Forming tool of novel hollow fabric and method for forming composite material by using forming tool

Abstract

The invention provides a forming tool of a hollow fabric and a method for forming a composite material by using the forming tool. The forming tool comprises two fixed frames and a plurality of fixed core plates, wherein a plurality of limiting clamping grooves are formed in the two opposite side frames in each fixing frame, the upper end and the lower end of the fixing core plate are fixed to the fixing frames through the limiting clamping grooves respectively, and the fixing core plate is used for fixing the upper face layer, the lower face layer and the core layer of the hollow fabric; and a gap is formed between the adjacent fixed core plates. The forming tool is high in adaptability to the hollow fabric forming process, the types, the layer number and the distribution of the fabrics of the upper face layer and the lower face layer can be freely designed, the types, the distribution, the form and the combination of the free yarns of the core layer can be freely designed, and the hollow fabrics with different regional characteristics can be easily formed. The forming problem of a plane, a single curved surface, a double curved surface and other special-shaped molded surfaces can be solved, and the difficulty of multi-dimension, free design and forming of the hollow fabric is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of fabric and composite material preparation, and in particular to a new type of hollow fabric forming tool and a composite material forming method thereof. Background Art

[0002] Hollow fabric is a three-dimensional fabric that is woven into an integrated form. The upper and lower fabric surfaces are connected by Z-direction fibers, and a certain space is supported according to a certain rule in the thickness direction of the fabric.

[0003] In the related art, the forming methods of hollow fabrics are mainly divided into weaving and knitting, and the main technical principle is to connect the upper and lower surface layers or multiple surface layers through velvet warps or spacer yarns through rapier looms / weft knitting machines / warp knitting machines, etc.; however, the structural type, number of layers, yarn distribution, shape and surface accuracy of the hollow fabrics formed by the above-mentioned forming methods are all limited by the hardware configuration and working conditions of the loom itself, so that the structural and functional design of the prepared hollow fabric is limited to the weavability / manufacturability of the loom equipment, and the fabric design space is seriously insufficient, which cannot meet the needs of material preparation requiring different forming methods / process requirements for different levels, or one-time forming of multifunctional layer composite materials.

[0004] Therefore, based on the above problems, there is an urgent need to provide a new type of hollow fabric molding tool and a method for molding a composite material. Summary of the invention

[0005] The embodiments of the present invention provide a new type of hollow fabric molding tooling and a method for molding composite materials, which can solve the problem that traditional hollow fabric molding methods cannot meet the material preparation requirements of different molding methods / processes for different levels, or the need for one-time molding of multifunctional layer composite materials.

[0006] In the first aspect, the present invention provides a new type of hollow fabric forming tooling, comprising two fixed frames and a plurality of fixed core plates; wherein, each of the two opposite side frames in the fixed frame is provided with a plurality of limiting slots, and the upper and lower ends of the fixed core plate are respectively fixed to each fixed frame through the limiting slots, and the fixed core plate is used to fix the upper and lower layers and the core layer of the hollow fabric; there is a gap between adjacent fixed core plates.

[0007] Preferably, the cross-sectional shape of the fixed core plate is at least one of square, rectangular, circular, elliptical or polygonal;

[0008] The outer shape of the fixing frame is flat, curved or special-shaped.

[0009] Preferably, the length of the fixed core plate is greater than the length of the fixed frame.

[0010] In a second aspect, the present invention provides a method for forming a novel hollow fabric using a forming tool according to any one of the first aspects above, the method comprising:

[0011] (1) determining the molding parameters of the molding tool according to the characteristic parameters of the pre-designed hollow fabric; wherein the characteristic parameters include the profile type, outer dimensions, cavity shape, cavity distribution and cavity density of the hollow fabric, and the molding parameters include the outer profile and dimensions of the fixed frame, and the dimensions, material and quantity of the fixed core plate;

[0012] (2) according to the characteristic parameters of the pre-designed hollow fabric, the fabric body is fixedly formed by using the forming tool; wherein different fabric bodies correspond to different forming methods;

[0013] (3) After molding, the fixed frames of the upper and lower layers of the hollow fabric are removed, and the hollow fabric preform is composite-molded by a resin composite molding process, and the novel hollow fabric composite material is obtained after removing the fixed core plate.

[0014] Preferably, the profile types of the hollow fabric include flat type, curved type and special-shaped type;

[0015] The material of the fixed core plate is determined based on the surface type of the hollow fabric; preferably, when the hollow fabric is planar, the fixed core plate is a rigid fixed core plate, and when the hollow fabric is curved, the fixed core plate is a flexible fixed core plate.

[0016] Preferably, the fabric body comprises two fabric surface layers;

[0017] The method of fixing and shaping the fabric by using the forming tool according to the pre-designed characteristic parameters of the hollow fabric comprises:

[0018] Fix the fixed core plates to the fixed frame one by one through the limit slots according to the pre-designed cavity density and distribution;

[0019] Laying the fabric surface layer in the upper and lower fixed frames respectively, so that the upper and lower surfaces formed by the plurality of fixed core plates are respectively in contact with the fabric surface layer;

[0020] According to the pre-designed pile warp distribution pattern, the yarn is introduced in sequence from top to bottom or from bottom to top along the gap between adjacent fixed core plates, so that the yarn is distributed along the contour of the fixed core plate and connects the upper and lower fabric layers to obtain the novel hollow fabric.

[0021] Preferably, the fabric body is a hollow fabric, and the hollow fabric comprises an upper and lower surface layer and a core layer connected to the upper and lower surface layer, and the core layer is obtained by evenly arranging a plurality of pile warp layers, and a pile warp cavity is formed between adjacent pile warp layers;

[0022] The method of fixing and shaping the fabric by using the forming tool according to the pre-designed characteristic parameters of the hollow fabric comprises:

[0023] Inserting the fixed core plate between the pile warp cavities of the hollow fabric according to the pile warp cavity distribution of the hollow fabric, so that the upper and lower surfaces of the fixed core plate are completely in contact with the upper and lower layers of the hollow fabric, to obtain a fabric preform;

[0024] A fixed frame is placed on the upper and lower surfaces of the fabric preform, and the fixed core plate is limited and fixed by using the limiting slots in the fixed frame;

[0025] According to the pre-designed yarn distribution pattern, the yarn is introduced in sequence from top to bottom or from bottom to top along the gap between adjacent fixed core plates, so that the yarn is distributed along the contour of the fixed core plate and connects the upper and lower fabric layers to obtain the novel hollow fabric.

[0026] Preferably, before fixing the fixed core plate by the limiting slot or inserting the fixed core plate along the hollow fabric pile cavity, the method further includes applying a release agent on the surface of the fixed core plate.

[0027] Preferably, before placing the hollow fabric in step (2) in a molding tool for fixed molding, the method further includes laying a functional layer or a skin layer on the upper and lower surfaces of the fabric body.

[0028] In a third aspect, the present invention provides a novel hollow fabric composite material, which is formed by the method described in any one of the second aspects above.

[0029] Compared with the prior art, the present invention has at least the following beneficial effects:

[0030] (1) In the present invention, the molding tooling of the new hollow fabric is designed as two fixed frames and a plurality of fixed core plates, and the fixed core plates are fixed by the limit slots in the fixed frames. During the molding process of the hollow fabric composite material, the molding parameters of the molding tooling are first designed according to the characteristic parameters of the pre-designed hollow fabric, and then the fixed frame and the fixed core plate are matched to fix the fabric body, and after being removed from the fixed frame, the hollow fabric is compositely molded by a resin composite molding process, thereby obtaining a new hollow fabric composite material. The above-mentioned molding tooling has strong adaptability to the process of hollow fabric molding, and can realize the free design of the fabric types, layers, and distribution of the upper and lower layers, and the free design of the types, distribution, form, and combination of the core layer free yarns. While easily forming hollow fabrics with different regional characteristics, it can solve the molding problems of planes, single curved surfaces, hyperbolic surfaces, and other special-shaped surfaces, greatly reducing the difficulty of multi-dimensional, free design and molding of hollow fabrics.

[0031] (2) The molding method of the present invention is easy to implement and has strong operability. For materials that require different molding methods / process requirements at different levels in the composite material design, or multifunctional layer composite materials that cannot be molded in one go, this technology will be able to realize their integrated molding solution, while eliminating the interface strength problem between different materials. At the same time, it is conducive to realizing the functional superposition of the existing hollow fabric velvet layer, and realizing the highly integrated integrated molding preparation of different functional areas; it can greatly enrich the hollow fabric structure, improve the preparation efficiency of complex configuration hollow fabrics and their composite materials, and effectively reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 It is a schematic diagram of the overall structure of a new type of hollow fabric forming tooling provided by one embodiment of the present invention;

[0034] Figure 2 It is a structural schematic diagram of a fixing frame in a new type of hollow fabric forming tooling provided by one embodiment of the present invention;

[0035] Figure 3 It is a top view of a novel hollow fabric formed by a forming tool provided by an embodiment of the present invention;

[0036] Figure 4 It is a distribution design diagram of free yarn traces in the Z direction during the forming process of a novel hollow fabric provided by one embodiment of the present invention;

[0037] Figure 5 and Figure 6 Schematic diagram of the structure of the novel hollow fabric before and after composite molding provided by Example 1 of the present invention;

[0038] Figure 7 and Figure 8 It is a top view and a cross-sectional structural view of the surface layer of the glass fiber area after the new hollow fabric composite molding provided in Example 1 of the present invention;

[0039] Fig. 9 and Fig.10 It is a top view and a cross-sectional structural view of the surface layer of the carbon fiber-lamination region of the novel hollow fabric after composite molding provided by Example 1 of the present invention;

[0040] In the figure, 100-fixed frame, 200-fixed core plate, 201-core plate gap / suture needle introduction / exit point, 202-yarn, 203-suture needle, 301-fabric upper layer, 302-fabric lower layer, 101-frame, 1011-limiting slot. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0042] like Figure 1 and Figure 2 As shown, an embodiment of the present invention first provides a new type of hollow fabric forming tooling, which includes two fixed frames 100 and a plurality of fixed core plates 200; wherein, a plurality of limiting slots 1011 are provided on the two opposite side frames 101 in each of the fixed frames 100, and the upper and lower ends of the fixed core plates 200 are respectively fixed to each of the fixed frames 100 through the limiting slots 1011, and the fixed core plates 200 are used to fix the upper and lower layers and the core layer of the hollow fabric; there are gaps between adjacent fixed core plates.

[0043] In the embodiment of the present invention, Figure 1 As shown, the forming tooling of the new hollow fabric is designed as two fixed frames 100 and several fixed core plates 200, and the fixed core plates 200 are fixed by the limit slots 1011 in the fixed frames 100. During the forming process of the hollow fabric composite material, the forming parameters of the forming tooling are first designed according to the pre-designed characteristic parameters of the hollow fabric, and then the fixed frame 100 and the fixed core plate 200 are matched to fix the fabric body, and the hollow fabric is compositely formed by the resin composite forming process after being removed from the fixed frame, so as to obtain a new hollow fabric composite material. The above-mentioned forming tooling has strong adaptability to the process of hollow fabric forming, and can realize the free design of the fabric types, layers and distribution of the upper and lower layers, and the free design of the types, distribution, form and combination of the core layer free yarns. While it is easy to form hollow fabrics with different regional characteristics, it can solve the forming problems of planes, single curved surfaces, hyperbolic surfaces and other special-shaped surfaces, greatly reducing the difficulty of multi-dimensional, free design and forming of hollow fabrics.

[0044] According to some preferred embodiments, the cross-sectional shape of the fixed core plate is at least one of square, rectangular, circular, elliptical or polygonal; the outer shape of the fixed frame is flat, curved or irregular.

[0045] In an embodiment of the present invention, the outer shape of the fixed frame includes but is not limited to a plane and a curved surface (including single curvature or multiple curvatures), and it can also be designed as a special-shaped shape according to the requirements of the hollow fabric surface; and the fixed core plate can be in different shapes, such as square, rectangular or elliptical, etc., so that the design of different velvet warp structures in the hollow fabric core layer can be realized; at the same time, in order to ensure that the fixed frame has a better fixing effect, the material of the fixed frame includes but is not limited to various metals, polytetrafluoroethylene plastics, wood and other organic or inorganic materials.

[0046] According to some preferred embodiments, the length of the fixed core plate 200 is greater than the length of the fixed frame 100 .

[0047] Continue to refer Figure 1 In the embodiment of the present invention, the length of the fixed core plate 200 is greater than the length of the fixed frame 100, so that the fixed core plate 200 is conveniently fixed to the fixed frame 100 through the limiting card groove 1011, and is conveniently removed from the fixed frame after the resin and the hollow fabric are compounded.

[0048] The embodiment of the present invention further provides a method for forming a novel hollow fabric using any of the above-mentioned forming tooling, the method comprising:

[0049] (1) determining the molding parameters of the molding tool according to the characteristic parameters of the pre-designed hollow fabric; wherein the characteristic parameters include the profile type, outer dimensions, cavity shape, cavity distribution and cavity density of the hollow fabric, and the molding parameters include the outer profile and dimensions of the fixed frame, and the dimensions, material and quantity of the fixed core plate;

[0050] (2) according to the characteristic parameters of the pre-designed hollow fabric, the fabric body is fixedly formed by using the forming tool; wherein different fabric bodies correspond to different forming methods;

[0051] (3) After molding, the fixed frames of the upper and lower layers of the hollow fabric are removed, and the hollow fabric preform is composite-molded by a resin composite molding process, and the novel hollow fabric composite material is obtained after removing the fixed core plate.

[0052] The molding parameters of the molding tool and the like determine the characteristic parameters of the preformed hollow fabric. Therefore, in the embodiment of the present invention, the molding tool is designed and prepared according to the pre-designed hollow fabric profile type, external dimensions, cavity morphology, cavity distribution and density, including a fixed frame with corresponding profile and external dimensions and a fixed core plate consistent with the cavity morphology of each region. The fixed core plates are arranged one by one according to the density, distribution and molding profile requirements of the designed hollow fabric cavity and fixed on the fixed frame through the limit card slot. At this time, the upper and lower surfaces of the fixed core plates linearly arranged with the fixed frame form the profile of the hollow fabric core layer to be prepared, and the height of the fixed core plate is the cavity height of the hollow fabric to be prepared. Finally, the fabric body is fixed and formed using the molding tool, and further combined with the resin composite molding process to achieve the molding of the new hollow fabric composite material.

[0053] It can be understood that the resin composite molding process can be selected according to the process in the prior art. For example, composite molding methods such as vacuum infusion process, hand lay-up process, autoclave process, molding process, and impregnation process can be used to fully infiltrate the hollow fabric preform with resin (epoxy resin, unsaturated resin, phenolic resin and aromatic acetylene resin, etc.); heat and cure according to the preset process, and obtain a hollow fabric composite material with different regional characteristics after removing the fixed core plate.

[0054] According to some preferred embodiments, the surface types of the hollow fabric include flat, curved and special-shaped types; the material of the fixed core plate is determined based on the surface type of the hollow fabric; preferably, when the hollow fabric is flat, the fixed core plate is a rigid fixed core plate, and when the hollow fabric is curved, the fixed core plate is a flexible fixed core plate.

[0055] Considering that the hollow fabric can be designed into a variety of surface types (such as flat, curved or special-shaped), in the embodiment of the present invention, when the pre-designed hollow fabric is flat, the fixed core plate in the molding tool uses a rigid fixed core plate to support the core layer of the hollow fabric, and a flat fixed frame is used to support the upper and lower layers of the hollow fabric and the fixed core plate. When the pre-designed hollow fabric is curved (single curvature type, double curvature type, etc.), the fixed core plate in the molding tool uses a flexible fixed core plate to support the core layer of the hollow fabric, and a curved fixed frame is used to support the upper and lower layers of the hollow fabric and the fixed core plate. In this way, when the hollow fabric is molded by the molding tool, high-precision molding of hollow fabrics of various surface types can be achieved.

[0056] The forming tool in the embodiment of the present invention can use different fabrics as the main body to realize the forming design of hollow fabrics and composite materials with different structures and functions. Specifically, when the fabric main body used includes only two fabric surface layers, the method of fixing and forming the fabric using the forming tool is as follows:

[0057] Fix the fixed core plates to the fixed frame one by one through the limit slots according to the pre-designed cavity density and distribution;

[0058] Laying the fabric surface layer in the upper and lower fixed frames respectively, so that the upper and lower surfaces formed by the plurality of fixed core plates are respectively in contact with the fabric surface layer;

[0059] According to the pre-designed pile warp distribution pattern, the yarn is introduced in sequence from top to bottom or from bottom to top along the gap between adjacent fixed core plates, so that the yarn is distributed along the contour of the fixed core plate and connects the upper and lower fabric layers to obtain the novel hollow fabric.

[0060] In the embodiment of the present invention, in order to realize the forming of the hollow fabric, as Figure 3 As shown, after the assembly of the forming tooling is completed, two fabric surface layers are first laid in the fixed frame, and they are respectively attached to the molded surface formed by several fixed core plates. At this time, the fabric surface layers of the upper and lower layers form the upper and lower layers of the hollow fabric to be prepared; to avoid slippage, the edges of the fabric surface layers can be fixed to the fixed frame structure layer by layer by bonding. Afterwards, according to the preset velvet warp distribution form, the yarn is introduced from top to bottom or from bottom to top along the gap of the fixed core plate using a suture needle. During the introduction process, the yarn passes through the upper (lower) fabric surface layer, the outer edge of the fixed core plate and the lower (upper) fabric surface layer in turn, so that the yarn is distributed along the outer contour of the fixed core plate and connected with the upper and lower fabric layers, thereby forming a Z-direction free yarn with a specific form; then, according to the stitches and density set in different regions, the Z-direction free yarn is introduced in sequence in different regions, and the upper and lower fabric layers of the fabric are connected to obtain a hollow fabric with different regional characteristics.

[0061] According to some preferred embodiments, when the fabric body used is a hollow fabric, the hollow fabric includes an upper and lower surface layer and a core layer connected to the upper and lower surface layer, and the core layer is obtained by evenly arranging a plurality of pile warp layers, and a pile warp cavity is formed between adjacent pile warp layers, the method of fixing and molding the fabric using a molding tool is as follows:

[0062] Inserting the fixed core plate between the pile warp cavities of the hollow fabric according to the pile warp cavity distribution of the hollow fabric, so that the upper and lower surfaces of the fixed core plate are completely in contact with the upper and lower layers of the hollow fabric, to obtain a fabric preform;

[0063] A fixed frame is placed on the upper and lower surfaces of the fabric preform, and the fixed core plate is limited and fixed by using the limiting slots in the fixed frame;

[0064] According to the pre-designed yarn distribution pattern, the yarn is introduced in sequence from top to bottom or from bottom to top along the gap between adjacent fixed core plates, so that the yarn is distributed along the contour of the fixed core plate and connects the upper and lower fabric layers to obtain the novel hollow fabric.

[0065] In the embodiment of the present invention, when the hollow fabric is used as the fabric body, the fixed core plates can be first inserted and fixed along the velvet warp cavity channels of the hollow fabric, and then fixed frames can be placed on the upper and lower surfaces thereof; or the edges of the upper layer of the hollow fabric can be first fixed to the fixed frame structure by bonding, and then fixed core plates with the same shape and size as the velvet warp cavity can be placed in each velvet warp cavity in the core layer of the hollow fabric body, so that the upper and lower surfaces of the fixed core plates are respectively fitted with the upper and lower layers of the hollow fabric, and the fixed frame is fixedly connected to the lower end of each fixed core plate through a limiting slot, so that the lower layer of the hollow fabric is located inside the fixed frame.

[0066] On the basis of the existing velvet warp of the hollow fabric, the functional Z-direction free yarn with regular arrangement + random arrangement is superimposed and designed, and the suture needle is introduced from bottom to top (or from top to bottom) along the gap between the core rods. The suture needle and thread pass through the lower (upper) surface fabric, the outer edge of the fixed core plate and the upper (lower) surface fabric in turn, so that the yarn is distributed along the outer contour of the fixed core plate and connected with the upper and lower surface fabrics to form a Z-direction free yarn with a specific shape. Then, according to the stitches and density set in different areas, the Z-direction free yarn is introduced in sequence in different areas, and the upper and lower fabrics are connected to form a hollow fabric with different regional characteristics. In this way, the functions of the velvet warp layer can be superimposed on the existing hollow fabric, thereby realizing highly integrated integrated molding preparation of different functional areas.

[0067] According to some preferred embodiments, before fixing the fixed core plate through the limiting slot or inserting the fixed core plate along the hollow fabric pile cavity, the step of applying a release agent on the surface of the fixed core plate is also included.

[0068] In an embodiment of the present invention, a release agent is evenly applied to the surface of the fixed core plate, which facilitates the removal of the fixed core plate after the resin and the hollow fabric are composited and formed, thereby avoiding damage to the structure of the hollow fabric during the demoulding process and achieving effective forming of the hollow fabric composite material.

[0069] According to some preferred embodiments, before placing the hollow fabric in step (2) in a molding tool for fixed molding, the process further includes laying a functional layer or a skin layer on the upper and lower surfaces of the fabric body.

[0070] In the embodiments of the present invention, the surface layer can be thickened or a functional layer can be superimposed on the existing hollow fabric / fabric surface layer, or the Z-direction free yarn can be designed to be superimposed in a layer throughout the hollow fabric with different surface layer thickness levels, and introduced multiple times according to the set thickness levels to achieve improved failure resistance and damage tolerance of the surface layer.

[0071] At the same time, when all / part of the surface fabrics in the hollow fabric forming process are replaced with composite materials, the hollow structure fabric / composite body can also be formed by the method in the embodiment of the present invention, and the subsequent composite forming process can also be carried out. During the forming process, several microporous structures can be processed on the surface of the hollow fabric composite material, and then the functional fabric (such as an elastomer with buffering and vibration isolation function, several layers of heterogeneous composite materials) is draped on the upper / lower surface of the composite material. When a heterogeneous composite material is used, it is necessary to process several through micropores at the same position relative to the surface of the heterogeneous composite material and the surface of the hollow fabric composite material. The suture needle is introduced from bottom to top (or from top to bottom) along the position where the micropores are located, and the suture needle and thread pass through the lower (upper) surface layer functional fabric, the hollow fabric and the upper (lower) surface layer functional fabric in turn, so that the yarn is distributed along the outer contour of the fixed core plate and the upper and lower functional fabrics are connected to the hollow fabric composite body to form a Z-direction free yarn with a specific shape; thereby realizing the positioning, connection and endowment of the surface functional layer of the hollow fabric composite material.

[0072] It should be noted that, in the embodiment of the present invention, the distribution form of the Z-direction free yarn can be designed into different forms according to actual needs, the suturing methods include but are not limited to manual suturing, quilting equipment suturing and robotic arm programmed controlled suturing, etc., the suturing needle can be designed as a straight needle, an arc needle or a special shape according to the mandrel shape, and the types of Z-direction free yarn include but are not limited to glass fiber yarn, carbon fiber yarn, polyimide fiber yarn, metal wire, ceramic fiber yarn, high elastic wire, etc.

[0073] Types of fabric surface layers include but are not limited to woven fabrics, knitted fabrics, braided fabrics, non-woven fabrics, special fabrics, elastomers with buffering and vibration isolation functions, etc. Fabric materials include but are not limited to glass fiber, carbon fiber, metal film / fabric, polyurethane and other elastomeric plastics, etc.

[0074] Types of heterogeneous composite materials include but are not limited to elastomers with buffering and vibration isolation functions, sound-absorbing materials, wave-absorbing materials, etc.; types of functional layered fabrics include but are not limited to woven fabrics, knitted fabrics, braided fabrics, non-woven fabrics, special fabrics, elastomers with buffering and vibration isolation functions, etc., and materials of functional layered fabrics include but are not limited to glass fiber, carbon fiber, metal film / fabric, ceramic material fabric, rubber, polyurethane and other elastomeric plastics, etc.

[0075] In summary, for materials that require different molding methods at different levels in composite material design, or multifunctional composite materials that cannot be molded in one go, the molding method in the embodiment of the present invention can achieve integrated molding of composite materials, while eliminating the problem of poor interface strength between different materials. At the same time, it is conducive to the functional superposition of the existing hollow fabric fleece layer, and to achieve highly integrated integrated molding preparation of different functional areas.

[0076] The molding method in the embodiment of the present invention will greatly enrich the organizational structure of the hollow fabric, improve the preparation efficiency of hollow fabrics with complex configurations and their composite materials, and effectively reduce production costs.

[0077] The embodiment of the present invention also provides a novel hollow fabric composite material, which is formed by any of the methods described above.

[0078] In order to more clearly illustrate the technical solution and advantages of the present invention, a novel hollow fabric forming tool and a method for forming a composite material thereof are described in detail below through several embodiments.

[0079] Embodiment 1:

[0080] First, follow the Figure 4 Design the Z-direction free yarn stitch distribution by:

[0081] In this embodiment, the free yarn is introduced three times, and one group of free yarn is introduced every three layers of fabric on the hollow fabric surface layer. The first nine layers are introduced three times in total (see the stitch design for each time). Figure 4 ), and the last layer of glass fiber cloth is laid separately for compounding.

[0082] In this embodiment, the Z-direction free yarn is designed as a "layer-like superposition" that runs through and interweaves the overall layered hollow fabric with different surface layer thickness levels, and is introduced multiple times according to the set thickness levels, thereby improving the surface layer's anti-failure ability and damage tolerance.

[0083] (1) Pre-designed hollow fabrics and their composite materials: New surface thickened hollow fabrics and their composite materials based on Z-direction free yarn system, with overall layup of: 200g / m 2 Glass fiber cloth*8 layers+functional layer*1 layer+200g / m 2 Glass fiber cloth*1 layer + 8mm hollow fabric. The functional layer design uses carbon fiber or metal fabric as the reflective layer.

[0084] (2) Determine the molding parameters of the molding tool: The molding tool includes: a fixed frame with a size of 300*300mm and a fixed core plate with a rectangular cross section and a height of 7.4mm; clean the foreign matter on the surface of the fixed frame and the fixed core plate, use alcohol to wipe the surface of the fixed core plate to ensure the surface is clean, and apply a release agent 3 to 4 times on the surface of the fixed core plate; the fabric body is a glass fiber fabric with a thickness of 8mm produced by Nanjing Glass Fiber Research and Design Institute Co., Ltd. (the pile warp height is 7.4mm, and the upper and lower layers are 0.3mm each);

[0085] (21) Insert 7.4 mm fixed core plates of the same height as the cavity along the velvet cavity channel of the 8 mm hollow fabric in sequence, and then place the fabric preform (hollow fabric + fixed core plate) as a whole on the fixed frame and use the limiting card slot to limit and fix it;

[0086] (22) According to the designed laying, the first layer of thick fabric (3 layers) is laid on the upper layer of the hollow fabric in sequence, and fixed at the edge to prevent slippage. Then, after marking and positioning according to the designed first layer of free yarn system stitches, the suture needle is introduced from top to bottom along the gap between the fixed core plates by manual sewing. The suture needle and thread pass through the first layer of thick fabric, the upper layer of the hollow fabric, the outer edge of the fixed core plate, and the lower layer of the hollow fabric in sequence. The yarn is distributed along the contour of the fixed core plate and connected to the upper and lower layers of fabric, forming a first layer of Z-direction free yarn system with a specific shape and distribution;

[0087] According to the designed laying, the second layer of thick fabric (3 layers) is laid on top of the first layer of thick fabric of the hollow fabric, and fixed at the edge to prevent slippage. Then, after marking and positioning according to the designed second layer of free yarn system stitches, the sewing needle is introduced from top to bottom along the gap between the fixed core plates by hand sewing. The sewing needle and thread pass through the second layer of thick fabric, the first layer of thick fabric, the upper layer of the hollow fabric, the outer edge of the fixed core plate, and the lower layer of the hollow fabric in turn. The yarn is distributed along the contour of the fixed core plate and connected to the upper and lower layers of fabric, forming a second layer of Z-direction free yarn system with a specific shape and distribution;

[0088] According to the designed laying, the third layer of thickness fabric (3 layers) is laid on top of the second layer of thickness fabric of the hollow fabric, and fixed at the edge to prevent slippage. Then, after marking and positioning according to the designed third layer of free yarn system stitches, the suture needle is introduced from top to bottom along the gap between the fixed core plates by manual suturing. The suture needle and thread are passed through the third layer of thickness fabric, the second layer of thickness fabric, the first layer of thickness fabric, the upper layer of the hollow fabric, the outer edge of the fixed core plate, and the lower layer of the hollow fabric in turn. The yarn is distributed along the contour of the fixed core plate and connected to the upper and lower layers of fabric, forming a third layer of Z-direction free yarn system with a specific shape and distribution;

[0089] According to the designed layer, a layer of 200g / m2 is laid on top of the third layer of hollow fabric. 2 Glass fiber fabric, and fix it at the edge to prevent it from slipping, to obtain a new type of hollow fabric;

[0090] (3) The fabric preform (hollow fabric + fixed core plate) is slowly removed from the fixed frame as a whole, and a vacuum bag is arranged on the outside of the fabric preform. The hollow fabric preform is fully infiltrated with resin using a vacuum drainage process, and heated and cured according to a preset process. After removing from the fixed core plate, a surface thickened hollow fabric composite material with different regional characteristics is obtained.

[0091] In Example 1, the samples before and after composite molding are as follows Figures 7 to 10 As shown, after testing, the surface thickness of the hollow fabric composite material is 2.7 mm, which is higher than the preset index (combined with the actual situation, the multi-layer superposition design of the thick fabric can be carried out according to the required surface layer thickness).

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A new type of hollow fabric forming tooling, characterized in that: It includes two fixed frames and a plurality of fixed core plates; wherein, a plurality of limit slots are provided on the two opposite side frames of each of the fixed frames, and the upper and lower ends of the fixed core plates are respectively fixed to each fixed frame through the limit slots, and the fixed core plates are used to fix the upper and lower layers and the core layer of the hollow fabric; there are gaps between adjacent fixed core plates.

2. The molding tool according to claim 1, characterized in that: The cross-sectional shape of the fixed core plate is at least one of square, rectangular, circular, elliptical or polygonal; The outer shape of the fixing frame is flat, curved or special-shaped.

3. The molding tool according to claim 1, characterized in that: The length of the fixed core plate is greater than the length of the fixed frame.

4. A method for forming a novel hollow fabric using a forming tool according to any one of claims 1 to 3, characterized in that: The method comprises: (1) determining the molding parameters of the molding tool according to the characteristic parameters of the pre-designed hollow fabric; wherein the characteristic parameters include the profile type, outer dimensions, cavity shape, cavity distribution and cavity density of the hollow fabric, and the molding parameters include the outer profile and dimensions of the fixed frame, and the dimensions, material and quantity of the fixed core plate; (2) according to the characteristic parameters of the pre-designed hollow fabric, the fabric body is fixedly formed by using the forming tool; wherein different fabric bodies correspond to different forming methods; (3) After molding, the fixed frames of the upper and lower layers of the hollow fabric are removed, and the hollow fabric preform is composite-molded by a resin composite molding process, and the novel hollow fabric composite material is obtained after removing the fixed core plate.

5. The method according to claim 4, characterized in that The profile types of the hollow fabric include flat type, curved type and special-shaped type; The material of the fixed core plate is determined based on the surface type of the hollow fabric; preferably, when the hollow fabric is planar, the fixed core plate is a rigid fixed core plate, and when the hollow fabric is curved, the fixed core plate is a flexible fixed core plate.

6. The method according to claim 4, characterized in that The fabric body comprises two fabric surface layers; The method of fixing and shaping the fabric by using the forming tool according to the pre-designed characteristic parameters of the hollow fabric comprises: Fix the fixed core plates to the fixed frame one by one through the limit slots according to the pre-designed cavity density and distribution; Laying the fabric surface layer in the upper and lower fixed frames respectively, so that the upper and lower surfaces formed by the plurality of fixed core plates are respectively in contact with the upper and lower layers of the fabric; According to the pre-designed pile warp distribution pattern, the yarn is introduced in sequence from top to bottom or from bottom to top along the gap between adjacent fixed core plates, so that the yarn is distributed along the contour of the fixed core plate and connects the upper and lower fabric layers to obtain the novel hollow fabric.

7. The method according to claim 4, characterized in that The fabric body is a hollow fabric, comprising an upper and lower surface layer and a core layer connected to the upper and lower surface layer, wherein the core layer is formed by evenly arranging a plurality of rows of pile warp layers, and a pile warp cavity is formed between adjacent pile warp layers; The method of fixing and shaping the fabric by using the forming tool according to the pre-designed characteristic parameters of the hollow fabric comprises: Inserting the fixed core plate between the pile warp cavities of the hollow fabric according to the pile warp cavity distribution of the hollow fabric, so that the upper and lower surfaces of the fixed core plate are completely in contact with the upper and lower layers of the hollow fabric, to obtain a fabric preform; A fixed frame is placed on the upper and lower surfaces of the fabric preform, and the fixed core plate is limited and fixed by using the limiting slots in the fixed frame; According to the pre-designed yarn distribution pattern, the yarn is introduced in sequence from top to bottom or from bottom to top along the gap between adjacent fixed core plates, so that the yarn is distributed along the contour of the fixed core plate and connects the upper and lower fabric layers to obtain the novel hollow fabric.

8. The method according to claim 6 or 7, characterized in that: Before fixing the fixed core plate by the limiting slot or inserting the fixed core plate along the hollow fabric pile cavity, the step of applying a release agent on the surface of the fixed core plate is also included.

9. The method according to claim 4, characterized in that Before placing the hollow fabric in step (2) in a molding tool for fixed molding, the method further includes laying a functional layer or a skin layer on the upper and lower surfaces of the fabric body.

10. A novel hollow fabric composite material, characterized in that: The method according to any one of claims 4 to 9 is used to form the product.

Images