High-strength steel welding seam strength numerical simulation method, system, equipment and medium

Abstract

The invention discloses a high-strength steel weld strength numerical simulation method, system, equipment and medium, and relates to the technical field of welding numerical analysis, and the method comprises the following steps: obtaining a high-strength steel welded joint finite element model, and carrying out welding heat conduction analysis on the high-strength steel welded joint finite element model through a heat source model to obtain a high-strength steel welded joint finite element model; obtaining temperature field data in the high-strength steel welding process; the temperature field data are applied to the high-strength steel welding joint finite element model, and the peak temperature and the cooling time of a welding heat affected zone are extracted; material attributes of high-strength steel under different welding heat cycle conditions are obtained, the relation between the material attributes and the welding heat cycle peak temperature and the relation between the material attributes and the cooling time are established through field variables, corresponding welding heat affected zones are given to the material attributes, post-welding mechanical analysis is conducted, and a stress-strain curve of a high-strength steel welding joint is obtained. The method provided by the invention can fully consider the influence of the welding heat cycle on the properties of the high-strength steel material, and accurately obtain the damage mode of the high-strength steel.

Description

Technical Field

[0001] The present invention relates to the technical field of welding numerical analysis, and particularly relates to a method, system, device and medium for numerical simulation of high-strength steel weld strength. Background Art

[0002] Due to its comprehensive advantages such as high strength, low cost, low carbon and environmental protection, high-strength steel has great application prospects in steel structure engineering. However, when welded connections are used, high-strength steel is extremely sensitive to welding heat input due to its relatively high carbon equivalent and more alloying elements. A high welding heat input will seriously reduce the strength of the material in the heat-affected zone. At the same time, the base metal near the heat-affected zone of the welded joint will also show strength degradation, i.e., softening phenomenon, due to the welding heat cycle, making the actual strength of the welded joint significantly lower than the design value. Therefore, it is crucial to fully consider the influence of the material softening effect when designing the weld.

[0003] Currently, the research on high-strength steel weld strength mainly includes experimental methods and finite element simulation methods. The experimental method mainly obtains the stress-strain curve by conducting standard tensile tests on the base metal, welding consumables, and welded joints, so as to study the mechanical properties of high-strength steel welds. However, the experimental method can only obtain the overall mechanical properties and cannot accurately evaluate the true mechanical properties of the welding heat-affected zone. Moreover, if the welding process is improper during welding, the introduced welding cracks will also affect the accuracy of the measurement results.

[0004] It can be seen that the existing finite element simulation method mainly obtains the mechanical properties of weld strength through heat conduction analysis, thermo-mechanical coupling analysis, and post-weld mechanical analysis. Although this method can simulate the mechanical properties of the weld, it ignores the material softening effect caused by welding heat and a series of influences brought about by the material softening effect, and cannot truly simulate the mechanical properties of the weld, resulting in inaccurate simulation results. Summary of the Invention

[0005] The purpose of the present invention is to provide a method, system, device and medium for numerical simulation of high-strength steel weld strength in view of the above-mentioned deficiencies of the prior art, so as to solve the problems in the prior art.

[0006] The present invention specifically provides the following technical solutions:

[0007] A method for numerical simulation of high-strength steel weld strength, comprising:

[0008] Construct a finite element model of a high-strength steel welded joint, and perform welding heat conduction analysis on the finite element model of the high-strength steel welded joint through a heat source model to obtain temperature field data during the high-strength steel welding process;

[0009] Apply the temperature field data to the replicated finite element model of the high-strength steel welded joint, analyze the residual stress of the high-strength steel welded joint by using the sequential thermal-mechanical coupling method, and extract the peak temperature and cooling time corresponding to the welding heat-affected zone of the residual stress of the high-strength steel welded joint;

[0010] Obtain the material properties of high-strength steel under different welding thermal cycles, establish the relationship between the material properties and the peak temperature and cooling time under the welding thermal cycle by introducing field variables, and based on the relationship, assign the material properties affected by the welding thermal cycle to the corresponding welding heat-affected zone and conduct post-weld mechanical analysis to obtain the stress-strain curve and weld strength of the high-strength steel welded joint.

[0011] Preferably, the welding heat conduction analysis of the finite element model of the high-strength steel welded joint is carried out by using the heat source model to obtain the temperature field data of the high-strength steel welding process, specifically: set two analysis steps of welding heating and cooling, and obtain the temperature field data of the high-strength steel welding process through the two analysis steps.

[0012] Preferably, the heat source model is a three-dimensional double-ellipsoid heat source model, and the three-dimensional double-ellipsoid heat source model is specifically:

[0013] The calculation formula of the heat flux distribution function q 1 (x, y, z) of the front half ellipsoid in the three-dimensional double-ellipsoid heat source model is:

[0014]

[0015] The calculation formula of the heat flux distribution function q 2 (x, y, z) of the rear half ellipsoid in the three-dimensional double-ellipsoid heat source model is:

[0016]

[0017] Where: Q = ηUI, Q is the total welding power, η is the thermal efficiency coefficient, U is the welding voltage, and I is the welding current; x is the distance in the welding direction from the heat source center, y is the distance in the weld width direction from the heat source center, and z is the distance in the weld depth direction from the heat source center; a 1 and a 2 are the geometric dimensions of the molten pool; b and c are the weld width dimension and weld depth dimension respectively; f 1 and f 2 are the ellipsoidal heat source distribution parameters, satisfying f 1 + f 2 = 2.

[0018] Preferably, after obtaining the temperature field data of the high-strength steel welding process, it further includes:

[0019] Compare and analyze the temperature field data of the high-strength steel welding process with the test temperature field data, and adjust the heat source model parameters based on the deviation of the comparison and analysis results;

[0020] When adjusting the heat source model parameters, repeat the welding heat conduction analysis multiple times until the error between the molten pool boundary simulated by the heat source model and the actual welding molten pool boundary is less than the threshold, and obtain the temperature of the temperature field of the optimal simulated welding.

[0021] Preferably, the peak temperature and cooling time of the welding heat-affected zone respectively refer to the highest temperature and time t experienced by the welding heat-affected zone during the welding process 8 / 5 where the time t 8 / 5 represents the time required for the temperature of the welding heat-affected zone to drop from 800 °C to 500 °C.

[0022] Preferably, the material properties of the high-strength steel under different welding heat cycle conditions are the stress-strain curves obtained from the thermal influence specimen material property tests.

[0023] The present invention provides a high-strength steel weld strength numerical simulation system, including:

[0024] A heat conduction module for constructing a finite element model of a high-strength steel welded joint and performing welding heat conduction analysis on the finite element model of the high-strength steel welded joint through a heat source model to obtain the temperature field data of the high-strength steel welding process;

[0025] An extraction module for applying the temperature field data to the replicated finite element model of the high-strength steel welded joint, analyzing the residual stress of the high-strength steel welded joint by using the sequential thermal-mechanical coupling method, and extracting the peak temperature and cooling time of the welding heat-affected zone corresponding to the residual stress of the high-strength steel welded joint;

[0026] An analysis module for obtaining the material properties of the high-strength steel under different welding heat cycle conditions, establishing the relationship between the material properties and the peak temperature and cooling time under the welding heat cycle conditions by introducing field variables, and based on the relationship, assigning the material properties affected by the welding heat cycle to the corresponding welding heat-affected zone and performing post-weld mechanical analysis to obtain the stress-strain curve and weld strength of the high-strength steel welded joint.

[0027] The present invention provides a computer device, including a memory and a processor. When a program stored in the memory is executed by the processor, the processor executes the steps of the above-mentioned high-strength steel weld strength numerical simulation method.

[0028] The present invention provides a storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned high-strength steel weld strength numerical simulation method are implemented.

[0029] Compared with the prior art, the present invention has the following remarkable advantages:

[0030] During the welding process, the thermal cycle experienced by the material in the heat-affected zone will change the material properties of high-strength steel. The method of the present invention uses a heat source model for welding heat conduction to obtain the temperature field data of the high-strength steel welding process, and applies the temperature field data to the finite element model of the high-strength steel welding joint, extracts the peak temperature and cooling temperature corresponding to the residual stress of the high-strength steel welding joint in the heat-affected zone, lays a foundation for the next mechanical analysis of the welding joint, and establishes the relationship between the material properties and the peak temperature and cooling temperature to obtain the change relationship between the high-strength steel material properties and the thermal cycle process, further improving the accuracy of the mechanical analysis results during the welding process. Finally, the material properties affected by the welding thermal cycle are assigned to the corresponding heat-affected zone, and the post-weld mechanical analysis is carried out to obtain the stress-strain curve and weld strength of the high-strength steel welding joint, realizing the full consideration of the influence of the welding thermal cycle on the material properties of high-strength steel and accurately obtaining the stress-strain curve and failure mode of the high-strength steel welding joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is an analysis flow chart of a numerical simulation method for high-strength steel weld strength in an embodiment of the present invention;

[0032] Figure 2 It is a comparison chart of the temperature history data of the high-strength steel welding joint of the present invention;

[0033] Figure 3 It is a comparison chart of the stress-strain curves of the high-strength steel welding joint of the present invention;

[0034] Figure 4 It is a comparison chart of the finite element analysis failure modes of the high-strength steel welding joint in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] Referring to the attached Figure 1 , a numerical simulation method for high-strength steel weld strength in this embodiment includes the following steps:

[0037] Step S1: Construct a finite element model of the high-strength steel welding joint, and perform welding heat conduction analysis on the finite element model of the high-strength steel welding joint through a heat source model to obtain the temperature field data of the high-strength steel welding process.

[0038] In one embodiment, the finite element software ABAQUS is used to establish a finite element model of a 6-mm welded joint of Q690 steel.

[0039] The welding heat conduction analysis of the finite element model of the high-strength steel welded joint is carried out through a heat source model to obtain the temperature field data during the welding process of high-strength steel. Specifically, two analysis steps of welding heating and cooling are set, and the types of both analysis steps are Heattransfer (Transient). The temperature field data during the welding process of high-strength steel are obtained through the analysis of these two analysis steps. To ensure the calculation accuracy, the grids in the weld and the near-weld zone of the butt joint model need to be encrypted, with a grid size of 1 mm. The grids in the area far from the weld can be appropriately increased to reduce the calculation amount, with a grid size of 2 mm. The element type of the grid in the welding heat-affected zone is DC3D8.

[0040] The heat source model is a three-dimensional double-ellipsoid heat source model, and the three-dimensional double-ellipsoid heat source model is specifically:

[0041] In the three-dimensional double-ellipsoid heat source model, the calculation formula of the heat flux distribution function q 1 (x, y, z) of the front half-ellipsoid is:

[0042]

[0043] In the three-dimensional double-ellipsoid heat source model, the calculation formula of the heat flux distribution function q 2 (x, y, z) of the rear half-ellipsoid is:

[0044]

[0045] Where: Q = ηUI, Q is the total welding power, η is the heat efficiency coefficient, U is the welding voltage, and I is the welding current; x is the distance in the welding direction from the heat source center, y is the distance in the weld width direction from the heat source center, and z is the distance in the weld depth direction from the heat source center; a 1 and a 2 are the geometric dimensions of the molten pool; b and c are the weld width dimension and the weld depth dimension respectively; f 1 and f 2 are the ellipsoid heat source distribution parameters, satisfying f 1 + f 2 = 2.

[0046] The welding parameters selected in this embodiment are: welding heat efficiency η = 0.90, welding voltage U = 30 V, welding current I = 600 A, welding speed v = 7.5 mm / s, and welding heat input is 2.16 kJ / mm.

[0047] After obtaining the temperature field data during the welding process of high-strength steel, it further includes:

[0048] To ensure that the temperature field simulation during the welding process conforms to the actual welding situation, heat source calibration is required. The temperature field data of the high-strength steel welding process is compared and analyzed with the experimental temperature field data, and the heat source model parameters are adjusted based on the deviation of the comparison and analysis results.

[0049] When adjusting the heat source model parameters, the welding heat conduction analysis is repeated multiple times until the error between the molten pool boundary simulated by the heat source model and the actual welding molten pool boundary is less than the threshold value, and the temperature of the temperature field for the optimal simulated welding is obtained. Figure 2 For the time history curve of the measured point temperature obtained from the welding experiment and the time history curve of the temperature at the same measured point in the finite element model, it can be observed that the simulation results are in good agreement with the experimental results, indicating that the temperature field results obtained by the simulation are accurate.

[0050] Step S2: Apply the temperature field data to the replicated finite element model of the high-strength steel welded joint, analyze the residual stress of the high-strength steel welded joint using the sequential thermal-mechanical coupling method, and use the UEXPAN user subroutine to extract the peak temperature and cooling time of the welding heat affected zone elements corresponding to the residual stress of the high-strength steel welded joint.

[0051] The peak temperature and cooling time of the welding heat affected zone elements respectively refer to the highest temperature and time t experienced by the welding heat affected zone elements during the welding process 8 / 5 , where the time t 8 / 5 represents the time required for the temperature of the welding heat affected zone elements to drop from 800 °C to 500 °C.

[0052] In ABAQUS, using the sequential thermal-mechanical coupling method, the temperature field data obtained from the heat conduction analysis is applied to the replicated finite element model of the high-strength steel welded joint in the form of a temperature load. The thermal strain of the welding heat affected zone elements is obtained through sequential thermal-mechanical coupling analysis, and then the corresponding welding residual stress is obtained. The model used in the sequential thermal-mechanical coupling analysis is directly modified based on the replicated heat conduction analysis model. In the welding residual stress analysis, the UEXPAN user subroutine is used to extract the peak temperature and cooling time during the heating and cooling processes in the heat conduction analysis of the welding heat affected zone elements, laying a foundation for the next mechanical analysis of the welded joint.

[0053] Step S3: Obtain the material properties of high-strength steel under different welding thermal cycle conditions. Based on the material properties, use the USDFLD user subroutine to establish the relationship between the material properties and the peak temperature and cooling time under the welding thermal cycle conditions by introducing field variables. Based on the relationship, assign the material properties affected by the welding thermal cycle to the corresponding welding heat affected zone elements, and perform post-weld mechanical analysis to obtain the stress-strain curve and weld strength of the high-strength steel welded joint.

[0054] Using the UEXPAN user subroutine and the USDFLD user subroutine, the material properties affected by different welding thermal cycles are assigned to the corresponding units in the weld heat affected zone to consider the influence of welding heat input on the mechanical properties of high-strength steel welded joints.

[0055] The material properties of high-strength steel under different welding thermal cycles are the stress-strain curves obtained from the material property (mechanical property) tests of the heat-affected specimens. The weld strength is obtained through the stress-strain curves.

[0056] In this embodiment, a specific welding thermal cycle (heating and cooling process) is applied to the dog-bone tensile specimen using a thermal simulation machine, and the stress-strain curves of Q690 high-strength steel at peak temperatures of 800°C, 1050°C, and 1320°C and cooling times of 15 s, 25 s, and 50 s are obtained. The stress-strain curves are input into the material property module of the finite element model. When inputting, two field variables are introduced, corresponding to the peak temperature and the cooling time respectively. The USDFLD user subroutine is used to establish the relationship between the material properties of high-strength steel and the peak temperature and cooling time of the units in the weld heat affected zone in step 3, and the material properties affected by the welding thermal cycle are assigned to the corresponding units in the weld heat affected zone during the analysis. Subsequently, the post-weld mechanical calculation and analysis are continued, the boundary conditions and loading methods are defined, and finally the stress-strain curve of the high-strength steel welded joint is obtained, thereby obtaining the weld strength.

[0057] The calculation results of the model are compared and analyzed with the test results, and the model is applied to specimens with different welding parameters to verify the accuracy of the simulation method.

[0058] Figure 3 It is a comparison chart of the stress-strain curves of high-strength steel welded joints. Figure 4 It is a comparison chart of the failure modes of the finite element analysis of high-strength steel welded joints. Through analysis, it can be observed that the simulation results fit well with the test results, verifying the accuracy of this method.

[0059] Based on the above method, the present invention provides a numerical simulation system for the weld strength of high-strength steel, including: a heat conduction module, an extraction module, and an analysis module.

[0060] Among them, the heat conduction module is used to construct a finite element model of a high-strength steel welded joint, and perform welding heat conduction analysis on the finite element model of the high-strength steel welded joint through a heat source model to obtain temperature field data during the high-strength steel welding process; the extraction module is used to apply the temperature field data to the replicated finite element model of the high-strength steel welded joint, analyze the residual stress of the high-strength steel welded joint by using the sequential thermal-mechanical coupling method, and extract the peak temperature and cooling time of the welding heat-affected zone unit corresponding to the residual stress of the high-strength steel welded joint; the analysis module is used to obtain the material properties of high-strength steel under different welding thermal cycle conditions, establish the relationship between the material properties and the peak temperature and cooling time under the welding thermal cycle conditions by introducing field variables, and based on the relationship, assign the material properties affected by the welding thermal cycle to the corresponding welding heat-affected zone units, and perform post-weld mechanical analysis to obtain the stress-strain curve and weld strength of the high-strength steel welded joint.

[0061] The present invention also provides a computer device, including a memory and a processor. When a program stored in the memory is executed by the processor, the processor executes the steps of a numerical simulation method for the weld strength of high-strength steel.

[0062] According to the disclosed embodiments, the computer device can communicate with one or more external devices (such as a keyboard, a pointing device, Bluetooth communication, etc.), or communicate with any device (such as a router, a demodulator, etc.) that enables the computing device to communicate with one or more other computing devices.

[0063] The present invention also provides a storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of a numerical simulation method for the weld strength of high-strength steel are implemented.

[0064] According to the disclosed embodiments, the storage medium can be a non-volatile computer-readable storage medium, for example, it can include but is not limited to: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, the storage medium can be any tangible medium that contains or stores a program, and the program can be used by or in combination with an instruction execution system, device, or device.

[0065] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for numerical simulation of high-strength steel weld strength, characterized in that: include: Construct a finite element model of a high-strength steel welded joint, and use a heat source model to analyze the welding heat conduction of the finite element model of the high-strength steel welded joint to obtain the temperature field data of the high-strength steel welding process; The temperature field data was applied to the replicated finite element model of the high-strength steel welded joint, and the residual stress of the high-strength steel welded joint was analyzed using the sequential thermal-mechanical coupling method. The peak temperature and cooling time of the welding heat-affected zone corresponding to the residual stress of the high-strength steel welded joint were extracted. The material properties of high-strength steel under different welding thermal cycle conditions are obtained, and the relationship between the material properties and the peak temperature and cooling time under the welding thermal cycle conditions is established by introducing field variables. Based on the relationship, the material properties under the influence of the welding thermal cycle are assigned to the corresponding welding heat affected zone, and post-weld mechanical analysis is performed to obtain the stress-strain curve and weld strength of the high-strength steel welded joint.

2. A high-strength steel weld strength numerical simulation method according to claim 1, characterized in that: The welding heat conduction analysis of the finite element model of the high-strength steel welded joint is performed through a heat source model to obtain the temperature field data of the high-strength steel welding process, specifically: two analysis steps of welding heating and cooling are set, and the temperature field data of the high-strength steel welding process is obtained through the two analysis steps.

3. A high-strength steel weld strength numerical simulation method as claimed in claim 1, characterized in that: The heat source model is a three-dimensional double ellipsoid heat source model, wherein the three-dimensional double ellipsoid heat source model is specifically: The calculation formula q1(x, y, z) for the heat flux distribution function of the front half ellipsoid in the three-dimensional double ellipsoid heat source model is: The calculation formula q2(x, y, z) for the heat flux distribution function of the rear half ellipsoid in the three-dimensional double ellipsoid heat source model is: Where: Q = ηUI, Q is the total welding power, η is the thermal efficiency coefficient, U is the welding voltage, and I is the welding current; x is the distance from the center of the heat source in the welding direction, y is the distance from the center of the heat source in the direction of the melt width, and z is the distance from the center of the heat source in the direction of the melt depth; a1 and a2 are the geometric dimensions of the molten pool; b and c are the dimensions of the melt width and melt depth, respectively; f1 and f2 are the ellipsoidal heat source distribution parameters, satisfying f1+f2=2.

4. A high-strength steel weld strength numerical simulation method as claimed in claim 1, characterized in that: After obtaining the temperature field data of the high-strength steel welding process, the method further includes: Comparing and analyzing the temperature field data of the high-strength steel welding process with the test temperature field data, and adjusting the heat source model parameters according to the deviation of the comparative analysis results; When adjusting the heat source model parameters, the welding heat conduction analysis is repeated many times until the error between the molten pool boundary simulated by the heat source model and the actual welding molten pool boundary is less than a threshold value, and the temperature of the temperature field for the best simulated welding is obtained.

5. A high-strength steel weld strength numerical simulation method as claimed in claim 1, characterized in that: The peak temperature and cooling time of the welding heat affected zone refer to the highest temperature and time t experienced by the welding heat affected zone during the welding process. 8 / 5 , where time t 8 / 5 It indicates the time required for the temperature of the heat affected zone of welding to drop from 800℃ to 500℃.

6. A high-strength steel weld strength numerical simulation method as claimed in claim 1, characterized in that: The material properties of the high-strength steel under different welding thermal cycle conditions are stress-strain curves obtained from heat-affected specimen material tests.

7. A high-strength steel weld strength numerical simulation system, characterized in that: include: Heat conduction module, which is used to construct the finite element model of high-strength steel welded joints, and to perform welding heat conduction analysis on the finite element model of high-strength steel welded joints through the heat source model to obtain the temperature field data of the high-strength steel welding process; The extraction module is used to apply the temperature field data to the finite element model of the high-strength steel welded joint, analyze the residual stress of the high-strength steel welded joint using the sequential thermal-mechanical coupling method, and extract the peak temperature and cooling time of the welding heat-affected zone corresponding to the residual stress of the high-strength steel welded joint; The analysis module is used to obtain the material properties of high-strength steel under different welding thermal cycle conditions, and establish the relationship between the material properties and the peak temperature and cooling time under the welding thermal cycle conditions through the introduced field variables. Based on the relationship, the material properties under the influence of the welding thermal cycle are assigned to the corresponding welding heat-affected zone, and post-weld mechanical analysis is performed to obtain the stress-strain curve and weld strength of the high-strength steel welded joint.

8. A computer device, characterized in that: It comprises a memory and a processor, wherein a program is stored in the memory, and when the program is executed by the processor, the processor executes the steps of a high-strength steel weld strength numerical simulation method as claimed in any one of claims 1 to 6.

9. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a high-strength steel weld strength numerical simulation method described in any one of claims 1 to 6 are implemented.

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