A high-temperature resistant FRP pipe, manufacturing method and truss

Abstract

The present invention discloses a high-temperature resistant FRP pipe, which comprises a tubular resin matrix, a modified flame-retardant short fiber felt, and longitudinal fiber bundles. The modified flame-retardant short fiber felt is embedded in the tubular resin matrix. The modified flame-retardant short fiber felt comprises a low-melting-point fiber layer and a foaming and expanding type fireproof core material. When the low-melting-point fiber layer is heated to the melting temperature, it melts into a network channel. When the foaming and expanding type fireproof core material is heated to the foaming temperature, it foams and expands. The foaming and expanding type fireproof core material is wrapped inside the low-melting-point fiber layer. Each longitudinal fiber bundle is embedded in the tubular resin matrix, and each longitudinal fiber bundle is distributed circumferentially around the tubular resin matrix and is located inside the foaming and expanding type fireproof core material. The manufacturing method of the high-temperature resistant FRP pipe and a truss including the high-temperature resistant FRP pipe are also disclosed. The high-temperature resistant FRP pipe and the truss have the advantages of being convenient for transportation, being able to take into account both mechanical properties and fireproof properties, etc. The manufacturing method of the high-temperature resistant FRP pipe can manufacture the high-temperature resistant FRP pipe and is convenient for production.

Description

Technical Field

[0001] The present invention relates to the technical field of composite pipes, and particularly relates to a high-temperature resistant FRP pipe, a manufacturing method and a truss. Background Art

[0002] Fiber Reinforced Polymer (FRP) profiles have been widely used in civil engineering such as truss structures and bridge decks due to their advantages of light weight, high strength, rust-free and excellent fatigue resistance. Each member of the truss structure only bears axial tension and compression. Using fiber reinforced composites in truss structures is expected to fully utilize the excellent mechanical properties of FRP profiles along the fiber direction. Compared with traditional steel structures, fiber reinforced composite structures have the following advantages: (1) Lightweight structure, the density of FRP is only 1 / 4 of that of steel, which can significantly reduce the self-weight of the truss structure, improve the spanning ability of the truss structure, and facilitate transportation and manual assembly; (2) Rust-free and better fatigue resistance, which can adapt to harsh use environments such as high chloride salt, high acid-base and humidity, as well as the stress state of high stress amplitude, and effectively extend the service life of the truss structure.

[0003] However, during the construction and use of FRP structures, their safety performance is vulnerable to fire threats. The glass transition temperature of the commonly used resin matrix in FRP on the current market is too low, and most of them are only 50 - 120 °C. When the temperature exceeds the glass transition temperature of the resin matrix, the mechanical properties of the resin matrix will decrease significantly, and the bonding performance between the fiber and the resin matrix will decay significantly, resulting in the softening and deformation of the FRP material and the decline of the bearing capacity of the FRP structure. When the temperature further rises, the resin matrix in the FRP will decompose, releasing heat, smoke and toxic volatile substances, and causing the FRP material to completely lose its bearing capacity. Therefore, the research and development of high-temperature resistant or even self-fireproof FRP profiles and corresponding structures have important engineering application values.

[0004] At present, the fire protection measures for FRP structures are as follows: (1) Using a high-temperature resistant resin matrix with a higher glass transition temperature for FRP pipes. This method can improve the fire resistance of FRP pipes to a certain extent, but its effect is difficult to be directly proportional to the economic cost; (2) Coating fire protection coatings (intumescent fire protection coatings, thick fire protection coatings, cement mortar, ceramic refractory fiber blankets, etc.) on the outer surface of FRP pipes. For example, the FRP pipe and manufacturing process disclosed in the Chinese patent application document with the application number CN201410712878.8 coats multiple layers of coatings (erosion-resistant intermediate layer, strengthening outer layer) on the FRP pipe. Although such protection measures can effectively delay the temperature rise rate of FRP pipes, thereby slowing down the attenuation rate of the bearing capacity of FRP pipes and FRP structures under fire, during the operation stage of FRP structures, the fire protection coating is prone to diseases such as peeling and abrasion, which increases the cost of later maintenance; (3) Setting multiple protective layers outside the FRP pipe by means of molding or winding through a mold. For example, a high-temperature resistant and erosion-resistant carbon fiber composite material pipe and its preparation method disclosed in the Chinese patent application document with the application number CN201810060561.9 sets an erosion-resistant layer, a high-temperature strength layer, and a heat insulation layer in sequence on the ablation-resistant layer. However, on the one hand, the outer protective layer only plays an outer protective role for the FRP pipe and has no helpful effect on its mechanical properties. On the other hand, the fire protection performance is poor and cannot take into account both the mechanical properties and fire protection performance of the FRP pipe. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a high-temperature resistant FRP pipe and truss that are convenient for transportation and can take into account both mechanical properties and fire protection performance; it also provides a manufacturing method of a high-temperature resistant FRP pipe that can manufacture high-temperature resistant FRP pipes and is convenient for production.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A high-temperature resistant FRP pipe, comprising a tubular resin matrix, a modified flame-retardant short fiber felt cloth, and a plurality of longitudinal fiber bundles. The tubular resin matrix is a pipe body formed by heating and curing a resin adhesive solution added with a flame retardant. The modified flame-retardant short fiber felt cloth is pre-buried in the tubular resin matrix in a tubular shape and is coaxial with the tubular resin matrix. The modified flame-retardant short fiber felt cloth includes a low-melting-point fiber layer and a foaming and expanding type fireproof core material. When the low-melting-point fiber layer is heated to the melting point temperature, it melts to form a network channel. When the foaming and expanding type fireproof core material is heated to the foaming temperature, it foams and expands to retard fire and insulate heat. The foaming and expanding type fireproof core material is wrapped inside the low-melting-point fiber layer. Each longitudinal fiber bundle is pre-buried in the tubular resin matrix and extends along the axial direction of the tubular resin matrix, and each longitudinal fiber bundle is distributed circumferentially around the tubular resin matrix and is located inside the modified flame-retardant short fiber felt cloth. The foaming temperature of the foaming and expanding type fireproof core material is greater than or equal to the melting point temperature of the low-melting-point fiber layer.

[0008] As a further improvement of the above technical solution:

[0009] The melting point temperature of the low-melting-point fiber layer is 140°C to 160°C.

[0010] The low-melting-point fiber layer is formed by mixing and manufacturing one or several of polypropylene fiber, polyvinyl alcohol fiber, polyacrylonitrile fiber, polyamide fiber, aramid fiber, and polyester fiber.

[0011] The foaming and expanding type fireproof core material is formed by adding a foaming agent to flame-retardant fibers, and the flame-retardant fibers are polyester, viscose fiber, polyamide, or vinylon added with a flame retardant.

[0012] Resin stiffening ribs are integrally formed in the tubular resin matrix, and a plurality of internal fiber bundles are pre-buried in the resin stiffening ribs, and each internal fiber bundle extends along the axial direction of the tubular resin matrix.

[0013] A manufacturing method of the above high-temperature resistant FRP pipe includes the following steps:

[0014] S1. Tighten the longitudinal fiber bundles and the modified flame-retardant short fiber felt cloth: After infiltrating the longitudinal fiber bundles with the resin adhesive solution, pass them through the tubular forming space, so that each longitudinal fiber bundle is tightened along the axial direction of the tubular forming space and is distributed circumferentially around the tubular forming space; after infiltrating the modified flame-retardant short fiber felt cloth with the resin adhesive solution, pass it through the tubular forming space, so that the modified flame-retardant short fiber felt cloth is sleeved outside each longitudinal fiber bundle in a tubular shape and is tightened along the axial direction of the tubular forming space;

[0015] S2. Heat and cure: Heat the tubular forming space to cure the inside of the tubular forming space to form a high-temperature resistant FRP pipe.

[0016] A manufacturing method of the above high-temperature resistant FRP pipe includes the following steps:

[0017] Y1. Tighten the longitudinal fiber bundles and the modified flame-retardant short fiber felt: Tighten each longitudinal fiber bundle along the axial direction of the tubular forming space within the tubular forming space, so that each longitudinal fiber bundle is distributed circumferentially around the tubular forming space; Tighten the modified flame-retardant short fiber felt along the axial direction of the tubular forming space within the tubular forming space, so that the modified flame-retardant short fiber felt is sleeved outside each longitudinal fiber bundle in a tubular shape;

[0018] Y2. Inject resin glue: Inject resin glue into the tubular forming space;

[0019] Y3. Heat and cure: Heat the tubular forming space to cure the interior of the tubular forming space to form a high-temperature resistant FRP pipe.

[0020] A truss is composed of connecting heads and the above-mentioned high-temperature resistant FRP pipes spliced together, and the intersections of the high-temperature resistant FRP pipes are connected through connecting heads.

[0021] As a further improvement of the above technical solution:

[0022] The high-temperature resistant FRP pipe is a round pipe, the connecting head is a ball head, a sleeve is provided on the connecting head, an external thread is provided at the end of the tubular resin matrix, and the sleeve is sleeved with the end of the tubular resin matrix and bonded by ultra-high performance concrete doped with flame-retardant fibers;

[0023] The high-temperature resistant FRP pipe is a square pipe, and the end of the tubular resin matrix is connected to the connecting head by bolts.

[0024] Compared with the prior art, the advantages of the present invention are:

[0025] For the high-temperature resistant FRP pipe of the present invention, when there is no fire during the normal use stage, the modified flame-retardant short fiber felt and the longitudinal fiber bundle buried inside the tubular resin matrix deform coordinately with the tubular resin matrix and bear force together, which can improve the shear strength of the high-temperature resistant FRP pipe. That is to say, the modified flame-retardant short fiber felt and the longitudinal fiber bundle are buried in the tubular resin matrix, which can improve the comprehensive mechanical properties of the tubular resin matrix such as the strength of bearing axial tension and pressure and the shear strength. At the same time, the modified flame-retardant short fiber felt is buried in the tubular resin matrix, is not easy to fall off and wear, and is convenient for transportation. After a fire occurs, when the low-melting-point fiber layer is heated to the melting temperature, the low-melting-point fiber layer melts, thereby forming a network channel in the original space of the low-melting-point fiber layer or on the inner side of the original space. When the foaming and expanding type fireproof core material is heated to the foaming temperature, the foaming and expanding type fireproof core material foams and expands, fills the space formed after the melting of the low-melting-point fiber layer, and acts together with the flame retardant inside the tubular resin matrix to provide a flame retardant and heat insulation barrier for the tubular resin matrix and the longitudinal fiber bundle inside the low-melting-point fiber layer, thereby realizing the self-fireproof function. Taking the melting of the low-melting-point fiber layer as a node, before this node, the original cloth structure of the modified flame-retardant short fiber felt and the internal longitudinal fiber bundle act together, which can improve the comprehensive mechanical properties of the tubular resin matrix such as the strength of bearing axial tension and pressure and the shear strength, and meet the stronger use requirements of buildings; after this node, although the melted low-melting-point fiber layer in a network shape weakens the improvement of the comprehensive mechanical properties of the tubular resin matrix, but after the foaming and expanding type fireproof core material foams and expands to fill the space formed after the melting of the low-melting-point fiber layer, the flame retardant and heat insulation performance increases, which can well protect the longitudinal fiber bundle and the tubular resin matrix inside the foaming and expanding type fireproof core material, so that the longitudinal fiber bundle and the tubular resin matrix inside the foaming and expanding type fireproof core material can maintain good mechanical properties after being affected by the fire, so that the high-temperature resistant FRP pipe can still be used normally after being affected by the fire. Therefore, the high-temperature resistant FRP pipe of the present invention has the following advantages: First, under the protection of the outer tubular resin matrix, the modified flame-retardant short fiber felt is not easy to fall off and wear, and is convenient for transportation. The combination of the modified flame-retardant short fiber felt and the inner longitudinal fiber bundle improves the mechanical properties of the tubular resin matrix; Second, the modified flame-retardant short fiber felt has the properties of outer layer melting and inner layer expansion. After being melted and expanded by the fire, it can improve the flame retardant and heat insulation performance, thereby protecting the inner longitudinal fiber bundle and the tubular resin matrix, and preventing the mechanical properties of the inner longitudinal fiber bundle and the tubular resin matrix from being damaged, achieving the effect of taking into account both mechanical properties and fireproof performance.

[0026] The manufacturing method of the high-temperature resistant FRP pipe of the present invention, on the one hand, can manufacture a high-temperature resistant FRP pipe with the advantages of Embodiment 1 and Embodiment 2. On the other hand, through the method of tensioning and heat curing, it is convenient to continuously produce section by section along the production line. For example, the tubular forming space is formed by a mold, and the longitudinal fiber bundle and the modified flame-retardant short fiber felt pass through the tubular forming space in a tensioned state. As long as the position is adjusted by pulling, it can meet the heat curing of another section of the high-temperature resistant FRP pipe, and there is no need to repeatedly tension the longitudinal fiber bundle and the modified flame-retardant short fiber felt.

[0027] The truss of the present invention includes a high-temperature resistant FRP pipe and has all the advantages of the high-temperature resistant FRP pipe. Brief Description of the Drawings

[0028] Figure 1 is a schematic perspective view of an embodiment of the high-temperature resistant FRP pipe of the present invention.

[0029] Figure 2 is Figure 1 the front view structural schematic diagram of.

[0030] Figure 3 is Figure 2 the sectional structural schematic diagram of A-A in.

[0031] Figure 4 is a schematic perspective view of another embodiment of the high-temperature resistant FRP pipe of the present invention.

[0032] Figure 5 is a schematic perspective view of an embodiment of the truss of the present invention.

[0033] Figure 6 is Figure 5 the connection structural schematic diagram of the tubular resin matrix and the connector in.

[0034] Figure 7 is a schematic perspective view of another embodiment of the truss of the present invention.

[0035] Each label in the figure represents:

[0036] 1, tubular resin matrix; 2, modified flame-retardant short fiber felt; 21, low melting point fiber layer; 22, foaming and expanding type fireproof core material; 3, longitudinal fiber bundle; 4, resin stiffening rib; 5, internal fiber bundle; 6, connector; 61, screw sleeve; 7, sleeve; 71, screw rod; 8, external thread; 9, ultra-high performance concrete. Detailed Description of the Invention

[0037] The present invention will be further described in detail below in conjunction with the specification drawings and specific embodiments.

[0038] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0040] In the present invention, unless otherwise clearly specified and limited, the terms "assemble", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] Embodiment 1:

[0042] Figures 1 to 3 An embodiment of the high temperature resistant FRP pipe of the present invention is shown. The high temperature resistant FRP pipe of this embodiment includes a tubular resin matrix 1, a modified flame retardant short fiber felt cloth 2 and a plurality of longitudinal fiber bundles 3. The tubular resin matrix 1 is a tube body formed by heating and curing a resin glue liquid with a flame retardant added thereto. The modified flame retardant short fiber felt cloth 2 is pre-buried in the tubular resin matrix 1 in a tubular shape and is coaxial with the tubular resin matrix 1. The modified flame retardant short fiber felt cloth 2 includes a low melting point fiber layer 21 and a foamed expansion type fireproof core material 22. The low melting point fiber layer 21 is heated to a melting point. The foamed fireproof core material 22 melts at a certain temperature to form a network channel. When the foamed fireproof core material 22 is heated to the foaming temperature, it foams and expands to be flame retardant and heat-insulating. The low-melting-point fiber layer 21 is wrapped with the foamed fireproof core material 22. Each longitudinal fiber bundle 3 is pre-buried in the tubular resin matrix 1 and extends along the axial direction of the tubular resin matrix 1. Each longitudinal fiber bundle 3 is distributed circumferentially around the tubular resin matrix 1 and is located on the inner side of the modified flame-retardant short fiber felt cloth 2. The foaming temperature of the foamed fireproof core material 22 is greater than or equal to the melting point temperature of the low-melting-point fiber layer 21.

[0043] In the normal use stage when no fire occurs, for this high-temperature resistant FRP pipe, the modified flame-retardant short fiber felt 2 and the longitudinal fiber bundle 3 buried inside the tubular resin matrix 1 deform coordinately with the tubular resin matrix 1 and bear force together, which can improve the shear strength of the high-temperature resistant FRP pipe. That is to say, when the modified flame-retardant short fiber felt 2 and the longitudinal fiber bundle 3 are buried in the tubular resin matrix 1, the comprehensive mechanical properties such as the strength of the tubular resin matrix 1 to withstand axial tension and pressure and the shear strength can be improved. At the same time, the modified flame-retardant short fiber felt 2 is buried in the tubular resin matrix 1, not easy to fall off and wear, and is convenient for transportation. After a fire occurs, when the low-melting-point fiber layer 21 is heated to the melting temperature, the low-melting-point fiber layer 21 melts, thus forming a network channel in the original space of the low-melting-point fiber layer 21 or on the inner side of the original space. When the foaming and expanding type fireproof core material 22 is heated to the foaming temperature, the foaming and expanding type fireproof core material 22 foams and expands and acts together with the flame retardant inside the tubular resin matrix 1 to provide a flame retardant and heat insulation barrier for the tubular resin matrix 1 and the longitudinal fiber bundle 3 inside the low-melting-point fiber layer 21, thereby realizing the self-fireproof function. This high-temperature resistant FRP pipe takes the melting of the low-melting-point fiber layer 21 as a node. Before this node, the original cloth structure of the modified flame-retardant short fiber felt 2 and the internal longitudinal fiber bundle 3 act together, which can improve the comprehensive mechanical properties such as the strength of the tubular resin matrix 1 to withstand axial tension and pressure and the shear strength, meeting the stronger use requirements of buildings; after this node, although the melted low-melting-point fiber layer 21 in a network shape (the network channel can be considered as the mesh holes of the network-shaped low-melting-point fiber layer 21) weakens the improvement of the comprehensive mechanical properties of the tubular resin matrix 1, but after the foaming and expanding type fireproof core material 22 foams and expands to fill the space formed after the melting of the low-melting-point fiber layer 21, the flame retardant and heat insulation performance increases, which can well protect the longitudinal fiber bundle 3 and the tubular resin matrix 1 inside the modified flame-retardant short fiber felt 2, so that the longitudinal fiber bundle 3 and the tubular resin matrix 1 inside the modified flame-retardant short fiber felt 2 can maintain good mechanical properties after being affected by the fire, so that the high-temperature resistant FRP pipe can still be used normally after being affected by the fire. Therefore, this high-temperature resistant FRP pipe has the following advantages: First, under the protection of the outer tubular resin matrix 1, the modified flame-retardant short fiber felt 2 is not easy to fall off and wear, and is convenient for transportation. The combination of the modified flame-retardant short fiber felt 2 and the inner longitudinal fiber bundle 3 improves the mechanical properties of the tubular resin matrix 1; Second, the modified flame-retardant short fiber felt 2 has the properties of outer layer melting and inner layer expansion. After melting and expanding under fire, it can improve the flame retardant and heat insulation performance, thereby protecting the inner longitudinal fiber bundle 3 and the tubular resin matrix 1 and preventing the mechanical properties of the inner longitudinal fiber bundle 3 and the tubular resin matrix 1 from being damaged, achieving the effect of taking into account both mechanical properties and fire protection performance.

[0044] Preferably, the foaming temperature of the foamed expandable fireproof core material 22 is equal to or close to the melting point temperature of the low-melting-point fiber layer 21. In this way, the space after the low-melting-point fiber layer 21 is melted can be filled in time by the foamed expansion of the foamed expandable fireproof core material 22, which can timely replace and support the tubular resin matrix 1 on the outside of the modified flame-retardant short fiber felt cloth 2, thereby improving the fire resistance of the tubular resin matrix 1 on the outside of the modified flame-retardant short fiber felt cloth 2, which in turn helps to increase the overall fire resistance.

[0045] It should be noted that before the foaming temperature is reached, the foamed expandable fire-proof core material 22 is in a stable environment wrapped by the outer protective layer of low-melting-point fiber layer 21, which avoids chemical reactions between the foamed expandable fire-proof core material 22 and the environment during production, processing, manufacturing and operation, and is conducive to ensuring the effectiveness of the foamed expandable fire-proof core material 22.

[0046] Furthermore, in this embodiment, the melting point of the low-melting-point fiber layer 21 is 140° C. to 160° C.

[0047] Furthermore, in this embodiment, the low-melting-point fiber layer 21 is formed by one or a mixture of polypropylene fiber, polyvinyl alcohol fiber, polyacrylonitrile fiber, polyamide fiber, aramid fiber, and polyester fiber.

[0048] Furthermore, in the present embodiment, the foamed expandable fireproof core material 22 is formed by adding a foaming agent to a flame retardant fiber, and the flame retardant fiber is polyester, viscose fiber, nylon or vinylon added with a flame retardant.

[0049] Furthermore, if Figure 1 and Figure 2 As shown, in this embodiment, a resin stiffening rib 4 is integrally formed in the tubular resin matrix 1 , and a plurality of internal fiber bundles 5 are pre-embedded in the resin stiffening rib 4 , and each internal fiber bundle 5 extends along the axial direction of the tubular resin matrix 1 .

[0050] The resin stiffening ribs 4 form a support inside the tubular resin matrix 1, effectively increasing the local stiffness of the tubular resin matrix 1, avoiding local buckling, and also delaying the attenuation rate of the stress performance of the compression rods and tension rods of the tubular resin matrix 1 under fire, thereby improving the fire resistance and mechanical properties of the tubular resin matrix 1.

[0051] Furthermore, in this embodiment, the resin stiffening rib 4 is in a cross shape, and its center coincides with the central axis of the tubular resin matrix 1. Of course, in other embodiments, the resin stiffening rib 4 can also be in other shapes such as a straight line shape or a cross shape.

[0052] Further, in this embodiment, the cross-section of the tubular resin matrix 1 is circular, that is, the high-temperature resistant FRP pipe is a circular pipe. Similarly, the cross-section of the modified flame-retardant short fiber felt cloth 2 is also circular, that is, the cross-sections of both the low-melting-point fiber layer 21 and the foaming and expanding fireproof core material 22 are circular.

[0053] It should be further noted that the fibers in the modified flame-retardant short fiber felt cloth 2 wrap the foaming and expanding fireproof core material 22 inside, so that it is convenient to add the modified flame-retardant short fiber felt cloth 2 and the foaming and expanding fireproof core material 22 inside it into the profile fiber (tubular resin matrix 1).

[0054] Embodiment Two:

[0055] Figure 4 Another embodiment of the high-temperature resistant FRP pipe of the present invention is provided. The structure of this embodiment is basically the same as that of Embodiment One, with the only difference being that: the cross-section of the tubular resin matrix 1 is square, that is, the high-temperature resistant FRP pipe is a square pipe. Similarly, the cross-section of the modified flame-retardant short fiber felt cloth 2 is also square, that is, the cross-sections of both the low-melting-point fiber layer 21 and the foaming and expanding fireproof core material 22 are square.

[0056] Embodiment Three:

[0057] An embodiment of the manufacturing method of the high-temperature resistant FRP pipes in Embodiment One and Embodiment Two. The manufacturing method of the high-temperature resistant FRP pipe in this embodiment is as follows:

[0058] S1. Tighten the longitudinal fiber bundles 3 and the modified flame-retardant short fiber felt cloth 2: After infiltrating each longitudinal fiber bundle 3 with resin glue, pass it through the tubular forming space, so that each longitudinal fiber bundle 3 is tightened along the axial direction of the tubular forming space and distributed around the circumferential direction of the tubular forming space; after infiltrating the modified flame-retardant short fiber felt cloth 2 with resin glue, pass it through the tubular forming space, so that the modified flame-retardant short fiber felt cloth 2 is sleeved outside each longitudinal fiber bundle 3 in a tubular shape and tightened along the axial direction of the tubular forming space;

[0059] S2. Heat and cure: Heat the tubular forming space to cure the inside of the tubular forming space to form a high-temperature resistant FRP pipe.

[0060] The manufacturing method of this high-temperature resistant FRP pipe, on the one hand, can manufacture high-temperature resistant FRP pipes with the advantages of Embodiment One and Embodiment Two. On the other hand, through the method of tightening and heat curing, it is convenient to continuously produce section by section along the production line. For example, if the tubular forming space is formed by a mold, the longitudinal fiber bundles 3 and the modified flame-retardant short fiber felt cloth 2 pass through the tubular forming space in a tightened state. As long as the position is adjusted by pulling, it can meet the heat curing of another section of the high-temperature resistant FRP pipe, and there is no need to repeatedly loosen the longitudinal fiber bundles 3 and the modified flame-retardant short fiber felt cloth 2.

[0061] Further, in this embodiment, the tubular forming space is formed by a mold. Two tubular forming spaces can be successively arranged. The tensioned longitudinal fiber bundles 3 and the modified flame-retardant short fiber felt 2 can first pass through the previous tubular forming space to discharge the excess resin adhesive and air bubbles, and then pass through the latter tubular forming space to be heated and cured to form a high-temperature resistant FRP pipe.

[0062] Embodiment 4:

[0063] Another embodiment of the manufacturing method of the high-temperature resistant FRP pipe in Embodiment 1 and Embodiment 2. The manufacturing method of the high-temperature resistant FRP pipe in this embodiment includes the following steps:

[0064] Y1. Tension the longitudinal fiber bundles 3 and the modified flame-retardant short fiber felt 2: Tension each longitudinal fiber bundle 3 along the axial direction of the tubular forming space in the tubular forming space, so that each longitudinal fiber bundle 3 is distributed around the circumference of the tubular forming space; Tension the modified flame-retardant short fiber felt 2 along the axial direction of the tubular forming space in the tubular forming space, so that the modified flame-retardant short fiber felt 2 is sleeved on the outside of each longitudinal fiber bundle 3 in a tubular shape;

[0065] Y2. Inject the resin adhesive: Inject the resin adhesive into the tubular forming space;

[0066] Y3. Heat and cure: Heat the tubular forming space to cure the inside of the tubular forming space to form a high-temperature resistant FRP pipe.

[0067] The manufacturing method of this high-temperature resistant FRP pipe, on the one hand, can manufacture a high-temperature resistant FRP pipe with the advantages of Embodiment 1 and Embodiment 2. On the other hand, through the method of tensioning and heat curing, it is convenient for continuous production section by section along the production line. For example, if the tubular forming space is formed by a mold, the longitudinal fiber bundles 3 and the modified flame-retardant short fiber felt 2 pass through the tubular forming space in a tensioned state. As long as the position is adjusted by pulling, it can meet the heat curing of another section of the high-temperature resistant FRP pipe, and it is not necessary to repeatedly loosen the longitudinal fiber bundles 3 and the modified flame-retardant short fiber felt 2. Compared with Embodiment 3, the longitudinal fiber bundles 3 and the modified flame-retardant short fiber felt 2 in this embodiment do not need to be pre-infiltrated with the resin adhesive in advance, but the resin adhesive is injected into the latter tubular forming space, which can reduce the loss of the resin adhesive dropping during the movement of the longitudinal fiber bundles 3 and the modified flame-retardant short fiber felt 2.

[0068] Embodiment 5:

[0069] Figure 5 and Figure 6 shows an embodiment of the truss of the present invention. The truss in this embodiment is composed of a connector 6 and the high-temperature resistant FRP pipes in Embodiment 1, and the intersections of the high-temperature resistant FRP pipes are connected by the connector 6. This truss includes high-temperature resistant FRP pipes and has all the advantages of high-temperature resistant FRP pipes. Compared with traditional steel truss members, it has the advantages of light weight, corrosion resistance and fatigue resistance.

[0070] Furthermore, in this embodiment, the high-temperature resistant FRP pipe is a circular pipe, the connector 6 is a ball head, a sleeve 7 is provided on the connector 6, an external thread 8 is provided at the end of the tubular resin matrix 1, and the sleeve 7 is sleeved on the end of the tubular resin matrix 1 and bonded by ultra-high performance concrete 9 doped with flame retardant fibers. On the one hand, it is convenient for disassembly and assembly, has good connection efficiency and excellent corrosion resistance; on the other hand, the sleeve 7 is sleeved on the end of the tubular resin matrix 1 and bonded by ultra-high performance concrete 9 doped with flame retardant fibers, which can delay the temperature rise rate at the intersection (node area) under fire and avoid the failure of the intersection under fire, thereby effectively improving the fire resistance of the intersection.

[0071] Furthermore, in this embodiment, the sleeve 7 is made of aluminum alloy. A screw sleeve 61 is fixedly provided on the connector 6, a screw rod 71 is fixedly provided on the sleeve 7, and the screw rod 71 is threadedly connected with the screw sleeve 61. Thermal barrier coatings are provided on the surfaces of the sleeve 7, the screw sleeve 61, the screw rod 71 and the connector 6, which can delay the temperature rise rate under fire and effectively improve the fire resistance.

[0072] Embodiment Six:

[0073] Figure 7 Another embodiment of the truss of the present invention is shown. The truss of this embodiment is composed of the connector 6 and the high-temperature resistant FRP pipe of Embodiment Two, and the intersections of the high-temperature resistant FRP pipes are connected by the connector 6. In this embodiment, the high-temperature resistant FRP pipe is a square pipe, and the end of the tubular resin matrix 1 is bolted to the connector 6. This truss includes high-temperature resistant FRP pipes and has all the advantages of high-temperature resistant FRP pipes. Compared with traditional steel truss members, it has the advantages of light weight, corrosion resistance and fatigue resistance.

[0074] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent embodiment with equivalent changes, without departing from the scope of the technical solution of the present invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A high-temperature resistant FRP pipe, characterized in that: It includes a tubular resin matrix (1), a modified flame-retardant short fiber felt (2), and multiple longitudinal fiber bundles (3). The tubular resin matrix (1) is a tube formed by heating and curing a resin adhesive solution added with a flame retardant. The modified flame-retardant short fiber felt (2) is pre-buried in the tubular resin matrix (1) in a tubular shape and is coaxial with the tubular resin matrix (1). The modified flame-retardant short fiber felt (2) includes a low-melting-point fiber layer (21) and a foaming and expanding type fireproof core material (22). When the low-melting-point fiber layer (21) is heated to the melting point temperature, it melts to form a network channel. When the foaming and expanding type fireproof core material (22) is heated to the foaming temperature, it foams and expands to provide flame retardancy and heat insulation. The foaming and expanding type fireproof core material (22) is wrapped inside the low-melting-point fiber layer (21). Each longitudinal fiber bundle (3) is pre-buried in the tubular resin matrix (1) and extends along the axial direction of the tubular resin matrix (1), and each longitudinal fiber bundle (3) is distributed around the circumference of the tubular resin matrix (1) and is located inside the modified flame-retardant short fiber felt (2). The foaming temperature of the foaming and expanding type fireproof core material (22) is greater than or equal to the melting point temperature of the low-melting-point fiber layer (21).

2. The high-temperature resistant FRP pipe according to claim 1, wherein: The melting point temperature of the low-melting-point fiber layer (21) is 140°C to 160°C.

3. The high-temperature resistant FRP pipe according to claim 1, wherein: The low-melting-point fiber layer (21) is formed by mixing one or more of polypropylene fiber, polyvinyl alcohol fiber, polyacrylonitrile fiber, polyamide fiber, aramid fiber, and polyester fiber.

4. The high-temperature resistant FRP pipe according to claim 1, characterized in that: The foaming and expanding type fireproof core material (22) is formed by adding a foaming agent to flame-retardant fibers, and the flame-retardant fibers are polyester, viscose fiber, polyamide, or vinylon added with a flame retardant.

5. The high-temperature resistant FRP pipe according to any one of claims 1 to 4, characterized in that: Resin stiffening ribs (4) are integrally formed inside the tubular resin matrix (1), and multiple internal fiber bundles (5) are pre-buried in the resin stiffening ribs (4), and each internal fiber bundle (5) extends along the axial direction of the tubular resin matrix (1).

6. The manufacturing method of a high-temperature resistant FRP pipe according to any one of claims 1 to 5, characterized in that, It includes the following steps: S1. Tighten the longitudinal fiber bundles (3) and the modified flame-retardant short fiber felt (2): After infiltrating each longitudinal fiber bundle (3) with a resin adhesive solution, pass it through the tubular forming space, so that each longitudinal fiber bundle (3) is tightened along the axial direction of the tubular forming space and is distributed around the circumference of the tubular forming space; after infiltrating the modified flame-retardant short fiber felt (2) with a resin adhesive solution, pass it through the tubular forming space, so that the modified flame-retardant short fiber felt (2) is sleeved outside each longitudinal fiber bundle (3) in a tubular shape and is tightened along the axial direction of the tubular forming space; S2. Heat and cure: Heat the tubular forming space to cure the inside of the tubular forming space to form a high-temperature resistant FRP tube.

7. The manufacturing method of the high-temperature resistant FRP pipe according to any one of claims 1 to 5, characterized in that, It includes the following steps: Y1. Tighten the longitudinal fiber bundles (3) and the modified flame-retardant short fiber felt (2): Tighten each longitudinal fiber bundle (3) along the axial direction of the tubular forming space inside the tubular forming space, so that each longitudinal fiber bundle (3) is distributed around the circumference of the tubular forming space; tighten the modified flame-retardant short fiber felt (2) along the axial direction of the tubular forming space inside the tubular forming space, so that the modified flame-retardant short fiber felt (2) is sleeved outside each longitudinal fiber bundle (3) in a tubular shape; Y2. Inject resin adhesive solution: Inject the resin adhesive solution into the tubular forming space. Y3. Heating and curing: Heat the tubular forming space to cure the interior of the tubular forming space to form a high-temperature resistant FRP pipe.

8. A truss, characterized in that: It is composed of a connector (6) and the high-temperature resistant FRP pipe described in any one of claims 1 to 5, and the intersection of the high-temperature resistant FRP pipes is connected through the connector (6).

9. The truss according to claim 8, characterized in that: The high-temperature resistant FRP pipe is a round pipe, the connector (6) is a ball head, a sleeve (7) is provided on the connector (6), an external thread (8) is provided at the end of the tubular resin matrix (1), and the sleeve (7) is sleeved with the end of the tubular resin matrix (1) and bonded by ultra-high performance concrete (9) doped with flame retardant fibers.

10. The truss according to claim 8, wherein: The high-temperature resistant FRP pipe is a square pipe, and the end of the tubular resin matrix (1) is connected to the connector (6) by bolts.

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