Composite material stringer blanking drawing generation method considering prepreg thickness

Abstract

The invention relates to a method for generating a blanking drawing of a composite stringer, and belongs to the technical field of manufacturing of composite parts. A composite material stringer blanking drawing generation method considering the prepreg thickness comprises the following steps that (1) a die attaching face of laying layer design is expanded, and a quantity releasing area is additionally arranged on each of the two sides of a theoretical contour area of a part to form a new expanded die attaching face; (2) creating boundary lines on the two sides of a ladder layer in the quantity amplification area; (3) carrying out layering design in the composite material design software to generate a ladder layer; (4) exporting a blanking drawing of the laying layer; (5) typesetting the exported blanking drawing by using typesetting software; and (6) cutting the material sheets by using an automatic blanking machine according to the typeset blanking drawing. The method has the following advantages: a digital precise manufacturing concept is really realized; the working efficiency is greatly improved; the material utilization rate can be effectively improved, and cost is reduced.

Description

Technical Field

[0001] The present invention relates to a method for generating a cutting plan for a composite stringer, belonging to the technical field of composite part manufacturing. Background Art

[0002] With the rapid development of computer technology and numerical control technology, composite material manufacturing technology has advanced towards full digitization. By integrating the external shape information and manufacturing information of parts, etc., the parallel design and manufacturing of parts and materials are realized in digital form. Applying digital technology to the entire manufacturing process of composite parts is one of the main ways to achieve precise manufacturing. Thus, advanced modes of digital quantity transfer and automated production have emerged in composite material manufacturing. The automatic cutting system for composite material layup is a typical example, so the accuracy of the cutting plan as the input of the cutting system is very important.

[0003] For a "T"-shaped composite stringer that does not require allowance, when laying an "L"-shaped prepreg on the mandrel (see Figure 1 ), considering the influence of material thickness, the cutting plan dimensions for laying from bottom to top should gradually increase in the width direction. Currently, there are mainly two methods for generating the cutting plan: The first is to perform layup design in the composite material design software according to the theoretical boundary of the part, and then use the offset function of the software to solve the influence of the prepreg thickness on the cutting plan to generate the cutting plan; the second is to first use the composite material design software to generate the cutting plan, and then enlarge it in the AutoCAD software to solve the influence of the prepreg thickness on the cutting plan. However, in the co-bonding forming process of post-curing of the stringer, for stringers laid without allowance, there are the following problems and deficiencies: 1) The generated cutting plan has a large deviation and insufficient increment in the width direction Practice has proved that for stringers that do not require allowance, the dimensions of the cutting plan generated by the traditional first method can meet the requirements in the length direction, but in the width direction, the increment of the cutting plan dimensions for laying from bottom to top is insufficient. After laying the "L"-shaped prepreg on the mandrel, the two ends of the cross-section of the blank present a slope shape (see Figures 2-3 ), which cannot meet the manufacturing process requirements.

[0004] 2) The efficiency of generating the cutting plan is low The traditional method of enlarging the cutting plan in the AutoCAD software can solve the problem of insufficient increment in the width direction of the cutting plan for laying from bottom to top, but because it is an overall enlargement, it will cause the cutting plan to expand in the length direction, increasing the workload of workers to cut the excess edge material after laying. In addition, in the AutoCAD software, the cutting plan of each layup needs to be modified. When there are many layups, the workload is large and the efficiency is low. Summary of the Invention

[0005] The object of the present invention is to provide a fast, simple and efficient method for generating a cutting layout diagram of a composite stringer considering the prepreg thickness, so as to promote the digital precise manufacturing of "T"-shaped composite stringer parts.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A method for generating a cutting layout diagram of a composite stringer considering the prepreg thickness, comprising the following steps: Enlarge the mold-fitting surface of the ply design, add a margin area on both sides of the theoretical contour area of the part to form a new extended mold-fitting surface; Create the two side boundary lines of the ladder layer in the margin area; (3) Perform ply design in the composite material design software to generate a ladder layer; (4) Export the cutting layout diagram of the ply; (5) Use typesetting software to typeset the exported cutting layout diagram; (6) According to the typeset cutting layout diagram, use an automatic cutting machine to cut the material sheet.

[0007] Preferably, in step (1), enter the surface design module of CATIA software, extract the "L"-shaped surface of the "T"-shaped stringer as the theoretical mold-fitting surface, extract the entire boundary of the mold-fitting surface as the obtained theoretical contour of the part, and use it as the boundary of the first ply.

[0008] Preferably, in step (1), extrapolate and extend the four sides of the theoretical mold-fitting surface in parallel, the extrapolation and extension area is the margin area, combine the theoretical mold-fitting surface and the margin area to obtain the extended mold-fitting surface of the ply design, and extract the entire boundary of the extended mold-fitting surface as the boundary of the last ply.

[0009] Preferably, in step (2), call the "parallel curve" command to make parallel lines of the two side edges of the theoretical contour of the part in the margin area as the side boundary lines of the middle ladder layer.

[0010] Preferably, in step (3), in the composite material design software, use the CEE module to perform ply design.

[0011] Preferably, in step (3), generating the ladder layer includes the following steps: 1) Define the laying surface of the Laminate as the extended film-laying surface; 2) Define the zero-degree direction of the ply coordinate system; 3) Define the boundaries of the first ply and the last ply; 4) Define the boundaries of the middle ladder layer; 5) Generate the ladder layer.

[0012] Preferably, in step (2), the two side boundaries of the middle ladder layer are within the margin area.

[0013] Preferably, in step (4), within the composite material design software, perform manufacturability analysis on the generated ladder layer, then generate the cutting layout diagram of the ply, and use the output interface to export the cutting layout diagram of the ply. The width of the ply increases layer by layer from bottom to top, and the length remains unchanged.

[0014] Preferably, adopt the co-bonding forming process with post-curing of stringers, and the stringers need to be laid with net dimensions.

[0015] Preferably, use FiberSIM as the composite material design software; use CutWorks as the layout software.

[0016] Compared with the prior art, the present invention has the following advantages: 1) This method can generate a relatively accurate cutting layout diagram, which can be directly used in production after layout and ply cutting. For the composite material stringers laid without leaving allowances, it truly realizes the concept of digital precision manufacturing. 2) The cutting layout diagram generated by this method does not need to be modified by the process engineer, does not require manual cutting of the ply, and does not require workers to cut the excess edge material after laying, greatly improving the work efficiency. 3) Layout the generated accurate cutting layout diagram, which can effectively improve the material utilization rate and reduce the cost. Description of the Drawings

[0017] Figure 1 is a schematic cross-sectional view of the "T" - shaped stringer ply in the background art of the present invention; Figure 2 is a schematic cross-sectional view of laying in the background art of the present invention; Figure 3 Schematic diagram of the cutting layout diagram generated in the background art of the present invention; Figure 4 is a schematic cross-sectional view of laying in the embodiment of the present invention; Figure 5 is a schematic diagram of the area of the die surface for laying design in the embodiment of the present invention; Figure 6 is a schematic diagram of the generated ply in the ply design of the embodiment of the present invention; Figure 7 is a schematic diagram of the cutting layout diagram generated in the embodiment of the present invention; Figures 1-3 In, 1, core mold; 2, "L" - shaped ply group; 3, prepreg thickness; 4, die surface; 5, end shape; Figures 4-7 In, 1, core mold; 2, "L" - shaped ply group; 4, die surface; 5, end shape; 6, allowance area; 7, theoretical contour of the part; 8, ladder layer boundary. Detailed Embodiments

[0018] It should be noted that terms such as "upper" and "lower" are described in accordance with the figures shown and do not constitute a limitation to the present invention. Those of ordinary skill in the art should understand in line with the technical solution of the present invention.

[0019] The following further details the present invention with reference to the Figures 4-7 For the "T"-shaped composite stringer without allowance laying under the co-bonding forming process with post-curing of the stringer, in the surface design module of CATIA software, on both sides of the area of the theoretical contour 7 of the part outside the mold-fitting surface 4, add a margin area 6 on each side, and combine the mold-fitting surface and the margin areas on both sides to obtain the extended mold-fitting surface for ply design, as Figure 5 shown. On the margin areas on both sides, call the "parallel curve" command to make parallel lines of the two sides of the theoretical contour 7 of the part, and obtain the two side boundary lines of the middle ladder layer. In the composite material design software, lay the plies according to the ladder layer design. The first ply is the theoretical size, the boundary is the theoretical contour of the part, and the width dimension of the ply increases gradually from bottom to top to consider the influence of the prepreg thickness. The boundary of the last ply is the entire boundary of the extended mold-fitting surface. Then, directly output the cutting pattern of all plies at one time using the software, and cut the material pieces using an automatic cutting machine after typesetting. According to the ply laying sequence, lay the material pieces on the core mold 1 to generate the "L"-shaped ply group 2 and the end shape 5 of the net-size "T"-shaped composite stringer.

[0020] Specifically, a method for generating a cutting pattern of a composite stringer considering the prepreg thickness includes the following steps: 1) Enter the surface design module of CATIA software, extract the "L"-shaped surface of the "T"-shaped stringer as the theoretical mold-fitting surface 4, and extract the entire boundary of the mold-fitting surface as the theoretical contour 7 of the part. Parallelly extrapolate and extend the four sides of the theoretical mold-fitting surface. Add a margin area 6 on each side outside the mold-fitting surface 4, combine the mold-fitting surface and the margin areas on both sides to obtain the extended mold-fitting surface for ply design, and extract the entire boundary. On the margin areas on both sides of the extended mold-fitting surface, call the "parallel curve" command to make parallel lines of the two sides of the theoretical contour 7 of the part, and obtain the two side boundary lines of the middle ladder layer. 2) In the composite material design software FiberSIM, use the CEE module for ply design. Define the extended mold-fitting surface as the laying surface of the Laminate; design the Rosette according to the zero-degree direction of the ply; create ply. The boundary of the first ply is the theoretical contour 7 of the part, and the boundary of the last ply is the entire boundary of the extended mold-fitting surface. The parallel lines of the two sides of the theoretical contour 7 of the part are sequentially set as the boundaries of the middle plies. The width dimension of the ply increases gradually from bottom to top, and the length remains unchanged. The ladder layer boundary 8 is within the margin area, as shown in the Figure 6 figure; 3) Within the FiberSIM software, perform manufacturability analysis on the generated ply, and then generate a two-dimensional development drawing (nesting drawing) of the ply. Use the output interface Flat Pattern Export to export the nesting drawing of the ply. The width of the ply increases layer by layer from bottom to top, while the length remains unchanged to consider the influence of the prepreg thickness on the nesting drawing, as shown in the appendix Figure 7 as shown; 4) Open the exported nesting drawing with the CutWorks layout software, set the ply spacing, length, and width of the prepreg, and layout the nesting drawing to improve the material utilization rate; 5) Cut the ply according to the layout nesting drawing using an automatic cutting machine; 6) According to the ply sequence, lay the ply on the core mold 1 to generate the "L"-type ply group 2 and the end shape 5 of the net-sized "T"-shaped composite stringer.

[0021] The above embodiments are only preferred embodiments of the present invention and do not constitute a limitation to the present invention. Any extension, deformation, etc. made by those of ordinary skill in the art without departing from the principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for generating a cutting diagram of a composite material long stringer taking into account the thickness of prepreg, characterized in that: The following steps are involved: (1) Expand the die surface of the laminate design and add a bulking area on both sides of the theoretical contour area of ​​the part to form a new extended die surface; (2) Create boundary lines on both sides of the ladder layer in the volume expansion area; (3) Perform layer design in the composite design software to generate ladder layers; (4) Export the cutting plan of the ply; (5) Use typesetting software to typeset the exported cutting drawing; (6) Use an automatic cutting machine to cut the material according to the cut-out drawing after typeset.

2. The method for generating a composite material long stringer blanking diagram considering the thickness of prepreg according to claim 1, characterized in that: In step (1), enter the surface design module of CATIA software, extract the "L"-shaped surface of the "T"-shaped long stringer as the theoretical die-mounting surface, extract the entire boundary of the die-mounting surface, and obtain the theoretical contour of the part as the boundary of the first layer.

3. The method for generating a composite material long stringer blanking diagram considering the thickness of prepreg according to claim 1 or 2, characterized in that: In step (1), the two sides of the theoretical die-stack surface are extended by parallel extrapolation. The extrapolated extension area is the bulk area. The extended die-stack surface of the layer design is obtained by combining the theoretical die-stack surface and the bulk area. The entire boundary of the extended die-stack surface is extracted as the boundary of the final layer. On the extended die-stack surface, the "parallel curve" command is called to make parallel lines on both sides of the theoretical contour of the part in the bulk area as the side boundary lines of the middle ladder layer.

4. The method for generating a composite material long stringer blanking diagram considering the thickness of prepreg according to claim 1, characterized in that: In step (2), the CEE module is used in the composite design software to perform layer layup design.

5. The method for generating a composite material long stringer blanking diagram considering the thickness of prepreg according to claim 1, characterized in that: In step (2), generating the ladder layer includes the following steps: 1) Define the extended film surface as the paving surface of Laminate; 2) Define the zero degree direction of the ply coordinate system; 3) Define the boundaries of the first and last layers; 4) Define the boundaries of the middle terrace; 5) Generate ladder layers.

6. The method for generating a composite material long stringer blanking diagram considering the thickness of prepreg according to claim 1, characterized in that: In step (4), a manufacturability analysis is performed on the generated ladder layer in the composite design software, and then a layup cutting plan is generated. The layup cutting plan is exported using the output interface. The width of the material sheet increases layer by layer from bottom to top, while the length remains unchanged.

7. The method for generating a composite material long stringer blanking diagram considering the thickness of prepreg according to claim 1, characterized in that: The co-bonding molding process with post-curing of the long stringers is adopted, and the long stringers need to be laid with clear dimensions.

8. The method for generating a composite material long stringer cutting diagram considering the thickness of prepreg according to claim 1, characterized in that: The composite design software used is FiberSIM; the typesetting software used is CutWorks.

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