Simulation Analysis Method and System for Bolt Strength of Launch Vehicles

Abstract

This invention provides a method and system for simulating and analyzing the strength of bolts in a launch vehicle, comprising: constructing a nonlinear finite element model of the bolt connection and performing finite element simulation to obtain the stress distribution on each cross section of the bolt; calculating the overall tensile stress and shear stress of the bolt's critical cross section based on all resultant forces, moments, effective stress cross-sectional area, and section modulus of the bolt; calculating the equivalent stress of the bolt's critical cross section based on the overall tensile stress and shear stress; calculating the strength residual coefficient of the bolt's overall bearing capacity based on the bolt's ultimate strength and the equivalent stress of the critical cross section; calculating the strength residual coefficient of the bolt considering local stress concentration based on the bolt's ultimate strength and maximum stress value; and taking the smaller value between the strength residual coefficient of the bolt's overall bearing capacity and the strength residual coefficient of the bolt considering local stress concentration as the minimum strength residual coefficient for bolt strength verification.

Description

Technical Field

[0001] This invention relates to the field of bolt strength analysis technology, and more specifically, to a method and system for simulation analysis of bolt strength in launch vehicles. Background Technology

[0002] Current technologies for bolt strength analysis include methods using finite element modeling. The main idea is to obtain the bolt's stress distribution through finite element calculations and directly compare the maximum stress with the bolt's yield strength or ultimate tensile strength to obtain a strength verification result. A drawback of this method is that it only considers the impact of stress concentration on bolt strength based on the stress distribution results. In practice, when performing strength simulations on bolts used in launch vehicles, it's crucial not only to focus on local stress concentrations using stress distribution maps but also to assess the individual load-bearing capacity of each bolt under uneven loading conditions. This is a prerequisite for the bolted connection to fulfill its function. To examine the overall load-bearing capacity of the bolt, it's necessary to extract all resultant forces and moments at the bolt's critical section, comprehensively consider the combination of tension, shear, bending, and torsion, and evaluate the equivalent stress using coupling formulas.

[0003] Therefore, the strength analysis of bolts should be comprehensively considered and evaluated from two dimensions: the overall load-bearing capacity of the bolt and the stress failure caused by stress concentration effect.

[0004] Patent document CN103020377A (application number: 201210575098.4) discloses a bolt strength analysis method for a direct-drive wind turbine, including: (1) performing finite element modeling of the direct-drive wind turbine structure; (2) applying external load to the direct-drive wind turbine structure; (3) calculating and extracting the bolt stress results under the external load; (4) performing post-processing on the extracted bolt stress results; (5) calculating the fatigue strength and ultimate strength of the bolt based on the post-processing results. In step (3), the bolt stress results include the axial stress and two mutually perpendicular bending stress results of the same cross section of the bolt. Correspondingly, in step (4), the post-processing process is to superimpose the three stress components of the axial stress and the two mutually perpendicular bending stresses, and then synthesize the resultant stress according to the maximum principal stress rule. Summary of the Invention

[0005] In view of the deficiencies in the existing technology, the purpose of this invention is to provide a method and system for simulating and analyzing the bolt strength of a launch vehicle.

[0006] A method for simulating and analyzing the bolt strength of a launch vehicle according to the present invention includes: Step S1: Construct a nonlinear finite element model of the bolt connection under the specific application scenario or working condition of the launch vehicle bolts; Step S2: By considering the bolt preload and the design load under the corresponding working conditions of the launch vehicle, finite element simulation is performed based on the nonlinear finite element model of the bolt connection to obtain the stress distribution on each section of the bolt, extract the maximum stress value in the stress concentration area of ​​the bolt, and extract all resultant forces and moments on the dangerous section of the bolt, including: bolt axial force, shear force, torsional moment, and bending moment. Step S3: Calculate the overall tensile and shear stresses at the critical section of the bolt based on all resultant forces and moments at the bolt's critical section, as well as the bolt's effective stress cross-sectional area and section modulus. Step S4: Calculate the equivalent stress at the critical section of the bolt based on the overall tensile and shear stresses at the critical section. Step S5: Calculate the residual strength coefficient of the overall bearing capacity of the bolt by combining the ultimate strength of the bolt with the equivalent stress at the critical section; Step S6: Calculate the residual strength coefficient of the bolt considering local stress concentration based on the bolt's ultimate strength and maximum stress value; Step S7: Taking into account both the overall bearing capacity of the bolt and the local stress concentration of the bolt, the smaller value is taken as the minimum residual strength coefficient for bolt strength verification.

[0007] Preferably, step S3 includes: Step S3.1: Based on the nominal diameter of the bolts used in the launch vehicle With pitch Calculate the effective stress cross-sectional area, torsional section modulus, and bending section modulus of the bolt; The formula for calculating the effective stress cross-sectional area of ​​the bolt is as follows: ; The formula for calculating the torsional section modulus is as follows: ; The formula for calculating the flexural section modulus is: = = ; Step S3.2: Based on the extracted axial force at the critical section of the bolt With the effective stress cross-sectional area of ​​the bolt The axial normal stress at the critical section of the bolt is calculated. The formula for calculating the axial normal stress at the critical section of the bolt is as follows: ; Step S3.3: Based on the extracted shear force at the critical section of the bolt , With the effective stress cross-sectional area of ​​the bolt The transverse shear stress at the critical section of the bolt was calculated. The formula for calculating the transverse shear stress at the critical section of the bolt is as follows: ; Step S3.4: Based on the extracted bending moment of the bolt's critical section... , Section modulus of bolt bending , The bending tensile stress at the critical section of the bolt was calculated. The formula for calculating the bending tensile stress at the critical section of the bolt is as follows: ; Step S3.5: Based on the extracted torsional moment of the bolt's critical section... Section modulus of bolt torsion The torsional shear stress at the critical section of the bolt was calculated. The formula for calculating the torsional shear stress at the critical section of the bolt is as follows: ; Step S3.6: Superimpose axial normal stress With bending tensile stress The total tensile stress at the critical section is obtained; The formula for calculating the total tensile stress at the critical section is: ; Step S3.7: Superimpose transverse shear stress With torsional shear stress The total shear stress at the critical section is obtained; The formula for calculating the overall shear stress at the critical section is as follows: .

[0008] Preferably, the equivalent stress at the critical section of the bolt in step S4 includes:

[0009] in, Equivalent stress at the critical section of the bolt; The total tensile stress at the critical section; The total shear stress at the critical section.

[0010] Preferably, the residual strength coefficient of the overall bearing capacity of the bolt in step S5 includes:

[0011] in, This is the residual strength coefficient for the overall bearing capacity of the bolt; This is the ultimate strength of the bolt; The equivalent stress at the critical section of the bolt.

[0012] Preferably, the residual strength factor for local stress concentration of the bolt in step S6 includes:

[0013] in, The residual strength factor is used to account for stress concentration in local bolt areas. This is the ultimate strength of the bolt; This represents the maximum stress value.

[0014] A simulation analysis system for bolt strength of a launch vehicle provided by the present invention includes: Module M1: Construct a nonlinear finite element model of bolted connections under specific application scenarios or operating conditions of launch vehicle bolts; Module M2: By considering the bolt preload and the design load under the corresponding working conditions of the launch vehicle, finite element simulation is performed based on the nonlinear finite element model of the bolt connection to obtain the stress distribution on each section of the bolt, extract the maximum stress value in the stress concentration area of ​​the bolt, and extract all resultant forces and moments on the dangerous section of the bolt, including: bolt axial force, shear force, torsional moment, and bending moment. Module M3: Calculate the overall tensile and shear stresses at the critical section of the bolt based on all resultant forces and moments at the bolt's critical section, as well as the bolt's effective stress cross-sectional area and section modulus. Module M4: Calculate the equivalent stress at the critical section of the bolt based on the overall tensile and shear stresses at the critical section. Module M5: Calculates the residual strength coefficient of the bolt's overall bearing capacity by combining the bolt's ultimate strength with the equivalent stress at the critical section; Module M6: Calculate the residual strength coefficient of the bolt considering local stress concentration based on the bolt's ultimate strength and maximum stress value; Module M7: The smaller of the two values, which takes into account the overall bearing capacity of the bolt and the local stress concentration of the bolt, is taken as the minimum residual strength coefficient for bolt strength verification.

[0015] Preferably, the module M3 includes: Module M3.1: Based on the nominal diameter of the bolts used in the launch vehicle With pitch Calculate the effective stress cross-sectional area, torsional section modulus, and bending section modulus of the bolt; The formula for calculating the effective stress cross-sectional area of ​​the bolt is as follows: ; The formula for calculating the torsional section modulus is as follows: ; The formula for calculating the flexural section modulus is: = = ; Module M3.2: Based on the extracted axial force at the critical section of the bolt With the effective stress cross-sectional area of ​​the bolt The axial normal stress at the critical section of the bolt is calculated. The formula for calculating the axial normal stress at the critical section of the bolt is as follows: ; Module M3.3: Based on the extracted shear force at the critical section of the bolt. , With the effective stress cross-sectional area of ​​the bolt The transverse shear stress at the critical section of the bolt was calculated. The formula for calculating the transverse shear stress at the critical section of the bolt is as follows: ; Module M3.4: Based on the extracted bending moment of the bolt's critical section , Section modulus of bolt bending , The bending tensile stress at the critical section of the bolt was calculated. The formula for calculating the bending tensile stress at the critical section of the bolt is as follows: ; Module M3.5: Based on the extracted torsional moment of the bolt's critical section. Section modulus of bolt torsion The torsional shear stress at the critical section of the bolt was calculated. The formula for calculating the torsional shear stress at the critical section of the bolt is as follows: ; Module M3.6: Superimposed axial normal stress With bending tensile stress The total tensile stress at the critical section is obtained; The formula for calculating the total tensile stress at the critical section is: ; Module M3.7: Superimposed transverse shear stress With torsional shear stress The total shear stress at the critical section is obtained; The formula for calculating the overall shear stress at the critical section is as follows: .

[0016] Preferably, the equivalent stress at the critical section of the bolt in module M4 includes:

[0017] in, Equivalent stress at the critical section of the bolt; The total tensile stress at the critical section; The total shear stress at the critical section.

[0018] Preferably, the residual strength coefficient of the overall bearing capacity of the bolts in module M5 includes:

[0019] in, This is the residual strength coefficient for the overall bearing capacity of the bolt; This is the ultimate strength of the bolt; The equivalent stress at the critical section of the bolt.

[0020] Preferably, the residual strength factor for local stress concentration of the bolts in module M6 includes:

[0021] in, The residual strength factor is used to account for stress concentration in local bolt areas. This is the ultimate strength of the bolt; This represents the maximum stress value.

[0022] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention uses a nonlinear finite element method to accurately model bolts, creating a bolt solid model, establishing the contact relationship between the bolt and the connected parts, and applying a preload to the bolt. This solves the problems of fully considering the influence of bolt preload on bolt tensile deformation and the influence of friction behavior generated by preload on bolt shear force in bolt strength analysis. 2. This invention accurately obtains all resultant forces and moments on the critical section of the bolt through finite element analysis, and calculates the overall tensile stress and shear stress of the critical section. It solves the problem of how to perform bolt strength analysis under complex working conditions of tension, shear, bending and torsion. It not only considers tensile force and shear force, but also takes into account the tensile stress and shear stress generated by bending moment and torsional moment, which further improves the accuracy of bolt strength analysis. 3. This invention solves the one-sided problem of previous bolt strength simulations that only considered the bolt stress distribution by comprehensively examining the overall bearing capacity of the bolt and the local stress concentration effect. Through finite element analysis results, the resultant force and moment of the cross section are obtained, the overall tensile stress and shear stress are calculated, and the equivalent stress considering the combination of tension, shear, bending and torsion is synthesized, thereby examining the overall bearing capacity of the bolt. 4. This invention obtains a stress distribution map through finite element stress analysis, extracts the maximum stress in the stress concentration area, and examines the influence of stress concentration on bolt strength. Attached Figure Description

[0023] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a flowchart of the simulation analysis method for bolt strength of a launch vehicle. Detailed Implementation

[0024] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0025] Example 1 According to the present invention, a method and system for simulating and analyzing the strength of launch vehicle bolts is provided. By constructing a nonlinear finite element model of bolt connection considering bolt body, contact friction and bolt preload, the method calculates and extracts all resultant forces, moments and stress distributions of the bolt critical section. By comprehensively considering the overall bearing capacity and local stress concentration effect of the bolt, the method achieves accurate simulation prediction and evaluation of the strength of launch vehicle bolts under complex loading conditions.

[0026] The simulation analysis method for the bolt strength of the launch vehicle, such as Figure 1 As shown, it includes: Step 1: Under the specific application scenario or working condition of the launch vehicle bolts, construct a nonlinear finite element model of the bolt connection, including the bolt solid model, the nonlinear mechanical behavior such as contact and friction between the bolt and the connected parts, and consider the nonlinearity of bolt material parameters and the nonlinearity of geometric deformation.

[0027] Step 2: Simultaneously consider the bolt preload and the design load under the corresponding working conditions of the launch vehicle, perform nonlinear finite element model simulation of the bolt connection, and obtain the finite element simulation results.

[0028] Step 3: Based on the finite element simulation results, examine the stress distribution on each cross-section of the bolt, and extract all resultant forces and moments on the critical cross-section of the bolt, including the bolt axial force. Shear force , Torsional moment Bending moment , wait.

[0029] Step 4: Based on the resultant forces and moments at the critical section of the bolt, and the effective stress cross-sectional area of ​​the bolt. and section modulus Calculate the total tensile stress at the critical section of the bolt using parameters such as... With shear stress .

[0030] Specifically, step 4 includes: Step 4.1: Based on the nominal diameter of the bolts used in the launch vehicle With pitch Calculate the effective stress cross-sectional area of ​​the bolt using parameters such as... Torsional section modulus Section modulus of bending = = wait; Step 4.2: Based on the extracted axial force at the critical section of the bolt With the effective stress cross-sectional area of ​​the bolt The axial normal stress at the critical section of the bolt was calculated. ; Step 4.3: Based on the extracted shear force at the critical section of the bolt , With the effective stress cross-sectional area of ​​the bolt The transverse shear stress at the critical section of the bolt was calculated. ; Step 4.4: Based on the extracted bending moment of the bolt's critical section , Section modulus of bolt bending , The bending tensile stress at the critical section of the bolt was calculated. ; Step 4.5: Based on the extracted torsional moment of the bolt's critical section Section modulus of bolt torsion The torsional shear stress at the critical section of the bolt was calculated. ; Step 4.6: Superimpose the axial normal stress obtained in Step 4.2 The bending tensile stress obtained in step 4.4 The total tensile stress at the critical section is obtained. ; Step 4.7: Superimpose the transverse shear stress obtained in Step 4.3 The torsional shear stress obtained in step 4.5 The total shear stress at the critical section is obtained. .

[0031] Step 5: Calculate the total tensile stress at the critical section of the bolt. With shear stress Considering the combined load conditions of bolt tension, shear, bending, and torsion, the equivalent stress at the critical section of the bolt is calculated based on the coupled calculation formula for combined load conditions. .

[0032] Step 6: Set the bolt strength limit Equivalent stress at the critical section By comparison, the residual strength coefficient of the overall bearing capacity of the bolt is obtained. .

[0033] Step 7: Based on the finite element analysis results, extract the maximum stress value in the stress concentration region of the bolt. .

[0034] Step 8: Set the bolt strength limit With maximum stress value By comparison, the residual strength coefficient of the bolt considering local stress concentration is obtained. .

[0035] Step 9: Taking into account the residual coefficient of overall bolt bearing strength obtained in Step 6 The residual strength coefficient of the bolt considering local stress concentration obtained in step 8 The smaller of the two values ​​is taken as the minimum residual strength coefficient for bolt strength verification. .

[0036] The present invention also provides a bolt strength simulation analysis system for launch vehicles. The bolt strength simulation analysis system for launch vehicles can be implemented by executing the process steps of the bolt strength simulation analysis method for launch vehicles. That is, those skilled in the art can understand the bolt strength simulation analysis method for launch vehicles as a preferred embodiment of the bolt strength simulation analysis system for launch vehicles.

[0037] Those skilled in the art will understand that, in addition to implementing the system, apparatus, and their modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and their modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.

[0038] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for simulating and analyzing the strength of bolts in a launch vehicle, characterized in that, include: Step S1: Construct a nonlinear finite element model of the bolt connection under the specific application scenario or working condition of the launch vehicle bolts; Step S2: By considering the bolt preload and the design load under the corresponding working conditions of the launch vehicle, finite element simulation is performed based on the nonlinear finite element model of the bolt connection to obtain the stress distribution on each section of the bolt, extract the maximum stress value in the stress concentration area of ​​the bolt, and extract all resultant forces and moments on the dangerous section of the bolt, including: bolt axial force, shear force, torsional moment, and bending moment. Step S3: Calculate the overall tensile and shear stresses at the critical section of the bolt based on all resultant forces and moments at the bolt's critical section, as well as the bolt's effective stress cross-sectional area and section modulus. Step S4: Calculate the equivalent stress at the critical section of the bolt based on the overall tensile and shear stresses at the critical section. Step S5: Calculate the residual strength coefficient of the overall bearing capacity of the bolt by combining the ultimate strength of the bolt with the equivalent stress at the critical section; Step S6: Calculate the residual strength coefficient of the bolt considering local stress concentration based on the bolt's ultimate strength and maximum stress value; Step S7: Taking into account both the overall bearing capacity of the bolt and the local stress concentration of the bolt, the smaller value is taken as the minimum residual strength coefficient for bolt strength verification.

2. The method for simulating and analyzing the bolt strength of a launch vehicle according to claim 1, characterized in that, Step S3 includes: Step S3.1: Based on the nominal diameter of the bolts used in the launch vehicle With pitch Calculate the effective stress cross-sectional area, torsional section modulus, and bending section modulus of the bolt; The formula for calculating the effective stress cross-sectional area of ​​the bolt is as follows: ； The formula for calculating the torsional section modulus is: ； The formula for calculating the flexural section modulus is: = = ； Step S3.2: Based on the extracted axial force at the critical section of the bolt With the effective stress cross-sectional area of ​​the bolt The axial normal stress at the critical section of the bolt is calculated. The formula for calculating the axial normal stress at the critical section of the bolt is as follows: ； Step S3.3: Based on the extracted shear force at the critical section of the bolt , With the effective stress cross-sectional area of ​​the bolt The transverse shear stress at the critical section of the bolt was calculated. The formula for calculating the transverse shear stress at the critical section of the bolt is as follows: ； Step S3.4: Based on the extracted bending moment of the bolt's critical section... , Section modulus of bolt bending , The bending tensile stress at the critical section of the bolt was calculated. The formula for calculating the bending tensile stress at the critical section of the bolt is as follows: ； Step S3.5: Based on the extracted torsional moment of the bolt's critical section... Section modulus of bolt torsion The torsional shear stress at the critical section of the bolt was calculated. The formula for calculating the torsional shear stress at the critical section of the bolt is as follows: ； Step S3.6: Superimpose axial normal stress With bending tensile stress The total tensile stress at the critical section is obtained; The formula for calculating the total tensile stress at the critical section is: ； Step S3.7: Superimpose transverse shear stress With torsional shear stress The total shear stress at the critical section is obtained; The formula for calculating the overall shear stress at the critical section is as follows: 。 3. The method for simulating and analyzing the bolt strength of a launch vehicle according to claim 1, characterized in that, The equivalent stress at the critical section of the bolt in step S4 includes: in, Equivalent stress at the critical section of the bolt; The total tensile stress at the critical section; The total shear stress at the critical section.

4. The method for simulating and analyzing the bolt strength of a launch vehicle according to claim 1, characterized in that, The residual strength coefficient of the overall bearing capacity of the bolt in step S5 includes: in, This is the residual strength coefficient for the overall bearing capacity of the bolt; This is the ultimate strength of the bolt; The equivalent stress at the critical section of the bolt.

5. The method for simulating and analyzing the bolt strength of a launch vehicle according to claim 1, characterized in that, The residual strength factor for considering local stress concentration in the bolt in step S6 includes: in, The residual strength factor is used to account for stress concentration in local bolt areas. This is the ultimate strength of the bolt; This represents the maximum stress value.

6. A simulation analysis system for bolt strength of a launch vehicle, characterized in that, include: Module M1: Construct a nonlinear finite element model of bolted connections under specific application scenarios or operating conditions of launch vehicle bolts; Module M2: By considering the bolt preload and the design load under the corresponding working conditions of the launch vehicle, finite element simulation is performed based on the nonlinear finite element model of the bolt connection to obtain the stress distribution on each section of the bolt, extract the maximum stress value in the stress concentration area of ​​the bolt, and extract all resultant forces and moments on the dangerous section of the bolt, including: bolt axial force, shear force, torsional moment, and bending moment. Module M3: Calculate the overall tensile and shear stresses at the critical section of the bolt based on all resultant forces and moments at the bolt's critical section, as well as the bolt's effective stress cross-sectional area and section modulus. Module M4: Calculate the equivalent stress at the critical section of the bolt based on the overall tensile and shear stresses at the critical section. Module M5: Calculates the residual strength coefficient of the bolt's overall bearing capacity by combining the bolt's ultimate strength with the equivalent stress at the critical section; Module M6: Calculate the residual strength coefficient of the bolt considering local stress concentration based on the bolt's ultimate strength and maximum stress value; Module M7: The smaller of the two values, which takes into account the overall bearing capacity of the bolt and the local stress concentration of the bolt, is taken as the minimum residual strength coefficient for bolt strength verification.

7. The bolt strength simulation analysis system for launch vehicles according to claim 6, characterized in that, The module M3 includes: Module M3.1: Based on the nominal diameter of the bolts used in the launch vehicle With pitch Calculate the effective stress cross-sectional area, torsional section modulus, and bending section modulus of the bolt; The formula for calculating the effective stress cross-sectional area of ​​the bolt is as follows: ； The formula for calculating the torsional section modulus is: ； The formula for calculating the flexural section modulus is: = = ； Module M3.2: Based on the extracted axial force at the critical section of the bolt With the effective stress cross-sectional area of ​​the bolt The axial normal stress at the critical section of the bolt is calculated. The formula for calculating the axial normal stress at the critical section of the bolt is as follows: ； Module M3.3: Based on the extracted shear force at the critical section of the bolt. , With the effective stress cross-sectional area of ​​the bolt The transverse shear stress at the critical section of the bolt was calculated. The formula for calculating the transverse shear stress at the critical section of the bolt is as follows: ； Module M3.4: Based on the extracted bending moment of the bolt's critical section , Section modulus of bolt bending , The bending tensile stress at the critical section of the bolt was calculated. The formula for calculating the bending tensile stress at the critical section of the bolt is as follows: ； Module M3.5: Based on the extracted torsional moment of the bolt's critical section. Section modulus of bolt torsion The torsional shear stress at the critical section of the bolt was calculated. The formula for calculating the torsional shear stress at the critical section of the bolt is as follows: ； Module M3.6: Superimposed axial normal stress With bending tensile stress The total tensile stress at the critical section is obtained; The formula for calculating the total tensile stress at the critical section is: ； Module M3.7: Superimposed transverse shear stress With torsional shear stress The total shear stress at the critical section is obtained; The formula for calculating the overall shear stress at the critical section is as follows: 。 8. The bolt strength simulation analysis system for launch vehicles according to claim 6, characterized in that, The equivalent stress at the critical section of the bolt in module M4 includes: in, Equivalent stress at the critical section of the bolt; The total tensile stress at the critical section; The total shear stress at the critical section.

9. The bolt strength simulation analysis system for launch vehicles according to claim 6, characterized in that, The residual strength coefficient of the overall bearing capacity of the bolts in module M5 includes: in, This is the residual strength coefficient for the overall bearing capacity of the bolt; This is the ultimate strength of the bolt; The equivalent stress at the critical section of the bolt.

10. The bolt strength simulation analysis system for launch vehicles according to claim 6, characterized in that, The residual strength factor for bolts in module M6, considering local stress concentration, includes: in, The residual strength factor is used to account for stress concentration in local bolt areas. This is the ultimate strength of the bolt; This represents the maximum stress value.

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