A method, system, equipment and medium for numerical simulation of high-strength steel weld strength

Abstract

The present invention discloses a method, system, device, and medium for numerical simulation of high-strength steel weld strength, relating to the field of welding numerical analysis technology. The method comprises the following steps: obtaining a finite element model of a high-strength steel weld joint, and performing welding heat conduction analysis on the finite element model of the high-strength steel weld joint using a heat source model to obtain temperature field data of the high-strength steel welding process; applying the temperature field data to the finite element model of the high-strength steel weld joint to extract the peak temperature and cooling time of the weld heat-affected zone; obtaining the material properties of the high-strength steel under different welding thermal cycle conditions, establishing the relationship between the material properties and the peak temperature and cooling time of the welding thermal cycle using field variables, assigning the material properties to the corresponding weld heat-affected zone, and performing post-weld mechanical analysis to obtain the stress-strain curve of the high-strength steel weld joint. The method of the present invention can fully consider the impact of the welding thermal cycle on the material properties of the high-strength steel and more accurately obtain the failure mode of the high-strength steel.

Description

Technical Field

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

[0002] High-strength steel, with its combined advantages of high strength, low cost, low carbon, and environmental friendliness, holds enormous promise for application in steel structure engineering. However, when welded, high-strength steel, due to its high carbon equivalent and abundance of alloying elements, is extremely sensitive to welding heat input. This high heat input can severely reduce the strength of the material in the heat-affected zone (HAZ). Furthermore, the parent material near the HAZ of the welded joint can also experience strength degradation, or softening, due to the welding thermal cycle, causing the actual strength of the welded joint to be significantly lower than the designed value. Therefore, it is crucial to fully consider the impact of this material softening effect when designing welds.

[0003] Currently, the main methods for studying the strength of high-strength steel welds are experimental and finite element simulation. The experimental method primarily involves conducting standard tensile tests on the base material, welding material, and welded joints to obtain stress-strain curves, thereby studying the mechanical properties of high-strength steel welds. However, these experimental methods only capture overall mechanical properties and cannot accurately assess the true mechanical properties of the weld heat-affected zone (HAZ). Furthermore, improper welding techniques can introduce weld cracks, which can affect the accuracy of the measurement results.

[0004] It can be seen that the existing finite element simulation method mainly obtains the strength and mechanical properties of the weld through heat conduction analysis, thermal-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 effects brought about by the material softening effect. It 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, equipment and medium for numerical simulation of high-strength steel weld strength in order to solve the problems in the prior art.

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

[0007] A numerical simulation method for 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 using a heat source model to obtain temperature field data during the high-strength steel welding process;

[0009] The temperature field data was applied to the replicated finite element model of the high-strength steel welded joint. The sequential thermal-mechanical coupling method was used to analyze the residual stress of the high-strength steel welded joint, and the peak temperature and cooling time of the weld heat-affected zone corresponding to the residual stress of the high-strength steel welded joint were extracted.

[0010] 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 this 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 weld joint.

[0011] Preferably, the welding heat conduction analysis is performed on the finite element model of the high-strength steel welded joint through the 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.

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

[0013] 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:

[0014]

[0015] 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:

[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 from the center of the heat source in the welding direction, y is the distance from the center of the heat source in the weld width direction, and z is the distance from the center of the heat source in the weld depth direction; a1 and a2 are the geometric dimensions of the molten pool; b and c are the weld width and weld depth dimensions, respectively; f1 and f2 are the ellipsoidal heat source distribution parameters, satisfying f1+f2=2.

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

[0019] 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 based on the deviation of the comparative analysis results;

[0020] 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 the threshold, and the temperature field of the optimal simulated welding is obtained.

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

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

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

[0024] 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 using a heat source model to obtain temperature field data during the high-strength steel welding process;

[0025] An extraction module is used to apply temperature field data to the replicated finite element model of a high-strength steel weld joint, analyze the residual stress of the high-strength steel weld joint using a sequential thermal-mechanical coupling method, and extract the peak temperature and cooling time of the weld heat-affected zone corresponding to the residual stress of the high-strength steel weld joint;

[0026] The analysis module is used to obtain the material properties of high-strength steel under different welding thermal cycle conditions. By introducing field variables, the relationship between the material properties and the peak temperature and cooling time under the welding thermal cycle conditions is established. Based on this 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 weld joint.

[0027] The present invention provides a computer device, comprising 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 the above-mentioned method for numerical simulation of high-strength steel weld strength.

[0028] The present invention provides a storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the above-mentioned method for numerical simulation of high-strength steel weld strength.

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

[0030] During the welding process, the thermal cycle process undergone by the heat-affected zone material will change the material properties of high-strength steel. The method of the present invention uses a heat source model to perform welding heat conduction, obtains 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 welded joint, extracts the residual stress of the high-strength steel welded joint corresponding to the peak temperature and cooling temperature of the welding heat-affected zone, lays the foundation for the next step of mechanical analysis of the welded joint, and establishes the relationship between material properties and peak temperature and cooling temperature to obtain the changing connection between high-strength steel material properties and thermal cycle process, further improving the accuracy of the mechanical analysis results during the welding process, and finally assigns the material properties under the influence of welding thermal cycle to the corresponding welding heat-affected zone, performs post-weld mechanical analysis, and obtains the stress-strain curve and weld strength of the high-strength steel welded joint, thereby fully considering the influence of welding thermal cycle on the material properties of high-strength steel, and more accurately obtaining the stress-strain curve and failure mode of the high-strength steel welded joint. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0032] Figure 2 This is a comparison chart of temperature history data of high-strength steel welded joints of the present invention;

[0033] Figure 3 This is a comparison diagram of stress-strain curves of high-strength steel welded joints of the present invention;

[0034] Figure 4 This is a comparison diagram of the failure modes of the high-strength steel welded joints obtained by finite element analysis in the present invention. DETAILED DESCRIPTION

[0035] The following is a clear and complete description of the technical solutions of the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0036] Refer to the attached Figure 1 In this embodiment, a method for numerically simulating the strength of a high-strength steel weld includes the following steps:

[0037] Step S1: 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 using a heat source model to obtain temperature field data of the high-strength steel welding process.

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

[0039] A heat source model was used to analyze the heat conduction of a high-strength steel welded joint finite element model, obtaining temperature field data for the high-strength steel welding process. Specifically, two analysis steps, one for heating and the other for cooling, were set, both using the Heattransfer (Transient) analysis type. The temperature field data for the high-strength steel welding process was obtained through these two analysis steps. To ensure computational accuracy, the mesh in the weld and near-weld areas of the butt joint model was refined to 1mm. The mesh size in areas away from the weld could be increased to 2mm to reduce computational complexity, and the element type for the weld heat-affected zone was DC3D8.

[0040] The heat source model is a three-dimensional double ellipsoid heat source model. The specific details of the three-dimensional double ellipsoid heat source model are:

[0041] 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:

[0042]

[0043] 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:

[0044]

[0045] 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 weld width direction, and z is the distance from the center of the heat source in the weld depth direction; a1 and a2 are the geometric dimensions of the molten pool; b and c are the weld width and weld depth dimensions, respectively; f1 and f2 are the ellipsoidal heat source distribution parameters, satisfying f1+f2=2.

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

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

[0048] To ensure that the temperature field simulation during welding is consistent with the actual welding conditions, 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. The heat source model parameters are adjusted based on the deviation of the comparative analysis results.

[0049] 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 the threshold, and the temperature field of the optimal simulated welding is obtained. Figure 2 The temperature time history curve of the measuring point obtained for the welding test is consistent with the temperature time history curve at the same measuring point in the finite element model. It can be observed that the simulation results are consistent with the test results, indicating that the temperature field results obtained by simulation are accurate.

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

[0051] The peak temperature and cooling time of the HAZ unit refer to the highest temperature and time t experienced by the HAZ unit during the welding process. 8 / 5 , where time t 8 / 5 It indicates the time required for the unit temperature of the weld heat affected zone to drop from 800℃ to 500℃.

[0052] Using a sequential thermomechanical coupling method in ABAQUS, the temperature field data obtained from the heat conduction analysis was applied as a temperature load to a replicated finite element model of a high-strength steel weld joint. This sequential thermomechanical coupling analysis was used to determine the thermal strains of the weld heat-affected zone (HAZ) elements and, in turn, the corresponding weld residual stresses. The model used in the sequential thermomechanical coupling analysis was modified from the replicated heat conduction analysis model. In the weld residual stress analysis, the UEXPAN user subroutine was used to extract the peak temperature and cooling time during the heating and cooling cycles of the HAZ elements during the heat conduction analysis, laying the foundation for the subsequent mechanical analysis of the weld joint.

[0053] Step S3: Obtain the material properties of high-strength steel under different welding thermal cycle conditions. Based on the material properties, the USDFLD user subroutine is used 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, the material properties under the influence of the welding thermal cycle are assigned to the corresponding welding heat-affected zone unit, and post-weld mechanical analysis is performed to obtain the stress-strain curve and weld strength of the high-strength steel weld joint.

[0054] The UEXPAN user subroutine and the USDFLD user subroutine are used to assign the material properties affected by different welding thermal cycles to the corresponding weld heat affected zone elements 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 cycle conditions are the stress-strain curves obtained from the heat-affected specimen material properties (material performance) test, and the weld strength is obtained through the stress-strain curves.

[0056] In this embodiment, a thermal simulator is used to apply a specific welding thermal cycle (temperature rise and fall process) to the dog-bone tensile specimen, and the stress-strain curves of Q690 high-strength steel are obtained when the peak temperatures are 800°C, 1050°C, and 1320°C and the cooling time is 15s, 25s, and 50s, and the stress-strain curves are input into the material property module of the finite element model. Two field variables are introduced during the input, 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 welding heat affected zone unit in step 3, and the material properties under the influence of the welding thermal cycle are assigned to the corresponding welding heat affected zone unit in the analysis. Subsequently, the post-weld mechanical calculation analysis is 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 model calculation results were compared with the experimental results, and the model was applied to specimens with different welding parameters to verify the accuracy of the simulation method.

[0058] Figure 3 The stress-strain curve comparison diagram of high-strength steel welded joints is shown in Figure 2. Figure 4 This is a comparison diagram of the failure modes of high-strength steel welded joints analyzed by finite element analysis. Through analysis, it can be observed that the simulation results are well matched with the test results, which verifies the accuracy of this method.

[0059] Based on the above method, the present invention provides a high-strength steel weld strength numerical simulation system, 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 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 copied finite element model of the high-strength steel welded joint, and use the sequential thermal-mechanical coupling method to analyze the residual stress of the high-strength steel welded joint, 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, and establish the relationship between the material properties and the peak temperature and cooling time under the welding thermal cycle conditions through the introduction of 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 unit, and post-weld mechanical analysis is performed 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. The memory stores a program, and when the program is executed by the processor, the processor executes the steps of a high-strength steel weld strength numerical simulation method.

[0062] According to the disclosed embodiments, a computing device may communicate with one or more external devices (e.g., a keyboard, a pointing device, Bluetooth communications, etc.), or with any device that enables a computing device to communicate with one or more other computing devices (e.g., a router, a modem, etc.).

[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 method for numerically simulating the strength of a high-strength steel weld are implemented.

[0064] According to the disclosed embodiments, the storage medium may be a non-volatile computer-readable storage medium, such as, but 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 thereof. In the present invention, the storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, 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 to which the present invention belongs, several simple deductions or replacements can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A method for numerical simulation of high-strength steel weld strength, characterized in that: include: A finite element model of a high-strength steel welded joint was constructed, and welding heat conduction analysis was performed on the finite element model of the high-strength steel welded joint using a heat source model to obtain temperature field data during the high-strength steel welding process. Specifically, two analysis steps were set: heating up and cooling down. Temperature field data of the high-strength steel welding process was obtained through these two analysis steps. The temperature field data was applied to the replicated finite element model of the high-strength steel welded joint. The sequential thermal-mechanical coupling method was used to analyze the residual stress of the high-strength steel welded joint, and the peak temperature and cooling time of the weld heat-affected zone corresponding to the residual stress of the high-strength steel welded joint were extracted. Obtain the material properties of high-strength steel under different welding thermal cycle conditions. By introducing field variables, the relationship between the material properties and the peak temperature and cooling time under the welding thermal cycle conditions is established. Based on this relationship, the material properties under the influence of the welding thermal cycle are assigned to the corresponding welding heat-affected zone. Post-weld mechanical analysis is then performed to obtain the stress-strain curve and weld strength of the high-strength steel weld joint. 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 based on 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 the threshold, and the temperature field of the optimal simulated welding is obtained.

2. The method for numerical simulation of high-strength steel weld strength according to 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: Calculation formula of heat flux distribution function of the front half ellipsoid in the three-dimensional double ellipsoid heat source model for: ； Calculation formula of heat flux distribution function of the rear half ellipsoid in the three-dimensional double ellipsoid heat source model for: ； in: Q = ηUI , Q is the total welding power, η is the thermal efficiency coefficient, U is the welding voltage, 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, z is the distance from the center of the heat source in the direction of melting depth; a 1 and a 2 is the geometric size of the molten pool; b and c They are respectively the size of weld width and weld depth; f 1 and f 2 is the ellipsoidal heat source distribution parameter, satisfying f 1+ f 2=2.

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

4. The method for numerical simulation of high-strength steel weld strength according to claim 1, wherein: The material properties of the high-strength steel under different welding thermal cycle conditions are stress-strain curves obtained from heat-affected specimen material property tests.

5. A high-strength steel weld strength numerical simulation system, characterized in that: include: 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 using a heat source model to obtain temperature field data during the high-strength steel welding process. Specifically, two analysis steps are set: heating up and cooling down, and temperature field data of the high-strength steel welding process are obtained through these two analysis steps. The extraction module is used to apply temperature field data to the finite element model of the high-strength steel weld joint, analyze the residual stress of the high-strength steel weld 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 weld joint; An analysis module is used to obtain the material properties of high-strength steel under different welding thermal cycle conditions. The module then establishes 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 this relationship, the material properties under the influence of the welding thermal cycle are assigned to the corresponding welding heat-affected zone. Post-weld mechanical analysis is then performed to obtain the stress-strain curve and weld strength of the high-strength steel weld joint. 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 based on 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 the threshold, and the temperature field of the optimal simulated welding is obtained.

6. A computer device, characterized in that: The method 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 the method for numerical simulation of high-strength steel weld strength as claimed in any one of claims 1 to 4.

7. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for numerically simulating the strength of a high-strength steel weld are implemented as described in any one of claims 1 to 4.

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