Low dynamic load structure design method based on image method

Abstract

The invention provides a low dynamic load structure design method based on an image method. The method comprises the following steps: constructing a relationship among a dynamic load modal number, a structure characteristic frequency and a convection velocity of a structure surface; rib parameters are defined; determining a structural characteristic frequency after the ribs are added, and obtaining an optimal dynamic load modal number which is effectively inhibited by structural dynamic response under the frequency; obtaining structural characteristic frequencies and optimal dynamic load modal numbers corresponding to different rib parameters; determining a change graph of the convection speed along with the rib parameters according to the relationship; and according to the convection velocity in a known application scene, substituting the convection velocity into the change diagram to determine an optional scheme of rib parameters, and obtaining a low-dynamic-load structure. According to the method, a low-dynamic-load structure with a low vibration level under the analysis frequency can be obtained, so that the flight stability of an aircraft is improved, and the service life of a local structure is prolonged.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aircraft local structure dynamic response suppression, and particularly relates to a low dynamic load structure design method based on an image method. BACKGROUND

[0002] With the development of aerospace technology, the performance and safety requirements of aircraft in complex flight environments are increasing. Due to the action of the wall turbulent boundary layer, the local structure of the aircraft will be subjected to strong dynamic load during flight, resulting in problems such as severe vibration and fatigue damage of the local structure, which seriously affects the structural safety and service life of the aircraft, and may even cause serious safety accidents. Therefore, to solve the problem of aircraft structure safety design, it is necessary to develop effective structure dynamic response suppression methods and improve the performance and safety of aircraft in complex flight environments.

[0003] Active vibration control is an important technology to improve the performance and reliability of aircraft. This method needs to monitor the dynamic response of the aircraft structure in real time, and actively apply external force combined with the control system to reduce the response. In contrast, passive control technology often uses simpler and more reliable means. Traditional methods mainly include structure reinforcement, adding damping materials, optimizing structure design, etc. By attaching specific devices or materials to the structure to absorb and dissipate vibration energy, the purpose of vibration suppression is achieved. Northeastern University's Yao Guotuan team proposed a nonlinear piezoelectric shunt damping method. Under different external excitation amplitudes and airflow speeds, the effectiveness of these circuits in vibration control was compared. Shenyang Aerospace University's Zang Jian team explored the dynamic characteristics and vibration control of the cockpit wall panel of a new energy electric aircraft. By embedding NiTi shape memory alloy (SMA) wires in the composite structure, structure vibration control was achieved.

[0004] However, existing structure dynamic response suppression research is limited to analyzing the influence of different wall dynamic load environments on structure vibration from the time-frequency perspective. Although active control technology can achieve precise control of specific frequency and direction vibrations, it has high control accuracy and significant control effect. However, due to the complexity of the system, it also brings problems of reliability and stability. In passive control methods, structure reinforcement increases the overall weight of the aircraft, reducing the maneuverability of the aircraft. Adding damping materials may have a negative impact on the mechanical properties of the structure, and the performance stability of the damping materials is difficult to guarantee in complex flight environments. Therefore, in order to solve the safety design problem of new generation aircraft, more effective and reliable structure dynamic response suppression methods must be developed to improve the performance and safety of aircraft in complex flight environments. SUMMARY

[0005] Therefore, in view of the problem that the existing dynamic response suppression method only focuses on the time-frequency characteristics of the structural dynamic response and cannot effectively reflect the coupling mechanism of the spatial modal of the flow-induced dynamic load and the structure, the main purpose of the present application is to provide a low dynamic load structure design method based on the image method, which considers the dynamic response characteristics under different matching conditions of the spatial modal of the dynamic load and the characteristic modal of the structure, calculates the contour map of the appropriate flow velocity under the optimal matching condition, and designs the structure according to the coordinates corresponding to the size of any point on the contour line, so that the low dynamic load structure with low vibration level at the analysis frequency can be obtained, thereby improving the flight stability of the aircraft and the service life of the local structure.

[0006] In order to solve the above technical problems, the present application is implemented as follows.

[0007] A low dynamic load structure design method based on the image method, comprising:

[0008] Step one, constructing the relationship between the dynamic load modal number N f , the characteristic frequency f s of the structure, and the convection velocity U c of the structure surface;

[0009] Step two, defining the rib parameters [alpha, beta] of the rib structure: defining the mass ratio alpha of the added rib according to the relationship between the rib mass and the original structure mass; defining the width-thickness ratio beta of the added rib according to the relationship between the rib width and the thickness;

[0010] Step three, selecting a rib parameter [alpha, beta], determining the characteristic frequency f s (alpha, beta) of the structure after adding the corresponding rib, and the optimal dynamic load modal number s (alpha, beta) under which the dynamic response of the structure is effectively suppressed;

[0011] Selecting different rib parameters [alpha, beta] within a certain range to obtain the first variation law of the characteristic frequency f s (alpha, beta) of the structure with the rib parameters [alpha, beta], and the second variation law of the optimal dynamic load modal number with the rib parameters [alpha, beta];

[0012] Step four, substituting the characteristic frequency f s (alpha, beta) of the structure and the optimal dynamic load modal number into the relationship constructed in step one to obtain the variation graph of the convection velocity U c with the rib parameters [alpha, beta];

[0013] Step five, determining the optional scheme of the rib parameters [alpha, beta] according to the convection velocity under the known application scenario, and obtaining the low dynamic load structure.

[0014] Preferably, in step 1, the number of dynamic load modes N f , the structural characteristic frequency f s and the convection velocity U c are related as follows:

[0015]

[0016] wherein, l is the structural characteristic length.

[0017] Preferably, in step 3, the selection of a string parameter [a, b] to determine the structural characteristic frequency f s (a, b) after adding the string, and the preferred dynamic load mode number s (a, b) at which the structural dynamic response is effectively suppressed at the structural characteristic frequency f (a, b) specifically includes:

[0018] Selecting a string parameter [a, b], and using the finite element method to calculate the structural characteristic frequency f s (a, b) after adding the string expressed by [a, b];

[0019] Changing the dynamic load mode number N f at the structural characteristic frequency f s (a, b), and using simulation to obtain the curve of the structural dynamic response with the dynamic load mode number N f ;

[0020] The dynamic load mode number corresponding to the first minimum point of the structural dynamic response is recorded as the preferred dynamic load mode number This indicates that the dynamic load mode number reaches this value under the current string parameter [a, b] and a certain convection velocity U c , and the structural dynamic response is effectively suppressed.

[0021] Preferably, in step 3, the selection of different string parameters [a, b] within a certain range to obtain the first variation of the structural characteristic frequency f s (a, b) with the string parameter [a, b], and the second variation of the preferred dynamic load mode number with the string parameter [a, b] is as follows:

[0022] Selecting different string parameters [a, b] within a certain range, calculating the corresponding structural characteristic frequency f s (a, b) and the preferred dynamic load mode number

[0023] According to the structural characteristic frequency f s(α,β), plot the structure characteristic frequency f s (α,β) in the first cloud chart in the α-β plane;

[0024] According to the preferred dynamic load modal number corresponding to the rib parameter [α,β] Plot the preferred dynamic load modal number The second cloud chart in the α-β plane.

[0025] Preferably, the fourth step is: according to the structure characteristic frequency f s (α,β) and the preferred dynamic load modal number Substitute the relationship constructed in the first step, plot the convection velocity U c The third cloud chart in the α-β plane.

[0026] Preferably, the fifth step is: according to the convection velocity under the known application scene Make in the third cloud chart The corresponding contour line, the series of rib parameters [α,β] corresponding to the contour line is the optional rib structure.

[0027] Preferably, when the rib structure is determined according to the contour line, the actual mass ratio α * Is determined first, and then the actual mass ratio α * Corresponding to the width-thickness ratio β * , the actual rib width and thickness are determined according to β * .

[0028] Preferably, in the curve of the change of the structure dynamic response with the dynamic load modal number N f , the structure dynamic response is expressed by the vibration average speed.

[0029] Preferably, characterized in that, the structure is a high-speed aircraft structure.

[0030] Preferably, the l is the length of the structure in the flow direction.

[0031] Beneficial effects:

[0032] (1) The low dynamic load structure design method disclosed in the application can effectively clarify the vibration rule and mechanism caused by the dynamic load space correlation, suppress the aircraft structure dynamic response, and prolong the service life of the structure.

[0033] (2) The application discloses a low-dynamic-load structure design method based on an image method, and is suitable for suppressing dynamic response of a local structure of an aircraft under the action of high-speed airflow. Non-dimensional parameters are used to describe the shape and size of a rib, characteristic frequencies and dynamic response minimum values of a ribbed plate under different combinations of rib mass ratios and width-thickness ratios are calculated, and a convection velocity contour map is generated, so that all low-dynamic-load structure design sizes can be found at one time, and the method is simpler and more effective than traditional flow control and structure design methods. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a schematic diagram of defining the dynamic load modal number.

[0035] Figure 2 is a schematic diagram of the variation of dynamic response with the dynamic load modal number in different ribbed structure examples.

[0036] Figure 3 is a characteristic frequency cloud diagram of the ribbed structure.

[0037] Figure 4 is a dynamic load modal number cloud diagram corresponding to the minimum value of the dynamic response.

[0038] Figure 5 is a convection velocity contour map corresponding to the minimum value of the structure dynamic response.

[0039] Figure 6 is a dynamic response curve diagram of the initial structure and the low-dynamic-load structure

[0040] Figure 7 is a flow chart of the low-dynamic-load structure design method based on the image method. DETAILED DESCRIPTION

[0041] The specific embodiments of the application are further described below in combination with the drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the application, and cannot be used to limit the protection scope of the application.

[0042] Example 1

[0043] The embodiment provides a low-dynamic-load structure design method based on an image method, as shown in the figure, including the following steps: Figure 7

[0044] Step 1, flow parameter and relationship definition.

[0045] This step constructs the relationship of the dynamic load modal number N f , the structure characteristic frequency f s and the convection velocity U c of the structure surface.

[0046] ​Specifically, the dynamic load modal wavelength λ c is defined by the convection velocity U f and the analysis frequency f f The dynamic load modal number N f is defined by the ratio of the structural characteristic length l and the dynamic load modal wavelength λ f When the structural modal is fixed, the dynamic load modal number N f can be adjusted by changing the dynamic load modal wavelength λ f , so as to change the matching relationship between the dynamic load modal and the structural modal, thereby affecting the structural dynamic response and suppressing the structural dynamic response at the analysis frequency.

[0047] The specific method for selecting the characteristic parameters is as follows:

[0048] First, the dynamic load modal wavelength λ f is determined by the convection velocity (disturbance migration velocity) U c in the turbulent boundary layer and the analysis frequency f f , and the expression is as follows:

[0049]

[0050] The dynamic load modal number N f is determined by the ratio of the structural characteristic length l and the dynamic load modal wavelength λ f , and the calculation formula is as follows:

[0051]

[0052] According to formula (1) and formula (2), the dynamic load modal number N f can be further expressed in the form of formula (3):

[0053]

[0054] Step 2: Definition of the rib parameter:

[0055] This step defines the rib parameter [α, β] representing the rib structure.

[0056] Specifically, in order to suppress the initial structural dynamic response, the rib is used to adjust the characteristic frequency and the dynamic load distribution of the structure. In order to obtain a more universal rule, two dimensionless parameters describing the shape and size of the rib are defined: the mass ratio α of the added rib is defined according to the relationship between the mass of the rib and the mass of the original structure; the width-thickness ratio β of the rib is defined according to the relationship between the width and the thickness of the rib, which facilitates the introduction of the rib parameter into the subsequent step of structural dynamic response calculation.

[0057] The specific method for selecting the structural parameter is as follows:

[0058] The mass ratio α of the rib is determined by the mass wb and the initial structure mass w0, which is expressed as:

[0059]

[0060] The length of the rib is the same as the width of the initial structure and is determined according to the shape of the initial structure. The width-thickness ratio β of the rib is determined by the ratio of the width σ and the thickness δ of the rib, which is expressed as:

[0061]

[0062] Step three, calculation of key parameters:

[0063] Select a rib parameter [α, β], which can be determined by any rib mass ratio α and width-thickness ratio β. Determine the structural characteristic frequency f s (α, β) of the structure after adding the rib, and the preferred number of dynamic load modes under which the structural dynamic response is effectively suppressed at the structural characteristic frequency f s (α, β). Select different rib parameters [α, β] within a certain range to obtain the first change rule of the structural characteristic frequency f s (α, β) with the rib parameters [α, β], and the second change rule of the preferred number of dynamic load modes with the rib parameters [α, β].

[0064] In order to facilitate the understanding of the relationship between the parameters, the change rule can be made in the form of a cloud chart. Then this step specifically includes the following sub-steps:

[0065] Step 31: Design a ribbed structure according to any rib parameter [α, β], and calculate the structural characteristic frequency f s (α, β) of the structure to be optimized after adding the rib [α, β] structure by using the finite element method.

[0066] Step 32: Change the number of dynamic load modes N f at the structural characteristic frequency f s (α, β) determined in step 31. The change rule of the structural dynamic response with the number of dynamic load modes can be obtained by simulation. The change rule is shown in Figure 2 . The structural dynamic response is characterized by the average vibration speed. The figure is the change curve of the average vibration speed with N f in different examples.

[0067] Step 33: Due to the change of the matching relationship between the structural mode and the dynamic load mode, the size of the structural dynamic response changes periodically with N f , showing a wave crest-valley change, and the preferred number of dynamic load modes is determined as Figure 2 ​The number of dynamic load modes corresponding to the first minimum point of the vibration velocity is denoted as the preferred number of dynamic load modes. Should This indicates that when the number of dynamic load modes reaches this value under the current stiffener parameters [α,β], the dynamic response of the structure is effectively suppressed, resulting in a low dynamic load structure.

[0068] Step 34: Select different stiffener parameters [α,β] within the set range and calculate the corresponding structural characteristic frequency f. s (α,β) and preferred dynamic load mode numbers Based on the structural characteristic frequency f corresponding to the rib parameters [α,β] s (α,β), plot the structural characteristic frequencies f s The first contour plot of (α,β) on the α-β plane. Based on the preferred dynamic load mode number corresponding to the stiffener parameters [α,β]. Plot the optimal dynamic load mode number The second contour map on the α-β plane.

[0069] like Figure 3 and Figure 4 As shown, with the rib width-to-thickness ratio β as the abscissa and the rib mass ratio α as the ordinate, different combinations of their values ​​form several grid points on the α-β plane. The structural characteristic frequency f corresponding to each grid point [α,β] is calculated. s (α,β) and the number of dynamic load modes when the dynamic response reaches its minimum value The characteristic frequencies of the structure and the number of dynamic load modes can be plotted on the α-β plane.

[0070] Step 4: Plotting the convection velocity contour map: The structural characteristic frequency f... s (α,β) and preferred dynamic load mode numbers Substituting into the following formula (6), the convection velocity U is obtained. c A graph showing the variation of stiffener parameters [α, β].

[0071] In this step, the structural characteristic frequency f calculated in step three will be used. s (α,β) and the number of dynamic load modes when the dynamic response reaches its minimum value Substitute into equation (3) and rewrite equation (3):

[0072]

[0073] This formula represents the convection velocity U c Under certain conditions, by designing a stiffened structure according to the stiffener mass ratio α and width-to-thickness ratio β, the structural characteristic frequency can reach f. s (α,β), according to the definition of dynamic load modal number, makes the dynamic load modal number equal to the expected value. Thus, the structural dynamic response reaches a minimum. Conversely, U c (α,β) represents the convection velocity that should be had when the dynamic response reaches a minimum under the current stiffening size (α,β).

[0074] This step adopts the structural characteristic frequency f s (α,β) and the preferred dynamic load modal number The corresponding convection velocity U c is calculated. c Using the convection velocity U c corresponding to all [α,β], a third cloud chart of the convection velocity U Figure 5 on the α-β plane can be drawn. Figure 5 The grid Ma in the third cloud chart represents the Mach number of the convection velocity U c .

[0075] Step five, low dynamic load structure size selection: according to the convection velocity under the known application scenario, the change chart is substituted to determine the selectable scheme of the rib parameters [α,β].

[0076] The local structure surface convection velocity under the actual situation is determined. The contour line of the third cloud chart is found, and a series of rib parameters [α,β] corresponding to the contour line is the selectable stiffened structure. An arbitrary point on the contour line is taken, and the rib mass ratio α and the width-thickness ratio β corresponding to the coordinates of the point are used to design the stiffened structure, so that the low dynamic load structure with a lower vibration level under the characteristic frequency can be obtained.

[0077] When the stiffened structure is designed according to the contour line, the actual stiffening mass of the general structure is given data, so the ratio of the actual stiffening mass to the original structure mass is determined and is recorded as the actual mass ratio α * , then the width-thickness ratio β * corresponding to the actual mass ratio α * is determined from the contour line, the width and thickness of the actual stiffening are determined according to β * , and thus the low dynamic load structure with a lower vibration level under the structural characteristic frequency can be obtained.

[0078] Example two

[0079] This embodiment applies the present application to the structural design of a high-speed aircraft.

[0080] The surface structure and mechanical components of high-speed vehicles often produce severe structural vibration due to dynamic loads generated by turbulent boundary layers, which can cause problems such as reduced instrument performance and shortened structural service life. Therefore, it is crucial to assess the flow-induced vibration level of key components and develop effective methods to mitigate structural vibration. This example uses a flat plate structure as an example to change the structural characteristic frequency and dynamic load mode number through ribbing means, and to obtain all design size combinations of low dynamic load structure by drawing the contour map of convective velocity.

[0081] The second embodiment discloses a low dynamic load structure design method based on image method, the specific implementation steps are as follows:

[0082] Step 1, definition of flow parameters.

[0083] In this embodiment, the convective velocity U c = 1.2Ma is taken as an example, and the structural characteristic length is the streamwise length l of the flat plate = 0.3m. Different dynamic load space modes are shown in Figure 1 , the dynamic load mode number represents the number of complete wavelengths of the dynamic load acting on the structural characteristic length, which is related to the analysis frequency at a certain convective velocity.

[0084] Step 2, definition of rib parameters: on the basis of the initial flat plate structure, ribbing treatment is carried out, in order to describe the shape and size of the rib, two dimensionless parameters are defined: the mass ratio of the added rib is defined according to the relationship between the mass of the rib and the mass of the original structure α; the width-thickness ratio of the rib is defined according to the relationship between the width and the thickness of the rib β.

[0085] In this embodiment, the initial structure takes a simply supported flat plate structure as an example, and the length, width and thickness of the flat plate are a×b×h = 0.3m×0.09m×0.003m. The initial flat plate structure and the added rib are both made of carbon fiber material, the rib direction is along the width direction of the flat plate, and the position is in the middle of the flat plate. The mass ratio α and the width-thickness ratio β of the rib can be calculated by formulas (4) and (5).

[0086] Step 3, calculation of key parameters: under different combinations of rib mass ratio and width-thickness ratio, the characteristic frequency f s (α,β) of the ribbed structure can be calculated by the finite element method. Then, taking the frequency f s (α,β) as the analysis frequency, the change curve of the structural dynamic response with the dynamic load space wave number can be obtained by changing the convective velocity, so as to obtain the dynamic load mode number

[0087] In the range of rib mass ratio 1%≤α≤4% and width-thickness ratio 1≤β≤4, the cloud maps of the structural characteristic frequency and the dynamic load mode number corresponding to the minimum value of the dynamic response in the α-β plane are shown in Figure 3 andFigure 4 The greater the mass of the rib and the smaller the width-thickness ratio, the greater the structural characteristic frequency and the smaller the preferred dynamic load modal number.

[0088] Step four, convection velocity cloud map drawing: the parameters of each grid point are substituted into formula (6) to calculate the convection velocity of the current structure with the lowest dynamic response size. Figure 3 and Figure 4 The parameters of each grid point are substituted into formula (6) to calculate the convection velocity of the current structure with the lowest dynamic response size.

[0089] According to the calculated data of each grid point, the convection velocity U c The cloud map on the α-β plane is drawn, and a series of convection velocity value contours are made, as shown in Figure 5 The greater the mass of the rib and the smaller the width-thickness ratio, the greater the convection velocity.

[0090] Step five, low dynamic load structure size selection: in this embodiment, it is assumed that the actual convection velocity is 1.2Ma, and according to the convection velocity cloud map obtained in step four, the corresponding contour can be found, see the line corresponding to 1.2 in the figure. According to the requirement of the actual rib mass, for example, the rib mass should not exceed 2%, a point (α=2%, β=2.5) can be taken on the contour. According to the size of the rib structure, a low dynamic load structure with lower vibration level at the characteristic frequency can be obtained.

[0091] Figure 6 The dynamic response curves of the initial flat plate structure and the designed low dynamic load structure near the first order frequency are shown in the figure. Through the design of the low dynamic load structure, the dynamic response size is effectively suppressed.

[0092] The conventional aircraft dynamic response suppression method only studies from the time-frequency domain, without considering the suppression effect of the spatial wave number of the dynamic load on the structure dynamic response. Increasing the damping material may have an adverse effect on the mechanical properties of the structure; using structure reinforcement and other methods often need to increase a large mass, Figure 6 The dynamic response sizes of the structures obtained by using the uniform thickening method and the low dynamic load structure design method are compared when the same 2% mass is increased. The vibration suppression effect of the conventional method is obviously poorer. The low dynamic load structure design method based on the image method proposed in the present application not only considers the time-frequency characteristics of the structure, but also suppresses the dynamic response size by changing the matching relationship between the dynamic load modal and the structure modal. Without causing a large increase in the mass of the aircraft, the structural response is significantly reduced, which provides certain theoretical support for the structural safety and fine design of the aircraft.

[0093] The above specific embodiments only describe the design principles of the present application, and the shapes and names of the components in the description can be different and are not limited. Therefore, those skilled in the art of the present application can modify or equivalently replace the technical solutions described in the foregoing embodiments; and these modifications and replacements do not deviate from the purpose and technical solutions of the present application, and should all belong to the protection scope of the present application.

Claims

1. A low dynamic load structure design method based on an image method, characterized by, Comprising: Step one, construct the dynamic load modal number N f , structural characteristic frequency f s , and the relationship between the convection velocity U c of the structure surface; Step two, defining the parameters of the rib structure [α,β]: according to the relationship between the rib mass and the original structure mass, the mass ratio of the added rib is defined as α; according to the relationship between the rib width and the thickness, the width-thickness ratio of the added rib is defined as β; Step three, select a strip parameter [α,β] to determine the structural characteristic frequency f after adding the corresponding strip s (α,β), and the preferred dynamic load modal number of the structure dynamic response effectively suppressed at the structural characteristic frequency f s (α,β) Selecting different strip parameters [α,β] in a set range, obtaining structural characteristic frequency f s The first change rule of (α,β) with the strip parameters [α,β], and the preferred dynamic load modal number The second change rule of (α,β) with the strip parameters [α,β] Step four, the structural feature frequency f s (α,β) and preferred dynamic load modal number Substitute the relationship constructed in step one, obtain the convection velocity U c The figure of the change of the rib parameter [α,β]; Step five, the convection velocity under the known application scenario The optional scheme of substituting the change diagram to determine the strip parameters [a, b] is obtained.

2. The method of claim 1, wherein, In step one, the number of constructed dynamic load modal N f , structural characteristic frequency f s and the relationship with the convection velocity U c is: In the formula, l is the characteristic length of the structure.

3. The method of claim 1, wherein, In step three, the selection of one strip parameter [α,β] determines the structural characteristic frequency f s (α,β) of the structure after the strip is added s (α,β) and the preferred dynamic load modal number of the structure dynamic response effectively suppressed at the structural characteristic frequency f Specifically includes: selecting a strip parameter [α,β], calculating the structural characteristic frequency f of the structure after adding the strip expressed by [α,β] by using the finite element method s (α,β); At the structural characteristic frequency f s , the dynamic load modal number N f is changed under (α, β), and the simulation is used to obtain the curve of the structural dynamic response with the dynamic load modal number N f ​ The dynamic load modal number corresponding to the first minimum point of the structural dynamic response is recorded as the optimal dynamic load modal number The represents the current rib parameter [α, β] and a certain convection velocity U c The dynamic load modal number reaches the value, and the structural dynamic response is effectively suppressed.

4. The method of claim 1, wherein, In step three, the different strip parameters [α,β] are selected within a set range to obtain the structural characteristic frequency f s The first variation law of (α,β) with the strip parameters [α,β] and the preferred dynamic load modal number The second variation law of (α,β) with the strip parameters [α,β] is: Select different strip parameters [α,β] in a set range, calculate the corresponding structural characteristic frequency f s (α,β) and preferred dynamic load modal number According to the structural characteristic frequency f s (α,β) of the strip parameters [α,β] s (α,β) in the α-β plane; Preferred dynamic load mode numbers corresponding to the strip parameters [a, b] Plotting preferred dynamic load mode numbers Second cloud plot on the a-b plane.

5. The method of claim 1, wherein, Step four is to determine the structural feature frequency f s (α,β) and preferably dynamic load modal numbers Substitute the relationship constructed in step one with the convection velocity U c Third cloud map on the α-β plane.

6. The method of claim 5, wherein, The fifth step is to obtain the convection velocity under the known application scenario In the third cloud picture The corresponding contour line, and the series of rib parameters [α, β] corresponding to the contour line are the optional rib structures.

7. The method of claim 6, wherein, In determining the stiffened structure according to the contour line, the actual mass ratio a is determined first * , and the actual mass ratio a is determined from the contour line * . The corresponding width-thickness ratio b * is determined according to b * , and the actual width and thickness of the stiffener are determined.

8. The method of claim 3, wherein, The dynamic response of the structure follows the number of dynamic load modes N f In the variation curve, the structural dynamic response is represented by the average vibration velocity.

9. The method of any of claims 1-8, wherein, The structure is a high-speed aircraft structure.

10. The method of claim 3, wherein, The l is the length of the structure in the flow direction.

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