Low dynamic load structure design method based on multi-step iteration

Abstract

The invention provides a low dynamic load structure design method based on multi-step iteration. According to the method, the influence of a matching relation between a dynamic load mode and a structural characteristic mode on structural dynamic response is considered, a reinforced structure with the minimum structural dynamic response and the convergent dynamic load mode is searched through an iteration process, and the structure is a low-dynamic-load structure. The low dynamic load structure with low speed response under the analysis frequency is obtained on the premise that the buffeting frequency is not avoided and the aerodynamic configuration is not changed. The method is particularly suitable for dynamic response control of the local structure of the aircraft under the action of high-speed airflow.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aircraft, and particularly relates to a low dynamic load structure design method based on multi-step iteration. BACKGROUND

[0002] With the continuous progress of aerospace industry, the requirements for aircraft flight performance indicators are increasingly improved. High speed and high maneuverability often become important design indicators of new generation aircraft, which makes the dynamic load environment faced by the aircraft in flight increasingly severe, thereby posing a severe challenge to the safe operation of the aircraft: the interaction between high-speed airflow and aircraft structure not only produces a large amount of aerodynamic noise, but also causes the aircraft structure components to vibrate, and excessive structural vibration may directly cause the aircraft structure to be damaged. The severe dynamic load environment and the structural dynamic response induced thereby pose a great threat to the structural safety and stable operation of new generation aircraft, and the structural dynamic response suppression of high-speed aircraft is an important technical problem that must be considered in aircraft design and development.

[0003] The commonly used dynamic response suppression methods can be divided into two categories: structure design and flow control. There are many methods for achieving buffeting suppression through structure design, such as the commonly used stiffening method, which changes the structural stiffness by thickening the local structure, and at the same time increases the structural natural frequency, so as to avoid resonance with the dynamic load frequency. Memory alloy can also be added to make damping elements, which will deform elastically when the structure vibrates, and the vibration energy will be converted into mechanical energy loss inside the alloy, thereby effectively attenuating the vibration. Flow control is a technology for suppressing structural vibration response by changing the flow field distribution and the size of the dynamic load acting on the structure surface, which can be further divided into active flow control and passive flow control according to whether external energy is introduced. Active flow control adjusts the flow field in real time through external energy input, and has flexible response and strong adaptability, which is suitable for dynamic changing flow field environment. Passive flow control has the characteristics of not relying on external energy input, and adjusts the flow field by optimizing the structure shape or adding fixed devices to reduce the dynamic load size borne by the structure.

[0004] However, the existing structure dynamic response suppression technology, whether through flow control or structure design, is to control the single dynamic load size or structure stiffness, so as to reduce the structure dynamic response. For the flow control method, the installation of the flow control device on the aircraft will affect the original aerodynamic performance of the aircraft, thereby limiting the suppression effect of the dynamic load size. And for the structure design method, since the dynamic load faced by the high-speed aircraft generally has a wide frequency range, it is difficult to avoid the buffeting frequency by using structure reinforcement. Therefore, the existing structure dynamic response suppression method is often limited by practical problems and cannot effectively meet the engineering requirements. In order to solve the serious dynamic response problem faced by the new generation of high-speed aircraft, a more reliable structure dynamic response suppression method must be developed to provide certain technical support for ensuring the future aircraft structure safety design and improving the structure service life. SUMMARY

[0005] Therefore, the present application provides a low dynamic load structure design method based on multi-step iteration, which considers the influence of the matching relationship between the dynamic load mode and the structure characteristic mode on the structure dynamic response in the process of suppressing the local structure dynamic response of the high-speed aircraft, and obtains a low dynamic load structure with lower speed response at the analysis frequency without avoiding the buffeting frequency and changing the aerodynamic shape. The present application is especially suitable for controlling the dynamic response of the local structure of the aircraft under the action of high-speed airflow.

[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 multi-step iteration, comprising: Step one, defining the rib parameters representing the rib structure , ]: defining the mass ratio of the added rib according to the relationship between the rib mass and the original structure mass ; defining the width-thickness ratio of the added rib according to the relationship between the rib width and the thickness ; Step two, constructing the relationship between the dynamic load mode number , the structure characteristic frequency and the convection velocity of the structure surface ; Step three, starting the iterative design, for the original structure without added rib, determining the structure characteristic frequency by simulation, and at the structure characteristic frequency , the dynamic load mode number at which the structure dynamic response is effectively suppressed is recorded as ; assigning to as the non-optimal dynamic load mode number which has not converged; Step four, under the convection velocity With the known , the structural characteristic frequency of the structure is obtained by substituting the relationship in step two ; with the known mass ratio of the rib , the rib width-thickness ratio is adjusted so that the structural characteristic frequency of the ribbed structure is close to , and the rib width-thickness ratio is recorded as ; and , are taken as the current rib structure parameters; Step five, for the structure with the added rib , , the structural characteristic frequency is determined by simulation, and the dynamic load mode number at which the dynamic response of the structure is effectively suppressed is recorded as ; Step six, it is judged whether is less than or equal to the set convergence residual , if not, the is taken as the of the next iteration, steps four to six are repeated for multiple iterations until is less than the convergence residual , and the iteration is completed, and the structure designed according to the current , is the low dynamic load structure.

[0008] Preferably, in step one, the rib parameters , are:

[0009] In the formula, is the mass of the rib, is the mass of the original structure without the rib, is the width of the rib, is the thickness of the rib.

[0010] Preferably, in step two, the relationship between the constructed dynamic load mode number , the structural characteristic frequency and the convection velocity of the structure surface is:

[0011] In the formula, is the characteristic length of the structure.

[0012] Preferably, the is the length of the structure in the flow direction.​

[0013] Preferably, in the step three and step five, for a structure, the structure characteristic frequency is determined by simulation, and the dynamic load modal number under which the dynamic response of the structure is effectively suppressed at the structure characteristic frequency is: For the current structure, the structure characteristic frequency is calculated by using the finite element method; the dynamic load modal number is changed at the calculated structure characteristic frequency, and the curve of the structure dynamic response with the dynamic load modal number is obtained by simulation; The dynamic load modal number corresponding to the first minimum point of the structure dynamic response in the curve is the dynamic load modal number under which the dynamic response of the structure is effectively suppressed.

[0014] Preferably, in the curve of the structure dynamic response with the dynamic load modal number, the structure dynamic response is represented by the vibration average speed.

[0015] The application further provides an electronic device, comprising a processor and a memory, the memory stores programs or instructions executable on the processor, and the programs or instructions are executed by the processor to realize the steps of any one of the low dynamic load structure design methods based on multi-step iteration.

[0016] The application further provides a readable storage medium, which stores programs or instructions, and the programs or instructions are executed by the processor to realize the steps of any one of the low dynamic load structure design methods based on multi-step iteration.

[0017] Advantages: (1) The low dynamic load structure design method based on multi-step iteration disclosed in the application defines the structure parameters, dimensionless the shape size of the designed structure, which is convenient for subsequent calculation; defines the flow parameters, describes the modal distribution of the dynamic load in the flow direction, and obtains the structure vibration response results under different spatial wave numbers by simulation using the finite element method; optimizes the dynamic load spatial wave number corresponding to the minimum value of the structure vibration response under different matching relationships between the dynamic load modal and the structure modal ; according to the relationship between the dynamic load modal number and the analysis frequency, obtains the expected dynamic load wave number under the structure characteristic frequency , adjusts the rib mass ratio and the width-thickness ratio to make the structure characteristic frequency reach the value; through multiple cyclic iterations, the calculation accuracy of the dynamic load modal number gradually converges, and finally the optimal rib mass and width-thickness ratio are obtained, which fully reflects the influence of the matching relationship between the dynamic load modal and the structure modal on the structure vibration, suppresses the structure dynamic response without changing the aerodynamic shape of the aircraft structure, and improves the dynamic strength of the aircraft structure.

[0018] (2) The low dynamic load structure design method based on multi-step iteration disclosed by the application is especially suitable for vibration response control of a local structure of an aircraft under the action of high-speed airflow, improves the dynamic strength of the aircraft structure, and is simpler and more effective than traditional flow control and structure design methods. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic diagram of a structure stiffening method.

[0020] Figure 2 is a dynamic load modal distribution under different frequencies.

[0021] Figure 3 is a curve graph of the influence of spatial wave numbers on structure dynamic response.

[0022] Figure 4 is a dynamic response curve graph of a designed structure under a first-order frequency.

[0023] Figure 5 is a flow chart of the low dynamic load structure design method based on multi-step iteration disclosed by the application.

[0024] Figure 6 is a schematic diagram of the iteration process of the application.

[0025] Figure 7 is a schematic diagram of an electronic device for executing the low dynamic load structure design method based on multi-step iteration of the application. DETAILED DESCRIPTION

[0026] The existing aircraft dynamic response suppression is often adjusted by the flow control and structure design methods to adjust the flow field distribution and improve the structure stiffness, which can reduce the structure surface dynamic load strength and the structure response to a certain extent. However, due to the limitation of the original aerodynamic performance of the aircraft and the wide frequency characteristics of the dynamic load, these methods also have obvious constraints and deficiencies.

[0027] Therefore, the application provides a low dynamic load structure design method based on multi-step iteration, the basic idea of which is that the influence of the matching relationship between the dynamic load modal and the structure characteristic modal on the structure dynamic response is considered, and through an iteration process, a stiffened structure with minimum structure dynamic response and convergent dynamic load modal is found, which is the low dynamic load structure. The low dynamic load structure with low speed response under the analysis frequency is obtained under the premise of not avoiding the buffeting frequency and not changing the aerodynamic shape. The application is especially suitable for dynamic response response control of a local structure of an aircraft under the action of high-speed airflow.

[0028] The application will be described in detail below with reference to the drawings and examples.

[0029] Example One This example provides a low dynamic load structure design method based on multi-step iteration, as shown inFigure 6 The method comprises the following steps: Step 1: definition of the parameters of the rib: This step defines the rib parameters representing the rib structure , .

[0030] Specifically, the mass ratio of the rib is defined according to the relationship between the mass of the rib and the mass of the original structure , the width-thickness ratio of the rib is defined according to the relationship between the width and the thickness of the rib , and the structure parameters are defined to non-dimensionalize the shape and size of the rib, so as to facilitate the subsequent steps of bringing the structure parameters into the calculation of the dynamic response of the structure.

[0031] The specific method for selecting and defining the structure parameters is as follows: The mass ratio of the rib is determined by the ratio of the mass of the rib to the mass of the original structure , and the expression is: (1) The length of the rib is the same as the width of the original structure, which is determined according to the shape of the original structure. The width-thickness ratio of the rib is determined by the ratio of the width to the thickness of the rib, and the expression is: (2) Step 2: definition of flow parameters and relationships: This step establishes the relationship between the dynamic load modal number , the characteristic frequency of the structure , and the convection velocity of the structure surface .

[0032] Specifically, the dynamic load modal wavelength is defined according to the convection velocity f in the turbulent boundary layer of the wall and the analysis frequency , and the dynamic load modal number is defined according to the comparison relationship between the wavelength and the characteristic length of the structure , so as to facilitate the subsequent steps 2 to 4 of bringing the dynamic load modal number into the calculation of the dynamic response of the structure, and obtaining the dynamic response law of the structure under different matching conditions.

[0033] The specific method for selecting and defining the characteristic parameters is as follows: The dynamic load modal characteristic number acting on the structure is determined by the wavelength and the length of the model along the flow direction. The dynamic load wavelength is determined by the disturbance migration velocity in the turbulent boundary layer and the analysis frequency f The expression is: (3) The dynamic load modal number is determined by the ratio of the structural characteristic length and the dynamic load wavelength The calculation formula is:

[0034] According to the above formula, the dynamic load modal number can be further expressed in the form of formula (4): (4) Step three, start the iterative design, for the original structure without rib strips, determine the structural characteristic frequency by simulation, and at the structural characteristic frequency , the dynamic load modal number under which the structural dynamic response is effectively suppressed is denoted as ; Assign to as the non-optimal dynamic load modal number that has not converged.

[0035] In this step, the following sub-steps are included: Step 31: For the original structure without rib strips, calculate the structural characteristic frequency using the finite element method.

[0036] Step 32: At the structural characteristic frequency , change the dynamic load modal number, and obtain the curve of the structural dynamic response with the change of the dynamic load modal number by simulation, as shown in Figure 3 . The structural dynamic response is represented by the average vibration velocity V (Velocity).

[0037] When calculating the average vibration velocity V, first calculate the structural buffeting response power spectral density based on the finite element method, which is represented by the function: (5) Where, is the structural displacement power spectral density, is the structural modal matrix, is the transfer function, represents the generalized force matrix, is the analysis angular frequency. Then the average vibration velocity V can be calculated using the structural displacement power spectral density .

[0038] Step 33: Analyze the dynamic load modal number acting on the structure under different structural modes The influence on the structure response. Due to the change of the matching relationship between the structure modal and the dynamic load modal, the size of the structure dynamic response (V) changes with the dynamic load modal number The change presents the periodic variation of wave crest-wave trough, as Figure 2 The first minimum point of the structure dynamic response corresponds to the dynamic load modal number, which is recorded as . The indicates that when the dynamic load modal number reaches this value, the structure dynamic response is effectively suppressed, and a low dynamic load structure is obtained. However, in general, the original structure is not a low dynamic load structure, and needs to be reinforced, and after reinforcement, the change rule of the dynamic response with the dynamic load modal number changes, so is not optimal. Therefore, it is recorded as old data, that is, the value of is assigned to , as a non-optimal dynamic load modal number that does not converge.

[0039] Step four, under the condition that the convection velocity is known, substitute into equation (4) to calculate the characteristic frequency of the structure, and assign to ; according to the actual demand, the maximum rib mass that can be increased is specified, so as to obtain the mass ratio of the rib . Under the condition that the mass ratio is determined, by adjusting the width-thickness ratio of the rib, the characteristic frequency of the reinforced structure is close to , and the width-thickness ratio of the rib at this time is recorded as . Take , as the current rib structure.

[0040] Step five, for the reinforced structure , obtained in the last step, determine the structure characteristic frequency by simulation, and the dynamic load modal number at which the structure dynamic response is effectively suppressed under the structure characteristic frequency , is recorded as .

[0041] Step six, judge whether is less than the set convergence residual ; If , the iteration is completed, and the structure designed according to the current , is a low dynamic load structure;

[0042] If , as the next iteration , repeat steps four to six for multiple iterations until convergence.

[0043] Changes in the string parameters, structural characteristic frequencies, and dynamic load modal numbers during the iteration process are shown in Figure 6 .

[0044] At this point, the process ends.

[0045] Example Two Structural dynamic response suppression is an important aspect to be considered in the safety design of high-speed aircraft structures. Developing effective structural dynamic response suppression methods has an important supporting role in the development of high-speed aircraft.

[0046] This example takes a local skin structure of an aircraft as an example to carry out research on structural dynamic response suppression based on modal matching, as shown in Figure 5 The low dynamic load structure design method based on multi-step iteration disclosed in this example has the following specific implementation steps: Step one, define key structural parameters: use the string mass ratio and width-thickness ratio to describe the shape and parameters of the string, define the mass ratio of the added string according to the relationship between the string mass and the original structure mass , and define the width-thickness ratio of the string according to the relationship between the string width and the thickness . By defining the structure parameters, the string shape and size are dimensionless, which facilitates the subsequent steps of bringing the structure parameters into the structure dynamic response calculation.

[0047] The schematic diagram of the aircraft skin structure and the stringed manner is shown in Figure 1 . The initial skin structure is a simply supported flat plate structure, and the length, width and thickness of the flat plate are , and carbon fiber material is used. The orientation of the string is the short edge direction of the skin structure, which is perpendicular to the flow direction of the airflow. In order to ensure the symmetry of the structure modal after stringing, the position of stringing is selected at the middle part of the skin. At the same time, the finite element simulation results can show that stringing at this position can change the characteristic frequency of the structure to the greatest extent, thereby reducing the mass of the added string.

[0048] Step two, define key flow parameters: first, define the dynamic load modal wavelength according to the disturbance migration velocity and the analysis frequency f in the turbulent boundary layer of the wall, and then define the dynamic load modal number according to the comparison relationship between the wavelength and the structural characteristic length. Taking the migration velocity condition as an example, the structural characteristic length is 0.3m.

[0049] The schematic diagram of dynamic load mode is shown in Fig. 2. Figure 2 When the disturbance migration speed is constant, the wavelength of dynamic load changes with the analysis frequency, thus showing different wave numbers in the range of structural characteristic length. Figure 2 The number of dynamic load modes is shown in Fig. 3. The distribution of dynamic load is shown in Fig. 4.

[0050] Step three, calculating the structural dynamic response: Compared with the existing dynamic response suppression research which focuses on time-frequency analysis, the present application uses the finite element method to calculate the buffeting response of the structure, and under the premise of determining the structural characteristic mode, the number of dynamic load modes is substituted into the dynamic response calculation. By changing the spatial wave number of the dynamic load, the time-space correlation characteristics of the structural dynamic response under different spatial wave numbers and analysis frequencies are obtained, and the structural dynamic response results under different spatial wave numbers are obtained.

[0051] Taking the first-order characteristic frequency of the initial skin structure as the analysis frequency, the structural vibration response under this frequency is calculated according to formula (5) by changing the number of dynamic load modes, as shown in Fig. 5. With the change of the number of dynamic load modes, the average speed and the maximum speed of the structure appear the alternating change of wave peak-valley synchronously, and the number of dynamic load modes corresponding to the first minimum point of the dynamic response is Figure 3 .

[0052] Step four, obtaining the rib size: The essence of rib design is to change the characteristic frequency of the structure so that the number of dynamic load modes reaches the expected value. In the actual design process, the expected value of the number of dynamic load modes needs to be determined first, and then the characteristic frequency of the structure under this condition is calculated inversely, and the structure is made to reach this characteristic frequency through the design of the rib size.

[0053] First, the mass ratio of the added rib is specified, taking the case of as an example. Substitute the obtained in the last step into formula (4) to inversely calculate the characteristic frequency of the ribbed structure . Then take different width-thickness ratios of the rib to calculate the characteristic frequency of the ribbed structure, when , the characteristic frequency of the structure reaches 2040Hz.

[0054] Step five, cyclic iteration of design parameters: Since after ribbing or changing the size of the rib, the law of the structural dynamic response with the spatial wave number of the dynamic load changes, the number of dynamic load modes corresponding to the first minimum point of the dynamic response is different from the expected mode number used before the size design, thus producing an error of the design parameters. In order to improve the design accuracy, multiple cyclic iterations are needed to control this error.

[0055] When the width-thickness ratio of the rib takes the value​ At the first order characteristic frequency 2040Hz, the influence of different dynamic load spatial wave numbers on dynamic response is calculated, and it is found that the dynamic response reaches a minimum value when the dynamic load spatial wave number is 0.5 , which is quite different from the expected value before design . Therefore, it is necessary to start from step four and proceed in a cycle. After two cycles, the error of the design parameters gradually converges, and the width-thickness ratio of the rib in the two cycles is and , respectively. Figure 4 The structural response of the ribbed structure obtained in each of the three cycles around the first order characteristic frequency is shown. After the first design, the dynamic response does not decrease but increases due to the large design error; after the third design, the structural dynamic response is significantly suppressed. According to the design of the rib mass ratio and the width-thickness ratio , a low dynamic load structure can be obtained.

[0056] The conventional aircraft dynamic response suppression method can adjust the dynamic load distribution on the structure surface or the structural stiffness by using flow control or structural design methods, thereby reducing the structural vibration. However, the flow control method will have a certain impact on the aerodynamic characteristics of the aircraft, which is not conducive to the overall design of the aircraft. The structural design method, such as increasing the thickness of the skin structure or increasing the damping device, can also achieve the suppression of structural vibration, but often increases the weight of the aircraft, and the control effect is also reduced under high-speed flow conditions. The low dynamic load structure design method based on multi-step iteration proposed in the present application not only does not affect the aerodynamic performance of the aircraft, but also does not cause a significant increase in the mass of the aircraft, while significantly reducing the structural response at the characteristic frequency, providing certain theoretical support for the structural safety and fine design of the aircraft.

[0057] In addition, the low dynamic load structure design method based on multi-step iteration of the embodiments of the present application can be implemented by a computer device. Figure 7 The hardware structure of the computer device of the embodiments of the present application is shown in FIG. 1. As shown in FIG. 1, the device can include a processor 201 and a memory 202 storing computer program instructions. Figure 7

[0058] Specifically, the processor 201 can include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0059] ​The memory 202 can include a mass storage for data or instructions. By way of example, and without limitation, the memory 202 can include a Hard Disk Drive (HDD), a floppy disk drive, a Solid State Drive (SSD), a flash drive, a Compact Disc Read Only Memory (CD-ROM), a Digital Versatile Disk (DVD), a Blu-Ray, a magneto-optical disk, a magnetic tape, or a Universal Serial Bus (USB) drive, or a combination of two or more of these. The memory 202 can be removable and / or non-removable (or fixed) as appropriate. The memory 202 can be internal or external as appropriate. In certain embodiments, the memory 202 is a Non-Volatile Memory. In certain embodiments, the memory 202 includes a Read-Only Memory (ROM) and a Random-Access Memory (RAM). The ROM can be a Mask-Programmed ROM, a Programmable ROM (PROM), an Erasable PROM (EPROM), an Electrically Erasable PROM (EEPROM), an Electrically Alterable ROM (EAROM), or a FLASH, or a combination of two or more of these, as appropriate. The RAM can be a Static Random-Access Memory (SRAM) or a Dynamic Random-Access Memory (DRAM), which can be a Fast Page Mode Dynamic Random-Access Memory (FPMDRAM), an Extended Data Output Dynamic Random-Access Memory (EDODRAM), a Synchronous Dynamic Random-Access Memory (SDRAM), or the like, as appropriate.

[0060] The memory 202 can be used to store or buffer various data files needed for processing and / or communication, and possible computer program instructions executed by the processor 201.

[0061] The processor 201 reads and executes the computer program instructions stored in the memory 202 to implement any of the above-mentioned embodiments of the low dynamic load structure design method based on multi-step iteration.

[0062] In some embodiments, the computer device can further include a communication interface 203 and a bus 200. As shown, the processor 201, the memory 202, and the communication interface 203 are connected through the bus 200 and complete communication with each other. Figure 7

[0063] The communication interface 203 is used to realize the communication between the modules, devices, units and / or equipment in the embodiments of the present application. The communication interface 203 can also realize data communication with other components, such as external devices, image / data acquisition devices, databases, external storage, and image / data processing workstations, etc.

[0064] ​Bus 200 includes hardware, software, or both, to couple components of the computer device to each other and to couple components to other components in the environment. Bus 200 includes, but is not limited to, at least one of the following: a data bus, an address bus, a control bus, an expansion bus, a local bus, etc. By way of example and not limitation, bus 200 can include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an InfiniBand (IB) interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or another suitable bus or combination of two or more of these. Where appropriate, bus 200 can include one or more buses. Although the present application describes and illustrates a particular bus, the present application contemplates any suitable bus or interconnect.

[0065] The computer device can execute the low dynamic load structure design method based on multi-step iteration in the embodiments of the present application, thereby realizing the low dynamic load structure design described in the present application.

[0066] In addition, in combination with the low dynamic load structure design method based on multi-step iteration in the above embodiments, the embodiments of the present application can provide a computer readable storage medium to realize. The computer readable storage medium has computer program instructions stored thereon; the computer program instructions are executed by a processor to realize any one of the low dynamic load structure design methods based on multi-step iteration in the above embodiments.

[0067] It should be noted that each technical feature of the above-mentioned embodiments can be combined with any other technical feature, and for the sake of brevity, not all possible combinations are described, but it should be understood that the scope of the present disclosure encompasses all possible combinations. In addition, each step / component described in the present application can be split into more steps / components, or two or more steps / components or parts of the operation of the steps / components can be combined into a new step / component, to achieve the purpose of the present application.

[0068] Those skilled in the art will easily understand that the above-mentioned embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for low dynamic load structure design based on multi-step iteration, characterized in that, Comprising: Step one, defining the strip parameters [α,β] representing the strip structure: according to the relationship between the strip mass and the original structure mass, the mass ratio of the added strip α is defined; according to the relationship between the strip width and the thickness, the width-thickness ratio of the added strip β is defined; Step two, 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 and the structural characteristic frequency f Step three, start the iterative design, for the original structure without rib, through the simulation to determine the structural characteristic frequency f 0 , and at the structural characteristic frequency f 0 , the dynamic response of the structure is effectively suppressed, and the dynamic load modal number is recorded as is assigned to as a non-converged non-optimal dynamic load modal number;​ Step four, in the convection velocity U c With the known situation, the Substitute the relationship in step two, obtain the structural characteristic frequency f new ; In the case of the mass ratio of the rib α is determined, by adjusting the width-thickness ratio of the rib, so that the characteristic frequency of the reinforced structure is close to f new , At this time the width-thickness ratio of the rib is recorded as β new ; [α,β new ] as the current rib structure parameters; Step five, for the structure after adding the rib [α,β new ], determine the structural characteristic frequency f s (α,β new ) by simulation, and the dynamic load modal number under which the dynamic response of the structure is effectively suppressed at the structural characteristic frequency f s (α,β new ) is recorded as Step six, judging whether it is less than or equal to a set convergence residual error ε, if not, then the next iteration Steps four to six are repeatedly executed for multiple iterations until less than the convergence residual error ε, the iteration is completed, and the structure designed according to the current [α, β new ] is a low dynamic load structure.

2. The multi-step iterative based low dynamic load structure design method of claim 1, wherein, In step one, the strip parameters [α,β] are: where w bar is the strip mass, w plate is the original structure mass without the strip, σ is the strip width, and δ is the strip thickness.

3. The multi-step iterative based low dynamic load structure design method of claim 1, wherein, In step two, the number of modes N f , structural characteristic frequency f s , and the relationship between the convection velocity U c of the structure surface and the structural characteristic frequency f In the formula, l is the characteristic length of the structure.

4. The multi-step iterative based low dynamic load structure design method of claim 3, wherein, The l is the length of the structure in the flow direction.

5. The multi-step iterative based low dynamic load structure design method of claim 1, wherein, In the step three and step five, for a structure, the structure characteristic frequency is determined by simulation, and the dynamic load modal number under which the structure dynamic response is effectively suppressed at the structure characteristic frequency is: For the current structure, the structure characteristic frequency is calculated by using the finite element method; the dynamic load modal number is changed at the calculated structure characteristic frequency, and the curve of the structure dynamic response with the change of the dynamic load modal number is obtained by simulation; The dynamic load modal number corresponding to the first minimum point of the structure dynamic response in the curve is the dynamic load modal number under which the structure dynamic response is effectively suppressed.

6. The multi-step iterative based low dynamic load structure design method of claim 5, wherein, In the curve of the structure dynamic response with the change of the dynamic load modal number, the structure dynamic response is represented by the vibration average speed.

7. An electronic device, comprising: Comprising: A processor and a memory, the memory stores programs or instructions executable on the processor, and the programs or instructions are executed by the processor to realize the steps of the low dynamic load structure design method based on multi-step iteration in any one of claims 1 to 6.

8. A readable storage medium, characterized by, A program or instruction is stored thereon, and the program or instruction is executed by the processor to realize the steps of the low dynamic load structure design method based on multi-step iteration in any one of claims 1 to 6.

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