Layering structure with spirally-arranged fibers, super-spiral composite material and design method

Abstract

The invention discloses a fiber spiral laying layer structure, a super-spiral composite material and a design method, the fiber spiral laying layer structure comprises a plurality of fiber laying layers with different areas formed by different fiber lengths, and the fiber layers are periodically and spirally arranged in the laying layer direction to form a forward spiral unit [0 / theta / 2 theta / ... / 180-theta / 180]; the outer side of each laying layer is further nested with a layer of regular hexagonal frame, the laying angle of the externally nested fiber frame layer is 180 degrees-theta, and a reverse spiral unit [180 / 180-theta / ... / 2 theta / theta / 0] is formed. According to the composite material, due to the fact that the areas of the fiber laying layers are different and the laying layer angles between the fiber laying layers are different, when the material is subjected to external loads, bending deformation between the different fiber laying layers, friction between the layers, rotation between the fiber laying layers, stretching of fibers in the fiber laying layers, pulling-out of the fibers and layering absorb part of energy; meanwhile, interlayer shear stress concentration is relieved, and continuous mechanical property transition is formed. And the layering phenomenon is relieved by optimizing the layering structure, so that the mechanical property is improved.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and in particular to a fiber spirally laid layer structure, a super spiral composite material and a design method. Background Art

[0002] Fiber-reinforced resin-based composite materials have been widely used in defense, aviation and other fields due to their high specific strength, large specific modulus, strong designability of material properties, good corrosion resistance and durability. The many advantages of carbon fiber reinforced resin-based composite materials also include light weight, high strength, fatigue resistance, corrosion resistance, flexible design possibilities and excellent impact resistance. These advantages make composite materials an indispensable material in the field of modern science and technology, significantly improving performance, durability and economy, while also meeting the requirements of development in various fields and promoting technological innovation and development.

[0003] Traditional composite laminates mostly adopt uniform ply or simple angle stacking design, which has the following problems: high risk of delamination, concentrated interlaminar shear stress that easily leads to interface peeling, limited structural stiffness, uniform-sized honeycomb or laminated structures are difficult to adapt to complex load distribution, poor process compatibility, and difficulty in secondary processing after thick plate forming, etc. In the prior art, although there have been studies on gradient spiral structures, there has been no combination of regular hexagonal size gradient and multi-angle spiral arrangement to achieve interlaminar stress optimization. Summary of the invention

[0004] The purpose of the present invention is to provide a fiber spirally laid ply structure, a super spiral composite material and a design method to address the problems existing in the prior art, so as to overcome the problems that traditional fiber reinforced composite materials are difficult to meet the requirements of high strength and high toughness at the same time, and are prone to debonding of the resin interface between layers and stratification failure when subjected to load.

[0005] To achieve the above object, the technical solution adopted by the present invention is: In a first aspect, a fiber spirally laid ply structure is provided, comprising a plurality of fiber plies having different fiber lengths and areas, the plurality of fiber plies being arranged along a common central axis, the sizes of the plurality of fiber plies increasing layer by layer from the center to the edge, and the thickness gradually becoming thinner near the free boundary; The fiber plies are arranged in a periodic spiral along the ply direction, and there is a periodically changing spiral angle between adjacent fiber plies. Assuming the spiral angle is θ, the spiral angles of several fiber plies form a forward spiral unit [0 / θ / 2θ / ... / 180-θ / 180].

[0006] The fiber spirally laid ply structure improves the structure of each ply so that the areas of each fiber ply and the ply angles between the fiber plies are different. When the material is subjected to external loads, the bending deformation between different fiber plies, the friction between the plies, the rotation between the fiber plies, the stretching of the fibers within the fiber plies, the pulling out of the fibers and the stratification can all absorb energy, thereby reducing the shear stress concentration between the plies and forming a continuous transition of mechanical properties. By optimizing the ply structure, the stratification phenomenon is reduced, thereby improving its mechanical properties.

[0007] Furthermore, a fiber frame layer is nested on the periphery of each layer of the fiber ply, and the total area of ​​each layer of the fiber ply is the same as that of the fiber frame layer.

[0008] Furthermore, the helical angle of the fiber framework layer is 180°-θ, and the helical angles of several layers of the fiber framework layer form a reverse helical unit [180 / 180-θ / ... / 2θ / θ / 0].

[0009] By nesting a fiber frame on the periphery of the fiber ply, the outer contour area of ​​each layer is made basically the same. This super-helical composite ply structure that is nested inside and outside and spirally formed layer by layer has excellent mechanical properties, can effectively weaken the anisotropy within the composite layer, and reduce interface stratification damage; when the material is subjected to impact load, the crack expands along the spiral fiber interface to form a three-dimensional spiral path, increasing the surface area for crack expansion and dissipating energy. The crack mainly expands in a spiral shape between the chitin fibers to avoid penetrating the entire structure and causing fatal damage. At the same time, it reduces the shear stress concentration between layers and forms a continuous transition of mechanical properties.

[0010] Furthermore, the spiral angle θ has a value range of 0° to 90°, and the spiral period is an integer multiple of 180°.

[0011] Furthermore, a misalignment angle α is provided between the fiber ply and the fiber frame layer, and the reverse spiral unit of the fiber frame layer is [180+α / 180-θ+α / ... / 2θ+α / θ+α / 0+α].

[0012] Furthermore, the fiber ply and the fiber frame layer are both regular polygonal structures.

[0013] Furthermore, the fibers of the laminate structure are one or more combinations of carbon fiber, glass fiber, basalt fiber, and aramid fiber.

[0014] According to a second aspect, a superhelical composite material with spirally laid fibers is provided, wherein the superhelical composite material comprises a plurality of fiber layers stacked in parallel with each other, each fiber layer is deflected at an angle relative to the next layer, and the constant angle difference between adjacent fiber layers forms a rotation period of 180°; the fiber layer comprises an embedded regular polygonal fiber ply and an externally nested regular polygonal fiber frame layer.

[0015] The cracks of the super-helical composite material extend along the interface of the spiral fibers, forming a three-dimensional spiral path, increasing the crack extension surface area and dissipating energy; the cracks mainly extend in a spiral shape between the fibers, avoiding penetrating the entire structure, reducing the concentration of interlayer shear stress, and forming a continuous transition of mechanical properties. This type of super-helical composite material is suitable for the lightweight, high-strength and high-toughness requirements in the fields of aerospace, national defense, and automobiles.

[0016] Furthermore, it also includes a composite laminate made from a plurality of the super-helical composite materials.

[0017] In a third aspect, a method for designing a super-helical composite material ply structure with spirally laid fibers is provided, the method comprising the following steps: Constructing a plurality of fiber plies with different areas formed by fibers of different lengths, wherein the fiber plies are regular polygons; Arrange a plurality of the fiber layers in a periodic spiral along the layer direction, with an initial angle of 0°, and deflect each layer by an angle of θ in turn; A regular polygonal fiber frame layer is nested outside each regular polygonal fiber ply so that the total area of ​​each ply is the same, and the laying angle of the externally nested fiber frame layer is 180°-θ to form the ply structure.

[0018] This design method is based on the lightweight and high-strength characteristics of the periodic regional fiber arrangement structure inside the mantis shrimp knuckles. It integrates the bionic design concept into the layup design of traditional composite laminates, providing a design method that can not only improve the out-of-plane mechanical properties of composite laminates, but also effectively weaken the in-plane anisotropy of composite laminates and reduce interface delamination damage.

[0019] Compared with the prior art, the beneficial effects of the present invention are: 1. The fiber spirally laid ply structure improves the structure of each ply, and reduces the stratification phenomenon by optimizing the ply structure, thereby improving its mechanical properties. The areas of each fiber ply are different, and the ply angles between the fiber layers are different. When the material is subjected to external loads, the bending deformation between different fiber plies, the friction between layers, the rotation between fiber plies, the fiber stretching in the fiber ply, the fiber pulling out and stratification can all absorb energy, reduce the shear stress concentration between layers, and form a continuous transition of mechanical properties; 2. The super-spiral composite material ply structure formed by nesting a fiber frame on the periphery of the fiber ply has excellent mechanical properties, can effectively weaken the anisotropy within the composite material layer, and reduce interface stratification damage; when the material is subjected to impact loads, cracks extend along the spiral fiber interface. , forming a three-dimensional spiral path, increasing the surface area for crack expansion, dissipating energy, the crack mainly expands in a spiral shape between the chitin fibers, avoiding penetrating the entire structure and causing fatal damage; 3. The super-helical composite material crack expands along the spiral fiber interface, forming a three-dimensional spiral path, increasing the crack expansion surface area, and dissipating energy; the crack mainly expands in a spiral shape between the fibers, avoiding penetrating the entire structure, reducing interlaminar shear stress concentration, and forming a continuous transition of mechanical properties; 4. This design method is based on the lightweight and high-strength characteristics of the periodic regional fiber arrangement structure inside the mantis shrimp knuckle stick, and incorporates the bionic design concept into the traditional laminate design of composite material laminates, providing a design method that not only improves the out-of-plane mechanical properties of composite laminates, but also effectively weakens the in-plane anisotropy of composite laminates and reduces interface delamination damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of a regular hexagonal fiber spiral unit embedded in a fiber spirally laid layer structure of the present invention; Figure 2 It is a front view of the regular hexagonal fiber spiral unit embedded in the ply structure of the present invention; Figure 3 A top view of a regular hexagonal fiber spiral unit embedded in the ply structure of the present invention; Figure 4 It is a schematic diagram of the structure of the regular hexagonal framework fiber spiral unit nested outside the ply structure of the present invention; Figure 5 It is a front view of the regular hexagonal framework fiber spiral unit nested outside the ply structure of the present invention; Figure 6 A top view of the regular hexagonal framework fiber spiral unit nested outside the ply structure of the present invention; Figure 7 A bottom view of the regular hexagonal framework fiber spiral unit nested outside the ply structure of the present invention; Figure 8 A schematic diagram of a superhelical combination structure is provided for Example 2 of the present invention; Fig. 9 A front view of a superhelical composite structure is provided for Example 2 of the present invention; Fig.10 A top view of a superhelical composite structure is provided for Example 2 of the present invention; Fig.11 A bottom view of a superhelical combination structure is provided for Example 2 of the present invention; Fig.12 A relationship diagram of the misalignment angle α between the forward spiral group and the reverse spiral group provided in an embodiment of the present invention; In the figure: 1. Fiber layup; 2. Fiber frame layer; 3. Super helical composite material. DETAILED DESCRIPTION

[0021] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0022] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "middle", "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the 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 direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Example 1

[0023] A ply structure with spirally laid fibers is provided, such as Figure 1 to Figure 3 As shown, it comprises a plurality of fiber plies 1 with different fiber lengths and areas, the plurality of fiber plies 1 are arranged along a central axis, the sizes of the plurality of fiber plies 1 increase layer by layer from the center to the edge, and the thickness gradually becomes thinner near the free boundary; The fiber plies 1 are arranged in a periodic spiral along the ply direction, and there is a periodically changing spiral angle between adjacent fiber plies 1. Assuming the spiral angle is θ, the spiral angles of several fiber plies form a forward spiral unit [0 / θ / 2θ / ... / 180-θ / 180].

[0024] The fiber spirally laid ply structure improves the structure of each ply so that the areas of each fiber ply and the ply angles between the fiber plies are different. When the material is subjected to external loads, the bending deformation between different fiber plies, the friction between the plies, the rotation between the fiber plies, the stretching of the fibers within the fiber plies, the pulling out of the fibers and the stratification can all absorb energy, thereby reducing the shear stress concentration between the plies and forming a continuous transition of mechanical properties. By optimizing the ply structure, the stratification phenomenon is reduced, thereby improving its mechanical properties.

[0025] The fiber ply of the ply structure is different from the conventional fiber layer structure. The fiber lengths used in each layer of the fiber ply are different, and the area of ​​the layer is also different, forming a Figure 2 The layered structure with a gradually increasing area (middle perspective) means that for the entire current laminate structure, the thickness becomes thinner closer to the edge.

[0026] These fiber layers stacked layer by layer have a common central axis, and are rotated layer by layer with the central axis as the rotation center axis, so that each layer is deflected by a fixed angle relative to the next layer, thereby forming a spiral layout structure that deflects layer by layer from bottom to top and has a varying area.

[0027] Further, combined with Figures 4 to 7 As shown, a fiber frame layer 2 is nested on the periphery of each layer of the fiber ply 1, and the total area of ​​each layer of the fiber ply 1 and the fiber frame layer 2 is the same.

[0028] By nesting a fiber frame on the periphery of the fiber ply 1, the outer contour area of ​​each layer is made basically the same. This super-helical composite ply structure that is nested inside and outside and spirally formed layer by layer has excellent mechanical properties, can effectively weaken the anisotropy within the composite layer, and reduce interface stratification damage; when the material is subjected to impact load, the crack expands along the spiral fiber interface to form a three-dimensional spiral path, increasing the surface area for crack expansion and dissipating energy. The crack mainly expands in a spiral shape between the chitin fibers to avoid penetrating the entire structure and causing fatal damage. At the same time, it reduces the shear stress concentration between layers and forms a continuous transition of mechanical properties.

[0029] In addition to the above-mentioned advantages, this laminate structure with an internal fiber laminate 1 and an external fiber frame layer 2 also solves the complex operational problems of the current technology for improving the mechanical properties of composite laminates, and provides a constructive basis and effective suggestions for the design and manufacture of composite laminates.

[0030] In this fiber spirally laid structure, each layer is tilted (deflected) at a certain angle relative to the next layer, and this constant angle difference between adjacent layers eventually forms a rotation period of 180°, thereby forming a characteristic wavelength and a super spiral layer; wherein the laying directions of each fiber ply are not the same, and the fiber layers with the same layer sequence in each of the fiber ply groups are periodically spirally laid along the laying direction.

[0031] Specifically, the spiral angle between adjacent fiber plies is θ, and the spiral angles of several fiber plies form a forward spiral unit (or a forward spiral group) [0 / θ / 2θ / ... / 180-θ / 180]; the spiral angle of the fiber frame layer is 180°-θ, and the spiral angles of several layers of the fiber frame layers form a reverse spiral unit (or a reverse spiral group) [180 / 180-θ / ... / 2θ / θ / 0].

[0032] Through this regular stacking and rotation, a periodic super-helical arrangement structure can be formed. This periodic regional fiber arrangement structure has the characteristics of light weight and high strength. It can overcome the problem that traditional fiber-reinforced composite materials are difficult to meet the requirements of high strength and high toughness at the same time, as well as the problem of debonding and stratification damage at the resin interface between layers when subjected to load. It can be widely used in the field of engineering technology.

[0033] Furthermore, the spiral angle θ has a value range of 0° to 90°, and the spiral period is an integer multiple of 180°.

[0034] Furthermore, a misalignment angle α is provided between the fiber ply and the fiber frame layer, and the reverse spiral unit of the fiber frame layer is [180+α / 180-θ+α / ... / 2θ+α / θ+α / 0+α]. That is to say, different reverse spiral units can be obtained by changing the misalignment angle α between the fiber ply and the fiber frame layer. Such adjustment can also improve the flexibility and versatility of the composite ply structure, so as to deduce and produce composite materials with different layered spirals.

[0035] Furthermore, the fiber ply and the fiber frame layer are both regular polygonal structures. In this embodiment, the preferred structure is a regular hexagonal structure, the fiber ply is a regular hexagonal fiber ply, and the fiber frame layer is a regular hexagonal frame, and the two are nested with each other.

[0036] Furthermore, the fibers used in the fiber ply and the fiber frame layer may be one or a combination of carbon fiber, glass fiber, basalt fiber, and aramid fiber. Example 2

[0037] This embodiment provides a super-helical composite material with spirally laid fibers, combined with Figure 8 to Figure 11As shown, the super-helical composite material 3 is based on the fiber spirally laid ply structure described in Example 1, and the super-helical composite material 3 includes a plurality of fiber layers stacked in parallel with each other, each fiber layer is deflected by an angle relative to the next layer, and the constant angle difference between adjacent fiber layers forms a rotation period of 180°; the fiber layer includes an embedded regular polygonal fiber ply 1 and an externally nested regular polygonal fiber frame layer 2.

[0038] The super-helical composite material of the above structure has the following properties: the cracks propagate along the interface of the spiral fibers, forming a three-dimensional spiral path, increasing the crack propagation surface area and dissipating energy; the cracks mainly propagate in a spiral shape between the fibers, avoiding penetrating the entire structure, reducing the concentration of interlayer shear stress, and forming a continuous transition of mechanical properties. This type of super-helical composite material is suitable for the lightweight, high-strength and high-toughness requirements in the fields of aerospace, national defense, and automobiles.

[0039] Furthermore, this type of super-helical composite material can be used to make composite laminates, which optimizes shear stress, has a lower risk of delamination, is not easy to peel off at the interface, is not limited by structural stiffness, and has good process compatibility, thereby reducing the difficulty of making the composite laminates and allowing secondary processing after the plates are formed.

[0040] Furthermore, the resin matrix of the superhelical composite material is a thermosetting resin or a thermoplastic resin. Example 3

[0041] This embodiment provides a design method for a super-helical composite material ply structure with spirally laid fibers.

[0042] Traditional composite laminates mostly adopt uniform ply or simple angle stacking design, which has obvious problems, such as high risk of delamination, concentrated shear stress between layers, which easily leads to interface peeling, limited structural stiffness, uniform size honeycomb or laminated structure is difficult to adapt to complex load distribution, poor process compatibility, and difficulty in secondary processing after thick plate forming. Although there are studies on gradient spiral structures in the prior art, the optimization of interlayer stress has not yet been achieved by combining the size gradient of regular hexagons with multi-angle spiral arrangement.

[0043] Mantis shrimp can generate an impact force of up to 700N in a very short time. This impact force can not only shatter the exoskeleton of the prey, but also generate cavitation bubbles. When the bubbles burst, they will generate high-frequency stress waves, but they can withstand thousands of impacts without catastrophic damage. The excellent damage resistance of mantis shrimp knuckles comes from its complex multi-level structure, including highly mineralized surfaces, spirally arranged biological fibers, and gradient-changing periodic regions. The spiral structure of the mantis shrimp periodic region is a highly ordered microstructure of layered spiral arrangement. Its chitin fibers form a thin layer with a protein matrix. The direction of each layer of fibers rotates at a fixed angle relative to the adjacent layers, and the layers are stacked layer by layer to form a spiral gradient. The overall appearance is a continuous spiral arrangement similar to a "spiral staircase", with hundreds of layers. This design method studies and analyzes this structure of mantis shrimp, and forms a super-helical design by changing the laying angle of the fiber layer and the area of ​​the hexagonal face of a single fiber layer.

[0044] The design method comprises the following steps: Constructing a plurality of fiber plies with different areas formed by fibers of different lengths, wherein the fiber plies are regular hexagons; Arrange a plurality of the fiber plies in a periodic spiral along the ply direction, with an initial angle of 0°, and rotate each layer clockwise or counterclockwise about the central axis of the regular hexagon, and deflect by an angle θ in turn, and the angle between the sides of adjacent regular hexagonal fiber plies is an angle θ; obtain a forward spiral unit [0 / θ / 2θ / ... / 180-θ / 180]; A regular polygonal fiber frame layer is nested outside each regular polygonal fiber layer, so that the total area of ​​each layer is the same, and the laying angle of the external nested fiber frame layer is 180°-θ, obtaining a reverse spiral unit [180 / 180-θ / ... / 2θ / θ / 0]; The laminate structure is obtained by nesting the internal forward spiral unit [0 / θ / 2θ / ... / 180-θ / 180] with the external reverse spiral unit [180 / 180-θ / ... / 2θ / θ / 0]. The design of this optimized laminate structure can well alleviate the delamination phenomenon and improve its mechanical properties.

[0045] This design method is based on the light-weight and high-strength characteristics of the periodic regional fiber arrangement structure inside the mantis shrimp knuckle stick. It incorporates the bionic design concept into the traditional laminate design of composite laminates, providing a method that not only improves the out-of-plane mechanical properties of composite laminates, but also effectively weakens the in-plane anisotropy of composite laminates and reduces interface delamination damage. When the material is subjected to impact loads, the cracks extend along the spiral fiber interface to form a three-dimensional spiral path, increase the surface area of ​​crack extension, dissipate energy, and the cracks mainly extend in a spiral shape between the chitin fibers to avoid penetrating the entire structure and causing fatal damage. At the same time, it reduces the shear stress concentration between the layers and forms a continuous transition of mechanical properties.

[0046] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A ply structure with spirally laid fibers, characterized in that: It comprises a plurality of fiber plies with different fiber lengths and areas, the plurality of fiber plies are arranged along a central axis, the size of the plurality of fiber plies increases layer by layer from the center to the edge, and the thickness gradually becomes thinner near the free boundary; The fiber plies are arranged in a periodic spiral along the ply direction, and there is a periodically changing spiral angle between adjacent fiber plies. Assuming the spiral angle is θ, the spiral angles of several fiber plies form a forward spiral unit [0 / θ / 2θ / ... / 180-θ / 180].

2. The fiber spirally laid ply structure according to claim 1, characterized in that: A fiber frame layer is nested on the periphery of each layer of the fiber ply respectively, and the total area of ​​each layer of the fiber ply is the same as that of the fiber frame layer.

3. The fiber spirally laid ply structure according to claim 2, characterized in that: The helical turning angle of the fiber framework layer is 180°-θ, and the helical turning angles of several layers of the fiber framework layer form a reverse helical unit [180 / 180-θ / ... / 2θ / θ / 0].

4. The fiber spirally laid ply structure according to claim 1, characterized in that: The spiral angle θ has a value range of 0° to 90°, and the spiral period is an integer multiple of 180°.

5. The spirally laid fiber ply structure according to claim 2, characterized in that: There is a misalignment angle α between the fiber laying layer and the fiber frame layer, and the reverse spiral unit of the fiber frame layer is [180+α / 180-θ+α / ... / 2θ+α / θ+α / 0+α].

6. The spirally laid fiber ply structure according to claim 2, characterized in that: The fiber ply and the fiber frame layer are both regular polygonal structures.

7. The spirally laid fiber ply structure according to claim 1, characterized in that: The fibers of the laminate structure are one or more combinations of carbon fiber, glass fiber, basalt fiber and aramid fiber.

8. A super-helical composite material with spirally laid fibers, characterized in that: The super-helical composite material is based on a fiber spirally laid ply structure as described in any one of claims 1 to 7, and the super-helical composite material comprises a plurality of fiber plies stacked in parallel with each other, each fiber ply is deflected at an angle relative to the next layer, and the constant angle difference between adjacent fiber plies forms a rotation period of 180°; the fiber ply comprises an embedded regular polygonal fiber ply and an externally nested regular polygonal fiber frame layer.

9. The super-helical composite material with spirally laid fibers according to claim 8, characterized in that: Also included is a composite laminate made from a plurality of the super-helical composite materials.

10. The method for designing a ply structure of spirally laid fibers according to any one of claims 1 to 7, characterized in that: The design method comprises the following steps: Constructing a plurality of fiber plies with different areas formed by fibers of different lengths, wherein the fiber plies are regular polygons; Arrange a plurality of the fiber layers in a periodic spiral along the layer direction, with an initial angle of 0°, and deflect each layer by an angle of θ in turn; A regular polygonal fiber frame layer is nested outside each regular polygonal fiber ply so that the total area of ​​each ply is the same, and the laying angle of the externally nested fiber frame layer is 180°-θ to form the ply structure.

Images