Fluid-structure interaction refined modeling and modal analysis method for tensioned film structure

Abstract

The invention discloses a fluid-structure interaction refined modeling and modal analysis method for a tensioned film structure. A high-precision finite element unit is selected to simulate a thin film and an air domain, the mutual coupling effect of the thin film and air is achieved through the fluid-solid coupling technology, the initial prestress state of the thin film under the action of the tensioning force of the inhaul cable is obtained through nonlinear static analysis, and the natural vibration frequency and the vibration mode of the tensioned thin film structure are obtained through a linear perturbation mode analysis method. The method has the following advantages that efficient modeling is achieved through parameterization, and the modeling period is remarkably shortened; on the premise of considering geometric nonlinearity and a fluid-solid coupling effect, the dynamic behavior of coupling of a thin film structure and air is accurately captured; the method can be applied to the fields of spaceflight and constructional engineering, and optimization design and vibration control of a thin film structure are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical fields of aerospace engineering and computational mechanics, and particularly to a refined dynamic modeling method for fluid-structure interaction of a tensioned membrane structure. Background Art

[0002] Due to characteristics such as light weight, flexibility, and easy formability, membrane structures are widely used in engineering fields such as inflatable structures and tension structures. However, the dynamic characteristics of membrane structures not only depend on the geometric characteristics and material properties of the membrane itself, but are also strongly affected by the initial prestress state, the additional mass of the surrounding air, the damping effect, and the fluid-structure interaction characteristics. Traditional modal analysis methods fail to comprehensively consider the combined effects of the above various factors on the natural vibration frequency and vibration mode of membrane structures, and it is difficult to accurately reflect their dynamic characteristics. Based on this, the present invention proposes a fluid-structure interaction modeling and modal analysis method for tensioned membrane structures that combines nonlinear static analysis and linear perturbation modal analysis methods, providing a scientific and efficient solution for the analysis of the dynamic characteristics of membrane structures. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the present invention provides a refined dynamic modeling method for fluid-structure interaction of a tensioned membrane structure, which solves the problem that traditional modal analysis methods do not consider the initial prestress state, geometric nonlinearity, and fluid-structure interaction effects (such as fluid additional mass and damping effects), resulting in the inability to accurately reflect the true dynamic response of membrane structures with large deformations.

[0004] To achieve the above objectives, the present invention is realized through the following technical solutions: A refined dynamic modeling method for fluid-structure interaction of a tensioned membrane structure, comprising the following steps:

[0005] Step 1, define parameterized data, including the geometric parameters and physical parameters of the model;

[0006] Step 2, select the element type;

[0007] Step 3, establish the geometric model of the planar membrane structure and the cable;

[0008] Step 4, establish the geometric model of the air structure;

[0009] Step 5, set the number of divided elements and element attributes, and perform element division on the lines representing the membrane structure, the cable, and the air respectively;

[0010] Step 6, define the contact interface between the membrane structure and the air;

[0011] Step 7, couple the degrees of freedom of the membrane structure and the air; couple the degrees of freedom of the air and the air;

[0012] Step 8, apply initial strain to the cable;

[0013] Step 9, perform a non-linear static solution for the entire model;

[0014] Step 10, perform a modal solution for the thin film by the linear perturbation modal analysis method;

[0015] Step 11, reset the constraint conditions for the thin film structure, and enter the post-processing to read the modal results;

[0016] Step 12, read the APDL modeling command stream file through ANSYS software to realize the parametric modeling of the finite element model for the fluid-structure interaction non-linear dynamic modeling of the tensile membrane structure;

[0017] Preferably, step S1 includes: in the / PREP7 pre-processing module of the ANSYS APDL modeling language software, define the geometric parameters and physical parameters of the model. The geometric parameters include: the size of the thin film structure, the size of the air domain, and the size of the cable. The physical parameters include: the density, elastic modulus, Poisson's ratio of the thin film material and the cable material, the density of the air material, and the sound speed coefficient

[0018] Preferably, step S2 includes: using a shell element (SHELL281 element) to simulate the thin film structure, using a fluid element (FLUID220 element) to simulate the air domain, and using a rod element (LINK180 element) to simulate the cable;

[0019] Preferably, step S3 includes: establish key points according to the size of the thin film, establish lines through the key points, and finally establish surfaces according to the lines to establish a closed square thin film geometric model. At the same time, establish cable key points at the corresponding positions, and establish lines through the key points to establish the cable geometric model.

[0020] Preferably, step S4 includes: establish geometric models of air on both sides of the thin film. The length and width of the air should be greater than the size of the thin film. The thickness of the air on one side of the thin film should be greater than half of the wavelength of the first-order vibration mode of the thin film. The nodes where the air model contacts the thin film structure need to coincide with the nodes on the surface of the thin film structure established in step 3.

[0021] Preferably, in step S5, for the lines constituting the thin film structure, the cable, and the air, respectively set the number of divided elements and the element attributes to perform mesh division. And at the contact interface between the thin film and the air, the number of divided elements of the thin film and the number of divided elements of the air need to be kept consistent, so as to ensure that after the mesh division of the thin film structure and the air model, the nodes at the contact interfaces between the thin film and the air, and between the air and the air coincide.

[0022] Preferably, in step S6: use the "SF" command to set the fluid-structure interaction interface for the front and back sides of the square thin film using the "FSI" command.

[0023] Preferably, in step S7: Select all the nodes where the thin film structure contacts with the air and the air contacts with the air, couple them through the "CPINTF" command, and couple the degrees of freedom of the nodes where the thin film coincides with the air and the nodes where the air coincides on both sides of the thin film.

[0024] Preferably, in step S8: Apply initial strain to the cable element to provide initial pre-tension for the thin film structure.

[0025] Preferably, in step S9: Conduct a non-linear static analysis on the established fluid-structure interaction finite element model of the thin film.

[0026] Preferably, in step S10: Use the linear perturbation modal analysis method to conduct modal analysis and read the modal results through post-processing.

[0027] The present invention provides a refined dynamic modeling method for the fluid-structure interaction of a tensioned thin film structure. It has the following beneficial effects:

[0028] 1. The present invention uses the SHELL281 element to model the thin film. This element can accurately simulate the stretching, bending and large deformation behaviors of the thin film, significantly improving the calculation accuracy of the thin film structure. Through geometric non-linear analysis (activate the NLGEOM, ON command), the non-linear deformation characteristics of the thin film in the high-tension state are completely captured, solving the problem of large calculation deviation caused by ignoring non-linear effects in traditional methods. The FLUID220 element is used to simulate the air domain. Combining the parametric definition of the sound speed and density, through the node coupling treatment of the fluid-structure interface (FSI), an accurate description of the dynamic interaction between the thin film and the fluid is realized. Compared with the simple hydrostatic model, this method is more suitable for the analysis of thin films in complex dynamic environments, such as the air resistance and added mass effects under high-speed movement or vibration conditions.

[0029] 2. The present invention defines the degree-of-freedom coupling interface between the thin film and the air through the "SF" and "CPINTF" commands, ensuring a one-to-one correspondence of the interface nodes between the thin film and the air domain. This coupling treatment improves the accuracy of the fluid-structure interface calculation and provides a solid foundation for the simulation of the fluid-structure dynamic coupling behavior of the thin film.

[0030] 3. Through static analysis and superposition modal analysis, the linear perturbation modal analysis method uses the non-linear static analysis results as the initial conditions and conducts modal analysis by introducing the initial stress field, which can accurately reflect the true dynamic characteristics of the thin film under the tension state. Especially in the large-deformation thin film structure, the initial prestress has a significant impact on the modal characteristics, and the linear perturbation modal analysis method can capture this prestress effect, thus avoiding the modal frequency deviation caused by neglecting the stress effect in the traditional method. At the same time, in the fluid-structure interaction system, due to the hydrodynamic effect introducing an asymmetric stiffness matrix, the traditional symmetric modal analysis method cannot be directly applied. The linear perturbation modal analysis method can effectively solve this problem through small perturbation calculations based on the initial state, providing a general method for the modal analysis of complex fluid-structure interaction systems. The accuracy of the linear perturbation modal analysis method is based on the static solution and can accurately reflect the dynamic characteristics of the thin film structure under complex working conditions. In addition, this method is applicable to various boundary conditions and loading situations and has strong adaptability. Description of the Drawings

[0031] Figure 1 It is the flowchart of parametric modeling of the finite element model of the tensioned thin film structure under the fluid-structure interaction effect in the present invention;

[0032] Figure 2 It is the schematic diagram of the TXT text in the command flow format for defining the thin film and air elements in ANSYS APDL language in the present invention;

[0033] Figure 3 It is the schematic diagram of the geometric model of the cable-supported thin film structure established in the present invention;

[0034] Figure 4 It is the schematic diagram of the geometric model of the air domain established in the present invention;

[0035] Figure 5 It is the schematic diagram of the finite element model after coupling the cable-supported thin film structure and the air domain in the present invention;

[0036] Figure 6 It is the schematic diagram of the TXT text in the command flow format for defining the coupling interface in ANSYS APDL language in the present invention;

[0037] Figure 7 It is the schematic diagram of the TXT text in the command flow format for defining the coupling of the thin film structure and air in ANSYS APDL language in the present invention;

[0038] Figure 8 It is the schematic diagram of the first four vibration modes after fluid-structure interaction of the overall model in the present invention;

[0039] Figure 9Schematic diagram of the TXT text in the form of a command stream for solving modal analysis using the linear perturbation modal analysis method defined in ANSYS APDL language in the present invention; Detailed implementation manners

[0040] Next, in combination with the accompanying drawings of the specification of the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0041] Please refer to the attached Figure 1 - attached Figure 9 The embodiment of the present invention provides a refined dynamic modeling method for fluid-structure interaction of a tensioned membrane structure. First, in the preprocessing stage, the geometric parameters and physical parameters of the model are defined. Then, the element type is determined, the material property parameters are defined, and the real constants of the elements are defined. Next, all the key points included in the square membrane are established, and the lines are generated by connecting the key points. Next, the number of divided elements and the element attributes are set respectively, and the element division is carried out on the membrane structure, the cable, and the air part respectively. The nodes where the membrane and the contact surface coincide are processed to make the membrane and the air completely coincide. Next, initial strain is applied to the cable to provide initial prestress for the membrane. Subsequently, the fluid-structure coupling interface is set for fluid-structure node coupling. Finally, the APDL modeling command stream file is read by ANSYS software to realize the parametric modeling of the refined finite element model of the fluid-structure interaction of the tensioned membrane structure.

[0042] The method of the present invention specifically includes the following steps:

[0043] Step 1, define the geometric parameters and physical parameters of the model.

[0044] Further, Step 1 includes: in the / PREP7 preprocessing module, define the geometric parameters and physical parameters of the model. The geometric parameters include: the length, width, and thickness of the membrane structure, the length, width, and thickness of the air domain, and the diameter of the cable. Among them, the thickness of the SHELL281 element and the diameter of the cable are both defined through the "SECTYPE" command and the "SECDATA" command. The physical parameters include: the density, elastic modulus, Poisson's ratio, and thermal expansion coefficient of the membrane material; the fluid density and sound speed; the density, elastic modulus, Poisson's ratio, etc. of the cable, which are defined through the "MP" command.

[0045] Step 2, determine the element type and define the material property parameters.

[0046] Step 2 includes: determining the element type through the "ET" command. The SHELL281 element is used to simulate the thin film structure, the FLUID220 element is used to simulate the air around the thin film, and the LINK180 element is used to simulate the cable.

[0047] Step 3: Establish the geometric models of the thin film structure and the cable;

[0048] Furthermore, Step 3 includes: defining the corner points of the thin film as key points using the "K" command, and defining the key points of the cable at the corresponding positions.

[0049] Furthermore, generate lines by connecting the key points using the "L" command. Connect the above key points in sequence to obtain the boundary lines of the four sides of the thin film and the geometric lines of the cable.

[0050] Furthermore, generate surfaces by using the "AL" command for all the line segments that make up the four sides of the thin film.

[0051] Step 4: Establish the geometric model of the air structure.

[0052] Furthermore, Step 5 includes: establishing key points on both sides of the thin film using the "K" command.

[0053] Furthermore, generate the geometric model of the air around the thin film using the "L" command and the "V" command.

[0054] Step 5: Set the number of divided elements and element attributes, and perform element division on the lines representing the thin film structure, the cable, and the air respectively;

[0055] Step 6 includes: respectively selecting the lines representing the thin film, the cable, and the fluid using the "LSEL" command, then setting the number of elements and element attributes of the thin film and the fluid using the "LESIZE", "AATT", and "VATT" commands respectively, then using the "MSHAPE" command to determine the element shape of the mesh; finally, using the "MSHKEY" command to determine the type of mesh division to complete the mesh division. Among them, at the contact surface between the thin film and the fluid, the number of elements divided on the thin film surface and the number of elements divided on the fluid need to be consistent, that is, ensure that after the mesh division of the thin film model and the fluid model, the nodes at their contact interface coincide.

[0056] Step 7: Define the contact interface between the thin film structure and the air.

[0057] Step 7 includes: selecting all the nodes where the thin film structure contacts the air and the air contacts the air, and defining the fluid-structure interaction interface through the "SF" command.

[0058] Furthermore, for the contact surface between the fluid model and the thin film model, use the "ASEL" command to select the surface of the liquid model, then use the "NSLA" command to select the nodes on these surfaces, and use the "FSI" command in the "SF" command for the nodes on these surfaces to set these surfaces as the contact interfaces in contact with the solid phase.

[0059] Step 8: Couple the degrees of freedom of the contact interface.

[0060] Furthermore, Step 8 includes: using the "ASEL" command to select the surface of the liquid model. By using the aforementioned modeling method, the nodes on these surfaces coincide. So, then use the "NSLA" command to select the nodes on these surfaces together, and use the "CPINTF" command for the nodes on both types of surfaces to perform node coupling, thereby establishing a coupled model with the air-fluid-solid coupling effect.

[0061] Step 9: Apply initial strain to the cable.

[0062] Step 9 includes: using the "ESEL" command to select the cable element, and then using the "INISTATE" command to apply initial strain to the cable element to provide initial prestress for the thin film element.

[0063] Step 10: Perform a non-linear static solution.

[0064] Step 10 includes: activating the large deformation option through the "NLGEOM, ON" command, and then using the "NROPT, UNSYM" command to solve the non-linear static solution for the structure by the asymmetric method.

[0065] Step 11: Perform modal solution for the thin film by the linear perturbation modal analysis method, and read the frequency and vibration mode of the thin film structure through post-processing.

[0066] Step 11 includes: using the "PERTURB, MODAL,,,PARKEEP" command to perform modal solution for the structure by the linear perturbation modal analysis method, and the "MODOPT, UNSYM" command to perform analysis by the asymmetric method. After the analysis is completed, enter the post-processing through / post1, select the thin film element, and display its frequency and vibration mode results.

[0067] Applying the modeling method from Step 1 to Step 11 to the field of fluid-solid coupling dynamics of the tensioned membrane structure can construct a finite element model that can accurately reflect the coupled vibration characteristics of the membrane and the surrounding air environment. Through the dynamic analysis of this model, the natural frequency and vibration mode of the membrane in the real coupled environment can be accurately obtained, providing a more practical theoretical basis and analysis results for studying the dynamic behavior of the membrane structure.

[0068] Example 1:

[0069] As Figure 1 shown, Embodiment 1 provides a refined dynamic modeling method for fluid-structure interaction of a tensile membrane structure, including the following steps:

[0070] Step 1: Define the geometric parameters and physical parameters of the model, define the material property parameters, and define the element real constants.

[0071] Enter the preprocessing module, and define the geometric parameters and physical parameters of the material properties of the model through the "MP" command. The geometric parameters include: the length, width, and thickness of the membrane; the length, width, and thickness of the air body; the diameter of the cable. The physical parameters include: the density, elastic modulus, Poisson's ratio, and thermal expansion coefficient of the membrane material, the density and sound speed of the air body, and the density, elastic modulus, and Poisson's ratio of the cable.

[0072] Among them, the defined geometric parameters and physical parameters are as follows:

[0073] The length of the membrane is 1.0 m, the width is 1.0 m, and the thickness is 0.1 mm; the length of the air body is 1.4 m, the width is 1.4 m, and the thickness is 2.4 m, and the diameter of the cable is 4 mm.

[0074] The density ρ of the SHELL281 element is 1450 kg / m3, the elastic modulus is E = 3 GPa, and the Poisson's ratio is 0.34;

[0075] The density of the FLUID220 element: ρ = 1.23 kg / m3; the speed of sound propagation in this material is v = 343 m / s.

[0076] The density ρ of the LINK180 element is 756 kg / m3, the elastic modulus is E = 1.07 MPa, and the Poisson's ratio is 0.3;

[0077] Furthermore, for the thickness of the SHELL281 element and the diameter of the LINK180 element, first determine the membrane element number and element type through the "SECTYPE" command, and then use the "SECDATA" command to define the thickness of the membrane element and the diameter of the cable element.

[0078] Step 2: Determine the element type.

[0079] When determining the element type, as Figure 2 shown, establish the element command stream.

[0080] The thin film and fluid element types are established through the "ET" command. The SHELL281 element is used to simulate the thin film structure; the FLUID220 element is used to simulate the air around the thin film. By setting KEYOPT(6) of the FLUID220 element to 1, it means that the sound speed is equivalent to an incompressible fluid approaching infinity, that is, the liquid is determined to be an incompressible fluid; the LINK180 element is used to simulate the cable structure.

[0081] Step 3: Establish the geometric model of the thin film structure.

[0082] Furthermore, step 3 includes: defining the corner points around the thin film as key points and defining the key points of the cables at the corresponding positions by using the "K" command.

[0083] Furthermore, lines are generated by connecting the key points through the "L" command. Connect the above key points in sequence to obtain the boundary lines of the four sides of the thin film and the structural lines of the cables.

[0084] Furthermore, all the line segments forming the four sides of the thin film are used to generate a surface through the "AL" command.

[0085] Step 5: Establish the geometric model of the air structure.

[0086] Furthermore, step 5 includes: establishing key points on both sides of the thin film through the "K" command.

[0087] Furthermore, the geometric model of the air around the thin film is generated through the "L" command and the "V" command.

[0088] Step 6: Set the number of divided elements and element attributes, and perform element division on the lines representing the thin film structure, cables, and air respectively.

[0089] Furthermore, by using the "LSEL" command to select the lines representing the thin film, cables, and fluid respectively, and using the "LESIZE" and "LATT" commands to set the number of divided elements and assign the element attributes to the model lines respectively, then using the "MSHAPE" command to determine the element shape of the mesh; finally, using the "MSHKEY" command to determine the type of mesh division to complete the mesh division. Among them, at the contact surface between the thin film and the fluid, the number of elements divided on the thin film surface and the number of elements divided on the fluid need to be kept consistent, that is, to ensure that after the mesh division of the thin film model and the fluid model, the nodes at their contact interface coincide.

[0090] Step 7: Define the contact interface between the thin film structure and the air.

[0091] Furthermore, the command stream for defining the coupling interface is as Figure 3As shown below. The specific method is as follows: Step 1: Select face No. 2 from all faces through the command "ASEL, s,,, 2". "nsel, r, loc, x, 0, 1" means to select the nodes included in the x-axis in the current coordinate system, and the selected range of the x-axis coordinate is from 0 to 1. Step 2: "nsel, r, loc, y, 0, 1" means to select the nodes included in the y-axis in the current coordinate system, and the selected range of the y-axis coordinate is from 0 to 1. Step 3: Define the above-selected nodes as a coupled interface through the command "SF, ALL, FSI". In the same way, define the face where the air on the back side of the thin film contacts the thin film, i.e., face No. 8, as a coupled interface.

[0092] Step 8: Couple the degrees of freedom of the contact surfaces.

[0093] The command flow for defining the coupled interface is as Figure 3 shown below. The specific method is as follows: Use the "ASEL" command to select the faces of the liquid model. By using the aforementioned modeling method, the nodes on these faces coincide. Then use the "NSLA" command to select all the nodes on the thin film and the nodes within the size range of the thin film on the face in contact with the thin film. Use the command "CPINTF, ALL" to couple the degrees of freedom of the nodes on the face. Then use the same method to couple the degrees of freedom of the nodes where the air outside the size of the thin film coincides with the air. The final coupled overall model is shown in the figure.

[0094] Step 9: Apply initial strain to the cable.

[0095] Use the "ESEL" command to select the cable elements, and then apply initial strain to the cable elements through the "INISTATE" command to provide initial prestress for the thin film elements.

[0096] Step 10: Perform a non-linear static solution for the model.

[0097] Furthermore, perform a non-linear static solution for the entire model. The specific implementation method is as follows: Step 1: Select the static analysis method through the command "ANTYPE, STATIC", and then activate the large deformation option through the command "NLGEOM, ON". Step 2: Select the asymmetric method to perform modal analysis through the command "NROPT, UNSYM".

[0098] Step 11: Perform modal solution for the thin film through the linear perturbation modal analysis method.

[0099] The command flow for performing modal solution for the thin film through the linear perturbation modal analysis method is as Figure 9As shown below. The specific implementation method is as follows: Use the "PERTURB, MODAL,,, PARKEEP" command to perform modal solution for the structure by linear perturbation modal analysis method, and use the "QRDOPT, ON" and "MODOPT, UNSYM" commands to perform analysis by the asymmetric method.

[0100] Finally, enter the post-processing stage, process the solution results based on the ANSYS APDL language, obtain the frequencies of the thin film structure in the form of a list, and obtain the first, second, and third order modal vibration mode diagrams as Figure 8 shown.

[0101] Although the embodiments of the present invention have been described, for those of ordinary skill in the art, it can be understood that various modifications, changes, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

[0102] Beneficial effects of Embodiment 1: In this embodiment, through the combination of the fluid-structure interaction modeling method of ANSYS APDL, nonlinear static solution, and linear perturbation modal analysis method, a fine dynamic modeling of the tensile membrane structure is realized. By applying initial strain to the cable to introduce the initial prestress of the membrane, node coupling of the fluid interface (CPINTF command), and activation of geometric nonlinear effects (NLGEOM command), the accuracy of modal analysis is significantly improved, and the defects of traditional methods that ignore initial stress and fluid added mass are solved. The experimental results (the first 3 order modal vibration modes) verify that the model can accurately capture the membrane-air coupling vibration characteristics and provide a reliable tool for the dynamic design of the membrane structure.

[0103] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A refined dynamic modeling method for fluid-structure interaction of tensile membrane structures, characterized in that, A three-dimensional finite element model of a tensioned membrane structure with fluid-structure interaction characteristics is established by a parametric modeling method, which specifically includes the following steps: Step 1, define parametric data, including the geometric parameters and physical parameters of the model; Step 2, select the element type; Step 3, establish the geometric model of the planar membrane structure and the cable; Step 4, establish the geometric model of the air structure; Step 5, set the number of divided elements and element attributes, and perform element division on the lines representing the membrane structure, the cable, and the air respectively; Step 6, define the contact interface between the membrane structure and the air; Step 7, couple the degrees of freedom of the membrane structure and the air; couple the degrees of freedom of the air and the air; Step 8, apply initial strain to the cable; Step 9, perform a nonlinear static solution on the entire model; Step 10, perform a modal solution on the membrane by the linear perturbation modal analysis method; Step 11, reset the constraint conditions for the membrane structure, and enter the post-processing to read the modal results; Step 12, read the APDL modeling command stream file through ANSYS software to realize the parametric modeling of the finite element model for the fluid-structure interaction nonlinear dynamics modeling of the tensioned membrane structure.

2. The refined dynamic modeling method for fluid-structure interaction of a tensile membrane structure according to claim 1, wherein The said step S1 includes: in the / PREP7 preprocessing module of the ANSYS APDL modeling language software, define the geometric parameters and physical parameters of the model. The geometric parameters include: the size of the membrane structure, the size of the air domain, and the size of the cable; the physical parameters include: the density, elastic modulus, Poisson's ratio of the membrane material and the cable material, the density of the air material, and the sound speed coefficient.

3. A refined dynamic modeling method for fluid-structure interaction of a tensile membrane structure according to claim 1, characterized in that, The said step S2 includes: use the shell element (SHELL281 element) to simulate the membrane structure, use the fluid element (FLUID220 element) to simulate the air domain, and use the rod element (LINK180 element) to simulate the cable.

4. A refined dynamic modeling method for fluid-structure interaction of a tensile membrane structure according to claim 1, characterized in that The said step S3 includes: establish key points according to the membrane size, establish lines through the key points, and finally establish surfaces according to the lines to establish a closed square membrane geometric model. At the same time, establish cable key points at the corresponding positions, and establish lines through the key points to establish the cable geometric model.

5. A refined dynamic modeling method for fluid-structure interaction of a tensile membrane structure according to claim 1, characterized in that The said step S4 includes: establish the geometric models of the air on both sides of the membrane respectively. The length and width of the air should be greater than the membrane size. The thickness of the air on one side of the membrane should be greater than half of the first-order vibration mode wavelength of the membrane. The nodes of the air model in contact with the membrane structure need to coincide with the nodes on the surface of the membrane structure established in step 3.

6. A refined dynamic modeling method for fluid-structure interaction of a tensile membrane structure according to claim 1, characterized in that, The said step S5 includes: for the lines constituting the membrane structure, the cable, and the air, set the number of divided elements and element attributes respectively, so as to perform mesh division. And at the contact interface between the membrane and the air, the number of divided elements of the membrane and the number of divided elements of the air need to be kept consistent, so as to ensure that after the mesh division of the membrane structure and the air model, the nodes at the contact interfaces between the membrane and the air, and the air and the air coincide.

7. A refined dynamic modeling method for fluid-structure interaction of a tensile membrane structure according to claim 1, characterized in that In the said step S6: use the "SF" command to set the fluid-structure coupling interface for the front and back sides of the square membrane using the "FSI" command.

8. A refined dynamic modeling method for fluid-structure interaction of a tensile membrane structure according to claim 1, characterized in that, In the step S7: Select all the nodes where the thin film structure contacts with the air and the air contacts with the air, couple them through the "CPINTF" command, and couple the degrees of freedom of the nodes where the thin film coincides with the air and the nodes where the air coincides on both the front and back sides of the thin film.

9. A refined dynamic modeling method for fluid-structure interaction of a tensioned membrane structure according to claim 1, characterized in that, In the step S8: Apply an initial strain to the cable element to provide an initial pre-tension for the thin film structure.

10. A refined dynamic modeling method for fluid-structure interaction of a tensile membrane structure according to claim 1, characterized in that In the step S9: Conduct a non-linear static analysis on the established fluid-structure interaction finite element model of the thin film.

11. A refined dynamic modeling method for fluid-structure interaction of a tensile membrane structure according to claim 1, characterized in that, In the step S10: Use the linear perturbation modal analysis method to conduct a modal analysis and read the modal results through post-processing.

Images