A sandglass-shaped fabric of a combination structure and a method for manufacturing the same

Abstract

This invention provides a composite hourglass-shaped fabric and its preparation method. The hourglass-shaped fabric comprises at least two functional layers and a second functional layer fabric, which are stacked and connected from the inside to the outside. The first functional layer fabric is formed by splicing or overlapping at least a first functional layer first sub-region fabric and a first functional layer second sub-region fabric. The fabric structures of the first functional layer first sub-region fabric, the first functional layer second sub-region fabric, and the second functional layer fabric are selected from the same or different three-dimensional fabric structures. The materials of the first functional layer first sub-region fabric, the first functional layer second sub-region fabric, and the second functional layer fabric are the same or different. By adopting a composite structure design for different layers and different regions of the hourglass-shaped fabric, and using different fabric structures and materials for different layers and different regions, the adaptability of material performance to working conditions can be improved, achieving the functional optimization design of the hourglass-shaped product and the purpose of product weight reduction.

Description

Technical Field

[0001] This invention belongs to the field of fiber fabric technology, specifically relating to an hourglass-shaped fabric with a combined structure and its preparation method. Background Technology

[0002] Fiber-reinforced resin matrix composites possess high specific strength, high specific modulus, good impact resistance, and fatigue resistance. Compared to metal materials, their lower density allows for weight reduction, making them a viable alternative to metal materials as primary molding materials. Therefore, they are widely used in the aerospace field. Fiber-reinforced resin matrix composites are composed of reinforcing fibers and a resin matrix. The reinforcing fibers, using three-dimensional fabric preforms, possess excellent conformal molding capabilities, avoiding secondary processing, and exhibit better interlaminar bonding strength compared to multilayer fiber laminations and fiber windings.

[0003] Aerospace engine propulsion systems feature hourglass-shaped variable cross-section structures; therefore, the fabrication of their composite materials requires hourglass-shaped reinforcing fiber preforms. Currently, hourglass-shaped reinforcements are mostly fabricated using monolithic structures, such as three-dimensional woven structures and needle-punched structures. Chinese patent document CN 219028742 U discloses a variable-thickness hourglass-shaped preform, which is formed by multi-layer needle-punching of unit layers and finally reinforced through stitching. This reinforcement is fabricated monolithically using a needle-punched structure, resulting in a uniform structure and material throughout the reinforcement. This makes it impossible to adjust the structure and material of different regions of the reinforcement according to the actual application environment, leading to a low degree of performance mismatch between the reinforcement's performance and the application environment. Furthermore, the compressive strength of the frustum section 2 and column section regions in the hourglass-shaped reinforcement fabricated by this needle-punched structure is weaker than that of the three-dimensional woven structure, making it unsuitable for the fabrication of high-performance, large-size hourglass-shaped preforms. Chinese patent document CN 109914031 B discloses a method for preparing a three-dimensional high-pressure hourglass-shaped preform. The method uses a four-step three-dimensional multi-directional weaving process to weave and form the hourglass-shaped preform as a whole. The structure and material are consistent throughout the entire reinforcement. Similarly, the structure and material of different areas cannot be changed according to the requirements of the application environment. The performance of each area of ​​the reinforcement is poorly matched with the requirements of the application environment. Summary of the Invention

[0004] The technical problem solved by this invention is to provide a combined structure hourglass-shaped fabric and its preparation method. Different layers and regions of the hourglass-shaped fabric adopt a combined structure design, and different fabric structures and materials are used in different layers and regions. This can improve the adaptability of material performance to working conditions and environment, and achieve the purpose of functional optimization design and weight reduction of hourglass-shaped products.

[0005] To address the above problems, one aspect of the present invention provides an hourglass-shaped fabric with a combined structure, comprising:

[0006] The hourglass-shaped fabric comprises at least a first functional layer fabric and a second functional layer fabric stacked and connected from the inside to the outside; the first functional layer fabric and the second functional layer fabric are hourglass-shaped; the first functional layer fabric is at least spliced ​​or overlapped from a first functional layer first sub-region fabric and a first functional layer second sub-region fabric; the fabric structures of the first functional layer first sub-region fabric, the first functional layer second sub-region fabric, and the second functional layer fabric are selected from the same or different three-dimensional fabric structures; the materials of the first functional layer first sub-region fabric, the first functional layer second sub-region fabric, and the second functional layer fabric are the same or different.

[0007] Preferably, the first functional layer first sub-region fabric, the first functional layer second sub-region fabric, and the second functional layer fabric are made of one or more of the following: high silica fiber, quartz fiber, carbon fiber, silicon carbide fiber, and glass fiber.

[0008] Preferably, the first functional layer first sub-region fabric is located on the upper part of the first functional layer fabric, and the first functional layer second sub-region fabric is located on the lower part of the first functional layer fabric; the first functional layer first sub-region fabric includes a first frustum segment fabric, a column segment fabric and a second frustum segment fabric connected sequentially from top to bottom and integrally formed; the first functional layer second sub-region fabric includes a third frustum segment fabric, the top edge diameter of the third frustum segment fabric is the same as the bottom edge diameter of the second frustum segment fabric, and the taper of the third frustum segment fabric is the same as that of the second frustum segment fabric.

[0009] Preferably, the fabric structure of the first functional layer first sub-region fabric is one of a 2.5D structure, an orthogonal three-dimensional structure, and a three-dimensional braided structure; the fabric structure of the first functional layer second sub-region fabric is a needle-punched structure; the fabric structure of the second functional layer fabric is a needle-punched structure; the first functional layer first sub-region fabric and the first functional layer second sub-region fabric are connected by splicing needle punching or overlapping needle punching; the first functional layer fabric and the second functional layer fabric are connected by needle punching.

[0010] Preferably, the edge shape of the part of the first functional layer's first sub-region fabric that connects to the second functional layer fabric is stepped, inclined straight, or rectangular serrated.

[0011] Another aspect of the present invention provides a method for preparing an hourglass-shaped fabric with the above-described combined structure, comprising the following steps:

[0012] S1. Weave the fabric of the first functional layer in the first sub-region;

[0013] S2. Weave the second sub-region fabric of the first functional layer, and connect the second sub-region fabric of the first functional layer to the first sub-region fabric of the first functional layer by splicing or overlapping.

[0014] S3. Weave the second functional layer fabric and connect the second functional layer fabric to the first functional layer fabric;

[0015] S4. Using the outer surface of the second functional layer fabric as a reference, perform sewing operations in the normal direction to obtain the hourglass-shaped fabric of the combined structure.

[0016] Preferably, the first functional layer first sub-region fabric is located on the upper part of the first functional layer fabric; the first functional layer first sub-region fabric includes a first frustum segment fabric, a column segment fabric and a second frustum segment fabric that are connected sequentially from top to bottom and are integrally formed.

[0017] The method for weaving the first functional layer and the first sub-region fabric in step S1 specifically includes the following steps:

[0018] S1a. Warp yarns are arranged circumferentially along the mold; the mold includes a first frustum section, a column section, and a second frustum section connected in sequence.

[0019] S1b. The weft yarn is woven in the circumferential direction on the mold column segment, and the warp yarn is fixed so that the warp yarn and the weft yarn form an interlaced structure until the weaving of the column segment fabric is completed;

[0020] S1c. The weft yarn is woven in the circumferential direction on the first truncated section of the mold, the warp yarn is fixed, so that the warp yarn and the weft yarn form an interlaced structure, and the yarn is added according to the process requirements of the fabric of the first truncated section, until the weaving of the fabric of the first truncated section is completed.

[0021] S1d. On the second frustum section of the mold, the weft yarn is woven in the circumferential direction, the warp yarn is fixed, so that the warp yarn and the weft yarn form an interlaced structure, and the yarn is added according to the process requirements of the fabric of the second frustum section, until the weaving of the fabric of the second frustum section is completed.

[0022] S1f. Perform a sewing operation along the normal direction of the column segment fabric to obtain the first functional layer first sub-region fabric.

[0023] Preferably, step S2 specifically includes the following steps:

[0024] S2a. At the point where the first functional layer first sub-region fabric and the first functional layer second sub-region fabric are connected, the first functional layer first sub-region fabric is woven to form a connection joint.

[0025] S2b. Based on the completed connection, the connection and the second partition of the first functional layer are woven with a needle punch structure to obtain the fabric of the second sub-region of the first functional layer.

[0026] Preferably, step S3 specifically includes the following steps:

[0027] The second functional layer is woven in a needle-punched structure on the first functional layer first sub-region fabric and the first functional layer second sub-region fabric.

[0028] Preferably, the edge shape of the portion where the first functional layer's first sub-region fabric connects to the first functional layer's second sub-region fabric is stepped. In step S2a, the method for forming the connection joint of the first functional layer's first sub-region fabric is as follows: in the connection area, multiple layers of warp yarns on the outer or inner side of the first functional layer's first sub-region fabric are cut, and the remaining layers of the first functional layer's first sub-region fabric continue to be interwoven to form a stepped connection joint; or...

[0029] The edge shape of the portion where the first functional layer's first sub-region fabric connects to the first functional layer's second sub-region fabric is an inclined straight line. In step S2a, the method for forming the connection joint of the first functional layer's first sub-region fabric is as follows: In the connection area, for every weft woven in the first functional layer's first sub-region fabric, 1-2 layers of warp yarns are subtracted from the surface layer, and through multiple interlacing processes, an inclined straight line connection joint is formed; or...

[0030] The edge shape of the part where the first functional layer first sub-region fabric is connected to the first functional layer second sub-region fabric is rectangular serrated. In step S2a, the method of forming the connection joint of the first functional layer first sub-region fabric is as follows: in the connection area, the warp layers of the first functional layer first sub-region fabric are alternately cut and interwoven to form a rectangular serrated connection joint.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] The hourglass-shaped fabric of this invention employs a combined structural design, with different three-dimensional fabric structures and materials used for the inner and outer fabric layers and different areas of the fabric. The fabric structure and material can be selected to match the specific application scenario and working conditions of the hourglass-shaped fabric, taking into account the requirements for the ablation performance, mechanical properties, weight, and other aspects of the inner and outer fabrics, as well as different parts of the inner fabric. This improves the adaptability of the fabric performance to the application environment. Simultaneously, by functionally optimizing the fabric structure and material of each layer or area, low-density materials that meet the requirements of the working environment can be selected for each layer or area, achieving the goal of significantly reducing the weight while meeting performance requirements. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the hourglass-shaped fabric with the combined structure described in the embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the connection point in the hourglass-shaped fabric with the combined structure described in Embodiment 1 of the present invention;

[0035] Figure 3 This is a schematic diagram of the connection point in the hourglass-shaped fabric of the combined structure described in Embodiment 2 of the present invention;

[0036] Figure 4 This is a schematic diagram of the connection point in the hourglass-shaped fabric of the combined structure described in Embodiment 3 of the present invention;

[0037] Figure 5 This is a schematic diagram of the segmented trapezoidal structure of the longitudinal section of the hourglass-shaped fabric in the combined structure described in Embodiment 1 of the present invention.

[0038] Wherein: 1-First functional layer fabric; 11-First functional layer first sub-region fabric; 111-First frustum segment fabric; 112-Column segment fabric; 113-Second frustum segment fabric; 12-First functional layer second sub-region fabric; 2-Second functional layer fabric; 3-First sub-region; 4-Second sub-region; 5-Third sub-region; 6-Fourth sub-region. Detailed Implementation

[0039] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0040] One aspect of the present invention provides an hourglass-shaped fabric with a combined structure. The hourglass-shaped fabric includes at least a first functional layer fabric and a second functional layer fabric stacked and connected from the inside to the outside. The first functional layer fabric and the second functional layer fabric are hourglass-shaped. The first functional layer fabric is at least spliced ​​or overlapped with a first functional layer first sub-region fabric and a first functional layer second sub-region fabric. The fabric structures of the first functional layer first sub-region fabric, the first functional layer second sub-region fabric, and the second functional layer fabric are selected from the same or different three-dimensional fabric structures. The materials of the first functional layer first sub-region fabric, the first functional layer second sub-region fabric, and the second functional layer fabric are the same or different.

[0041] The hourglass-shaped fabric of this invention employs a combined structural design, comprising interconnected first and second functional layers from the inside out. The first functional layer is composed of first and second sub-regional fabrics located at different parts of the first functional layer, spliced ​​or overlapped. The inner and outer fabric layers use the same or different three-dimensional fabric structures and materials. The first and second sub-regional fabrics within the first functional layer also use the same or different three-dimensional fabric structures and materials. The fabric structure and material can be selected to match the specific application scenario and working conditions of the hourglass-shaped fabric, considering the requirements for the ablation performance, mechanical properties, weight, and other aspects of the inner and outer layers, as well as different parts of the inner layer, thereby improving the adaptability of the fabric performance to the application environment. Simultaneously, by functionally optimizing the fabric structure and material of each layer or region, low-density materials that meet the requirements of the working environment can be selected for each layer or region, achieving the goal of significantly reducing the weight while meeting performance requirements.

[0042] In some embodiments, the hourglass-shaped fabric may also include a third functional layer fabric, a fourth functional layer fabric, etc., which are stacked and connected from the inside to the outside.

[0043] In some embodiments, the first functional layer fabric may also include a third sub-region fabric of the first functional layer, a fourth sub-region fabric of the first functional layer, etc., and the first functional layer fabric is formed by splicing or overlapping the sub-region fabrics.

[0044] In some embodiments, the materials of the first functional layer's first sub-region fabric, the first functional layer's second sub-region fabric, and the second functional layer fabric are one or more of high-silica fibers, quartz fibers, carbon fibers, silicon carbide fibers, and glass fibers. The materials of the fabrics in different layers and regions are selected according to the specific application conditions of the hourglass-shaped fabric. For example, if the ablation performance of the first functional layer is required to be high, then the first functional layer can use one or more of the fibers selected from high-silica fibers, quartz fibers, carbon fibers, and silicon carbide fibers; the second functional layer can use high-performance fibers such as quartz fibers, high-silica fibers, and glass fibers.

[0045] In some embodiments, the first functional layer first sub-region fabric is located on the upper part of the first functional layer fabric, and the first functional layer second sub-region fabric is located on the lower part of the first functional layer fabric; the first functional layer first sub-region fabric includes a first frustum segment fabric, a column segment fabric and a second frustum segment fabric connected sequentially from top to bottom and integrally formed; the first functional layer second sub-region fabric includes a third frustum segment fabric, the top edge diameter of the third frustum segment fabric is the same as the bottom edge diameter of the second frustum segment fabric, and the taper of the third frustum segment fabric is the same as that of the second frustum segment fabric.

[0046] In some embodiments, the fabric structure of the first functional layer's first sub-region fabric is one of a 2.5D structure, an orthogonal triaxial structure, or a three-dimensional braided structure. For hourglass-shaped products, the first functional layer's first sub-region fabric, located at the top and containing two frustum segments and one column segment, experiences large ablation and interlayer shear. Therefore, a three-dimensional structure fabric is integrally molded and prepared. Based on the product's size and surface characteristics, a 2.5D structure, an orthogonal triaxial structure, or a three-dimensional braided structure is selected.

[0047] In some embodiments, the fabric structure of the second sub-region fabric of the first functional layer is a needle-punched structure; the fabric structure of the second functional layer fabric is a needle-punched structure; the first sub-region fabric of the first functional layer and the second sub-region fabric of the first functional layer are connected by splicing needle punching or overlapping needle punching; the first functional layer fabric and the second functional layer fabric are connected by needle punching.

[0048] In some embodiments, the edge shape of the portion of the first functional layer's first sub-region fabric that connects to the second functional layer's second sub-region fabric is stepped, inclined straight, or rectangular serrated.

[0049] Another aspect of the present invention provides a method for preparing an hourglass-shaped fabric with the above-described combined structure, comprising the following steps:

[0050] S1. Weave the first functional layer, first sub-region fabric;

[0051] S2. Weave the second sub-region fabric of the first functional layer, and connect the second sub-region fabric of the first functional layer to the first sub-region fabric of the first functional layer by splicing or overlapping.

[0052] S3. Weave the second functional layer fabric and connect the second functional layer fabric to the first functional layer fabric;

[0053] S4. Using the outer surface of the second functional layer fabric as a reference, perform sewing operations in the normal direction to obtain an hourglass-shaped fabric with a combined structure.

[0054] The method for preparing the hourglass-shaped fabric with the combined structure in this embodiment improves the material performance and adaptability to the working environment by using different fabric structures and materials for different layers and regions of the hourglass-shaped fabric through combined structure design. By optimizing the fabric structure and material of each layer or region, each layer or region can also select low-density materials that meet the requirements of the working environment, so as to achieve the goal of greatly reducing the weight while meeting the performance requirements of the product.

[0055] In some embodiments, the first functional layer first sub-region fabric is located on the upper part of the first functional layer fabric; the first functional layer first sub-region fabric includes a first frustum segment fabric, a column segment fabric and a second frustum segment fabric that are connected sequentially from top to bottom and are integrally formed.

[0056] The method for weaving the first functional layer and the first sub-region fabric in step S1 specifically includes the following steps:

[0057] S1a. Warp yarns are arranged circumferentially along the mold; the mold includes a first frustum section, a column section, and a second frustum section connected in sequence.

[0058] S1b. Weft yarns are woven in the circumferential direction on the mold column section to fix the warp yarns, so that the warp yarns and weft yarns form an interlaced structure until the weaving of the column section fabric is completed;

[0059] S1c. Weft yarns are woven in the circumferential direction on the first truncated cone section of the mold, the warp yarns are fixed, so that the warp yarns and weft yarns form an interlaced structure, and yarn addition is performed according to the process requirements of the fabric of the first truncated cone section until the weaving of the fabric of the first truncated cone section is completed.

[0060] S1d. On the second truncated cone section of the mold, the weft yarn is woven in the circumferential direction, the warp yarn is fixed, so that the warp yarn and the weft yarn form an interlaced structure, and the yarn is added according to the process requirements of the fabric of the second truncated cone section until the weaving of the fabric of the second truncated cone section is completed.

[0061] S1f. Perform sewing along the normal of the column segment fabric to obtain the first functional layer first sub-region fabric.

[0062] The method for preparing the hourglass-shaped fabric with the combined structure in this embodiment involves weaving the first functional layer of the hourglass-shaped fabric into the first sub-region starting from the column segment with the smallest diameter. The column segment in the middle is woven first, and then the diameter of the truncated cone segment gradually increases from the middle to both ends by adding yarn. This eliminates the need to reduce yarn during the diameter change process in the truncated cone segment, avoiding defects such as continuous gaps and holes in local areas inside the preform after yarn reduction. This ensures the continuity of the fiber structure and the uniformity of warp and weft density of the entire fabric, and reduces the difficulty of its weaving process.

[0063] Preferably, in step S1b, when weaving the mold column segment using weft yarn in the circumferential direction, the yarn is divided into sub-regions in the thickness direction of the first functional layer's first sub-region fabric for weaving. The weaving length of each sub-region is controlled, and the weaving length of each sub-region gradually decreases from the inner side to the outer side of the first functional layer's first sub-region fabric, forming a trapezoidal column segment fabric with a stepped oblique side in the longitudinal section. The method for preparing the hourglass-shaped fabric with the combined structure of this embodiment of the invention involves sub-regional weaving in the column segment. By controlling the weaving length of each sub-region, a trapezoidal column segment fabric with a stepped oblique side is formed. The stepped oblique side can serve as the basis for weft winding towards the frustum segment. Since weft winding is carried out layer by layer from the inner side of the fabric to the outer side, the oblique side, which is shorter on the outside and longer on the inside, makes it easier to start the weft winding operation from the inside, thereby facilitating the weaving production of the first frustum segment fabric and the second frustum segment fabric and reducing the difficulty of its weaving process.

[0064] In some implementations, step S2 specifically includes the following steps:

[0065] S2a. At the junction of the first functional layer first sub-region fabric and the first functional layer second sub-region fabric, the first functional layer first sub-region fabric is woven to form a joint.

[0066] S2b. Based on the completed connection, the connection and the second section of the first functional layer are woven with a needle punch structure to obtain the fabric of the second sub-region of the first functional layer.

[0067] In some embodiments, the edge shape of the part where the first functional layer first sub-region fabric is connected to the second functional layer fabric is stepped. In step S2a, the method of forming the connection joint of the first functional layer first sub-region fabric is as follows: in the connection area, multiple layers of warp yarns on the outer or inner side of the first functional layer first sub-region fabric are cut, and the remaining layers of the first functional layer first sub-region fabric are continued to be interwoven to form a stepped connection joint.

[0068] In some embodiments, the edge shape of the part where the first functional layer first sub-region fabric is connected to the first functional layer second sub-region fabric is an inclined straight line. In step S2a, the method of forming the connection joint of the first functional layer first sub-region fabric is as follows: in the connection area, the first functional layer first sub-region fabric is weaving 1-2 layers of warp yarns on the surface layer for every 1 weft of the first functional layer first sub-region fabric, and after multiple interlacing, an inclined straight line connection joint is formed.

[0069] In some embodiments, the edge shape of the part where the first functional layer first sub-region fabric is connected to the second functional layer fabric is rectangular serrated. In step S2a, the method of forming the connection joint of the first functional layer first sub-region fabric is as follows: in the connection area, the warp layers of the first functional layer first sub-region fabric are alternately cut and interwoven to form a rectangular serrated connection joint.

[0070] By adopting the above-mentioned overlapping structure design, the interlacing area of ​​the yarn in the first functional layer first sub-region fabric is controlled to realize the surface weaving of the connection port. Then, the connection port fabric of the first functional layer first sub-region fabric and the first functional layer second sub-region fabric are connected layer by layer by needle punching structure to form an integral structure, thereby effectively connecting the first functional layer first sub-region fabric and the first functional layer second sub-region fabric.

[0071] In some implementations, step S3 specifically includes the following steps:

[0072] The second functional layer is woven in a needle-punched structure on the first functional layer first sub-region fabric and the first functional layer second sub-region fabric.

[0073] Example 1

[0074] The hourglass-shaped fabric of this embodiment is a carbon fiber / quartz fiber composite fabric with a thickness of 20 mm and a total height of 500 mm.

[0075] like Figure 1 As shown, the hourglass-shaped fabric of this embodiment comprises, from the inside to the outside, a first functional layer fabric 1 and a second functional layer fabric 2, which are stacked and connected. The first functional layer fabric 1 and the second functional layer fabric 2 are hourglass-shaped. The first functional layer fabric 1 is formed by splicing or overlapping the first functional layer first sub-region fabric 11 and the first functional layer second sub-region fabric 12. The first functional layer first sub-region fabric 11 is located at the upper part of the first functional layer fabric 1, and the first functional layer second sub-region fabric 12 is located at the lower part of the first functional layer fabric 1. The first functional layer first sub-region fabric 11 includes a first frustum segment fabric 111, a column segment fabric 112, and a second frustum segment fabric 113, which are connected sequentially from top to bottom and are integral. The first functional layer second sub-region fabric 12 includes a third frustum segment fabric, the top edge diameter of which is the same as the bottom edge diameter of the second frustum segment fabric 113, and the taper of the third frustum segment fabric is the same as that of the second frustum segment fabric 113. The edge shape of the part where the first functional layer's first sub-region fabric 11 connects to the first functional layer's second sub-region fabric 12 is stepped. The dimensional parameters and fabric process parameters of each layer and sub-region are designed as shown in Table 1.

[0076] Table 1

[0077]

[0078] The first functional layer first sub-region fabric 11 is made of carbon fiber; the first functional layer second sub-region fabric 12 is made of carbon cloth + mesh; and the second functional layer fabric 2 is made of quartz cloth + mesh. The fabric structure of the first functional layer first sub-region fabric 11 is a 2.5D structure, or an orthogonal three-dimensional structure or a three-dimensional weaving structure can also be used; the first functional layer second sub-region fabric 12 and the second functional layer fabric 2 both use a needle-punched structure.

[0079] The method for preparing the hourglass-shaped fabric with the combined structure in this embodiment includes the following steps:

[0080] S1. Utilize a 2.5D structure to weave the first functional layer and the first sub-region fabric:

[0081] S1a. Install the hourglass-shaped mold onto the weaving platform. Calculate the outer perimeter of the columnar fabric and the fabric parameters. The outer perimeter of the columnar fabric is 264mm, the warp density is 6 warp threads / cm, the number of warp layers is 10, and the number of warp threads is 26.4×6×10=1584. Arrange the warp threads circumferentially along the mold and fix them to the mold using tooling. The mold includes a first frustum section, a columnar section, and a second frustum section connected in sequence.

[0082] S1b. Divide the N=10 warp layers into 4 sub-areas for weaving, using 2 layers, 3 layers, 3 layers, and 2 layers of warp yarns as each weaving area. Figure 5 As shown; on the mold column section, the 2.5D weaving method is used to fix the warp yarns by wrapping them around the weft yarns in the circumferential direction, and the first sub-region 3 is woven. The two layers of warp and weft yarns in the first sub-region 3 are interwoven. The value of X is calculated from the length of the main direction of the column section fabric and the warp density. The number of interweaving times X = 10 × 1.5 = 15 times, and the weaving of the innermost first sub-region 3 is completed. The fabric completely covers the mold column section. The above operation is repeated. On the innermost first sub-region 3, the second sub-region 4, the third sub-region 5, and the fourth sub-region 6 are woven in sequence. In the second sub-region 4, the three layers of warp and weft yarns are interwoven using a 2.5D weaving method, with the number of interweavings X = 15 - 2 × 2 = 11 times (the first sub-region 3 is woven 2 times less at both ends). The warp yarns are fixed in the column section area along the circumferential direction. After the second sub-region 4 is woven, the above operation is repeated. In the third sub-region 5, the three layers of warp and weft yarns are interwoven using a 2.5D weaving method, with the number of interweavings X = 11 - 2 × 2 = 7 times (the second sub-region 4 is woven 2 times less at both ends). The warp yarns are fixed in the column section area along the circumferential direction. After the third sub-region 5 is woven, the above operation is repeated. In the fourth sub-region 6, the two layers of warp and weft yarns are interwoven using a 2.5D weaving method, with the number of interweavings X = 7 - 2 × 2 = 3 times (the third sub-region 5 is woven 2 times less at both ends). The warp yarns are fixed in the column section area along the circumferential direction. After weaving, the column section fabric forms a trapezoidal column section fabric with a stepped oblique side in the longitudinal section, as shown below. Figure 2 As shown;

[0083] S1c. On the first truncated cone section of the upper mold, the 10 layers of warp yarns fixed to the surface of the mold column section are arranged in a "row" and "column" structure to ensure that the warp yarns at the slope are not obviously intertwined; on the first truncated cone section of the upper mold, the 10 layers of warp yarns are layered and interlaced in a 2.5D structure, and the weft yarns are wound around the effective opening in the circumferential direction. The weft yarns are based on the stepped oblique side of the trapezoidal column section fabric and are wound and fixed on the fabric for weaving; through the warp yarn addition process, the warp yarn rows are added to the truncated cone section fabric 111 according to the process requirements, so that the diameter of the truncated cone section fabric 111 continuously increases until the weaving of the truncated cone section fabric 111 is completed;

[0084] S1d. On the second frustum section of the mold on the lower side of the mold, the 10 layers of warp yarns fixed on the surface of the mold column section are arranged in a "row" and "column" structure to ensure that the warp yarns at the slope are not obviously intertwined; on the second frustum section of the mold on the lower side of the mold, the 10 layers of warp yarns are layered and interlaced in a 2.5D structure, and the weft yarns are wound around the fabric in the circumferential direction in the effective opening formed. The weft yarns are based on the stepped oblique side of the trapezoidal column section fabric and are wound and fixed on the fabric for weaving; through the warp yarn addition process, the warp yarn rows are added to the frustum section fabric 113 according to the process requirements, so that the diameter of the frustum section fabric 113 continuously increases until the weaving of the frustum section fabric 113 is completed.

[0085] S1f. Using a stitching structure, stitches are made in the normal direction of the column segment fabric, with a stitch spacing of 15±2mm and a stitch row spacing of 15±2mm, to obtain the first functional layer first sub-region fabric.

[0086] S2. Weave the fabric of the second sub-region of the first functional layer, and connect the fabric of the second sub-region of the first functional layer to the fabric of the first sub-region of the first functional layer by splicing or overlapping:

[0087] S2a. The design connection length is 40mm. The carbon fiber fabric of the first functional layer first sub-region fabric is designed to overlap and form a joint. In the 40mm connection area, the outer 6-10 layers of warp yarns of the fabric are cut, and the inner 1-5 layers of warp yarns are interwoven for 40mm to form a stepped connection.

[0088] S2b. Based on the completed connection, needle-punching is performed on the connection and the second section of the first functional layer to obtain the second sub-region fabric of the first functional layer. Splicing needle-punching is performed on the inner 1-5 layers of the frustum section of the first sub-region fabric 11 and the second sub-region fabric 12 of the first functional layer, and overlapping needle-punching is performed on the outer 6-10 layers of the first sub-region fabric 11 and the second sub-region fabric 12 of the first functional layer, forming a continuous, equal-length overlapping structure in the thickness direction.

[0089] S3. Based on the combined fabric of the first functional layer first sub-region fabric 11 and the first functional layer second sub-region fabric 12 that have been overlapped and needle-punched, 10mm quartz needle-punched fabric is prepared to form a carbon fiber / quartz fiber combined fabric.

[0090] S4. Based on the outer side of the already needle-punched carbon fiber / quartz composite fabric, with a stitch distance of 10±2mm and a stitch row spacing of 10±2mm as parameters, perform stitching operations in the normal direction of the composite fabric to obtain an hourglass-shaped fabric with a composite structure.

[0091] Example 2

[0092] The hourglass-shaped fabric of the combined structure in this embodiment is a carbon fiber / quartz fiber combined structure fabric. The rest of the structure is the same as that in Embodiment 1. The difference is that the edge shape of the part where the first functional layer first sub-region fabric 11 is connected to the first functional layer second sub-region fabric 12 is an inclined straight line.

[0093] In the preparation method of the hourglass-shaped fabric with the combined structure in this embodiment, the remaining steps are the same as in Example 1, except that:

[0094] S2a. The design joint length is 40mm. An overlap molding design is implemented on the carbon fiber fabric of the first functional layer, first sub-region. In the 40mm joint area, 1-2 layers of warp yarns are subtracted from the surface layer for every weft woven. After multiple interlacing processes, an inclined straight joint is formed. Figure 3 As shown;

[0095] S2b. Based on the completed connection, needle-punching is performed on the connection and the second section of the first functional layer to obtain the second sub-region fabric of the first functional layer. Splicing needle-punching is performed on layers 1-10 of the frustum section of the first sub-region fabric 11 and the second sub-region fabric 12 of the first functional layer to form a continuous overlapping structure of different lengths in the thickness direction.

[0096] Example 3

[0097] The hourglass-shaped fabric of the combined structure in this embodiment is a carbon fiber / quartz fiber combined structure fabric. The rest of the structure is the same as that in embodiment 1. The difference is that the edge shape of the part where the first functional layer first sub-region fabric 11 is connected to the first functional layer second sub-region fabric 12 is rectangular serrated.

[0098] In the preparation method of the hourglass-shaped fabric with the combined structure in this embodiment, the remaining steps are the same as in Example 1, except that:

[0099] S2a. The design joint length is 40mm. The carbon fiber fabric of the first functional layer, first sub-region, is designed with an overlapping joint. In the 40mm joint area, the warp yarns of the even-numbered layers (2, 4, 6, 8, 10 layers) are cut, and the odd-numbered layers (1, 3, 5, 7, 9 layers) continue to interweave for 40mm according to a single-layer structure, forming a rectangular sawtooth joint. Figure 4 As shown;

[0100] S2b. Based on the completed connection, needle-punching is performed on the connection and the second section of the first functional layer to obtain the second sub-region fabric of the first functional layer. Splicing needle-punching is performed on the odd-numbered layers (1, 3, 5, 7, 9 layers) of the first sub-region fabric 11 and the second sub-region fabric 12 of the first functional layer, and overlapping needle-punching is performed on the even-numbered layers (2, 4, 6, 8, 10 layers) of the first sub-region fabric 11 and the second sub-region fabric 12 of the first functional layer, forming an overlapping structure with equal intervals in the thickness direction.

[0101] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An hourglass-shaped fabric with a composite structure, characterized in that: The hourglass-shaped fabric comprises, from the inside to the outside, at least a first functional layer fabric and a second functional layer fabric stacked and connected; the first functional layer fabric and the second functional layer fabric are hourglass-shaped; the first functional layer fabric is formed by splicing or overlapping needle punching of the first functional layer first sub-region fabric and the first functional layer second sub-region fabric; the fabric structures of the first functional layer first sub-region fabric, the first functional layer second sub-region fabric, and the second functional layer fabric are selected from the same or different three-dimensional fabric structures; the materials of the first functional layer first sub-region fabric, the first functional layer second sub-region fabric, and the second functional layer fabric are the same or different; the first functional layer first sub-region fabric is located on the upper part of the first functional layer fabric; the first functional layer first sub-region fabric includes a first frustum segment fabric, a column segment fabric, and a second frustum segment fabric connected sequentially from top to bottom and integrally formed. The method for preparing the hourglass-shaped fabric with the combined structure includes the following steps: S1. Weave the fabric of the first functional layer in the first sub-region; S2. Weave the second sub-region fabric of the first functional layer, and connect the second sub-region fabric of the first functional layer to the first sub-region fabric of the first functional layer by splicing needle punching or overlapping needle punching. S3. Weave the second functional layer fabric and connect the second functional layer fabric to the first functional layer fabric; S4. Using the outer surface of the second functional layer fabric as a reference, perform sewing operations in the normal direction to obtain the hourglass-shaped fabric of the combined structure; The method for weaving the first functional layer and the first sub-region fabric in step S1 specifically includes the following steps: S1a. Warp yarns are arranged circumferentially along the mold; the mold includes a first frustum section, a column section, and a second frustum section connected in sequence. S1b. The weft yarn is woven in the circumferential direction on the mold column segment, and the warp yarn is fixed so that the warp yarn and the weft yarn form an interlaced structure until the weaving of the column segment fabric is completed; S1c. The weft yarn is woven in the circumferential direction on the first truncated section of the mold, the warp yarn is fixed, so that the warp yarn and the weft yarn form an interlaced structure, and the yarn is added according to the process requirements of the fabric of the first truncated section, until the weaving of the fabric of the first truncated section is completed. S1d. On the second frustum section of the mold, the weft yarn is woven in the circumferential direction, the warp yarn is fixed, so that the warp yarn and the weft yarn form an interlaced structure, and the yarn is added according to the process requirements of the fabric of the second frustum section, until the weaving of the fabric of the second frustum section is completed. S1f. Perform sewing along the normal of the column segment fabric to obtain the first functional layer first sub-region fabric; Step S2 specifically includes the following steps: S2a. At the point where the first functional layer first sub-region fabric and the first functional layer second sub-region fabric are connected, the first functional layer first sub-region fabric is woven to form a connection joint. S2b. Based on the completed connection point, the connection point and the second sub-area fabric of the first functional layer are connected by a needle punch structure; The edge shape of the part where the first functional layer's first sub-region fabric connects to the first functional layer's second sub-region fabric is stepped. In step S2a, the method for forming the connection joint of the first functional layer's first sub-region fabric is as follows: in the connection area, multiple layers of warp yarns on the outer or inner side of the first functional layer's first sub-region fabric are cut, and the remaining layers of the first functional layer's first sub-region fabric continue to be interwoven to form a stepped connection joint; or, The edge shape of the portion where the first functional layer's first sub-region fabric connects to the first functional layer's second sub-region fabric is an inclined straight line. In step S2a, the method for forming the connection joint of the first functional layer's first sub-region fabric is as follows: In the connection area, for every weft woven in the first functional layer's first sub-region fabric, 1-2 layers of warp yarns are subtracted from the surface layer, and through multiple interlacing processes, an inclined straight line connection joint is formed; or... The edge shape of the part where the first functional layer first sub-region fabric is connected to the first functional layer second sub-region fabric is rectangular serrated. In step S2a, the method of forming the connection joint of the first functional layer first sub-region fabric is as follows: in the connection area, the warp layers of the first functional layer first sub-region fabric are alternately cut and interwoven to form a rectangular serrated connection joint.

2. The hourglass-shaped fabric with the combined structure according to claim 1, characterized in that: The first functional layer first sub-region fabric, the first functional layer second sub-region fabric, and the second functional layer fabric are made of one or more of the following: high silica fiber, quartz fiber, carbon fiber, silicon carbide fiber, and glass fiber.

3. The hourglass-shaped fabric with the combined structure according to claim 1, characterized in that: The second sub-region fabric of the first functional layer includes a third frustum section fabric, the top edge diameter of the third frustum section fabric is the same as the bottom edge diameter of the second frustum section fabric, and the taper of the third frustum section fabric is the same as that of the second frustum section fabric.

4. The hourglass-shaped fabric with the combined structure according to claim 3, characterized in that: The fabric structure of the first functional layer first sub-region fabric is a three-dimensional woven structure; the fabric structure of the first functional layer second sub-region fabric is a needle-punched structure; the fabric structure of the second functional layer fabric is a needle-punched structure; the first functional layer fabric and the second functional layer fabric are connected by needle punching.

5. The hourglass-shaped fabric with the combined structure according to claim 1, characterized in that: Step S3 specifically includes the following steps: The second functional layer fabric is woven in a needle-punched structure on the first functional layer first sub-region fabric and the first functional layer second sub-region fabric.

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