A design method for reusable bearing cylinder

Abstract

The present invention relates to a design method for a reusable bearing cylinder, which belongs to the field of spacecraft structure design; it includes the steps of: determining the structural composition of the bearing cylinder; designing the honeycomb core material, inner and outer skin materials and the ply angle, and the front and rear end frame materials; designing the structural parameters of the honeycomb core, inner and outer skins, and the front and rear end frames according to the index requirements; gluing and assembling the front and rear end frames with the honeycomb sandwich wallboard, and the inner and outer skins with the honeycomb core; performing a peeling test on the bonding surface of the front and rear end frames with the honeycomb sandwich wallboard to determine whether the peeling strength design margin requirements are met; performing a spacecraft identification level test on the bearing cylinder to determine whether there is damage; analyzing the residual stiffness of the bearing cylinder, and determining whether the bending stiffness index of the bearing cylinder section is met; performing a spacecraft identification level test on the bearing cylinder again to complete the verification of the reusability of the bearing cylinder. The present invention can take into account the mission use requirements and the low-cost and high-efficiency development requirements, and can provide a reference for the application of spacecraft structural engineering.

Description

Technical Field

[0001] The invention belongs to the field of spacecraft structure design and relates to a design method for a reusable load-bearing cylinder. Background Art

[0002] With the popularization of the demand for the development of low-cost and high-efficiency spacecraft, reducing the development cost and cycle of spacecraft has become an important assessment indicator for the structural design and implementation of spacecraft, while meeting the requirements of flight test missions.

[0003] New spacecraft structures usually need to go through ground development stages such as scheme, prototype, and final prototype, and participate in final prototype flight test missions. Spacecraft have the characteristics of multiple single-machine loads, multiple systems, and multiple mission conditions, which leads to large differences in the functions, performance, and interface requirements of spacecraft structures at various development stages; at the same time, the development of new spacecraft needs to pass environmental test assessments of full-coverage conditions represented by mechanics and thermodynamics at each stage, which will have a great impact on the performance of structural products. Therefore, in order to ensure indicator compliance and application reliability, new and complex spacecraft structural products at home and abroad still adopt the basic idea of ​​independent matching at each stage. Structural products that have undergone test assessments in the scheme and prototype development stages will no longer be used in final prototype flight test missions. The independent matching of final prototype structural products will inevitably lead to an increase in development costs and an extension of the development cycle. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art and to propose a design method for a reusable load-bearing cylinder, which can take into account both mission use requirements and low-cost, high-efficiency development needs, and can provide a reference for spacecraft structural engineering applications.

[0005] The solution of the present invention is:

[0006] A design method for a reusable bearing cylinder, comprising:

[0007] Step 1: determine the structural composition of the load-bearing cylinder, including a honeycomb sandwich wall panel, a front frame and a rear frame; the honeycomb sandwich wall panel includes a honeycomb core, an inner skin and an outer skin;

[0008] Step 2: Design the honeycomb core material, inner skin material and ply angle, outer skin material and ply angle, front frame material and rear frame material;

[0009] Step 3: Design the structural parameters of the honeycomb core, the structural parameters of the inner and outer skins, and the structural parameters of the front and rear frames according to the requirements of the axial compression mechanical load of the bearing tube, the axial tensile mechanical load, the bending stiffness of the bearing tube section, and the margin index; and meet the strength design margin requirements;

[0010] Step 4: Glue and assemble the front frame and the rear frame to the honeycomb sandwich wallboard; glue and assemble the inner skin and the outer skin to the honeycomb core;

[0011] Step 5: Under a heat load environment of -40°C to 60°C, a peeling test is performed on the bonding surfaces of the front frame and the rear frame and the honeycomb sandwich wallboard to obtain the maximum peeling load of the interface, and determine whether the requirement of the peeling strength design margin being not less than 1.15 is met; if the requirement is met, proceed to step 6; if the requirement is not met, glue is repaired between the front frame, the rear frame and the honeycomb sandwich wallboard until the requirement is met, and proceed to step 6;

[0012] Step 6: Perform a spacecraft identification test on the load-bearing cylinder. After the test, perform damage detection on the load-bearing cylinder. When the load-bearing cylinder is not damaged, proceed to step 8. When the load-bearing cylinder is damaged, proceed to step 7.

[0013] Step 7: Construct a finite element model of the bearing cylinder damage, and apply the axial compression mechanical load and axial tensile mechanical load in step 3 to the model; when the indicators are met, return to step 4, repair the damaged position with glue until there is no damage in the spacecraft identification test, and proceed to step 8; when the indicators are not met, return to step 3 and increase the height of the honeycomb core until the bending stiffness of the bearing cylinder section is not less than 2.4×10 8 N·m 2 If the indicator is met, proceed to step 4, repair the damaged position with glue until there is no damage in the spacecraft identification test, and proceed to step 8;

[0014] Step 8: Conduct spacecraft identification level tests on the load-bearing cylinder again to complete the verification of the reuse of the load-bearing cylinder.

[0015] In the above-mentioned reusable load-bearing tube design method, in step one, the honeycomb sandwich wall panel is a cylindrical structure; the front end frame and the rear end frame are respectively installed at the axial ends of the honeycomb sandwich wall panel; the honeycomb core is a cylindrical structure; the inner skin is attached to the inner wall of the honeycomb core; and the outer skin is attached to the outer wall of the honeycomb core.

[0016] In the above-mentioned reusable load-bearing cylinder design method, in the step 2, the honeycomb core adopts an aluminum honeycomb structure of 5A02 material; the inner skin and the outer skin both adopt high-strength medium-modulus T800HB carbon fiber reinforced AG80 epoxy resin prepreg; the front end frame and the rear end frame both adopt 2A14 aluminum alloy material; the thickness of the inner skin and the outer skin is 0.8mm, and the ply angles of the inner skin and the outer skin are the same, both [(+45 / -45) / 0 / 0 / 90 / 0 / 0 / (-45 / +45)].

[0017] In the above-mentioned design method of a reusable bearing cylinder, in step 3, the size of the honeycomb core is 4mm×0.04mm; the height of the honeycomb core is 16-18mm, and the thickness of the inner skin and the outer skin is 1mm; the front frame and the rear frame are both F-shaped sections, the thickness of the horizontal edge plate of the end frame is 5mm, the height of the vertical web is 50mm, and the thickness is 2-4mm; the bending stiffness of the cross section of the bearing cylinder using the above design is 3.02×10 8 N·m 2 , the design margin is 0.26.

[0018] In the above-mentioned design method of a reusable load-bearing tube, the honeycomb core, inner skin, outer skin, front frame and rear frame adopt the above-mentioned structural design to achieve a buckling stability margin of 1.29 for the honeycomb sandwich wall panel, a lateral pressure strength design margin of 2.70, a honeycomb shear strength design margin of 0.56, and a skin strength design margin of 0.27, all of which meet the requirement that the design margin is not less than 0.25; the design margin of the shear strength of the glue layer between the end frame and the honeycomb sandwich wall panel is 1.64, which meets the requirement that the design margin is not less than 1.15.

[0019] In the above-mentioned reusable bearing cylinder design method, in step 6, the spacecraft identification level test includes a high temperature load thermal balance test and a low temperature load thermal balance test;

[0020] Among them, the high-temperature load thermal balance test has a test temperature of +60°C and a duration of 60 days; the low-temperature load thermal balance test has a test temperature of -20°C and a duration of 20 days.

[0021] In the above-mentioned reusable load-bearing tube design method, the damage of the load-bearing tube in the spacecraft identification level vibration test is one or more of the following situations: debonding between the front frame and the honeycomb sandwich wall panel, debonding between the rear frame and the honeycomb sandwich wall panel, delamination of the inner skin or delamination of the outer skin; the glue repair treatment is to repair the glue at the corresponding debonding position or skin delamination position.

[0022] In the above-mentioned reusable bearing cylinder design method, in step 7, the construction method of the bearing cylinder damage finite element model is:

[0023] The honeycomb core, front frame and rear frame all adopt hexahedral units; the inner skin and outer skin adopt shell units; adhesives are used to connect in the bonding area, and no connection is set at the debonding or delamination position.

[0024] In the above-mentioned design method of a reusable bearing cylinder, in the steps 5 and 7, the method of filling the glue is:

[0025] Open glue injection holes with a diameter of 1mm at the upper and lower ends of the debonding area respectively, and inject glue from the lower injection hole until glue overflows from the upper injection hole. Wait until the glue solidifies.

[0026] In the above-mentioned reusable load-bearing cylinder design method, the adhesive liquid adopts J-133 low-viscosity room-temperature curing structural adhesive.

[0027] The beneficial effects of the present invention compared with the prior art are:

[0028] (1) The present invention is designed to pass environmental test assessments of all working conditions represented by mechanics and thermodynamics in various stages when developing the load-bearing cylinder, so that the performance of the load-bearing cylinder product structure produced is stable under any working conditions;

[0029] (2) The present invention sets the axial compression mechanical load of the bearing cylinder to be 214 kN, the axial tensile mechanical load to be 200 kN, and the bending stiffness of the cross section of the bearing cylinder to be no less than 2.4×10 8 N·m 2 , the margin is not less than 0.25, and according to the indicators, the honeycomb core material, inner skin material and layer angle, outer skin material and layer angle, front frame material and rear frame material, honeycomb core structural parameters, design the structural parameters of the inner skin and outer skin, design the structural parameters of the front frame and rear frame, and the design idea of ​​the load-bearing tube is comprehensive;

[0030] (3) The present invention adopts a design method combining structure and finite element modeling, which not only improves the bearing cylinder intuitively from the perspective of structural damage, but also combines finite element analysis to analyze the residual stiffness of the bearing cylinder, further ensuring the reliability of the designed bearing cylinder;

[0031] (4) In step eight, the present invention again conducts a spacecraft identification-level test on the load-bearing cylinder to complete the verification of the reuse of the load-bearing cylinder, that is, the prototype flight test mission has been completed, and there is no need to carry out independent prototype structure product matching, and it can be directly applied to the mission, thereby reducing the R&D cost and cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a flow chart for the design of the bearing cylinder;

[0033] Figure 2 It is a schematic diagram of the load-bearing cylinder structure of the present invention. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the embodiments.

[0035] The present invention provides a design method for a reusable load-bearing cylinder. The design and implementation method can minimize product matching requirements, reduce development costs, shorten development cycles, and provide a useful reference for promoting low-cost and high-efficiency engineering applications of spacecraft.

[0036] Reusable bearing cylinder design methods, such as Figure 1 As shown, the specific steps include:

[0037] Step 1: Determine the structural composition of the load-bearing cylinder, including honeycomb sandwich wall panels, front frame and rear frame, such as Figure 2 As shown. The honeycomb sandwich panel includes a honeycomb core, an inner skin and an outer skin. The honeycomb sandwich panel is a cylindrical structure; the front frame and the rear frame are respectively installed at the axial ends of the honeycomb sandwich panel; the honeycomb core is a cylindrical structure; the inner skin is attached to the inner wall of the honeycomb core; and the outer skin is attached to the outer wall of the honeycomb core.

[0038] Step 2: Design the honeycomb core material, inner skin material and layup angle, outer skin material and layup angle, front frame material and rear frame material; the honeycomb core adopts an aluminum honeycomb structure made of 5A02 material; both the inner skin and the outer skin adopt high-strength medium-modulus T800HB carbon fiber reinforced AG80 epoxy resin prepreg; both the front frame and the rear frame adopt 2A14 aluminum alloy material; the thickness of the inner skin and the outer skin is 0.8mm, and the layup angles of the inner skin and the outer skin are the same, both [(+45 / -45) / 0 / 0 / 90 / 0 / 0 / (-45 / +45)].

[0039] Step 3: The axial compression mechanical load of the bearing cylinder is 214kN, the axial tensile mechanical load is 200kN, and the bending stiffness of the bearing cylinder section is not less than 2.4×10 8 N·m 2 , margin is not less than 0.25, design the structural parameters of the honeycomb core, the structural parameters of the inner skin and the outer skin, and the structural parameters of the front frame and the rear frame; and meet the strength design margin requirements; the size of the honeycomb core is 4mm×0.04mm; the height of the honeycomb core is 16-18mm, the thickness of the inner skin and the outer skin is 1mm; the front frame and the rear frame are both F-shaped sections, the thickness of the horizontal edge plate of the end frame is 5mm, the height of the vertical web is 50mm, and the thickness is 2-4mm; the bending stiffness of the section of the load-bearing tube using the above design is 3.02×10 8 N·m 2 , the design margin is 0.26.

[0040] The honeycomb core, inner skin, outer skin, front frame and rear frame adopt the above structural design to achieve a buckling stability margin of 1.29 for the honeycomb sandwich wall panel, a design margin of 2.70 for the lateral pressure strength, a design margin of 0.56 for the honeycomb shear strength, and a design margin of 0.27 for the skin strength, all of which meet the requirement that the design margin is not less than 0.25; the design margin of the shear strength of the glue layer between the end frame and the honeycomb sandwich wall panel is 1.64, meeting the requirement that the design margin is not less than 1.15.

[0041] Step 4: Glue and assemble the front frame and the rear frame to the honeycomb sandwich wallboard; glue and assemble the inner skin and the outer skin to the honeycomb core.

[0042] Step 5. Under a heat load environment of -40℃ to 60℃, perform a peel test on the bonding surfaces of the front end frame and the rear end frame and the honeycomb sandwich wall panels to obtain the maximum peel load of the interface and determine whether the requirement of a peel strength design margin of not less than 1.15 is met; if the requirement is met, proceed to step 6; if the requirement is not met, perform glue repair between the front end frame, the rear end frame and the honeycomb sandwich wall panels until the requirement is met, and proceed to step 6.

[0043] Step six: Conduct spacecraft qualification level tests on the load-bearing cylinder. The spacecraft qualification level tests include high-temperature load thermal balance tests and low-temperature load thermal balance tests. The high-temperature load thermal balance test has a test temperature of +60°C and a duration of 60 days. The low-temperature load thermal balance test has a test temperature of -20°C and a duration of 20 days.

[0044] After the test, the load-bearing tube is inspected for damage; when the load-bearing tube is not damaged, proceed to step eight; when the load-bearing tube is damaged, proceed to step seven; the damage to the load-bearing tube in the spacecraft identification-level vibration test is one or more of the following situations: debonding between the front frame and the honeycomb sandwich wall panel, debonding between the rear frame and the honeycomb sandwich wall panel, stratification of the inner skin or stratification of the outer skin; the glue repair process is to repair the glue at the corresponding debonding position or skin stratification position.

[0045] Step 7: Construct a finite element model of the bearing tube damage. The construction method of the bearing tube damage finite element model is as follows: the honeycomb core, front frame and rear frame are all made of hexahedral units; the inner skin and outer skin are made of shell units; adhesives are used to connect in the bonding area, and no connection is set at the debonding or delamination position. Apply an axial compression mechanical load of 214kN and an axial tensile mechanical load of 200kN to the model; analyze the residual stiffness of the bearing tube and determine whether the bending stiffness of the bearing tube section is not less than 2.4×10 8 N·m 2 When the indicator is met, return to step 4, repair the damaged position with glue until there is no damage in the spacecraft identification test, and enter step 8; when the indicator is not met, return to step 3 and increase the height of the honeycomb core until the bending stiffness of the load-bearing tube section is not less than 2.4×10 8 N·m 2 If the indicator is met, go to step 4, repair the damaged position with glue until there is no damage in the spacecraft identification test, and go to step 8.

[0046] The method of glue filling is:

[0047] Open 1mm diameter injection holes at the upper and lower ends of the debonding area, and inject glue from the lower injection hole until glue overflows from the upper injection hole, and wait for the glue to solidify. The glue is J-133 low-viscosity room-temperature curing structural glue.

[0048] Step 8: Conduct spacecraft identification level tests on the load-bearing cylinder again to complete the verification of the reuse of the load-bearing cylinder.

[0049] Example

[0050] The bearing cylinder in the embodiment has a diameter of 1750 mm, a height of 1480 mm, and a cross-sectional bending stiffness index of not less than 2.4×10 8 N·m 2 , thermal load -40℃~60℃, axial compression mechanical load is 214kN, and axial tensile mechanical load is 200kN.

[0051] The design method of the bearing cylinder is more detailed and includes the following steps:

[0052] 1) The load-bearing cylinder adopts a honeycomb sandwich structure, including a honeycomb sandwich wall panel, a front frame, and a rear frame. The front frame, the rear frame and the honeycomb sandwich wall panel are assembled by gluing;

[0053] 2) The honeycomb sandwich panel skin material adopts high-strength medium-modulus T800HB carbon fiber reinforced AG80 epoxy resin prepreg, and the honeycomb core adopts 5A02 aluminum honeycomb;

[0054] 3) Both the front and rear frames are machined from 2A14 aluminum alloy forgings;

[0055] 4) The cross-sectional bending stiffness index is not less than 2.4×10 8 N·m 2 The design skin thickness is 0.8mm and the ply angle is [(+45 / -45) / 0 / 0 / 90 / 0 / 0 / (-45 / +45)].

[0056] 5) According to the requirements of axial compression mechanical load of 214kN and axial tensile mechanical load of 200kN. The honeycomb core is designed to be a medium-low density 4×0.04mm 5A02 aluminum honeycomb, with a honeycomb core height of 18mm (the total thickness of the honeycomb sandwich wall is 20mm); the end frame (front and rear end frame) adopts an F-shaped section, the horizontal edge plate thickness of the end frame is 5mm, and the thickness is increased to 12mm at the local connection point, the vertical web height is 50mm, and the thickness is 2~4mm. Under this design state, the bending stiffness of the load-bearing tube section is 3.02×10 8 N·m 2, the design margin is 0.26, which meets the requirement of design margin not less than 0.25. Under this design state, the buckling stability margin of the honeycomb sandwich panel is 1.29, the design margin of lateral pressure strength is 2.70, the design margin of honeycomb shear strength is 0.56, and the design margin of skin strength is 0.27, all of which meet the requirement of design margin not less than 0.25; under this design state, the design margin of shear strength of the glue layer of the end frame and honeycomb sandwich panel is 1.64, which meets the requirement of design margin not less than 1.15;

[0057] 6) According to the index requirements of thermal load -40℃~60℃, the peel strength analysis of the bonding surface was carried out. The analysis showed that the maximum peel load in the bonding surface area was 2760N / m, and the peel strength design margin was 1.17, which met the design margin requirement of not less than 1.15;

[0058] 7) At the initial prototype stage, the bearing cylinder participated in the vibration test of the whole spacecraft identification level. During the test, the pre-vibration and re-vibration curves of the whole spacecraft were well matched, and there was no obvious residual strain or frequency drift phenomenon, which showed that the bearing cylinder product was in normal condition and maintained good performance. After the vibration test verification, the accuracy measurement results of the bearing cylinder were consistent, and non-destructive testing showed no new defects;

[0059] 8) In the prototype stage, the load-bearing cylinder participated in the thermal test of the entire spacecraft, and underwent high-temperature load thermal balance assessment (+60°C, duration 10 days) and low-temperature load thermal balance assessment (-20°C, duration 2 days). During the high-temperature test, strain jumps occurred in some skin areas of the bonding surface area between the end frame and the honeycomb sandwich wall panel, indicating that damage may have occurred in the bonding area. After the thermal test verification, the accuracy measurement results of the load-bearing cylinder were consistent, and non-destructive testing showed that there were 8 debonding defects in the bonding area between the rear end frame and the honeycomb sandwich wall panel, accounting for 0.8% of the total bonding area;

[0060] 9) Finite element modeling is performed on the bonding area between the rear end frame of the load-bearing tube and the honeycomb sandwich wall panel. The honeycomb core and end frame use hexahedron units, the skin uses shell units, the bonding area is connected by adhesives, and the units in the bonding damage area are not connected. For details, see Figure 2 . According to the index requirements of axial compression mechanical load of 214kN and axial tensile mechanical load of 200kN, the shear strength of the adhesive layer of the rear end frame and honeycomb sandwich wall was calculated, and the design margin was 1.43;

[0061] 10) According to the non-destructive testing results, the adhesive debonding areas of the rear end frame and honeycomb sandwich wallboard are repaired with glue. Specifically, J-133 low-viscosity room temperature curing structural adhesive is selected, and glue injection holes with a diameter of Φ1 are opened at the upper and lower ends of a single debonding area, and glue is injected from the lower glue injection hole until glue overflows from the upper glue injection hole. After the structural adhesive is cured, a secondary non-destructive test is performed on the debonding area, and the test results show that there are no defects exceeding the standard;

[0062] 11) For the thermal test that caused the damage to the load-bearing tube, a separate thermal test of the load-bearing tube was carried out. The thermal test conditions refer to step 8). The strain measurement during the test and the non-destructive testing results after the test were normal, with no new defects, indicating that the damage in the first thermal test was caused by the weak interface in the bonding area between the end frame and the honeycomb sandwich wall panel. After the first thermal test assessment, the performance of the load-bearing tube tended to be stable;

[0063] 12) According to the task requirements of the prototype stage, the stiffness, strength and precision indicators of the load-bearing tube are kept consistent with the requirements of the initial prototype stage. The stiffness design margin of the load-bearing tube to be reused is 0.26, which meets the design margin requirement of not less than 0.15; the buckling stability design margin of the honeycomb sandwich wall panel is 1.29, the lateral pressure strength design margin is 2.70, the honeycomb shear strength design margin is 0.56, and the skin strength design margin is 0.27, all of which meet the design margin requirement of not less than 0.15; the shear strength design margin of the glue layer of the end frame and honeycomb sandwich wall panel is 1.43, and the peel strength design margin is 1.17, which meets the design margin requirement of not less than 1.0. After evaluation, the load-bearing tube can meet the requirements of reuse in the prototype stage;

[0064] 13) During the prototype stage, the bearing cylinder participated in the whole device thermal test and acceptance level vibration test. The test process data was normal. After the test verification, the accuracy measurement results of the bearing cylinder were consistent, and the non-destructive testing showed no new defects. The bearing cylinder product has undergone flight test mission assessment and has good performance.

[0065] The present invention adopts a reusable bearing cylinder design and implementation method, which reduces the number of bearing cylinder products required for the entire development cycle of the spacecraft by 50%, reduces the development cost by more than 30%, and shortens the development cycle by 3 months. Therefore, this reusable bearing cylinder design and implementation method can significantly reduce the low cost of spacecraft development and improve development efficiency, and has good engineering application prospects.

[0066] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A design method for a reusable bearing cylinder, characterized in that: include: Step 1: Determine the structural composition of the load-bearing cylinder, including honeycomb sandwich wall panels, front frame and rear frame; The honeycomb sandwich panel includes a honeycomb core, an inner skin and an outer skin; Step 2: Design the honeycomb core material, inner skin material and ply angle, outer skin material and ply angle, front frame material and rear frame material; Step 3: Design the structural parameters of the honeycomb core, the structural parameters of the inner and outer skins, and the structural parameters of the front and rear frames according to the requirements of the axial compression mechanical load of the bearing tube, the axial tensile mechanical load, the bending stiffness of the bearing tube section, and the margin index; and meet the strength design margin requirements; Step 4: Glue and assemble the front frame and the rear frame to the honeycomb sandwich wallboard; glue and assemble the inner skin and the outer skin to the honeycomb core; Step 5: Under a heat load environment of -40°C to 60°C, a peeling test is performed on the bonding surfaces of the front frame and the rear frame and the honeycomb sandwich wallboard to obtain the maximum peeling load of the interface, and determine whether the requirement of the peeling strength design margin being not less than 1.15 is met; if the requirement is met, proceed to step 6; if the requirement is not met, glue is repaired between the front frame, the rear frame and the honeycomb sandwich wallboard until the requirement is met, and proceed to step 6; Step 6: Perform a spacecraft identification test on the load-bearing cylinder. After the test, perform damage detection on the load-bearing cylinder. When the load-bearing cylinder is not damaged, proceed to step 8. When the load-bearing cylinder is damaged, proceed to step 7. Step 7: Construct a finite element model of the bearing cylinder damage, apply the axial compression mechanical load and axial tensile mechanical load in step 3 to the model; analyze the residual stiffness of the bearing cylinder, and determine whether the bending stiffness of the bearing cylinder section is not less than 2.4×10 8 N·m 2 When the indicator is met, return to step 4, repair the damaged position with glue until there is no damage in the spacecraft identification test, and enter step 8; when the indicator is not met, return to step 3 and increase the height of the honeycomb core until the bending stiffness of the load-bearing tube section is not less than 2.4×10 8 N·m 2 If the indicator is met, proceed to step 4, repair the damaged position with glue until there is no damage in the spacecraft identification test, and proceed to step 8; Step 8: Conduct spacecraft identification level tests on the load-bearing cylinder again to complete the verification of the reuse of the load-bearing cylinder.

2. A reusable bearing cylinder design method according to claim 1, characterized in that: In step 1, the honeycomb sandwich wall panel is a tubular structure; the front end frame and the rear end frame are respectively installed at the axial ends of the honeycomb sandwich wall panel; the honeycomb core is a tubular structure; the inner skin is attached to the inner wall of the honeycomb core; and the outer skin is attached to the outer wall of the honeycomb core.

3. A reusable bearing cylinder design method according to claim 1, characterized in that: In the step 2, the honeycomb core adopts an aluminum honeycomb structure of 5A02 material; the inner skin and the outer skin both adopt high-strength medium-modulus T800HB carbon fiber reinforced AG80 epoxy resin prepreg; the front end frame and the rear end frame both adopt 2A14 aluminum alloy material; the thickness of the inner skin and the outer skin is 0.8 mm, and the ply angles of the inner skin and the outer skin are the same, both [(+45 / -45) / 0 / 0 / 90 / 0 / 0 / (-45 / +45)].

4. A reusable bearing cylinder design method according to claim 1, characterized in that: In step 3, when the axial compressive mechanical load of the bearing cylinder is 214 kN, the axial tensile mechanical load is 200 kN, and the bending stiffness of the bearing cylinder section is not less than 2.4×10 8 N·m 2 , when the margin index requirement is not less than 0.25, the honeycomb core size is 4mm×0.04mm; the honeycomb core height is 16-18mm, and the thickness of the inner skin and the outer skin are both 1mm; the front frame and the rear frame are both F-shaped sections, the thickness of the horizontal edge plate of the end frame is 5mm, the height of the vertical web is 50mm, and the thickness is 2-4mm; the bending stiffness of the section of the load-bearing tube using the above design is 3.02×10 8 N·m 2 , the design margin is 0.

26.

5. A reusable bearing cylinder design method according to claim 4, characterized in that: The honeycomb core, inner skin, outer skin, front frame and rear frame adopt the above-mentioned structural design, so that the buckling stability margin of the honeycomb sandwich wall panel is 1.29, the lateral pressure strength design margin is 2.70, the honeycomb shear strength design margin is 0.56, and the skin strength design margin is 0.27, all of which meet the requirement that the design margin is not less than 0.25; the design margin of the shear strength of the glue layer between the end frame and the honeycomb sandwich wall panel is 1.64, which meets the requirement that the design margin is not less than 1.

15.

6. A reusable bearing cylinder design method according to claim 1, characterized in that: In step 6, the spacecraft qualification test includes a high temperature load thermal balance test and a low temperature load thermal balance test; Among them, the high-temperature load thermal balance test has a test temperature of +60°C and a duration of 60 days; the low-temperature load thermal balance test has a test temperature of -20°C and a duration of 20 days.

7. A reusable bearing cylinder design method according to claim 6, characterized in that: The damage to the load-bearing tube during the spacecraft identification-level vibration test is one or more of the following situations: debonding between the front frame and the honeycomb sandwich wall panel, debonding between the rear frame and the honeycomb sandwich wall panel, delamination of the inner skin or delamination of the outer skin; the glue repair treatment is to repair the glue at the corresponding debonding position or skin delamination position.

8. A reusable bearing cylinder design method according to claim 7, characterized in that: In the step 7, the construction method of the bearing cylinder damage finite element model is: The honeycomb core, front frame and rear frame all adopt hexahedral units; the inner skin and outer skin adopt shell units; adhesives are used to connect in the bonding area, and no connection is set at the debonding or delamination position.

9. The design method of a reusable bearing cylinder according to claim 1, characterized in that: In step 5 and step 7, the method of glue filling is: Open glue injection holes with a diameter of 1mm at the upper and lower ends of the debonding area respectively, and inject glue from the lower injection hole until glue overflows from the upper injection hole. Wait until the glue solidifies.

10. A reusable bearing cylinder design method according to claim 9, characterized in that: The adhesive liquid adopts J-133 low-viscosity room-temperature curing structural adhesive.

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