Pneumatic-structure coupling analysis method in tilting process of tilting ducted fan aircraft

Abstract

The invention provides a pneumatic-structure coupling analysis method in the tilting process of a tilting ducted fan aircraft, which can be used for analyzing complete machines or key parts of various types of tilting ducted fan aircrafts in the tilting process to obtain characteristic data of the tilting ducted fan aircrafts in the complete tilting process. Comprising aerodynamic performance data, structural performance data and distribution and change trends thereof. The invention further provides a pneumatic-structural coupling analysis system in the tilting process of the tilting ducted fan aircraft. The pneumatic-structural coupling analysis system comprises a tilting process modeling module, a characteristic data acquisition module and a characteristic data analysis module. Wherein pneumatic-structural coupling calculation in the characteristic data acquisition module adopts modular design, sub-modules with different precisions and calculation speeds can be replaced according to specific requirements in the operation process, and the practicability is improved; and a model transmission technology is innovatively adopted, so that the overall calculation frequency is reduced, and the calculation efficiency is further improved.

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] Tilt-duct fan aircraft, also known as tilt-duct aircraft, is a new type of vertical take-off and landing aircraft that combines ducted fans and tilt technology, usually including one or more pairs of ducted fans, which can be tilted to change the flight mode of the aircraft. This aircraft combines the advantages of multi-rotor aircraft and fixed-wing aircraft. The duct in its propulsion system and the fan in the duct can be tilted within 90 degrees with the fuselage axis as a reference, so as to flexibly switch 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 low-altitude economy, providing efficient and flexible services for many fields, effectively promoting the prosperity and development of low-altitude economy, and is the vertical take-off and landing aircraft with the most development potential in the future.

[0003] Ducted fans usually consist of a rotor (propeller) and a duct surrounding it. Ducted fans generate thrust by pushing the air in the duct, and use the duct structure to enhance airflow control, thereby improving propulsion efficiency, reducing noise, and providing protection for 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 the technical complexity, including the difficulty of aerodynamic and structural design. When the aircraft is equipped 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 refer to the aircraft's aerodynamic components that are directly equipped with tilt-ducted fans. These key components need to withstand the thrust and gravity from the tilt-ducted fans and aerodynamic loads in different flight modes, so they need to meet the requirements of structural strength, stiffness, and aerodynamic performance at the same time. The design of these key components is the focus of the overall aircraft design. The installation position of the tilt-ducted fan is relatively flexible. It can be installed at different positions such as the wings, canards, tail ends, or fuselage of the tilt-ducted fan aircraft according to the specific design requirements of different aircraft. The number of ducted fans is usually 2 to 6.

[0006] The complete flight phase of the tilt-ducted fan aircraft includes five phases: vertical take-off, tilt 1, level flight, tilt 2, and vertical landing. The angle formed between the axis of the ducted fan of the tilt-ducted fan aircraft and the longitudinal axis of the fuselage is defined as the tilt angle Alpha of the tilt-ducted fan aircraft. The complete flight phase of the tilt-ducted fan aircraft and the tilt change process of its ducted fan are shown in the following figure. Figure 1 As shown (taking the aircraft with tilt-ducted fan devices installed on the wings and canards as an example): (1) Stage 1 is the vertical take-off 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 tilt-ducted fan aircraft reaches the specified height, 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 with the tilt of the ducted fan. 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 tilt-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 wing generates 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, and its tilt angle Alpha changes continuously from 0° to 90°. The tilting process is opposite to that of Tilt 1 stage. (5) Stage 5 is the vertical landing stage, during which the aircraft is in multi-rotor mode, the axis of the ducted fan is 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 tilting stage is the key stage for the tilt-ducted fan aircraft to switch between multi-rotor mode and fixed-wing mode. At this time, the airflow environment and structural state of the aircraft are extremely complex. Specifically, it is manifested in: ① Uneven airflow distribution. During the tilting process, the airflow environment changes dramatically. The angle of attack of the wing and ducted fan, relative wind speed, etc. will change continuously, resulting in 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 tilting process, as the duct tilt angle changes, the aerodynamic load and ducted thrust load are also constantly changing. This multi-load superposition change effect will cause complex stress distribution and structural deformation of the structural parts.

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

[0009] At present, there have been studies that analyze the aerodynamic changes and structural changes of tilt-turn ducted fan aircraft during the tilting process. Although these single-discipline research results provide references for aircraft design to a certain extent, due to the lack of systematic consideration of the mutual influence between aerodynamics and structure (i.e., aerodynamic-structural coupling effect), the prediction accuracy of aerodynamic performance and structural performance is low, which is difficult to meet the needs of practical applications. Aerodynamic-structural coupling analysis can more accurately evaluate the aerodynamic performance and structural performance of tilt-turn ducted fan aircraft by comprehensively considering the mutual influence between aerodynamics and structure of tilt-turn ducted fan aircraft. Its core lies in comprehensively evaluating the aerodynamic and structural response behaviors of key components of tilt-turn ducted fan aircraft during flight through methods such as numerical simulation. During flight, key components will be affected by aerodynamic forces, generating aerodynamic loads such as lift and drag. At the same time, the structure of key components will deform and change stress distribution under the action of aerodynamic loads and other loads. This shape change in turn affects the flow characteristics of the airflow, thereby affecting the distribution of aerodynamic loads, and ultimately leading to further changes in 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] At present, the research on aerodynamic-structural coupling of tilt-ducted fan aircraft is mainly focused on a single flight mode, while the research on the tilting process is relatively lacking, especially without involving key components such as wings, canards, tail wings, and fuselages equipped with ducts. Although the conceptual design of the wing structure disclosed in the Chinese patent (202410621455.9) involves aerodynamic-structural coupling, as a sub-module in the overall optimization system, in order to simplify the problem in the conceptual design stage, only aerodynamic-structural coupling analysis was performed for the level flight and vertical take-off and landing stages, without involving the more complex tilting process. In addition, the research object of this patent is mainly limited to wings equipped with tilt-ducted devices, and it is difficult to expand to other key components such as fuselage and tail wings, which has certain limitations.

[0011] In contrast, the aerodynamic-structural coupling analysis methods for conventional fixed-wing aircraft wings are relatively mature, and fixed-wing aircraft wings usually only need to bear stable aerodynamic loads. However, for key components of tilt-ducted fan aircraft (such as wings with tilt-ducted wingtips), in addition to the changing aerodynamic loads during the tilting process, they also need to bear the gravity of the duct and the complex and changing thrust loads. Therefore, the related aerodynamic-structural coupling analysis methods developed for fixed-wing aircraft cannot be applied to tilt-ducted fan aircraft with complex and changing loads, and cannot effectively meet specific needs. At the same time, it is also noted that there have been related aerodynamic-structural coupling analysis studies on the more mature tilt-rotor aircraft, but all of them focus on structural flutter. During the flight of a tilt-rotor aircraft, due to its large rotor diameter, the wake generated by the rotor will directly affect the aerodynamic components such as the wing and fuselage, thereby affecting the aerodynamic performance of these aerodynamic components. The tilt-ducted fan aircraft is more complex than the tilt-rotor aircraft in terms of aerodynamic design, control system, structural coupling, manufacturing and maintenance. This complexity not only increases the difficulty of design and manufacturing, but also puts forward higher control requirements. Therefore, there are significant technical barriers to directly apply the existing tilt-rotor aircraft design concept to the design of the tilt-ducted fan aircraft, and it is not easy to achieve.

[0012] In summary, the problems existing in the prior art are: (1) Regarding the coupled analysis of aerodynamic and structural performance of tilt-ducted fan aircraft, existing studies mostly focus on a single flight mode such as level flight or vertical take-off and landing, but lack research on the tilting process.

[0013] (2) Existing aerodynamic-structural coupling analysis methods for fixed-wing aircraft are mainly aimed at stable aerodynamic load conditions and are not applicable 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.

[0014] (3) Compared with other vertical take-off and landing aircraft (such as tilt-rotor aircraft), tilt-ducted fan aircraft are more complex in terms of aerodynamic design, control system, structural coupling, manufacturing and maintenance, etc. The 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

[0015] 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 coupled analysis of aerodynamic performance and structural performance, and provide a scientific basis for the subsequent design of tilt-ducted fan aircraft.

[0016] 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: 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 duct load data at each moment in the tilting process, wherein the moment is obtained by dividing the tilting process according to the duration of the tilting process. a moment, ; Preferably, the moment is evenly divided according to the duration of the tilting process; S2: Obtain characteristic data of key components of a tilt-ducted fan aircraft at all times during the tilt 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 components, the initial aerodynamic model at the time i, the incoming flow condition at the time i, and the duct load data at the time i, the characteristic data and the converged aerodynamic model at the 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, and 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 a moment; The characteristic data include aerodynamic performance data and structural performance data; the aerodynamic performance data include but are not limited to the lift, drag, lift-to-drag ratio, and pressure coefficient of the key components; the structural performance data include but are not limited to 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.

[0017] The present invention divides the duration of the tilting process of the tilting ducted fan aircraft into several moments, obtains the aerodynamic performance data and structural performance data at each moment through aerodynamic-coupling analysis and calculation, and obtains the aerodynamic-coupling analysis results of the complete tilting process based on the characteristic data at all moments. Further, the aerodynamic-structural coupling calculation at moment i includes: S221: Based on the initial aerodynamic model at time i and the incoming flow condition 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, obtaining aerodynamic force and transferring it to a structural model of a 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, wherein 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.

[0018] Furthermore, the key components are aerodynamic components of a tilt-ducted fan aircraft equipped with a tilt-ducted fan, including but not limited to the wings, canards, tail, and fuselage of the tilt-ducted fan aircraft equipped with a tilt-ducted fan.

[0019] Furthermore, the incoming flow conditions include the angle of attack and airspeed of key components of the tilt-ducted fan aircraft.

[0020] Furthermore, the duct load data includes the duct thrust and duct weight of each duct of the key components of the tilt-ducted fan aircraft.

[0021] Furthermore, the aerodynamic solver is implemented using a computational fluid dynamics method, which meshes the aerodynamic model of key components of a tilt-ducted fan aircraft and obtains aerodynamic performance data by solving control equations on the mesh.

[0022] Furthermore, the structural solver is implemented using a 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.

[0023] Furthermore, the load transfer module transfers the aerodynamic force in the aerodynamic model to the structural model through a weight function, and the specific implementation method is as follows: 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 transmitted to the structural mesh nodes in the structural model. 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, through the weight matrix 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 of . Representation and structural model mesh nodes All relevant aerodynamic model mesh nodes The sum of the distance functions.

[0024] Furthermore, the displacement transfer module transfers the displacement in the structural model to the aerodynamic model through a weight function, and the specific implementation method is as follows: The displacement transfer module transfers the displacement data in the structural performance data, that is, the structural grid nodes in the structural model The displacement is transferred to the aerodynamic mesh nodes in the aerodynamic model On, 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 transmitted through the weight matrix W. The formula is as follows: Furthermore, the convergence condition includes: The norm of the total residual of the performance data calculated in 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, and the norm calculation formula of the total residual is as follows: in, is the total residual The norm of The total residual Quantity, It is the residual of all physical quantities of structural residual and aerodynamic residual. Structural residual refers to the node displacement and stress imbalance caused by aerodynamic force in the aircraft structure model during the tilting process of the tilt-ducted fan aircraft, which is usually used to measure the error of structural calculation. Aerodynamic residual refers to the deviation of flow field variables such as velocity and pressure caused by structural deformation in the aerodynamic model during the tilting process of the tilt-ducted fan aircraft and the actual flow conditions, which is used to measure the error of aerodynamic calculation.

[0025] The present invention also provides an aerodynamic-structural coupling analysis system for a tilting ducted fan aircraft during a tilting process, which can implement the aerodynamic-structural coupling analysis method for a tilting ducted fan aircraft during a tilting process, and comprises: The tilt process modeling module is used to generate a tilt-specific data stream of a tilt-ducted fan aircraft during the tilt process; wherein the tilt-specific data stream includes the incoming flow conditions and duct 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 the characteristic data of the 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 the time i, the incoming flow condition at the time i, and the duct load data at the time i, the characteristic data and the converged aerodynamic model at the 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, and the aerodynamic model when the iterative calculation reaches the convergence condition is the converged aerodynamic model; Repeat the above steps for times, get Characteristic data at a moment; The characteristic data include aerodynamic performance data and structural performance data; the aerodynamic performance data include lift, drag, lift-to-drag ratio, and pressure coefficient of the key components, and the structural performance data include 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 change curve of the characteristic data with time.

[0026] 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: (1) The aerodynamic-structural coupling calculation method for the tilting process of key components of a tilting ducted fan aircraft proposed in the present invention 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.

[0027] (2) Modular design of aerodynamic-structural coupling calculations: 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.

[0028] (3) The model transfer technology is used to reduce the number of convergence calculations and thus improve computational efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative labor.

[0030] Figure 1 It is a diagram of the changes of the ducted fan of a tilt-ducted fan aircraft during flight, where Alpha is the tilt angle of the ducted fan.

[0031] Figure 2 It is an analysis framework diagram of the aerodynamic-structural coupling analysis method of the tilting process of the tilting ducted fan aircraft of the present invention.

[0032] Figure 3 It is a flow chart of aerodynamic-structural coupling calculation at time x during the tilting process of the present invention.

[0033] Figure 4 2 is a diagram showing airspeed changes in an embodiment of the present invention.

[0034] Figure 5 4 is a graph showing the vertical thrust provided by the duct in an embodiment of the present invention changing with time.

[0035] Figure 6 4 is a graph showing the change of the horizontal thrust provided by the duct over time in an embodiment of the present invention.

[0036] Figure 7 Schematic diagram of the initial aerodynamic model at time 6 in an embodiment of the present invention.

[0037] Figure 8 Schematic diagram of the CSM model in an embodiment of the present invention.

[0038] Fig. 9 It is a 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.

[0039] Fig.10 It 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.

[0040] Fig.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.

[0041] Fig.12 It is a curve diagram of the maximum displacement changing with time during the tilting process in the embodiment of the present invention.

[0042] Fig.13 4 is a curve diagram showing lift-to-drag ratio changing with time during the tilting process in an embodiment of the present invention.

[0043] Fig.14 3 is a comparison chart of the number of iterations of aerodynamic-structural coupling calculation when the model transfer technology is used and not used in the embodiment of the present invention. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with examples and accompanying drawings. It should be understood that the examples are only used to illustrate the present invention, but not to limit the scope of the present invention. Without departing from the spirit and scope of the present invention, the changes and advantages that those skilled in the art can think of are all included in the present invention, and are protected by the attached claims and equivalents.

[0045] It is understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "one" cannot be understood as a limitation on the number. In the present invention, except for the names and terms that have been clearly defined by the inventor, other names and terms are common names in the art.

[0046] In order to study the changes in aerodynamic and structural performance of the tilting ducted fan aircraft under the combined effects of aerodynamics, ducted thrust and ducted gravity during the tilting process, so as to provide a scientific basis for the subsequent optimization design.

[0047] In one embodiment of the present invention, the present invention proposes an aerodynamic-structural coupling analysis method during the tilting process of a tilt-ducted fan aircraft, which is used to analyze the characteristic data of key components during the tilting process of the tilt-ducted fan aircraft. The key components are aerodynamic components equipped with a tilt-ducted duct, specifically including the wings, canards, tail wing, and fuselage of the tilt-ducted fan aircraft equipped with a tilt-ducted duct. 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: S1: construct 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 duct 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, ; S2: Obtain characteristic data of key components of a tilt-ducted fan aircraft at all times during the tilt process 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 tilt-ducted fan aircraft. Otherwise, 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 components, the initial aerodynamic model at the time i, the incoming flow condition at the time i, and the duct load data at the time i, characteristic data and a converged aerodynamic model at the time i are obtained through aerodynamic-structural coupling calculation; The aerodynamic-structural coupling calculation at time i includes: S221: Based on the initial aerodynamic model at time i and the incoming flow condition 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, obtaining aerodynamic force and transferring it to a structural model of a 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, wherein 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.

[0048] S23: Repeat steps S21 and S22 times, get Characteristic data at a moment; 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.

[0049] 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 changes during the tilting process of the tilt-ducted fan aircraft, 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 wing of the tilt-ducted fan aircraft and the direction of the incoming flow. The duct load data includes each ducted thrust (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.

[0050] 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 the tilting process, and the structural performance data characterizes the structural changes of the tilt-ducted fan aircraft during the tilting process. The aerodynamic performance data includes the lift, drag, lift-to-drag ratio, and pressure coefficient of the aircraft during the tilting process of the tilt-ducted fan aircraft, and the structural performance data includes the displacement (that is, the deformation of the structure), stress, strain, and failure factor of the aircraft during the tilting process of the tilt-ducted fan aircraft.

[0051] 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. Generally, 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.

[0052] In yet 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.

[0053] In another embodiment of the present invention, the Newton-Krylov method is used to perform aerodynamic-structural coupling calculation to obtain characteristic data at time i. Newton-Krylov is a numerical algorithm mainly used to solve nonlinear partial differential equations. The specific process is as follows: (1) Initialize an initial solution, which is an initial guess at the beginning of the solution process and includes all variables in the aerodynamic model and the structural model; (2) Calculate the total residual of the aerodynamic-structural coupling model The total residual includes structural residual and aerodynamic residual. Structural residual refers to the node displacement and stress imbalance caused by aerodynamic force in the aircraft structure model during the tilting process of the tilt-ducted fan aircraft, which is usually used to measure the error of structural calculation. Aerodynamic residual refers to the deviation of flow field variables such as velocity and pressure caused by structural deformation in the aerodynamic model during the tilting process of the tilt-ducted fan aircraft and the actual flow conditions, which is used to measure the error of aerodynamic calculation.

[0054] assumed , Represent aerodynamic force and structural deformation respectively, and the aerodynamic mesh 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: (3) Constructing a linearized system 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.

[0055] To use the fully coupled Newton-Krylov method to find a solution that satisfies the coupled residual equation Solution First, we need to provide an initial solution , and then construct the linearized system at each iteration: in is the current solution The Jacobian matrix at , is the correction amount.

[0056] (4) Solve the linearized system, that is: The state variables after solution are updated as , .

[0057] (5) Final inspection Is it less than the given convergence threshold? If the condition is met, the iteration is stopped and the solution is returned. As a solution ; Otherwise, continue iterating.

[0058] In another embodiment of the present invention, Figure 3 As shown, 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: (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 ); (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: First, the CFD model X_0 is calculated using the aerodynamic solver according to 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 force through the load transfer module, and the aerodynamic force and the duct thrust TX and duct gravity GX in the duct load data X are loaded onto the CSM model together, and the structural solver is used to calculate to obtain the structural performance data; the displacement data in the structural performance data is input into the displacement transfer module to deform the CFD model X_0 to obtain the CFD model X_1; (3) Perform two coupled solution calculations based on the CFD model X_1; (4) Repeat the above steps until the convergence condition is reached after the K+1th coupling 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 transmitted to the aerodynamic structure calculation at time X+1 as the initial aerodynamic model at time X+1, recorded as CFD model (X+1)_0. At this point, the aerodynamic-structural coupling calculation at time X is completed.

[0059] Furthermore, the CFD model (CFD, 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.

[0060] Furthermore, the CSM model (CSM, computational structural mechanics), i.e., the structural model, is used to simulate the structural response of the key components being analyzed and calculate the structural characteristics such as stress, strain, deformation, etc. of the structure under the action of aerodynamic forces. It should be noted that the CSM model always remains unchanged.

[0061] Furthermore, the aerodynamic solver calculates aerodynamic performance data based on the CFD model of key components and the incoming flow conditions. The aerodynamic performance data includes lift, drag, lift-to-drag ratio, pressure coefficient, etc. Users can use high-precision aerodynamic analysis methods to perform aerodynamic solutions according to actual conditions. The high-precision analysis method can use computational fluid dynamics (CFD) methods for high-precision analysis. By meshing the three-dimensional geometric model of the wing and applying the NS equation and RANS equation to solve the flow field, more accurate parameters can be obtained.

[0062] Furthermore, the load transfer module obtains aerodynamic force according to the pressure coefficient in the aerodynamic performance data and transfers it to the structural model of the key component; Furthermore, the structural solver analyzes the wing structure according to the aerodynamic force transmitted by the load transfer module, the duct thrust and the gravity, and obtains the structural performance data. The structural performance data includes displacement, stress, strain, failure factor, etc. The user can use a high-precision structural analysis method to solve the structure according to the actual situation. The high-precision analysis method can use the finite element method (FEM) method for high-precision analysis. The discretization method is used to divide the structure into a finite number of units, and the accurate structural performance is obtained by solving the mechanical equilibrium equations of each unit.

[0063] 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.

[0064] 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.

[0065] In another embodiment of the present invention, an aerodynamic solver uses an aerodynamic solver based on the RANS equation and the Spalart-Allmaras (SA) turbulence model, and uses the aerodynamic solver to solve the aerodynamic performance data at time i during the tilting process of the tilting ducted fan aircraft. The RANS equation describes the average flow behavior of the fluid, and the SA turbulence model provides an equation for calculating the turbulent viscosity coefficient, thereby affecting the turbulent stress term in the RANS equation.

[0066] 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: The mass conservation equation (continuity equation): The momentum conservation equation (momentum equation): 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 pulsating velocity component.

[0067] Reynolds stress Through the turbulent viscosity coefficient Expressed as: in, is the turbulent kinetic energy, is the Kronecker function, the turbulent viscosity coefficient The calculation of requires the use of turbulence models, and the SA model is one of them.

[0068] The control equation of the SA model is expressed as follows: 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 a wing or other wall). is the model constant, is a correction function based on turbulence characteristics.

[0069] Turbulent viscosity coefficient pass The calculation results are: ,in is the correction function.

[0070] In another embodiment of the present invention, the structural solver uses a solver based on the FEM method (Finite Element Method) to perform linear static analysis on the structural performance data of the tilting ducted fan aircraft at time i during the tilting process. The linear static analysis can analyze the static response of the tilting ducted fan aircraft under complex loads during the tilting process by constructing a unit stiffness matrix, assembling a global stiffness matrix, solving a displacement vector, and calculating stress and strain distribution. The specific steps of solving the structural performance data by linear static analysis are as follows: (1) Constructing the unit stiffness matrix Element stiffness matrix is the stiffness matrix of each finite element, It is expressed as follows: in, is the unit volume, is the strain-displacement matrix, is the material stiffness matrix.

[0071] (2) Assembling the global stiffness matrix Global stiffness matrix , all element stiffness matrices Assemble into a global stiffness matrix according to the node connection relationship .

[0072] (4) Constructing load vector 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.

[0073] (5) Solve for the displacement vector Displacement Vector (Displacement Vector) by solving the global equilibrium equation get, (6) Calculation of strain and stress By displacement vector The strains and stresses are further calculated.

[0074] In another embodiment of the present invention, the load transfer module and the displacement transfer module adopt MELD (matched load and displacement extrapolation method), which is a multi-point explicit load and displacement transfer method widely used in aerodynamic-structural coupling analysis. The MELD method transfers aerodynamic loads and structural displacements between the CFD model and the CSM model through a weight function. The weight function is usually defined based on geometric parameters such as distance or area to ensure accuracy and stability during the transfer process.

[0075] 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 mesh nodes, is the force on the structural grid nodes, through the weight matrix To transfer: 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 To transfer: Weight Matrix Elements Usually calculated based on distance: in, Represents aerodynamic mesh nodes To the structure grid node The distance function is usually the inverse distance square. Representation and Structure of Mesh Nodes All aerodynamic mesh nodes related The sum of the distance functions of . Represents all aerodynamic mesh nodes The index of the structure grid nodes is summed up to Related Aerodynamic Mesh Nodes Perform normalization.

[0076] In another embodiment of the present invention, the convergence condition is a crucial part of the method of the present invention, which is responsible for evaluating the accuracy of the current solution and deciding 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 the structural residual are mainly considered. The specific implementation process of the convergence judgment is as follows: (1) Calculate the total residual and find its norm. The residual norm is expressed as follows: in is the total residual, The total residual Quantity, It is the residual of the physical quantity of all structural residuals and aerodynamic residuals. The physical quantity residual of aerodynamic residuals includes lift coefficient residual, drag coefficient residual, etc. The physical quantity residual of structural residuals includes structural response such as displacement residual, etc.

[0077] (2) Compare the residual norm with the preset convergence threshold Make a comparison 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.

[0078] 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 continues, the solution is updated and the residual is recalculated.

[0079] The preset convergence threshold is set by the user according to actual engineering requirements.

[0080] (3) Determine whether the number of residual iterations reaches the maximum number of iterations If convergence has not occurred after the maximum number of iterations is reached, a warning message is output or an attempt is made to adjust the initial solution or other parameters to restart the iteration.

[0081] 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, and a wing with a tilting duct installed at the wing tip is taken as an example to analyze its aerodynamic performance data and structural mechanical performance data and their changing trends during the tilting process. 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 the moment, and the duct load data includes the duct thrust and corresponding duct gravity of each duct at the moment when the tilting ducted fan aircraft is located.

[0082] 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 maintained at 3°, and the airspeed changes as follows Figure 4 As shown; the duct 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.

[0083] The duration of the tilting process is 7 seconds, which is evenly divided into 20 moments, that is, N=20. The duration of the tilting process is obtained from flight dynamics simulation and related experiments, and the specific number of divided moments is obtained according to the required data accuracy. Take the analysis of moment 6 as an example, that is, X=6, the data of this moment is divided into two parts: Incoming flow condition 6: Angle of attack (unit: °), airspeed (Unit: m / s); Ducted load data 6: Ducted thrust (The tilt angle is 38.6°, equivalent to the vertical direction , horizontal direction ), duct gravity (direction is vertically downward); Before starting the aerodynamic-structural coupling calculation, it is necessary to use CAD software to build a 3D model of the wing, including a 3D model of the wing geometry related to aerodynamic analysis and a 3D model of the wing structure related to structural analysis. Then, the corresponding meshing and generation tools are used to generate the corresponding CFD model for aerodynamic analysis and the CSM model for structural analysis.

[0084] The aerodynamic-structural coupling calculation process at time 6 is as follows: 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 transferred to the corresponding nodes 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 duct gravity Load it onto the CSM model, then calculate the structural deformation through the structural solver, obtain the displacement of the corresponding node of the CFD grid through the displacement transfer technology, and obtain a deformed CFD model 6_1 through the dynamic mesh algorithm to complete the first coupling solution. Then calculate the new aerodynamic force through aerodynamic solution based on the 6_1 model grid. Repeat the above steps until the convergence condition is met after the fifth coupling solution, and then output the coupling calculation results at time 6. At this point, the wing aerodynamic-structural coupling calculation at time 6 is completed, the characteristic data is output, and the CFD model 6_5 is transmitted to time 7 as the initial CFD model 7_0 at time 7.

[0085] 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 time, the ks failure factor cloud map, etc. Fig. 9 is a schematic diagram of the wing surface pressure coefficient after the aerodynamic-structural coupling calculation converges at time 6. Fig.10 is a schematic diagram of the wing structure deformation after the aerodynamic-structural coupling calculation converges at time 6. Fig.11 is a schematic diagram of the KS failure factor of the wing structure after the aerodynamic-structural coupling calculation converges at time 6. Fig.12 is the curve of maximum displacement changing with time during the tilting process, Fig.13 It is a curve graph of lift-to-drag ratio changing with time during the tilting process.

[0086] Compared with the prior art that inputs from the initial CFD model 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: Fig.14As shown. Using the model transfer technology of the present invention, a total of 100 iterations at 20 moments took 1626.17 seconds; without the model transfer technology, a total of 192 iterations took 3736.72 seconds. The model transfer technology used in the present invention can reduce the number of calculation iterations by 47.9%, shorten the calculation time by 56.5%, and greatly improve the calculation efficiency.

[0087] 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 a tilt-ducted fan aircraft. The aerodynamic-structural coupling calculation method of the present invention adopts a modular design, and the aerodynamic solvers, structural solvers, load transfer modules, and displacement transfer modules of different accuracy and calculation speeds can be replaced 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.

[0088] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other 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.

[0089] The above-mentioned specific implementation methods are used to explain 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 protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. An aerodynamic-structural coupling analysis method for a tilting ducted fan aircraft during its tilting process, characterized in that: The method comprises: 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 duct load data at each moment in the tilting process, and the moment is obtained by dividing the tilting process according to the duration of the tilting process. a moment, ; S2: Obtain characteristic data of key components of a tilt-ducted fan aircraft at all times during the tilt 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 components, the initial aerodynamic model at the time i, the incoming flow condition at the time i, and the duct load data at the time i, the characteristic data and the converged aerodynamic model at the 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, and 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 a moment; The characteristic data include aerodynamic performance data and structural performance data; the aerodynamic performance data include lift, drag, lift-to-drag ratio, and pressure coefficient of the key components, and the structural performance data include 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 condition 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, obtaining aerodynamic force and transferring it to a structural model of a 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, wherein 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, characterized in that The duct load data includes the duct thrust and duct 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 by using a computational fluid dynamics method, which performs grid division on the aerodynamic model of key components of the 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 tilt-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, through the weight matrix 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 of 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, and the specific implementation method 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 transmitted 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 in 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, and the norm calculation formula of the total residual is as follows: in, is the total residual The norm of The total residual A quantity.

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 a tilt-ducted fan aircraft during the tilt process; wherein the tilt-specific data stream includes the incoming flow conditions and duct 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 the characteristic data of the 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 the time i, the incoming flow condition at the time i, and the duct load data at the time i, the characteristic data and the converged aerodynamic model at the 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, and the aerodynamic model when the iterative calculation reaches the convergence condition is the converged aerodynamic model; Repeat the above steps for times, get Characteristic data at a moment; The characteristic data include aerodynamic performance data and structural performance data; the aerodynamic performance data include lift, drag, lift-to-drag ratio, and pressure coefficient of the key components, and the structural performance data include 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 change curve of the characteristic data with time.

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