Method for checking buckling of round pipes without reinforcing ribs in batches based on DNV-RP-C202 specifications

Abstract

The invention discloses a method for checking buckling of round pipes without reinforcing ribs in batches based on DNV-RP-C202 specifications, which comprises the following steps of: writing a post-processing program, extracting the maximum axial force, the maximum bending moment, the maximum torque and the maximum shearing force borne by each pressed round pipe, and respectively substituting the maximum axial force, the maximum bending moment, the maximum torque and the maximum shearing force into calculation formulas of corresponding stress components, so as to obtain the buckling of the round pipes without reinforcing ribs. Wherein the angle theta of the dangerous point position is determined by traversing 12 angles with # imgabs0 # as an interval within 0-2pi to obtain the maximum value of von Mises equivalent stress sigma j, sd of each pipe, and the maximum value is compared with the calculated buckling strength fksd corresponding to the circular pipe, so that whether each circular pipe meets the buckling requirement of the DNV-RP-C202 specification on the circular pipe without the reinforcing rib or not is judged. Whether buckling of a large number of pressed round pipes of the type in the structure meets the requirement or not needs to be checked, the method can be adopted for rapid checking, and therefore the effects of improving the calculation efficiency and saving the time cost are achieved.

Description

Technical Field

[0001] The present invention relates to offshore steel structure engineering design technology, and more specifically, to a method for batch checking buckling of unreinforced circular tubes based on DNV-RP-C202 specification. Background Art

[0002] Thin-walled structures subjected to compressive loads will buckle when the compressive load reaches the critical load, which greatly reduces the bearing capacity of the structure, leading to engineering accidents and causing economic losses. Therefore, during design, buckling checks must be performed to meet the requirements of the specifications. However, the critical load obtained by the eigenvalue buckling analysis method of finite element software is usually greater than the critical load of the actual structure, so this method is usually not used in engineering analysis.

[0003] Therefore, most designers either use manual calculations, that is, extract the stress calculated by finite element software and directly substitute it into the corresponding formula of DNV specifications for calculation, or use Excel tables to further process and calculate the extracted stress, and the latter is mostly focused on the buckling check of flat plates. These two methods are cumbersome, inefficient and prone to errors. At present, there is no method for batch checking the buckling of unreinforced circular tubes based on DNV-RP-C202 specifications. Therefore, providing a method that can quickly and accurately check the buckling strength of unreinforced circular tubes has high engineering practical significance. Summary of the invention

[0004] In view of the defects existing in the prior art, the purpose of the present invention is to provide a method for batch checking the buckling of circular tubes without stiffeners based on the DNV-RP-C202 specification, which can realize fast and accurate checking of the buckling strength of circular tubes without stiffeners.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A method for batch checking buckling of unreinforced circular tubes based on DNV-RP-C202 specification comprises the following steps:

[0007] S1, select the research object, analyze the structural stress, and determine the working condition combination;

[0008] S2, establish the structural finite element model;

[0009] S3, check whether the calculated maximum stress component and maximum von Mises equivalent stress meet the requirements of DNV-OS-C201 specification. If yes, proceed to step S4; if not, improve the design;

[0010] S4, write a post-processing program to traverse all the compressed circular tubes and extract the maximum axial force N of each circular tube. sd , maximum bending moment M1,sd and M 2,sd , maximum torque T sd , maximum shear force Q 1,sd and Q 2,sd ;

[0011] S5, according to the maximum internal force extracted above, calculate the corresponding stress components respectively, and synthesize the stress components to obtain the von Mises equivalent stress σ of each circular tube j,sd The maximum value of the stress component σ is output. a,sd , σ m,s d ， σ h,sd , τ sd ;

[0012] S6, respectively judge σ a,sd , σ m,sd , σ h,sd Is it greater than or equal to 0. If it is greater than or equal to 0, then σ a0,sd , σ m0,sd , σ h0,sd Take 0 respectively. If it is less than 0, then σ a0,sd , σ m0,sd , σ h0,sd Take σ a,sd , σ m,sd , σ h,sd The absolute value of

[0013] S7, according to the elastic modulus, Poisson's ratio, radius, thickness, length of each circular tube, calculate the elastic buckling strength f of the circular tube under axial force, bending moment, torque or shear force, and lateral pressure. Ea 、f Em 、f Eτ 、f Eh ;

[0014] S8, the von Mises equivalent stress σ of each tube j,sd The maximum value, yield strength f y , elastic buckling strength f Ea , f Em , f Eτ , f Eh , stress component σ a0,sd , σ m0,sd , σ h0,sd , τ sd Substitute the reduced slenderness ratio The expression of is, Obtain

[0015] S9, according to the following formula In the range, determine the material coefficient γ M The value of .

[0016] S10, will reduce the slenderness ratio Substitute the characteristic buckling strength f ks The expression is: Where f y is the yield strength of the material;

[0017] S11, the characteristic buckling strength f ks and material coefficient γ M Substitute the buckling strength f ksd The expression is: The buckling strength f is calculated ksd The value of

[0018] S12, determine the von Mises equivalent stress σ of each circular tube j,sd Is the maximum value of less than the corresponding buckling strength f ksd If yes, then the buckling requirements for unreinforced circular tubes in DNV-RP-C202 are met. If not, the design needs to be improved and the yield strength and buckling strength of the structure need to be rechecked.

[0019] Preferably, the step S3 specifically includes:

[0020] According to different working conditions, loads and boundary conditions are applied to the structural finite element model to obtain a deformation cloud diagram of the structure;

[0021] If the deformation is consistent with the actual situation, then determine whether the calculated maximum stress component and maximum von Mises equivalent stress meet the yield strength requirements of DNV-OS-C201, that is, they should not exceed the allowable stress;

[0022] If not, the design needs to be improved and recalculated until the yield strength requirements of DNV-OS-C201 are met.

[0023] Preferably, the step S5 specifically includes:

[0024] According to the maximum axial force N in step S4 sd , Maximum bending moment M 1,sd and M 2,sd , Maximum torque T sd , maximum shear force Q 1,sd and Q 2,sd Substitute the following corresponding stress component calculation formulas respectively:

[0025]

[0026] τ sd =|τ T，sd +τ Q,sd |

[0027] In the formula, r is the radius of the tube, and t is the wall thickness of the tube;

[0028] The angle θ to determine the location of the dangerous point is traversed within 0-2π. The stress components are synthesized into von Mises equivalent stress σ according to the following formula at 12 angles spaced apart. j,sd ,Right now because P sd is the air pressure (constant) or the sin, cos function of θ (hydraulic pressure). Since there is no hydraulic pressure, the air pressure is relatively small, so it is approximately taken as 0 here, and the von Mises equivalent stress σ of each circular tube is obtained. j,sd The maximum value of the stress component σ is output. a,sd , σ m,sd , σ h,sd , τ sd .

[0029] Preferably, the step S7 specifically includes:

[0030] According to the elastic modulus, Poisson's ratio, radius, thickness and length of each circular tube, the elastic buckling strength f corresponding to the axial force, bending moment, torque or shear force and lateral pressure of the circular tube is calculated respectively. Ea 、f Em 、f Eτ 、f Eh , the elastic buckling strength is calculated as follows:

[0031]

[0032] In the formula, E is the elastic modulus, v is the Poisson's ratio, t is the wall thickness of the tube, and l is the length of the tube;

[0033] When i=a, ψ=1,

[0034] When i=m, ψ=1,

[0035] When i=τ, ψ=5.34, ρ=0.6,

[0036] Where r is the radius of the tube;

[0037] When i=h, ψ=4, ρ=0.6,

[0038] The present invention provides a method for batch checking the buckling of unreinforced circular tubes based on the DNV-RP-C202 specification, which can quickly and accurately check the buckling strength of unreinforced circular tubes. Compared with the existing buckling checking method for compressed thin-walled structures, the batch checking method for buckling of unreinforced circular tubes of the present invention has the advantages of being simple, efficient, not prone to error, and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a flow chart of a method for batch checking buckling of circular tubes without stiffeners based on DNV-RP-C202 specification of the present invention;

[0040] Figure 2 It is a von Mises equivalent stress cloud diagram of a converter station chassis under static load conditions obtained by calculation of the finite element software ANSYS in the embodiment of the method for batch checking buckling of circular tubes without stiffeners according to the DNV-RP-C202 specification of the present invention;

[0041] Figure 3 It is a von Mises equivalent stress cloud diagram of No. 72 brace pipe in an embodiment of the method for batch checking buckling of circular tubes without stiffeners based on DNV-RP-C202 specification of the present invention. DETAILED DESCRIPTION

[0042] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0043] Combination Figure 1 As shown, the present invention provides a method for batch checking buckling of circular tubes without stiffeners based on DNV-RP-C202 specification, comprising the following steps:

[0044] S1, select the research object, analyze the structural stress, and determine the working condition combination;

[0045] S2, establish the structural finite element model, including the establishment of the geometric model, assigning corresponding material properties to the components, dividing the mesh, and checking the mesh quality;

[0046] S3, applying loads and boundary conditions to the structural finite element model according to different working conditions, and solving to obtain a deformation cloud diagram of the structure;

[0047] If the deformation is consistent with the actual situation, determine whether the calculated maximum stress component and maximum von Mises equivalent stress meet the yield strength requirements of the DNV-OS-C201 specification, that is, they should not exceed the allowable stress; if not, it is necessary to improve the design and recalculate until the yield strength requirements of the DNV-OS-C201 specification are met;

[0048] S4, write a post-processing program to traverse all the compressed circular tubes and extract the maximum axial force N of each circular tube. sd , Maximum bending moment M 1,sd and M 2,sd , Maximum torque T sd , maximum shear force Q 1,sd and Q 2,sd ;

[0049] S5, the maximum axial force N sd , Maximum bending moment M 1,sd and M 2,sd , Maximum torque T sd , maximum shear force Q 1,sd and Q 2,sd Substitute the following corresponding stress component calculation formulas respectively:

[0050]

[0051] τ sd =|τ T,sd +τ Q,sd |

[0052] In the formula, r is the radius of the tube, and t is the wall thickness of the tube;

[0053] The angle θ to determine the location of the dangerous point is traversed within 0-2π. The stress components are synthesized into von Mises equivalent stress σ according to the following formula at 12 angles spaced apart. j,sd ,Right now because P sd is the air pressure (constant) or the sin or cos function (hydraulic pressure). Since there is no hydraulic pressure, the air pressure is relatively small and is approximately taken as 0. The von Mises equivalent stress σ of each circular tube is obtained. j,sd The maximum value of the stress component σ is output. a,sd , σ m,sd , σ h,sd , τ sd ;

[0054] S6, respectively judge σ a,sd , σ m,sd , σ h,sd Is it greater than or equal to 0? If so, then σ a0,sd , σ m0,sd , σ h0,sd Take 0 respectively. If not, then σ a0,sd , σ m0,sd , σ h0,sd Take σ a,sd , σ m,sd , σ h,sd The absolute value of

[0055] S7, according to the elastic modulus, Poisson's ratio, radius, thickness, length of each circular tube, calculate the elastic buckling strength f of the circular tube under axial force, bending moment, torque or shear force, and lateral pressure. Ea 、f Em 、f Eτ 、f Eh , the elastic buckling strength is calculated as follows:

[0056]

[0057] In the formula, E is the elastic modulus, ν is the Poisson's ratio, t is the wall thickness of the tube, and l is the length of the tube;

[0058] When i=a, ψ=1,

[0059] When i=m, ψ=1,

[0060] When i=τ, ψ=5.34, ρ=0.6,

[0061] Where r is the radius of the tube;

[0062] When i=h, ψ=4, ρ=0.6,

[0063] S8, the von Mises equivalent stress σ of each circular tube j,sd The maximum value, yield strength f y , elastic buckling strength f Ea 、f Em 、f Eτ 、f Eh , stress component σ a0,sd , σ m0,sd , σ h0,sd , τ sd , substitute the reduced slenderness ratio The expression of is:

[0064] Obtain

[0065] S9, reduce the slenderness ratio according to the following formula In the range, the material coefficient γ M The value of is:

[0066]

[0067] S10, will reduce the slenderness ratio Substitute the characteristic buckling strength f ksThe expression is:

[0068]

[0069] In the formula, f y is the yield strength of the material;

[0070] S11, the characteristic buckling strength f ks and material coefficient γ M Substitute the buckling strength f ksd The expression is:

[0071] The buckling strength f is calculated ksd The value of

[0072] S12, determine the von Mises equivalent stress σ of each circular tube j,sd Is the maximum value of less than the corresponding buckling strength f ksd If yes, then the buckling requirements of DNV-RP-C202 for circular tubes without stiffeners are met; if not, the design needs to be improved and the yield strength and buckling strength of the structure need to be rechecked.

[0073] Example

[0074] This embodiment takes the static load condition of a converter station chassis as an example to specifically illustrate the batch verification method for buckling of unreinforced circular tubes based on the DNV-RP-C202 specification provided in this embodiment, including the following steps:

[0075] S1, the converter station chassis is selected as the research object. For static load conditions, the main forces include the deadweight of the converter station and the deadweight of the chassis;

[0076] S2, the finite element model of the converter station chassis is established using the finite element software ANSYS. The origin of the coordinate is located at the center of the secondary longitudinal beam, the direction along the longitudinal beam is the X-axis direction, and the vertical direction is the Z-axis direction. The longitudinal beam, cross beam, secondary longitudinal beam, longitudinal beam connecting rod, and support pipe are modeled using beam188 units, the connection between the abutment and the support pipe is simulated using MPC184 rigid beam units, and the wooden beam under the longitudinal beam is simulated using spring units Combine39;

[0077] S3, limit the vertical displacement of the wooden beams under the four rows of longitudinal beams of the chassis, limit the displacement of the second row of longitudinal beams in the X direction, and limit the displacement of the center point of the second row of longitudinal beams in the Y direction. The deadweight of the converter station is converted to 12 pedestals, that is, the corresponding vertical load is applied at the center of the pedestal respectively, and the gravity acceleration is applied as the deadweight of the chassis. After calculation, the maximum von Mises stress of the chassis is 106.37MPa<0.6f y , meeting the yield strength requirements in DNV-OS-C201. Figure 2 is the corresponding von Mises equivalent stress cloud diagram;

[0078] S4, where the brace tube is under pressure and may buckle, and a buckling check is required. Since these brace tubes are all circular tubes without reinforcement ribs, the batch buckling check method for circular tubes without reinforcement ribs of this embodiment is suitable. This embodiment uses the APDL language to write a post-processing program to achieve the above purpose. First, define the section number, the inner and outer radii of the circular tube, and the array of the number of rods of each section, and traverse all circular tube sections to obtain the inner and outer radii, quantity and total number of circular tubes corresponding to different sections. Define the line number array of all circular tube sections, the length of the circular tube, the wall thickness of the circular tube, the maximum axial force of the circular tube, the maximum bending moment, the maximum torque, the maximum shear force and all arrays needed for subsequent calculations. Create and read in a macro file, traverse all compressed circular tubes by line number, and obtain the maximum axial force N in all units on each circular tube through a loop. sd , maximum bending moment M 1,sd and M 2,sd , maximum torque T sd , maximum shear force Q 1,sd and Q 2,sd ;

[0079] S5, the maximum axial force N sd , maximum bending moment M 1,sd and M 2,sd , maximum torque T sd , maximum shear force Q 1,sd and Q 2,sd Substitute the following calculation formulas for the corresponding stress components: τ sd =|τ T,sd +τ Q,sd |, where r is the radius of the tube, t is the wall thickness of the tube, and the angle θ to determine the position of the dangerous point is traversed within 0-2π. The stress components are synthesized into von Mises equivalent stress σ according to the following formula at 12 angles spaced apart. j,sd ,Right now because P sd is the air pressure (constant) or sinθ, cosσ function (hydraulic pressure). Since there is no hydraulic pressure, the air pressure is relatively small, so it is approximately taken as 0 here, and the von Mises equivalent stress σ of each tube is obtained. j,sd The maximum value of the stress component σ is output. a,sd , σ m,sd , σ h,sd , τ sd ;

[0080] S6, respectively judge σ a,sd , σ m,sd , σ h,sd Is it greater than or equal to 0? If so, then σa0,sd , σ m0,sd , σ h0,sd Take 0 respectively. If not, then σ a0,sd , σ m0,sd , σ h0,sd Take σ a,sd , σ m,sd , σ h,sd The absolute value of

[0081] S7, calculate the corresponding f according to the elastic modulus, Poisson's ratio, radius, thickness and length of each circular tube. Ea 、f Em 、f Eτ 、f Eh , the elastic buckling strength is calculated as follows:

[0082]

[0083] In the formula, E is the elastic modulus, v is the Poisson's ratio, t is the wall thickness of the tube, and l is the length of the tube;

[0084] When i=a, ψ=1,

[0085] When i=m, ψ=1,

[0086] When i=τ, ψ=5.34, ρ=0.6,

[0087] Where r is the radius of the tube;

[0088] When i=h, ψ=4, ρ=0.6,

[0089] S8, the von Mises equivalent stress σ of each circular tube j,sd The maximum value, yield strength f y , elastic buckling strength f Ea 、f Em 、f Eτ 、f Eh , stress component σ a0,sd , σ m0,sd , σ h0,sd , τ sd , substitute the reduced slenderness ratio The expression of is:

[0090] Obtain

[0091] S9, reduce the slenderness ratio according to the following formula In the range, the material coefficient γM The value of is:

[0092]

[0093] S10, will reduce the slenderness ratio Substitute the characteristic buckling strength f ks The expression is:

[0094]

[0095] In the formula, f y is the yield strength of the material;

[0096] S11, the characteristic buckling strength f ks and material coefficient γ M Substitute the buckling strength f ksd The expression is:

[0097] The buckling strength f is calculated ksd The value of

[0098] S12, determine the von Mises equivalent stress f of each circular tube j,sd Is the maximum value of less than the corresponding buckling strength f ksd If yes, then the buckling requirements of DNV-RP-C202 for circular tubes without stiffeners are met; if no, the design needs to be improved and the yield strength and buckling strength of the structure need to be rechecked. The following table shows the buckling check results of each brace tube under static load conditions. It can be seen from the results that for static load conditions, the brace tubes in the chassis meet the buckling requirements.

[0099]

[0100] In order to confirm the correctness of the post-processing program, this example takes No. 72 round tube as an example to manually calculate σ j,sd and f ksd , and compare it with the program calculation results. First find the maximum axial force N in all units of rod 72 sd , maximum bending moment M 1,sd and M 2,sd , maximum torque T sd , maximum shear force Q 1,sd and Q 2,sd , the angle θ traverses the range from 0 to 2π For the 12 angles spaced apart, we get σ j,sd The maximum value of the corresponding angle θ is

[0101]

[0102] τ sd =|τT,sd +T Q，sd |=1.162775MPa

[0103] σ h,sd =0

[0104]

[0105] Then calculate f ksd , we need to first obtain Values:

[0106]

[0107] σ a0,sd =-σ a,sd =10.971889MPa

[0108]

[0109] σ m0,sd =-σ m,sd =7.17MPa

[0110]

[0111] σ h0,sd =-σ h,sd =0

[0112] τ sd =1.162775MPa

[0113]

[0114] in, ψ=1,

[0115]

[0116]

[0117]

[0118] in, ψ=1,

[0119]

[0120] Due to σ h0sd = 0, so f is no longer given Eh The calculation process.

[0121]

[0122] in, ψ=5.34,ρ=0.6

[0123] ξ=0856Z l 3 / 4 =614.085

[0124]

[0125]

[0126] σ j,sd ≤f ksd

[0127] Will σ j,sd , f ksd Compared with the λ,σ in the first row of the table _jsdm , f _ksd By comparison, it can be seen that the post-processing result is written correctly. Figure 3 The von Mises equivalent stress cloud diagram of the No. 72 round tube shows that the maximum von Mises stress of the No. 72 round tube is 19.3523MPa, which is about 5.7% different from the von Mises stress of 18.2520MPa obtained by the above post-processing method. There are two possible reasons for this difference. One is that "the angle θ traverses the range of 0-2π to is 12 angles spaced apart, where is relatively large, that is, the location of the maximum von Mises stress may be contained in The technical personnel who apply the present invention can reduce the interval to improve the calculation accuracy. The difference between the two is about 4.7%. Second, the finite element model in the above example uses beam elements, while the formula in the DNV-RP-C202 specification is based on plate and shell theory.

[0128] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A method for batch checking the buckling of unreinforced circular tubes based on DNV-RP-C202 specification, characterized in that: By writing a post-processing program, the maximum axial force, maximum bending moment, maximum torque, and maximum shear force of each compressed circular tube are extracted, and the maximum axial force, maximum bending moment, maximum torque, and maximum shear force are respectively substituted into the calculation formula of the corresponding stress components. The angle θ to determine the position of the dangerous point is traversed within 0-2π. The vonMises equivalent stress σ of each circular tube is obtained by using 12 angles at intervals. j,sd The maximum value of the value is compared with the calculated buckling strength f of the circular tube. ksd By comparison, it can be determined whether each circular tube meets the buckling requirements of DNV-RP-C202 for circular tubes without stiffeners.

2. The method for batch checking buckling of unreinforced circular tubes based on DNV-RP-C202 specification according to claim 1 is characterized in that: The method specifically comprises the following steps: S1, select the research object, analyze the structural stress, and determine the working condition combination; S2, establish the structural finite element model; S3, checking whether the maximum stress component and the maximum von Mises equivalent stress meet the requirements, if yes, proceeding to step S4, if not, improving the design; S4, extract the maximum axial force, maximum bending moment, maximum torque and maximum shear force of each circular tube respectively; S5, obtain the maximum value of the von Mises equivalent stress of each circular tube and output the corresponding stress component; S6, judging whether the stress component is greater than or equal to 0, if so, taking 0 respectively, if not, taking the absolute value respectively; S7, calculate the corresponding elastic buckling strength respectively; S8, find the reduced slenderness ratio; S9, determine the value of the material coefficient according to the range of the reduced slenderness ratio; S10, calculate the characteristic buckling strength according to the value of the reduced slenderness ratio; S11, calculation of buckling strength; S12, determine whether the maximum value of the von Mises equivalent stress of each circular tube is less than the corresponding buckling strength. If so, end; if not, improve the design.

3. The method for batch checking buckling of unreinforced circular tubes based on DNV-RP-C202 specification according to claim 2 is characterized in that: The step S3 specifically includes: According to different working conditions, loads and boundary conditions are applied to the structural finite element model to obtain a deformation cloud diagram of the structure; If the deformation is consistent with the actual situation, then determine whether the calculated maximum stress component and maximum von Mises equivalent stress meet the yield strength requirements of DNV-OS-C201, that is, they should not exceed the allowable stress; If not, the design needs to be improved and recalculated until the yield strength requirements of DNV-OS-C201 are met.

4. The method for batch checking buckling of unreinforced circular tubes based on DNV-RP-C202 specification according to claim 2 is characterized in that: The step S5 specifically includes: According to the maximum axial force N in step S4 sd , Maximum bending moment M 1,sd and M 2,sd , Maximum torque T sd , maximum shear force Q 1,sd and Q 2,sd Substitute the following corresponding stress component calculation formulas respectively: t sd =|τ T,sd +t Q,sd | In the formula, r is the radius of the tube, and t is the wall thickness of the tube; The angle θ to determine the location of the dangerous point is traversed within 0-2π. The stress components are synthesized into von Mises equivalent stress σ according to the following formula at 12 angles spaced apart. j,sd ,Right now Get the vonMises equivalent stress σ of each circular tube j,sd The maximum value of the stress component σ is output. a,sd , σ m,sd , σ h,sd , τ sd .

5. The method for batch checking buckling of unreinforced circular tubes based on DNV-RP-C202 specification according to claim 4 is characterized in that: The step S6 specifically includes: Determine σ a,sd , σ m,sd , σ h,sd Is it greater than or equal to 0? If so, then σ a0,sd , σ m0,sd , σ h0,sd Take 0 respectively. If not, then σ a0,sd , σ m0,sd , σ h0,sd Take σ a,sd , σ m,sd , σ h,sd The absolute value of .

6. The method for batch checking buckling of unreinforced circular tubes based on DNV-RP-C202 specification according to claim 5 is characterized in that: The step S7 specifically includes: According to the elastic modulus, Poisson's ratio, radius, thickness, and length of each circular tube, calculate the corresponding f Ea 、f Em 、f Eτ 、f Eh , the elastic buckling strength is calculated as follows: In the formula, E is the elastic modulus, v is the Poisson's ratio, t is the wall thickness of the tube, and l is the length of the tube; When i=m, ψ=1, When i=τ, ψ=5.34, ρ=0.6, Where r is the radius of the tube; When i=h, ψ=4, ρ=0.6, 7. The method for batch checking buckling of unreinforced circular tubes based on DNV-RP-C202 specification according to claim 6 is characterized in that: The step S8 specifically includes: The von Mises equivalent stress σ of each circular tube j,sd The maximum value, yield strength f t , elastic buckling strength f Ed 、f Em 、f Eτ 、f Eh , stress component σ a0,sd , σ m0,sd , σ h0,sd , τ sd , substitute the reduced slenderness ratio The expression of is: Obtain 8. The method for batch checking buckling of unreinforced circular tubes based on DNV-RP-C202 specification according to claim 7 is characterized in that: In step S9, the slenderness ratio is reduced according to the following formula: In the range, the material coefficient γ M The value of is:

9. The method for batch checking buckling of unreinforced circular tubes based on DNV-RP-C202 specification according to claim 8 is characterized in that: In step S10, the slenderness ratio is reduced Substitute the characteristic buckling strength f ks The expression is: In the formula, f y is the yield strength of the material.

10. The method for batch checking buckling of unreinforced circular tubes based on DNV-RP-C202 specification according to claim 9 is characterized in that: In step S11, the characteristic buckling strength f ks and material coefficient γ M Substitute the buckling strength f ksd The expression is: The buckling strength f is calculated ksd The value of .

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