Friction stir welding aluminum alloy I-shaped beam pressing bearing capacity design method

Abstract

The invention provides a friction stir welding aluminum alloy I-shaped beam pressure limp bearing capacity design method which comprises the following steps: acquiring key parameters of a friction stir welding aluminum alloy I-shaped beam test piece, including section size information, structural design parameters, material mechanical property indexes, welding seam parameters and geometric initial defects; calculating dimensionless parameters based on the key parameters; calculating a pressure limp bearing capacity theoretical value of the transverse stiffening rib-free aluminum alloy I-shaped beam when the transverse stiffening rib-free aluminum alloy I-shaped beam is subjected to concentrated load in the midspan according to European specifications or an American aluminum coordination design manual; real pressure limp bearing capacity data of the stirring friction welding aluminum alloy I-shaped beam are obtained through experimental testing and finite element simulation, and a correction coefficient is obtained through regression analysis fitting based on the real pressure limp bearing capacity data and dimensionless parameters; and the correction coefficient is multiplied by a standard theoretical value, or an American standard formula based on least square method regression correction is adopted, and the pressure limp bearing capacity design value of the friction stir welding aluminum alloy I-shaped beam is obtained.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of mechanical property analysis and design of aluminum alloy structures welded by friction stir welding, and particularly relates to a design method for the compression crippling capacity of an aluminum alloy I-beam welded by friction stir welding under concentrated load, which can be directly applied to the engineering design and safety evaluation of aluminum alloy I-beams welded by friction stir welding in large-span space structures. BACKGROUND

[0002] Aluminum alloy structures are widely used in large-span space structures due to their outstanding advantages of light weight, high strength, and corrosion resistance. The I-beam, as the core load-bearing component of such structures, its web under concentrated load directly determines the safety and reliability of the overall structure, and is the core control index of structural design.

[0003] To realize the forming of large-section aluminum alloy I-beams, the current mainstream technology is to combine the advantages of aluminum alloy extrusion forming and friction stir welding technology, that is, to longitudinally butt joint two T-shaped extruded parts by friction stir welding to form an I-shaped aluminum alloy beam. Compared with traditional fusion welding, friction stir welding can significantly reduce the welding strength, ductility and fatigue damage, but the heat-affected zone formed during welding will still cause material softening, which directly affects the compression crippling capacity of the I-beam and becomes a key factor affecting the mechanical properties of the component.

[0004] The current mainstream aluminum alloy structure design specifications, such as the European standard EN1999-1-1:2023 and the American Aluminum Association Design Manual AAADM-2020, provide calculation methods for the compression crippling capacity of extruded and fusion-welded aluminum alloy I-beams, but the inventors found through systematic experimental research and refined finite element simulation that these specifications have significant deviations in calculating the compression crippling capacity of aluminum alloy I-beams welded by friction stir welding: European standard deviation problem: the calculation results are too conservative, the predicted values of the single-welded and double-welded friction stir welded I-beam specimens are 45% and 17% lower than the measured bearing capacity respectively, which will cause serious material waste, poor economy, and large dispersion and low reliability of the calculation results; American standard deviation problem: when calculating the friction stir welded aluminum alloy I-beam subjected to concentrated load near the end of the component (distance less than the nominal depth d / 2), the deviation is more obvious, the predicted values of the single-welded and double-welded specimens are 133% and 85% lower than the measured bearing capacity respectively, and there are problems of large dispersion and significant data stratification.

[0005] Therefore, there is an urgent need for a calculation method that can accurately predict the compression crippling capacity of aluminum alloy I-beams welded by friction stir welding, has small dispersion and is easy to apply in engineering, in order to improve the design efficiency of such structures, ensure engineering safety, promote material saving and technological progress. SUMMARY

[0006] In view of the problems of large deviation, high discreteness and poor economy of the calculation of the compression bearing capacity of the friction stir welded aluminum alloy I-shaped beam according to the existing European specifications and American specifications, the present application provides a friction stir welded aluminum alloy I-shaped beam compression bearing capacity design method, which realizes scientific correction of the calculation results of the existing specifications by introducing a correction coefficient considering the softening effect of the heat affected zone of the friction stir welding and key geometric / technological parameters.

[0007] In order to achieve the above-mentioned purpose, the technical scheme of the present application is realized as follows: A friction stir welded aluminum alloy I-shaped beam compression bearing capacity design method, comprising the following steps: S1: obtaining key parameters of a friction stir welded aluminum alloy I-shaped beam test piece, including cross-section size information, structural design parameters, material mechanical performance indexes, weld parameters and geometric initial defects, the cross-section size information including web net height h w , web thickness t w , flange width b f , flange thickness t f , the structural design parameters including stiffener spacing a , loading plate width S s , the material mechanical performance indexes including web aluminum alloy elastic modulus E, web aluminum alloy yield strength f 0.2w , the weld parameters including weld quantity n, weld width h s , weld yield strength f sy ; based on the key parameters, dimensionless parameters are calculated: web width-height ratio , loading length to web height ratio , web height-thickness ratio , flange width-thickness ratio / , weld-base material strength-width product ratio , wherein h t is the web height except the weld width, h t = h w - h s ; S2: Based on European standard EN1999-1-1:2023 or the American Aluminum Association Design Manual AAADM-2020, calculate the theoretical value of the compressive bearing capacity of an aluminum alloy I-beam without transverse stiffeners under concentrated load at mid-span. The theoretical value includes the theoretical value from the European standard. Compared with the US normative theoretical value F U,AA ; S3: Obtain the actual compressive bearing capacity data of the friction stir welded aluminum alloy I-beam through experimental testing and finite element simulation. Based on the actual compressive bearing capacity data and the dimensionless parameters in step S1, obtain the correction coefficient through regression analysis. Multiply the correction coefficient by the theoretical value in step S2, or use the US standard formula based on least squares regression correction, to obtain the design value of the compressive bearing capacity of the friction stir welded aluminum alloy I-beam.

[0008] Furthermore, in step S2, the theoretical value of the European standard... The calculation process is as follows: ;in, For effective load-bearing length, =1.0, In the formula The buckling reduction coefficient, For the effective load length, , ,in, m 1 and m 2 is a dimensionless parameter. ,

[0009] , For buckling load, , The buckling coefficient of local compressive bearing capacity ; ,when When >0.5, 0.

[0010] Furthermore, in step S2, the US standard theoretical value F U,AA The calculation process is as follows: If the distance of the concentrated load from the end of the member is ≥ d / 2, ; If the concentrated load is less than the distance from the end of the member d / 2: when s s / d When ≤0.2 ; When s s When / d>0.2 ; Where d is the complete nominal depth of the aluminum alloy I-beam, d = hw + 2tf.

[0011] Furthermore, the correction factor in step S3 includes the European standard correction factor and the American standard correction factor; The European standard correction factor includes a single weld seam correction factor. With double weld seam correction factor ; ; ; The US standard correction factor includes a single weld seam correction factor. and the US standard double weld seam correction factor ; For a concentrated force acting at a distance equal to or greater than d / 2 from the end of the member: ; ; For a concentrated force applied from the end of a member at a distance less than d / 2: ; .

[0012] Furthermore, the US standard formula based on least squares regression correction used in step S3 is as follows: (1) Single weld a) For a concentrated force acting at a distance equal to or greater than d / 2 from the end of the member:

[0013] b) For concentrated forces applied from the end of the member at a distance less than d / 2: When ss / h≤0.2

[0014] When ss / h > 0.2

[0015] (2) Double weld a) For a concentrated force acting at a distance equal to or greater than d / 2 from the end of the member:

[0016] b) For concentrated forces applied from the end of the member at a distance less than d / 2: When ss / h≤0.2

[0017] When s s When / h>0.2 .

[0018] Furthermore, the key parameters in step S1 are obtained in the following ways: cross-sectional dimension information and structural design parameters are obtained by consulting design drawings and three-dimensional scanning; material mechanical property indicators are obtained by material mechanical property tests and literature review; geometric initial defects are obtained by three-dimensional scanning; and residual stress distribution models are obtained by consulting literature review.

[0019] Furthermore, the process of obtaining the actual bearing capacity data in step S3 includes: simulating a concentrated load scenario through a local compression test and measuring the actual compressive bearing capacity of the component; establishing a refined finite element model based on the key parameters and residual stress distribution model of step S1, simulating the compressive failure process of the component, and outputting the simulated bearing capacity data; the actual bearing capacity data is a comprehensive data of the test bearing capacity and the simulated bearing capacity.

[0020] Furthermore, the material of the friction stir welded aluminum alloy I-beam is 6061-T6 aluminum alloy, with an elastic modulus E=6942000MPa.

[0021] Furthermore, the design value for the compressive bearing capacity includes the revised design value according to European standards. Design values ​​after revision of US standards ; = × European standard correction factor = F U,AA ×US standard correction factor; or The results were calculated using the US standard formula based on least squares regression correction.

[0022] Furthermore, the method is applied to the engineering design and safety assessment of friction stir welded aluminum alloy I-beams in large-span spatial structures.

[0023] Beneficial effects: This invention introduces a ratio of width to height of the web. The ratio of loading length to web height Web height-to-thickness ratio Width-to-thickness ratio / Number of welds n Weld-base metal strength width-to-product ratio The relevant correction factors fully consider the combined effects of the softening effect of the FSW heat-affected zone, the number of welds, their width, strength, and geometric parameters on the compressive bearing capacity. Experimental verification shows that, compared to European standard EN1999-1-1:2023 and American standard AAADM-2020, the calculated results of this invention show a significantly improved agreement with experimental and refined finite element analysis results, with calculation accuracy improved by 12.8% to 31.4% and 14.4% to 31.5%, respectively, demonstrating a significant improvement in calculation accuracy.

[0024] This invention effectively controls the fluctuation range of calculation results through scientific correction coefficient design. The coefficient of variation of the calculation results is reduced by 2.4% to 45.5% compared with the current European standard and by 75.0% to 90.5% compared with the current US standard. It has better stability and reliability, and can provide more consistent and reliable load-bearing capacity data for engineering design. The dispersion of the results is significantly reduced.

[0025] This invention solves the problem of overly conservative calculation results in current standards. While ensuring structural safety, it can make fuller use of the strength properties of aluminum alloy materials, reduce material waste, lower engineering construction costs, and significantly improve the economic efficiency of FSW aluminum alloy I-beams, with outstanding economic advantages.

[0026] This invention is based on the framework of the current European standard EN1999-1-1:2023 and the American standard AAADM-2020, with a modified version. The calculation steps are clear, the parameter acquisition method is simple, and it is easy for structural engineers to understand and master. At the same time, the method can be directly integrated into existing structural design software to achieve automated calculation, greatly improve design efficiency, and facilitate its widespread application in the engineering field. It has strong practicality and scalability. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart illustrating the main process of the design method for the compressive bearing capacity of friction stir welded aluminum alloy I-beams according to an embodiment of the present invention. Figure 2 This is a simplified schematic diagram of a single-weld aluminum alloy I-beam specimen obtained from the friction stir welding method for designing the compressive bearing capacity of aluminum alloy I-beams according to an embodiment of the present invention. Figure 3 The ratio of the experimental, finite element bearing capacity (FU,T-FE) to the calculation result (FU,EN) of European standard EN1999-1-1:2023 varies with the flange regularized width-to-thickness ratio. A diagram showing the relationship between changes; Figure 4 The ratio of the experimental, finite element bearing capacity (FU,T-FE) to the calculated result (FU,EN) of the modified European standard EN1999-1-1:2023 varies with the flange regularized width-to-thickness ratio. A diagram showing the relationship between changes; Figure 5 For testing, finite element load capacity (FU, T-FE) and American standard AA ADM The ratio of (FU,AA) in the 2020 calculation results varies with the flange regularized width-to-thickness ratio. A diagram showing the relationship between changes; Figure 6 For testing, finite element load capacity (FU, T-FE) and the revised American Standard AA ADM The ratio of (FU,AA) in the 2020 calculation results varies with the flange regularized width-to-thickness ratio. A diagram showing the relationship between changes; Figure 7 For testing, finite element bearing capacity (FU,T-FE) and direct coefficient correction method, the revised American Standard AA ADM The ratio of (FU,AA) in the 2020 calculation results varies with the flange regularized width-to-thickness ratio. The relationship diagram of the changes. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0029] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] Example 1 See Figures 1-7 A method for designing the compressive bearing capacity of friction stir welded aluminum alloy I-beams, comprising the following steps: S1: Obtain key parameters for friction stir welded aluminum alloy I-beam specimens, including cross-sectional dimensions, structural design parameters, material mechanical properties, weld parameters, and initial geometric defects. The cross-sectional dimensions include the net height of the web. h w Web thickness t w wing width b f flange thickness t f The structural design parameters include the stiffening rib spacing. a Loading plate width S s The mechanical properties of the material include the elastic modulus E of the web aluminum alloy and the yield strength of the web aluminum alloy.f 0.2w The weld parameters include the number of welds n and the weld width. h s weld yield strength f sy Based on the aforementioned key parameters, the dimensionless parameter is calculated: web width-to-height ratio. The ratio of loading length to web height Web height-to-thickness ratio Slope width-to-thickness ratio / Weld-base metal strength width-to-product ratio ,in h t The web height excluding weld width. h t = h w - h s ; It should be noted that the key parameters in step S1 are obtained in the following ways: cross-sectional dimension information and structural design parameters are obtained by consulting design drawings and 3D scanning; material mechanical property indicators are obtained by material mechanical property tests and literature review; geometric initial defects are obtained by 3D scanning; residual stress distribution model is obtained by consulting literature. The material of the friction stir welded aluminum alloy I-beam is 6061-T6 aluminum alloy, and its elastic modulus E=6942000MPa.

[0031] This embodiment obtains the actual bearing capacity data of this type of component under actual stress by conducting systematic local compression tests. Based on the obtained cross-sectional dimension information, structural design parameters, material mechanical properties, weld width and yield strength, number of welds, initial geometric defects, and residual stress calculated based on the residual stress distribution model, a refined finite element model is established to obtain the actual compressive bearing capacity data of this type of component under actual concentrated force. Combining the above results, the key dimensionless parameters that have a significant impact on local pressure stability bearing capacity are analyzed, including: web width-to-height ratio. The ratio of loading length to web height Web height-to-thickness ratio Slope width-to-thickness ratio / Weld-base metal strength width-to-product ratio .

[0032] S2: Based on European standard EN1999-1-1:2023 or the American Aluminum Association Design Manual AAADM-2020, calculate the theoretical value of the compressive bearing capacity of an aluminum alloy I-beam without transverse stiffeners under concentrated load at mid-span. The theoretical value includes the theoretical value from the European standard. Compared with the US normative theoretical value F U,AA ; European standard theoretical value in step S2 The calculation process is as follows: ;in, For effective load-bearing length, =1.0, In the formula The buckling reduction coefficient, For the effective load length, , ,in, m 1 and m 2 is a dimensionless parameter. ,

[0033] , For buckling load, , The buckling coefficient of local compressive bearing capacity ; ,when When >0.5, 0.

[0034] The US standard theoretical value in step S2 F U,AA The calculation process is as follows: If the distance of the concentrated load from the end of the member is ≥ d / 2, ; If the concentrated load is less than the distance from the end of the member d / 2: when s s / d When ≤0.2 ; when s s / d >0.2 ; in, d It is the complete nominal depth of the aluminum alloy I-beam. d = h w +2 t f .

[0035] S3: Obtain the actual compressive bearing capacity data of the friction stir welded aluminum alloy I-beam through experimental testing and finite element simulation. Based on the actual compressive bearing capacity data and the dimensionless parameters in step S1, obtain the correction coefficient through regression analysis. Multiply the correction coefficient by the theoretical value in step S2, or use the US standard formula based on least squares regression correction, to obtain the design value of the compressive bearing capacity of the friction stir welded aluminum alloy I-beam. It should be noted that the process of obtaining the actual bearing capacity data in step S3 includes: simulating the concentrated load scenario through a local compression test and measuring the actual compressive bearing capacity of the component; establishing a refined finite element model based on the key parameters and residual stress distribution model in step S1, simulating the compressive failure process of the component, and outputting the simulated bearing capacity data; the actual bearing capacity data is a comprehensive data of the test bearing capacity and the simulated bearing capacity. The design value for compressive bearing capacity includes the revised design value according to European standards. Design values ​​after revision of US standards ; = × European standard correction factor = F U,AA ×US standard correction factor; or The results were calculated using the US standard formula based on least squares regression correction.

[0036] The correction factor in step S3 includes the European standard correction factor and the American standard correction factor; The European standard correction factor includes a single weld seam correction factor. With double weld seam correction factor ; ; ; The US standard correction factor includes a single weld seam correction factor. and the US standard double weld seam correction factor ; For the action at a distance equal to or greater than the end of the component d / 2 concentration: ; ; For a concentrated force applied from the end of a member at a distance less than d / 2: ; .

[0037] The US standard formula based on least squares regression correction used in step S3 is as follows: (1) Single weld a) For a concentrated force acting at a distance equal to or greater than d / 2 from the end of the member:

[0038] b) For concentrated forces applied from the end of the member at a distance less than d / 2: When s s / h≤0.2

[0039] When s s When / h>0.2

[0040] (2) Double weld a) For a concentrated force acting at a distance equal to or greater than d / 2 from the end of the member:

[0041] b) For concentrated forces applied from the end of the member at a distance less than d / 2: When s s / h≤0.2

[0042] When s s When / h>0.2 .

[0043] The method described in this embodiment can be applied to the engineering design and safety assessment of friction stir welded aluminum alloy I-beams in large-span spatial structures.

[0044] See Figures 3-7 In practice, this involves European standard calibration (correction factor calibration). Parameter acquisition (single weld):

[0045] Calibration results:

[0046] The results show that the ratios after calibration are all close to 1, indicating that the calculated results are in much better agreement with the actual bearing capacity.

[0047] Parameter acquisition (double weld seam)

[0048] Calibration results:

[0049] The results show that the ratios after calibration are all close to 1, indicating that the calculated results are in much better agreement with the actual bearing capacity.

[0050] US standard calibration (correction factor calibration): Parameter acquisition (single weld):

[0051] Calibration results:

[0052] The results show that the ratios after calibration are all close to 1, indicating that the calculated results are in much better agreement with the actual bearing capacity.

[0053] Parameter acquisition (double weld seam):

[0054] Calibration results:

[0055] The results show that the ratios after calibration are all close to 1, indicating that the calculated results are in much better agreement with the actual bearing capacity.

[0056] US standard calibration (using US standard formula calibration based on least squares regression correction): Parameter acquisition (single weld):

[0057] Calibration results:

[0058] The results show that the ratios after calibration are all close to 1, indicating that the calculated results are in much better agreement with the actual bearing capacity.

[0059] Parameter acquisition (double weld seam):

[0060] Calibration results:

[0061] The results show that the ratios after calibration are all close to 1, indicating that the calculated results are in much better agreement with the actual bearing capacity.

[0062] In summary, this invention achieves precise design of the compressive bearing capacity of friction stir welded aluminum alloy I-beams through scientific parameter acquisition, standardized calculation, and correction coefficient calibration, and has significant engineering application value.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for designing the compressive bearing capacity of friction stir welded aluminum alloy I-beams, characterized in that, Includes the following steps: S1: Obtain key parameters for friction stir welded aluminum alloy I-beam specimens, including cross-sectional dimensions, structural design parameters, material mechanical properties, weld parameters, and initial geometric defects. The cross-sectional dimensions include the net height of the web. h w Web thickness t w wing width b f flange thickness t f The structural design parameters include the stiffening rib spacing. a Loading plate width S s The mechanical properties of the material include the elastic modulus E of the web aluminum alloy and the yield strength of the web aluminum alloy. f 0.2w The weld parameters include the number of welds n and the weld width. h s weld yield strength f sy Based on the aforementioned key parameters, the dimensionless parameter is calculated: web width-to-height ratio. The ratio of loading length to web height Web height-to-thickness ratio Slope width-to-thickness ratio / Weld-base metal strength width-to-product ratio ,in h t The web height excluding weld width. h t = h w - h s ; S2: Based on European standard EN1999-1-1:2023 or the American Aluminum Association Design Manual AAADM-2020, calculate the theoretical value of the compressive bearing capacity of an aluminum alloy I-beam without transverse stiffeners under concentrated load at mid-span. The theoretical value includes the theoretical value from the European standard. Compared with the US normative theoretical value F U,AA ; S3: Obtain the actual compressive bearing capacity data of the friction stir welded aluminum alloy I-beam through experimental testing and finite element simulation. Based on the actual compressive bearing capacity data and the dimensionless parameters in step S1, obtain the correction coefficient through regression analysis. Multiply the correction coefficient by the theoretical value in step S2, or use the US standard formula based on least squares regression correction, to obtain the design value of the compressive bearing capacity of the friction stir welded aluminum alloy I-beam.

2. The method for designing the compressive bearing capacity of friction stir welded aluminum alloy I-beams according to claim 1, characterized in that, European standard theoretical value in step S2 The calculation process is as follows: ;in, For effective load-bearing length, =1.0, In the formula The buckling reduction coefficient, For the effective load length, , ,in, m 1 and m 2 is a dimensionless parameter. , , For buckling load, , The buckling coefficient of local compressive bearing capacity ; ,when When >0.5, 0.

3. The method for designing the compressive bearing capacity of friction stir welded aluminum alloy I-beams according to claim 1, characterized in that, The US standard theoretical value in step S2 F U,AA The calculation process is as follows: If the distance of the concentrated load from the end of the member is ≥ d / 2, ; If the concentrated load is less than the distance from the end of the member d / 2: When s s When / d≤0.2 ； When s s When / d>0.2 ； Where d is the complete nominal depth of the aluminum alloy I-beam, d = hw + 2tf.

4. The method for designing the compressive bearing capacity of friction stir welded aluminum alloy I-beams according to claim 1, characterized in that, The correction factor in step S3 includes the European standard correction factor and the American standard correction factor; The European standard correction factor includes a single weld seam correction factor. With double weld seam correction factor ; ； ； The US standard correction factor includes a single weld seam correction factor. and the US standard double weld seam correction factor ; For a concentrated force acting at a distance equal to or greater than d / 2 from the end of the member: ; ; For a concentrated force applied from the end of a member at a distance less than d / 2: ; 。 5. The method for designing the compressive bearing capacity of friction stir welded aluminum alloy I-beams according to claim 1, characterized in that, The US standard formula based on least squares regression correction used in step S3 is as follows: (1) Single weld a) For a concentrated force acting at a distance equal to or greater than d / 2 from the end of the member: b) For concentrated forces applied from the end of the member at a distance less than d / 2: When ss / h≤0.2 When ss / h > 0.2 (2) Double weld a) For a concentrated force acting at a distance equal to or greater than d / 2 from the end of the member: b) For concentrated forces applied from the end of the member at a distance less than d / 2: When ss / h≤0.2 When ss / h > 0.2 。 6. The method for designing the compressive bearing capacity of friction stir welded aluminum alloy I-beams according to claim 1, characterized in that, The key parameters in step S1 are obtained in the following ways: cross-sectional dimension information and structural design parameters are obtained by consulting design drawings and 3D scanning; material mechanical property indicators are obtained by material mechanical property tests and literature review; geometric initial defects are obtained by 3D scanning; and residual stress distribution models are obtained by consulting literature review.

7. The method for designing the compressive bearing capacity of friction stir welded aluminum alloy I-beams according to claim 1, characterized in that, The process of obtaining the actual bearing capacity data in step S3 includes: simulating a concentrated load scenario through a local compression test and measuring the actual compressive bearing capacity of the component; establishing a refined finite element model based on the key parameters and residual stress distribution model of step S1, simulating the compressive failure process of the component, and outputting the simulated bearing capacity data; the actual bearing capacity data is a comprehensive data of the test bearing capacity and the simulated bearing capacity.

8. The method for designing the compressive bearing capacity of friction stir welded aluminum alloy I-beams according to claim 1, characterized in that, The aluminum alloy I-beams subjected to friction stir welding are made of 6061-T6 aluminum alloy with an elastic modulus E=6942000MPa.

9. The method for designing the compressive bearing capacity of friction stir welded aluminum alloy I-beams according to claim 1, characterized in that, The design value for compressive bearing capacity includes the revised design value according to European standards. Design values ​​after revision of US standards ; = × European standard correction factor = F U,AA ×US standard correction factor; or The results were calculated using the US standard formula based on least squares regression correction.

10. The method for designing the compressive bearing capacity of friction stir welded aluminum alloy I-beams according to any one of claims 1-9, characterized in that, The method is applied to the engineering design and safety assessment of friction stir welded aluminum alloy I-beams in large-span spatial structures.

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