Damping optimization and design method of fiber reinforced composite lattice sandwich structure

Abstract

The invention relates to a damping optimization and design method for a fiber-reinforced composite lattice sandwich structure, which belongs to the technical field of vibration reduction and noise reduction of composite lattice sandwich structures. The invention solves the problems of low accuracy of theoretical prediction of the damping performance of composite lattice sandwich structures, and poor optimization effect of geometric parameters based on damping performance. The invention obtains the stress and strain components of each unit of the composite lattice sandwich structure through modal analysis, and solves the modal damping of the structure in combination with the modal strain energy method, thereby providing a set of methods for accurately predicting the damping performance of composite lattice sandwich structures, and can perform structural optimization design based on the damping prediction results, thereby improving the optimization effect, and providing a basis for the design of fiber-reinforced composite lattice sandwich structures with vibration reduction requirements. The method of the invention can be applied to the technical field of vibration reduction and noise reduction of composite lattice sandwich structures.

Description

Technical Field

[0001] The present invention belongs to the technical field of vibration and noise reduction of composite material lattice sandwich structures, and particularly relates to a damping optimization and design method for a fiber reinforced composite material lattice sandwich structure. Background Art

[0002] In recent years, with the rapid development of high-efficiency, high-propulsion ships, the vibration and noise of ship structures have become increasingly prominent. These effects can affect certain aspects of a ship's operational performance, such as reduced concealment and reduced service life due to fatigue. Therefore, it is imperative to find ways to reduce hull vibration to offset these negative effects.

[0003] Composite materials offer numerous advantages, including high specific strength, high specific stiffness, excellent damping performance, designability, and corrosion resistance. They have been widely used in a variety of fields, including aerospace and shipbuilding. Composite sandwich structures are a new type of lightweight structure, consisting of upper and lower panels and a central core. The panels are thin and stiff, while the core is thick and lightweight. Depending on the core topology, sandwich structures can be categorized into lattice, honeycomb, and corrugated types. Research has shown that composite lattice sandwich structures offer superior performance in terms of lightweighting and low-frequency dynamic response. While a number of studies have been conducted domestically and internationally on the damping performance of composite laminates, limited research has focused on the damping performance of composite lattice sandwich structures and the optimization of geometric parameters based on damping performance. Furthermore, theoretical predictions of the damping performance of composite lattice sandwich structures have low accuracy, and optimization of geometric parameters based on damping performance has been ineffective. Therefore, it is crucial to develop an effective, convenient, and highly accurate method for predicting the damping performance of composite lattice sandwich structures and to conduct optimal design. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems of low accuracy of theoretical prediction of the damping performance of composite lattice sandwich structures and poor optimization effect of geometric parameters based on damping performance, and to propose a damping optimization and design method for fiber-reinforced composite lattice sandwich structures.

[0005] The technical solution adopted by the present invention to solve the above technical problems is:

[0006] A damping optimization and design method for a fiber-reinforced composite lattice sandwich structure, the method specifically comprising the following steps:

[0007] Step 1: Use 3D modeling software to create a CAE geometric model of the fiber reinforced composite lattice sandwich structure, and import the created CAE geometric model into Workbench;

[0008] Step 2: After setting the material parameters of the fiber-reinforced composite material in Workbench, set the layup conditions and boundary conditions;

[0009] After meshing the CAE geometric model, modal analysis is performed to obtain the stress and strain components of each unit;

[0010] Step 3: Solve the modal damping of the CAE geometric model based on the stress and strain components obtained in step 2;

[0011] Step 4: Select any parameter of the CAE geometric model as a variable parameter, fix the other parameters of the CAE geometric model, continuously adjust the value of the variable parameter, and repeat steps 1 to 3 to obtain the modal damping corresponding to each value of the variable parameter. Perform curve fitting on the values ​​of the variable parameter and the obtained modal damping, and use the variable parameter value corresponding to the damping extreme value in the curve fitting result as the optimal value of the selected variable parameter;

[0012] Step 5: Select each parameter of the CAE geometric model as a variable parameter in turn, repeat the process of step 4 for each variable parameter, and obtain the optimal value corresponding to each parameter of the CAE geometric model;

[0013] Step 6: Establish an optimized CAE geometric model based on the optimal value corresponding to each parameter of the CAE geometric model, and solve the modal damping of the optimized CAE geometric model to complete the damping optimization.

[0014] Furthermore, the 3D modeling software used to establish the CAE geometric model of the fiber reinforced composite material lattice sandwich structure is SolidWorks.

[0015] Furthermore, in step 2, setting the material parameters of the fiber reinforced composite material in Workbench means setting the panel material parameters in the Orthotropic Elasticity module of Workbench and setting the core member material parameters in the Isotropic Elasticity module of Workbench.

[0016] Furthermore, the specific process of step three is:

[0017]

[0018]

[0019]

[0020] Where K represents the unit number, K = 1, 2, ..., N, N represents the total number of units, p is the component number, p = 1, 2, ..., 6, represents the pth stress component of the Kth element, represents the pth strain component of the Kth element, V K represents the volume of the Kth unit, represents the p-th material specific damping capacity component of the K-th element, and ψ represents the modal damping.

[0021] Furthermore, the parameters of the CAE geometric model include the cross-sectional form of the core layer member, the inclination angle of the core layer member, the number of panel plies and the panel ply angle.

[0022] The beneficial effects of the present invention are:

[0023] The present invention obtains the stress and strain components of each unit of the composite material lattice sandwich structure through modal analysis, and combines the modal strain energy method to solve the modal damping of the structure. It provides a set of methods for accurately predicting the damping performance of the composite material lattice sandwich structure, and can perform structural optimization design based on the damping prediction results, thereby improving the optimization effect, and providing a basis for the design of fiber-reinforced composite material lattice sandwich structures with vibration reduction requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Flowchart for the calculation of stress, strain components and damping of fiber reinforced composite lattice sandwich structures;

[0025] Figure 2 Schematic diagram of a lattice sandwich structure geometric model drawn based on SolidWorks in the embodiment;

[0026] Figure 3 Schematic diagram of modal analysis results obtained based on Workbench in the embodiment;

[0027] Figure 4 This is a diagram of the damping calculation results obtained based on the APDL command stream in the embodiment;

[0028] Figure 5 Graph showing a ply angle-damping fitting curve in an embodiment. DETAILED DESCRIPTION

[0029] Specific implementation method 1. Combination Figure 1 This embodiment describes a damping optimization and design method for a fiber-reinforced composite lattice sandwich structure, the method specifically comprising the following steps:

[0030] Step 1: Use 3D modeling software to create a CAE geometric model of the fiber reinforced composite lattice sandwich structure, and import the created CAE geometric model into Workbench;

[0031] Step 2: After setting the material parameters (referring to the material mechanical properties parameters) of the fiber reinforced composite material in Workbench, set the layup conditions and boundary conditions;

[0032] After meshing the CAE geometric model, modal analysis is performed to obtain the stress and strain components of each unit;

[0033] Step 3: Solve the modal damping of the CAE geometric model based on the stress and strain components obtained in step 2;

[0034] Step 4: Select any parameter of the CAE geometric model as a variable parameter, fix the other parameters of the CAE geometric model, continuously adjust the value of the variable parameter, and repeat steps 1 to 3 to obtain the modal damping corresponding to each value of the variable parameter. Perform curve fitting on the values ​​of the variable parameter and the obtained modal damping, and use the variable parameter value corresponding to the damping extreme value in the curve fitting result as the optimal value of the selected variable parameter;

[0035] In this step, the first-order modal damping, second-order modal damping, third-order modal damping and fourth-order modal damping corresponding to each value of the variable parameter are directly obtained, and a curve fitting is performed on the value of the variable parameter and the obtained fourth-order modal damping;

[0036] Step 5: Select each parameter of the CAE geometric model as a variable parameter in turn, repeat the process of step 4 for each variable parameter, and obtain the optimal value corresponding to each parameter of the CAE geometric model;

[0037] Step 6: Establish an optimized CAE geometric model based on the optimal value corresponding to each parameter of the CAE geometric model, and solve the modal damping of the optimized CAE geometric model to complete the damping optimization.

[0038] The fiber reinforced composite material lattice sandwich structure is designed according to the optimal value corresponding to each parameter of the CAE geometric model, that is, the optimized design of the fiber reinforced composite material lattice sandwich structure is achieved.

[0039] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the 3D modeling software used to establish the CAE geometric model of the fiber reinforced composite material lattice sandwich structure is SolidWorks.

[0040] Other steps and parameters are the same as those in the first embodiment.

[0041] Specific embodiment three: This embodiment differs from specific embodiments one or two in that, in step two, the material parameters of the fiber-reinforced composite material are set in Workbench by setting the panel material parameters in the Orthotropic Elasticity module of Workbench and setting the core layer rod material parameters in the Isotropic Elasticity module of Workbench.

[0042] Other steps and parameters are the same as those in the first or second embodiment.

[0043] Specific embodiment 4: This embodiment differs from any one of specific embodiments 1 to 3 in that the specific process of step 3 is as follows:

[0044]

[0045]

[0046]

[0047] Where K represents the unit number, K = 1, 2, ..., N, N represents the total number of units, p is the component number, p = 1, 2, ..., 6, represents the pth stress component of the Kth element, represents the pth strain component of the Kth element, V K represents the volume of the Kth unit, represents the pth material specific damping capacity component of the Kth element, As a material parameter, it needs to be specified in advance, and ψ represents the modal damping.

[0048] The damping of each modal order is calculated using the method of this embodiment. In this embodiment, p=1,2,…,6, and the definition of pp means: when p=1, only Component, when p=2, only consider Component, when p=3, only consider Component, when p = 4, only consider Component, when p=5, only consider Component, when p=6, only consider component, without considering other components.

[0049] The other steps and parameters are the same as those in the first to third embodiments.

[0050] Specific embodiment five: This embodiment differs from any one of specific embodiments one to four in that the parameters of the CAE geometric model include the cross-sectional form of the core layer member, the inclination angle of the core layer member, the number of panel plies, and the panel ply angle.

[0051] The cross-sectional form of the core member, the inclination angle of the core member, and the number of panel plies are adjusted by redrawing the geometric model in SolidWorks, and the panel ply angle is set and adjusted in the modal analysis module in Workbench.

[0052] The other steps and parameters are the same as those in the first to fourth embodiments.

[0053] Example

[0054] This embodiment uses a certain type of carbon fiber composite panel and a certain aluminum alloy material to perform damping calculation and optimization design. The specific steps are as follows:

[0055] Step 1: Create a point matrix sandwich structure geometry model in SolidWorks, such as Figure 2 As shown, its length is 130 mm, width is 10 mm, total thickness is 6 mm, the core layer unit cell form is Kagome type, the unit cell side length is 5 mm, the rod cross section is a square with a side length of 1 mm, and the inclination angle is 40.6°. The geometric model is imported into Workbench.

[0056] Step 2: Set material parameters. In this example, the panel material is a certain type of carbon fiber composite material, which is considered an orthotropic material and is set using the Orthotropic Elasticity module. The core member is made of a certain type of aluminum alloy material, which is considered an isotropic material and is set using the Isotropic Elasticity module.

[0057] Enter the Modal analysis module and use the local coordinate system to achieve the panel ply effect, set to [0° / 90° / 90° / 0°]. Divide the mesh and ensure that the mesh is fine enough, otherwise the damping calculation results will not converge. Finally, set the boundary conditions to one end fixed and the other end free, and solve. The modal analysis results are as follows: Figure 3 shown.

[0058] Step 3: Add APDL command stream in the Solution section, write the modal damping extraction program, run the solution again, calculate the modal damping of each order, and record it. The damping calculation results are as follows: Figure 4 shown.

[0059] Step 4: In this embodiment, the panel ply is used as a variable, and the middle panel ply angle is adjusted to 75°, 60°, 45°, 30°, 15°, and 0° in sequence. The above steps are repeated to record the modal damping.

[0060] Step 5: Take the middle ply angle as the variable and make a ply angle-damping fitting curve based on the obtained data, such as Figure 5 As shown in , the extreme value is found by taking one of the modal damping as the optimization index.

[0061] Step 6: Optimize all geometric parameters as above and finally obtain the maximum damping value.

[0062] In this embodiment, for a given length, width and thickness, the panel ply adopts [45° / -45° / -45° / 45°], and the rod inclination angle is about 50°. Within the range permitted by the conditional constraints, increasing the cross-sectional area of ​​the rod can obtain better damping performance. The optimal value of the specific damping capacity of this embodiment can reach 8.47%.

[0063] The above examples are merely illustrative of the calculation model and process of the present invention and are not intended to limit the embodiments of the present invention. Persons skilled in the art will readily appreciate that other variations or modifications based on the above description are possible. This list of embodiments is not exhaustive; however, any obvious variations or modifications derived from the technical solution of the present invention remain within the scope of protection of the present invention.

Claims

1. Damping optimization and design method for fiber reinforced composite lattice sandwich structure, characterized by: The method specifically comprises the following steps: Step 1: Use 3D modeling software to create a CAE geometric model of the fiber reinforced composite lattice sandwich structure, and import the created CAE geometric model into Workbench; Step 2: After setting the material parameters of the fiber-reinforced composite material in Workbench, set the layup conditions and boundary conditions; After meshing the CAE geometric model, modal analysis is performed to obtain the stress and strain components of each unit; Step 3: Solve the modal damping of the CAE geometric model based on the stress and strain components obtained in step 2; Step 4: Select any parameter of the CAE geometric model as a variable parameter, fix the other parameters of the CAE geometric model, continuously adjust the value of the variable parameter, and repeat steps 1 to 3 to obtain the modal damping corresponding to each value of the variable parameter. Perform curve fitting on the values ​​of the variable parameter and the obtained modal damping, and use the variable parameter value corresponding to the damping extreme value in the curve fitting result as the optimal value of the selected variable parameter; Step 5: Select each parameter of the CAE geometric model as a variable parameter in turn, repeat the process of step 4 for each variable parameter, and obtain the optimal value corresponding to each parameter of the CAE geometric model; The parameters of the CAE geometric model include the cross-sectional form of the core member, the inclination angle of the core member, the number of face sheet layers, and the face sheet layer angle; Step 6: Establish an optimized CAE geometric model based on the optimal value corresponding to each parameter of the CAE geometric model, and solve the modal damping of the optimized CAE geometric model to complete the damping optimization.

2. The damping optimization and design method of a fiber reinforced composite lattice sandwich structure according to claim 1, characterized in that: The 3D modeling software used to establish the CAE geometric model of the fiber reinforced composite material lattice sandwich structure is SolidWorks.

3. The damping optimization and design method of a fiber reinforced composite lattice sandwich structure according to claim 2, characterized in that: In the step 2, the material parameters of the fiber reinforced composite material are set in Workbench, which is to set the panel material parameters in the Orthotropic Elasticity module of Workbench and to set the core member material parameters in the Isotropic Elasticity module of Workbench.

4. The damping optimization and design method of a fiber reinforced composite lattice sandwich structure according to claim 3, characterized in that: The specific process of step three is: in, Indicates the unit number, , Indicates the total number of units, is the component number, , Indicates the Unit No. stress components, Indicates the Unit No. strain components, Indicates the The volume of a unit, Indicates the Unit No. The specific damping capacity component of each material, represents modal damping.

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