CN102560808A - Weaving method of high-strength woven hollow-core reinforcer - Google Patents

Abstract

Disclosed is a forming method of a woven hollow-core reinforcer with the surface layer having multilayer structure. During weaving of the woven hollow-core reinforcer, a core portion is woven into a knotted warp hollow core which connects the upper surface layer and the lower surface layer. Meanwhile, the upper surface layer and the lower surface layer are woven into multiple fabric layers connected with a knotted warp attaching layer. The structure with multiple fabric layers parallel to each other includes that one or more groups of knotted warps of the surface layers run through vertically in the range of the upper surface layer or the lower surface layer in a slow warp feeding speed, and aims to densely connect the multiple fabric layers into the upper layer or the lower layer with a certain thickness and multiple knotted structure. To the core portion between the upper surface layer and the lower surface layer, the inner layers of the upper surface layer and the lower surface layer are connected by another one or more groups of knotted warps of the core portion in a faster warp feeding speed, so that the upper surface layer and the lower surface layer with multiple fabric layers are connected to form an integral spaced hollow-core structure integrally.

Description

A Weaving Method of High Strength Woven Hollow Reinforcement

Technical field

The invention relates to a method for forming a woven hollow reinforcement, in particular to a method for forming a woven hollow reinforcement whose surface layer is multi-layered.

Background technique

Hollow-core woven fabric is a three-dimensional structure of textiles. It is usually used to form a hollow-core structure composite material after being compounded with resin. It is often used as a lightweight load-bearing structural material. It is applied in the field of composite materials and can complete the composite molding with the resin matrix at one time, which not only simplifies the post-processing technology of composite materials, but also reduces the production cost, and the upper and lower surface layers of this structural material are jointly connected by joints and resin. , has a certain overall height, so it can improve the interlaminar shear resistance of the composite material. Such fabrics have been the subject of research due to their good overall mechanical properties when used as reinforcements.

At present, the formation method of the known woven hollow reinforcement is that the warp and weft yarns of the upper and lower systems are respectively interwoven to form the upper and lower layers of the single-layer structure of the fabric, and the binding warps appear in the upper and lower layers of the fabric in turn with a certain rule, and the fabric The upper and lower layers are connected to form a whole hollow structure.

For example, in the patent CN2863826 (a kind of glass fiber integral spacer woven fabric), a hollow woven fabric for FRP with a relatively large hollow core height and a certain density is proposed, which is characterized in that there are connecting warps in the middle of the fabric to form a pair The "W"-shaped hollow connection of the left fabric and the right fabric.

In the patent CN1297073 (hollow laminated fabric composite material), a composite material with a woven fabric as a skeleton is proposed. The composite material skeleton is formed by interweaving warp and weft yarns of the upper layer fabric to form the upper layer of the fabric; The upper and lower fabrics are connected as a whole fabric.

The above two patents have a common disadvantage, that is, the formed surface layer is a single-layer fabric structure, and the bending resistance is relatively poor. Because under the action of bending stress, the stress gradually decreases from the upper and lower surfaces of the material to the neutral layer, while the upper and lower surfaces of the material bear greater stress, which limits the fabric with a single layer of surface layer. The improvement of the mechanical properties of the fabric and the expansion of the application fields of the fabric and its composite materials are affected.

How to improve the flexural strength of hollow-core woven fabrics and their composite materials has become a research topic in production.

As plates and beams of various shapes, such as laminated panels and hollow sandwich panels are widely used in engineering structural materials, such as rectangular, T-shaped, I-shaped, ∏-shaped (multi-purpose for railway bridges) and box-shaped cross-section beams. etc., there are higher requirements for various mechanical strengths, such as tensile strength and bending strength.

According to the mechanics of materials, in general, the flexural strength of a material is positively correlated with other strengths. Therefore, the research and discussion on the improvement of the mechanical properties of materials can be represented by the flexural strength, which is consistent with the use status of many components and products, especially plates, which are usually subjected to bending stress during use.

How to continuously improve the mechanical properties of plate materials or profiles has always been the pursuit of material design, production and research, and some technical solutions for this have also emerged.

For example, in the patent CN1038613 (manufacturing method of high bending strength light body core board), a kind of manufacturing method that can be made into a large-scale board in advance is proposed. Materials such as ribs and nets are subjected to hot pressing or cold pressing to improve the bending strength.

In the patent CN1289285 (laminated phenolic resin foam board and its manufacturing method), a kind of longitudinal bending elastic modulus and bending strength are provided, and the phenolic resin foam laminated board and its suitable flexibility are improved. The production method is achieved by stretching the striped foam passing through the conveyor by 4-12% in the forward direction of the complete curing front, and this stretching itself improves the mechanical properties of the material.

In the patent CN1344602 (bending structure of bamboo (wood) plate), a kind of bending structure of bamboo (wood) plate is provided, and the method is to achieve of.

From the above patents and production practice, it can be seen that the improvement of the flexural strength is not only related to the performance of the material itself, but also related to the cross-section or the spatial distribution of the material.

In actual production, in order to improve the mechanical strength of the hollow woven fabric such as bending resistance, the commonly used improvement method is to combine the fabric with resin on the upper and lower surfaces of the hollow woven fabric with a single-layer fabric structure. During the forming process, one or more layers of fabric of ordinary structure are laminated to thicken the surface tissue. However, the disadvantage of this method is that the laminated product is prone to tearing and delamination during subsequent processing or use, which affects the overall performance and service life of the final material.

Contents of the invention

In order to overcome the deficiency that the upper and lower surface layers of the existing hollow-core woven fabrics are single-layer structures, which affect the bending resistance of this type of fabric-reinforced composite material, or, in order to overcome the upper and lower surface layers of the existing hollow-core woven materials As a laminated structure, it is easy to cause tearing and delamination damage. The invention provides a method for forming a woven hollow core integral structure with a surface layer of multi-layer structure. The thickness of the upper and lower surface layers of the fabric formed by the method is increased, thereby improving the mechanical properties of the fabric, especially the mechanical properties of the final composite material.

The technical scheme adopted by the present invention to solve the technical problem is: in the weaving process of the woven hollow reinforcement, the number of layers of the upper and lower surface layers of the fabric is increased. That is to say, whether it is the upper surface layer or the lower surface layer, the warp and weft yarns of two or more systems are interwoven to form a fabric structure with several layers parallel to each other, and, in the entire weaving cycle, these layers are parallel to each other. The fabric structure consists of one or more sets of surface binding warps that move up and down on the upper or lower surface at a slower let-off speed, in order to tightly connect these layers of fabrics into a structurally multi-layered joint. The upper or lower surface of the tissue with a certain overall thickness; at the same time, for the core between the upper surface and the lower surface, another group or more groups of cores are bound by a faster let-off speed The inner layer of the upper and lower surface layers is connected, and the upper and lower two surface layers that have formed a multi-layer structure are connected to form a whole hollow core structure in a spaced state.

其中，M_max为最大弯矩，W称为截面图形的抗弯截面模量，W只与截面图形的几何性质有关。对于高为h，宽为b的矩形截面，抗弯截面模量

因此可知，当材料所受最大弯矩M_max不变时，材料的高度h越大，抗弯截面模量就W越大，截面上所受最大正应力σ_max越小，也就提高了结构材料的抗弯强度。由此也可以看出，在外边缘达到许用应力时，中性轴附近的应力很小，为尽可能地避免材料的使用造成浪费，材料在结构设计时应尽可能往“上、下”分布，以增大高h。例如，对具有一定高度的矩形截面的板或梁来说，理想的情况是，将面积之半分布于距中性轴为h/2处，在结构上对中性轴距离越小处，耗用材料应越少。整体空芯板正是符合该设计原则。而本发明的解决其技术问题所采用的增加织物上下表层的层数的技术方案也正是该设计原则的进一步的运用。The technical solution adopted by the present invention to solve its technical problems is based on the theory of material mechanics (discussing as a representative of the performance index with the flexural strength): rationally designing and optimizing the cross-sectional shape of the material to increase the flexural section modulus is An important measure to improve the bending strength. Because the maximum normal stress on the cross-section of the structural material

Among them, M _max is the maximum bending moment, W is called the flexural section modulus of the cross-sectional figure, and W is only related to the geometric properties of the cross-sectional figure. For a rectangular section with height h and width b, the flexural section modulus

Therefore, it can be seen that when the maximum bending moment M _max of the material is constant, the greater the height h of the material, the greater the flexural section modulus W, and the smaller the maximum normal stress σ _max on the section, which improves the structure. The flexural strength of the material. It can also be seen from this that when the outer edge reaches the allowable stress, the stress near the neutral axis is very small. In order to avoid material waste as much as possible, the material should be distributed as "up and down" as possible in the structural design , to increase the height h. For example, for a plate or beam with a rectangular section with a certain height, the ideal situation is to distribute half of the area at a distance of h/2 from the neutral axis, and the smaller the distance to the neutral axis in the structure, the less energy consumption Use less material. The overall hollow core board is in line with this design principle. And the technical scheme of increasing the number of layers of the upper and lower surface layers of the fabric adopted to solve the technical problems of the present invention is also the further application of this design principle.

The realization of the technical solution adopted by the present invention to solve its technical problems in textile technology is: by the above-mentioned technical solution of the present invention, it can be known that the surface layer is to be made into a fabric with a woven hollow core structure of a multi-layer structure, and the loom Two basic conditions must be met, one is the layered weaving technology with multi-heald frames, and the other is multi-axis or multi-speed warp let-off technology. However, in terms of mechanical structure and function, the current woven looms have the ability to completely A proven technology that meets these two basic conditions required.

The beneficial effect of the present invention is that it provides a method for forming a woven hollow structure whose surface layer is a multilayer structure, which increases the thickness of the fabric surface layer and improves the resistance of the fabric and its final product after it is compounded with other materials. The physical and mechanical properties such as bending and impact resistance have expanded the scope of its application field, especially helping its development to the industrial field.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is a schematic diagram of the fabric structure of Embodiment 1 of the method of the present invention.

Fig. 2 is a longitudinal cross-sectional view of the fabric structure of Embodiment 1 of the method of the present invention.

Fig. 3 is a diagram of the trajectory of each warp yarn in Embodiment 1 of the method of the present invention.

Fig. 4 is a weaving process diagram of the fabric of Embodiment 1 of the method of the present invention on a dobby loom.

Fig. 5 is a longitudinal sectional view of the woven hollow reinforcement body according to the second embodiment of the method of the present invention.

Fig. 6 is a longitudinal cross-sectional view of the woven hollow reinforcement body according to the third embodiment of the method of the present invention.

Among the figure 1, 2, 3, 10, 11, 12 are upper surface layer warp yarns; 4, 5, 6, 13, 14, 15 are lower surface layer warp yarns; 7, 16 are upper surface layer connecting warp yarns; 8, 17 are The lower surface layer connects warp yarns; 9 and 18 are empty core spaced connecting warp yarns; A is the upper surface layer structure; C is the lower surface layer structure; B is the core structure.

Detailed ways

Embodiment one:

Fig. 1 is a schematic diagram of the fabric structure of the first embodiment of the method of the present invention. The fabric is composed of three parts in structure, one is the upper surface structure A, which is closely connected by three layers of tissue; the other is the lower surface structure C, which is also closely connected by three layers of tissue; the third is the core structure B , formed by the hollow connection of the inner layers of the upper and lower surface layers by the core binding warp at a faster warp let-off speed, and the core binding warp is a V-shaped connection.

Fig. 2 is a longitudinal cross-sectional view of a fabric structure composed of multiple yarns in Embodiment 1 of the method of the present invention. The whole fabric is structurally composed of three parts woven by 18 yarns: upper surface structure A, core structure B and lower surface structure C. Corresponding to that shown in Figure 1, the composition of the upper surface structure A is composed of three layers of weaves connected by the upper surface layer and the warp yarns are tightly attached to each other, and the composition of the lower surface structure C is also composed of three layers of weave It is formed by connecting the warp yarns of the lower surface layer closely, and the core structure B is formed by hollow connection of the inner layers of the upper and lower surface layers by the core binding warp at a faster let-off speed.

Fig. 3 is the locus diagram of the warp thread of the method embodiment 1 of the present invention, has shown each warp thread around or the mode of movement of weft yarn, and this kind of around mode has just constituted fabric structure. Because in Figure 2, the longitudinal cross-sectional view of the fabric is composed of multiple yarns, because there is overlap between the yarns, it is difficult to describe clearly, so it is accurately and clearly shown in Figure 3. In the figure, each warp yarn is arranged according to the drawing-in order on the loom. Fig. 3 has not only represented the detailed structural mode that each yarn of the present invention's method embodiment one forms the whole fabric structure, and, this mode is also exactly for the present invention's method embodiment one as the main fabric-forming mechanism of the loom Movement of the heald frame. Shown in Fig. 3: upper surface warp yarns 1, 2, 3, 10, 11, 12 form three tissue of upper surface, and upper surface connecting warp yarns 7, 16 then form the penetrating connection to the three tissue of upper surface, The three tissues of the upper surface are tightly connected into one; correspondingly, the warp yarns 4, 5, 6, 13, 14, and 15 of the lower surface form the three tissues of the lower surface, and the connecting warp yarns 8 and 17 of the lower surface form a pair of lower surface layers. The penetrating connection of the three pieces of tissue on the surface tightly connects the three pieces of tissue on the lower surface into one; the hollow core spacer connecting warp yarns 9 and 18 are located between the upper and lower surface layers, forming a hollow form for the upper surface layer and the lower surface layer The connection of the fabric structure forms a hollow part between the upper and lower skins. The surface layer connecting warp yarns 7, 8, 16, 17 are let off at a slower speed than the hollow space connecting warp yarns 9, 18. The synthesis of Fig. 3 has just formed the fabric of the woven hollow core structure that the surface layer shown in Fig. 1, 2 is a multi-layer structure.

Fig. 4 is a weaving process diagram of the fabric of the method embodiment 1 of the present invention on the dobby loom. The left figure in Fig. 4 shows the drawing-in diagram of each warp yarn in embodiment one, adopts 18 pages of heald frames, and 18 warp yarns are drawn in order from left to right 1, 2, 3, etc. The right figure in Fig. 4 shows the pattern pattern of the control dobby mechanism in the first embodiment. The drafting diagram and pattern diagram are the most important technical drawings for weaving, and are the key to realizing the specific structure of the fabric. The corresponding technical settings of the loom can be made according to the technical diagram, and the corresponding fabric can be woven.

The above four figures completely represent the fabric structure and weaving technology of Embodiment 1 of the present invention.

Embodiment two:

Fig. 5 is a longitudinal sectional view of the woven hollow structure of the second embodiment of the method of the present invention, showing that the surface layer is a three-layer structure, and the core is connected by a W-shaped woven hollow structure. Wherein, in the left figure of Fig. 5, the upper surface layer warp yarns 1, 2, 3, 10, 11, 12 are interwoven with the weft yarns to form three layers of parallel fabrics on the upper surface layer, and the lower surface layer warp yarns 4, 5, 6, 13, 14 , 15 interweaves with weft yarns to form three layers of fabric parallel to each other on the lower surface layer; the upper surface layer binding warp 7, 11 runs through the uppermost layer and the lowermost layer of the upper surface layer alternately, and the lower surface layer binding warp 8, 17- It runs through the uppermost layer and the lowermost layer of the lower surface layer alternately, as shown in the middle figure of Figure 5, forming a tight three-layer structure of the upper and lower surface layers; the hollow cores connect the warp yarns 9 and 18 in a W-shaped pattern They appear in the innermost layer of the upper and lower surface layers in turn, as shown in the right figure in Figure 5, connecting the inner layers of the upper and lower surface layers, thus forming an overall spaced hollow core structure.

The main difference between the second embodiment of Fig. 5 and the first embodiment of Figs. Those that belong to the same category technically have similar descriptions, so they are omitted.

Embodiment three:

Fig. 6 is a longitudinal cross-sectional view of the woven hollow reinforcement body according to the third embodiment of the method of the present invention. The left figure in Fig. 6 shows a woven hollow core structure in which the surface layer is a two-layer structure and the core joint is V-shaped. Upper surface warp yarns 1, 2, 10, 11 interweave with weft yarns to form two layers of parallel fabrics on the upper surface layer, and lower surface layer warp yarns 4, 5, 13, 14 interweave with weft yarns to form two layers of parallel fabrics on the lower surface layer, The junction of the upper surface layer runs through the uppermost layer and the lowermost layer of the upper surface layer through 7 and 11 alternately, and the junction of the lower surface layer passes through the uppermost layer and the lowermost layer of the lower surface layer through 8 and 17 alternately. As shown in the middle figure of Fig. 6, a tight joint two-layer structure of the upper and lower surface layers is formed; the hollow-core interval connecting warp yarns 9 and 18 appear in the innermost layer of the upper and lower surface layers in turn in a V-shaped pattern, as shown on the right in Fig. 6 As shown in the figure, the inner layers of the upper and lower surface layers are connected, so that a fabric with an integral spaced hollow core structure is formed.

The main difference between embodiment three of Fig. 6 and embodiment one of Fig. 1-Fig. 4 is that the number of layers of the upper and lower surface layers is different. The number of layers is 2, and the descriptions in terms of implementation and technology are similar, so they are omitted.

Claims (8)

1. a high-strength woven hollow strengthens the weaving method of body, it is characterized in that: core is woven as access node when hollow connects up and down two superficial layers, and two superficial layers itself are woven into access node through multilayer tissue that paste layer connects up and down.

2. formation method according to claim 1 is characterized in that: the tissue that constitutes the upper and lower surfaces layer can adopt any monolayer organization.

3. high-strength woven hollow according to claim 1 strengthens the weaving method of body, it is characterized in that: upper surface layer or undersurface layer are carried out access node that paste layer connects through weaving motion with the mode that runs through upper surface layer or undersurface layer.

4. high-strength woven hollow according to claim 1 strengthens the weaving method of body, it is characterized in that: the core access node connects through the internal layer of two superficial layers is up and down carried out hollow.

5. high-strength woven hollow according to claim 1 strengthens the weaving method of body, it is characterized in that: the core access node connects through with the V-type motion mode two superficial layers up and down being carried out hollow.

6. high-strength woven hollow according to claim 1 strengthens the weaving method of body, it is characterized in that: the core access node connects through with W type motion mode two superficial layers up and down being carried out hollow.

7. high-strength woven hollow according to claim 1 strengthens the weaving method of body, it is characterized in that: the access node of upper surface layer or undersurface layer is through carrying out the paste layer connection with the V-type motion mode to upper surface layer or undersurface layer.

8. high-strength woven hollow according to claim 1 strengthens the weaving method of body, it is characterized in that: the access node of upper surface layer or undersurface layer is through carrying out the paste layer connection with W type motion mode to upper surface layer or undersurface layer.

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