Macro-microstructure mapping method for three-dimensional woven composite aircraft engine blade

Abstract

The invention provides a macro-micro structure mapping method for a three-dimensional woven composite aircraft engine blade, and belongs to the technical field of composite forming. Dividing a solid model corresponding to the to-be-mapped three-dimensional woven composite aircraft engine blade into a table, and determining the aircraft engine blade and model parameters after table division; writing a Python code, and automatically generating a mesoscopic yarn RVE with a certain thickness; embedding the RVE into the macroscopic matrix, twisting or bending, and applying a periodic boundary condition to obtain a twisting form model of the mesoscopic yarn; utilizing affine transformation to rotate and translate the torsion form model of the mesoscopic yarn to complete a local mapping model of RVE; a threshold value is given, all the yarns of all the local mapping models are connected, a variable-thickness mesoscopic yarn macroscopic model is constructed, and therefore macroscopic and mesoscopic structure conversion of the aircraft engine blade is completed. By adopting the technical scheme of the invention, the mapping from the complex-shape variable-thickness entity model to the mesoscopic yarn structure can be quickly realized.

Description

Technical Field

[0001] The present application relates to a macroscopic and microscopic structure mapping method for a three-dimensional woven composite aero-engine blade, belonging to the technical field of composite material forming. Background Art

[0002] Three-dimensional woven carbon fiber reinforced resin-based composites have great application prospects in fan blades of large bypass ratio commercial turbofan engines due to their comprehensive advantages in mechanical properties and complex component forming. Due to the unique interlayer interlocking structure, three-dimensional woven composites have significant advantages over traditional laminate composites. From the perspective of mechanical properties, three-dimensional woven composites have higher resistance to delamination, impact resistance and damage resistance (notch insensitivity). From the perspective of design, three-dimensional woven composites have better designability, and fiber preforms can be designed according to actual needs, and the mechanical properties of each part and different directions can be customized according to specific requirements. Therefore, three-dimensional woven composites are increasingly used in aviation and aerospace structures.

[0003] The outer contour of the fan blade's special-shaped structure has a large torsional geometry and its thickness also changes. During the molding process, its complex shape and variable thickness structure will cause the thickness shape of the internal mesoscale yarns to change and the path deflection. The irregular distribution of the mesoscale yarns poses a challenge to studying the material properties of this typical composite structure. Based on Micro-CT scanning, a model that is almost completely consistent with the actual internal structure of the material can be reconstructed, but the modeling cost is high and the modeling efficiency is too low. In addition, the image quality of the Micro-CT scan depends largely on the size of the structure, and it is difficult to observe the microscopic morphology of the internal yarns of the entire complex structure. Overly detailed models are not conducive to the numerical analysis of mechanical properties. Therefore, the reconstruction method of Micro-CT images is difficult to establish large-scale models and can only study existing structures. Once the torsion angle of the twisted structure changes, a new composite structure needs to be manufactured for scanning. Its actual application in mechanical analysis is relatively small. The "microstructure-mesostructure-embedded matrix torsional deformation-affine transformation to obtain a twisted body with a constant cross-section" approach (e.g., Mesoscale modeling of woven composite twisted structures combining digital element embedded model and affine transform, Z. Liu et al. Composites Science and Technology 249 (2024) 110504) suffers from long mapping cycles and is mostly applicable to macroscopic geometric structures with less stringent precision requirements. Therefore, developing a method for mapping the macro- and mesostructures of complex, variable-thickness 3D woven preforms is crucial. Summary of the Invention

[0004] In view of this, the present application provides a macro-micro structure mapping method for three-dimensional woven composite aero-engine blades, which realizes the rapid mapping of complex shape and variable thickness entities such as aircraft engine fan blades (abbreviated as: aero-engine blades) to micro yarn structures.

[0005] Specifically, this application is implemented through the following solutions:

[0006] A macro-microstructure mapping method for a three-dimensional woven composite aero-engine blade is described, comprising the following steps:

[0007] Step 1: Divide the solid model corresponding to the aero-engine blade to be mapped into a table, determine the weaving structure, warp / weft thickness product, yarn interlayer density, warp / weft density of the aero-engine blade, and clearly divide the thickness, adjacent surface torsion angle and position coordinates relative to the coordinate origin of the obtained table.

[0008] Preferably, the woven structure is a plain weave structure, and the warp / weft yarn transverse thickness products are 0.942 mm 2 , 1.57mm 2 The yarn interlayer density (the number of yarn layers contained in unit thickness) is 5.4 layers / cm, and the warp / weft yarn density is 2.6 yarns / cm and 2.5 yarns / cm.

[0009] Step 2: Write Python code to automatically generate a representative volume element (RVE) of a certain thickness of micro-yarn.

[0010] Preferably, along the increasing thickness direction of the aeroengine blade to be mapped, the representative volume elements (RVEs) are divided into three groups according to thickness: the smallest grid thickness, the largest grid thickness, and the largest grid thickness. More preferably, the smallest grid thickness corresponds to a thickness range of 12-14.4 mm, the smallest grid thickness corresponds to a thickness range of 14.4-17.5 mm, and the largest grid thickness corresponds to a thickness range of 17.5-20 mm.

[0011] Step three: embed the representative volume unit of the generated micro-yarn into a macroscopic matrix, twist or bend it, and apply periodic boundary conditions to obtain a torsional morphological model of the micro-yarn.

[0012] Preferably, the twist angle It is 8.4°.

[0013] Taking a unit cell formed by embedding a representative volume unit into a macroscopic matrix as an example, the surface along the x-direction is denoted as F1, the surface along the y-direction is denoted as F2, the surface opposite to F1 is denoted as F3, and the surface along the z-direction is denoted as F4. Surface F4 is fixed, and the periodic boundary conditions of surfaces F1, F2, and F3 satisfy:

[0014]

[0015] Among them, the corresponding parameters in the above formula are: is the displacement of the kth section point on surface F1 along the x, y, and z directions, is the coordinate of the kth section point on surface F1, is the angle of twist, a and b are the dimensions of the unit cell. The same applies to F2 and F3.

[0016] The representative volume element of the mesoscopic yarn is embedded in the macroscopic matrix to form a hybrid element model, in which the internal node displacements of the mesoscopic yarn and the internal node displacements of the macroscopic matrix are bound to each other through an interpolation function.

[0017] By twisting or bending the hybrid unit model and applying deformation boundary conditions, the macroscopic matrix can drive the internal microscopic yarn to deform, thereby generating a torsional morphological model of the microscopic yarn with a certain macroscopic torsion or bending angle.

[0018] The interpolation function satisfies:

[0019]

[0020] u micro is the location vector of the microscopic yarn node, is the displacement vector of the i-th macro node, ξ, η, ζ are local coordinates, and their value range is [-1, 1].

[0021] Step 4: Use affine transformation to rotate and translate the torsional morphological model of the micro-yarn to complete the local mapping model of the representative volume unit of the micro-yarn.

[0022] Preferably, the rotation angle θ is 9.6° and the translation distance dy is 30 mm.

[0023] According to the above method, the representative volume units of micro-yarns of different thicknesses are subjected to affine transformation respectively to obtain multiple sets of local mapping models.

[0024] In step five, a threshold is given, all yarns in each local mapping model are connected, and a macroscopic model of a variable thickness microscopic yarn is constructed, thereby completing the macroscopic and microscopic structural transformation of the three-dimensional woven preform.

[0025] The given threshold needs to ensure that the cross-sectional diameter error of connecting each local mapping model is within ±10% to 15%, and the connected corresponding cross-sectional shapes have the same cross-sectional shape.

[0026] Compared with the existing technology, the technical advantages or beneficial effects of this application are:

[0027] Compared with the conventional microstructure-mesostructure-embedded matrix torsional deformation-affine transformation to obtain a torsion body of equal cross-section, the present application can realize the mapping of a complex shape variable thickness solid model to a complex shape variable thickness mesoscopic yarn structure. In the process of constructing the mesoscopic yarn macroscopic model, the variable cross-section, variable thickness solid three-dimensional woven composite aero-engine blade is taken as the object, and it is meshed. Then, according to the thickness of each grid, a threshold is set, and Python automated modeling is used to directly generate ideal mesoscopic unit cells of various thicknesses, that is, representative volume units of mesoscopic yarns, which are embedded in the macroscopic matrix for closed torsional deformation, and further affine transformation (rotation and translation) of unit cells of different thicknesses is performed to the specified area to complete the rapid establishment of the variable thickness mesoscopic yarn macroscopic model. In this mapping process, while performing affine transformation through RVE of different thicknesses, the thickness change of the yarn structure can also be achieved, which provides help for the rapid establishment of the complex shape variable thickness yarn structure, so as to facilitate the subsequent study of material properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0029] Figure 1 This is a comparison diagram of the solid model before and after meshing in this application;

[0030] Figure 2 The torsional morphology model forming process of the microscopic yarn in this application;

[0031] Figure 3 This is the affine transformation process diagram in this application;

[0032] Figure 4 This is a structural comparison of the entity model before and after mapping in this application;

[0033] Figure 5 Schematic diagram of the cross-sectional structure of the macroscopic model of the variable thickness mesoscopic yarn of this application;

[0034] Figure 6 is the periodic boundary condition for the hybrid element model.

[0035] Numbers in the figure: 1. Solid model; 2. Meshed solid model; 21. Minimum thickness RVE; 22. Larger thickness RVE; 23. Maximum thickness RVE; 3. Macro matrix; 4. Hybrid unit model; 5. Torsion morphology model; 51. Orthographic angle model; 52. Rotation angle model; 53. Local mapping model; 6. Variable thickness micro-yarn macro model; 61. The cross section at one end corresponding to the minimum thickness RVE; 62. The cross section at one end corresponding to the maximum thickness RVE. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the technical solutions in the embodiments of this application will be further described in detail below in conjunction with the drawings in the embodiments of this application. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit the technical solutions of this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of this application.

[0037] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it may be located directly or indirectly on the other component. When a component is referred to as being "connected to" another component, it may be directly or indirectly connected to the other component. The directions or positions indicated by the terms "upper," "lower," "left," "right," "front," "back," "vertical," "horizontal," "top," "bottom," "inside," and "outside" are based on the directions or positions shown in the accompanying drawings and are for ease of description only. They should not be construed as limitations on the present technical solution.

[0038] In addition, the terms "first" and "second" are used only for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly specifying the number of technical features. "Multiple" means two or more, unless otherwise specifically defined.

[0039] Example 1

[0040] The present application provides a macro- and micro-structure mapping method for a three-dimensional woven composite aero-engine blade. The embodiments of the present application are described below in conjunction with the accompanying drawings.

[0041] See Figure 1 , Figure 1 The solid model 1 of the object to be mapped in this embodiment is shown as follows: a three-dimensional woven composite aero-engine blade. Figure 1 It can be seen that the solid model 1 is a variable thickness and variable cross-section structure. Figure 1 As a benchmark) the thickness increases.

[0042] The macro- and micro-structures of the three-dimensional woven composite aero-engine blade are mapped as follows:

[0043] Step 1: Divide the solid model 1 of the aero-engine blade to be mapped into a table to obtain a gridded solid model 2, determine the weaving structure, warp / weft thickness product, yarn interlayer density, warp / weft density of the three-dimensional woven composite aero-engine blade, and clearly divide the thickness of the obtained table, the torsion angle of adjacent surfaces, and the position coordinates relative to the coordinate origin.

[0044] Combine Figure 1 、 Figure 3 The upper left corner of the macro model 1 of the aero-engine blade is set as the relative coordinate origin xyz. The cross section of the macro model 1 of the aero-engine blade changes from 20×100mm on the right to 12×92mm on the left. The torsion angle θ, that is, the torsion angle of the right section relative to the left section, is 30°, the bending is 0°, the woven structure is a plain weave structure, and the warp / weft yarn transverse thickness products are 0.942mm respectively. 2 , 1.57mm 2The yarn interlayer density is 5.4 layers / cm, the warp density is 2.6 yarns / cm, and the weft density is 2.5 yarns / cm. The thickness range corresponding to the minimum grid thickness of the obtained meshed solid model 2 is 12mm~14.4mm, the thickness range corresponding to the smaller grid thickness is 14.4mm~17.5mm, and the thickness range corresponding to the maximum grid thickness is 17.5mm~20mm.

[0045] Step 2: Write Python code to automatically generate a representative volume element (RVE) of a certain thickness of micro-yarn.

[0046] In this application, Python code replaces the Micro-CT scanning method to obtain the yarn structure. The code writing needs to follow the unit cell geometric modeling principles. For example, the center path of the yarn needs to follow the periodicity consistent with the actual textile structure and the cross-sectional shape of the yarn needs to maintain continuous deformation along the center line. The code writing also needs to follow the material property embedding principle, such as defining the fiber direction vector field within the unit cell and calculating the local porosity based on the yarn compression rate. The code writing also needs to follow the periodic boundary processing principle. For example, the geometric vertices on the unit cell boundary must be strictly matched to ensure seamless splicing of the array.

[0047] Combine Figure 1 In this embodiment, the representative volume units are divided into three thickness levels from left to right: the first four columns on the left are defined as the minimum thickness RVE 21, that is, the thickness range of 12 mm to 14.4 mm in the above text; the middle four columns are defined as the larger thickness RVE 22, that is, the thickness range of 14.4 mm to 17.5 mm in the above text; and the four columns on the right are defined as the maximum thickness RVE 23, that is, the thickness range of 17.5 mm to 20.0 mm in the above text.

[0048] Step three: The generated representative volume element (RVE) of the meso-yarn is embedded in the macro-matrix 3 to form a hybrid unit model 4. In this hybrid unit model 4, the internal node displacements of the meso-yarn and the internal node displacements of the macro-matrix are bound to each other through an interpolation function. The hybrid unit model 4 is twisted and periodic boundary conditions are applied. The macro-matrix 3 causes the internal meso-yarn to deform, thereby generating a torsional morphological model 5 of the meso-yarn with a certain macro-twist or bending angle.

[0049] by Figure 2 For example, a relatively thick RVE 22 is embedded in a macroscopic matrix 3 to obtain a hybrid unit model 4. The hybrid unit model 4 is twisted and a periodic boundary condition is applied to obtain a torsional morphological model 5 of the microscopic yarn.

[0050] The torsion parameters are set as follows: torsion angle 8.4°, friction coefficient 0.3.

[0051] Combine Figure 6, taking the mixed unit model 4 as an example, in one of the unit cells, the length (x), width (y), and height (z) are denoted as a, b, and c, which are the unit cell dimensions. That is, the twist angle is 8.4° as mentioned above. The surface along the x-direction is recorded as F1, the surface along the y-direction is recorded as F2, the surface opposite to F1 is F3, and the surface along the z-direction is recorded as F4.

[0052] Fix surface F4, and the periodic boundary conditions of surfaces F1, F2, and F3 satisfy:

[0053]

[0054] in, is the displacement of the kth section point on surface F1 along the x, y, and z directions, are the coordinates of the kth section point on surface F1, and the same applies to F2 and F3.

[0055] The same method is also used for RVEs of other thicknesses to obtain the torsional morphological models corresponding to their respective thicknesses.

[0056] In the above steps, the interpolation function satisfies:

[0057]

[0058] u micro is the displacement vector of the microscopic yarn node, is the displacement vector of the ith macro node, ξ, η, ζ∈[-1,1], are local coordinates.

[0059] Step 4: Using affine transformation, the torsional morphological model of the micro-yarn is rotated and translated to complete the local mapping model 53 of the representative volume unit of the micro-yarn.

[0060] Combine Figure 3 Taking the torsional morphological model 5 corresponding to the thicker RVE 22 as an example, the initial structure in the direction a→b in the figure (mainly referring to the thickness in this case) is consistent. The torsional morphological models corresponding to all RVEs in this direction are obtained by the above-mentioned rotation and translation affine transformation of the thicker RVE 22.

[0061] Pick Figure 3 The dotted box of the torsion morphological model 5 is used as the front view to illustrate the above-mentioned rotation and translation process: the front view angle model 51 is first rotated to obtain the rotation angle model 52, the rotation angle is 9.6°, and the coordinates are also changed from yz of the front view to y′-z′; the rotation angle model 52 is translated to obtain the local mapping model 53, and the translation distance dy is set to 30 mm. The coordinates remain unchanged during the translation process, that is, they remain y′-z′.

[0062] An affine transformation is a linear transformation in geometry, consisting of a combination of linear transformations (such as rotation, scaling, and shearing) and translation. It preserves the straightness of a figure (a straight line remains a straight line after transformation) and parallelism (parallel lines remain parallel after transformation). The rotations and translations mentioned above are both affine transformations.

[0063] According to the above method, the torsional morphological models 5 corresponding to the representative volume units of micro-yarns of different thicknesses are subjected to affine transformation respectively to obtain multiple groups of local mapping models.

[0064] Step 5: Given a threshold, all yarns in each local mapping model are connected to construct a variable thickness micro-yarn macro model 6, thereby completing the macro-micro structure conversion of the three-dimensional woven preform.

[0065] Figure 4 In the variable thickness micro-yarn macro-model 6 structure, the warp yarn elliptical cross-section size is 2×0.6mm, the warp yarn density is 2.6 yarns / cm; the weft yarn elliptical cross-section size is 2×1mm, the weft yarn density is 2.5 yarns / cm; the interlayer spacing (vertical distance between adjacent yarns) is 1mm.

[0066] In order to clearly express the thickness variation of the above-mentioned variable thickness micro-yarn macro model 6, its minimum thickness end section (NN) and maximum thickness end section (MM) are schematically illustrated. The results are shown in Fig. Figure 5 As shown, these correspond to cross-section 61 at the end with the minimum thickness RVE and cross-section 62 at the end with the maximum thickness RVE. This indirectly demonstrates that the micro-yarn macro-model 6 obtained in this case is a variable cross-section structure. In this step, the thresholds are set to ensure that the diameter error of the connected cross-sections is within ±10% to 15%, and that the connected cross-sections have the same cross-sectional shape.

[0067] The above method can be used to obtain a variable thickness micro-yarn macro-model 6 that is mapped to a macro-solid model 1 of any complex shape, such as the aircraft engine blade in this case.

[0068] This application enables the mapping of complex, variable-thickness solid models to complex, variable-thickness micro-yarn structures. During the construction of the micro-yarn macro-model 6, a three-dimensional, variable-cross-section, variable-thickness woven composite aero-engine blade is used as the object, which is meshed. Then, based on the thickness of each mesh, a threshold is set. Using Python automated modeling, ideal micro-unit cells of various thicknesses are directly generated, i.e., the representative volume elements (RVEs) of the micro-yarns. These cells are then embedded in a macro-matrix 3 and torsionally deformed. The units of varying thicknesses are then affine-transformed (rotated and translated) to a specified region, completing the rapid construction of the variable-thickness micro-yarn macro-model 6. During this mapping process, the affine transformation of the RVEs of varying thicknesses simultaneously achieves thickness variation in the yarn structure, facilitating the rapid construction of complex, variable-thickness yarn structures and facilitating subsequent material property research. Compared to the "microstructure-microstructure-embedded matrix torsionally deformed-affine transformation to obtain a torsion body of constant cross-section" approach, the structural mapping cycle for the same preform can be reduced by over 30%.

[0069] The above-described embodiments merely represent several feasible implementation methods of the present invention. The description thereof is relatively specific and detailed, but it should not be understood as limiting the scope of the invention. The embodiments are not intended to limit the scope of protection in the claims of the present invention. For those skilled in the art, various modifications and improvements can be made without departing from the concept of the present invention. Any equivalent implementation or modification that does not depart from the scope of the present invention should be included in the technology of the present invention.

Claims

1. A macro-microstructure mapping method for a three-dimensional woven composite aero-engine blade, characterized in that: Here are the steps: Step 1: Divide the solid model corresponding to the aero-engine blade to be mapped into a table, determine the weaving structure, warp / weft thickness product, yarn interlayer density, warp / weft density of the aero-engine blade, and clearly divide the thickness, adjacent surface torsion angle, and position coordinates relative to the coordinate origin of the obtained table; Step 2: Write Python code to automatically generate representative volume units of micro-yarns of a certain thickness; Step 3: embedding the representative volume unit of the generated micro-yarn into a macro-matrix, twisting or bending it, and applying periodic boundary conditions to obtain a torsional morphological model of the micro-yarn; Step 4: Using affine transformation, the torsional morphological model of the micro-yarn is rotated and translated to complete the local mapping model of the representative volume unit of the micro-yarn; In step five, a threshold is given, all yarns in each local mapping model are connected, and a macroscopic model of variable thickness microscopic yarns is constructed, thereby completing the macroscopic and microscopic structural transformation of the three-dimensional woven composite aero-engine blade.

2. The macro-microstructure mapping method of a three-dimensional woven composite aero-engine blade according to claim 1, characterized in that: In step 1, the three-dimensional woven preform is an aircraft engine blade, and its woven structure is a plain weave structure, and the warp / weft yarn transverse thickness product is 0.942 mm 2 , 1.57mm 2 The yarn interlayer density is 5.4 layers / cm, and the warp / weft yarn density is 2.6 yarns / cm and 2.5 yarns / cm.

3. The macro-micro structure mapping method of a three-dimensional woven composite aero-engine blade according to claim 1, characterized in that: In step 2, along the increasing thickness direction of the aero-engine blade to be mapped, the representative volume units are divided into three groups: the smallest grid thickness, the larger grid thickness and the largest grid thickness. The thickness range corresponding to the smallest grid thickness is 12 to 14.4 mm, the thickness range corresponding to the smaller grid thickness is 14.4 to 17.5 mm, and the thickness range corresponding to the largest grid thickness is 17.5 to 20 mm.

4. The macro-microstructure mapping method of a three-dimensional woven composite aero-engine blade according to claim 1, characterized in that: In step 3, the twist angle It is 8.4°.

5. The macro-micro structure mapping method of a three-dimensional woven composite aero-engine blade according to claim 1, characterized in that: In step 3, the representative volume unit is embedded in a unit cell formed by the macroscopic matrix. The surface along the x-direction is denoted as F1, the surface along the y-direction is denoted as F2, and the surface along the z-direction is denoted as F4. The surface opposite to F1 is F3. Surface F4 is fixed, and the periodic boundary conditions of surfaces F1, F2, and F3 meet the following conditions: Among them, the corresponding parameters in F1 above are: is the displacement of the kth section point on surface F1 along the x, y, and z directions, is the coordinate of the kth section point on surface F1, is the torsion angle, a and b are the dimensions of the unit cell; the same applies to the F2 and F3 parameters.

6. The macro-microstructure mapping method of a three-dimensional woven composite aero-engine blade according to claim 1, characterized in that: In step 3, the representative volume unit of the mesoscopic yarn is embedded in the macroscopic matrix to form a hybrid unit model. In this hybrid unit model, the representative volume unit of the mesoscopic yarn is embedded in the macroscopic matrix to form a hybrid unit model. In this hybrid unit model, the internal node displacement of the mesoscopic yarn and the internal node displacement of the macroscopic matrix are bound to each other through an interpolation function. The interpolation function is set to be bound to each other through an interpolation function, and the interpolation function satisfies: u micro is the displacement vector of the microscopic yarn node, is the displacement vector of the i-th macro node, ξ, η, ζ are local coordinates, and their value range is [-1,1].

7. The macro-microstructure mapping method of a three-dimensional woven composite aero-engine blade according to claim 1, characterized in that: In step 4, the rotation angle θ is 9.6°.

8. The macro-microstructure mapping method of a three-dimensional woven composite aero-engine blade according to claim 1, characterized in that: In step 4, the translation distance dy is 30 mm.

9. The macro-microstructure mapping method of a three-dimensional woven composite aero-engine blade according to claim 1, characterized in that: In step five, the given threshold ensures that the diameter error of the cross-sections connecting the local mapping models is within ±10-15%, and the corresponding cross-sections connected have the same cross-sectional shape.

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