Aero-Structural Coupling Analysis Method during the Tilting Process of a Tilted Ducted Fan Aircraft

Abstract

The present invention proposes an aerodynamic-structural coupling analysis method for a tilting ducted fan aircraft during its tilting process, which can be used to analyze the entire aircraft or key components of various types of tilting ducted fan aircraft during their tilting process, and obtain characteristic data of the complete tilting process of the tilting ducted fan aircraft, including aerodynamic performance data and structural performance data, as well as their distribution and change trends. The present invention also proposes an aerodynamic-structural coupling analysis system for a tilting ducted fan aircraft during its tilting process, including a tilting process modeling module, a characteristic data acquisition module, and a characteristic data analysis module. The aerodynamic-structural coupling calculation in the characteristic data acquisition module adopts a modular design, and submodules of different accuracy and calculation speed can be replaced according to specific needs during operation, thereby improving practicality; it also innovatively adopts model transfer technology to reduce the overall number of calculations, thereby improving calculation efficiency.

Description

Technical Field

[0001] The present invention relates to the field of tilt-ducted fan aircraft design, and in particular to an aerodynamic-structural coupling analysis method and system for a tilt-ducted fan aircraft during its tilting process. Background Art

[0002] A tilt-duct fan aircraft (tilt-duct fan aircraft), also known as a tilt-duct aircraft, is a new type of vertical take-off and landing aircraft that combines ducted fans and tilt technology. It usually includes one or more pairs of ducted fans that can tilt to change the aircraft's flight mode. This aircraft combines the advantages of multi-rotor aircraft and fixed-wing aircraft. The ducts in its propulsion system and the fans in the ducts can be tilted as a whole within a range of 90 degrees with the fuselage axis as a reference, thereby flexibly switching between fixed-wing flight mode and multi-rotor flight mode. It not only retains the vertical take-off and landing capability of multi-rotor aircraft, but also has the advantage of high-speed cruising of fixed-wing aircraft. It is an important carrier of the low-altitude economy, providing efficient and flexible services to many fields, effectively promoting the prosperity and development of the low-altitude economy, and is the vertical take-off and landing aircraft with the most development potential in the future.

[0003] A ducted fan typically consists of a rotor (propeller) and a surrounding duct. Ducted fans generate thrust by pushing air through the duct. The duct structure enhances airflow control, improving propulsion efficiency, reducing noise, and protecting the rotor (propeller).

[0004] Compared with traditional rotor and other power devices, ducted fans have advantages in propulsion efficiency and noise reduction, but they also increase technical complexity, including the difficulty of aerodynamic and structural design. When the aircraft is installed with a tilt-ducted device, the technical challenges are particularly prominent, mainly reflected in the aircraft's aerodynamic and structural coupling effects, system integration and control, etc.

[0005] The key components of a tilt-ducted fan aircraft are the aerodynamic components directly mounted with the tilt-ducted fan. These key components must withstand the thrust, gravity, and aerodynamic loads of the tilt-ducted fan in different flight modes. Therefore, they must simultaneously meet the requirements of structural strength, rigidity, and aerodynamic performance. The design of these key components is the focus of the overall aircraft design. The installation location of the tilt-ducted fan is relatively flexible. It can be installed in different locations such as the wings, canards, tail ends, or fuselage of the tilt-ducted fan aircraft according to the specific design requirements of each aircraft. The number of ducted fans is generally 2 to 6.

[0006] The complete flight phase of a tilt-tufted fan aircraft includes five phases: vertical takeoff, tilt 1, level flight, tilt 2, and vertical landing. The angle formed between the axis of the ducted fan of the tilt-tufted fan aircraft and the longitudinal axis of the fuselage is defined as the tilt angle Alpha of the tilt-tufted fan aircraft. The complete flight phase of the tilt-tufted fan aircraft and the tilt change process of its ducted fan are as follows: Figure 1 As shown (taking the aircraft with tilted ducted fan devices installed on the wings and canards as an example): (1) Stage 1 is the vertical takeoff stage. At this time, the aircraft is in multi-rotor mode, the duct is vertically upward, the tilt angle of the ducted fan is Alpha = 90°, the ducted fan generates vertical upward thrust, and the aircraft takes off vertically. (2) Stage 2 is the tilt 1 stage. The aircraft switches from multi-rotor mode to fixed-wing mode. When the tilted ducted fan aircraft reaches the specified altitude, the ducted fan gradually tilts around the tilt center, and its tilt angle Alpha changes continuously from 90° to 0°. The thrust direction of the ducted fan gradually changes from vertical upward to horizontal forward as the ducted fan tilts. At the same time, it is necessary to coordinate the thrust distribution to ensure that the aircraft maintains a stable flight attitude. (3) Stage 3 is the level flight stage. At this time, the aircraft is in fixed-wing mode. The fan axis of the tilted ducted fan aircraft is parallel to the longitudinal axis of the fuselage, that is, the tilt angle Alpha = 0°. The ducted fan provides horizontal forward thrust, and the wings generate lift to maintain horizontal cruising flight. (4) Stage 4 is the tilt 2 stage, during which the aircraft switches from fixed-wing mode to multi-rotor mode. When the tilt-fan aircraft reaches the predetermined waypoint, the ducted fan tilts again, with its tilt angle Alpha continuously changing from 0° to 90°. The tilting process is the opposite of that in the tilt 1 stage. (5) Stage 5 is the vertical landing stage, during which the aircraft is in multi-rotor mode, with the ducted fan axis pointing vertically upward and the tilt angle Alpha = 90°. The ducted fan generates a vertical upward reverse thrust, and the aircraft slowly descends to the ground.

[0007] The tilt phase is a critical stage for a tilt-ducted fan aircraft to switch between multi-rotor mode and fixed-wing mode. During this period, the aircraft's airflow environment and structural state are extremely complex. This is specifically manifested in: ① Uneven airflow distribution. During the tilt process, the airflow environment undergoes drastic changes. The angle of attack of the wing and ducted fan, the relative wind speed, and other factors will constantly change, leading to rapid changes in aerodynamic characteristics (such as lift and drag). At the same time, unsteady airflow phenomena such as vortex shedding, turbulence enhancement, and wake interference will also occur, affecting the overall stability and control accuracy of the aircraft. ② Complex structural response under multiple loads. Compared with the relatively stable external loads in vertical take-off and landing and fixed-wing modes, during the tilt process, as the duct tilt angle changes, the aerodynamic load and ducted thrust load also change continuously. This superposition of multiple loads will cause complex stress distribution and structural deformation in the structural components.

[0008] Therefore, it is particularly important to accurately grasp and analyze the airflow conditions and structural changes of tilt-ducted fan aircraft during the tilting process for its design. Studying these changes will help to better understand the aerodynamic instability, structural stress concentration or vibration phenomena that may occur during the tilting process, so as to improve the design of the aircraft in a targeted manner, enhance its safety and stability, and ensure reliable flight under complex operating conditions.

[0009] Existing studies have separately analyzed the aerodynamic and structural changes in tilt-turn ducted fan aircraft during the tilting process. While these single-disciplinary research results provide some insights for aircraft design, the lack of systematic consideration of the interplay between aerodynamics and structure (i.e., aerodynamic-structural coupling) results in low prediction accuracy for aerodynamic and structural performance, making them difficult to meet practical application requirements. Aerodynamic-structural coupling analysis, on the other hand, comprehensively considers the interplay between aerodynamics and structure in tilt-turn ducted fan aircraft, enabling more accurate assessment of their aerodynamic and structural performance. Its core approach is to comprehensively evaluate the aerodynamic and structural responses of key components of tilt-turn ducted fan aircraft during flight through methods such as numerical simulation. During flight, key components are subjected to aerodynamic forces, generating aerodynamic loads such as lift and drag. Simultaneously, the structures of these components undergo deformation and stress distribution changes under the influence of aerodynamic and other loads. These structural changes, in turn, affect the flow characteristics of the airflow, which in turn influences the aerodynamic load distribution, ultimately leading to further changes in the structural response. Aerodynamic-structural coupling analysis achieves a balance between aerodynamic loads and structural deformation through multiple iterative calculations, providing a high-precision basis for design optimization.

[0010] Current research on aerodynamic-structural coupling for tilt-ducted fan aircraft primarily focuses on a single flight mode, while research on the tilting process is relatively lacking, particularly without addressing key components such as ducted wings, canards, tailplanes, and fuselages. While the conceptual design of the wing structure disclosed in Chinese Patent (202410621455.9) involves aerodynamic-structural coupling, as a submodule within an overall optimization system, only analyzes aerodynamic-structural coupling for level flight and vertical takeoff and landing during the conceptual design phase to simplify the problem, omitting the more complex tilting process. Furthermore, the patent's research focuses primarily on wings equipped with tilt-ducted devices, making it difficult to expand to other key components such as the fuselage and tailplane, posing certain limitations.

[0011] In contrast, aerodynamic-structural coupling analysis methods for conventional fixed-wing aircraft wings are relatively mature, as fixed-wing aircraft wings typically only need to withstand stable aerodynamic loads. However, key components of tilt-ducted fan aircraft (such as wings with tilt-ducted wingtips) must withstand not only varying aerodynamic loads during the tilting process, but also the gravity of the duct and complex, varying thrust loads. Therefore, the aerodynamic-structural coupling analysis methods developed for fixed-wing aircraft are not applicable to tilt-ducted fan aircraft with complex, varying loads and cannot effectively meet specific requirements. It is also noted that relevant aerodynamic-structural coupling analysis studies have been conducted for more mature tilt-rotor aircraft, but these studies have focused on structural flutter. During flight, due to the large rotor diameter of a tilt-rotor aircraft, the wake generated by the rotor directly affects aerodynamic components such as the wing and fuselage, thereby affecting the aerodynamic performance of these components. Tilt-ducted fan aircraft are more complex than tilt-rotor aircraft in terms of aerodynamic design, control systems, structural coupling, manufacturing and maintenance. This complexity not only increases the difficulty of design and manufacturing, but also imposes higher control requirements. Therefore, directly applying existing tilt-rotor aircraft design concepts to the design of tilt-ducted fan aircraft faces significant technical obstacles and is not easy to achieve.

[0012] In summary, the problems existing in the prior art are:

[0013] (1) Regarding the coupled analysis of aerodynamic and structural performance of tilting ducted fan aircraft, existing research mostly focuses on single flight modes such as level flight or vertical take-off and landing, and lacks research on the tilting process.

[0014] (2) Existing aerodynamic-structural coupling analysis methods for fixed-wing aircraft are mainly aimed at stable aerodynamic load conditions and cannot be applied to the tilting phase of tilt-ducted fan aircraft. During this phase, the aircraft must simultaneously withstand rapidly changing aerodynamic loads, the gravity of the ducted fan, and complex thrust changes.

[0015] (3) Compared with other vertical take-off and landing aircraft (such as tiltrotor aircraft), tilt-ducted fan aircraft are more complex in terms of aerodynamic design, control system, structural coupling, manufacturing and maintenance. Existing aerodynamic-structural coupling analysis methods related to vertical take-off and landing aircraft are difficult to adapt to the design requirements of tilt-ducted fan aircraft, which has become one of the technical bottlenecks. Summary of the Invention

[0016] Based on this situation, in order to accurately analyze the aerodynamic-structural coupling effect of a tilt-ducted fan aircraft during the tilting process, the present invention proposes an aerodynamic-structural coupling analysis method for a tilt-ducted fan aircraft during the tilting process. This method can be used to analyze key components of various types of tilt-ducted fan aircraft, can cope with complex aerodynamic and load changes during the tilting process, realize the coupling analysis of aerodynamic performance and structural performance, and provide a scientific basis for the subsequent design of tilt-ducted fan aircraft.

[0017] In order to achieve the above technical effects, the technical solution of the present invention is as follows: an aerodynamic-structural coupling analysis method for a tilting ducted fan aircraft during the tilting process, the method comprising:

[0018] S1: Construct a mathematical model of the tilting process to generate a tilting specific data stream of the tilting ducted fan aircraft during the tilting process; wherein the tilting specific data stream includes the incoming flow conditions and ducted load data at each moment in the tilting process, and the moment is obtained by dividing the duration of the tilting process. A moment, ; Preferably, the moment is divided evenly according to the duration of the tilting process;

[0019] S2: Obtain characteristic data of key components of tilt-ducted fan aircraft at all times during the tilting process

[0020] S21: Obtain the initial aerodynamic model at time i, ,like , then the initial aerodynamic model at time i is the original aerodynamic model of the key component. , then the initial aerodynamic model at time i is the converged aerodynamic model at time i-1;

[0021] S22: Based on the structural model of the key component, the initial aerodynamic model at time i, the incoming flow condition at time i, and the duct load data at time i, perform an aerodynamic-structural coupling calculation to obtain characteristic data and a converged aerodynamic model at time i. The aerodynamic-structural coupling calculation is an iterative calculation process, and each iterative calculation obtains an updated aerodynamic model. The aerodynamic model when the iterative calculation reaches the convergence condition is the converged aerodynamic model.

[0022] S23: Repeat steps S21 and S22. times, get Characteristic data at each moment;

[0023] The characteristic data includes aerodynamic performance data and structural performance data; the aerodynamic performance data includes but is not limited to the lift, drag, lift-to-drag ratio, and pressure coefficient of the key components; the structural performance data includes but is not limited to the displacement, stress, strain, and failure factor of the key components;

[0024] S3: Based on the characteristic data at all moments in the tilting process, the aerodynamic-structural coupling analysis results of the complete tilting process are obtained; wherein, the aerodynamic-structural coupling analysis results of the complete tilting process include a distribution diagram of the characteristic data at each moment on key components and a curve of the characteristic data changing with time.

[0025] The present invention divides the duration of a tilting ducted fan aircraft's tilting process into several moments, and calculates aerodynamic-coupling analysis to obtain aerodynamic and structural performance data at each moment. Based on the characteristic data at all moments, an aerodynamic-coupling analysis result for the complete tilting process is obtained. Furthermore, the aerodynamic-structural coupling calculation at moment i includes:

[0026] S221: Based on the initial aerodynamic model at time i and the incoming flow conditions at time i, an aerodynamic solver is used to perform calculations to obtain aerodynamic performance data;

[0027] S222: Inputting the pressure coefficient in the aerodynamic performance data into a load transfer module for calculation to obtain aerodynamic force and transfer it to the structural model of the key component;

[0028] S223: Based on the structural model of the key component, the aerodynamic force, and the duct load data at time i, a structural solver is used to perform calculations to obtain structural performance data;

[0029] S224: Inputting the displacement in the structural performance data into a displacement transfer module for calculation to obtain an updated aerodynamic model at time i;

[0030] S225: Determine whether the calculation has reached the convergence condition. If so, output the characteristic data and converged aerodynamic model at time i, where the characteristic data at time i includes the aerodynamic performance data and structural performance data obtained from this calculation. Otherwise, repeat steps S221 to S224 based on the updated aerodynamic model at time i.

[0031] Furthermore, the key components are aerodynamic components of a tilt-ducted fan aircraft equipped with a tilt-ducted fan, including but not limited to wings, canards, tail and fuselage of the tilt-ducted fan aircraft equipped with a tilt-ducted fan.

[0032] Furthermore, the incoming flow conditions include the angle of attack and airspeed of key components of the tilt-ducted fan aircraft.

[0033] Furthermore, the ducted load data includes the ducted thrust and ducted weight of each duct of the key components of the tilt-ducted fan aircraft.

[0034] Furthermore, the aerodynamic solver is implemented using a computational fluid dynamics method, which meshes the aerodynamic model of key components of a tilting ducted fan aircraft and obtains aerodynamic performance data by solving control equations on the mesh.

[0035] Furthermore, the structural solver is implemented using the finite element method, which uses a discretization method to divide the structural model of the key components of the tilt-ducted fan aircraft into a finite number of units, and obtains structural performance data by solving the mechanical equilibrium equations of each unit.

[0036] Furthermore, the load transfer module transfers the aerodynamic force in the aerodynamic model to the structural model through a weight function, which is specifically implemented as follows:

[0037] The load transfer module first converts the pressure data into aerodynamic mesh nodes in the aerodynamic model The aerodynamic force on the aerodynamic model is then The aerodynamic forces on the structure are transferred to the structural mesh nodes in the structural model. On the other hand, it is converted into aerodynamic forces that can be used for structural solution, assuming is the aerodynamic force on the mesh nodes of the aerodynamic model, is the aerodynamic force on the grid nodes of the structural model, which is expressed by the weight matrix For transfer, the formula is as follows:

[0038]

[0039] Among them, the weight matrix Elements Calculated based on distance: , Represents the mesh nodes of the aerodynamic model To the structural model mesh node The distance function. Representation and structural model mesh nodes All relevant aerodynamic model mesh nodes The sum of the distance functions.

[0040] Furthermore, the displacement transfer module transfers the displacement in the structural model to the aerodynamic model through a weight function, and the specific implementation is as follows:

[0041] The displacement transfer module transfers the displacement data in the structural performance data, that is, the displacement data of the structural grid nodes in the structural model. The displacement is transferred to the aerodynamic mesh nodes in the aerodynamic model Above, assuming is the displacement on the mesh node of the structural model, is the displacement on the grid node of the aerodynamic model, which is transferred through the weight matrix W. The formula is as follows:

[0042]

[0043] Furthermore, the convergence conditions include:

[0044] The norm of the total residual of the performance data calculated between the two iterations is less than the preset convergence threshold;

[0045] Or, the number of iterative calculations reaches the preset maximum number of iterations;

[0046] The total residual of the performance data includes the structural residual and the aerodynamic residual. The norm calculation formula of the total residual is as follows:

[0047]

[0048] in, is the total residual The norm of The total residual A quantity, The residuals represent the residuals of all physical quantities, including structural and aerodynamic residuals. Structural residuals refer to the node displacements and stress imbalances in the aircraft's structural model caused by aerodynamic forces during the tilting process of a tilt-ducted fan aircraft. They are typically used to measure errors in structural calculations. Aerodynamic residuals refer to the deviations of flow field variables, such as velocity and pressure, from actual flow conditions caused by structural deformation in the aerodynamic model during the tilting process of a tilt-ducted fan aircraft. They are used to measure errors in aerodynamic calculations.

[0049] The present invention also provides an aerodynamic-structural coupling analysis system for a tilting ducted fan aircraft during its tilting process, which can implement the aerodynamic-structural coupling analysis method for a tilting ducted fan aircraft during its tilting process, and includes:

[0050] The tilt process modeling module is used to generate a tilt-specific data stream of the tilt ducted fan aircraft during the tilt process; wherein the tilt-specific data stream includes the incoming flow conditions and ducted load data at each moment in the tilt process, and the moment is obtained by dividing the tilt process duration. A moment, ;

[0051] The characteristic data acquisition module is used to obtain characteristic data of key components of the tilting ducted fan aircraft at all times during the tilting process, including:

[0052] Get the initial aerodynamic model at time i, ,like , then the initial aerodynamic model at time i is the original aerodynamic model of the key component. , then the initial aerodynamic model at time i is the converged aerodynamic model at time i-1;

[0053] Based on the structural model of the key components, the initial aerodynamic model at time i, the incoming flow condition at time i, and the duct load data at time i, characteristic data and a converged aerodynamic model at time i are obtained through aerodynamic-structural coupling calculation; wherein the aerodynamic-structural coupling calculation is an iterative calculation process, and each iterative calculation obtains an updated aerodynamic model. The aerodynamic model when the iterative calculation reaches the convergence condition is the converged aerodynamic model.

[0054] Repeat the above steps for a total of times, get Characteristic data at each moment;

[0055] The characteristic data includes aerodynamic performance data and structural performance data; the aerodynamic performance data includes the lift, drag, lift-to-drag ratio, and pressure coefficient of the key components; the structural performance data includes the displacement, stress, strain, and failure factor of the key components;

[0056] The characteristic data analysis module is used to obtain the aerodynamic-structural coupling analysis results of the complete tilting process based on the characteristic data at all moments in the tilting process; wherein the aerodynamic-structural coupling analysis results of the complete tilting process include the distribution diagram of the characteristic data at each moment on the key components and the curve of the characteristic data changing with time.

[0057] Compared with the prior art, the present invention provides an aerodynamic-structural coupling analysis method and system for a tilting ducted fan aircraft during its tilting process, which has the following beneficial effects:

[0058] (1) The aerodynamic-structural coupling calculation method proposed in this invention for the tilting process of key components of a tilting ducted fan aircraft can provide a new idea and method for studying the structural deformation and aerodynamic performance changes of a tilting ducted fan aircraft during the tilting process.

[0059] (2) Modular design of aerodynamic-structural coupling calculation: The aerodynamic solver, structural solver, load and displacement transfer modules with different accuracy and calculation speed can be replaced according to specific needs, which improves practicality.

[0060] (3) The model transfer technology is used to reduce the number of convergence calculations and thus improve the computational efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0062] Figure 1 This is a diagram of the changes in the ducted fan of a tilt-ducted fan aircraft during flight, where Alpha is the tilt angle of the ducted fan.

[0063] Figure 2 It is an analysis framework diagram of the aerodynamic-structural coupling analysis method of the tilting ducted fan aircraft during the tilting process of the present invention.

[0064] Figure 3 It is a flow chart of aerodynamic-structural coupling calculation at time x during the tilting process of the present invention.

[0065] Figure 4 2 is a diagram of airspeed changes in an embodiment of the present invention.

[0066] Figure 5 4 is a graph showing the vertical thrust provided by the duct over time in an embodiment of the present invention.

[0067] Figure 6 4 is a graph showing the change in horizontal thrust provided by the duct over time in an embodiment of the present invention.

[0068] Figure 7 Schematic diagram of the initial aerodynamic model at time 6 in an embodiment of the present invention.

[0069] Figure 8 Schematic diagram of the CSM model in an embodiment of the present invention.

[0070] Figure 9 Schematic diagram of the wing surface pressure coefficient after the aerodynamic-structural coupling calculation converges at time 6 in an embodiment of the present invention.

[0071] Figure 10 3 is a schematic diagram of the wing structure deformation after the aerodynamic-structural coupling calculation converges at time 6 in an embodiment of the present invention.

[0072] Figure 11 Schematic diagram of the KS failure factor of the wing structure after the aerodynamic-structural coupling calculation converges at time 6 in an embodiment of the present invention.

[0073] Figure 12 3 is a graph showing the maximum displacement changing with time during the tilting process in an embodiment of the present invention.

[0074] Figure 133 is a curve diagram of the lift-to-drag ratio changing with time during the tilting process in an embodiment of the present invention.

[0075] Figure 14 3 is a comparison chart of the number of iterations of aerodynamic-structural coupling calculations when the model transfer technology is used and when it is not used in an embodiment of the present invention. DETAILED DESCRIPTION

[0076] The present invention will be further described below in conjunction with Examples and accompanying drawings. It should be understood that the examples are only intended to illustrate the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit and scope of the present invention, variations and advantages that those skilled in the art can imagine are included in the present invention and are protected by the appended claims and their equivalents.

[0077] It should be understood that the term "a" should be understood as "at least one" or "one or more." That is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "a" should not be understood as limiting the quantity. In the present invention, except for names and terms that have been explicitly defined by the inventors, other names and terms are commonly used in the art.

[0078] In order to study the changes in aerodynamic performance and structural performance of tilting ducted fan aircraft under the combined effects of aerodynamics, ducted thrust and ducted gravity during the tilting process, and thus provide a scientific basis for subsequent optimization design.

[0079] In one embodiment of the present invention, an aerodynamic-structural coupling analysis method for a tilting ducted fan aircraft during its tilting process is proposed, which is used to analyze the characteristic data of key components of the tilting ducted fan aircraft during its tilting process. The key components are aerodynamic components equipped with tilting ducts, specifically including the wings, canards, tail, and fuselage of the tilting ducted fan aircraft equipped with tilting ducts. Figure 2 As shown, the aerodynamic-structural coupling analysis method of a tilting ducted fan aircraft during the tilting process of the present invention is as follows:

[0080] S1: Constructing a mathematical model of the tilting process to generate a tilting-specific data stream of a tilting ducted fan aircraft during the tilting process; wherein the tilting-specific data stream includes the incoming flow conditions and ducted load data at each moment in the tilting process; the tilting process is evenly divided into N moments according to the duration of the tilting process, ;

[0081] S2: Obtain characteristic data of key components of tilt-ducted fan aircraft at all times during the tilting process

[0082] S21: Obtaining an initial aerodynamic model at time i. If time i is the most initial time, the initial aerodynamic model at time i is the original geometric model of the key components of the tilting ducted fan aircraft; otherwise, the initial aerodynamic model at time i is the converged aerodynamic model at time i-1.

[0083] S22: Based on the structural model of the key components, the initial aerodynamic model at time i, the incoming flow conditions at time i, and the duct load data at time i, characteristic data and a converged aerodynamic model at time i are obtained through aerodynamic-structural coupling calculation;

[0084] The aerodynamic-structural coupling calculation at time i includes:

[0085] S221: Based on the initial aerodynamic model at time i and the incoming flow conditions at time i, an aerodynamic solver is used to perform calculations to obtain aerodynamic performance data;

[0086] S222: Inputting the pressure coefficient in the aerodynamic performance data into a load transfer module for calculation to obtain aerodynamic force and transfer it to the structural model of the key component;

[0087] S223: Based on the structural model of the key component, the aerodynamic force, and the duct load data at time i, a structural solver is used to perform calculations to obtain structural performance data;

[0088] S224: Inputting the displacement in the structural performance data into a displacement transfer module for calculation to obtain an updated aerodynamic model at time i;

[0089] S225: Determine whether the calculation has reached the convergence condition. If so, output the characteristic data and converged aerodynamic model at time i, where the characteristic data at time i includes the aerodynamic performance data and structural performance data obtained from this calculation. Otherwise, repeat steps S221 to S224 based on the updated aerodynamic model at time i.

[0090] S23: Repeat steps S21 and S22. times, get Characteristic data at each moment;

[0091] S3: Based on the characteristic data at all moments in the tilting process, the aerodynamic-structural coupling analysis results of the complete tilting process are obtained; wherein, the aerodynamic-structural coupling analysis results of the complete tilting process include a distribution diagram of the characteristic data at each moment on key components and a curve of the characteristic data changing with time.

[0092] In another embodiment of the present invention, the incoming flow condition is the external flow field information of the tilt-ducted fan aircraft, including the angle of attack and airspeed of the tilt-ducted fan aircraft. As the tilt angle of the tilt-ducted fan aircraft changes during the tilting process, the airspeed and angle of attack of the tilt-ducted fan aircraft are constantly changing, thereby affecting the aerodynamic performance of the tilt-ducted fan aircraft. The airspeed is the relative speed between the tilt-ducted fan aircraft and the incoming flow, and the angle of attack is the angle between the chord line of the tilt-ducted fan aircraft wing and the incoming flow direction. The duct load data includes the various ducted thrusts (including the direction and magnitude of the thrust) loaded on the key components of the tilt-ducted fan aircraft and the gravity of the corresponding duct. The tilt duct of the tilt-ducted fan aircraft can be one or more, and each duct does not have to be exactly the same.

[0093] In another embodiment of the present invention, the characteristic data at each moment includes aerodynamic performance data and structural performance data. The aerodynamic performance data characterizes the aerodynamic performance of the tilt-ducted fan aircraft during its tilting process, while the structural performance data characterizes the structural changes during the tilt-ducted fan aircraft's tilting process. The aerodynamic performance data includes lift, drag, lift-to-drag ratio, and pressure coefficient experienced by the aircraft during its tilting process. The structural performance data includes displacement (i.e., structural deformation), stress, strain, and failure factor of the aircraft during its tilting process.

[0094] The method of the present invention can analyze the aerodynamic-structural coupling of the entire tilt-ducted fan aircraft during the tilting process of the tilt-ducted fan aircraft, and can also analyze the aerodynamic-structural coupling of key components during the tilting process of the tilt-ducted fan aircraft. The key components refer to the parts of the tilt-ducted fan aircraft equipped with tilt-ducted devices. Usually, the tilt-ducted devices can be installed on the wings, canards, tail wings, and fuselage of the tilt-ducted fan aircraft. According to actual design requirements, there can be one or more tilt-ducted devices, and each duct does not have to be exactly the same. Multiple tilt-ducted devices can be installed in the same key component or in different key components.

[0095] In another embodiment of the present invention, the aerodynamic-structural coupling analysis results during the complete tilting process include a distribution diagram of characteristic data on key components at each moment and a curve of characteristic data changing with time.

[0096] In another embodiment of the present invention, the Newton-Krylov method is used to perform aerodynamic-structural coupling calculations to obtain characteristic data at time i. Newton-Krylov is a numerical algorithm primarily used to solve nonlinear partial differential equations. The specific process is as follows:

[0097] (1) Initialize an initial solution, which is an initial guess at the beginning of the solution process, including all variables in the aerodynamic model and the structural model;

[0098] (2) Calculate the total residual of the aerodynamic-structural coupling model

[0099] The total residual includes structural and aerodynamic residuals. The structural residual refers to the node displacements and stress imbalances in the aircraft's structural model caused by aerodynamic forces during the tilting process of a tilt-ducted fan aircraft. It is typically used to measure errors in structural calculations. The aerodynamic residual refers to the deviation of flow field variables such as velocity and pressure from actual flow conditions caused by structural deformation in the aerodynamic model during the tilting process of a tilt-ducted fan aircraft. It is used to measure errors in aerodynamic calculations.

[0100] assumed , Represent aerodynamic force and structural deformation respectively, and the aerodynamic grid nodes are , the structural load is , then the residual of the aerodynamic model is , the residual of the structural model is , the total residual of the aerodynamic-structural coupling model is expressed as:

[0101]

[0102] (3) Constructing a linearized system

[0103] The linear system is solved using the Krylov subspace method to update the solution. This process is repeated until the total residual error of the aerodynamic-structural coupling model meets the preset convergence criteria.

[0104] To use the fully coupled Newton-Krylov method to find a solution that satisfies the coupled residual equations Solution , first provide an initial solution , and then construct the linearized system at each iteration:

[0105]

[0106] in is the current solution The Jacobian matrix at , is the correction amount.

[0107] (4) Solve the linearized system, that is:

[0108]

[0109] The state variables after solution are updated as 、 .

[0110] (5) Final inspection Is it less than the given convergence threshold? If the condition is met, stop the iteration and return the solution. As a solution ; Otherwise, continue iterating.

[0111] In another embodiment of the present invention, Figure 3 As shown in Figure 2, taking a certain moment X between time 1 and time N as an example, the aerodynamic-structural coupling calculation process at time X is as follows:

[0112] (1) Input the incoming flow condition X and the duct load data X, where the incoming flow condition X includes the angle of attack A X and airspeed V X The duct load data X includes the duct thrust T of m ducts acting on the key components under analysis. X (T X1 , T X2 ,…,T Xm ) and duct gravity G X (G X1 , G X2 ,…,G Xm );

[0113] (2) The aerodynamic model after the aerodynamic coupling calculation converges at time X-1 is used as the initial aerodynamic model at time X, recorded as CFD model X_0, and the first coupling solution calculation is performed:

[0114] First, the CFD model X_0 is calculated using an aerodynamic solver based on the incoming flow condition X to obtain a set of aerodynamic performance data. The pressure coefficient in the aerodynamic performance data is converted into aerodynamic forces through the load transfer module. The aerodynamic forces and the ducted thrust TX and ducted weight GX from the duct load data X are loaded onto the CSM model and calculated using a structural solver to obtain structural performance data. The displacement data from the structural performance data is input into the displacement transfer module to deform the CFD model X_0, resulting in the CFD model X_1.

[0115] (3) Perform two coupled solution calculations based on the CFD model X_1;

[0116] (4) Repeat the above steps until the convergence condition is reached after the K+1th coupled solution is determined by the convergence judgment module, and the characteristic data at time X is output, including aerodynamic performance data and structural performance data. At the same time, the CFD model X_K is transferred to the aerodynamic-structural calculation at time X+1 and serves as the initial aerodynamic model at time X+1, recorded as CFD model (X+1)_0. At this point, the aerodynamic-structural coupled calculation at time X is completed.

[0117] Furthermore, the CFD model (Computational Fluid Dynamics), i.e., the aerodynamic model, is used to simulate the airflow around the key components being analyzed and calculate aerodynamic characteristics such as pressure coefficient, lift, drag, and airflow velocity.

[0118] Furthermore, the CSM model (computational structural mechanics), i.e., a structural model, is used to simulate the structural response of the key components being analyzed and calculate the structural characteristics such as stress, strain, and deformation of the structure under the action of aerodynamic forces. It is important to note that the CSM model always remains unchanged.

[0119] Furthermore, the aerodynamic solver calculates aerodynamic performance data based on CFD models of key components and incoming flow conditions. This data includes lift, drag, lift-to-drag ratio, and pressure coefficient. Users can employ high-precision aerodynamic analysis methods based on their actual needs. These methods can employ computational fluid dynamics (CFD) methods for high-precision analysis. By meshing the wing's three-dimensional geometric model and solving the flow field using the NS and RANS equations, more accurate parameters can be obtained.

[0120] Furthermore, the load transfer module obtains aerodynamic forces based on the pressure coefficient in the aerodynamic performance data and transfers them to the structural model of the key components;

[0121] Furthermore, the structural solver analyzes the wing structure based on the aerodynamic forces transmitted by the load transfer module, as well as the ducted thrust and gravity, to obtain structural performance data. This structural performance data includes displacement, stress, strain, failure factor, and more. Users can employ high-precision structural analysis methods to solve the structure based on their actual needs. These high-precision analysis methods can employ the finite element method (FEM). Using discretization, the structure is divided into a finite number of elements, and accurate structural performance is obtained by solving the mechanical equilibrium equations for each element.

[0122] Furthermore, the displacement transfer module feeds back the displacement data in the structural characteristic data to the CFD model to obtain a deformed CFD model.

[0123] Furthermore, the convergence judgment module is used to monitor the aerodynamic residuals and structural residuals during the iteration process until the convergence conditions are met. When the convergence conditions are met, the iteration is stopped and the final characteristic data is output. The aerodynamic residuals include lift coefficient residuals, drag coefficient residuals, etc.; the structural residuals include structural responses such as displacement residuals, etc. The convergence conditions include that when the change in the aerodynamic residuals and structural residuals calculated before and after two iterations is lower than a preset convergence threshold, it is determined that the convergence conditions are met. The preset convergence threshold is set by the user according to actual engineering needs.

[0124] In another embodiment of the present invention, an aerodynamic solver based on the RANS equations and the Spalart-Allmaras (SA) turbulence model is used to solve aerodynamic performance data at time i during the tilting process of a tilting ducted fan aircraft. The RANS equations describe the average flow behavior of the fluid, while the SA turbulence model provides an equation for calculating the turbulent viscosity coefficient, which affects the turbulent stress term in the RANS equations.

[0125] The RANS equation is decomposed into an average part and a pulsating part by time averaging, which is used to describe the average flow behavior in turbulent flow. The RANS equation is expressed as follows:

[0126] The mass conservation equation (continuity equation):

[0127] The momentum conservation equation (momentum equation):

[0128] in: is the average density, It's time, and represents the spatial coordinate component in the flow field, and are the components of the velocity vector (represented in and speed in the spatial direction), is the average pressure, is the viscous stress tensor, is the Reynolds stress, representing the contribution of the turbulent fluctuating velocity component.

[0129] Reynolds stress Through the turbulent viscosity coefficient Expressed as:

[0130]

[0131] in, is the turbulent kinetic energy, is the Kronecker function, the turbulent viscosity coefficient The calculation of requires the help of turbulence models, and the SA model is one of them.

[0132] The governing equations of the SA model are expressed as follows:

[0133]

[0134] in: is the improved turbulent viscosity coefficient, is the action amount, is the wall distance, which refers to the vertical distance from a point in the flow field to the nearest solid boundary (usually an airfoil or other wall). is the model constant, is a correction function based on turbulence characteristics.

[0135] Turbulent viscosity coefficient pass Calculation yields: ,in is the correction function.

[0136] In another embodiment of the present invention, a structural solver employs a finite element method (FEM)-based solver to perform linear static analysis on the structural performance data of a tilt-ducted fan aircraft at time i during the tilting process. This linear static analysis constructs a unit stiffness matrix, assembles a global stiffness matrix, solves for displacement vectors, and calculates stress and strain distributions. This analysis can analyze the static response of the tilt-ducted fan aircraft under complex loads during the tilting process. The specific steps for solving the structural performance data using linear static analysis are as follows:

[0137] (1) Constructing the element stiffness matrix

[0138] Element stiffness matrix is the stiffness matrix of each finite element, It is expressed as follows:

[0139]

[0140] in, is the unit volume, is the strain-displacement matrix, is the material stiffness matrix.

[0141] (2) Assembling the global stiffness matrix

[0142] Global stiffness matrix , all element stiffness matrices Assemble into a global stiffness matrix according to the node connection relationship .

[0143] (4) Constructing load vector

[0144] Load vector It includes the contributions of external concentrated forces and body forces. The external concentrated forces act directly on the nodes, while the body forces need to be converted into nodal forces through unit integration.

[0145] (5) Solve the displacement vector

[0146] Displacement Vector (Displacement Vector) by solving the global equilibrium equation get,

[0147] (6) Calculation of strain and stress

[0148] By displacement vector The strain and stress are further calculated.

[0149] In another embodiment of the present invention, the load and displacement transfer modules utilize MELD (matched load and displacement extrapolation), a multi-point explicit load and displacement transfer method widely used in aerodynamic-structural coupling analysis. MELD transfers aerodynamic loads and structural displacements between the CFD model and the CSM model using a weighting function. The weighting function is typically defined based on geometric parameters such as distance or area to ensure accuracy and stability during the transfer process.

[0150] 1) Load transfer: aerodynamic mesh nodes in CFD models The aerodynamic forces calculated above need to be transferred to the structural grid nodes in the CSM model Assume is the aerodynamic force on the aerodynamic grid nodes, is the force on the structural grid nodes, through the weight matrix To transfer:

[0151]

[0152] 2) Displacement transfer: Structural mesh nodes in the CSM model The calculated displacements need to be transferred to the aerodynamic mesh nodes in the CFD model Assume is the displacement on the structural mesh node is the displacement of the aerodynamic mesh node, through the weight matrix The transfer:

[0153]

[0154] Weight Matrix Elements Usually calculated based on distance:

[0155] in, Represents aerodynamic mesh nodes To the structural mesh node The distance function is usually the inverse distance squared. Representing and structuring mesh nodes All relevant aerodynamic mesh nodes The sum of the distance functions of . Represents all aerodynamic mesh nodes The index of the structure grid nodes is summed up to get the index of the structure grid nodes. Related aerodynamic mesh nodes Perform normalization processing.

[0156] In another embodiment of the present invention, the convergence condition is a crucial part of the method. It is responsible for evaluating the accuracy of the current solution and determining whether to continue iteration or terminate the calculation. The convergence condition is usually based on the size of the residual. For aerodynamic-structural coupling analysis, the aerodynamic residual and structural residual are mainly considered. The specific implementation process of the convergence judgment is as follows:

[0157] (1) Calculate the total residual and find its norm. The residual norm is expressed as follows:

[0158]

[0159] in is the total residual, The total residual A quantity, It is the residual of all physical quantities of structural residuals and aerodynamic residuals. The physical quantity residuals of aerodynamic residuals include lift coefficient residuals, drag coefficient residuals, etc. The physical quantity residuals of structural residuals include structural responses such as displacement residuals, etc.

[0160] (2) Compare the residual norm with the preset convergence threshold Make a comparison

[0161] if , that is, the residual norm is less than the threshold, indicating that the current solution is accurate enough, the iterative process converges, and the final aerodynamic and structural characteristics data are output.

[0162] if , that is, the residual norm is greater than or equal to the threshold, indicating that the current solution is not accurate enough, and the iterative calculation is continued, the solution is updated, and the residual is recalculated.

[0163] The preset convergence threshold is set by the user according to actual project requirements.

[0164] (3) Determine whether the number of residual iterations reaches the maximum number of iterations

[0165] If convergence is not achieved after the maximum number of iterations, a warning message is output or an attempt is made to adjust the initial solution or other parameters and restart the iteration.

[0166] In order to further illustrate the method described in the present invention, a typical key component of a 50 kg class tilting ducted fan aircraft is selected. Taking a wing with a tilting duct installed at the wingtip as an example, its aerodynamic performance data and structural mechanical performance data and their changing trends during the tilting process are analyzed. First, a mathematical model of the tilting process is constructed to generate a tilting specific data stream of the tilting ducted fan aircraft during the tilting process. The tilting specific data stream is derived from aircraft dynamics and related experiments and is known data. Among them, the tilting specific data stream includes the incoming flow conditions and duct load data at each moment in the tilting process. The incoming flow conditions include the angle of attack and airspeed of the tilting ducted fan aircraft at that moment, and the duct load data includes the duct thrust and corresponding duct weight of each duct of the tilting ducted fan aircraft at that moment.

[0167] Because the angle of attack of the aircraft does not change much during the tilting process, in order to reduce the calculation cost, it is assumed that the angle of attack is always kept at 3°, and the airspeed changes as follows Figure 4 As shown; the ducted thrust includes magnitude and direction, and is expressed in the form of horizontal and vertical components, as shown in Figure 5 and Figure 6 shown.

[0168] The tilting process lasts for 7 seconds, evenly divided into 20 moments, or N = 20. The tilting process duration is determined by flight dynamics simulation and related experiments, and the specific number of moments is determined based on the required data accuracy. Specifically, the analysis of moment 6 (i.e., X = 6) is divided into two parts:

[0169] Inflow Condition 6: Angle of Attack (unit is °), airspeed (unit: m / s);

[0170] Ducted load data 6: Ducted thrust (The tilt angle is 38.6°, equivalent to the vertical direction , horizontal direction ), ducted gravity (direction is vertically downward);

[0171] Before beginning aerodynamic-structural coupling calculations, a 3D wing model must be created using CAD software. This includes both the wing geometry model (for aerodynamic analysis) and the wing structure model (for structural analysis). Appropriate meshing and generation tools are then used to generate the corresponding CFD model for aerodynamic analysis and the CSM model for structural analysis.

[0172] The aerodynamic-structural coupling calculation process at time 6 is as follows:

[0173] First, the CFD model 5_K that finally converges at time 5 is used as the initial CFD model 6_0 at time 6, as shown in Figure 7 According to the incoming flow condition 6, the aerodynamic solver is used to calculate the flow field under this state on the CFD grid corresponding to the initial CFD model 6_0, extract the aerodynamic pressure distribution, and convert it into aerodynamic force through load transfer technology. And transfer it to the corresponding node of the CSM model grid. The CSM model is as follows Figure 8 As shown in the figure, the CSM model remains unchanged in the entire tilting process coupling analysis. and ducted gravity The CSM model is loaded onto the system. The structural deformation is then calculated using the structural solver. The structural displacements are then transferred using displacement transfer techniques to obtain the displacements of the corresponding nodes in the CFD mesh. A deformed CFD model 6_1 is then generated using the dynamic mesh algorithm, completing the first coupled solution. The aerodynamic solver then calculates new aerodynamic forces based on the 6_1 model mesh. This process is repeated until convergence conditions are met after the fifth coupled solution. The coupled calculation results for time 6 are then output. This concludes the wing aerodynamic-structural coupled calculation at time 6, outputting the characteristic data. CFD model 6_5 is then transferred to time 7, serving as the initial CFD model 7_0 for time 7.

[0174] In this embodiment, the aerodynamic-structural coupling analysis results of the complete tilting process will be obtained, including but not limited to the maximum displacement variation curve, the lift-to-drag ratio variation curve, the lift coefficient variation curve, the drag coefficient variation curve, as well as the pressure coefficient distribution cloud map at each moment, the KS failure factor cloud map, etc. Figure 9 This is a schematic diagram of the wing surface pressure coefficient after the aerodynamic-structural coupling calculation converges at time 6. Figure 10 This is a schematic diagram of the wing structure deformation after the aerodynamic-structural coupling calculation converges at time 6. Figure 11 This is a schematic diagram of the KS failure factor of the wing structure after the aerodynamic-structural coupling calculation converges at time 6. Figure 12 is the curve of maximum displacement changing with time during the tilting process, Figure 13 It is a curve diagram of the lift-to-drag ratio changing with time during the tilting process.

[0175] Compared with the prior art which uses the initial CFD model as input at each moment, the present invention uses the CFD model of the previous moment as input through the model transfer technology. The number of iterations at each moment of the two calculation methods is as follows: Figure 14As shown in the figure, using the model transfer technique of the present invention, a total of 100 iterations at 20 moments took 1626.17 seconds. Without the model transfer technique, a total of 192 iterations took 3736.72 seconds. The model transfer technique used in the present invention can reduce the number of calculation iterations by 47.9% and shorten the calculation time by 56.5%, greatly improving computational efficiency.

[0176] In summary, the present invention divides the tilting process of a tilt-ducted fan aircraft into different tilting moments according to the tilting time, obtains the coupling analysis of aerodynamic performance data and structural performance data when the aerodynamic model converges at each moment in the tilting process, and is used to guide the design of the tilt-ducted fan aircraft. The aerodynamic-structural coupling calculation method of the present invention adopts a modular design, and can replace aerodynamic solvers, structural solvers, load transfer modules, and displacement transfer modules with different accuracy and calculation speeds according to specific needs. The aerodynamic-structural coupling calculation method of the present invention adopts model transfer technology, and the converged aerodynamic model obtained at any moment is used as the initial aerodynamic model at the next moment, which can significantly reduce the number of iterations and improve calculation efficiency.

[0177] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0178] The above-mentioned specific implementation methods are used to illustrate the present invention and are only preferred embodiments of the present invention, rather than limiting the present invention. Any modifications, equivalent substitutions, improvements, etc. made to the present invention within the spirit of the present invention and the scope of protection of the claims shall fall within the scope of protection of the present invention.

Claims

1. A method for aerodynamic-structural coupling analysis of a tilting ducted fan aircraft during its tilting process, characterized in that: The method comprises: S1: Construct a mathematical model of the tilting process to generate a tilting specific data stream of the tilting ducted fan aircraft during the tilting process; wherein the tilting specific data stream includes the incoming flow conditions and ducted load data at each moment in the tilting process, and the moment is obtained by dividing the duration of the tilting process. A moment, ; S2: Obtain characteristic data of key components of tilt-ducted fan aircraft at all times during the tilting process S21: Obtain the initial aerodynamic model at time i, ,like , then the initial aerodynamic model at time i is the original aerodynamic model of the key component. , then the initial aerodynamic model at time i is the converged aerodynamic model at time i-1; S22: Based on the structural model of the key component, the initial aerodynamic model at time i, the incoming flow condition at time i, and the duct load data at time i, perform an aerodynamic-structural coupling calculation to obtain characteristic data and a converged aerodynamic model at time i. The aerodynamic-structural coupling calculation is an iterative calculation process, and each iterative calculation obtains an updated aerodynamic model. The aerodynamic model when the iterative calculation reaches the convergence condition is the converged aerodynamic model. S23: Repeat steps S21 and S22. times, get Characteristic data at each moment; The characteristic data includes aerodynamic performance data and structural performance data; the aerodynamic performance data includes the lift, drag, lift-to-drag ratio, and pressure coefficient of the key components; the structural performance data includes the displacement, stress, strain, and failure factor of the key components; S3: Based on the characteristic data at all moments in the tilting process, the aerodynamic-structural coupling analysis results of the complete tilting process are obtained; wherein, the aerodynamic-structural coupling analysis results of the complete tilting process include a distribution diagram of the characteristic data at each moment on key components and a curve of the characteristic data changing with time.

2. The method according to claim 1, characterized in that The aerodynamic-structural coupling calculation at time i includes: S221: Based on the initial aerodynamic model at time i and the incoming flow conditions at time i, an aerodynamic solver is used to perform calculations to obtain aerodynamic performance data; S222: Inputting the pressure coefficient in the aerodynamic performance data into a load transfer module for calculation to obtain aerodynamic force and transfer it to the structural model of the key component; S223: Based on the structural model of the key component, the aerodynamic force, and the duct load data at time i, a structural solver is used to perform calculations to obtain structural performance data; S224: Inputting the displacement in the structural performance data into a displacement transfer module for calculation to obtain an updated aerodynamic model at time i; S225: Determine whether the calculation has reached the convergence condition. If so, output the characteristic data and converged aerodynamic model at time i, where the characteristic data at time i includes the aerodynamic performance data and structural performance data obtained from this calculation. Otherwise, repeat steps S221 to S224 based on the updated aerodynamic model at time i.

3. The method according to claim 1, characterized in that The incoming flow conditions include the angle of attack and airspeed of key components of the tilt-ducted fan aircraft.

4. The method according to claim 1, wherein The ducted load data includes the ducted thrust and ducted weight of each duct of the key components of the tilt-ducted fan aircraft.

5. The method according to claim 2, characterized in that The aerodynamic solver is implemented using a computational fluid dynamics method, which meshes the aerodynamic model of key components of a tilting ducted fan aircraft and obtains aerodynamic performance data by solving control equations.

6. The method according to claim 2, characterized in that The structural solver is implemented using the finite element method, which uses a discretization method to divide the structural model of the key components of the tilting ducted fan aircraft into a finite number of units, and obtains structural performance data by solving mechanical equilibrium equations.

7. The method according to claim 2, characterized in that The load transfer module transfers the aerodynamic force in the aerodynamic model to the structural model through the weight function. The specific implementation method is as follows: Assumptions is the aerodynamic force on the mesh nodes of the aerodynamic model, is the aerodynamic force on the grid nodes of the structural model, which is expressed by the weight matrix For transfer, the formula is as follows: Among them, the weight matrix Elements Calculated based on distance: , Represents the mesh nodes of the aerodynamic model To the structural model mesh node The distance function, Representation and structural model mesh nodes All relevant aerodynamic model mesh nodes The sum of the distance functions.

8. The method according to claim 2, characterized in that The displacement transfer module transfers the displacement in the structural model to the aerodynamic model through a weight function. The specific implementation is as follows: Assumptions is the displacement on the mesh node of the structural model, is the displacement on the grid node of the aerodynamic model, which is transferred through the weight matrix W. The formula is as follows: 。 9. The method according to claim 1, characterized in that The convergence conditions include: The norm of the total residual of the performance data calculated between the two iterations is less than the preset convergence threshold; Or, the number of iterative calculations reaches the preset maximum number of iterations; The total residual of the performance data includes the structural residual and the aerodynamic residual. The norm calculation formula of the total residual is as follows: in, is the total residual The norm of The total residual A portion.

10. An aerodynamic-structural coupling analysis system for a tilting ducted fan aircraft during its tilting process, characterized in that: include: The tilt process modeling module is used to generate a tilt-specific data stream of the tilt ducted fan aircraft during the tilt process; wherein the tilt-specific data stream includes the incoming flow conditions and ducted load data at each moment in the tilt process, and the moment is obtained by dividing the tilt process duration. A moment, ; The characteristic data acquisition module is used to obtain characteristic data of key components of the tilting ducted fan aircraft at all times during the tilting process, including: Get the initial aerodynamic model at time i, ,like , then the initial aerodynamic model at time i is the original aerodynamic model of the key component. , then the initial aerodynamic model at time i is the converged aerodynamic model at time i-1; Based on the structural model of the key components, the initial aerodynamic model at time i, the incoming flow condition at time i, and the duct load data at time i, characteristic data and a converged aerodynamic model at time i are obtained through aerodynamic-structural coupling calculation; wherein the aerodynamic-structural coupling calculation is an iterative calculation process, and each iterative calculation obtains an updated aerodynamic model. The aerodynamic model when the iterative calculation reaches the convergence condition is the converged aerodynamic model. Repeat the above steps for a total of times, get Characteristic data at each moment; The characteristic data includes aerodynamic performance data and structural performance data; the aerodynamic performance data includes the lift, drag, lift-to-drag ratio, and pressure coefficient of the key components; the structural performance data includes the displacement, stress, strain, and failure factor of the key components; The characteristic data analysis module is used to obtain the aerodynamic-structural coupling analysis results of the complete tilting process based on the characteristic data at all moments in the tilting process; wherein the aerodynamic-structural coupling analysis results of the complete tilting process include the distribution diagram of the characteristic data at each moment on the key components and the curve of the characteristic data changing with time.

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