Bionic fiber reinforced composite material pipe and design method

Abstract

The invention discloses a bionic fiber reinforced composite material pipe and a design method, and belongs to the technical field of positioners, the bionic fiber reinforced composite material pipe comprises an imitated carved owl feather shaft middle section fiber layer, the imitated carved owl feather shaft middle section fiber layer is filled with a medullary foamed structure, the imitated carved owl feather shaft middle section fiber layer comprises a central axial fiber laying layer, and the central axial fiber laying layer is filled with a foamed structure. Transition cross fiber laying layers are arranged on the two sides of the central axial fiber laying layer respectively, and surface circumferential fiber laying layers are arranged on the sides, away from the central axial fiber laying layer, of the two transition cross fiber laying layers respectively. According to the method, bionic research is carried out on the carving-owl feather shaft, the middle section of the carving-owl feather shaft is simulated to carry out composite material gradient layering design and foam filling, the design method based on finite element analysis can obtain the optimal layering thickness of a bionic layering scheme with low cost and high efficiency, scientific fiber arrangement of the fiber reinforced composite material pipe is achieved, and the method is suitable for large-scale popularization and application. The method has obvious advantages in the field of lightweight design of tubular parts.

Description

Technical Field

[0001] The invention discloses a bionic fiber reinforced composite material tube and a design method, belonging to the technical field of positioners. Background Art

[0002] As commonly used load-bearing components in engineering, tubular parts are widely used in mechanical and civil structure design. Tubular parts are often subjected to a variety of complex working conditions such as tension, compression, bending, torsion, vibration, etc. during service. Metal pipes that can meet the above performance requirements are usually heavy, which creates a large load on the system to which the pipe belongs. In the fields of aviation, aerospace, rail transportation, automobiles, etc., there is an urgent need for lightweight design. Fiber-reinforced composite pipes can replace metal pipes due to their light weight and high strength to improve transportation efficiency and save energy.

[0003] Traditional composite pipe layup schemes are usually based on empirical design, with several fixed layup angles and cyclic and symmetrical layup. Traditional layup schemes often produce design redundancy during application, fail to effectively reduce weight, and cause material waste. Summary of the invention

[0004] In view of the defects of the prior art, the present invention proposes a bionic fiber reinforced composite material tube and design method to solve the problem that the current traditional composite material tube layup often produces design redundancy, cannot effectively reduce weight and causes material waste. By conducting bionic research on the eagle owl feather shaft, the middle section of the eagle owl feather shaft is simulated to carry out composite material gradient layup design and foam filling. The design method based on finite element analysis can obtain the optimal layup thickness of the bionic layup scheme with low cost and high efficiency, and realize the scientific fiber arrangement of the fiber reinforced composite material tube, which has obvious advantages in the field of lightweight design of tubular parts.

[0005] The technical solution of the present invention is as follows:

[0006] According to a first aspect of an embodiment of the present invention, a bionic fiber reinforced composite material tube is provided, comprising a fiber layer in the middle section of an eagle owl feather shaft, wherein the fiber layer in the middle section of the eagle owl feather shaft is filled with a medullary foam structure, wherein the fiber layer in the middle section of the eagle owl feather shaft comprises a central axial fiber layup layer, transitional cross fiber layup layers are arranged on both sides of the central axial fiber layup layer, and surface circumferential fiber layup layers are arranged on the two layers of the transitional cross fiber layup layers away from the central axial fiber layup layer.

[0007] Preferably, the surface circumferential fiber layup layer comprises a plurality of unidirectional fiber layers, and a twill woven fiber layer is arranged on the outermost layer of the plurality of unidirectional fiber layers away from the transition cross fiber layup layer.

[0008] Preferably, the transitional cross-fiber stacking layer comprises multiple unidirectional fiber layers that are axially interlaced with each other, and the axial angle between each unidirectional fiber layer and the bionic fiber reinforced composite material tube meets the following formulas (1) and (2):

[0009]

[0010] Where: α i is the angle between the i-th unidirectional fiber layer and the axial direction of the bionic fiber reinforced composite material tube, i is an odd number, α j is the axial angle between the j-th unidirectional fiber layer and the bionic fiber reinforced composite material tube, j is an even number, and Y is the number of layers of the transitional cross fiber layup.

[0011] Preferably, the central axial fiber stacking layer includes multiple unidirectional fiber layers whose axial direction is the same as that of the bionic fiber reinforced composite material tube.

[0012] Preferably, the medullary foam structure is made of PMI foam.

[0013] Preferably, the number of layers in the central axial fiber layup layer, the transition cross fiber layup layer and the surface circumferential fiber layup layer conforms to the formula (3):

[0014]

[0015] Among them: X is the number of layers of the surface circumferential fiber layup layer, Y is the number of layers of the transition cross fiber layup layer, Z is the number of layers of the central axial fiber layup layer, and N is the total number of layers of the fiber layer in the middle section of the feather shaft of the imitation eagle owl.

[0016] Preferably, the cross-section of the bionic fiber reinforced composite material tube includes a rectangle or a circle.

[0017] According to a second aspect of an embodiment of the present invention, there is provided a bionic fiber reinforced composite material circular tube positioner, which is applied to the bionic fiber reinforced composite material tube described in the first aspect, and comprises a bionic fiber reinforced composite material tube with a circular cross-section, wherein positioning pins and connecting ears are respectively provided at both ends of the bionic fiber reinforced composite material tube.

[0018] According to a third aspect of an embodiment of the present invention, a bionic fiber reinforced composite rectangular tube positioner is provided, which is applied to the bionic fiber reinforced composite tube described in the first aspect, and is characterized in that it comprises a bionic fiber reinforced composite tube with a rectangular cross-section, and positioning pins and positioning hooks are respectively provided at both ends of the bionic fiber reinforced composite tube.

[0019] According to a fourth aspect of an embodiment of the present invention, there is provided a design method for a bionic fiber reinforced composite material tube, which is applied to the bionic fiber reinforced composite material tube described in the first aspect, comprising:

[0020] Step S10, performing bionic design based on the foam-like structure in the medulla of the middle section of the eagle owl feather shaft and the fiber structure in the cortex, and establishing a finite element model of a bionic fiber-reinforced composite material tube;

[0021] Step S20, defining model material parameters according to the bionic fiber layout mode and layout ratio and applying load according to actual working conditions;

[0022] Step S30, performing strength and stiffness calculation analysis on the finite element model of the bionic fiber reinforced composite material tube, and determining the ply thickness of the composite material tube according to the stiffness criterion;

[0023] Step S40, performing a tensile test and a bending test on the bionic fiber reinforced composite material plate to verify the mechanical properties of the bionic ply scheme;

[0024] Step S50, preparing a composite material tube according to the bionic design result, and testing and verifying the structural performance according to industry standards to obtain a final bionic fiber reinforced composite material tube model.

[0025] The beneficial effects of the present invention are:

[0026] (1) The present invention provides a bionic fiber reinforced composite material tube. Through bionic design thinking, the structure of the middle section of the feather shaft of an eagle owl is imitated, and a bionic gradient plying design of 3:6:11 is used for fiber laying in the inner PMI foam outer layer, thereby improving the bending and torsion resistance of the composite material tube under various complex working conditions.

[0027] (2) The present invention provides a bionic fiber reinforced composite material tube, wherein the ratio of fibers in each direction of the fiber reinforced composite material tube is approximately equal to the thickness ratio of the circumferential fibers, cross fibers, and axial fibers in the middle section of the eagle owl feather shaft, the number of plies of the surface circumferential fiber layer accounts for 15.4% of the total number of plies, the number of plies of the transition cross fiber layer accounts for 30.8% of the total number of plies, and the number of plies of the center axial fiber layer accounts for 53.8% of the total number of plies. Compared with traditional metal tubes, the specific stiffness and specific strength of the structure are significantly improved.

[0028] (3) The present invention provides a bionic fiber reinforced composite material tube, wherein the circumferential fiber layer on the surface of the fiber reinforced composite material tube is a combination of twill woven fibers and circumferential fibers, thereby suppressing the separation of the inner layer fibers and preventing the fibers from cracking when the composite material tube is bent under load.

[0029] (4) The present invention provides a bionic fiber reinforced composite material tube, wherein the transition cross fiber layer of the fiber reinforced composite material tube increases the torsional stiffness of the composite material tube, dissipates energy, and prevents structural damage by combining cross-angle fibers.

[0030] (5) The present invention provides a bionic fiber reinforced composite material tube, wherein the central axial fiber layer of the fiber reinforced composite material tube is aggregated by a large number of unidirectional fibers, thereby greatly improving the bending stiffness and ultimate strength of the composite material tube.

[0031] (6) The present invention provides a bionic fiber reinforced composite material tube, in which PMI foam is used as a support in the fiber reinforced composite material tube, thereby eliminating the preparation of steel molds in the traditional composite material molding process, improving the overall performance of the composite material tube while reducing the tube molding cost, and adopting a gradient bionic symmetrical laying structure along the radial direction of the composite material tube to avoid deformation during the curing process of the fiber reinforced composite material, thereby improving the structural performance of the composite material tube while enhancing the molding accuracy and molding stability.

[0032] (7) The present invention provides a bionic fiber reinforced composite material tube. Compared with a traditional metal tube, the composite material tube of the present invention reduces weight by 40-55%.

[0033] (8) The present invention provides a design method for a bionic fiber reinforced composite material tube, which optimizes the design of the bionic fiber layout scheme through the finite element method, greatly reduces the experimental cost and improves the structural performance.

[0034] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic structural diagram of a surface circumferential fiber layup layer in a bionic fiber reinforced composite material tube according to an exemplary embodiment.

[0036] Figure 2 It is a schematic structural diagram of a transitional cross-fiber layup layer in a bionic fiber reinforced composite material tube according to an exemplary embodiment.

[0037] Figure 3 It is a schematic structural diagram of a central axial fiber stacking layer in a bionic fiber reinforced composite material tube according to an exemplary embodiment.

[0038] Figure 4 It is a schematic structural diagram of a medullary foam structure in a bionic fiber reinforced composite material tube according to an exemplary embodiment.

[0039] Figure 5 The figure is a cross-sectional view of a bionic fiber reinforced composite material tube with a circular cross section according to an exemplary embodiment.

[0040] Figure 6 The figure is a cross-sectional view of a bionic fiber reinforced composite material tube with a rectangular cross section according to an exemplary embodiment.

[0041] Figure 7 It is a schematic structural diagram of a bionic fiber reinforced composite material circular tube positioner according to an exemplary embodiment.

[0042] Figure 8 It is a schematic structural diagram of a bionic fiber reinforced composite rectangular tube positioner according to an exemplary embodiment.

[0043] Fig. 9 The present invention is a flow chart of a method for designing a bionic fiber reinforced composite material tube according to an exemplary embodiment.

[0044] Wherein: 1-bionic fiber reinforced composite material tube, 2-positioning pin, 3-connecting single ear, 4-positioning hook, 11-twill woven fiber layer, 12-unidirectional fiber layer, 13-medullar foam structure. DETAILED DESCRIPTION

[0045] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0047] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] Embodiment 1

[0049] According to an exemplary embodiment, a bionic fiber reinforced composite material tube is shown, including a fiber layer in the middle section of an eagle owl feather shaft, the fiber layer in the middle section of the eagle owl feather shaft is filled with a medullary foam structure 13, the fiber layer in the middle section of the eagle owl feather shaft includes a central axial fiber layup layer, transition cross fiber layup layers are arranged on both sides of the central axial fiber layup layer, and surface circumferential fiber layup layers are arranged on the two transition cross fiber layup layers away from the central axial fiber layup layer. The specific structures of the above-mentioned parts will be introduced one by one below.

[0050] The fibers in the composite material tube of the present application are designed with bionic layout, and the axial fiber angle of the composite material tube is specified to be 0°, the circumferential fiber angle of the composite material tube is 90°, the clockwise twist along the axial direction is represented as a "+" fiber angle, and the counterclockwise twist along the axial direction is represented as a "-" fiber angle.

[0051] First, the surface circumferential fiber layup layer is introduced, such as Figure 1 As shown, the design is modeled after the circumferential fiber design of the cortical surface of the feather shaft of an eagle owl, including multiple layers of unidirectional fiber layers 12. The multiple layers of unidirectional fiber layers 12 are unidirectional fibers laid circumferentially. This part of the fiber is in contact with the transition cross-laying part, which inhibits the separation of the inner layer fibers and prevents the fiber cracking when the composite pipe is loaded and bent. The outermost layer of the multiple layers of unidirectional fiber layers 12 is arranged with a twill woven fiber layer 11 on the side away from the transition cross-fiber lay-up layer. The twill woven fiber layer 11 can enhance the toughness and stability of the surface of the composite pipe in all directions and improve the overall aesthetics.

[0052] The following is an introduction to the transitional cross-fiber layup, such as Figure 2 As shown, the cross-fiber design of the cortical side of the eagle owl feather shaft is imitated, including multiple unidirectional fiber layers 12 that are axially interlaced with each other, which can increase the torsional stiffness of the fiber-reinforced composite material tube, dissipate energy, and prevent structural damage. The axial angle between each unidirectional fiber layer (12) and the bionic fiber-reinforced composite material tube conforms to the formulas (1) and (2):

[0053]

[0054] Where: α i is the angle between the i-th unidirectional fiber layer and the axial direction of the bionic fiber reinforced composite material tube, i is an odd number, α j is the axial angle between the j-th unidirectional fiber layer and the bionic fiber reinforced composite material tube, j is an even number, and Y is the number of layers of the transitional cross fiber layup.

[0055] Next, let's introduce the central axial fiber stacking layer. Figure 3 As shown, it includes multiple unidirectional fiber layers 12 whose axial direction is the same as that of the bionic fiber reinforced composite material tube, thereby greatly improving the bending stiffness and ultimate strength of the fiber reinforced composite material tube.

[0056] This application adopts a laying strategy similar to the fiber thickness in each direction of the middle section of the eagle owl feather shaft, and maximizes the performance of the composite tube by changing the gradient of fibers in different directions. Therefore, the number of layers in the central axial fiber layup layer, the transition cross fiber layup layer and the surface circumferential fiber layup layer conforms to the formula (3):

[0057]

[0058] Among them: X is the number of layers of the surface circumferential fiber layup layer, Y is the number of layers of the transition cross fiber layup layer, Z is the number of layers of the central axial fiber layup layer, and N is the total number of layers of the fiber layer in the middle section of the feather shaft of the imitation eagle owl.

[0059] Finally, the foamy structure of the lower medulla is introduced13, such as Figure 4 As shown, PMI foam with high closed cell rate and relatively uniform pore size is used. Due to the characteristics of high compressive strength and stiffness, high temperature resistance, moisture and heat resistance, and strong dimensional stability, PMI foam can be used as a core material to complete co-curing with composite prepreg. PMI foam prevents axial fiber splitting and sudden load drop, and further toughens the composite pipe structure through interface bonding, crack deflection and crack shielding.

[0060] The cross section of the bionic fiber reinforced composite material tube 1 of the present application includes a rectangle or a circle. The bionic fiber reinforced composite material tube 1 with a circular cross section is as follows: Figure 5 As shown, the bionic fiber reinforced composite material tube 1 with a rectangular cross section is as shown in Figure 6 shown.

[0061] Embodiment 2

[0062] Figure 7 According to an exemplary embodiment, a bionic fiber reinforced composite circular tube positioner is shown, comprising a bionic fiber reinforced composite tube 1 with a circular cross-section, and positioning pins 2 and connecting ears 3 are installed at both ends of the bionic fiber reinforced composite tube 1 through a gluing process.

[0063] Embodiment 3

[0064] Figure 8 According to an exemplary embodiment, a bionic fiber reinforced composite rectangular tube positioner is shown, which includes a bionic fiber reinforced composite tube 1 with a rectangular cross-section, and positioning pins 2 and positioning hooks 4 are installed at both ends of the bionic fiber reinforced composite tube 1 through a gluing process.

[0065] Embodiment 4

[0066] Fig. 9 A design method for a bionic fiber reinforced composite material tube according to an exemplary embodiment includes:

[0067] Step S10, performing bionic design based on the foam-like structure in the medulla of the middle section of the eagle owl feather shaft and the fiber structure in the cortex, and establishing a finite element model of a bionic fiber reinforced composite material tube, wherein:

[0068] Shell elements are used to establish the fiber reinforced composite tube, and solid elements combined with homogenization theory are used to establish the internal PMI foam. The finite element model of the bionic fiber reinforced composite tube is connected with the locating pins on both sides and the connecting single ear / locating hook through binding constraints.

[0069] Step S20, defining model material parameters according to the bionic fiber layout mode and layout ratio and applying load according to actual working conditions, wherein:

[0070] Since fiber-reinforced composite tubes will be subjected to a variety of complex working conditions such as tension, compression, bending, torsion and vibration during service, their structure is similar to the feather shaft structure. Therefore, the fiber-reinforced composite tubes are designed to imitate the mid-section structure of the eagle owl feather shaft to improve the overall performance of the tube.

[0071] Step S30, performing strength and stiffness calculation analysis on the finite element model of the bionic fiber reinforced composite material tube, and determining the ply thickness of the composite material tube according to the stiffness criterion, wherein:

[0072] The strength of the bionic fiber reinforced composite positioner under the condition of equal thickness is much higher than that of the original metal positioner, while the stiffness is lower than that of the original metal positioner. The ply of the bionic fiber reinforced composite positioner is further thickened, and the thickness of the bionic fiber ply of the fiber reinforced composite positioner is optimized according to the stiffness criterion of the original metal positioner.

[0073] Step S40, performing a tensile test and a bending test on the bionic fiber reinforced composite material plate to check the mechanical properties of the bionic ply scheme, wherein:

[0074] After determining the bionic fiber reinforced composite material laying plan and thickness, the tensile, bending and other properties of the bionic fiber reinforced composite material sheet are compared with those of the original metal sheet to verify and verify that the mechanical properties of the bionic fiber reinforced composite material sheet are better than those of the original metal sheet.

[0075] Step S50, preparing a composite material tube according to the bionic design result, and testing and verifying the structural performance according to industry standards to obtain a final bionic fiber reinforced composite material tube model, wherein:

[0076] Prepare a bionic fiber reinforced composite material positioner obtained by the bionic design method of a fiber reinforced composite material tube described in the present invention, lay the above-mentioned fiber reinforced composite material on the inner PMI foam outer layer, and complete the curing molding. This molding method can effectively avoid residual stress and warping deformation during the curing process of the fiber reinforced composite material, eliminate the preparation of steel molds in the traditional composite material molding process, improve the overall performance of the positioner while reducing the molding cost of the positioner. Compared with the existing metal positioner, it effectively reduces the weight by 46%. The cured bionic fiber reinforced composite material positioner is connected to the positioning pins and positioning hooks at both ends through a gluing process, and the performance of the bionic fiber reinforced composite material positioner is verified according to industry standards to obtain the final bionic fiber reinforced composite material tube model.

[0077] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily realized. Therefore, without departing from the general concept defined by the claims and equivalent scope, the present invention is not limited to the specific details and the illustrations shown and described here.

Claims

1. A bionic fiber reinforced composite material tube, characterized in that: The invention comprises a fiber layer in the middle section of an eagle owl feather shaft, wherein the fiber layer in the middle section of the eagle owl feather shaft is filled with a medullary foam structure (13), wherein the fiber layer in the middle section of the eagle owl feather shaft comprises a central axial fiber layup layer, wherein transitional cross fiber layup layers are arranged on both sides of the central axial fiber layup layer, and surface circumferential fiber layup layers are arranged on the sides of the two transitional cross fiber layup layers away from the central axial fiber layup layer.

2. The bionic fiber reinforced composite material tube according to claim 1, characterized in that: The surface circumferential fiber layup layer comprises a plurality of unidirectional fiber layers (12), and a twill woven fiber layer (11) is arranged on the outermost layer of the plurality of unidirectional fiber layers (12) on a side away from the transition cross fiber layup layer.

3. A bionic fiber reinforced composite material tube according to claim 1 or 2, characterized in that: The transitional cross-fiber stacking layer comprises a plurality of unidirectional fiber layers (12) that are axially interlaced with each other, and the axial angle between each unidirectional fiber layer (12) and the bionic fiber reinforced composite material tube conforms to the formulas (1) and (2): Where: α i is the angle between the i-th unidirectional fiber layer and the axial direction of the bionic fiber reinforced composite material tube, i is an odd number, α j is the axial angle between the j-th unidirectional fiber layer and the bionic fiber reinforced composite material tube, j is an even number, and Y is the number of layers of the transitional cross fiber layup.

4. The bionic fiber reinforced composite material tube according to claim 3, characterized in that: The central axial fiber stacking layer comprises a plurality of unidirectional fiber layers (12) whose axial direction is the same as that of the bionic fiber reinforced composite material tube.

5. The bionic fiber reinforced composite material tube according to claim 4, characterized in that: The medullary foam structure (13) is made of PMI foam.

6. The bionic fiber reinforced composite material tube according to claim 4 or 5, characterized in that: The number of layers in the central axial fiber layup layer, the transition cross fiber layup layer and the surface circumferential fiber layup layer conforms to the formula (3): Wherein: X is the number of layers of the surface circumferential fiber layup layer, Y is the number of layers of the transition cross fiber layup layer, Z is the number of layers of the central axial fiber layup layer, and N is the total number of layers of the fiber layer in the middle section of the feather shaft of the eagle owl.

7. The bionic fiber reinforced composite material tube according to claim 6, characterized in that: The cross section of the bionic fiber reinforced composite material tube (1) includes a rectangle or a circle.

8. A bionic fiber reinforced composite material circular tube positioner, applied to the bionic fiber reinforced composite material tube according to any one of claims 1 to 7, characterized in that: It comprises a bionic fiber reinforced composite material tube (1) with a circular cross section, wherein two ends of the bionic fiber reinforced composite material tube (1) are respectively provided with a positioning pin (2) and a connecting single ear (3).

9. A bionic fiber reinforced composite rectangular tube positioner, applied to the bionic fiber reinforced composite tube according to any one of claims 1 to 7, characterized in that: It comprises a bionic fiber reinforced composite material tube (1) with a rectangular cross section, wherein two ends of the bionic fiber reinforced composite material tube (1) are respectively provided with a positioning pin (2) and a positioning hook (4).

10. A method for designing a bionic fiber reinforced composite material tube, applied to the bionic fiber reinforced composite material tube according to any one of claims 1 to 7, characterized in that: include: Step S10, performing bionic design based on the foam-like structure in the medulla of the middle section of the eagle owl feather shaft and the fiber structure in the cortex, and establishing a finite element model of a bionic fiber-reinforced composite material tube; Step S20, defining model material parameters according to the bionic fiber layout mode and layout ratio and applying load according to actual working conditions; Step S30, performing strength and stiffness calculation analysis on the finite element model of the bionic fiber reinforced composite material tube, and determining the ply thickness of the composite material tube according to the stiffness criterion; Step S40, performing a tensile test and a bending test on the bionic fiber reinforced composite material plate to verify the mechanical properties of the bionic ply scheme; Step S50, preparing a composite material tube according to the bionic design result, and testing and verifying the structural performance according to industry standards to obtain a final bionic fiber reinforced composite material tube model.

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