A method for delaminating a polyhedral structure fiber reinforced composite article

Abstract

The application discloses a layered unfolding method of a polyhedral structure fiber reinforced composite part, and the method is characterized in that: the intersection point is determined to identify the material distribution line passing point and the cutting point, and then the material distribution scheme and the cutting scheme are designed in combination with the stress distribution direction in the part and the material direction benchmark, so that the problems in the prior art, such as the mismatch between the material type and the splicing line, the insufficient width, the unreasonable intersection point screening and the unfeasible process, are solved, and the process feasibility and the part performance are improved.

Description

Technical Field

[0001] This invention relates to the field of fiber-reinforced composite material molding technology, and specifically to a method for layering and unfolding polyhedral fiber-reinforced composite material parts. Background Technology

[0002] Fiber-reinforced composite materials possess advantages such as lightweight, high strength, high modulus, fatigue resistance, corrosion resistance, good designability, and processability, thus finding wide application in aerospace, automotive manufacturing, shipbuilding, and wind power industries. In these fields, polyhedral structures are a typical form of fiber-reinforced composite parts. When molding this type of part, to ensure the operability of the layup process, the surface of the polyhedral structure is unfolded and divided into several two-dimensional sheet units according to its size and structural shape. These two-dimensional sheet units are then spliced ​​or overlapped to achieve the layup of the polyhedral structure. During the sheet division, it is crucial to ensure that the two-dimensional sheet units do not self-intersect to guarantee layup processability. In addition, the following factors must be considered: (1) The influence of the material separation line on the molding quality and mechanical properties of fiber-reinforced composite parts. Currently, the materials used to prepare fiber-reinforced composite parts are usually woven prepregs and unidirectional tape prepregs. If the splicing lines or overlap lines on the unidirectional tape prepregs are not along the fiber direction, a large number of load-bearing fibers will be cut, resulting in a 30-40% decrease in the strength of the fiber-reinforced composite parts. If the splicing lines or overlap lines on the woven prepregs are in a single direction, their multidirectional characteristics cannot be utilized, the risk of shear stress concentration is high, and interlaminar failure is easily triggered. These factors seriously restrict the process feasibility and performance of fiber-reinforced composite parts.

[0003] (2) Material width limitation. Currently, the width of unidirectional tape prepreg in the industry is usually 100-150cm, and that of fabric prepreg is 100-200cm. The existing unfolding method does not take the width as a constraint, which results in the unfolded material sheet width exceeding the material width, making it impossible to cut directly. It is necessary to repeatedly adjust the material distribution plan, resulting in a low success rate of material sheet cutting and low production efficiency.

[0004] (3) Material utilization rate. An unreasonable material distribution line will lead to an increase in the number of material units, an increase in the splicing or overlapping lines of single-layer material units, low material utilization rate, and stress concentration in concave corner areas.

[0005] Based on the above considerations, it is urgent to optimize the layering and unfolding method of polyhedral fiber-reinforced composite parts to improve processability and part performance. Summary of the Invention

[0006] In view of this, the present invention provides a layer-by-layer unfolding method for polyhedral fiber-reinforced composite material parts, which can accurately realize the layer-by-layer unfolding method for polyhedral fiber-reinforced composite material parts with different configurations, and achieve the best processability of sheet laying.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for layer-by-layer unfolding of a polyhedral fiber-reinforced composite material part includes the following steps: S1. Determine the layup parameters based on the load-bearing type of the polyhedral fiber-reinforced composite material part to be formed, including: sheet layup cycle period and spacing constraints; In this invention, the load-bearing type includes primary load-bearing, secondary load-bearing, and non-load-bearing; Primary load-bearing components refer to structural components that bear and transmit the main load, such as the frame, A, B, and C pillars of a car body, and other components such as the wing spars, fuselage frame, and landing gear of an aircraft; Secondary load-bearing components refer to structural components that do not bear the main load, but bear and transmit secondary loads, local loads, or specific functional loads, such as bumper brackets, rearview mirror brackets, and interior panel frames of a car, and landing gear doors, outer skins, and fairings of an aircraft; Non-load-bearing components refer to parts that do not participate in bearing loads, such as decorative parts on cars and aircraft; Spacing constraints include: the spacing between adjacent overlap lines and the overlap amount; the spacing between adjacent splice seams and the splice seam width; S2. From the same side of the face of the polyhedral fiber-reinforced composite material part, determine the intersection points and classify them into points that must pass through the parting line and shear points. The determination method is as follows: Based on multiple faces on the intersection point to be determined, take each pair of adjacent faces as a face combination, and find the common face of the face combination among the remaining faces. The angle formed by the intersection lines L1 and L2 of the face combination and the common face on the common face is denoted as θ. When the angle θ of all face combinations on the common face of the intersection point is less than or equal to 180°, the intersection point is determined to be a shear point. When there is any face combination on the intersection point with an angle θ greater than 180° on the common face of the intersection point, the intersection point is determined to be a point that must pass through the parting line. The intersection point refers to a natural vertex (such as the vertex of a square pyramid) on the part composed of three or more faces. S3. Set the material distribution plan and shearing plan: S31. Design a layer-by-layer material distribution scheme for the sheet material within the layup cycle, including: determining the direction of the material distribution line based on the stress distribution direction within the part and the material direction reference; designing one or more basic material distribution lines that pass through the necessary points of the material distribution line without disrupting the effective stress transfer of the part, so that the same layer of sheet material is divided into several independent sheet material units, which facilitates the sheet material layup of multi-faceted fiber-reinforced composite material parts; the direction of the material distribution line of any two layers of sheet material within the same layup cycle cannot coincide; the material direction reference in this invention is defined as follows: establish a material coordinate system, with the main load-bearing direction of the fiber prepreg defined as 0°, that is: the fiber direction of the unidirectional tape prepreg is 0°; the warp direction of the fabric prepreg is 0°, the weft direction is 90°, and the diagonal directions of the warp and weft yarns are +45° and -45°, respectively; S32. Design a shearing scheme, including: designing a shearing line extending from the shearing point to the boundary of the material unit for the shearing point located at a non-boundary position on each material unit.

[0008] In another implementation, the following steps are also included: S4. Two-dimensional verification of geometry and mechanics, specifically including: S41. Based on the material distribution scheme and shearing scheme of S3, each material unit is simulated and unfolded in two dimensions for geometric verification: whether the material unit meets the requirement of no self-intersection; whether the size of the material unit meets the material width; whether the number of material units in the same layer meets the requirement of being less than or equal to 1 / 2 of the total number of faces of the polyhedral composite material part; S42. Mechanical verification of the material splitting line area and shearing area using mechanical software must meet the following requirements: the stress in the splicing line area and shearing area of ​​the main load-bearing component is ≤ 70% of the material yield strength, and the stress in the splicing line area and shearing area of ​​the secondary load-bearing component is ≤ 90% of the material yield strength. If any of the above verifications fail, return to step S2 to re-determine the intersection point based on the actual situation, or return to step S3 to adjust and optimize the material distribution line.

[0009] In another embodiment, the sheet layup cycle in step S1 should meet the following requirements: when the polyhedral fiber-reinforced composite material part is the main load-bearing component, the sheet layup cycle should be at least 4 layers; when the polyhedral fiber-reinforced composite material part is a secondary load-bearing component or a non-load-bearing component, the sheet layup cycle should be at least 3 layers.

[0010] In another implementation, the spacing constraints in step S1 should meet the following requirements: when the polyhedral fiber-reinforced composite material part is a main load-bearing part or a secondary load-bearing part, the spacing between adjacent overlap lines on the material sheet is greater than or equal to 25 mm, and the overlap amount is greater than or equal to 10 mm; when the polyhedral fiber-reinforced composite material part is a non-load-bearing part, the spacing between adjacent splicing lines on the material sheet is greater than or equal to 15 mm, and the splice seam width is less than or equal to 1.5 mm.

[0011] In another embodiment, the design method of the dividing line in S31 includes: when the material sheet is a unidirectional tape prepreg, the dividing line is designed along the 0° direction of the unidirectional tape prepreg; when the material sheet is a fabric prepreg, the dividing line can be designed along any one or more of the 0°, 90°, +45°, and -45° directions of the fabric prepreg.

[0012] In another implementation, among all the material distribution lines: the number of material distribution lines in the 0° direction accounts for more than or equal to 50%, and the number of material distribution lines in the 90° direction accounts for less than or equal to 20%.

[0013] In another embodiment, the design method for the cut line in step S32 includes: controlling the cut length to 10-30mm; when the material sheet is a unidirectional tape prepreg, the angle between the cut direction and the 0° direction of the unidirectional tape prepreg should be ≥45°; when the material sheet is a fabric prepreg, the angle between the cut direction and the 0° direction of the fabric prepreg should be ≥30°; when designing the cut, difficulties in laying caused by excessively long cuts should be avoided. In this invention, the cut can be a straight line, and the cut length is the length of the straight line; it can also be a non-straight line, such as a broken line composed of two straight lines, in which case the cut length is the sum of the lengths of the two straight lines, i.e., the path length.

[0014] In another implementation, when the size of the sheet unit exceeds the width of the material in step S41, an auxiliary dividing line parallel to the basic dividing line needs to be added between the basic dividing lines; the distance between the newly added auxiliary dividing line and the adjacent basic dividing line needs to meet the following requirements: ≥25mm for main load-bearing components or secondary load-bearing components, and ≥15mm for non-load-bearing components.

[0015] In another embodiment, in step S3, when the polyhedral fiber-reinforced composite material part is an appearance part, when designing the material layer distribution scheme and the shearing scheme for the appearance surface, the material distribution line and the shearing should be set on the appearance feature edge line.

[0016] Compared with the prior art, the beneficial effects of the present invention are at least as follows: (1) Significantly improved process feasibility: By classifying the intersection points on the structure into the necessary points of the material distribution line and the cutting points, a basis is provided for the design of the material distribution scheme and the cutting scheme, which greatly improves the success rate of material cutting and the yield rate of product forming, thereby improving production efficiency; (2) Material sheet and stress optimization: The number of material sheet units is reduced by more than 40%, the utilization rate of prepreg is improved, and stress concentration in concave corner areas of the structure is avoided. (3) Improved component performance: In this invention, the material type is combined with the setting of differentiated material separation lines, which can make the strength retention rate of unidirectional belt components reach 95% and the shear stress of fabric components decrease by 25%. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a polyhedral carbon fiber reinforced composite material part (structural component) from Example 1; Figure 2 This is a schematic diagram of the layup cycle of the polyhedral carbon fiber reinforced composite material part (structural part) in Example 1; Figure 3 This is a schematic diagram of the intersection points between polyhedral carbon fiber reinforced composite materials (structural components) in Example 1; Figure 4 A schematic diagram of the material distribution and cutting scheme for the first layer of carbon fiber fabric prepreg; Figure 5 A schematic diagram of the material distribution and cutting scheme for the second layer of carbon fiber fabric prepreg; Figure 6 A schematic diagram of the material distribution and cutting scheme for the third layer of carbon fiber fabric prepreg; Figure 7 A schematic diagram of the material distribution and cutting scheme for the fourth layer of carbon fiber fabric prepreg; Figure 8 A schematic diagram of the material distribution and cutting scheme for the fifth layer of carbon fiber fabric prepreg; Figure 9 This is a schematic diagram of the layup cycle of the polyhedral carbon fiber reinforced composite material part (appearance part) in Example 2; Figure 10 This is a schematic diagram of the material distribution and cutting scheme of the carbon fiber fabric prepreg used as the outer layer in Example 2; Explanation of reference numerals in the attached figures: 1-Splitting line; 2-Cutting line; 01-Intersection point one; 02-Intersection point two; 03-Intersection point three; 04-Intersection point four; 05-Intersection point five; 06-Intersection point six; 07-Intersection point seven; 08-Intersection point eight; 09-Intersection point nine; 10-Intersection point ten; 11-Intersection point eleven; 12-Intersection point twelve; Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1

[0020] See appendix Figure 1 This is a polyhedral carbon fiber reinforced composite material component, a main load-bearing structural component with no appearance requirements. Its layered unfolding method includes the following steps: S1. Determine the ply parameters based on the load-bearing type (main load-bearing component) of the part to be formed, including: sheet ply cycle period and spacing constraints; for details, see Appendix. Figure 2 In this embodiment, the layering cycle is 5, that is, the material distribution scheme of layers P01-P05 is not repeated, and the material distribution scheme of layer P06 is reused from layer P01, and the cycle is repeated in sequence; the material units in the same layer are overlapped to ensure the mechanical properties of the part, the spacing between adjacent overlap lines is set to be greater than or equal to 25mm, and the overlap amount of adjacent material units is 12-25mm. S2. The intersection points on the workpiece are determined from the same side, categorized as either mandatory material passing points or shearing points. The determination method is as follows: Based on multiple faces at the intersection point to be determined, any two adjacent faces are taken as a face combination, and the common face of this face combination is found from the remaining faces. The angle formed by the intersection lines L1 and L2 of this face combination and the common face on the common face is denoted as θ. When the angle θ of all face combinations at the intersection point on its common face is less than or equal to 180°, the intersection point is determined as a shearing point. When any face combination at the intersection point has an angle θ greater than 180° on its common face, the intersection point is determined as a mandatory material passing point. The determination of all intersection points must be uniformly performed from the same side of the face. Specifically, in this embodiment: located in the attached... Figure 3Observing from the exposed side, there are 12 intersection points of the part, labeled 01 to 12 in the attached diagram. Based on this side, each intersection point is judged sequentially. Taking intersection point 05 as an example, the surfaces on this intersection point include surface A, surface B, and surface C. Surface A and surface B are taken as a surface combination. The common surface of this surface combination (intersecting with both surface A and surface B) is surface C. Surface A and surface B have intersection lines L1 and L2 with the common surface C, respectively. The intersection lines L1 and L2 form an angle (a supplementary angle on a non-virtual extension plane) on the common surface C, denoted as θ. It is determined that this angle θ is greater than 180°. Similarly, taking surface A and surface C as the combined surface, surface B is the... The common surface, the angle θ formed by the combination of the surfaces on the common surface B is less than or equal to 180°; taking surfaces B and C as the combined surfaces, and surface A as the common surface of the combined surfaces, the angle θ formed by the combination of the surfaces on the common surface A is less than or equal to 180°. In summary, intersection point 505 is determined to be a point that the material separation line must pass through; the other intersection points are determined in the same way, and we get: intersection point 707, intersection point 1010, and intersection point 1212 are also points that the material separation line must pass through; intersection point 101, intersection point 202, intersection point 303, intersection point 404, intersection point 606, intersection point 808, intersection point 909, and intersection point 1111 are cutting points; S3. Design of material distribution and shearing scheme: S31. Design a layer-by-layer material distribution scheme for the sheet material within the layup cycle, including: determining the direction of the material distribution line based on the stress distribution direction and material orientation reference of the part surface, and then designing one or more basic material distribution lines that must pass through the material distribution line without destroying the effective stress transfer of the part, so that the same layer of sheet material is divided into several independent sheet material units to facilitate the sheet material layup of polyhedral composite material parts; the direction of the material distribution line of any two layers of sheet material within the same layup cycle cannot coincide. S32. Design a shearing scheme for the shearing points located at non-boundary positions on each material unit, including: designing a shearing line extending from the shearing point to the boundary of the material unit so that the material unit can be unfolded in two dimensions and there is no self-intersection. In this embodiment, a material distribution scheme is implemented for P01-P05 sheets, specifically: (1) See Appendix Figure 4(a) shows the first layer of material in the layup cycle, which is carbon fiber prepreg. Its layup angle is 0°, meaning that the warp direction of the carbon fiber prepreg is the same as the load-bearing direction. Based on the stress distribution direction within the part and the material direction reference (the parting line on the prepreg can be set along any one or more directions of 0°, ±45°, and 90°), the direction of the parting line is determined. One or more parting lines are designed based on the distribution of the points the parting line must pass through (intersection point 505, intersection point 707, intersection point 10, intersection point 12). The optional parting scheme is along the load-bearing direction. Two dividing lines are designed along the force direction (which is also the 0° direction of the carbon fiber prepreg) to divide the layer of material into three material units, with an overlap of 15mm between adjacent material units. For the eight notch points located outside the material unit boundaries, notch lines are designed extending from these points to the material unit boundaries to allow the material units to be unfolded in two dimensions without self-intersection. The notch length is controlled between 10-30mm, and the angle between the notch direction and the 0° direction of the prepreg is ≥30°. Based on the above dividing and notch design, each material unit is unfolded in two dimensions using software to obtain the cutting diagram, see [link to diagram]. Figure 4 (b); (2) See Appendix Figure 5 (a) shows the second layer of material in the cycle, which is carbon fiber prepreg with a layup angle of 90°, i.e., the angle between the warp direction and the load-bearing direction of the carbon fiber prepreg is 90°. Based on the stress distribution direction within the part and the material direction reference (the parting line on the prepreg can be set along any or multiple directions of 0°, ±45°, and 90°), the direction of the parting line is determined. Combining the distribution of the points the parting line must pass through (intersection point 505, intersection point 707, intersection point 10, intersection point 12), one or more parting lines different from the parting scheme of the first layer are designed. An optional material distribution scheme is to design two dividing lines perpendicular to the load-bearing direction (along the 0° direction of the carbon fiber prepreg) to divide the layer into three material units, with an overlap of 15mm between adjacent material units; for the eight notch points located at non-material unit boundaries, design notch lines extending from the notch points to the material unit boundaries, so that the material units can be unfolded in two dimensions without self-intersection, the notch length is controlled between 10-30mm, and the angle between the notch direction and the 0° direction of the prepreg is ≥30°; according to the above material distribution and notch scheme, unfold each material unit in two dimensions using software to obtain the cutting diagram, see... Figure 5 (b); (3) See Appendix Figure 6(a) shows the third layer in the cycle, which is a carbon fiber prepreg with a layup angle of +45°, i.e., the angle between the warp direction and the load-bearing direction of the carbon fiber prepreg is +45°. Based on the stress distribution direction within the part and the material direction reference (the parting line on the prepreg can be along any or multiple directions of 0°, ±45°, and 90°), the direction of the parting line is determined. Considering the distribution of the points the parting line must pass through (intersection point 505, intersection point 707, intersection point 10, intersection point 12), one or more parting lines different from the parting schemes of the first and second layers are designed. One optional parting scheme is to design three parting lines at a +45° angle to the load-bearing direction (along the 0° direction of the carbon fiber prepreg) to divide this layer into four layers. Each material sheet unit has an overlap of 15mm between adjacent units. In the above material distribution scheme, since the distribution line passes through two cutting points, namely intersection point 2 (02) and intersection point 4 (04), there are only 6 cutting points located outside the boundaries of the material sheet units after distribution: intersection point 1 (01), intersection point 3 (03), intersection point 6 (06), intersection point 8 (08), intersection point 9 (09), and intersection point 11 (11). Cutting lines extending from these 6 cutting points to the boundaries of the material sheet units are designed to allow the material sheet units to be unfolded in two dimensions without self-intersection. The cutting length is controlled between 10-30mm, and the angle between the cutting direction and the 0° direction of the prepreg fabric is ≥30°. The material sheet units are then unfolded in two dimensions using software according to the above material distribution and cutting scheme to obtain the cutting diagram, see [link to diagram]. Figure 6 (b); (4) See Appendix Figure 7(a) shows the fourth layer in the cycle, which is a carbon fiber prepreg with a layup angle of -45°, i.e., the angle between the warp direction and the load-bearing direction of the carbon fiber prepreg is -45°. Based on the stress distribution direction within the part and the material direction reference (the parting line on the prepreg can be along any or multiple directions of 0°, ±45°, and 90°), the direction of the parting line is determined. Considering the distribution of the points the parting line must pass through (intersection point 505, intersection point 707, intersection point 10, intersection point 12), one or more parting lines different from the parting schemes of the first, second, and third layers are designed. One optional parting scheme is to design three parting lines at a -45° angle to the load-bearing direction (along the 0° direction of the carbon fiber prepreg) to divide this layer. There are four material sheet units, with an overlap of 15mm between adjacent material sheet units. In the above material distribution scheme, since the material distribution line passes through two cutting points, namely intersection point 1 (01) and intersection point 3 (03), there are 6 cutting points located at non-material sheet unit boundaries after material distribution. These are intersection point 2 (02), intersection point 4 (04), intersection point 6 (06), intersection point 8 (08), intersection point 9 (09), and intersection point 11 (11). Cutting lines extending from these 6 cutting points to the material sheet unit boundaries are designed to allow the material sheet units to be unfolded in two dimensions without self-intersection. The cutting length is controlled between 10-30mm, and the angle between the cutting direction and the 0° direction of the prepreg fabric is ≥30°. The material sheet units are then unfolded in two dimensions using software according to the above material distribution and cutting scheme to obtain the cutting diagram, see [link to diagram]. Figure 7 (b); (5) See Appendix Figure 8 (a) shows the fifth layer in the cycle, which is a carbon fiber prepreg with a layup angle of 0°, i.e., the angle between the warp direction and the load-bearing direction of the carbon fiber prepreg is 0°. Based on the in-plane stress direction and material direction reference (the parting line on the prepreg can be along any or multiple directions of 0°, ±45°, and 90°), the direction of the parting line is determined. Combining the distribution of the points the parting line must pass through (intersection point 505, intersection point 707, intersection point 10, intersection point 12), one or more parting lines different from the parting schemes of the first, second, third, and fourth layers are designed. An optional material distribution scheme involves designing two distribution lines roughly along the ±45° direction of the carbon fiber prepreg to divide the layer into three material units, with an overlap of 15mm between adjacent material units. For the eight notch points located outside the material unit boundaries, design notch lines extending from these points to the material unit boundaries to allow for two-dimensional unfolding of the material units without self-intersection. The notch length is controlled between 10-30mm, and the angle between the notch direction and the 0° direction of the prepreg is ≥30°. Following the above material distribution and notch design, each material unit is two-dimensionally unfolded using software to obtain the cutting diagram, see [link to diagram]. Figure 8 (b); (6) If the part has a sixth, seventh, ... layer of material sheets, the material distribution scheme and shearing scheme in the above cycle are adopted in sequence. For example, the material distribution scheme and shearing scheme of the sixth layer of material sheets are the same as those of the first layer of material sheets; the material distribution scheme and shearing scheme of the seventh layer of material sheets are the same as those of the second layer of material sheets; and so on. S4, dual-dimensional verification optimization; S41. Based on the material distribution scheme and shearing scheme of S3, each material unit is simulated and unfolded in two dimensions for geometric verification: whether the material unit meets the requirement of no self-intersection; whether the size of the material unit meets the material width; whether the number of material units in the same layer meets the requirement of being less than or equal to 1 / 2 of the total number of faces of the polyhedral fiber-reinforced composite material part; S42. Mechanical verification of the material splitting line area and shearing area using mechanical software: the stress in the material splitting line area and shearing area of ​​the main load-bearing component is ≤70% of the material yield strength, and the stress in the material splitting line area and shearing area of ​​the secondary load-bearing component is ≤90% of the material yield strength. If any discrepancies are found in the above verification, then depending on the discrepancy, either return to step S2 to re-determine the intersection point, or return to step S3 to adjust and optimize the material distribution line. Specifically: (1) If the material unit has self-intersection, return to step S2 to verify whether the intersection point determination is incorrect; (2) If the size of the sheet unit exceeds the width of the material, an auxiliary dividing line parallel to the basic dividing line shall be added between the basic dividing lines so that the size of the sheet unit is smaller than the width of the material; the distance between the newly added auxiliary dividing line and the adjacent basic dividing line shall meet the following requirements: the main load-bearing component ≥ 25 mm, and the secondary load-bearing component or non-load-bearing component ≥ 15 mm. (3) If the number of sheet units in the same layer is greater than 1 / 2 of the total number of surfaces of the part, then it is necessary to return to step S31, readjust the material distribution scheme, reduce the number of material distribution lines, and thus reduce the number of sheet units; (4) If the stress in the material distribution line area and the shearing area is greater than the standard, you can return to S2 to re-verify whether the intersection point determination is wrong, and readjust the material distribution plan and the shearing plan.

[0021] Example 2 Compared to Example 1, the difference in this example is that the part is an exterior part. Therefore: In step S1, adjacent sheet units in the layup parameters can be spliced, with a splice width of less than 1.5 mm and a spacing of more than 15 mm between adjacent splices; see the layup cycle diagram. Figure 9 ; In step S3, when designing the material distribution scheme and the shearing scheme, for the sheet material that serves as the outer surface, the material distribution line and the shearing line should be set on the surface feature edge. Therefore, as a feasible material distribution scheme, see [reference needed]. Figure 10(a) See the material cutting diagram. Figure 10 (b).

[0022] Example 3 Compared to Example 1, this embodiment differs in that the sheet material used in the cycle is prepreg made of unidirectional carbon fiber tape. Therefore: In step S3, when designing the material distribution line scheme and the shearing scheme, the material distribution line can only be along the 0° direction (i.e., fiber direction) of the unidirectional carbon fiber tape prepreg, and the angle between the shearing direction and the 0° direction of the unidirectional tape prepreg is greater than or equal to 45°.

[0023] The above description is merely a specific embodiment of the present invention, providing a detailed description of the invention. Parts not covered herein are conventional techniques. However, the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for layered development of a polyhedral fiber-reinforced composite material part, characterized in that, Includes the following steps: S1. Determine the layup parameters based on the load-bearing type of the part to be formed, including: sheet layup cycle and spacing constraints; S2. From the same side of the surface of the part, determine the intersection points and classify them as either points through which the parting line must pass or points where the parting line must pass. The determination method is as follows: Based on multiple surfaces at the intersection point to be determined, take each pair of adjacent surfaces as a surface combination, and find the common surface of the surface combination from the remaining surfaces. The angle formed by the intersection lines L1 and L2 of the surface combination and the common surface on the common surface is denoted as θ. When the angle θ of all surface combinations at the intersection point on their respective common surfaces is less than or equal to 180°, the intersection point is determined to be a point where the parting line must pass. When any surface combination at the intersection point has an angle θ greater than 180° on its common surface, the intersection point is determined to be a point through which the parting line must pass. S3. Set the material distribution plan and shearing plan: S31. Design a material distribution scheme for each layer of sheet within the layup cycle, including: determining the direction of the material distribution line based on the stress distribution direction and material direction reference of the part surface; designing one or more basic material distribution lines that pass through the necessary points of the material distribution line without disrupting the effective stress transfer of the part based on the distribution of the necessary points of the material distribution line; the material distribution lines of any two layers of sheet within the same layup cycle cannot coincide. S32. Design a shearing scheme, including: designing a shearing line extending from the shearing point to the boundary of the material unit at the shearing point located at a non-boundary position on each material unit.

2. The method for layering and unfolding a polyhedral fiber-reinforced composite material part according to claim 1, characterized in that, It also includes the following steps: S4, Two-Dimensional Validation Optimization: S41. Based on the material distribution scheme and shearing scheme of S3, each material unit is simulated and unfolded in two dimensions for geometric verification: whether the material unit meets the requirement of no self-intersection; whether the size of the material unit meets the material width; whether the number of material units in the same layer meets the requirement of being less than or equal to 1 / 2 of the total number of faces of the polyhedral fiber-reinforced composite material part; S42. Mechanical verification of the material splitting line area and shearing area using mechanical software: The stress in the material splitting line area and shearing area of ​​the main load-bearing component is ≤ 70% of the material yield strength; the stress in the material splitting line area and shearing area of ​​the secondary load-bearing component is ≤ 90% of the material yield strength. If any of the above verifications fail, then depending on the discrepancy, either return to step S2 to re-determine the intersection point, or return to step S3 to adjust and optimize the material distribution line.

3. The method for layering and unfolding a polyhedral fiber-reinforced composite material part according to claim 2, characterized in that, In step S1, the sheet layup cycle should meet the following requirements: when the part is a main load-bearing component, the sheet layup cycle should be at least 4 layers; when the part is a secondary load-bearing component or a non-load-bearing component, the sheet layup cycle should be at least 3 layers.

4. The method for layer-by-layer unfolding of a polyhedral fiber-reinforced composite material part according to claim 1, characterized in that, In step S1, the spacing constraints should meet the following requirements: when the part is a main load-bearing component or a secondary load-bearing component, the spacing between adjacent overlapping lines on the material sheet should be greater than or equal to 25 mm, and the overlap amount should be greater than or equal to 12 mm; when the part is a non-load-bearing component, the spacing between adjacent splicing lines on the material sheet should be greater than or equal to 15 mm, and the splicing seam width should be less than or equal to 1.5 mm.

5. The method for layered unfolding of a polyhedral fiber-reinforced composite material part according to claim 1, characterized in that, The design method of the dividing line in step S31 includes: when the material sheet is a unidirectional tape prepreg, the dividing line can only be drawn along the 0° direction of the unidirectional tape prepreg; when the material sheet is a fabric prepreg, the dividing line can be drawn along any or multiple directions of the fabric prepreg, such as 0°, +45°, -45°, and 90°.

6. The method for layering and unfolding a polyhedral fiber-reinforced composite material part according to claim 5, characterized in that, Of all the material distribution lines: the number of material distribution lines in the 0° direction accounts for more than or equal to 50%, and the number of material distribution lines in the 90° direction accounts for less than or equal to 20%.

7. The method for layered unfolding of a polyhedral fiber-reinforced composite material part according to claim 1, characterized in that, The design method for the cut line in step S32 includes: the cut length is controlled between 10-30mm; when the material is a unidirectional tape prepreg, the angle between the cut direction and the 0° direction of the unidirectional tape prepreg should be ≥45°; when the material is a fabric prepreg, the angle between the cut direction and the 0° direction of the fabric prepreg should be ≥30°.

8. The method for layering and unfolding a polyhedral fiber-reinforced composite material part according to claim 2, characterized in that, When the size of the sheet unit exceeds the width of the material in step S41, an auxiliary dividing line parallel to the basic dividing line needs to be added between the basic dividing lines; the distance between the newly added auxiliary dividing line and the adjacent basic dividing line must meet the following requirements: ≥25mm for main load-bearing components and ≥15mm for secondary load-bearing components or non-load-bearing components.

9. The method for layering and unfolding a polyhedral fiber-reinforced composite material part according to claim 1, characterized in that, In step S3, when the part is an appearance part, the parting line and the shear line of the material sheet that serves as the appearance surface should be set on the appearance feature edge line.

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