Rapid vibration fatigue specimen design method and device

Abstract

The invention relates to the technical field of aerospace materials, in particular to a rapid vibration fatigue specimen design method and device, and aims at solving the problems that in the prior art, vibration fatigue specimen design is long in period and high in cost, or the frequency of parts exceeds the excitation frequency range of a vibration test bed, or multi-round optimization and repeated design are needed. The method comprises the following steps: firstly, designing a reference sample, and rapidly designing a vibration fatigue sample which is simultaneously applicable to the geometrical characteristics of parts and the excitation frequency range of a vibration test bed by utilizing a dynamic similarity principle, namely determining the specific magnification or reduction multiple of the reference sample; according to the method, the vibration fatigue test sample which is simultaneously applicable to the geometrical characteristics of the parts and the excitation frequency range of the vibration test bed can be rapidly designed only according to the designed reference test sample, existing resources are well utilized, and compared with the best prior art, the design efficiency of the test sample is improved, and the method has the advantages of being high in speed and high in applicability.

Description

Technical Field

[0001] The present disclosure relates to the technical field of aerospace materials, and in particular to a method and device for designing a rapid vibration fatigue specimen. Background Art

[0002] Aerospace materials refer to various materials used in aircraft and their power units, accessories, and instruments. They are one of the decisive factors in the development of aerospace engineering technology. Aerospace materials science is also a pioneering branch of materials science. Aerospace materials have excellent high and low temperature resistance, aging resistance, and corrosion resistance, and can adapt to the space environment. One generation of materials, one generation of equipment. Aerospace materials are the technical basis for aerospace products to achieve the expected performance, life, and reliability. The fatigue strength of materials is an important basis for the selection of parts and components and the strength and life assessment. However, the mechanical properties data of materials currently used in many projects are incomplete.

[0003] High-frequency vibration tests are often used in military and civilian mechanical engineering to test the fatigue strength of materials. High-frequency vibration tests use test equipment to generate alternating inertial forces with a cyclic load frequency of about 1000Hz to act on fatigue specimens, which can meet the fatigue performance research of metal materials in service under high-frequency, low-amplitude, and high-cycle environmental conditions. In order to obtain the fatigue limit of the material, there are three methods in engineering: the first method is to customize the material blank, and then make specimens according to the standard for vibration fatigue testing; the second method is to directly use existing parts for vibration fatigue testing; the third method is to design special vibration fatigue specimens for testing based on the structural characteristics of the parts.

[0004] In the existing technologies, all three methods have shortcomings:

[0005] 1. The method of customizing blanks and making samples has the disadvantages of long cycle and high cost.

[0006] Second, vibration fatigue specimens are made using existing parts. The frequency of some of these parts exceeds the excitation frequency range of the vibration test bench (usually below 3000 Hz). Stress concentration may also exist on the existing parts, resulting in inaccurate test results.

[0007] 3. Design special vibration fatigue specimens according to the structural characteristics of existing parts. This method requires multiple rounds of optimization in the fatigue specimen design to avoid stress concentration, and the fatigue specimen needs to be redesigned according to the different part structures, and the work is highly repetitive.

[0008] In summary, the design of vibration fatigue specimens in the prior art either has a long cycle and high cost, or the frequency of the parts exceeds the excitation frequency range of the vibration test bench and there may be stress concentration phenomena that lead to inaccurate test results, or multiple rounds of optimization and repeated design are required. Summary of the invention

[0009] In view of the above problems, the present disclosure provides a rapid vibration fatigue specimen design method and device, which is used to solve the problems in the prior art of vibration fatigue specimen design, such as long cycle and high cost, or the frequency of parts exceeding the excitation frequency range of the vibration test bench and the stress concentration phenomenon that may cause inaccurate test results, or the need for multiple rounds of optimization and repeated design. The present disclosure can quickly design vibration fatigue specimens using existing parts, reduce design cycle and design cost, improve the accuracy of test results, and reduce repeated design rounds.

[0010] A rapid vibration fatigue specimen design method, the method comprising:

[0011] Design a universal reference specimen for vibration fatigue test, whose first-order natural frequency is W;

[0012] Select the parts that need to be subjected to vibration fatigue test, preliminarily determine the sample cutting plan, and according to the principle of dynamic similarity, proportionally scale the reference sample according to the existing cutting plan of the parts to obtain the design sample, so that the first-order natural frequency of the design sample is within the excitation frequency range of the vibration test bench. The design sample is the vibration fatigue sample.

[0013] Furthermore, the reference specimens designed for vibration fatigue testing include:

[0014] The reference specimen includes: a clamping section, a thin waist section and a counterweight section;

[0015] By adjusting the structural dimensions of the counterweight section and the thin waist section, the maximum point of the first-order bending vibration stress of the specimen falls on the thin neck of the thin waist section, which is the vibration fatigue cracking position;

[0016] During the test, the sample is fixed on the vibration table by the clamping section.

[0017] Furthermore, the sample cutting plan is determined, including:

[0018] According to the engine blade disk and gear web model, the disk and web structure are utilized to the maximum extent while ensuring that the vibration frequency falls within the excitation frequency range of the vibration table. The scaling size is determined according to the reference sample, the geometric size of the fatigue sample is determined, and the cutting plan is determined.

[0019] Furthermore, the first-order natural frequency of the design sample is obtained according to the material density similarity ratio, elastic modulus similarity ratio and geometric similarity ratio between the material of the design sample and the material of the reference sample, and the first-order natural frequency of the reference sample;

[0020] An appropriate geometric similarity ratio is selected so that the first-order natural frequency of the designed sample is within the excitation frequency range of the vibration test bench. The designed sample is a vibration fatigue sample.

[0021] Furthermore, according to the principle of dynamic similarity, the reference sample is enlarged or reduced, and the geometric similarity ratio A between the target design sample and the reference sample is first set. l =λ, where λ is the ratio of the size of the design sample to the reference sample, and λ is a positive number;

[0022] The material of the design specimen is different from that of the reference specimen, so the similarity ratios of material density and elastic modulus are A ρ and A E ;

[0023] According to the principle of dynamic similarity, the natural frequency similarity ratio of the design sample and the reference sample is obtained. That is, the first-order natural frequency of the designed sample is

[0024] Furthermore, after the material of the design sample is determined, the specific multiple by which the reference sample needs to be enlarged or reduced is determined according to the geometric characteristics of the part and the excitation frequency range of the vibration test bench, that is, the specific value of λ is determined, and λ is a positive number.

[0025] Furthermore, the design specimen and the reference specimen have the same stress distribution, and the stress similarity ratio is the elastic modulus similarity ratio A. σ =A E ;

[0026] The excitation frequency of the vibration test bench is the same as the first-order natural frequency of the designed specimen.

[0027] Furthermore, the specimens are designed according to the material and geometric characteristics of the parts, and the similarity relationship is used to quickly obtain vibration fatigue specimens that are compatible with the structural geometric characteristics and the excitation frequency range of the vibration table.

[0028] A rapid vibration fatigue specimen design device, the device comprising:

[0029] The benchmark design unit is used to design a universal benchmark specimen for vibration fatigue test, whose first-order natural frequency is W;

[0030] The sample design unit is used to select parts that need to be subjected to vibration fatigue test, preliminarily determine the sample cutting plan, and according to the principle of dynamic similarity, proportionally scale the reference sample according to the existing cutting plan of the parts to obtain the designed sample, so that the first-order natural frequency of the designed sample is within the excitation frequency range of the vibration test bench. The designed sample is the vibration fatigue sample.

[0031] Furthermore, the first-order natural frequency of the design sample is obtained according to the material density similarity ratio, elastic modulus similarity ratio and geometric similarity ratio between the material of the design sample and the material of the reference sample, and the first-order natural frequency of the reference sample;

[0032] According to the similarity relationship between the material mechanical properties of the design sample and the reference sample, an appropriate geometric similarity ratio is selected so that the first-order natural frequency of the design sample is within the excitation frequency range of the vibration test bench. The design sample is a vibration fatigue sample.

[0033] Furthermore, according to the principle of dynamic similarity, the reference sample is enlarged or reduced, and the geometric similarity ratio A between the target design sample and the reference sample is first set. l =λ, where λ is the ratio of the size of the design sample to the reference sample, and λ is a positive number;

[0034] The material of the design specimen is different from that of the reference specimen, so the similarity ratios of material density and elastic modulus are Aρ and AE, respectively;

[0035] According to the principle of dynamic similarity, the natural frequency similarity ratio of the design sample and the reference sample is obtained. That is, the first-order natural frequency of the designed sample is

[0036] Furthermore, according to the geometric characteristics and materials of the parts and the excitation frequency range of the vibration test bench, the specific multiple by which the reference sample needs to be enlarged or reduced is determined, that is, the specific value of λ is determined, and λ is a positive number.

[0037] Furthermore, the design specimen and the reference specimen have the same stress distribution, and the stress similarity ratio is the elastic modulus similarity ratio A. σ =A E ;

[0038] The excitation frequency of the vibration test bench is the same as the first-order natural frequency of the designed specimen.

[0039] Furthermore, based on the geometric characteristics and materials of the components, fatigue specimens with the first-order natural frequency meeting the requirements of the vibration table are quickly designed.

[0040] The present invention first designs a reference sample, and uses the principle of dynamic similarity to quickly design a vibration fatigue sample that is suitable for both the geometric characteristics of the parts and the excitation frequency range of the vibration test bench, that is, to determine the specific multiples by which the reference sample needs to be enlarged or reduced.

[0041] The present invention can quickly design a vibration fatigue specimen that is suitable for both the geometric characteristics of the parts and the excitation frequency range of the vibration test bench based on the already designed reference specimen, making better use of existing resources. Compared with the best existing technology, it improves the design efficiency of the specimen and has the advantages of fast speed and strong applicability.

[0042] On the one hand, this method has been verified to be feasible through simulation analysis using commercial software; on the other hand, it has been applied in the vibration fatigue test of a certain type of engine accessory transmission gear. Existing scrapped gears are used to quickly design and process fatigue specimens, which improves the utilization rate of parts or scrap. The vibration fatigue limits of four gears made of different materials are obtained in the test, providing a reliable basis for troubleshooting vibration fatigue faults of this type of engine gears.

[0043] Other features and advantages of the present disclosure will be described in the following description, and partly become apparent from the description, or be understood by implementing the present disclosure. The purpose and other advantages of the present disclosure can be realized and obtained by the structures indicated in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present disclosure 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 some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 This is a flow chart of the method of the embodiment of the present disclosure;

[0046] Figure 2 It is a schematic diagram of a device according to an embodiment of the present disclosure;

[0047] Figure 3 Schematic diagram of a benchmark sample according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0049] In the field of aerospace materials, vibration is a common form of motion in engineering structures and an important cause of fatigue failure of engineering structures and materials. Therefore, vibration fatigue testing is an important test method to obtain the fatigue performance of materials and structural parts under vibration conditions.

[0050] In order to obtain the fatigue limit of the material, there are three methods in engineering: the first method is to customize the material blank, and then make specimens according to the standard for vibration fatigue testing; the second method is to directly use existing parts for vibration fatigue testing; the third method is to design special vibration fatigue specimens for testing based on the structural characteristics of the parts.

[0051] In the existing technologies, all three methods have shortcomings:

[0052] 1. The method of customizing blanks and making samples has the disadvantages of long cycle and high cost.

[0053] 2. Vibration fatigue specimens are made using existing parts, some of which have frequencies exceeding the excitation frequency range of the vibration test bench (usually below 3000 Hz). The frequency of the parts exceeds the excitation frequency range of the vibration test bench and there may be stress concentration phenomena that may lead to inaccurate test results.

[0054] 3. Design special vibration fatigue specimens according to the structural characteristics of existing parts. This method requires multiple rounds of optimization in the fatigue specimen design to avoid stress concentration, and the fatigue specimen needs to be redesigned according to the different part structures, and the work is highly repetitive.

[0055] To this end, the present disclosure proposes a rapid vibration fatigue specimen design method and device, including a rapid vibration fatigue specimen design method and a rapid vibration fatigue specimen design device.

[0056] The present invention solves the problems in the prior art of vibration fatigue specimen design, such as long cycle and high cost, component frequency exceeding the excitation frequency range of the vibration test bench and possible stress concentration phenomenon leading to inaccurate test results, or the need for multiple rounds of optimization and repeated design. The present invention can quickly design vibration fatigue specimens using existing parts, reduce design cycle and design cost, improve the accuracy of test results, and reduce repeated design rounds.

[0057] like Figure 1 As shown, the present disclosure provides a rapid vibration fatigue specimen design method, the method comprising:

[0058] Design the reference sample, determine the material and first-order natural frequency of the reference sample;

[0059] Select the parts that need to be subjected to vibration fatigue test, determine the materials and determine the preliminary sample cutting plan based on the geometric characteristics of the parts;

[0060] The design specimen is obtained by scaling the reference specimen in proportion according to the existing component cutting plan, so that the first-order natural frequency of the designed specimen is within the excitation frequency range of the vibration test bench.

[0061] In the specific implementation, a reference sample is first designed, and the principle of dynamic similarity is used to quickly design a vibration fatigue sample that is suitable for the geometric characteristics of the parts and the excitation frequency range of the vibration test bench, that is, to determine the specific multiples by which the reference sample needs to be enlarged or reduced. Compared with the existing technology, the design cycle and design cost are reduced, and the number of repeated design rounds is reduced.

[0062] like Figure 1 As shown, the present invention first designs a vibration fatigue benchmark specimen based on existing parts, then selects appropriate design specimen materials, and finally obtains the design specimen by proportionally scaling the existing parts, so that the first-order natural frequency of the design specimen is within the excitation frequency range of the vibration test bench. At this time, the design specimen is a vibration fatigue specimen.

[0063] In practice, the vibration test bench has a limited excitation frequency range and can accommodate limited geometric features of tested components, so it is necessary to design the specimen to meet the conditions of the vibration test bench. The fatigue limit data of the designed specimen is measured, and then the fatigue limit data of the reference specimen is converted according to the corresponding formula.

[0064] In this embodiment, the first-order natural frequency of the design sample is obtained according to the material of the design sample and the material of the reference sample, the material density similarity ratio, the elastic modulus similarity ratio and the geometric similarity ratio between the two, and the first-order natural frequency of the reference sample;

[0065] An appropriate geometric similarity ratio is selected so that the first-order natural frequency of the designed sample is within the excitation frequency range of the vibration test bench. The designed sample is a vibration fatigue sample.

[0066] In specific implementation, the present disclosure can quickly obtain the required design samples based on the principle of dynamic similarity.

[0067] In particular, the design specimen can be made of different materials from the reference specimen, so that the design specimen of appropriate size can be designed more quickly for parts made of different materials.

[0068] In this embodiment, according to the principle of dynamic similarity, the reference sample is enlarged or reduced, and the geometric similarity ratio Al=λ between the target design sample and the reference sample is first set, where λ is the ratio of the size of the design sample to the reference sample, and λ is a positive number;

[0069] The material of the design specimen is different from that of the reference specimen, so the similarity ratios of material density and elastic modulus are Aρ and A E ;

[0070] According to the principle of dynamic similarity, the natural frequency similarity ratio of the design sample and the reference sample is obtained. That is, the first-order natural frequency of the designed sample is

[0071] In this embodiment, after the material of the sample is determined, the specific multiple by which the reference sample needs to be enlarged or reduced is determined according to the geometric characteristics of the part and the excitation frequency range of the vibration test bench, that is, the specific value of λ is determined, and λ is a positive number.

[0072] In specific implementation, the material of the designed sample is first determined, and then the specific magnification or reduction multiple of the reference sample is determined based on the geometric characteristics of the part and the excitation frequency range of the vibration test bench.

[0073] In this embodiment, the design sample and the reference sample have the same stress distribution, and the stress similarity ratio is the elastic modulus similarity ratio A. σ =A E .

[0074] In specific implementation, since the design specimen and the reference specimen are proportionally enlarged or reduced in geometric dimensions, they have the same stress distribution, and the fatigue limit of the specimen can be accurately obtained.

[0075] In this embodiment, the excitation frequency of the vibration test bench is the same as the first-order natural frequency of the designed sample.

[0076] In specific implementation, the excitation frequency of the vibration test bench is the same as the first-order natural frequency of the designed sample, so that the designed sample and the vibration test bench can form resonance and test the fatigue limit of the material to be tested.

[0077] In this embodiment, the sample is designed according to the material and geometric characteristics of the parts, and the similarity relationship is used to quickly obtain a vibration fatigue sample that is compatible with the structural geometric characteristics and the excitation frequency range of the vibration table.

[0078] During the specific implementation, the material of the component is determined, and the specimen cutting plan is determined according to the geometric characteristics of the component. The design specimen is obtained by scaling the cutting plan proportionally. One component can be processed into multiple fatigue specimens, which greatly utilizes the existing components or scrapped parts resources, speeds up the design speed, and shortens the test cycle.

[0079] like Figure 2 As shown, the present disclosure provides a rapid vibration fatigue specimen design device, the device comprising:

[0080] The benchmark design unit is used to design a universal benchmark specimen for vibration fatigue test, and its first-order natural frequency is calculated to be W;

[0081] The sample design unit is used to select parts that need to be subjected to vibration fatigue test, preliminarily determine the sample cutting plan, and according to the principle of dynamic similarity, proportionally scale the reference sample according to the existing parts cutting plan to obtain the designed sample, so that the first-order natural frequency of the designed sample is within the excitation frequency range of the vibration test bench. The designed sample is the vibration fatigue sample.

[0082] When implementing it, Figure 2 As shown, the apparatus disclosed herein includes a reference design unit for designing a reference sample and a sample design unit for designing a design sample to be tested. Figure 3 shown.

[0083] In this embodiment, the first-order natural frequency of the design sample is obtained according to the material of the design sample and the material of the reference sample, the material density similarity ratio, the elastic modulus similarity ratio and the geometric similarity ratio between the two, and the first-order natural frequency of the reference sample;

[0084] According to the similarity relationship between the material mechanical properties of the design sample and the reference sample, an appropriate geometric similarity ratio is selected so that the first-order natural frequency of the design sample is within the excitation frequency range of the vibration test bench. The design sample is a vibration fatigue sample.

[0085] In this embodiment, according to the principle of dynamic similarity, the reference sample is enlarged or reduced, and the geometric similarity ratio A between the target design sample and the reference sample is first set. l =λ, where λ is the ratio of the size of the design sample to the reference sample, and λ is a positive number;

[0086] The material of the design specimen is different from that of the reference specimen, so the similarity ratios of material density and elastic modulus are A ρ and A E ;

[0087] According to the principle of dynamic similarity, the natural frequency similarity ratio of the design sample and the reference sample is obtained. That is, the first-order natural frequency of the designed sample is

[0088] In this embodiment, after the material of the design sample is determined, the specific multiple by which the reference sample needs to be enlarged or reduced is determined according to the geometric characteristics of the part, the material and the excitation frequency range of the vibration test bench, that is, the specific value of λ is determined, and λ is a positive number.

[0089] In this embodiment, the design sample and the reference sample have the same stress distribution, and the stress similarity ratio is the elastic modulus similarity ratio A. σ =A E ;

[0090] The excitation frequency of the vibration test bench is the same as the first-order natural frequency of the designed specimen.

[0091] In this embodiment, a fatigue specimen whose first-order natural frequency meets the requirements of the vibration table is quickly designed according to the material and geometric characteristics of the parts.

[0092] The present invention can quickly design a vibration fatigue specimen that is suitable for both the geometric characteristics of the parts and the excitation frequency range of the vibration test bench based on the already designed reference specimen, making better use of existing resources. Compared with the best existing technology, it improves the design efficiency of the specimen and has the advantages of fast speed and strong applicability.

[0093] In order to enable those skilled in the art to better understand the present disclosure, the principles of the present disclosure are described as follows:

[0094] Fatigue limit refers to the maximum stress value when an infinite number of stress cycles do not cause damage, also known as the endurance limit. The fatigue limit of a material is an inherent property of the material itself, which varies due to the cycle characteristics, the form of specimen deformation, and the environment in which the material is located. It needs to be determined by fatigue testing. The determination requires the use of several smooth small-sized specimens on a dedicated fatigue testing machine.

[0095] Fatigue limit is an extremely important physical quantity in materials science, which reflects the ability of a material to withstand cyclic stress. Fatigue limit refers to the maximum stress value when an infinite number of stress cycles do not cause damage, also known as the endurance limit.

[0096] This disclosure consists of the following steps:

[0097] 1) Design a vibration fatigue specimen, referred to as a reference specimen in this disclosure, whose first-order natural frequency is W.

[0098] 2) According to the principle of dynamic similarity, the reference sample is enlarged or reduced, and the geometric similarity ratio A between the target design sample and the reference sample is first set. l =λ,λ>0.

[0099] 3) The material of the design sample is different from that of the reference sample, so the similarity ratios of material density and elastic modulus are Aρ and A E .

[0100] 4) According to the principle of dynamic similarity, the natural frequency similarity ratio between the design sample and the reference sample is obtained. That is, the first-order natural frequency of the designed sample is The excitation frequency of the vibration test bench is also The design specimen and the reference specimen have the same stress distribution, and the stress similarity ratio is the elastic modulus similarity ratio A. σ =A E .

[0101] 5) According to the geometric characteristics of the parts and the excitation frequency range of the test bench, determine the specific multiple by which the reference sample needs to be enlarged or reduced, that is, determine the specific value of λ.

[0102] Through the above steps, based on the designed benchmark specimen, the principle of dynamic similarity can be used to quickly design a vibration fatigue test specimen that is suitable for both the geometric characteristics of the parts and the excitation frequency range of the vibration test bench.

[0103] On the one hand, this method has been verified to be feasible through simulation analysis using commercial software; on the other hand, it has been applied in the vibration fatigue test of a certain type of engine accessory transmission gear. Existing scrapped gears are used to quickly design and process fatigue specimens, which improves the utilization rate of parts or scrap. The vibration fatigue limits of four gears made of different materials are obtained in the test, providing a reliable basis for troubleshooting vibration fatigue faults of this type of engine gears.

[0104] Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A method for designing a rapid vibration fatigue specimen, characterized in that: The method comprises: The reference specimen designed for vibration fatigue test has the first order natural frequency W; Select the parts that need to be subjected to vibration fatigue test, determine the sample cutting plan, and according to the principle of dynamic similarity, proportionally scale the reference sample according to the existing cutting plan of the parts to obtain the design sample, so that the first-order natural frequency of the design sample is within the excitation frequency range of the vibration test bench. The design sample is the vibration fatigue sample.

2. A rapid vibration fatigue specimen design method according to claim 1, characterized in that: Designed for reference specimens used in vibration fatigue testing, including: The reference specimen includes: a clamping section, a thin waist section and a counterweight section; By adjusting the structural dimensions of the counterweight section and the thin waist section, the maximum point of the first-order bending vibration stress of the specimen falls on the thin neck of the thin waist section, which is the vibration fatigue cracking position; During the test, the sample is fixed on the vibration table by the clamping section.

3. A rapid vibration fatigue specimen design method according to claim 1, characterized in that: Determine the sample cutting plan, including: According to the engine blade disk and gear web model, on the basis of ensuring that the vibration frequency falls within the excitation frequency range of the vibration table, the scaling size is determined according to the reference sample, the geometric size of the fatigue sample is determined, and the cutting plan is determined.

4. A rapid vibration fatigue specimen design method according to claim 1, characterized in that: According to the material of the design sample and the material of the reference sample, the material density similarity ratio, elastic modulus similarity ratio and geometric similarity ratio between the two, and the first-order natural frequency of the reference sample, the first-order natural frequency of the design sample is obtained; An appropriate geometric similarity ratio is selected so that the first-order natural frequency of the designed sample is within the excitation frequency range of the vibration test bench. The designed sample is a vibration fatigue sample.

5. A rapid vibration fatigue specimen design method according to claim 4, characterized in that: According to the principle of dynamic similarity, the reference sample is enlarged or reduced, and the geometric similarity ratio A between the target design sample and the reference sample is first set. l =λ, where λ is the ratio of the size of the design sample to the reference sample, and λ is a positive number; The material of the design specimen is different from that of the reference specimen, so the similarity ratios of material density and elastic modulus are A ρ and A E ; According to the principle of dynamic similarity, the natural frequency similarity ratio of the design sample and the reference sample is obtained. That is, the first-order natural frequency of the designed sample is 6. A rapid vibration fatigue specimen design method according to claim 5, characterized in that: After the material of the design sample is determined, the specific multiple by which the reference sample needs to be enlarged or reduced is determined according to the geometric characteristics of the part and the excitation frequency range of the vibration test bench, that is, the specific value of λ is determined, and λ is a positive number.

7. A rapid vibration fatigue specimen design method according to claim 1, characterized in that: The design specimen and the reference specimen have the same stress distribution, and the stress similarity ratio is the elastic modulus similarity ratio A. σ =A E ; The excitation frequency of the vibration test bench is the same as the first-order natural frequency of the designed specimen.

8. A rapid vibration fatigue specimen design method according to any one of claims 1 to 7, characterized in that: The design specimens are based on the material and geometric characteristics of the parts and components, and the similarity relationship is used to quickly obtain vibration fatigue specimens that are compatible with the structural geometric characteristics and the vibration table excitation frequency range.

9. A rapid vibration fatigue specimen design device, characterized in that: The device comprises: The benchmark design unit is used to design a universal benchmark specimen for vibration fatigue test, whose first-order natural frequency is W; The sample design unit is used to select parts that need to be subjected to vibration fatigue test, preliminarily determine the sample cutting plan, and according to the principle of dynamic similarity, proportionally scale the reference sample according to the existing cutting plan of the parts to obtain the designed sample, so that the first-order natural frequency of the designed sample is within the excitation frequency range of the vibration test bench. The designed sample is the vibration fatigue sample.

10. A rapid vibration fatigue specimen design device according to claim 9, characterized in that: According to the material of the design sample and the material of the reference sample, the material density similarity ratio, elastic modulus similarity ratio and geometric similarity ratio between the two, and the first-order natural frequency of the reference sample, the first-order natural frequency of the design sample is obtained; According to the similarity relationship between the material mechanical properties of the design sample and the reference sample, an appropriate geometric similarity ratio is selected so that the first-order natural frequency of the design sample is within the excitation frequency range of the vibration test bench. The design sample is a vibration fatigue sample.

11. A rapid vibration fatigue specimen design device according to claim 10, characterized in that: According to the principle of dynamic similarity, the reference sample is enlarged or reduced, and the geometric similarity ratio A between the target design sample and the reference sample is first set. l =λ, where λ is the ratio of the size of the design sample to the reference sample, and λ is a positive number; The material of the design specimen is different from that of the reference specimen, so the similarity ratios of material density and elastic modulus are A ρ and A E ; According to the principle of dynamic similarity, the natural frequency similarity ratio of the design sample and the reference sample is obtained. That is, the first-order natural frequency of the designed sample is 12. A rapid vibration fatigue specimen design device according to claim 11, characterized in that: According to the geometric characteristics of the parts, materials and the excitation frequency range of the vibration test bench, determine the specific multiple by which the reference sample needs to be enlarged or reduced, that is, determine the specific value of λ, which is a positive number.

13. The rapid vibration fatigue specimen design device according to claim 9, characterized in that: The design specimen and the reference specimen have the same stress distribution, and the stress similarity ratio is the elastic modulus similarity ratio A. σ =A E ; The excitation frequency of the vibration test bench is the same as the first-order natural frequency of the designed specimen.

14. A rapid vibration fatigue specimen design device according to any one of claims 9 to 13, characterized in that: According to the material and geometric characteristics of the parts, the fatigue specimen with the first-order natural frequency meeting the requirements of the vibration table is quickly designed.

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