 
           [0039]      FIG. 14C  shows a cross-section view of the sheet of  FIG. 14A  being placed within a roll of sheets with fasteners. 
           [0040]      FIG. 15A  illustrates an exemplary fiber-sheet handling tool. 
           [0041]      FIG. 15B  illustrates another exemplary fiber-sheet handling tool. 
           [0042]      FIG. 15C  illustrates yet another exemplary fiber-sheet handling tool. 
           [0043]      FIG. 16A  illustrates a cutting wheel made of multiple fiber sheets. 
           [0044]      FIG. 16B  shows a cross-section view of the cutting wheel of  FIG. 16A . 
           [0045]      FIG. 17A  illustrates an exemplary sheet with fasteners of different length and stiffness on two sides. 
           [0046]      FIG. 17B  illustrates two sheets of  FIG. 17A  interlocked together by fasteners of different length and stiffness. 
           [0047]      FIG. 17C  shows a close-up cross-section view of the sheet of  FIG. 17A . 
           [0048]      FIG. 18A  shows a cross-section view of an exemplary sheet with openings. 
           [0049]      FIG. 18B  shows a cross-section view of the sheet of  FIG. 18A  coupled with a stopping plate or film. 
           [0050]      FIG. 19A  and  FIG. 19B  are photos of a prototype showing fasteners with acute angle engaged and interlocked. 
           [0051]      FIG. 20A  illustrates an exemplary tire that can be at least partially made of fiber sheet with fasteners. 
           [0052]      FIG. 20B  shows a cross-section view of a portion of the tire of  FIG. 20A . 
           [0053]      FIG. 21  illustrates an exemplary composite panel or block. 
       
    
    
     DETAILED DESCRIPTION 
       [0054]    Embodiments of the invention provide apparatuses and methods for improving inter-laminate and interface strength of composites. Trans-laminate and cross-interface reinforcements, such as fasteners, on the fiber sheets are configured to engage and interlock to provide trans-laminate and cross-interface reinforcement. These techniques utilize traditional textile industry technologies, non-weaving technologies, and hook and loop (e.g., Velcro) technologies, and are compatible with traditional low cost 2-D manufacturing process. The trans-laminate and cross-interface reinforcements help to increase impact and wearing resistance, improve thermal and/or electrical conductivity, enhance fatigue durability, extend usage life, advance manufacturability of composites, and expand applications of composite. 
         [0055]    Referring now to  FIG. 1 , an exemplary sheet of fibers or substrate  10  has fasteners  29  on both sides of the sheet or substrate. The fasteners can be in the form of hooks  11 , loops  12 , anchor-shape hooks  13 , fish hooks  14 , forks  17  and  21 , big heads  18 , arrow-shape hooks  19 , group loops  20 , or group hooks  15  and  16 . The group hooks  15  or  16  can include multiple hooks to form chains of hook strings. The hooks  11 ,  13 ,  14 ,  15 ,  16 , or  19  can include multiple threads  22  in different lengths. The fasteners  29  can form a pattern. One example of patterns is an array on the sheet or substrate  10  with specified directions. The fasteners  29  can also be randomly scattered or mixed on the sheet or substrate  10 . The sheet or the substrate  10  can include multiple plies  101  and  102 . The terms “ply” and “sheet” can be used to describe different physical structures, including but not limited to, thread, filament, strand, yarn, layer, or multiple plies formed as one ply/sheet. 
         [0056]    As illustrated in  FIG. 2 , several sheets or substrates  10  are laid together layer-by layer to form a composite preform  30 . The fasteners (e.g., hooks and loops) can be configured to engage each other to provide trans-layer, inter-layer, and interface reinforcements. The trans-layer fasteners make composite preform  30  a 3-D composite. Preferably, the top sheet and the bottom sheet have fasteners only on the inner side (i.e., the side facing an adjacent sheet) of the sheets. As discussed above, the sheet or the substrate  10  can include multiple plies  101  and  102 . 
         [0057]    In one embodiment, the multiple-ply sheet  10  is a sheet of prepreg infiltrated with a polymer matrix (e.g., epoxy or resin).  FIG. 3  illustrates that the polymer matrix  35  infiltrates the sheet  10  to form a piece of prepreg  33 .  FIG. 4  shows a cross-section view of prepreg  33  with fasteners  31 ,  37 , and  38 . A portion of fasteners  31 ,  37 , and  38  can be at least partially above the polymer matrix  35 ; other fasteners can be completely under the surface of the polymer matrix  35 . The polymer matrix  35  covers at least some of the fasteners and helps to protect those fasteners and prevent them from engaging other fasteners on an adjacent sheet. Preferably, the polymer matrix  35  can have at least one indented portion  36  which is lower than its surrounding area. The indented portions  36  can be created by means such as cutting or molding. The indented portion  36  further helps to protect the fasteners  31 ,  37 , and  38  and prevent them from engaging other fasteners on an adjacent sheet. The fasteners covered or protected by the polymer matrix  35  can be exposed when the polymer matrix  35  becomes liquid and flows away during the curing process. 
         [0058]      FIG. 5  illustrates some methods of generating fasteners  11  and  12 . In one embodiment, a mold or heat iron  39  is configured to press the sheet to form fasteners (e.g., hooks and loops)  11  and  12  of certain shapes, angles, directions, and dimensions. In another embodiment, certain chemical gas or vapor is configured to flow through the sheet surface to form fasteners (e.g., hooks and loops)  11  and  12  of certain shapes, angles, directions, and dimensions. Alternatively, the fasteners  11  and  12  can be bonded on, glued on, weld on, compressed on, wrapped on, attached to, disposed on, embedded in, or grown on the sheet or ply. In addition, fasteners can be placed on sheets by air or water jet shoot. A combination of multiple generating methods described herein can also be used. 
         [0059]    Fiber sheets can be made by existing textile industry technologies such as weaving, knitting, wrapping, braiding, stitching, and hook and loop (Velcro®) technologies, or non-weaving technologies (e.g., molding, coating, or needle penetrating). Velcro® loops are generally made by weaving or knitting. Velcro® loops are cut at the desired locations to form Velcro® hooks. Cutting can be achieved by knives, scissors, or other physical, chemical, and mechanical means. For example, laser can be used to cut loops to form hooks. 
         [0060]      FIG. 6A  shows a cross-section view of another exemplary sheet  10 . Sheet  10  is made of at least two layers of fibers  101  and  102 . Each fiber layer can optionally have trans-layer fasteners (e.g., hooks and loops). The at least two layers  101  and  102  can be fastened together by weaving, knitting, and/or stitching. The top view of sheet  10  is shown in  FIG. 6B . 
         [0061]      FIG. 7A  shows a cross-section view of yet another exemplary sheet  10 . Sheet  10  is made of at least two layers of fibers  101  and  102 . Each fiber layer can optionally have trans-layer fasteners (e.g., hooks and loops). Sheet  10  can optionally have a fiber mat or a substrate  103  as an additional layer. The fiber mat or substrate  103  can be placed outside the two layers of fibers  101  and  102 ; alternatively, it can be sandwiched between two layers of fibers  101  and  102 . The at least two layers  101  and  102  and the optional fiber mat or substrate layer  103  can be fastened together by weaving, knitting and/or stitching. The top view of sheet  10  is showed in  FIG. 7B . 
         [0062]      FIG. 8  illustrates an exemplary multi-layer multi-axis sheet  10 . Sheet  10  is made of multiple layers of fibers  101 A,  101 B,  102 A, and  102 B. Each fiber layer can optionally have trans-layer fasteners (e.g., hooks and loops). Fibers in the same layer are approximately lined up in the same direction or axis. Fibers in different layers can be lined up to different directions or axes, forming a multi-layer, multi-axis sheet, as shown in  FIGS. 8 ,  9 A, and  9 B. The multiple layers  101 A,  101 B,  102 A, and  102 B can be bonded together by weaving, knitting, and/or stitching. Sheet  10  can optionally have a matrix material  35  flowed into it to form a prepreg, as shown in  FIG. 9A . 
         [0063]    In many situations two or more composite structures need to be connected or bonded. Fasteners at the connection area help to improve the connection strength.  FIG. 10A  shows a cross-section view of a first article  100 A with fasteners  11  and  12  and a first cover  104 A covering at least a portion of the first article. The first article  100 A can be a single-layer or multi-layer fiber sheet, a composite part, or a substrate.  FIG. 10B  shows a cross-section view of a second article  100 B with fasteners and a second cover  104 B covering at least a portion of the second article. The second article  100 B can also be a single-layer or multi-layer fiber sheet, a composite part, or a substrate. The covers  104 A and  104 B help to protect the covered fasteners  11  and  12  and prevent them from pressing down, engaging, and interlocking each other during production processes, such as curing and molding. 
         [0064]    The covers  104 A and  104 B can be made of materials, such as paper, silicone, rubber, polymer, metal wax, paste, powder, etc. The covers can also be made of mixtures of the aforementioned materials. In one embodiment, a low melting-point alloy suitable for room temperature curing processes is used to cover the fasteners. One example of such an alloy is a eutectic alloy, made of about 50% bismuth, about 26.7% lead, about 13.3% tin, and about 10% cadmium by weight, and with a melting point of approximately 70° C. (158° F.). During the curing process, the covers can be removed by heat and the covered fasteners can then be exposed. In another embodiment, wax and RTV silicone are used to cover the fasteners. At first, wax is applied as sizing to coat the fasteners, in order to achieve a relatively smooth surface. Then RTV silicone is used to cover the fasteners. During the curing process, RTV silicone cover can be peeled away or be removed by heat or chemical solutions; wax coating can be removed by heat or by chemical solutions. 
         [0065]    When the two articles  100 A and  100 B are ready to be connected, the covers  104 A and  104 B can be removed by mechanical, physical and/or chemical means to expose the fasteners, as shown in  FIGS. 11A and 11B . The fasteners  11  and  12  on articles  100 A and  100 B are then engaged and interlocked together to form a connection/bonding between the first article  100 A and the second article  100 B, as shown in  FIG. 12 . The connected articles can optionally have a matrix material  35  incorporated at the connection area for at least one subsequent curing process. 
         [0066]      FIG. 13A  shows a cross-section view of a first article  200 A without any fastener. The first article  200 A can be a single-layer or multi-layer fiber sheet, a composite part, or a substrate.  FIG. 13B  shows a cross-section view of a second article  200 B without any fastener. The second article  200 B can also be a single-layer or multi-layer fiber sheet, a composite part, or a substrate.  FIG. 13C  shows a cross-section view of an exemplary fiber sheet  200 C with fasteners on both sides. The fiber sheet  200 C can be sandwiched between two articles  200 A and  200 B at the connection area, as shown in  FIG. 13D . The fasteners on the fiber sheet  200 C can lock onto the articles  200 A and  200 B and thus help to improve the connection strength of articles  200 A and  200 B. Alternatively, as shown in  FIG. 13E , two articles to be connected  300 A and  300 B can have their own fasteners at the connection area. The fiber sheet  200 C can still be sandwiched between two articles  300 A and  300 B at the connection area. The fasteners on the fiber sheet  200 C can engage and interlock with the fasteners on articles  300 A and  300 B and thus help to improve the connection strength of articles  300 A and  300 B. The connected articles can optionally have matrix material  35  incorporated at the connection area for at least one subsequent curing process. 
         [0067]    Referring now to  FIG. 14A , a sheet  105  can have upstanding or protruding studs  106 , windows  107 , and/or walls  108 . The sheet  105  can be made of paper, plastic, or other materials by press molding, injection molding, and/or other means. The upstanding or protruding studs  106  and walls  108  can be mounted or welded on to the sheet  105 . The upstanding or protruding studs  106  walls  108  can also be generated on the sheet  105  by means such as press molding. The windows  107  can be created by means such as cutting or molding. The sheet  105  can be placed between two sheets with fasteners  10 , as shown in  FIG. 14B . The upstanding or protruding studs  106 , walls  108 , and windows  107  help to create spaces between two sheets  10  and protect the fasteners  11  and  12  during production and transportation process, such as layering and rolling.  FIG. 14C  illustrates that the sheet  105  with upstanding or protruding studs  106 , walls  108 , and windows  107  separates and protects fasteners  11  and  12  in a sheet roll  10 A. 
         [0068]    Automatic handling of fiber sheets has been and is still a big challenge in the composite industry. In many situations, the task of lying up fiber sheet is still performed manually, i.e. by hand, mostly due to the lack of effective tools. The present invention describes fiber-sheet handling tools that can be configured to be driven by manual, electrical, hydraulic, magnetic, and/or mechanical forces. One embodiment of a fiber-sheet handling tool  108  according to the present invention is shown in  FIG. 15A . Fiber-sheet handling tool  108  includes a base  115  and a connector  99 . The connector  99  is capable of being coupled to a control signal and/or a manual, electrical, hydraulic, magnetic, and/or mechanical driving force. The tool  108  has at least one rod  109  that is positioned within a housing unit  114 . The rod  109  has fasteners  11  and  12  on some portion of its surface. The rod  109  is rotatable by manual, electrical, hydraulic, magnetic, and/or mechanical driving force. In operation, the tool  108  is positioned adjacent to the sheet  10  with fasteners  11 ′ and  12 ′. When the rod  109  is rotated to expose its fasteners  11  and  12 , the fasteners  11  and  12  engage and interlock with the fasteners  11 ′ and  12 ′ on the sheet  10 . The engagement and interlocking of fasteners allows the tool  108  to grab the sheet  10 . When the rod  109  is rotated to hide its fasteners  11  and  12 , the fasteners  11  and  12  disengage and unlock from the fasteners  11 ′ and  12 ′ of the sheet  10 . The disengagement and unlocking of fasteners allows the tool  108  to release the sheet  10 . 
         [0069]    Another embodiment of a fiber-sheet handling tool  108 ′ according to the present invention is shown in  FIG. 15B . Fiber-sheet handling tool  108 ′ includes a base  115 ′ and a connector  99 ′. The base  115 ′ has fasteners  11  and  12  on at least some portion of its bottom contact surface. The connector  99 ′ is capable of being coupled to a control signal and/or a manual, electrical, hydraulic, magnetic, and/or mechanical driving force. The base  115 ′ can also optionally have an axis  111  to further couple to an additional driving force. The tool  108 ′ has at least one bar  110  that is positioned within a housing unit  114 ′. The bar  110  is retractable by manual, electrical, hydraulic, magnetic, and/or mechanical driving force. In operation, the tool  108 ′ is positioned adjacent to the sheet  10  with fasteners  11 ′ and  12 ′. When the bar  110  is retracted to recess within the housing unit  114 ′, the fasteners  11  and  12  of the bottom contact surface of the base  115 ′ engage and interlock with the fasteners  11 ′ and  12 ′ on the sheet  10 . The engagement and interlocking of fasteners allows the tool  108 ′ to grab the sheet  10 . When the bar  110  is extended to protrude outside the housing unit  114 ′, the fasteners  11  and  12  of the bottom contact surfaced of the base  115 ′ disengage and unlock from the fasteners  11 ′ and  12 ′ of the sheet  10 . The disengagement and unlocking of fasteners allows the tool  108 ′ to release the sheet  10 . In a variation of this embodiment, the base  115 ′ has no fastener on its bottom contact surface; but the bar  110  has fasteners on at least some portion of its bottom contact surface. In operation, the tool  108 ′ is positioned adjacent to the sheet  10  with fasteners  11 ′ and  12 ′. When the bar  110  is extended from the housing unit  114 ′ to expose its fasteners, the fasteners of the bar  110  engage and interlock with the fasteners  11 ′ and  12 ′ on the sheet  10 . The engagement and interlocking of fasteners allows the tool  108  to grab the sheet  10 . When the bar  110  is retracted to recess into the housing unit  114 ′, the fasteners of the bar  110  disengage and unlock from the fasteners  11 ′ and  12 ′ of the sheet  10 . The disengagement of fasteners allows the tool  108 ′ to release the sheet  10 . 
         [0070]    Yet another embodiment of a fiber-sheet handling tool  108 ″ according to the present invention is shown in  FIG. 15C . Fiber-sheet handling tool  108 ″ includes a base plate  115 ″, a moving plate  113 , and a connector  99 ″. Both the base plate  115 ″ and the moving plate  113  have at least one pin  112 . The connector  99 ″ is capable of being coupled to a control signal and/or a manual, electrical, hydraulic, magnetic, and/or mechanical driving force. Pins  112  are capable to be fit into the gap between two sheets  10 . The moving plate  113  can be raised or lowered by manual, electrical, hydraulic, magnetic, and/or mechanical driving force. In operation, the tool  108 ″ is positioned adjacent to sheets  10  so that the pins  112  are configured to fit into the gap between two sheets. When the moving plate  113  is raised, the fasteners between sheets disengage and unlock from each other. The disengagement and unlocking allows the tool  108 ″ to separate and grab the sheet  10 . When the moving plate  113  is lowered, the fasteners between sheets engage and interlock with each other. The engagement and interlocking of fasteners allows the tool  108 ″ to release the sheet  10 . 
         [0071]    The 3-Dimension fiber structures for composites and interfaces have wide range of applications. For one example, a cutting wheel can be at least partially made of 3-Dimension fiber structures. One embodiment of such a cutting wheel is shown in  FIGS. 16A and 16B . In this embodiment, a plurality of sheets  10  with fasteners  11  and  12  are interlocked together, providing the cutting wheel with enhanced laminate strength. In addition, the exposed fasteners  11  and  12  on the outermost sheets can help to withhold and suppress particles  120  (e.g., sawdust) generated during the cutting process, increasing the usage life of the cutting wheel and associated equipments. The cutting wheel can be manufactured using conventional processes, with the exception that the individual layers are made of sheets with fasteners. For another example, a tire can be at least partially made of 3-Dimension fiber structures. One embodiment of such a tire is shown in  FIGS. 20A and 20B . In this embodiment, a plurality of sheets  10  with fasteners  11  and  12  are interlocked together. The fasteners  11  and  12  on at least one sheet  10  can also penetrate, engage, and interlock with at leas one other layer  145  of the tire, such as a fabrics or a net. The engagement and interlocking can form strong 3-D reinforcements in tires, providing features such as longer usage life, higher puncture-resistance, and stronger interlaminate strength. Sheets  10  and other layers  145  of a tire can be made of various materials, such as Kevlar, carbon fiber, glass fiber, steel wire, or other fiber materials. Sheets  10  in tires can optionally have matrix material  35  incorporated/applied for bonding. 
         [0072]    The 3-Dimension fiber structures for composites can also be used to manufacture structures with internal spaces.  FIG. 21  illustrates an example of such a structure. 
         [0073]    Several sheets or substrates  10  are laid together layer-by layer to form a composite panel or block  215  with hollow spaces inside. The fasteners (e.g., hooks and loops) can be configured to engage each other to provide inter-layer connections and supports. The stack of substrates  10  is not fully compressed; and thus, there is hollow space  211  between the substrates  10 . The fasteners  11  and  12  can act both as connectors/supports and as spacers between substrates  10  in a composite structure. The hollow space within the composite panel or block  215  helps to improve certain characteristics (e.g., thermal resistance) of the composite panel or block  215 . Such panel composite panels or blocks can be used in the construction industry, such as to make walls and doors. Preferably, the top sheet and the bottom sheet have fasteners only on the inner side of the sheets. Optionally, the top sheet and the bottom sheet do not have fasteners at all. Composite panel  215  can be manufactured by using a stack of prepreg sheets or by infiltrating the 3D stack of sheet  10  preform with resin. 
         [0074]    The fasteners on two sides of a sheet are not necessarily of the same length or same stiffness.  FIG. 17A  illustrates an exemplary sheet  100  with shorter and stiffer fasteners  121  on one side and longer and softer fasteners  122  on the other side. Fibers such as fiberglass and carbon fiber have different bending modulus. A shorter fastener is generally stiffer and harder against bending and buckling under a particular compression load. When shorter and stiffer fasteners  121  are pressed against longer and softer fasteners  122 , the shorter and stiffer fasteners  121  will normally engage and interlock with the longer and softer fasteners  122 , as shown in  FIG. 17B . The shorter and stiffer fasteners  121  on a sheet plane  10  can achieve an acute angle  124  leaning towards a desired direction by optimizing weaving and knitting technologies for making Velcro fasteners, towels, etc. Fasteners leaning with acute angle  124  can also be obtained by applying coating and sizing materials  123  at the desired location and direction on the fasteners in order to sharpen the leaning fasteners. Fasteners leaning with acute angle help to engage other fasteners on an adjacent sheet.  FIGS. 19A and 19B  are two photos of a prototype, showing fasteners with acute angle engaged and interlocked with each other. 
         [0075]    Referring now to  FIGS. 18A and 18B , another exemplary process of generating fasteners on a sheet is illustrated.  FIG. 18A  shows a cross-section view of an exemplary sheet  100  with at least one opening  35 . At first, matrix material  35  is applied to the inner walls of openings  35 . Then, flocking technologies, either via electrical field or mechanical means, is used to run fasteners  130  through openings  35  on sheet  100 . Optionally, fasteners  130  can be aligned by a plate or a film  131  to achieve a desired height/length above the surface of sheet  100 . 
         [0076]    The detailed descriptions above in connect with the corresponding figures are intended to illustrate the present invention, and are not intended to represent the only forms in which the present invention may be constructed and/or utilized. The descriptions set forth the structure and the sequence of steps for practicing the present invention in connection. It is to be understood, however, that the same or equivalent structures and steps may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention. Accordingly, it is not intended that the invention be limited except by the claims. 
         [0077]    It is noted that one or more references are incorporated herein. To the extent that any of the incorporated material is inconsistent with the present disclosure, the present disclosure shall control. Furthermore, to the extent necessary, material incorporated by reference herein should be disregarded if necessary to preserve the validity of the claims. 
         [0078]    Further, while the description above refers to the invention, the description may include more than one invention.