A 3D printing forming method of a continuous fiber reinforced composite wing structure

Abstract

A kind of 3D printing forming method of continuous fiber reinforced composite wing structure, first generate the three-dimensional model of wing structure, extract its aerodynamic profile;Then design the wing internal structure of multiple support point stress, as the forming basis of wing rib and spar;Then according to support point coordinates and wing aerodynamic profile, the path planning is carried out to wing internal structure, generates the 3D printing path of wing rib and spar;Then the theoretical weight of wing overall structure is calculated, if satisfying lightweight demand, then next structure forming is carried out;If not satisfied, then through re-determining structure design parameter, until satisfying lightweight demand;Then the forming of relevant structure is realized by 3D printing equipment, wing rib is connected with spar;Finally, the wing outer skin is formed on the basis of wing internal structure, thus the continuous fiber reinforced composite lightweight structure wing workpiece is obtained;The present application realizes the controllable design and rapid forming of super-lightweight, high specific performance, low-cost composite wing structure.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aerospace equipment and continuous fiber reinforced composite 3D printing cross technology, and particularly relates to a 3D printing forming method of a continuous fiber reinforced composite wing structure. BACKGROUND

[0002] As a key main load-bearing component of an aircraft, the material and structural characteristics of a wing have an important influence on the performance of the aircraft. In recent years, the development of advanced composite materials represented by carbon fibers has made a great contribution to the weight reduction of aviation equipment, and the parts used by the composite materials have gradually transitioned from secondary load-bearing components to main load-bearing components. In the wing structure, although composite materials have been applied in the outer skin, the internal structure forming is still mainly based on metal materials due to the limitations of composite material manufacturing technology.

[0003] The continuous fiber reinforced composite 3D printing technology is different from the traditional manufacturing technology. The technology widens and improves the design freedom and manufacturability of the continuous fiber reinforced composite structure by applying advanced composite materials and novel additive manufacturing processes, and provides a new way for the forming of the composite wing structure. The technology uses small tows as raw materials, breaks the constraints of traditional composite material molding and laying technology in the fiber orientation, realizes the multi-angle free arrangement of the fiber path, and makes the integrated forming of the complex structure in the wing possible, thereby greatly reducing the number of various fasteners and connection assembly work of the wing. However, due to the complexity of the wing structure and the manufacturing process constraints of the continuous fibers, the research and development technology of the continuous fiber reinforced composite wing structure is not perfect, and there is a lack of targeted 3D printing forming method.

[0004] At present, most of the forming methods of the wing structure still use conventional metal material structure configuration to design the composite structure, and the forming method of the wing structure facing the continuous fiber reinforced composite 3D printing technology is still a technical blank. Therefore, the reinforcing characteristics of the continuous fibers and the flexible manufacturing advantages of the 3D printing cannot be fully utilized and utilized in the forming of the composite wing structure. For the composite wing structure, especially the internal load-bearing structure, it is necessary to utilize the characteristics of the material and structure to realize the performance requirements of lightweight and high load-bearing. However, the traditional forming method does not consider the forming characteristics of the 3D printing technology, so the collaborative design of the material and structure cannot be realized, and there is a serious redundancy of the material that cannot be distributed in the effective position, which greatly increases the structure weight and manufacturing cost, and it is difficult to play the advantages of the continuous fiber reinforced composite material in lightweight and high specific performance, thereby limiting the further development of the advanced composite material aviation equipment. SUMMARY

[0005] In order to overcome the defects of the prior art, the purpose of the present application is to provide a 3D printing forming method of a continuous fiber reinforced composite wing structure, which utilizes the controllable forming advantage of 3D printing technology for continuous fiber reinforced composite structure, generates a lightweight wing structure according to the wing aerodynamic shape and load bearing performance requirements, so as to realize the controllable design and rapid forming of the ultralight, high specific performance and low cost composite wing structure.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is:

[0007] A 3D printing forming method of a continuous fiber reinforced composite wing structure, comprising the following steps:

[0008] 1) generating a three-dimensional model of the wing structure by airfoil design software or existing airfoil structure, and extracting the wing aerodynamic shape profile of the three-dimensional model as the basis for forming the wing internal structure and outer skin;

[0009] 2) designing the wing internal structure according to the wing aerodynamic shape profile obtained in step 1) and the load bearing performance requirements of the wing under working conditions; the wing internal structure is composed of wing ribs and spars prepared by continuous fiber reinforced composite 3D printing technology, the number of wing ribs and spars is m and n respectively, and the node corresponding to the support point is represented as n ij , i = 1, 2, 3, …, m; j = 1, 2, 3, …, n; the spatial coordinates of the support point n ij are (x k , y k , z k ), wherein z k = z w (x k , y k ) - δ, z w represents the z-axis coordinate of the wing aerodynamic shape profile at the support point position, and δ represents the thickness of the wing outer skin; the support point coordinate information is used for the forming design of the spars and the wing ribs, and the spars and the wing ribs are formed by using different 3D printing reference surfaces in the same spatial coordinate system;

[0010] 3) path planning for the wing internal structure according to the wing aerodynamic shape profile information obtained in step 1) and the support point coordinate information obtained in step 2), i.e. the wing internal structure design parameters, and generating the 3D printing path of the wing ribs and the spars based on the manufacturing process constraints;

[0011] 4) calculating the theoretical weight W in of the wing internal structure according to the total length L of the composite 3D printing path obtained in step 3) and the weight w l of the composite material filament per unit length, i.e. W in = L × w l; in addition, according to the wing area S and the composite material weight w s The theoretical weight W of the outer skin of the wing sk , that is, W sk =Sxw s , then the theoretical total weight of the wing structure is W=W in +W sk ; if the theoretical total weight of the wing structure meets the lightweight requirement, the next step of structure forming is performed; if the theoretical total weight of the wing structure does not meet the lightweight requirement, the structure design parameters are re-determined internally through step 2) to reduce the support point density p to shorten the printing path length L until the lightweight requirement of the wing structure is met;

[0012] 5) After the above steps, the 3D printing path of each wing rib and spar of the wing internal structure is obtained, the corresponding composite material feeding parameters and printing nozzle moving speed are input, and the related structure is formed through a 3D printing device; then, the wing ribs and spars are connected by using the composite material bonding method, and the bonding position is the support point position provided in step 2), so as to connect the wing internal structure into a whole;

[0013] 6) Form the outer skin of the wing on the basis of the wing internal structure, so as to obtain a continuous fiber reinforced composite lightweight structure wing workpiece.

[0014] In the step 2), the wing internal structure is designed by using a multi-support point stress design, the support point n ij is changed in the coordinates (x k ,y k ) in the wing plane, k=1, 2, 3, …, m x n-1, m x n, so as to realize the adjustment of the wing internal structure; in addition, according to the load distribution of the wing, the bearing point density p (x k ,y k ) of the corresponding plane area is changed, so as to realize the controllable design of the bearing performance under different requirements.

[0015] The step 3) is specifically: according to the manufacturing process constraint of the continuous fiber reinforced composite 3D printing, the turning radius r set and the scanning interval h set of the printing path are determined, so that r set ≥R, h set≤H, wherein R, H are the minimum fiber rotation radius and the maximum scanning interval allowed by 3D printing; based on the spatial coordinates of the support points and the manufacturing process constraints, a printing path corresponding to the lower wing rib of the forming reference surface is first generated, which is composed of a wing rib outer contour path based on the wing aerodynamic contour profile and a wing rib filling path based on the internal structure support point coordinates; then, based on the connection relationship between the wing rib and the spar, the same principle is used to plan the path of the spar, wherein the outer contour path and the filling path of the spar are planned according to the support point coordinate position of the internal structure of the wing obtained in step 2).

[0016] The step 6) is specifically: regulating the position of the internal structure support points of the wing to constrain the interval distance d of adjacent wing ribs in the printing direction of the outer skin r , so that d r ≤D, wherein D is the maximum interval distance allowed by 3D printing suspension forming; at this time, the first layer of the outer skin is directly printed on the internal structure of the wing relying on the characteristics of the wing rib support and continuous fiber uninterrupted forming, then the wing angle is turned over and fixed, and the opposite area on the other side of the outer skin is printed and formed; thereafter, the outer skin of the wing is printed layer by layer with variable angle, and finally the 3D printing forming of the continuous fiber reinforced composite wing structure is realized.

[0017] The beneficial effects of the present application are:

[0018] The present application proposes a 3D printing forming method for a continuous fiber reinforced composite wing structure, which realizes rapid forming of a super-lightweight, high-specific-performance wing structure by utilizing the characteristics of lightweight composite materials and 3D printing process. The method generates an internal load-bearing structure based on the aerodynamic shape and performance requirements of the wing for continuous fiber reinforced composite structures, fully utilizes the reinforcing characteristics of continuous fibers, greatly improves the utilization rate of materials and the specific performance of the structure, effectively solves the material redundancy problem in the forming process of traditional wing structures, reduces the cost of the product, and fills the technical gap of the forming method of composite wing structures.

[0019] The method has good applicability, and by utilizing the controllable forming characteristics of continuous fiber reinforced composite 3D printing technology, the internal structure parameters can be changed according to the load distribution of the wing, so as to realize controllable design of the wing performance and improve the comprehensive performance of the aircraft. This method widens and improves the design freedom and manufacturability of the composite wing structure, and further promotes the development of advanced composite aircraft equipment. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a flowchart of the present application.

[0021] Figure 2 is a schematic diagram of the support point distribution of the internal structure of the wing of the present application.

[0022] Figure 3 is a schematic diagram of path planning of the wing rib of the present application.

[0023] Figure 4 is a schematic diagram of path planning of the wing spar of the present application.

[0024] Figure 5 is a schematic diagram of the connection of the wing rib and the wing spar of the present application.

[0025] Figure 6 is a schematic diagram of the internal structure of the whole wing of the present application.

[0026] Figure 7 is a schematic diagram of 3D printing forming of the whole wing of the present application. DETAILED DESCRIPTION

[0027] The present application will be further described in detail below in combination with the drawings and examples.

[0028] Reference Figure 1 , a 3D printing forming method of a continuous fiber reinforced composite wing structure, comprising the following steps:

[0029] 1) generating a three-dimensional model of the wing structure by airfoil design software or existing airfoil structure, and extracting the wing aerodynamic profile of the three-dimensional model as an important basis for forming the internal structure and the outer skin of the wing to meet the aerodynamic profile requirements of the wing;

[0030] 2) designing the internal structure according to the wing aerodynamic profile obtained in step 1) and the load bearing performance requirements of the wing under working conditions; the internal structure of the wing is composed of wing ribs and wing spars prepared by 3D printing technology of continuous fiber reinforced composite materials, as shown in Figure 2 the wing plan view, the number of wing ribs and wing spars in this embodiment is 11 and 6 respectively, then the node corresponding to the support point can be represented as n ij , i = 1, 2, 3, …, 11; j = 1, 2, 3, …, 6; using the advantage of flexible manufacturing of 3D printing technology, the internal structure of the wing is designed with multiple support points, i.e. Figure 2 the upper and lower skin support points marked in the plan view, wherein the upper skin support points are marked by solid circles in the figure, and the lower skin support points are marked by hollow circles in the figure, by changing the coordinates (x ij , y k ) of the support points n k in the plane, k = 1, 2, 3, …, 66, the adjustment of the internal structure of the wing is realized; in addition, according to the load distribution of the wing, the density p(x k , y k ) of the bearing points in the corresponding plane area is changed to realize the controllable design of the bearing performance under different requirements; the spatial coordinates of the support points n ij are (xk ,y k ,z k ), where z k =z w (x k ,y k )-δ,z w The z-axis coordinate represents the aerodynamic profile of the wing at the support point, and δ represents the thickness of the outer skin of the wing. The support point also serves as the connection point between the spars and ribs, and its coordinate information is used for the forming design of the spars and ribs. Since the spars and ribs are formed using different 3D printing reference surfaces under the same spatial coordinate system, the problem of weak interlayer performance in 3D printing is effectively solved.

[0031] 3) Based on the wing aerodynamic profile information obtained in step 1) and the wing internal structure design parameters obtained in step 2), i.e., the support point coordinate information, path planning is performed on the wing internal structure to generate the 3D printing paths for the wing ribs and spars; the turning radius r of the printing path is determined according to the manufacturing process constraints of continuous fiber reinforced composite material 3D printing. set and scanning spacing h set , make r set ≥R, h set ≤H, where R and H are the minimum fiber corner radius and maximum scanning spacing allowed for 3D printing; based on the spatial coordinates of the support points and manufacturing process constraints, the printing path of the lower rib corresponding to the forming reference plane is first generated. Figure 3 The printing path of the fourth rib in this embodiment is shown. The three-dimensional coordinates of the support points are converted into two-dimensional coordinate information of the printing path, and the printing path is constrained to meet the requirements of 3D printing process; at the same time, Figure 3 The text is marked with the same meaning. Figure 2 Node information n corresponding to the support point position 4j j = 1, 2, 3, ..., 6; the printing path consists of the rib outer contour path based on the wing's aerodynamic profile and the rib filling path based on the coordinates of the internal structural support points; then, based on the connection relationship between the rib and the spar, the same principle is used to plan the spar path, where both the spar's outer contour path and the filling path are planned according to the coordinate positions of the internal wing structure support points obtained in step 2), such as... Figure 4 As shown, the printing path of the wing beam is matched based on the support point positions in the wing rib, where the support point node information n i4 , i=1,2,3,…,11, and Figure 2 , Figure 3 Correspondingly;

[0032] 4) Since continuous fiber reinforced composite material 3D printing technology is an additive manufacturing technology, the total length L of the composite material 3D printing path obtained in step 3) and the weight w of the composite material filament per unit length can be used as the basis for the calculation.l The theoretical weight W of the internal structure of the computer wing in That is, W in =L×w l Furthermore, based on the wing outer contour information obtained in step 1), and according to the wing area S and the composite material weight w per unit area of ​​the outer skin... s The theoretical weight W of the computer wing outer skin sk That is, W sk =S×w s Then the theoretical total weight of the wing structure is W = W in +W sk If the theoretical total weight of the wing structure meets the lightweighting requirements, proceed to the next step of structural forming; if the theoretical total weight of the wing structure does not meet the lightweighting requirements, redetermine the internal structural design parameters through step 2), reduce the support point density ρ to shorten the printing path length L, until the lightweighting requirements of the wing structure are met.

[0033] 5) After the above steps, the 3D printing paths for each wing rib and spars of the internal wing structure are obtained. The corresponding composite material feed parameters and printhead movement speed are input, and the relevant structures are formed using 3D printing equipment. Then, the wing ribs and spars are connected using composite material bonding methods, such as... Figure 5 Support node n shown 44 The diagram shows the connection of the wing ribs and spars. The bonding positions are the support points provided in step 2) and the contact points with the outlines of the wing ribs and spars below them. The same method is used to bond each wing rib and spars, thereby connecting the internal structure of the wing into a whole. Figure 6 As shown, this method can greatly reduce the number of internal parts of the wing, improve the structural utilization rate, and achieve an ultra-lightweight load-bearing structure.

[0034] 6) The outer wing skin is formed based on the internal wing structure, thereby obtaining a lightweight structural wing component made of continuous fiber reinforced composite material, such as... Figure 7 As shown; due to the manufacturing process constraints of continuous fiber reinforced composite material 3D printing, it is necessary to adjust the position of the internal structural support points of the wing to constrain the spacing d between adjacent ribs in the printing direction of the outer skin. r , making d r ≤D, where D is the maximum allowable spacing distance for 3D printing suspended forming; at this point, relying on the characteristics of wing rib support and continuous fiber uninterrupted forming, the first layer of the outer skin can be directly printed on the internal structure of the wing, then the wing angle is flipped and fixed, and the opposite area on the other side of the outer skin is printed; subsequently, the outer skin of the wing is printed layer by layer at varying angles, such as... Figure 7 As shown, the 3D printing of a continuous fiber reinforced composite wing structure was finally achieved.

[0035] The embodiment is directed to a continuous fiber reinforced composite structure, based on the wing aerodynamic shape and load bearing performance requirements, the ribs, spars and outer skin are formed by multi-reference surface forming, to obtain a 3D printing lightweight wing structure configuration as shown in Figure 7 The method not only realizes the fusion of wing structure design and forming process, but also effectively solves the problem of weak performance between layers by using multi-reference surface forming, and finally realizes the controllable design and rapid forming of super-strong quantization, high specific performance and low cost continuous fiber reinforced composite wing structure.

Claims

1. A 3D printing forming method of a continuous fiber-reinforced composite material wing structure, characterized by, The method comprises the following steps: 1) generating a three-dimensional model of the wing structure by airfoil design software or existing airfoil structure generation software, and extracting the wing aerodynamic profile of the three-dimensional model as the basis for forming the wing internal structure and the outer skin; 2) Design the internal structure of the wing based on the aerodynamic profile obtained in step 1) and the load-bearing performance requirements of the wing under working conditions; the internal structure of the wing is composed of ribs and spars made by continuous fiber reinforced composite 3D printing technology, the number of ribs and spars is m and n respectively, then the node corresponding to the support point is represented as n ij , i = 1, 2, 3, …, m; j = 1, 2, 3, …, n; the spatial coordinates of the support point n ij are (x k , y k , z k ), where z k = z w (x k , y k ) - δ, z w represents the z-axis coordinate of the wing aerodynamic profile at the support point position, δ represents the thickness of the wing outer skin; the support point coordinate information is used for the forming design of the spars and ribs, and the spars and ribs are formed using different 3D printing reference surfaces in the same spatial coordinate system; 3) performing path planning on the wing internal structure according to the wing aerodynamic profile information obtained in step 1) and the wing internal structure design parameters, i.e., the support point coordinate information, obtained in step 2), and generating a 3D printing path of the wing ribs and the spars based on manufacturing process constraints; 4) Total length L of the composite material 3D printing path obtained according to step 3) and weight w of the composite material filament per unit length l Theoretical weight W of the internal structure of the computer wing in , that is, W in = L x w l ; in addition, according to the wing area S and the weight w of the composite material per unit area of the outer skin s Theoretical weight W of the outer skin of the computer wing sk , that is, W sk = S x w s , then the theoretical total weight of the wing structure is W = W in + W sk ; if the theoretical total weight of the wing structure meets the lightweight requirement, the next step of structure forming is performed; if the theoretical total weight of the wing structure does not meet the lightweight requirement, the internal structure design parameters are re-determined through step 2) to reduce the support point density p to shorten the printing path length L until the lightweight requirement of the wing structure is met; 5) inputting corresponding composite material feeding parameters and printing nozzle moving speed into the 3D printing path of each wing rib and the spars of the wing internal structure obtained through the above steps, and forming the relevant structure by using a 3D printing device; then, the wing ribs and the spars are connected by using a composite material bonding method, and the bonding position is the support point position provided in step 2), so that the wing internal structure is connected into a whole; 6) forming the wing outer skin on the basis of the wing internal structure, so as to obtain a continuous fiber reinforced composite lightweight structure wing workpiece.

2. The method of claim 1, wherein: The wing internal structure in step 2) adopts a multi-support-point force design, and the support points n ij are changed to realize the adjustment of the wing internal structure; in the coordinate (x k ,y k ) in the wing plane, k = 1, 2, 3, …, m x n-1, m x n, the adjustment of the wing internal structure is realized; in addition, according to the load distribution of the wing, the bearing point density ρ(x k ,y k ) of the corresponding plane area is changed to realize the controllable design of the bearing performance under different requirements.

3. The method of claim 1, wherein, The step 3) is specifically: determining the corner radius r of the printing path according to the manufacturing process constraints of the continuous fiber reinforced composite 3D printing set and the scanning interval h set , so that r set ≥ R, h set ≤ H, wherein R and H are the minimum fiber corner radius and the maximum scanning interval allowed by 3D printing; based on the spatial coordinates of the support points and the manufacturing process constraints, the printing path of the corresponding forming reference surface lower wing rib is first generated, which is composed of a wing rib outer contour path based on the wing aerodynamic contour profile and a wing rib filling path based on the internal structure support point coordinates; then, based on the connection relationship between the wing rib and the spar, the same principle is used to plan the path of the spar, wherein the outer contour path and the filling path of the spar are planned according to the support point coordinate positions of the wing internal structure obtained in step 2).

4. The method of claim 1, wherein, The step 6) is specifically: regulating the position of the internal structure support points of the wing to constrain the interval distance d of the adjacent ribs in the printing direction of the outer skin r , so that d r ≤D, wherein D is the maximum interval distance allowed by the 3D printing suspension forming; at this time, the first layer of the outer skin is directly printed on the internal structure of the wing by relying on the characteristics of the rib support and continuous fiber uninterrupted forming, then the angle of the wing is turned over and fixed, and the opposite area on the other side of the outer skin is printed and formed; thereafter, the outer skin of the wing is printed layer by layer with angle change, and finally the 3D printing forming of the continuous fiber reinforced composite wing structure is realized.

Images