High-temperature-resistant FRP pipe, manufacturing method and truss

Abstract

The invention discloses a high-temperature-resistant FRP pipe which comprises a tubular resin matrix, modified flame-retardant short fiber felt cloth and longitudinal fiber bundles, the modified flame-retardant short fiber felt cloth is pre-buried in the tubular resin matrix, and the modified flame-retardant short fiber felt cloth comprises a low-melting-point fiber layer and a foaming expansion type fireproof core material; the low-melting-point fiber layer is melted into a net-shaped channel when heated to the melting point temperature, the foaming expansion type fireproof core material is foamed and expanded when heated to the foaming temperature, the foaming expansion type fireproof core material is wrapped in the low-melting-point fiber layer, and all the longitudinal fiber bundles are pre-buried in the tubular resin matrix. The longitudinal fiber bundles are distributed in the circumferential direction of the tubular resin base body and located on the inner side of the foaming expansion type fireproof core material. The invention further discloses a manufacturing method of the high-temperature-resistant FRP pipe and a truss comprising the high-temperature-resistant FRP pipe. The high-temperature-resistant FRP pipe and the truss have the advantages of being convenient to transport, good in mechanical performance and fireproof performance and the like. The manufacturing method of the high-temperature-resistant FRP pipe can be used for manufacturing the high-temperature-resistant FRP pipe and is convenient to produce.

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] Due to advantages such as light weight, high strength, rust-free and excellent fatigue resistance, fiber reinforced composite (FRP) profiles have been widely used in civil engineering such as truss structures and bridge decks. Each member of the truss structure only bears axial tension and compression. Using fiber reinforced composites for 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, mostly 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 softening and deformation of the FRP material and a decrease in the load-bearing performance 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 load-bearing capacity. Therefore, developing high-temperature resistant or even self-fireproof FRP profiles and corresponding structures has important engineering application value.

[0004] At present, the fire prevention measures for FRP structures include: (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 not proportional to the economic cost; (2) applying fire retardant coatings (expanding fire retardant coatings, thick coating fire retardant coatings, cement mortar, ceramic refractory fiber blankets, etc.) on the outside of FRP pipes. For example, the FRP pipe and manufacturing process disclosed in the Chinese patent application document with application number CN201410712878.8, which applies multiple layers of coatings (corrosion-resistant middle layer, reinforced outer layer) on the FRP pipe. Although this type of protection measure can effectively slow down the temperature rise rate of the FRP pipe, thereby reducing the load-bearing capacity of the FRP pipe and FRP structure, (3) A multi-layer protective layer is arranged on the outside of the FRP pipe by molding or winding, such as a high-temperature erosion-resistant carbon fiber composite material pipe and a preparation method thereof disclosed in the Chinese patent application document with application number CN201810060561.9, in which an erosion-resistant layer, a high-temperature strength layer and a thermal insulation layer are arranged 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 effect on its mechanical properties. On the other hand, the fire-proof performance is poor, and both the mechanical properties and the fire-proof performance of the FRP pipe cannot be taken into account. 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 which are easy to transport and can take into account both mechanical properties and fire resistance; a method for manufacturing high temperature resistant FRP pipes which can be manufactured and is easy to produce is also provided.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: 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, wherein the tubular resin matrix 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 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 comprises a low melting point fiber layer and a foaming expansion type fireproof core material, the low melting point fiber layer melts to form a mesh channel when heated to a melting point temperature When the foamed expandable fireproof core material is heated to the foaming temperature, it foams and expands to be flame retardant and heat-insulating. The foamed expandable fireproof core material is wrapped inside the low-melting-point fiber layer. Each of the longitudinal fiber bundles is pre-buried in the tubular resin matrix and extends along the axial direction of the tubular resin matrix. Each of the longitudinal fiber bundles is distributed circumferentially around the tubular resin matrix and is located on the inner side of the modified flame-retardant short fiber felt cloth. The foaming temperature of the foamed expandable fireproof core material is greater than or equal to the melting point temperature of the low-melting-point fiber layer.

[0007] As a further improvement of the above technical solution: The melting point temperature of the low-melting-point fiber layer is 140°C to 160°C.

[0008] The low melting point fiber layer is formed by mixing one or more of polypropylene fiber, polyvinyl alcohol fiber, polyacrylonitrile fiber, polyamide fiber, aramid fiber and polyester fiber.

[0009] The foaming and expanding fireproof core material is formed by adding a foaming agent into a flame retardant fiber, and the flame retardant fiber is polyester, viscose fiber, nylon or vinylon added with a flame retardant.

[0010] A resin stiffening rib is integrally formed in the tubular resin matrix, and a plurality of internal fiber bundles are pre-embedded in the resin stiffening rib, and each of the internal fiber bundles extends along the axial direction of the tubular resin matrix.

[0011] A method for manufacturing the above-mentioned high temperature resistant FRP pipe comprises the following steps: S1. Tightening the longitudinal fiber bundles and the modified flame-retardant short fiber felt cloth: soaking each longitudinal fiber bundle in resin glue and passing it through the tubular molding space, so that each longitudinal fiber bundle is tightened along the axial direction of the tubular molding space and distributed around the circumference of the tubular molding space; soaking the modified flame-retardant short fiber felt cloth in resin glue and passing it through the tubular molding space, so that the modified flame-retardant short fiber felt cloth is tubularly sleeved outside each longitudinal fiber bundle and tightened along the axial direction of the tubular molding space; S2. Heating and curing: heating the tubular forming space to cure the inside of the tubular forming space to form a high temperature resistant FRP tube.

[0012] A method for manufacturing the above-mentioned high temperature resistant FRP pipe comprises the following steps: Y1. Tightening the longitudinal fiber bundles and the modified flame-retardant short fiber felt cloth: Tightening each longitudinal fiber bundle in the tubular molding space along the axial direction of the tubular molding space, so that each longitudinal fiber bundle is distributed around the circumference of the tubular molding space; Tightening the modified flame-retardant short fiber felt cloth in the tubular molding space along the axial direction of the tubular molding space, so that the modified flame-retardant short fiber felt cloth is tubularly sleeved outside each longitudinal fiber bundle; Y2. Injecting resin glue: injecting resin glue into the tubular molding space; Y3. Heating and curing: Heat the tubular forming space to solidify the inside of the tubular forming space to form a high temperature resistant FRP tube.

[0013] A truss is composed of a connector and the above-mentioned high-temperature resistant FRP pipes, wherein the intersections of the high-temperature resistant FRP pipes are connected by the connector.

[0014] As a further improvement of the above technical solution: The high-temperature resistant FRP pipe is a round pipe, the connector is a ball head, a sleeve is provided on the connector, an external thread is provided at the end of the tubular resin matrix, the sleeve is sleeved with the end of the tubular resin matrix and is bonded by ultra-high performance concrete doped with flame retardant fibers; The high-temperature resistant FRP pipe is a square pipe, and the end of the tubular resin matrix is connected to the connector by bolts.

[0015] Compared with the prior art, the advantages of the present invention are as follows: 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 foam-expanding type fireproof core material is heated to the foaming temperature, the foam-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 low-melting-point fiber layer melted into a network weakens the improvement of the comprehensive mechanical properties of the tubular resin matrix, but after the foam-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 foam-expanding type fireproof core material, so that the longitudinal fiber bundle and the tubular resin matrix inside the foam-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 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 melting and expanding under 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.

[0016] The manufacturing method of the high-temperature resistant FRP pipe of the present invention can, on the one hand, manufacture high-temperature resistant FRP pipes 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.

[0017] 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. Description of the Drawings

[0018] Figure 1 is a schematic perspective view of an embodiment of the high-temperature resistant FRP pipe of the present invention.

[0019] Figure 2 is Figure 1 the front view structural schematic diagram of

[0020] Figure 3 is Figure 2 the sectional structural schematic diagram of A-A in

[0021] Figure 4 is a schematic perspective view of another embodiment of the high-temperature resistant FRP pipe of the present invention.

[0022] Figure 5 is a schematic perspective view of an embodiment of the truss of the present invention.

[0023] Figure 6 is Figure 5 the connection structural schematic diagram of the tubular resin matrix and the connector in

[0024] Figure 7 is a schematic perspective view of another embodiment of the truss of the present invention.

[0025] Each label in the figure represents: 1. Tubular resin matrix; 2. Modified flame-retardant short fiber felt; 21. Low melting point fiber layer; 22. Foaming and expanding fireproof core material; 3. Longitudinal fiber bundle; 4. Resin stiffening rib; 5. Internal fiber bundle; 6. Connector; 61. Spiral sleeve; 7. Sleeve; 71. Screw; 8. External thread; 9. Ultra-high performance concrete. Detailed Embodiments

[0026] The present invention will be further described in detail below with reference to the accompanying drawings of the specification and specific embodiments.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] Embodiment 1: 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.

[0031] In the normal use stage when there is no fire, 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 forces 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 2 and the longitudinal fiber bundle 3 are buried in the tubular resin matrix 1, which can improve the comprehensive mechanical properties of the tubular resin matrix 1 such as the strength to bear axial tension and pressure and the shear strength. 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 of the tubular resin matrix 1 such as the strength to bear 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 regarded 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 being melted and expanded by the 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 fireproof performance.

[0032] 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.

[0033] 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.

[0034] Furthermore, in this embodiment, the melting point of the low-melting-point fiber layer 21 is 140° C. to 160° C.

[0035] 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.

[0036] 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.

[0037] 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 .

[0038] 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.

[0039] 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.

[0040] 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 2 is also circular, that is, the cross-sections of the low-melting-point fiber layer 21 and the foaming and expanding fireproof core material 22 are both circular.

[0041] It should be further noted that the fibers in the modified flame-retardant short fiber felt 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 2 and the foaming and expanding fireproof core material 22 inside it into the profile fiber (tubular resin matrix 1).

[0042] Embodiment Two: 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, except 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 2 is also square, that is, the cross-sections of the low-melting-point fiber layer 21 and the foaming and expanding fireproof core material 22 are both square.

[0043] Embodiment Three: 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: S1. Tighten the longitudinal fiber bundles 3 and the modified flame-retardant short fiber felt 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 2 with resin glue, 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 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 pipe.

[0044] 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, 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 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 2.

[0045] 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 excess resin glue and air bubbles, and then pass through the latter tubular forming space for heating and curing to form a high-temperature resistant FRP pipe.

[0046] Embodiment 4: 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: 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 outside each longitudinal fiber bundle 3 in a tubular shape; Y2. Inject resin glue: Inject resin glue into the tubular forming space; 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.

[0047] 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 heating and 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 2 pass through the tubular forming space in a tensioned state. As long as the position is adjusted by pulling, it can meet the heating and 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 resin glue, but resin glue is injected into the latter tubular forming space, which can reduce the loss of resin glue dropping during the movement of the longitudinal fiber bundles 3 and the modified flame-retardant short fiber felt 2.

[0048] Embodiment 5: 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.

[0049] Furthermore, in this embodiment, the high-temperature resistant FRP pipe is a circular pipe, the connecting head 6 is a ball head, a sleeve 7 is provided on the connecting head 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 to disassemble and assemble, 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.

[0050] Furthermore, in this embodiment, the sleeve 7 is made of aluminum alloy. A screw sleeve 61 is fixedly provided on the connecting head 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 connecting head 6, which can delay the temperature rise rate under fire and effectively improve the fire resistance.

[0051] Embodiment Six: Figure 7 Another embodiment of the truss of the present invention is shown. The truss of this embodiment is composed of a connecting head 6 and the high-temperature resistant FRP pipes of Embodiment Two, and the intersections of the high-temperature resistant FRP pipes are connected by the connecting head 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 connecting head 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.

[0052] 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 by using the above-disclosed technical content without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on 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: The invention comprises a tubular resin matrix (1), a modified flame retardant staple fiber felt cloth (2) and a plurality of longitudinal fiber bundles (3), wherein the tubular resin matrix (1) is a tube body formed by heating and curing a resin glue liquid containing a flame retardant, the modified flame retardant staple 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 staple fiber felt cloth (2) comprises a low melting point fiber layer (21) and a foaming expansion type fireproof core material (22), the low melting point fiber layer (21) melts to form a mesh channel when heated to a melting point, the foaming expansion type fireproof core material (22) When the intumescent fireproof core material (22) is heated to a foaming temperature, it foams and expands to provide flame retardancy and heat insulation. The low-melting-point fiber layer (21) wraps the foamed intumescent fireproof core material (22). Each of the longitudinal fiber bundles (3) is pre-buried in the tubular resin matrix (1) and extends along the axial direction of the tubular resin matrix (1). Each of the longitudinal fiber bundles (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 intumescent fireproof core material (22) is greater than or equal to the melting point of the low-melting-point fiber layer (21).

2. The high temperature resistant FRP pipe according to claim 1, characterized in that: The melting point 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, characterized in that: 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.

4. The high temperature resistant FRP pipe according to claim 1, characterized in that: The foaming and expanding fireproof core material (22) is manufactured by adding a foaming agent to flame-retardant fibers, and the flame-retardant fibers are polyester, viscose fibers, nylon 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: 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), each of the internal fiber bundles (5) extending along the axial direction of the tubular resin matrix (1).

6. A method for manufacturing a high temperature resistant FRP pipe according to any one of claims 1 to 5, characterized in that: The steps include: S1, tightening the longitudinal fiber bundles (3) and the modified flame retardant short fiber felt cloth (2): soaking each longitudinal fiber bundle (3) in a resin adhesive and passing it through a tubular molding space, so that each longitudinal fiber bundle (3) is tightened along the axial direction of the tubular molding space and distributed around the circumference of the tubular molding space; soaking the modified flame retardant short fiber felt cloth (2) in a resin adhesive and passing it through the tubular molding space, so that the modified flame retardant short fiber felt cloth (2) is tubularly sleeved outside each longitudinal fiber bundle (3) and tightened along the axial direction of the tubular molding space; S2. Heating and curing: heating the tubular forming space to cure the inside of the tubular forming space to form a high temperature resistant FRP tube.

7. A method for manufacturing a high temperature resistant FRP pipe according to any one of claims 1 to 5, characterized in that: The steps include: Y1. Tightening the longitudinal fiber bundles (3) and the modified flame-retardant short fiber felt cloth (2): Tightening each longitudinal fiber bundle (3) in the tubular molding space along the axial direction of the tubular molding space, so that each longitudinal fiber bundle (3) is distributed around the circumference of the tubular molding space; Tightening the modified flame-retardant short fiber felt cloth (2) in the tubular molding space along the axial direction of the tubular molding space, so that the modified flame-retardant short fiber felt cloth (2) is tubularly sleeved outside each longitudinal fiber bundle (3); Y2. Injecting resin glue: injecting resin glue into the tubular molding space; Y3. Heating and curing: Heat the tubular forming space to solidify the inside of the tubular forming space to form a high temperature resistant FRP tube.

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

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

10. The truss according to claim 8, characterized in that: The high temperature resistant FRP tube is a square tube, and the end of the tubular resin matrix (1) is connected to the connecting head (6) by means of bolts.

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