Verification method for single-layer tunnel tube test of carrier rocket

Abstract

The invention provides a carrier rocket single-layer tunnel tube test verification method, which comprises the following steps: establishing a whole rocket flight model, and determining a load state of a tunnel tube in the whole flight process; designing a single-layer tunnel pipe test scheme based on the load state of the tunnel pipe in the whole flight process; establishing a single-layer tunnel pipe finite element model containing the storage tank based on the test scheme, and calculating the static load boundary state of the tunnel pipe; establishing a single-layer tunnel pipe finite element model containing a test tool based on the test scheme, and calculating dynamic load boundary conditions of the tunnel pipe; and testing the single-layer tunnel pipe based on the static load boundary state of the tunnel pipe and the dynamic load boundary condition of the tunnel pipe. Through finite element model strength simulation calculation and experimental design, test conditions are set, the actual flight loaded state of the single-layer tunnel pipe is greatly enveloped, the influence caused by the boundary effect is reduced, and the purpose of reducing the test difficulty of the single-layer tunnel pipe is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of rockets, and in particular relates to a test verification method for a single-layer tunnel tube of a launch vehicle. Background Art

[0002] The co-bottom single-layer tunnel tube structure of a liquid oxygen-methane launch vehicle is a brand-new structural design. The single-layer tunnel tube not only undertakes the role of propellant transportation but also undertakes the role of structural load-bearing. Its structural strength needs to be fully verified before flight. The inside of the tunnel tube is liquid oxygen propellant with a temperature of about -181°C, and the outside is methane propellant with a temperature of about -163°C. The outer wall of the tube is prevented from freezing by a heat insulation coating. Axial deformation is compensated by a bellows compensator along the axial direction of the tunnel tube, and radial deformation is restricted by a tie rod connected to the tank wall in the radial direction. If the strength of the single-layer tunnel tube is not satisfied, methane and oxygen will contact and explode, directly leading to the failure of the launch mission. There is an urgent need for a clear experimental method to verify whether the strength of the single-layer tunnel tube meets the requirements under the above loads.

[0003] During flight, the single-layer tunnel tube is subjected to static loads including: uneven temperature deformation, water hammer pressure during engine start-stop, and axial deformation caused by the internal pressure at the bottom of the tank. On this basis, affected by the aerodynamic load and engine thrust during flight, the single-layer tunnel tube is simultaneously subjected to axial and radial vibration loads. The test method needs to simultaneously envelope the above loads and also consider the size limitations of several meters to more than ten meters of the entire tunnel tube, and the verification difficulty far exceeds that of conventional vibration tests. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the present invention provides a test verification method for a single-layer tunnel tube of a launch vehicle, which at least partially solves the problem of great test difficulty existing in the prior art.

[0005] An embodiment of the present disclosure provides a test verification method for a single-layer tunnel tube of a launch vehicle, including:

[0006] Establish an overall rocket flight model to determine the load state of the tunnel tube during the entire flight process;

[0007] Design a test scheme for the single-layer tunnel tube based on the load state of the tunnel tube during the entire flight process;

[0008] Based on the test scheme, establish a finite element model of the single-layer tunnel tube including the tank to calculate the static load boundary state of the tunnel tube;

[0009] Based on the test scheme, establish a finite element model of the single-layer tunnel tube including the test tooling to calculate the dynamic load boundary conditions of the tunnel tube;

[0010] Conduct tests on the single-layer tunnel tube based on the static load boundary state of the tunnel tube and the dynamic load boundary conditions of the tunnel tube.

[0011] Optionally, test the single-layer tunnel tube based on the static load boundary state and dynamic load boundary conditions of the tunnel tube, including conducting an instability test on the internal pressure of the tunnel tube.

[0012] Optionally, determining the load state of the tunnel tube during the entire flight process includes:

[0013] Determining the vibration mechanical environment, temperature environment, and hydraulic load of the tunnel tube.

[0014] Optionally, designing the test scheme for the single-layer tunnel tube includes:

[0015] Setting the dimensions of the tunnel tube, and the tunnel tube test assembly includes at least one circle of tie rod groups.

[0016] Optionally, designing the test scheme for the single-layer tunnel tube includes:

[0017] Applying mechanical environment loads in a way that includes full constraint on one side of the compensator and loading on the straight pipe side;

[0018] Achieving the low-temperature internal pressure environment of the tunnel tube by filling it with liquid nitrogen.

[0019] Optionally, establishing a finite element model of the single-layer tunnel tube including a storage tank based on the test scheme, including:

[0020] The storage tank cylinder section, front and rear bottoms, short shell, compensator, and tunnel tube adopt shell elements, the flange adopts solid elements, the tie rods and gusset plate connections adopt MPC constraints, and the welds adopt co-node constraints.

[0021] Optionally, calculating the static load boundary state of the tunnel tube includes: applying temperature loads and internal pressure loads to the storage tank, and calculating the axial deformation and radial deformation of the tunnel tube. The axial deformation and radial deformation of the tunnel tube are used as the static boundary conditions for the tunnel tube test.

[0022] Optionally, establishing a finite element model of the single-layer tunnel tube including test tooling based on the test scheme and calculating the dynamic load boundary conditions of the tunnel tube, including:

[0023] During radial vibration, ensure that the forces on the tie rods are consistent, adjust the magnitude of the mechanical environment load of the excitation, and calculate and determine the value of the environmental load to be adjusted through the finite element modal superposition method;

[0024] During axial vibration, ensure that the deformation of the compensator is consistent, and envelope it by adjusting the axial static displacement of the compensator.

[0025] Optionally, testing the single-layer tunnel tube based on the static load boundary state and dynamic load boundary conditions of the tunnel tube includes:

[0026] Install the tunnel pipe on the shaking table, and paste the vibration control sensor and the measurement sensor well;

[0027] After the installation is completed, conduct liquid nitrogen precooling. After fully precooling until the pipeline freely contracts, apply the calculation result in the designed single-layer tunnel pipe test scheme on the compensator side to determine the displacement of the tooling;

[0028] Install the tie rod, paste strain gauges on the tie rod, and tighten the support rod bolts according to the strain value of the strain gauges and the calculation result in the designed single-layer tunnel pipe test scheme, so as to adjust the force on the tie rod to the preset value;

[0029] When the liquid nitrogen is precooled to the set temperature and the pressure is stabilized to the set value, start the axial vibration test;

[0030] Apply the swept-frequency vibration load according to the load after the dynamic response analysis;

[0031] After the vibration conditions are loaded, drain the liquid nitrogen, unload the tie rod tension, unload the displacement, and conduct airtightness testing and appearance inspection after returning to normal temperature.

[0032] Optionally, after the test steps for the single-layer tunnel pipe are carried out based on the static load boundary state of the tunnel pipe and the dynamic load boundary conditions of the tunnel pipe, it further includes:

[0033] If vibration failure or the internal pressure instability load does not meet the requirements, clarify the failure cause through the comparison of the finite element simulation test.

[0034] The test verification method for the single-layer tunnel pipe of the launch vehicle provided by the present invention sets the test conditions through finite element model strength simulation calculation and experimental design, greatly envelopes the actual flight load-bearing state of the single-layer tunnel pipe, reduces the influence brought by the boundary effect, and thus achieves the purpose of reducing the test difficulty of the single-layer tunnel pipe. Description of the Drawings

[0035] By describing the exemplary embodiments of the present disclosure in more detail in combination with the drawings, the above-mentioned and other objects, features, and advantages of the present disclosure will become more obvious. Among them, in the exemplary embodiments of the present disclosure, the same reference numerals generally represent the same components.

[0036] Figure 1 It is a flowchart of the test verification method for the single-layer tunnel pipe of the launch vehicle provided by the embodiments of the present disclosure;

[0037] Figure 2 It is a schematic diagram of the axial vibration of the tunnel pipe provided by the embodiments of the present disclosure;

[0038] Figure 3 It is a schematic diagram of the radial vibration of the tunnel pipe provided by the embodiments of the present disclosure. Detailed Description of the Embodiment

[0039] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0040] It should be clear that the following uses specific specific examples to illustrate the implementation manners of the present disclosure, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. The present disclosure can also be implemented or applied through other different specific implementation manners, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without making creative efforts belong to the scope of protection of the present disclosure.

[0041] It should be noted that the following describes various aspects of the embodiments within the scope of the appended claims. It should be obvious that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on the present disclosure, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, this device and / or this method can be implemented using other structures and / or functions in addition to one or more of the aspects described herein.

[0042] It should also be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present disclosure in a schematic manner, and only show the components related to the present disclosure rather than being drawn according to the number, shape and size of the components in actual implementation. The type, quantity and proportion of each component in its actual implementation can be an arbitrary change, and the component layout type may also be more complex.

[0043] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0044] For ease of understanding, as Figure 1 shown, this embodiment discloses a method for experimental verification of a single-layer tunnel tube of a launch vehicle, including:

[0045] Establish an overall rocket flight model to determine the load state of the tunnel tube during the entire flight process;

[0046] Design a single-layer tunnel tube test plan based on the load state of the tunnel tube during the entire flight process;

[0047] Establish a finite element model of the single-layer tunnel tube including the storage tank based on the test plan, and calculate the static load boundary state of the tunnel tube;

[0048] Establish a finite element model of the single-layer tunnel tube including the test tooling based on the test plan, and calculate the dynamic load boundary conditions of the tunnel tube;

[0049] Conduct tests on the single-layer tunnel tube based on the static load boundary state of the tunnel tube and the dynamic load boundary conditions of the tunnel tube.

[0050] Optionally, conduct tests on the single-layer tunnel tube based on the static load boundary state of the tunnel tube and the dynamic load boundary conditions of the tunnel tube, including conducting an internal pressure instability test on the tunnel tube.

[0051] Optionally, the determination of the load state of the tunnel tube during the entire flight process includes:

[0052] Determine the vibration mechanical environment, temperature environment, and hydraulic load of the tunnel tube.

[0053] Establish an overall rocket flight model to determine the load state of the tunnel tube during the entire flight process. For example, the overall discipline can provide the flight trajectory and provide the vibration mechanical environment, temperature environment, and hydraulic load of the tunnel tube.

[0054] Optionally, the design of the single-layer tunnel tube test plan includes:

[0055] Set the dimensions of the tunnel tube. The tunnel tube test assembly includes at least one pull rod group. The pull rod group can include 3, 4, or 5 pull rods. The function of the pull rod group is to fix the tunnel tube on the test device. One end of the pull rod is fixed on the outer circumference of the tunnel tube, and the other end of the pull rod is fixed on the test device, thereby fixing the tunnel tube and the test device together for convenient testing. As Figure 2 shown, Figure 2 the pull rod group in

[0056] Optionally, the design of the single-layer tunnel tube test plan includes:

[0057] Apply mechanical environment loads in a way that includes full restraint on one side of the compensator and loading on the straight pipe side;

[0058] Achieve the low-temperature internal pressure environment of the tunnel tube by filling it with liquid nitrogen.

[0059] Specifically, in the design of the single-layer tunnel pipe test scheme, to meet the test requirements of the single-layer tunnel pipe, first, the tunnel pipe sets appropriate tunnel pipe dimensions according to the actual experimental environment, ensuring that it contains at least one circle of tie rods; second, a mechanical environment load is applied in a way that includes full restraint on one side of the compensator and loading on the straight pipe side; third, the tie rods are fixed by setting up gantry frames in space according to the actual dimensions; finally, a low-temperature internal pressure environment of the tunnel pipe is achieved by filling it with liquid nitrogen. The test diagrams are as shown in Figure 2 and Figure 3 shown

[0060] Optionally, the establishment of a finite element model of a single-layer tunnel pipe including a storage tank based on the test scheme includes:

[0061] The barrel section, front and rear bottoms, short shell, compensator, and tunnel pipe of the storage tank adopt shell elements, and the flange adopts solid elements. The tie rods and gusset connections adopt MPC constraints, and the welds adopt co-node constraints.

[0062] That is, the barrel section, front and rear bottoms, short shell, compensator, and tunnel pipe in the finite element model of the single-layer tunnel pipe adopt shell elements, the flange adopts solid elements, the tie rods and gusset connections adopt MPC constraints, and the welds adopt co-node constraints. The rest refers to the components other than the barrel section, front and rear bottoms, short shell, compensator, and tunnel pipe of the storage tank.

[0063] Optionally, the calculation of the static load boundary state of the tunnel pipe includes: applying temperature load and internal pressure load to the storage tank, calculating the axial deformation and radial deformation of the tunnel pipe, and using the axial deformation and radial deformation of the tunnel pipe as the static boundary conditions for the tunnel pipe test.

[0064] Specifically, to establish a finite element model of a single-layer tunnel pipe including a storage tank, it is necessary to calculate the static load boundary state of the tunnel pipe. A tunnel pipe storage tank model is established according to the object to be analyzed, including main structures such as compensators, tunnel pipes, and tie rod flanges. In the establishment of the tunnel pipe storage tank model, the barrel section, front and rear bottoms, short shell, compensator, and tunnel pipe of the storage tank adopt shell elements, and the rest such as flanges adopt solid elements to ensure that the number of structural elements is as small as possible. The tie rods and gusset connections adopt MPC constraints; on the premise of not affecting the overall stiffness of the structure, the welds between components can adopt co-node constraints. Apply temperature load and internal pressure load to the storage tank, and calculate the axial deformation and radial deformation of the tunnel pipe. These deformation data are used as the static boundary conditions for the tunnel pipe test.

[0065] Optionally, the establishment of a finite element model of a single-layer tunnel pipe including test tooling based on the test scheme and the calculation of the dynamic load boundary conditions of the tunnel pipe include:

[0066] During radial vibration, ensure that the forces on the tie rods are consistent, adjust the magnitude of the mechanical environment load of the excitation, and calculate and determine the value of the environmental load to be adjusted through the finite element modal superposition method;

[0067] Specifically, when establishing a finite element model of a single-layer tunnel pipe containing test tooling, it is necessary to calculate the dynamic load boundary conditions of the tunnel pipe. Since the applied liquid medium is liquid nitrogen instead of the actual liquid used, it causes a change in the system mass matrix, and the frequency corresponding to the peak dynamic response is inconsistent with the flight state. That is, both axial vibration and radial vibration are adjusted to a certain extent. During radial vibration, the test is carried out on the principle of ensuring the same force on the tie rod. By adjusting the magnitude of the mechanical environment load of the excitation, the value of the environmental load to be adjusted can be calculated and determined by the finite element modal superposition method.

[0068] Specifically, calculating and determining the value of the environmental load to be adjusted by the finite element modal superposition method means that by establishing finite element models of different media, the influence of different media on the response frequency and response amplitude of the tunnel pipe is analyzed. For the differences between liquid oxygen in a typical flight state and liquid nitrogen in an experimental state, the following two laws are given: (a) The modal frequency is increased by 1.22 times, and the corresponding modal vibration modes are the same. (b) The response acceleration remains basically unchanged, and the force on the boundary is increased by 1.27 times. The specific analysis results are shown in Table 1.

[0069] Table 1. Comparison of simulation results of liquid nitrogen and liquid oxygen

[0070] Liquid nitrogen model Liquid oxygen model 1st order mode / z 39.7 32.4 Acceleration response / g 65 62.5 Strut force / KN 8.4 10.7

[0071] During axial vibration, the test is carried out on the principle of ensuring the same deformation of the compensator, and it can be enveloped by adjusting the axial static displacement of the compensator.

[0072] Specifically, ensuring the same axial deformation of the compensator means that in the design of the pipeline system, by adjusting the initial displacement of the compensator, it can adapt to the thermal expansion and contraction or other displacement changes of the pipeline within a certain working range, thereby ensuring the stability and adequacy of the system.

[0073] According to the calculated static load and dynamic load, experiments are carried out. The tunnel pipe is installed horizontally to avoid the risk of high-altitude operation caused by the vertical state. Fix the two ends of the tunnel pipe according to the position after temperature deformation, and then fill it with liquid nitrogen to ensure that the deformation of the compensator of the tunnel pipe can meet the design requirements. The tie rod is installed after filling with liquid nitrogen, and the load of the tie rod is controlled by adjusting the distance of the connection position of the gantry. Strain gauges should be pasted on the tie rod in advance during installation, and the load magnitude can be measured and fed back in real time through the strain gauges. The vibration experiment includes axial vibration and radial vibration, which is achieved by adjusting the position of the test bench. Figure 2 and Figure 3 as shown.

[0074] Optionally, the test on the single-layer tunnel pipe based on the static load boundary state and dynamic load boundary conditions of the tunnel pipe includes:

[0075] Install the tunnel pipe on the shaking table, and paste the vibration control sensor and the measurement sensor.

[0076] After installation, conduct pre-cooling with liquid nitrogen. After sufficient pre-cooling until the pipeline freely contracts, apply the calculation result in the designed single-layer tunnel pipe test plan on the compensator side to determine the displacement of the tooling.

[0077] Install the tie rod, paste strain gauges on the tie rod, and tighten the support rod bolts according to the strain value of the strain gauges and the calculation result in the designed single-layer tunnel pipe test plan, so as to adjust the force on the tie rod to the preset value.

[0078] When the liquid nitrogen is pre-cooled to the set temperature and the pressure is stabilized to the set value, start the axial vibration test.

[0079] Apply the swept-frequency vibration load according to the load after the dynamic response analysis. The dynamic response analysis refers to the process of detailed analysis and evaluation of the response of the system after being subjected to dynamic loads.

[0080] After the vibration conditions are loaded, drain the liquid nitrogen, unload the tension of the tie rod, unload the displacement, and conduct airtightness testing and appearance inspection after returning to normal temperature.

[0081] In one scenario, the specific implementation plan is as follows:

[0082] a) Before the test, conduct appearance inspection and airtightness detection;

[0083] b) After the detection is completed, install the product on the shaking table according to Figure 2 and Figure 3 and paste the vibration control sensor and the measurement sensor.

[0084] c) After installation, conduct pre-cooling with liquid nitrogen. After sufficient pre-cooling until the pipeline freely contracts, apply the calculation result of the test plan on the compensator side to determine the displacement of the tooling in advance.

[0085] d) Install the tie rod, paste strain gauges on the tie rod, and tighten the support rod bolts according to the strain value of the strain gauges and the calculation result in the designed single-layer tunnel pipe test plan, so as to adjust the force on the tie rod to the preset value;

[0086] e) When the liquid nitrogen is pre-cooled to below -170 °C and the pressure is stabilized at (0.7 - 0.8) MPa, start the axial vibration test;

[0087] f) Apply the swept-frequency vibration load according to the load after the dynamic response analysis;

[0088] g) After the vibration conditions are loaded, drain the liquid nitrogen, unload the tension of the tie rod, unload the displacement, and conduct airtightness testing and appearance inspection according to the set item list after returning to normal temperature.

[0089] Optionally, after the step of testing the single-layer tunnel tube based on the static load boundary state and dynamic load boundary conditions of the tunnel tube, the following steps are further included:

[0090] If vibration failure or the internal pressure instability load does not meet the requirements, the failure cause is identified through comparison with the simulation test of the finite element method.

[0091] Specifically, the internal pressure instability test of the tunnel tube is as follows: for the tunnel tube structure that has passed the vibration assessment, the internal pressure stability of the compensator of the tunnel tube and the airtightness after the vibration test are assessed.

[0092] That is, during the test, if vibration failure, internal pressure instability or the load does not meet the requirements, the failure cause is identified through comparison with the simulation test of the finite element method. For the failure cause, the above process is repeated.

[0093] In summary, the main errors between the test conditions and the flight conditions can be eliminated.

[0094] The test verification method for the single-layer tunnel tube of the launch vehicle disclosed in this embodiment gives full play to the professional advantages of structural design, overall rocket load design, strength simulation calculation and experimental design. The experimental scale is moderate, which greatly envelopes the actual flight load-bearing state of the single-layer tunnel tube, reduces the influence brought by the boundary effect, verifies the strength satisfaction of the single-layer tunnel tube structure, and contributes to improving the launch capacity of the rocket.

[0095] The basic principles of the present disclosure have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, advantages, effects, etc. mentioned in the present disclosure are only examples and not limitations, and it cannot be considered that these advantages, advantages, effects, etc. are essential for each embodiment of the present disclosure. In addition, the above-disclosed specific details are only for the purposes of illustration and easy understanding, and are not limitations. The above details do not limit the present disclosure to necessarily adopt the above specific details to implement.

[0096] In this disclosure, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. The block diagrams of devices, apparatuses, equipment, and systems involved in this disclosure are only illustrative examples and do not intend to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any way. Words such as "including", "comprising", "having", etc. are open-ended words, meaning "including but not limited to", and can be used interchangeably with each other. The words "or" and "and" used herein refer to the word "and / or", and can be used interchangeably with each other, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to", and can be used interchangeably with each other.

[0097] In addition, as used herein, the "or" used in the listing of items starting with "at least one" indicates a disjunctive listing, so that for example, the listing of "at least one of A, B, or C" means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Furthermore, the wording "exemplary" does not mean that the described examples are preferred or better than other examples.

[0098] It should also be noted that in the systems and methods of this disclosure, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent solutions of this disclosure.

[0099] Various changes, substitutions, and alterations to the technologies described herein can be made without departing from the teachings defined by the appended claims. In addition, the scope of the claims of this disclosure is not limited to the specific aspects of the processes, machines, manufactures, compositions of events, means, methods, and acts described above. Current or later-developed processes, machines, manufactures, compositions of events, means, methods, or acts that perform substantially the same function or achieve substantially the same result as the corresponding aspects described herein can be utilized. Thus, the appended claims include such processes, machines, manufactures, compositions of events, means, methods, or acts within their scope.

[0100] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to these aspects are very obvious to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the aspects shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

[0101] The foregoing description has been presented for purposes of illustration and description. In addition, this description is not intended to limit embodiments of the present disclosure to the forms disclosed herein. Although several example aspects and embodiments have been discussed above, those skilled in the art will recognize some of their variations, modifications, alterations, additions, and subcombinations.

Claims

1. A test verification method for a single-layer tunnel tube of a launch vehicle, characterized in that: include: Establish a whole rocket flight model to determine the load state of the tunnel tube during the entire flight process; Design a single-layer tunnel tube test plan based on the load state of the tunnel tube during the entire flight process; Based on the test plan, a finite element model of a single-layer tunnel tube including a tank is established to calculate the static load boundary state of the tunnel tube; Based on the test plan, a single-layer tunnel tube finite element model including the test fixture is established to calculate the dynamic load boundary conditions of the tunnel tube; The single-layer tunnel tube is tested based on the static load boundary state and dynamic load boundary condition of the tunnel tube.

2. The launch vehicle single-layer tunnel tube test verification method according to claim 1 is characterized in that: The single-layer tunnel tube is tested based on the static load boundary state and dynamic load boundary condition of the tunnel tube, including an instability test on the internal pressure of the tunnel tube.

3. The launch vehicle single-layer tunnel tube test verification method according to claim 1 is characterized in that: Determining the load state of the tunnel tube during the entire flight process includes: Determine the tunnel tube's vibration-mechanical environment, temperature environment and hydraulic loads.

4. The launch vehicle single-layer tunnel tube test verification method according to claim 1 is characterized in that: The design of the single-layer tunnel tube test plan includes: Set the tunnel tube size. The tunnel tube test assembly contains at least one tie rod set.

5. The launch vehicle single-layer tunnel tube test verification method according to claim 1 is characterized in that: The design of the single-layer tunnel tube test plan includes: The mechanical environmental load is applied by a method that includes full constraint on one side of the compensator and loading on the straight pipe side; The low temperature internal pressure environment of the tunnel tube is achieved by filling it with liquid nitrogen.

6. The launch vehicle single-layer tunnel tube test verification method according to claim 1, characterized in that: The method of establishing a finite element model of a single-layer tunnel tube including a tank based on a test scheme includes: The tank section, front and rear bottom, short shell, compensator and tunnel pipe adopt shell elements, the flange adopts solid elements, the tie rod and angle piece connection adopts MPC constraints, and the weld adopts common node constraints.

7. The launch vehicle single-layer tunnel tube test verification method according to claim 6 is characterized in that: The calculation of the static load boundary state of the tunnel tube includes: Apply temperature load and internal pressure load to the tank; The axial deformation and radial deformation of the tunnel pipe are calculated, and the axial deformation and radial deformation of the tunnel pipe are used as static boundary conditions for the tunnel pipe test.

8. The launch vehicle single-layer tunnel tube test verification method according to claim 1 is characterized in that: The method of establishing a single-layer tunnel tube finite element model including a test fixture based on the test plan and calculating the dynamic load boundary conditions of the tunnel tube includes: During radial vibration, ensure that the force on the tie rod is consistent, adjust the size of the mechanical environmental load of the excitation, and determine the environmental load value to be adjusted by finite element modal superposition method; During axial vibration, the deformation of the compensator is ensured to be consistent, and the axial static displacement of the compensator is adjusted to envelope it.

9. The launch vehicle single-layer tunnel tube test verification method according to claim 1, characterized in that: The test on the single-layer tunnel tube based on the static load boundary state of the tunnel tube and the dynamic load boundary condition of the tunnel tube includes: Install the tunnel pipe on the vibration platform and affix the vibration control sensor and measurement sensor; After installation, liquid nitrogen precooling is carried out. After the pipeline is fully precooled to the point where it can shrink freely, the calculation results in the designed single-layer tunnel pipe test scheme are applied to the compensator side to determine the displacement of the tooling; Install the tie rod, paste the strain gauge on the tie rod, and tighten the support rod bolt according to the strain value of the strain gauge and the calculation result in the design single-layer tunnel pipe test plan, so as to adjust the force of the tie rod to the preset value; After the liquid nitrogen is precooled to the set temperature and the pressure is stabilized to the set value, the axial vibration test begins; Apply frequency sweep vibration load according to the load after dynamic response analysis; After the vibration condition loading is completed, the liquid nitrogen is emptied, the tension of the pull rod is unloaded, the displacement is unloaded, and the air tightness test and appearance inspection are carried out after returning to normal temperature.

10. The launch vehicle single-layer tunnel tube test verification method according to claim 1, characterized in that: After the step of testing the single-layer tunnel pipe based on the static load boundary state of the tunnel pipe and the dynamic load boundary condition of the tunnel pipe, the method further includes: If vibration failure occurs or the internal pressure instability load does not meet the requirements, the cause of the failure will be clarified through finite element simulation test comparison.

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