Composite material grid structure forming method

Abstract

The invention relates to the technical field of composite material forming, and provides a composite material grid structure forming method which comprises the following steps: uniformly and annularly paving a plurality of longitudinal ribs on the outer side surface of a cylindrical mold in the circumferential direction; in the axial direction of the cylindrical mold, strip ring ribs are sequentially laid at intervals; repeating the previous two steps until a preset laying layer number is reached, and forming a grid structure; in the laying process of each layer of ring ribs of the ring rib channel, breakpoints are sequentially formed on each layer of ring ribs from inside to outside according to a preset breakpoint laying mode; and the breakpoints of two adjacent layers of ring ribs are distributed in a staggered manner. Therefore, breakpoint distribution is optimized, breakpoints of two adjacent layers do not coincide, the situation that the breakpoints are concentrated on a certain layer, and the mechanical property of the whole grid structure is damaged is avoided; and meanwhile, the situation that breakpoints are concentrated in the same node is avoided. According to the breakpoint distribution mode, control over the total thickness of the nodes is achieved, meanwhile, concentrated distribution of breakpoints is avoided, and the mechanical property of the grid structure is optimized.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material molding, and in particular relates to a composite material grid structure molding method. Background Art

[0002] Composite grid structure is a composite material structure with high specific strength, high specific stiffness, and strong bending resistance. It is widely used in the aerospace field.

[0003] The grid structure includes multiple layers of materials, each layer is composed of multiple longitudinal and annular reinforcements, and the intersection of the longitudinal and annular reinforcements forms nodes. Compared with other parts (longitudinal reinforcement layer and annular reinforcement layer), the number of material layers at the node position is more, making the node position a weak point and easily damaged under the action of external forces. Therefore, in order to avoid excessive thickness at the node, it is necessary to form breakpoints at certain node positions during the laying process to reduce the total thickness of the node and optimize the mechanical properties.

[0004] See also Figure 1 and 2 In order to avoid misoperation during the laying process, the existing breakpoints are usually set in one or several layers. Although this method can avoid the error of increasing or decreasing the breakpoints, the centralized setting of breakpoints will cause the mechanical properties of the layer to be seriously reduced, which has a great impact on the overall mechanical properties and affects the stability of product performance.

[0005] In summary, the prior art obviously has inconveniences and defects in practical use, so it is necessary to improve it. Summary of the invention

[0006] In view of the above-mentioned defects, the present invention mainly provides a composite material grid structure forming method to solve the technical problem that the concentrated arrangement of breakpoints affects the stability of the overall mechanical properties.

[0007] In order to solve the above problems, the present invention provides a composite material grid structure forming method, comprising the following steps:

[0008] S1, using fiber bundles, laying multiple longitudinal ribs along the axial direction on the outer surface of the cylindrical mold, and each longitudinal rib is evenly arranged around the central axis of the mold;

[0009] S2, using fiber bundles, laying multiple annular ribs in sequence and at intervals along the axial direction of the cylindrical mold; each annular rib is arranged around the circumference of the mold and intersects with each longitudinal rib in sequence;

[0010] S3, repeating steps S1 and S2 until a predetermined number of laying layers is reached to form the grid structure;

[0011] The grid structure has a plurality of longitudinal reinforcements and annular reinforcements; the intersections of the longitudinal reinforcements and the annular reinforcements form nodes; each node includes multiple layers of cross-stacked longitudinal reinforcements and annular reinforcements; the number of annular reinforcement layers of the annular reinforcement is denoted as A;

[0012] During the laying process of each layer of ring reinforcement of each ring reinforcement channel, breakpoints are formed on each layer of ring reinforcement from the inside to the outside in accordance with a predetermined breakpoint layout; the breakpoints on any layer of ring reinforcement of each ring reinforcement channel are staggered with the breakpoints of the adjacent layer of ring reinforcement.

[0013] According to the composite material grid structure forming method of the present invention, in the step S3, the breakpoint arrangement of each ring rib includes the following steps:

[0014] Z1, determine the process parameters;

[0015] The process parameters include the continuous ratio H of the fiber bundles, the number C of longitudinal reinforcements in step S1; the number A of ring reinforcement layers and the number E of nodes in each ring reinforcement in step S3; the number E of nodes = the number C of longitudinal reinforcements;

[0016] Z2, determine the ring reinforcement continuity ratio B = [1-2*(1-H)]*100%;

[0017] Z3, determine the number of breakpoints per layer That is, the calculation result is rounded down to an integer;

[0018] Z4, determine the distribution of breakpoints on the first layer of ring reinforcement;

[0019] The distribution method of the breakpoints is: select a node of the ring reinforcement layer as the initial breakpoint, and set the remaining breakpoints in order with the same number of nodes;

[0020] Z5, determine the distribution of breakpoints on the next layer of ring reinforcement;

[0021] The distribution of the breakpoints on the ring reinforcement of this layer is as follows: the initial breakpoint of this layer is offset by one node from the initial breakpoint of the previous layer; the remaining breakpoints are set in the same manner as in step Z4;

[0022] Z6, repeat step Z5 until a cycle of ring reinforcement laying is completed; the number of layers of ring reinforcement in each cycle is

[0023] Z7, according to the number of ring reinforcement layers A, determine the number of cycles of step Z6

[0024] When the calculation result of A / G is not an integer, step Z5 is repeated in the last cycle until the laying of the ring reinforcement of the Ath layer is completed.

[0025] According to the composite material grid structure forming method of the present invention, in the Z3 step, the number of nodes between two adjacent breakpoints on each layer of annular reinforcement is determined as follows:

[0026] According to the composite material grid structure forming method of the present invention, in the step Z6, the initial breakpoint of the first layer of ring ribs is used as a reference, and the initial breakpoint of each layer of ring ribs is determined in turn in a counterclockwise or clockwise manner.

[0027] According to the composite material grid structure forming method of the present invention, the breaking point is formed in such a way that the annular reinforcement is disconnected and arranged on both sides of the longitudinal reinforcement at the intersection of the annular reinforcement and the longitudinal reinforcement to form the breaking point.

[0028] According to the composite material grid structure forming method of the present invention, in the Z1 step, the process parameters also include fiber filament width L and fiber filament thickness t; the longitudinal reinforcement at the breakpoint position and the annular reinforcements on both sides form a gap with a distance t.

[0029] According to the composite material grid structure forming method of the present invention, in the Z6 step, when the calculation result of E / D is a non-integer, the number of compensation breakpoints in each cycle is calculated.

[0030] The compensation breakpoints are arranged on the last layer of ring reinforcement in each cycle; or the compensation breakpoints of each cycle are concentrated on the outermost layer of ring reinforcement.

[0031] According to the composite material grid structure forming method of the present invention, the number F of compensation breakpoints in each cycle does not exceed two.

[0032] According to the composite material grid structure forming method of the present invention, the number of layers of the longitudinal reinforcement and the annular reinforcement of the node is the same.

[0033] According to the composite material grid structure forming method of the present invention, the fiber bundles are prepregs.

[0034] In summary, the present invention optimizes the breakpoint distribution method so that the breakpoints of two adjacent layers do not overlap, thereby avoiding the breakpoints being concentrated in a certain layer and destroying the mechanical properties of the entire grid structure; at the same time, it also avoids the situation where the breakpoints are concentrated in the same node. The breakpoint distribution method of the present invention realizes the control of the total thickness of the node, while avoiding the concentrated distribution of the breakpoints, and optimizing the mechanical properties of the grid structure. Optimizing short-range laying and increasing the length of a single fiber bundle laying by multiples can reduce the production requirements for equipment and reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of the prior art;

[0036] Figure 2 yes Figure 1 The structural diagram of the middle A direction;

[0037] Figure 3 It is a schematic diagram of the structure of the present invention;

[0038] Figure 4 yes Figure 3 Schematic diagram of the cross-sectional structure of the intersection of the longitudinal reinforcement and the annular reinforcement in the middle B area;

[0039] Figure 5 yes Figure 3 Schematic diagram of the cross-sectional structure of the longitudinal reinforcement and the annular reinforcement at the breakpoint in the middle C area;

[0040] Figure 6 is a schematic diagram of a cross-sectional structure of a multi-layer node according to an embodiment of the present invention;

[0041] Figure 7 is a schematic diagram of a cross-sectional structure of a multi-layer node according to an embodiment of the present invention;

[0042] Figure 8 Schematic diagram of the breakpoint distribution structure of each embodiment 1 in Table 1 of the present invention;

[0043] Fig. 9 Schematic diagram of the breakpoint distribution structure of each embodiment 2 in Table 1 of the present invention;

[0044] Fig.10 Schematic diagram of the breakpoint distribution structure of each embodiment 3 in Table 1 of the present invention;

[0045] Fig.11 Schematic diagram of the breakpoint distribution structure of each embodiment 4 in Table 1 of the present invention;

[0046] Fig.12 Schematic diagram of the breakpoint distribution structure of each comparative example 1 in Table 2 of the present invention;

[0047] Fig.13 Schematic diagram of the breakpoint distribution structure of each comparative example 2 in Table 2 of the present invention;

[0048] Fig.14 Schematic diagram of the breakpoint distribution structure of each comparative example 3 in Table 2 of the present invention;

[0049] Fig.15 Schematic diagram of the breakpoint distribution structure of each comparative example 4 in Table 2 of the present invention;

[0050] Fig.16 is a side view of Example 1 in Table 1 of the present invention;

[0051] Fig.17 is a side view of Example 2 in Table 1 of the present invention;

[0052] In the figure: 1-longitudinal reinforcement, 2-annular reinforcement, 3-breakpoint, 100-mold, 200-wire laying equipment. DETAILED DESCRIPTION

[0053] See also Figure 3 The present invention provides a composite material grid structure forming method, comprising the following steps:

[0054] S1, using fiber bundles, laying multiple longitudinal ribs 1 along the axial direction on the outer surface of the cylindrical mold 100, and each longitudinal rib 1 is evenly arranged around the central axis of the mold 100;

[0055] S2, using fiber bundles, laying multiple annular ribs 2 in sequence and at intervals along the axial direction of the cylindrical mold 100; each annular rib 2 is arranged circumferentially around the mold 100 and intersects with each longitudinal rib 1 in sequence;

[0056] Combination Figure 4 At the intersection of the annular reinforcement 2 and the longitudinal reinforcement 1, the annular reinforcement 2 can be bypassed from the outside to keep the continuity of the annular reinforcement 2. Correspondingly, the thickness of the node is increased.

[0057] Optionally, the fiber bundle is a prepreg.

[0058] S3, repeating steps S1 and S2 until a predetermined number of laying layers is reached, forming the grid structure; the grid structure has a plurality of longitudinal ribs and annular ribs; the intersection of the longitudinal ribs and the annular ribs forms a node; see Figure 6 and Figure 7 , each node includes multiple layers of cross-stacked longitudinal reinforcement 1 and annular reinforcement 2; the number of layers of annular reinforcement 2 in the annular reinforcement channel is denoted as A;

[0059] Optionally, the number of layers of longitudinal reinforcement 1 and annular reinforcement 2 at each node is the same.

[0060] During the laying process of each layer of ring reinforcement 2 of each ring reinforcement channel, breakpoints are formed on each layer of ring reinforcement 2 from the inside to the outside in accordance with the predetermined breakpoint layout method; the breakpoints on any layer of ring reinforcement 2 of each ring reinforcement channel are staggered with the breakpoints of the adjacent layer of ring reinforcement 2 to avoid the breakpoints being concentrated in a certain layer, which would damage the mechanical properties of the entire grid structure; at the same time, the breakpoints of two adjacent layers do not overlap, which also avoids the situation where the breakpoints are concentrated in the same node. The breakpoint distribution method of the present invention realizes the control of the total thickness of the node, while avoiding the concentrated distribution of the breakpoints, and optimizing the mechanical properties of the grid structure.

[0061] See also Figure 5 The structure of the breakpoint is as follows: at the intersection of the annular reinforcement 2 and the longitudinal reinforcement 1, the annular reinforcement 2 is broken and arranged on both sides of the longitudinal reinforcement 1 to form the breakpoint; the thickness at the breakpoint position is the same as the thickness of a single layer of the annular reinforcement 2 or the longitudinal reinforcement 1, thereby reducing the thickness of the joint.

[0062] Optionally, the longitudinal reinforcement 1 and the annular reinforcement 2 of the present invention are pressed onto the outer surface of the mold 100 by the wire laying equipment 200 .

[0063] As an embodiment, in the step S3, the breakpoint arrangement method of each ring rib includes the following steps:

[0064] Z1, determine the process parameters;

[0065] The process parameters include the continuous ratio H of the fiber bundles, the number C of longitudinal reinforcements in step S1; the number A of ring reinforcement layers and the number E of nodes in each ring reinforcement in step S3;

[0066] A node is formed at the intersection of the longitudinal reinforcement 1 and the annular reinforcement 2. It can be seen that the number of nodes E = the number of longitudinal reinforcements C;

[0067] Optionally, those skilled in the art may determine the values ​​of the process parameters according to the design requirements of the grid structure.

[0068] Z2, determine the ring reinforcement continuity ratio B = [1-2*(1-H)]*100%;

[0069] Z3, determine the number of breakpoints per layer That is, the calculation result is rounded down to an integer;

[0070] Z4, determine the distribution of breakpoints on the first layer of annular reinforcement 2;

[0071] The distribution method of the breakpoints is: a node of the ring reinforcement 2 of this layer is selected as the initial breakpoint, and the remaining breakpoints are set in sequence with the same number of nodes;

[0072] Optionally, in step Z3, the number of nodes between two adjacent breakpoints on each layer of ring reinforcement 2 is determined as follows:

[0073] See Table 1. For example, if the node E is 36 and the number of breakpoints per layer is D is 9, then the number of nodes between two adjacent breakpoints is:

[0074] Similarly, when the number of nodes E = 36 and the number of breakpoints per layer D = 7, the number of nodes between two adjacent breakpoints is:

[0075] Combination Fig.16 and Fig.17 The breakpoints on each layer of the annular ribs 2 of the present invention are distributed in a uniform or quasi-uniform manner, which disperses the distribution of the breakpoints and avoids the concentration of the breakpoints, which causes stress concentration and deteriorates the mechanical properties of the annular ribs 2 of this layer.

[0076] Z5, determine the distribution of breakpoints on the next layer of ring reinforcement 2;

[0077] The distribution of the breakpoints on the ring reinforcement 2 of this layer is as follows: the initial breakpoint of this layer is offset by one node from the initial breakpoint of the previous layer; the remaining breakpoints are set in the manner of step Z4;

[0078] In this way, the breakpoints of two adjacent layers can be staggered to avoid overlapping breakpoints in the same joint, thus optimizing the breakpoint distribution.

[0079] Z6, repeat step Z5 until a cycle of ring reinforcement 2 is laid; the number of layers of ring reinforcement 2 in each cycle is

[0080] See Table 1, for example, node E = 36, the number of breakpoints per layer D = 9; then the number of layers of ring reinforcement 2 in each cycle is That is, each cycle includes 4 layers of annular reinforcement 2, and the phase of the initial breakpoint of the fifth layer of annular reinforcement 2 is the same as the phase of the initial breakpoint of the first layer, that is, the second cycle of laying is started from the fifth layer.

[0081] For example, if node E = 36 and the number of breakpoints per layer D = 7, then the number of layers of ring reinforcement 2 in each cycle is That is, each cycle includes 5 layers of annular reinforcement 2, and the phase of the initial breakpoint of the sixth layer of annular reinforcement 2 is the same as the phase of the initial breakpoint of the first layer, that is, the second cycle of laying starts from the sixth layer.

[0082] Optionally, in step Z6 of the present invention, the initial breakpoints of the first layer of annular ribs 2 are used as a reference, and the initial breakpoints of the annular ribs 2 of each layer are determined in turn in a counterclockwise or clockwise manner to ensure that the breakpoints of two adjacent layers are staggered.

[0083] Z7, according to the number of ring reinforcement 2 layers A of the ring reinforcement, determine the number of cycles of step Z6 When the calculation result of A / G is not an integer, the Z5 step is repeated in the last cycle until the laying of the ring reinforcement 2 of the Ath layer is completed;

[0084] Even if the last cycle of the present invention cannot be completely executed, the breakpoints on the annular reinforcements 2 of two adjacent layers still do not overlap.

[0085] As an embodiment, when the continuous ratio H of the fiber bundle of the present invention and the continuous ratio B of the ring reinforcement are selected, the value of the number of longitudinal reinforcements C can be combined to make an adaptive approximation so that each period The E / D in the equation is divisible. The distribution of breakpoints in the grid structure is optimized.

[0086] As an implementation mode, in the step Z6, when the calculation result of E / D is a non-integer, the number of compensation breakpoints in each cycle is calculated.

[0087] The compensation breakpoints can be arranged on the last layer of annular ribs 2 in each cycle, or the number of compensation breakpoints in each cycle can be set together and arranged on the outermost layer of annular ribs 2 of the annular ribs. Those skilled in the art can make adaptive approximations based on the actual design requirements of the grid structure so that the number of compensation breakpoints F in each cycle does not exceed two.

[0088] The present invention can reduce the number of compensation breakpoints, only affecting the uniformity of the distribution of breakpoints on a few layers of annular reinforcements, and has no effect on the overall mechanical properties of the grid structure.

[0089] As an embodiment, in step Z1 of the present invention, the process parameters further include fiber filament width L and fiber filament thickness t;

[0090] contrast Figure 6 and Figure 7 At the breakpoint, the longitudinal reinforcement 1 and the annular reinforcements 2 on both sides form a gap with a distance t; the thickness at the breakpoint is further reduced to weaken the stress concentration.

[0091] As an implementation method, when the breakpoint is formed, the annular reinforcement 2 is laid on one side of the longitudinal reinforcement 1 and stops when the distance from the longitudinal reinforcement 1 is t; then the mold 100 rotates a distance of L+2t, and then the annular reinforcement 2 on the other side is laid to form the breakpoint.

[0092] The present invention sets multiple embodiments, and the specific parameters are shown in Table 1. The breakpoint distribution mode of each layer in each cycle of each embodiment is shown in Table 1. Figure 8-11 To clearly show the structural features, Figure 8-11 There is a gap between the longitudinal reinforcement layer and the annular reinforcement layer in each embodiment. In the actual structure, at the non-node position, each layer of longitudinal reinforcement 1 and each layer of annular reinforcement 2 are stacked in sequence.

[0093] At the same time, the present invention also sets a pair of comparisons for each embodiment. The fiber bundle continuity ratio H, the ring reinforcement continuity ratio B, the number of nodes C, the total number of ring reinforcement layers A and the total number of breakpoints of each comparison example are the same as those of the corresponding embodiment. The difference is that the breakpoint distribution method of the comparison example adopts the existing technology. For specific parameters, see Table 2, and the breakpoint structure of each comparison example see Figure 12-15 For comparison with the embodiment, Figure 12-15 Only the number of layers per cycle of each comparative example is listed.

[0094] It should be noted that the prior art sets all nodes of a certain layer of ring reinforcement 2 as breakpoints, so the ring reinforcement 2 layer is a breakpoint layer. The total number of breakpoints / number of nodes C is rounded up to determine the number of breakpoint layers for each comparison ratio, which is the number of breakpoint layers in Table 2.

[0095] Similarly, the total number of annular reinforcement layers A / the number of breakpoint layers can determine the number of annular reinforcement layers required for a breakpoint layer, that is, the number of breakpoint layer periodic layers. Note that for the convenience of comparison with the embodiment, the number of breakpoint layer periodic layers of comparative example 1 is rounded up to 4 layers.

[0096] Comparing the corresponding embodiments and comparative examples, the total thickness of each node in each embodiment of the present invention is the same as that of the comparative example using the prior art to set the breakpoint. Fig.16 and Fig.17 , but the breakpoints of each layer are evenly distributed, and the breakpoints are not concentrated in a certain layer, and the breakpoints of two adjacent layers do not overlap. Under the premise of controlling the total thickness of the node, the breakpoints are highly dispersed to avoid stress concentration, eliminate weak points, and improve the overall mechanical properties of the grid structure.

[0097] Table 1: Parameters of various embodiments

[0098]

[0099] Table 2: Parameters of each comparative example

[0100]

[0101]

[0102] In summary, the present invention provides a composite material grid structure forming method, which optimizes the breakpoint distribution mode so that the breakpoints of two adjacent layers do not overlap, avoids the breakpoints being concentrated in a certain layer, and destroys the mechanical properties of the entire grid structure; at the same time, it also avoids the situation where the breakpoints are concentrated in the same node. The breakpoint distribution mode of the present invention realizes the control of the total thickness of the node, while avoiding the concentrated distribution of the breakpoints, and optimizes the mechanical properties of the grid structure.

[0103] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A composite material grid structure forming method, characterized in that: The steps include: S1, using fiber bundles, laying multiple longitudinal ribs along the axial direction on the outer surface of the cylindrical mold, and each longitudinal rib is evenly arranged around the central axis of the mold; S2, using fiber bundles, laying multiple annular ribs in sequence and at intervals along the axial direction of the cylindrical mold; each annular rib is arranged around the circumference of the mold and intersects with each longitudinal rib in sequence; S3, repeating steps S1 and S2 until a predetermined number of laying layers is reached to form the grid structure; The grid structure has a plurality of longitudinal reinforcements and annular reinforcements; the intersections of the longitudinal reinforcements and the annular reinforcements form nodes; each node includes multiple layers of cross-stacked longitudinal reinforcements and annular reinforcements; the number of annular reinforcement layers of the annular reinforcement is denoted as A; During the laying process of each layer of ring reinforcement of each ring reinforcement channel, breakpoints are formed on each layer of ring reinforcement from the inside to the outside in accordance with a predetermined breakpoint layout; the breakpoints on any layer of ring reinforcement of each ring reinforcement channel are staggered with the breakpoints of the adjacent layer of ring reinforcement.

2. The composite material grid structure forming method according to claim 1, characterized in that: In the step S3, the breakpoint arrangement method of each ring reinforcement includes the following steps: Z1, determine the process parameters; The process parameters include the continuous ratio H of the fiber bundles, the number C of longitudinal reinforcements in step S1; the number A of ring reinforcement layers and the number E of nodes in each ring reinforcement in step S3; the number E of nodes = the number C of longitudinal reinforcements; Z2, determine the ring reinforcement continuity ratio B = [1-2*(1-H)]*100%; Z3, determine the number of breakpoints per layer That is, the calculation result is rounded down to an integer; Z4, determine the distribution of breakpoints on the first layer of ring reinforcement; The distribution method of the breakpoints is: select a node of the ring reinforcement layer as the initial breakpoint, and set the remaining breakpoints in sequence with the same number of nodes; Z5, determine the distribution of breakpoints on the next layer of ring reinforcement; The distribution of the breakpoints on the ring reinforcement of this layer is as follows: the initial breakpoint of this layer is offset by one node from the initial breakpoint of the previous layer; the remaining breakpoints are set in the same manner as in step Z4; Z6, repeat step Z5 until a cycle of ring reinforcement laying is completed; the number of layers of ring reinforcement in each cycle is Z7, according to the number of ring reinforcement layers A, determine the number of cycles of step Z6 When the calculation result of A / G is not an integer, step Z5 is repeated in the last cycle until the laying of the ring reinforcement of the Ath layer is completed.

3. The composite material grid structure forming method according to claim 2, characterized in that: In the Z3 step, the number of nodes between two adjacent breakpoints on each layer of ring reinforcement is determined as follows:

4. The composite material grid structure forming method according to claim 2, characterized in that: In the step Z6, the initial breakpoints of the first layer of annular reinforcement are used as a reference, and the initial breakpoints of the annular reinforcements of each layer are determined in turn in a counterclockwise or clockwise manner.

5. The composite material grid structure forming method according to claim 1, characterized in that: The breaking point is formed in the following manner: at the intersection of the annular reinforcement and the longitudinal reinforcement, the annular reinforcement is disconnected and arranged on both sides of the longitudinal reinforcement to form the breaking point.

6. The composite material grid structure forming method according to claim 5, characterized in that: In the Z1 step, the process parameters also include the fiber filament width L and the fiber filament thickness t; the longitudinal ribs at the breakpoint position and the annular ribs on both sides form a gap with a distance t.

7. The composite material grid structure forming method according to any one of claims 2 to 6, characterized in that: In step Z6, when the calculation result of E / D is non-integer, the number of compensation breakpoints in each cycle is calculated. The compensation breakpoints are arranged on the last layer of ring reinforcement in each cycle; or the compensation breakpoints of each cycle are concentrated on the outermost layer of ring reinforcement.

8. The composite material grid structure forming method according to claim 7, characterized in that: The number F of compensation breakpoints per cycle does not exceed two.

9. The composite material grid structure forming method according to claim 7, characterized in that: The number of layers of longitudinal reinforcement and annular reinforcement of the node is the same.

10. The composite material grid structure forming method according to claim 7, characterized in that: The fiber bundle is a prepreg.

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