Optimization method for placement trajectory of each layer of composite laminate with openings

Abstract

A method for optimizing the laying trajectory of laying tapes of each layer of a composite laminate with an opening is disclosed. The method is designed to construct a local coordinate system with the center of the opening on the composite laminate as the origin, and to define the laying trajectory of the laying tapes of each layer of the composite laminate based on the streamline cluster of the ideal fluid cylinder. This can reduce the number of laying tapes of each layer cut by the opening and reduce the degree of damage to the force transmission path. In addition, a global coordinate system is established with the center of the opening on the composite laminate as the origin. The laying tape laying angles corresponding to each finite element mesh of the geometric model of the composite laminate in the local coordinate system are transformed into the corresponding laying tape laying angles in the global coordinate system by coordinate transformation, and finite element calculation is performed. Taking the strength of the composite laminate as the optimization target, the laying trajectory of the laying tapes of each layer of the composite laminate is obtained, and the laying trajectory of each layer of the laying tape is optimized to ensure the strength of the composite laminate.

Description

Technical Field

[0001] The present application belongs to the technical field of optimized design of laying trajectories of laying tapes of each layer of a composite material laminate with openings, and specifically relates to a method for optimizing the laying trajectories of laying tapes of each layer of a composite material laminate with openings. Background Art

[0002] Composite laminates have excellent mechanical properties and are widely used in engineering. Currently, most layers of composite laminates are formed by laying tapes in a straight line side by side at a certain angle, which cannot fully utilize the directional characteristics of the composite tapes. When there are openings in the composite laminates, a large number of laying tapes in each layer will be cut off, the force transmission lines of the structure will be damaged, and it will cause a sudden change in the local stiffness of the structure, resulting in stress concentration in the edge area of ​​the opening, which significantly reduces the strength of the composite laminates.

[0003] This application is proposed in view of the above-mentioned technical defects.

[0004] It should be noted that the disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention, and it does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this application, the above background technology should not be used to evaluate the novelty and creativity of this application. Summary of the Invention

[0005] The purpose of the present application is to provide a method for optimizing the laying trajectory of each layer of a composite material laminate with openings, so as to overcome or alleviate at least one of the existing technical defects.

[0006] The technical solution of this application is:

[0007] A method for optimizing the placement trajectory of each layer of a composite material laminate with an opening, comprising:

[0008] Establish a global coordinate system with the center of the hole in the composite laminate as the origin;

[0009] With the center of the hole in the composite laminate as the origin, a local coordinate system is constructed. Based on the streamline cluster of the ideal fluid around the cylinder, the placement trajectory of each layer of the composite laminate is defined.

[0010] Construct the geometric model of the composite laminate, perform finite element meshing, and calculate the coordinates of each finite element mesh in the global coordinate system;

[0011] Corresponding to each layer of the composite laminate, the coordinates of each finite element grid in the global coordinate system are transformed into the coordinates of the local coordinate system, and the placement tape placement angle corresponding to each finite element grid in the local coordinate system is calculated using the placement tape placement trajectory of each layer of the composite laminate;

[0012] For each layer of the composite laminate, the placement tape angle corresponding to each finite element grid in the local coordinate system is transformed into the corresponding placement tape angle in the global coordinate system;

[0013] The laying tape placement angles corresponding to the finite element grids in the global coordinate system for each layer of the composite laminate are assigned to the geometric model, and finite element calculations are performed. Taking the strength of the composite laminate as the optimization target, the laying tape placement trajectories of each layer of the composite laminate are obtained.

[0014] According to at least one embodiment of the present application, in the above-mentioned method for optimizing the placement trajectory of the placement tapes of each layer of a composite laminate with an opening, the local coordinate system is constructed with the center of the opening on the composite laminate as the origin, and the placement trajectory of the placement tapes of each layer of the composite laminate is defined based on the cluster of streamlines of the ideal fluid flow around the cylinder, specifically as follows:

[0015] <Γ k |θ k >, (k=1, 2...N);

[0016] in,

[0017] Γ k The control parameters of the stream function of the ideal fluid streamline cluster around the cylinder for the kth layer of the composite laminate with the placement trajectory;

[0018] θ k is the deflection angle of the local coordinate system of the kth layer of the composite laminate relative to the global coordinate system;

[0019] N is the number of layers of the composite laminate.

[0020] According to at least one embodiment of the present application, in the above-mentioned method for optimizing the placement trajectory of each layer of the composite laminate with an opening, the coordinates of each finite element mesh in the global coordinate system are transformed into coordinates in the local coordinate system corresponding to each layer of the composite laminate, specifically:

[0021]

[0022] in,

[0023] x and y are the coordinates of each finite element mesh in the global coordinate system;

[0024] x' k 、y'k are the coordinates of each finite element mesh in the local coordinate system corresponding to the kth layer of the composite laminate.

[0025] According to at least one embodiment of the present application, in the above-mentioned method for optimizing the placement trajectory of the placement tape of each layer of the composite laminate with an opening, the placement tape placement angle corresponding to each finite element mesh in the local coordinate system is calculated using the placement trajectory of the placement tape of each layer of the composite laminate, specifically:

[0026]

[0027] in,

[0028] is the placement angle of the lay-up tape corresponding to the kth layer of the composite laminate, for each finite element mesh in the local coordinate system;

[0029] ψ k The kth layer of the composite laminate is laid with a laying trajectory and the stream function of the streamline cluster of an ideal fluid flowing around a cylinder.

[0030] According to at least one embodiment of the present application, in the above-mentioned method for optimizing the laying trajectory of each layer of the composite material laminate with openings,

[0031]

[0032] According to at least one embodiment of the present application, in the above-mentioned method for optimizing the placement trajectory of the placement tape of each layer of the composite laminate with an opening, the placement tape placement angle corresponding to each finite element mesh in the local coordinate system is transformed into the corresponding placement tape placement angle in the global coordinate system for each layer of the composite laminate, specifically:

[0033]

[0034] in,

[0035] is the placement tape angle corresponding to the kth layer of the composite laminate for each finite element mesh in the global coordinate system.

[0036] According to at least one embodiment of the present application, in the above-mentioned method for optimizing the laying trajectory of the laying tapes of each layer of the composite laminate with an opening, the laying trajectory of the laying tapes of each layer of the composite laminate is obtained by taking the strength of the composite laminate as the optimization target, specifically as follows:

[0037]

[0038] in,

[0039] F f is the strength of the composite laminate;

[0040] Γ min , Γ max The minimum and maximum setting values ​​of the flow function control parameters of the ideal fluid flow streamline cluster around the cylinder for laying the laying trajectory of each layer of the composite laminate;

[0041] θ min ,θ max The minimum and maximum setting values ​​for the deflection angle of the local coordinate system of each layer of the composite laminate relative to the global coordinate system.

[0042] This application has at least the following beneficial technical effects:

[0043] Provided is a method for optimizing the laying trajectory of laying tapes of each layer of a composite material laminate with an opening. The method is designed to construct a local coordinate system with the center of the opening on the composite material laminate as the origin, and to define the laying trajectory of the laying tapes of each layer of the composite material laminate based on a cluster of streamlines around an ideal fluid cylinder. This method can reduce the number of laying tapes of each layer cut by the opening and reduce the degree of damage to the force transmission path. In addition, a global coordinate system is established with the center of the opening on the composite material laminate as the origin. Coordinate transformation is used to transform the laying tape laying angles corresponding to each layer of the composite material laminate and finally each finite element mesh of the geometric model of the composite material laminate in the local coordinate system to the corresponding laying tape laying angles in the global coordinate system. Finite element calculation is performed, and the strength of the composite material laminate is taken as the optimization target to obtain the laying trajectory of the laying tapes of each layer of the composite material laminate, thereby optimizing the laying trajectory of the laying tapes of each layer and ensuring the strength of the composite material laminate. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 1 is a flow chart of a method for optimizing the laying trajectory of each layer of a composite material laminate with openings provided in an embodiment of the present application;

[0045] Figure 2 is a schematic diagram of the local coordinate system and the global coordinate system provided in an embodiment of the present application;

[0046] Figure 3 is a schematic diagram of the geometric dimensions of the composite material laminate provided in the embodiment of the present application;

[0047] Figure 4 is a schematic diagram of establishing a finite element model of a composite laminate provided in an embodiment of the present application;

[0048] Figure 5The present invention provides a schematic diagram of the effect of the optimized laying trajectory of each layer of the composite material laminate with openings provided by the embodiment of the present application on the strength of the composite material laminate compared with the existing laying trajectory.

[0049] In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. In addition, the drawings are only used for illustrative purposes and should not be understood as limitations on this patent. DETAILED DESCRIPTION

[0050] To make the technical solution and its advantages of the present application clearer, the technical solution of the present application will be described in further detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of the present application and are only used to explain the present application, not to limit the present application. It should be noted that, for ease of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0051] In addition, unless otherwise defined, the technical or scientific terms used in the description of this application should have the ordinary meanings understood by those of ordinary skill in the art to which this application belongs. The words "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer" used in the description of this application are only used to indicate relative directions or positional relationships, and do not imply that the device or component must have a specific orientation, be constructed, or operate in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. Therefore, they should not be understood as limitations on this application. The words "first," "second," "third," and similar terms used in the description of this application are used only for descriptive purposes to distinguish different components and should not be understood to indicate or imply relative importance. The words "one," "an," or "the" used in the description of this application should not be understood as absolute limitations on quantity, but should be understood as meaning the presence of at least one. The words "include" or "comprises" used in the description of this application mean that the element or object listed before the word includes the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0052] In addition, it should be noted that, unless otherwise clearly stipulated and limited, the words "install", "connect", "connect" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or a connection between two components. Technical personnel in the field can understand their specific meanings in this application according to the specific circumstances.

[0053] The following is combined with Figures 1 to 5 This application is described in further detail.

[0054] The streamline cluster of ideal fluid flowing around a cylinder, such as Figure 2 As shown, the velocity direction of the uniform straight flow is along the x' axis, and the streamline cluster equation in the x'oy' local coordinate system is as follows:

[0055]

[0056] in,

[0057] ψ is the stream function;

[0058] Γ is the control parameter, which determines the shape of the streamline cluster;

[0059] Const is a constant that determines the position of the streamline.

[0060] The local coordinate system x'oy' can be obtained by rotating the global coordinate system xoy, as shown in Figure 2 As shown, for any point P(x,y) in the global coordinate system xoy, the coordinates (x',y') of point P in the local coordinate system x'oy' can be obtained:

[0061]

[0062] in,

[0063] θ is the angle between the x' axis and the x axis, that is, the rotation angle between the local coordinate system x'oy' and the global coordinate system xoy.

[0064] According to the streamline cluster equation (1), the tangent direction vector of the point P(x',y') on the streamline can be determined:

[0065]

[0066]

[0067] The angle between the tangent direction at point P(x',y') and the x' axis can be determined

[0068]

[0069] Corresponding to point P, the angle between the tangent direction of the streamline in the global coordinate system xoy and the x-axis

[0070]

[0071] If the geometric dimensions of the composite laminate are given, such as Figure 3 As shown, the length is L, the width is W, the aperture of the hole is D, and the number of layers of the given composite laminate is N, the material properties and the load and boundary conditions of the opening, it can be assumed that the laying trajectory parameter of the composite laminate is <Γ k |θ k >(k=1,2…N).

[0072] In commercial finite element software, the geometric model of the composite laminate is constructed, the global mesh size is set, and the mesh is divided using shell elements.

[0073] Based on the generated finite element mesh model file, the node number and node coordinates corresponding to each unit can be read. Through the node coordinates of each unit, the coordinates (x, y) of each finite element mesh in the global coordinate system xoy can be calculated.

[0074] According to the laying trajectory parameters of each layer of composite laminate <Γ k |θ k > and the coordinates (x, y) in the global coordinate system xoy, the coordinates of x'oy', the tangent direction vector, and the angle between the tangent direction and the x' axis in each layer's local coordinate system can be determined in turn by equations (2) to (4). Then, substituting into (5), we can get the laying angle of the laying belt: Therefore, a one-to-one correspondence between the unit number of each layer of the composite laminate and the laying angle of the laying tape, that is, the angle field, is established. A total of N angle fields are assigned to the composite laminate, and the load and boundary conditions are set to complete the strength analysis of the composite laminate. The strength F of the composite laminate under different load conditions can be obtained. f .

[0075] The present invention discloses a method for optimizing the laying trajectory of each layer of composite material laminate, which uses the streamline shape control parameters of the laying trajectory of each layer of composite material laminate and the deflection angle of the coordinate system as design variables <Γ k |θ k >, the strength F of the composite laminate f To optimize the objectives, the details are as follows:

[0076]

[0077] In a specific embodiment, the composite laminate has L=150 mm, W=100 mm, D=20 mm, a total number of plies N=2, a single layer thickness of 0.155 mm, and is prepared by a 3D printing process. The material performance parameters are longitudinal modulus 118 GPa, transverse modulus 8980 MPa, shear modulus 4210 MPa, in-plane Poisson's ratio 0.306, longitudinal tensile strength 1835 MPa, longitudinal compressive strength 1296 MPa, transverse tensile strength 82.5 MPa, transverse compressive strength 240 MPa, and shear strength 166 MPa. The load boundary conditions are that the loading edges on the left and right sides are fixed support boundary conditions, and a tensile displacement of 1 mm in the x-axis direction is applied to the right loading edge.

[0078] According to the method for optimizing the laying trajectory of each layer of a composite material laminate with openings disclosed in this application, the laying trajectory of each layer of the laying tape can be optimized by referring to the following steps:

[0079] 1) Set the initial laying tape laying trajectory parameters to: [<50|30°> / <50|-30°>].

[0080] 2) In the finite element software ABAQUS, the geometric model and material model of the composite laminate are established. The composite laminate is modeled using the shell element S4R, with 80 elements set around the opening and the number of model grids being 2200. Figure 4 As shown, the material model is set to a single-layer plate with a single-layer thickness of 0.155 mm.

[0081] 3) Based on the generated finite element mesh model file, read the number and coordinates of the corresponding nodes of each unit. Through the node coordinates of each unit, the coordinates of each finite element mesh in the overall coordinate system can be calculated. Then, the laying angle of each layer of laying tape is determined by (2) to (5), and a one-to-one correspondence between the unit number of each layer and the laying angle of the laying tape is established, that is, the angle field. The obtained angle field is assigned to the composite laminate; for example:

[0082] The coordinates of the finite element mesh in the global coordinate system are (5, 10). For the first layer, the laying trajectory parameter is <50|30°>. From formula (2), the coordinates of the first layer in the local coordinate system are (9.33, 6.16). Substituting into formula (3) yields the direction vector in the local coordinate system (0.843, -0.368). Substituting into formula (4) yields the angle between the laying direction of the laying tape and the x' axis. Substituting (5) into the laying angle, we can get

[0083] 4) Set the load boundary conditions and perform tensile failure analysis to obtain the strength F of the composite laminate. f .

[0084] 5) Steps 1) to 4) are converted into a parametric analysis script based on Python language to facilitate the analysis of the strength of composite laminates under different placement tape placement trajectory parameters.

[0085] 6) Set parameter range: Γ k ∈[0,100]θ k ∈[-90°,90°](k=1,2), the multi-island genetic algorithm provided by the optimization software Isight is used to solve Equation (6). In order to obtain the optimization result faster, the restriction Γ k Take integer, θ k Taking multiples of 10, the optimal design placement track of the composite laminate for tensile strength under uniaxial tensile load conditions obtained by iterative calculation is:

[0086] [<61|0°>]2, the strength of the composite laminate is 18.2kN, and its load-displacement curve is as follows Figure 5 As shown, the strength of the composite laminate [0°] 2 is increased by 13.8% compared with the composite laminate laid in a straight line at a certain angle.

[0087] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to in detail.

[0088] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or replacements to the relevant technical features, and the technical solutions after these changes or replacements will fall within the scope of protection of the present application.

Claims

1. A method for optimizing the laying trajectory of each layer of a composite material laminate with an opening, characterized in that: include: Establish a global coordinate system with the center of the hole in the composite laminate as the origin; With the center of the hole in the composite laminate as the origin, a local coordinate system is constructed. Based on the streamline cluster of the ideal fluid around the cylinder, the placement trajectory of each layer of the composite laminate is defined. Construct the geometric model of the composite laminate, perform finite element meshing, and calculate the coordinates of each finite element mesh in the global coordinate system; Corresponding to each layer of the composite laminate, the coordinates of each finite element grid in the global coordinate system are transformed into the coordinates of the local coordinate system, and the placement tape placement angle corresponding to each finite element grid in the local coordinate system is calculated using the placement tape placement trajectory of each layer of the composite laminate; For each layer of the composite laminate, the placement tape angle corresponding to each finite element grid in the local coordinate system is transformed into the corresponding placement tape angle in the global coordinate system; The laying tape placement angles corresponding to the finite element grids in the global coordinate system for each layer of the composite laminate are assigned to the geometric model, and finite element calculations are performed. Taking the strength of the composite laminate as the optimization target, the laying tape placement trajectories of each layer of the composite laminate are obtained.

2. The method for optimizing the laying trajectory of each layer of a composite material laminate with openings according to claim 1, characterized in that: The local coordinate system is constructed with the center of the opening on the composite laminate as the origin, and the placement trajectory of each layer of the composite laminate is defined based on the streamline cluster of the ideal fluid flow around the cylinder. Specifically, <C k |θ k >,(k=1,2…N); in, <Γ k |θ k > Lay out the laying trajectory parameters for composite laminates; Γ k The control parameters of the stream function of the ideal fluid streamline cluster around the cylinder for the kth layer of the composite laminate with the placement trajectory; θ k is the deflection angle of the local coordinate system of the kth layer of the composite laminate relative to the global coordinate system; N is the number of layers of the composite laminate.

3. The method for optimizing the laying trajectory of each layer of a composite material laminate with openings according to claim 2, characterized in that: The coordinates of each finite element mesh in the global coordinate system are transformed into the coordinates in the local coordinate system corresponding to each layer of the composite laminate, specifically: in, x and y are the coordinates of each finite element mesh in the global coordinate system; x′ k , y′ k are the coordinates of each finite element mesh in the local coordinate system corresponding to the kth layer of the composite laminate.

4. The method for optimizing the laying trajectory of each layer of a composite material laminate with openings according to claim 3, characterized in that: The method corresponds to each layer of the composite laminate and uses the placement tape placement trajectory of each layer of the composite laminate to calculate the placement tape placement angle corresponding to each finite element grid in the local coordinate system, specifically: in, is the placement angle of the lay-up tape corresponding to the kth layer of the composite laminate, for each finite element mesh in the local coordinate system; ψ k The kth layer of the composite laminate is laid with a laying trajectory and the stream function of the streamline cluster of an ideal fluid flowing around a cylinder.

5. The method for optimizing the laying trajectory of each layer of a composite material laminate with openings according to claim 4, characterized in that:

6. The method for optimizing the laying trajectory of each layer of a composite material laminate with openings according to claim 5, characterized in that: The corresponding placement tape placement angles of the finite element grids in the local coordinate system corresponding to each layer of the composite laminate are transformed into corresponding placement tape placement angles in the global coordinate system, specifically: in, is the placement tape angle corresponding to the kth layer of the composite laminate for each finite element mesh in the global coordinate system.

7. The method for optimizing the laying trajectory of each layer of a composite material laminate with openings according to claim 6, characterized in that: The strength of the composite material laminate is taken as the optimization target, and the laying trajectory of each layer of the composite material laminate is obtained, specifically: in, F f is the strength of the composite laminate; Γ min , Γ max The minimum and maximum setting values ​​of the flow function control parameters of the ideal fluid flow streamline cluster around the cylinder for laying the laying trajectory of each layer of the composite laminate; θ min ,θ max The minimum and maximum setting values ​​for the deflection angle of the local coordinate system of each layer of the composite laminate relative to the global coordinate system.

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