Titanium matrix composite landing gear shock absorber fluid-structure coupling and modeling method
By using fluid-structure interaction modeling, the fluid-structure interaction of aircraft landing gear buffers is accurately simulated, solving the problems of insufficient simulation accuracy and incomplete material property characterization in existing technologies, and realizing high-precision buffer performance evaluation and optimization design.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHENYANG AIRCRAFT DESIGN INST AVIATION IND CORP OF CHINA
- Filing Date
- 2026-04-17
- Publication Date
- 2026-07-14
AI Technical Summary
Existing technologies struggle to accurately characterize internal fluid-structure interactions and material properties when simulating aircraft landing gear buffers, resulting in insufficient simulation accuracy and incomplete material property characterization, which affects the accuracy and safety of buffer design.
A fluid-structure interaction (FSI) modeling method combining the finite element method and the finite volume method was used to establish the structural and fluid models of the titanium-based composite landing gear buffer. A bidirectional coupled simulation was achieved through a FSI solver to accurately capture the interaction between the oil and the titanium-based composite structure. The ADINA-Structure, ADINA-CFD, and ADINA-FSI modules in the ADINA software were used for model integration and solution.
It significantly improves the accuracy of predicting the dynamic response of the buffer, truly reflects the stress and strain distribution of key components, with an error of less than 5%, and provides a high-fidelity simulation basis for buffer performance evaluation and optimization design.
Smart Images
Figure CN122389447A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of aerospace technology, and in particular relates to a fluid-structure interaction and modeling method for titanium-based composite landing gear buffers. Background Technology
[0002] In the design and analysis of landing gear buffers in the aerospace industry, accurately calculating their buffering characteristics, especially damping characteristics, is crucial for ensuring safe aircraft landings. Currently, engineering approaches mainly rely on two types of techniques. One type is engineering algorithms based on multibody dynamics, which are typically used for the overall motion analysis of landing gear. However, for buffers with complex internal structures, their simulation accuracy is limited, making it difficult to capture the details of internal fluid-structure interactions. The other type is based on computational fluid dynamics, which, while theoretically providing more accurate simulations of fluid behavior, consumes enormous computational resources and is too costly, making it difficult to widely apply this method in practical engineering for iterative analysis and optimization design of the entire landing gear buffer performance.
[0003] These existing technologies have clear technical shortcomings in practical applications. First, there is the problem of insufficient simulation accuracy. Traditional methods, including simplified theoretical models or one-way coupled simulations, struggle to accurately characterize the complex two-way interaction between the internal fluid and solid structure of the buffer under severe impact loads. For example, at the moment of aircraft landing, the force of the high-pressure fluid on the buffer cylinder wall causes minute deformations in the structure, which in turn alters the flow field morphology and pressure distribution, thus affecting the damping force. Traditional simulations often ignore this real-time feedback effect or oversimplify, leading to deviations in the prediction of the buffer's dynamic response, such as the buffer force curve, directly impacting the accuracy of its energy absorption characteristics assessment. Second, there is the problem of incomplete material property characterization. With the application of advanced materials such as titanium-based composites in buffers, their anisotropic and other nonlinear mechanical behaviors have become significant. However, existing models often fail to fully characterize these properties and cannot accurately reflect the stress-strain distribution of such material components under extreme high-pressure conditions. This poses a potential risk to the structural strength design of the buffer, potentially leading to conservative or insufficient design. The difficulty in solving these problems lies in establishing an effective method that can simulate the bidirectional coupling mechanism between complex fluids and nonlinear solid materials with high fidelity, while ensuring computational efficiency and feasibility. Summary of the Invention
[0004] To address the aforementioned technical issues, this invention proposes a fluid-structure interaction and modeling method for titanium-based composite landing gear buffers. This method enables high-precision simulation of the fluid-structure interaction effect of the buffer under impact loads. The simulation results are in high agreement with physical experiments, with an error of less than 5%, and can be used for buffer performance evaluation and optimization design.
[0005] To achieve the above objectives, this invention provides a method for fluid-structure interaction and modeling of titanium-based composite landing gear buffers, comprising: A structural model of the buffer is established in the Lagrangian coordinate system based on the finite element method. A fluid model of the oil inside the buffer is established in the ALE coordinate system based on the finite volume method. Set loads and boundary conditions, including fixing the outer cylinder of the buffer, applying a displacement-time curve to the piston rod end to simulate landing impact, and defining the fluid-structure interaction interface; The structural model and the fluid model are integrated in the fluid-structure interaction solver; Performing fluid-structure interaction (FSI) solutions, which includes: S1. At the fluid-structure interaction interface, the pressure data calculated by the fluid model is transmitted to the structural model; S2. The displacement and velocity data calculated by the structural model are passed to the fluid model as moving boundary conditions; S3. Repeat S1 and S2 iteratively until the convergence criterion is met; Extract the dynamic response parameters of the buffer, including the buffer force-displacement curve.
[0006] Optionally, the process of establishing the structural model of the buffer includes: In the ADINA-Structure module, a geometric model including the outer cylinder, piston rod, and support structure is established based on the actual three-dimensional geometric dimensions of the buffer. Assign the material properties of titanium-based composite materials to the geometric model; The geometric model is meshed using finite element methods, solid element types are selected, and the mesh is refined for stress concentration areas.
[0007] Optionally, the process of establishing a fluid model of the oil inside the buffer includes: In the ADINA-CFD module, a geometric model of the fluid domain is established based on the actual geometry of the internal chamber of the buffer. The fluid domain includes the main oil chamber, the throttle valve and its connecting flow channel, the oil circulation channel, and the piston movement clearance area. To impart material properties to the fluid domain; Select the Navier-Stokes equations as the governing equations and enable the weakly compressible flow option.
[0008] Optionally, the process of setting loads and boundary conditions includes: Set the mounting end of the buffer outer cylinder as a fixed constraint; A displacement-time curve obtained by fitting drop test data is applied to the piston rod end; The surfaces of the piston rod, piston head, and inner wall of the cylinder that come into contact with the oil are defined as fluid-structure interaction interfaces.
[0009] Optionally, the process of integrating the structural model and the fluid model in the fluid-structure interaction solver is performed in the ADINA-FSI module; The fluid-structure interaction interface includes the piston rod surface, the piston head end face, and the inner wall of the cylinder.
[0010] Optionally, the process of performing fluid-structure interaction (FSI) solutions may also include using an implicit time integration algorithm. Combined with a strongly coupled solution strategy; Set adaptive time step; The convergence tolerances for force and displacement are set as convergence criteria.
[0011] Optionally, the process of extracting the dynamic response parameters of the buffer includes: Obtain structural responses, including displacement-time curves, velocity-time curves, and acceleration-time curves of the piston rod, as well as stress distribution cloud maps and strain distribution cloud maps of key components; Obtain the flow field response, including pressure distribution cloud map, flow velocity vector map, and pressure-time curves at key locations within the oil cavity; Obtain the buffer force-displacement curve.
[0012] Optionally, the titanium-based composite material has orthogonal anisotropic properties.
[0013] Technical advantages of this invention: This invention discloses a fluid-structure interaction (FSI) and modeling method for titanium-based composite landing gear buffers. By establishing a two-way FSI model, it can accurately capture the complex interaction between the internal oil and the titanium-based composite material structure of the buffer under impact loads, significantly improving the accuracy of dynamic response prediction. This method improves the characterization of the nonlinear mechanical behavior of titanium-based composite materials and can realistically reflect the stress-strain distribution of key components under high pressure. Ultimately, it effectively solves the problems of insufficient simulation accuracy and incomplete material property characterization in traditional methods, providing a high-fidelity simulation basis for buffer performance evaluation and structural optimization design. Attached Figure Description
[0014] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a flowchart illustrating a method for fluid-structure interaction and modeling of a titanium-based composite landing gear buffer according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the fluid domain geometric model according to an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the load and boundary condition settings in an embodiment of the present invention; Figure 4 This is a schematic diagram of the buffer force-displacement curve in an embodiment of the present invention. Detailed Implementation
[0015] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.
[0016] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.
[0017] like Figure 1 As shown, this embodiment provides a method for fluid-structure interaction and modeling of titanium-based composite landing gear buffers, including: A structural model of the buffer is established in the Lagrangian coordinate system based on the finite element method. A fluid model of the oil inside the buffer is established in the ALE coordinate system based on the finite volume method. Set loads and boundary conditions, including fixing the outer cylinder of the buffer, applying a displacement-time curve to the piston rod end to simulate landing impact, and defining the fluid-structure interaction interface; The structural model and the fluid model are integrated in the fluid-structure interaction solver; Performing fluid-structure interaction (FSI) solutions, which includes: S1. At the fluid-structure interaction interface, the pressure data calculated by the fluid model is transmitted to the structural model; S2. The displacement and velocity data calculated by the structural model are passed to the fluid model as moving boundary conditions; S3. Repeat S1 and S2 iteratively until the convergence criterion is met; Extract the dynamic response parameters of the buffer, including the buffer force-displacement curve.
[0018] Furthermore, the process of establishing the structural model of the buffer includes: In the ADINA-Structure module, a geometric model including the outer cylinder, piston rod, and support structure is established based on the actual three-dimensional geometric dimensions of the buffer. Assign the material properties of titanium-based composite materials to the geometric model; The geometric model is meshed using finite element methods, solid element types are selected, and the mesh is refined for stress concentration areas.
[0019] Furthermore, the process of establishing a fluid model of the oil inside the buffer includes: In the ADINA-CFD module, a geometric model of the fluid domain is established based on the actual geometry of the internal chamber of the buffer. The fluid domain includes the main oil chamber, the throttle valve and its connecting flow channel, the oil circulation channel, and the piston movement clearance area. To impart material properties to the fluid domain; Select the Navier-Stokes equations as the governing equations and enable the weakly compressible flow option.
[0020] Furthermore, the process of setting loads and boundary conditions includes: Set the mounting end of the buffer outer cylinder as a fixed constraint; A displacement-time curve obtained by fitting drop test data is applied to the piston rod end; The surfaces of the piston rod, piston head, and inner wall of the cylinder that come into contact with the oil are defined as fluid-structure interaction interfaces.
[0021] Furthermore, the process of integrating the structural model and the fluid model in the fluid-structure interaction solver is performed in the ADINA-FSI module; The fluid-structure interaction interface includes the piston rod surface, the piston head end face, and the inner wall of the cylinder.
[0022] Furthermore, the process of performing fluid-structure interaction solutions also includes using an implicit time integration algorithm for solving the problem; Combined with a strongly coupled solution strategy; Set adaptive time step; The convergence tolerances for force and displacement are set as convergence criteria.
[0023] Furthermore, the process of extracting the dynamic response parameters of the buffer includes: Obtain structural responses, including displacement-time curves, velocity-time curves, and acceleration-time curves of the piston rod, as well as stress distribution cloud maps and strain distribution cloud maps of key components; Obtain the flow field response, including pressure distribution cloud map, flow velocity vector map, and pressure-time curves at key locations within the oil cavity; Obtain the buffer force-displacement curve.
[0024] Furthermore, the titanium-based composite material exhibits orthogonal anisotropy.
[0025] Specifically, the implementation process of this embodiment includes: Step 1: Construction of a structural model based on the Lagrangian coordinate system Step 2: Constructing a fluid model based on the ALE coordinate system Step 3: Setting Loads and Boundary Conditions Step 4: Fluid-structure Interaction Solution and Dynamic Response Extraction Specifically, the implementation process of this embodiment includes: Step 1: This stage aims to accurately characterize the titanium-based composite material buffer structure. The specific implementation process is as follows: Geometric Modeling: In the ADINA-Structure module, a detailed geometric model is created based on the actual three-dimensional geometric dimensions of the buffer, including key components such as the outer cylinder, piston rod, and support structure.
[0026] Material property definition: This involves assigning mechanical property parameters to the model of the titanium-based composite material, including elastic modulus, Poisson's ratio, and density. These parameters are fundamental for accurately calculating structural stress and deformation.
[0027] Meshing: The geometric model is meshed using the finite element method. Appropriate element types (such as solid elements) are selected based on the characteristics of different components, and the mesh in critical areas (such as stress concentration areas) is ensured to be sufficiently refined to guarantee computational accuracy.
[0028] Step Two: This step aims to simulate the flow behavior of the oil inside the buffer and its interaction with the solid structure with high fidelity. The specific construction process and model structure are as follows: 1. Fluid Domain Geometric Modeling Model structure definition: Based on the actual geometry of the internal chambers of the buffer, a geometric model of the fluid domain is established in the ADINA-CFD module. For example... Figure 2 The model shown mainly includes the following key areas: gas chamber (high pressure chamber and low pressure chamber), main oil chamber, throttle valve and its connecting flow channel, oil circulation channel, and piston movement clearance area.
[0029] 2. Material Properties and Fluid Model Selection Oil parameter settings: Assign material properties to the fluid domain, mainly including density and dynamic viscosity. The material properties of hydraulic oil are shown in Table 1.
[0030] Table 1
[0031] Constitutive model: The Navier-Stokes equations, applicable to incompressible or weakly compressible fluids, are selected as the governing equations. Considering the slight compressibility that oil may exhibit under high pressure, a weakly compressible flow option can be enabled in the model to improve accuracy.
[0032] Step 3: This step aims to set the loads and boundary conditions, and the specific implementation is as follows: 1. Structural boundary conditions: Set the mounting end of the buffer outer cylinder as a fixed constraint.
[0033] 2. Motion load: A displacement-time curve obtained by fitting drop test data is applied to the end of the piston rod to simulate the impact load during aircraft landing.
[0034] 3. Fluid-Structure Interface: The surfaces of the piston rod, piston head end face, and inner wall of the cylinder that contact the oil are defined as the fluid-structure interaction interface. At this interface, bidirectional exchange of fluid pressure and structural displacement data will be achieved. Load and boundary condition settings are as follows... Figure 3 As shown.
[0035] Step Four: This step is the core of achieving high-precision simulation. It aims to solve the integrated model using the fluid-structure interaction solver in ADINA software and extract key dynamic response data. The specific implementation is as follows: 1. Model Integration and Two-Way Coupling Interface Settings After defining the structure and flow field models in the ADINA-Structure and ADINA-CFD modules respectively, they are integrated in the ADINA-FSI module.
[0036] Definition of bidirectional coupling interface: The boundary (piston rod surface, piston head end face, and inner wall of the cylinder) where the structural model and the fluid model come into contact is explicitly designated as the fluid-structure interaction interface. This invention employs a bidirectional coupling strategy, enabling real-time bidirectional exchange of physical quantities at this interface.
[0037] A two-way data transfer mechanism ensures the correct and synchronous transfer of physical quantities at the coupling interface. Its core mechanism is as follows: within each computation time step, the pressure data calculated in the fluid domain is transferred as a load to the structural model, while the displacement and velocity data calculated by the structural model are fed back as moving boundary conditions for the fluid domain. The ADINA solver automatically manages this closed-loop iterative process of "pressure → structural deformation → flow field boundary change → pressure redistribution," thereby achieving true two-way coupled simulation and accurately capturing the interaction between the fluid and the solid.
[0038] 2. Solver Setup and Calculation Execution After integrating the model, key solution parameters are set to start the simulation, ensuring the stability and accuracy of the bidirectional coupled problem: Solution algorithm selection: The implicit time integration algorithm provided by ADINA is used for the solution. This algorithm is suitable for solving dynamic problems, and combined with a strongly coupled (directly coupled) solution strategy, it can effectively handle strongly nonlinear problems caused by two-way fluid-structure interaction, ensuring that the fluid and structure fields reach equilibrium in each time step.
[0039] Time step control: A reasonable time step is set. To accurately capture the dynamic response during the impact process, an adaptive time step strategy is adopted. During the phase of drastic load changes (such as the instant of ground contact), the solver automatically reduces the step size to ensure the convergence of coupled iterations and computational accuracy; during the phase of gradual change, the step size is increased to improve computational efficiency.
[0040] Convergence Criterion Setting: To balance computational accuracy and efficiency, convergence tolerances for force and displacement are set during the coupled iteration process at each time step. When the change in the iterative calculation result is less than the preset tolerance, it is considered that the interaction between the fluid and the structure within that time step has been fully solved, and the solver proceeds to the next time step.
[0041] 3. Extraction and analysis of dynamic response results After the simulation is completed, key dynamic response data are extracted from the results file to evaluate the buffer's performance. Thanks to the two-way coupled simulation, the following results all include the combined effects of fluid-structure interaction: Result type: Obtain the following time-varying curves and contour plots through the post-processor: Structural response: displacement-time, velocity-time, and acceleration-time curves of the piston rod; stress distribution cloud maps and strain distribution cloud maps of key components (such as titanium-based composite outer cylinder), the results of which already include the effect of hydraulic load.
[0042] Flow field response: pressure distribution cloud map and velocity vector map in the oil cavity; pressure-time curves at key locations (such as both sides of the throttling orifice), whose flow field morphology is directly affected by structural deformation and motion.
[0043] Comprehensive performance indicators: The most important is the buffer force-displacement curve, as shown below. Figure 4 As shown in the figure, this curve is the core basis for evaluating the energy absorption characteristics of the buffer. It is formed by the bidirectional coupling of the hydraulic pressure acting on the piston by the flow field and the elastic force generated by the structural deformation. Its accuracy directly reflects the advantages of the method of this invention.
[0044] Results Analysis: By analyzing the above curves and contour maps, the complete working process of the buffer under impact load can be observed intuitively, and its damping characteristics, energy absorption efficiency, and structural strength can be evaluated. For example, the area enclosed by the buffer force-displacement curve directly reflects the energy absorbed by the buffer in one stroke, while the stress contour map is used to verify the safety of the titanium-based composite structure.
[0045] 6) Compared with the prior art, the present invention has advantages and effects, such as improved performance and reduced cost.
[0046] Example: Performance evaluation and optimization of titanium-based composite main landing gear buffers for a certain type of civil aircraft This example strictly follows the process of this invention to establish a two-way fluid-structure interaction model.
[0047] Step 1: In ADINA-Structure, a detailed 3D geometric model including components such as the titanium-based composite outer cylinder and the alloy steel piston rod was created based on the design drawings. The titanium-based composite outer cylinder was assigned orthotropic parameters such as its elastic modulus and Poisson's ratio, accurately characterizing its true material properties. This directly addresses the problem of "incomplete characterization of material properties."
[0048] Step 2: In ADINA-CFD, a fluid domain model was established strictly according to the actual flow channels such as the internal chambers, throttling orifices, and gaps of the buffer. The density and viscosity of the hydraulic oil were set, and a weakly compressible flow model was enabled to simulate the compressibility effect of the oil under high pressure (possibly exceeding 30 MPa), a detail that is usually ignored by traditional methods.
[0049] Step 3: Set the outer cylinder mounting surface as a fixed constraint. The displacement load applied to the piston rod end is not a simple uniform motion, but an impact displacement-time curve fitted based on the measured data of the drop test of this model, thus realistically simulating the landing impact.
[0050] Step 4: Integrate the model in the ADINA-FSI module, correctly defining the piston rod surface, inner wall of the cylinder, etc., as fluid-structure interaction interfaces. An implicit time integration and adaptive time step strategy are employed to ensure the stability and efficiency of solving the strongly nonlinear coupling problem.
[0051] Comparison with traditional methods: Traditional unidirectional coupling or pure fluid dynamics methods typically assume that piston motion is pre-defined or ignore the reaction of structural deformation to the flow field shape. For example, it ignores the effect of the minute expansion of the titanium-based composite outer cylinder under high pressure on the volume and pressure of the oil cavity.
[0052] In the bidirectional coupled simulation of this example, when the piston compresses the oil, the resulting high pressure acts as a load on the inner wall of the titanium-based composite outer cylinder, causing a slight expansion (strain) in the outer cylinder. This expansion, in turn, slightly increases the volume of the oil cavity, instantaneously reducing the pressure inside the cavity, thereby affecting the oil velocity and damping force flowing through the throttling orifice. This real-time, bidirectional interaction is completely captured. The final extracted buffer force-displacement curve is in high agreement with the results of subsequent physical experiments, and the calculation error of the area enclosed by the curve (representing the energy absorption capacity) is less than 5%, while the error of traditional methods may be as high as 15-20%. This proves that the present invention can evaluate the energy absorption characteristics of the buffer with extremely high accuracy.
[0053] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A method for fluid-structure interaction and modeling of titanium-based composite landing gear buffers, characterized in that, include: A structural model of the buffer is established in the Lagrangian coordinate system based on the finite element method. A fluid model of the oil inside the buffer is established in the ALE coordinate system based on the finite volume method. Set loads and boundary conditions, including fixing the outer cylinder of the buffer, applying a displacement-time curve to the piston rod end to simulate landing impact, and defining the fluid-structure interaction interface; The structural model and the fluid model are integrated in the fluid-structure interaction solver; Performing fluid-structure interaction (FSI) solutions, which includes: S1. At the fluid-structure interaction interface, the pressure data calculated by the fluid model is transmitted to the structural model; S2. The displacement and velocity data calculated by the structural model are passed to the fluid model as moving boundary conditions; S3. Repeat S1 and S2 iteratively until the convergence criterion is met; Extract the dynamic response parameters of the buffer, including the buffer force-displacement curve.
2. The method for fluid-structure interaction and modeling of titanium-based composite landing gear buffers as described in claim 1, characterized in that, The process of establishing a structural model for a buffer includes: In the ADINA-Structure module, a geometric model including the outer cylinder, piston rod, and support structure is established based on the actual three-dimensional geometric dimensions of the buffer. Assign the material properties of titanium-based composite materials to the geometric model; The geometric model is meshed using finite element methods, solid element types are selected, and the mesh is refined for stress concentration areas.
3. The method for fluid-structure interaction and modeling of titanium-based composite landing gear buffers as described in claim 1, characterized in that, The process of establishing a fluid model of the oil inside the buffer includes: In the ADINA-CFD module, a geometric model of the fluid domain is established based on the actual geometry of the internal chamber of the buffer. The fluid domain includes the main oil chamber, the throttle valve and its connecting flow channel, the oil circulation channel, and the piston movement clearance area. To impart material properties to the fluid domain; Select the Navier-Stokes equations as the governing equations and enable the weakly compressible flow option.
4. The method for fluid-structure interaction and modeling of titanium-based composite landing gear buffers as described in claim 1, characterized in that, The process of setting loads and boundary conditions includes: Set the mounting end of the buffer outer cylinder as a fixed constraint; A displacement-time curve obtained by fitting drop test data is applied to the piston rod end; The surfaces of the piston rod, piston head, and inner wall of the cylinder that come into contact with the oil are defined as fluid-structure interaction interfaces.
5. The method for fluid-structure interaction and modeling of titanium-based composite landing gear buffers as described in claim 1, characterized in that, The process of integrating the structural model and the fluid model in the fluid-structure interaction solver is performed in the ADINA-FSI module; The fluid-structure interaction interface includes the piston rod surface, the piston head end face, and the inner wall of the cylinder.
6. The method for fluid-structure interaction and modeling of titanium-based composite landing gear buffers as described in claim 1, characterized in that, The process of performing fluid-structure interaction (FSI) solutions also includes using implicit time integration algorithms for solving the problem; Combined with a strongly coupled solution strategy; Set adaptive time step; The convergence tolerances for force and displacement are set as convergence criteria.
7. The method for fluid-structure interaction and modeling of titanium-based composite landing gear buffers as described in claim 1, characterized in that, The process of extracting the dynamic response parameters of the buffer includes: Obtain structural responses, including displacement-time curves, velocity-time curves, and acceleration-time curves of the piston rod, as well as stress distribution cloud maps and strain distribution cloud maps of key components; Obtain the flow field response, including pressure distribution cloud map, flow velocity vector map, and pressure-time curves at key locations within the oil cavity; Obtain the buffer force-displacement curve.
8. The method for fluid-structure interaction and modeling of titanium-based composite landing gear buffers as described in claim 2, characterized in that, The titanium-based composite material has orthogonal anisotropy.