Method for determining mechanical property parameters of bent pipe and related equipment

Abstract

The invention discloses a method for determining mechanical property parameters of a bent pipe and related equipment, and relates to the technical field of metal plastic working.The method comprises the steps that according to initial mechanical property parameters of a bent pipe plate, a first forming limit curve of the bent pipe plate is determined through an alternative theoretical model; determining a target theoretical model in the alternative theoretical models according to the first forming limit curve and the second forming limit curve; on the basis of the target theoretical model, a finite element simulation model for bent pipe forming is established, simulation is conducted, and a simulation result is obtained; optimizing the first forming limit curve according to the simulation result to obtain a third forming limit curve; and on the basis of the third forming limit curve and the target theoretical model, target mechanical property parameters of the bent pipe plate are obtained through reverse calculation. According to the method, experimental data and a theoretical model are combined, the forming limit curve is optimized, the pipe bending success rate is increased through simulation analysis, the optimal material mechanical property parameters are reversely calculated, the optimal matching of the material and the process can be achieved, and the cracking risk and the rejection rate are reduced.

Description

Technical Field

[0001] The present application relates to the technical field of metal plastic processing, and more specifically, to a method for determining the mechanical performance parameters of a bent pipe and related equipment. Background Art

[0002] With the continuous development of manufacturing technology, tube bending has been widely used in various fields such as automobiles, aerospace, rail transportation, and construction engineering. The mechanical properties of the sheet metal used in tube bending directly affect the forming quality and service life of the parts. However, due to the volatility of material properties and the complex forming stress state, accurately predicting the mechanical performance parameters of tube bending sheet metal has become particularly difficult. Therefore, research on accurate methods for determining the mechanical performance parameters of tube bending is of great significance for improving tube bending quality and optimizing material selection.

[0003] In related technologies, the mechanical performance parameters of bent tube sheet materials typically rely on theoretical model calculations or simple experimental testing. While theoretical models offer rapid calculation speed, their prediction accuracy is limited, making it difficult to fully reflect the material's true forming behavior under varying stress conditions. Relying solely on experimental testing is costly and difficult to fully cover a wide range of operating conditions, potentially leading to large errors in Forming Limit Curve (FLC) predictions. This can cause deviations in material selection and process design, impacting the forming quality and safety of bent tube parts. In other words, existing technologies for determining the mechanical performance parameters of bent tube sheet materials suffer from low prediction accuracy and an inability to balance theoretical calculations with experimental verification. Summary of the Invention

[0004] The Summary of the Invention section of this application introduces a series of simplified concepts that will be further described in detail in the Detailed Description of the Invention section. The Summary of the Invention section of this application is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0005] The method for determining the mechanical performance parameters of pipe bends and the related equipment provided in this application can combine experimental data with theoretical models to optimize the forming limit curve, improve the success rate of pipe bending through simulation analysis, and reversely calculate the optimal material mechanical performance parameters, thereby achieving the optimal match between materials and processes and reducing the risk of cracking and scrap rate.

[0006] In a first aspect, the present application provides a method for determining the mechanical performance parameters of a bent pipe, comprising: determining a first forming limit curve of the bent pipe plate through an alternative theoretical model based on the initial mechanical performance parameters of the bent pipe plate; determining a target theoretical model in the alternative theoretical model based on the first forming limit curve and a second forming limit curve, wherein the second forming limit curve is obtained by performing a forming limit test on the bent pipe plate; based on the target theoretical model, establishing a finite element simulation model of bent pipe forming and performing simulation to obtain simulation results; optimizing the first forming limit curve based on the simulation results to obtain a third forming limit curve; and based on the third forming limit curve and the target theoretical model, inversely calculating the target mechanical performance parameters of the bent pipe plate, wherein the target mechanical performance parameters include ultimate elongation and ultimate strain hardening exponent.

[0007] In some embodiments, optimizing the first forming limit curve according to the simulation results to obtain a third forming limit curve includes: vertically moving the first forming limit curve to coincide with the limit strain point in the simulation results to obtain a fourth forming limit curve; vertically moving the fourth forming limit curve downward by a preset safety margin to generate the third forming limit curve, wherein the third forming limit curve is a critical curve that satisfies the risk of cracking in bent tube forming, and the preset safety margin is determined based on the elongation fluctuation range and process fluctuation range of the bent tube plate.

[0008] In some embodiments, the elongation fluctuation range is greater than or equal to -5% and less than or equal to 5%; the process fluctuation range is greater than or equal to -3% and less than or equal to 3%.

[0009] In some embodiments, the method for determining the mechanical property parameters of a bent pipe further includes: determining a superposition value of the elongation fluctuation range and the process fluctuation range as the preset safety margin.

[0010] In some embodiments, determining the target theoretical model in the alternative theoretical models based on the first forming limit curve and the second forming limit curve includes: when the error between the first forming limit curve and the second forming limit curve is less than 5%, determining the alternative theoretical model corresponding to the first forming limit curve as the target theoretical model.

[0011] In some embodiments, determining the first forming limit curve of the bent tube sheet through an alternative theoretical model based on the initial mechanical property parameters of the bent tube sheet includes: inputting the yield strength, tensile strength, elongation, strain hardening exponent and plastic strain ratio of the bent tube sheet into the alternative theoretical model to obtain the first forming limit curve.

[0012] In some embodiments, the alternative theoretical models include the Keeler model, the Arcelor V9 model, and the Tata model.

[0013] In a second aspect, the present application also provides a device for determining the mechanical performance parameters of a bent pipe, including: a limit curve determination unit, used to determine a first forming limit curve of the bent pipe plate through an alternative theoretical model based on the mechanical performance parameters of the bent pipe plate; a theoretical model determination unit, used to determine a target theoretical model in the alternative theoretical model based on the first forming limit curve and the second forming limit curve, wherein the second forming limit curve is obtained by performing a forming limit test on the bent pipe plate; a model simulation unit, used to establish a finite element simulation model of bent pipe forming based on the target theoretical model and perform simulation to obtain simulation results; a curve optimization unit, used to optimize the first forming limit curve according to the simulation results to obtain a third forming limit curve; a performance determination unit, used to reversely calculate the target mechanical performance parameters of the bent pipe plate based on the third forming limit curve and the target theoretical model, wherein the mechanical performance parameters include elongation and strain hardening exponent.

[0014] In a third aspect, the present application further provides an electronic device comprising: a memory and a processor, wherein the processor is configured to implement the steps of the method for determining the mechanical performance parameters of a bent pipe as described in the first aspect when executing a computer program stored in the memory.

[0015] In a fourth aspect, the present application further provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method for determining the mechanical performance parameters of a bent pipe described in the first aspect.

[0016] In a fifth aspect, the present application also provides a computer program product, including a computer program or computer executable instructions. When the computer program or computer executable instructions are executed by a processor, the method for determining the mechanical performance parameters of the bent pipe provided in the embodiment of the present application is implemented.

[0017] In summary, this application comprehensively considers experimental data and theoretical models, calculates the first forming limit curve through the initial mechanical properties parameters of the bent tube plate, combines multiple alternative theoretical models, obtains the second forming limit curve through experimental testing, compares the first forming limit curve with the experimental data, and selects the target theoretical model with the smallest error, thereby reducing the error that may be caused by relying solely on the theoretical model and improving the prediction accuracy; based on the selected target theoretical model, a finite element simulation model of bent tube forming is established, and a numerical simulation of the bending process is performed. According to the simulation results, the first forming limit curve is optimized to obtain a more accurate third forming limit curve to ensure that it can reflect the actual deformation ability of the material in the actual bending process, thereby improving the success rate of the bending and reducing the scrap rate; through the optimized third forming limit curve, combined with the target theoretical model, the target mechanical properties parameters of the material are reversely calculated, which can provide a quantitative basis for material selection and manufacturing process. The material can be screened or adjusted according to the calculated target mechanical parameters to meet the bending requirements and avoid the material being too hard (easy to crack) or too soft (unable to maintain shape). In summary, the method for determining the mechanical performance parameters of pipe bends provided in this application combines experimental data with theoretical models, optimizes the forming limit curve, improves the success rate of pipe bending through simulation analysis, and reversely calculates the optimal material mechanical performance parameters, which can achieve the optimal match between materials and processes and reduce the risk of cracking and scrap rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present description. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0019] Figure 1 A schematic flow chart of a method for determining mechanical property parameters of a bent pipe provided in an embodiment of the present application;

[0020] Figure 2 A schematic diagram of a simulation result provided in an embodiment of the present application;

[0021] Figure 3 A comparative schematic diagram of determining a third forming limit curve provided in an embodiment of the present application;

[0022] Figure 4 A schematic diagram for comparing forming limit curves for determining a target theoretical model provided in an embodiment of the present application;

[0023] Figure 5 A schematic diagram of the structure of a device for determining the mechanical performance parameters of a bent pipe provided in an embodiment of the present application;

[0024] Figure 6A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] Terms in the specification, claims, and drawings of this application, such as "first," "second," "third," "fourth," and the like (if any), are used to distinguish between similar objects, rather than to describe a particular order or precedence. Therefore, it is understood that these terms can be used interchangeably where appropriate, so that the embodiments described can be implemented in a different order, unless otherwise specified in the drawings or descriptions. In addition, the terms "is" and "has" and any variations thereof in this application are intended to cover all possible constituent elements on a non-exclusive basis. For example, a process, method, system, product, or apparatus that includes several steps or units is not necessarily limited to the steps or units that are explicitly listed, but may also include other steps or units that are not explicitly listed, or steps or units that are inherent to the process, method, product, or apparatus.

[0026] In this application, a "module" or "unit" refers to a computer program or part of a computer program that has a specific function and works in conjunction with other related parts to achieve a predetermined goal. These modules or units can be implemented by software, hardware (such as processing circuits or memories), or a combination of the two. One or more processors or memories can implement one or more modules or units. At the same time, each module or unit can also be part of a larger module or unit.

[0027] The technical solutions in this application will be described in detail below in conjunction with the accompanying drawings in the embodiments. It should be noted that the embodiments described are only part of this application, not all embodiments. In the following description, the "some embodiments" mentioned are only a subset of all possible embodiments, which may be the same or different subsets, and different embodiments can be combined with each other without conflict.

[0028] Figure 1 This is a flow chart of a method for determining the mechanical performance parameters of a pipe bend provided in an embodiment of the present application. Figure 1 The method for determining the mechanical performance parameters of a pipe bend provided in an embodiment of the present application may include the following steps 101 to 105:

[0029] Step 101, determining a first forming limit curve of the bent tube sheet using an alternative theoretical model according to initial mechanical property parameters of the bent tube sheet;

[0030] In some examples, sheet metal used in tube bending processes, such as automotive exhaust pipes and aircraft piping, is a sheet metal material used in tube bending processes. For example, an automobile manufacturer uses 6061-T6 aluminum alloy sheet metal for exhaust pipe manufacturing, which requires tube bending to meet installation requirements. Initial mechanical properties describe the basic mechanical characteristics of the sheet metal used to bend tubes, characterizing properties such as strength and ductility. These parameters can be obtained through mechanical testing, such as tensile testing, or from the material supplier's technical data sheet. For example, the initial mechanical properties of a 6061-T6 aluminum alloy sheet include yield strength of 270 MPa, tensile strength of 310 MPa, elongation of 12%, strain hardening exponent of 0.15, and plastic strain ratio of 1.2. Alternative theoretical models are mathematical models used to calculate the forming limit curve of a material, typically based on different theories of metal plasticity. The first forming limit curve is a preliminary forming limit curve calculated by inputting the initial mechanical property parameters into the alternative theoretical model. It is used to predict the ultimate deformation capacity of the material.

[0031] By implementing step 101, the first forming limit curve is calculated using the existing mechanical property parameters through multiple alternative theoretical models. The first forming limit curve can be used to preliminarily evaluate the formability of the material and provide a reference for subsequent experiments and simulation analysis.

[0032] Step 102: determining a target theoretical model among the candidate theoretical models based on the first forming limit curve and the second forming limit curve, wherein the second forming limit curve is obtained by performing a forming limit test on a bent tube plate;

[0033] In some examples, the second forming limit curve is obtained through actual forming limit testing and can truly reflect the ultimate deformation capacity of the material. For example, the forming limit test of bent tubes and plates can be conducted using the ISO 12004-2 standard test method, recording the limit values ​​under different principal and secondary strains, and then plotting the second forming limit curve based on the test data. The target theoretical model is selected from multiple candidate theoretical models, the model whose first forming limit curve is closest to the second forming limit curve, to improve calculation accuracy.

[0034] For example, a Nakajima test is performed on 6061-T6 aluminum alloy sheet to obtain the second forming limit curve, and then the first forming limit curves of multiple alternative theoretical models are calculated, and error analysis is performed with the second forming limit curves. Finally, it is found that the error of the first forming limit curve calculated by the Arcelor V9 model is the smallest, and it can be determined as the target theoretical model to guide subsequent finite element simulation and parameter optimization.

[0035] By implementing step 102, the second forming limit curve is obtained by experimental testing, and compared with the first forming limit curve, and the target theoretical model with the smallest error is selected, which can more accurately reflect the real deformation capacity of the material and make the theoretical prediction closer to the actual situation.

[0036] Step 103: Based on the target theoretical model, a finite element simulation model of pipe bending is established and simulation is performed to obtain simulation results;

[0037] In some examples, the finite element simulation model of tube bending is a simulation environment constructed based on a target theoretical model using the finite element analysis method to simulate the deformation behavior of the tube bending plate during the actual forming process; for example, simulation software such as Abaqus and AutoForm is used to simulate a 90° tube bending of 6061-T6 aluminum alloy, input the material constitutive relationship and friction conditions, and apply a bending moment load. After 2000 steps of iterative calculation, the strain field distribution of the plate can be obtained; for example, Figure 2 The green area in the middle shows the area with the highest strain during the simulation. Simulation results are key output data obtained through finite element simulation, reflecting the deformation characteristics of the material during the bending process. These data can include principal strain, secondary strain, thinning rate, and springback angle. For example, in the 90° bending simulation, the principal strain in the critical area was 0.18, the secondary strain was -0.08, and the maximum thinning rate was 12%. There was no risk of cracking, indicating that the material was within the safe range of the first forming limit curve, making the process feasible.

[0038] By implementing step 103 and utilizing finite element simulation technology, key parameters such as the primary strain, secondary strain, and thinning rate during the pipe bending process can be analyzed in detail, thereby obtaining simulation results that can predict possible defects in the pipe bending and reduce later production risks.

[0039] Step 104, optimizing the first forming limit curve according to the simulation results to obtain a third forming limit curve;

[0040] In some examples, the first forming limit curve can be adjusted based on the limit strain point obtained by finite element simulation to make it more consistent with the actual forming capability of the material, thereby improving the prediction accuracy; the third forming limit curve is the final forming limit curve determined after simulation correction and consideration of safety margin adjustment, which can more accurately reflect the ultimate deformation capacity that the material can withstand during the actual pipe bending process.

[0041] By implementing step 104 and combining the simulation data, the first forming limit curve is optimized to make it more consistent with the actual strain state of the material, thereby improving the prediction capability of the bending limit.

[0042] Step 105: Based on the third forming limit curve and the target theoretical model, reverse calculation is performed to obtain target mechanical property parameters of the bent tube plate, wherein the target mechanical property parameters may include ultimate elongation and ultimate strain hardening exponent;

[0043] In some examples, the target mechanical performance parameters are key mechanical performance indicators that are ultimately determined through inverse calculations and can accurately reflect the deformation capacity of the bent tube sheet; based on the third forming limit curve and the target theoretical model, a mathematical inversion calculation formula can be constructed, and finite element simulation and experimental data can be used to substitute information such as the limit strain and strain path into the calculation to solve the target mechanical performance parameters. The ultimate elongation is the maximum strain that a material can withstand before failure (such as cracking), which indicates the limit of its ductility; the ultimate strain hardening exponent is a parameter that characterizes the strain hardening capacity of a material during plastic deformation, which affects the material's uniform deformation capacity and resistance to local necking. For example, the embodiment of the present application can reversely calculate that the elongation of the material is 28% and the strain hardening exponent is 0.178.

[0044] By implementing step 105 and utilizing reverse calculation, the optimal material mechanical parameters that meet the pipe bending requirements are obtained, providing quantitative standards for material selection and process optimization, thereby avoiding materials that are too hard or too soft and improving processing stability.

[0045] In summary, the embodiment of the present application comprehensively considers experimental data and theoretical models, calculates the first forming limit curve through the initial mechanical property parameters of the bent tube plate in combination with multiple alternative theoretical models, obtains the second forming limit curve through experimental testing, compares the first forming limit curve with the experimental data, and selects the target theoretical model with the smallest error, thereby reducing the error that may be caused by relying solely on the theoretical model and improving the prediction accuracy; based on the selected target theoretical model, a finite element simulation model of tube bending is established, and a numerical simulation of the tube bending process is performed. According to the simulation results, the first forming limit curve is optimized to obtain a more accurate third forming limit curve to ensure that it can reflect the actual deformation ability of the material in the actual tube bending process, thereby improving the success rate of tube bending and reducing the scrap rate; through the optimized third forming limit curve, combined with the target theoretical model, the target mechanical property parameters of the material are reversely calculated, which can provide a quantitative basis for material selection and manufacturing process. The material can be screened or adjusted according to the calculated target mechanical parameters to meet the tube bending requirements and avoid the material being too hard (easy to crack) or too soft (unable to maintain shape). In summary, the method for determining the mechanical performance parameters of pipe bends provided in the embodiment of the present application combines experimental data with theoretical models, optimizes the forming limit curve, improves the success rate of pipe bending through simulation analysis, and reversely calculates the optimal material mechanical performance parameters, which can achieve the optimal match between materials and processes and reduce the risk of cracking and scrap rate.

[0046] In some embodiments, the aforementioned step 104 may include: vertically moving the first forming limit curve to coincide with the limit strain point in the simulation results to obtain a fourth forming limit curve; vertically moving the fourth forming limit curve downward by a preset safety margin to generate a third forming limit curve, wherein the third forming limit curve is a critical curve that satisfies the risk of cracking in the bent tube forming, and the preset safety margin is determined based on the elongation fluctuation range and process fluctuation range of the bent tube plate.

[0047] In some examples, the fourth forming limit curve is a new curve obtained by adjusting the first forming limit curve during the optimization process to coincide with the extreme strain point in the simulation results. This curve is closer to the actual forming capability of the material predicted by the simulation. For example, starting from the first forming limit curve, the extreme strain point in the simulation results is extracted, and the first forming limit curve is shifted in the strain direction (i.e., vertically) so that its extreme strain point coincides with the extreme strain point in the simulation results, thereby generating the fourth forming limit curve. A preset safety margin is used to ensure that cracking does not occur during the pipe bending process. The fourth forming limit curve is shifted downward by a safety margin to form the third forming limit curve, which is ultimately used to determine the risk of cracking. The third forming limit curve is a new curve obtained by shifting the fourth forming limit curve downward by the preset safety margin. It serves as the final safety limit to ensure that the material does not crack during pipe bending.

[0048] For example, Figure 3 As shown in the figure, "FLC predicted by TaTa model" corresponds to the first forming limit curve, "simulated strain point" corresponds to the limit strain point of the simulation result, "FLC without considering safety margin" corresponds to the fourth forming limit curve, and "FLC considering safety margin" corresponds to the third forming limit curve.

[0049] Through the implementation of the above embodiment, by adjusting the first forming limit curve to the simulation limit strain point and reserving a safety margin, it is ensured that the fourth forming limit curve can accurately predict the ultimate forming ability of the material; by moving a portion of the fourth forming limit curve vertically downward, the third forming limit curve becomes a critical curve with no cracking risk, thereby improving the success rate of pipe bending.

[0050] In some embodiments, the elongation fluctuation range is greater than or equal to -5% and less than or equal to 5%; and the process fluctuation range is greater than or equal to -3% and less than or equal to 3%.

[0051] For example, the range of -5% or greater and 5% or less represents the possible fluctuation range of elongation. That is, relative to the nominal elongation of the material, its actual value may vary between -5% and +5%. For example, assuming that the elongation of a material is 20%, its actual measurement may fluctuate between 19% and 21% (i.e., -5% to 5%). The calculation formula is: Fluctuation range = 20% × [-5%, +5%] = [19%, 21%]. The range of -3% or greater and 3% or less represents the additional variation that may occur during the manufacturing process. That is, due to factors such as machining accuracy and equipment errors, the final forming performance may vary between -3% and +3%. For example, if the target elongation of a process design is 20%, but due to equipment errors, the actual elongation may fluctuate between 19.4% and 20.6% (i.e., -3% to 3%), the calculation formula is: Fluctuation range = 20% × [-3%, +3%] = [19.4%, 20.6%].

[0052] By implementing the above embodiment, it is ensured that the adjusted third forming limit curve can cover all possible changes in actual production, and it is also ensured that the calculated third forming limit curve is neither too conservative nor too radical, thereby improving process adaptability.

[0053] In some embodiments, the aforementioned method for determining the mechanical property parameters of a bent pipe may further include: determining the superposition value of the elongation fluctuation range and the process fluctuation range as a preset safety margin.

[0054] In some examples, the preset safety margin is a mathematical superposition of the material's elongation fluctuation range and the process fluctuation range to obtain a comprehensive safety margin, which is used to correct the forming limit curve to ensure that cracking or failure will not occur due to uncontrollable factors during the bending process; for example, if the elongation fluctuation range of a certain material is ±5% and the process fluctuation range is ±3%, then the preset safety margin = 5% + 3% = 8%.

[0055] Through the implementation of the above embodiment, the superposition value of material elongation fluctuation and process fluctuation is directly used as the safety margin, so that the forming limit curve optimization process has a theoretical basis, avoids subjective experience adjustment, and ensures that the optimized third forming limit curve is not affected by material or process errors in the actual production process, thereby improving the pass rate.

[0056] In some embodiments, the aforementioned step 102 may include: when the error between the first forming limit curve and the second forming limit curve is less than 5%, determining the alternative theoretical model corresponding to the first forming limit curve as the target theoretical model.

[0057] In some examples, the error between the first and second forming limit curves is the numerical deviation between the first and second forming limit curves. This error can be used to evaluate how well the theoretical model matches the material's true deformation capacity. For example, the difference between corresponding points on the two curves can be calculated, using mathematical methods such as mean relative error and root mean square error. The target theoretical model is the model that most closely matches the experimental data, i.e., the model with an error of less than 5%, selected from multiple candidate theoretical models. This model can be used for subsequent simulations and calculations. For example, the error between the first and second forming limit curves corresponding to all candidate models is calculated, and the model with the smallest error is selected.

[0058] For example, Figure 4 The relationship between different first forming limit curves and second forming limit curves is shown, where the curve shown by "Test" is the second forming limit curve, the curve shown by "TaTa" is the first forming limit curve corresponding to the Tata model, the curve shown by "Keeler" is the first forming limit curve corresponding to the Keeler model, and the curve shown by "Arcelor V9" is the first forming limit curve corresponding to the Arcelor V9 model.

[0059] Through the implementation of the above embodiment, an error threshold is set as a judgment criterion, and the theoretical model that best matches the experimental data is automatically selected, so that the selection of the target theoretical model is more accurate.

[0060] In some embodiments, the aforementioned step 101 may include: inputting the yield strength, tensile strength, elongation, strain hardening exponent, and plastic strain ratio of the bent tube plate into an alternative theoretical model to obtain a first forming limit curve.

[0061] In some examples, yield strength is the maximum stress a bent sheet can withstand before permanent plastic deformation occurs, typically measured in MPa (megapascals). Tension is applied to the sheet on a tensile testing machine, and the stress-strain curve is recorded. The stress corresponding to the yield point is the yield strength. Tensile strength is the maximum stress a bent sheet can withstand before tensile fracture and is an important indicator of its strength. Tension is continued until fracture, and the maximum stress, representing the tensile strength, is recorded. Elongation is the relative elongation of the gauge length of a bent sheet after tensile fracture, typically expressed as a percentage (%). This reflects the sheet's plastic deformation capacity. The relative elongation can be calculated by measuring the change in gauge length before and after fracture. The strain hardening exponent describes the degree of hardening of the bent sheet during plastic deformation. A higher strain hardening exponent indicates that the bent sheet is more susceptible to strengthening during deformation. The plastic strain ratio describes the ratio of transverse to longitudinal deformation during tensile deformation and is a key parameter for measuring the anisotropy of the bent sheet.

[0062] By implementing the above embodiment, the basic mechanical parameters of the material are input, combined with the alternative theoretical model, and the first forming limit curve is calculated, which can improve the accuracy of the forming limit curve calculation.

[0063] In some embodiments, the aforementioned alternative theoretical models may include the Keeler model, the Arcelor V9 model, and the Tata model.

[0064] It should be noted that the Keeler Model is a forming limit curve prediction model based on experimental statistics, primarily used to describe the forming limit of sheet metal under uniaxial tension. The Arcelor V9 Model, developed by the steel company ArcelorMittal, is primarily used to predict the forming limits of complex materials such as high-strength steel. The Tata Model, developed by Tata Steel, is a forming limit curve prediction method based on a combination of numerical simulation and experimental analysis, and is applicable to forming limit analysis of a variety of metal materials.

[0065] By implementing the above embodiments, appropriate theoretical models are selected for different plate characteristics, thus avoiding the limitations of a single model and improving calculation accuracy.

[0066] Furthermore, as an implementation of the aforementioned method embodiment, the present application also provides a device for determining the mechanical performance parameters of a bent pipe, which is used to implement the aforementioned method embodiment. This device embodiment corresponds to the aforementioned method embodiment. For ease of reading, this device embodiment for determining the mechanical performance parameters of a bent pipe will no longer describe the details of the aforementioned method embodiment one by one, but it should be clear that the device in the embodiment of the present application can implement all the contents of the aforementioned method embodiment. Figure 5As shown, the device 20 for determining the mechanical property parameters of the bent pipe includes: a limit curve determining unit 201, a theoretical model determining unit 202, a model simulation unit 203, a curve optimization unit 204 and a performance determining unit 205, wherein the limit curve determining unit 201 is used to determine a first forming limit curve of the bent pipe plate through an alternative theoretical model based on the mechanical property parameters of the bent pipe plate; the theoretical model determining unit 202 is used to determine a target theoretical model in the alternative theoretical model based on the first forming limit curve and the second forming limit curve, wherein the second forming limit curve is obtained by performing a forming limit test on the bent pipe plate; the model simulation unit 203 is used to establish a finite element simulation model of the bent pipe forming based on the target theoretical model and perform simulation to obtain simulation results; the curve optimization unit 204 is used to optimize the first forming limit curve based on the simulation results to obtain a third forming limit curve; and the performance determining unit 205 is used to reversely calculate the target mechanical property parameters of the bent pipe plate based on the third forming limit curve and the target theoretical model, wherein the mechanical property parameters may include elongation and strain hardening exponent.

[0067] In some embodiments, the curve optimization unit 204 is further used to vertically move the first forming limit curve to coincide with the limit strain point in the simulation results to obtain a fourth forming limit curve; and vertically move the fourth forming limit curve downward by a preset safety margin to generate a third forming limit curve, wherein the third forming limit curve is a critical curve that satisfies the risk of cracking in the bent tube forming, and the preset safety margin is determined based on the elongation fluctuation range and process fluctuation range of the bent tube plate.

[0068] In some embodiments, the elongation fluctuation range is greater than or equal to -5% and less than or equal to 5%; and the process fluctuation range is greater than or equal to -3% and less than or equal to 3%.

[0069] In some embodiments, the device 20 for determining the mechanical property parameters of the bent pipe further includes a safety margin determination unit for determining the superposition value of the elongation fluctuation range and the process fluctuation range as a preset safety margin.

[0070] In some embodiments, the theoretical model determining unit 202 is further configured to determine the alternative theoretical model corresponding to the first forming limit curve as the target theoretical model when the error between the first forming limit curve and the second forming limit curve is less than 5%.

[0071] In some embodiments, the limit curve determining unit 201 is further configured to input the yield strength, tensile strength, elongation, strain hardening exponent, and plastic strain ratio of the bent tube plate into the alternative theoretical model to obtain a first forming limit curve.

[0072] In some embodiments, alternative theoretical models include the Keeler model, the Arcelor V9 model, and the Tata model.

[0073] The present application also provides a computer-readable storage medium storing computer-executable instructions or a computer program. When the computer-executable instructions or the computer program are executed by a processor, the processor will be caused to execute any step of the method for determining the mechanical property parameters of the bent pipe provided in the present application.

[0074] In some embodiments, the computer-readable storage medium may be a random access memory (RAM), a read-only memory (ROM), a flash memory, a magnetic surface memory, an optical disc, or a compact disc read-only memory (CD-ROM); or it may be various devices including one or any combination of the above memories.

[0075] In some embodiments, computer-executable instructions may be in the form of a program, software, software module, script, or code, written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

[0076] In some embodiments, computer-executable instructions may, but need not, correspond to a file in a file system, may be stored as part of a file that stores other programs or data, for example, in one or more scripts in a HyperText Markup Language (HTML) document, in a single file dedicated to the program in question, or in multiple coordinating files (for example, files storing one or more modules, subroutines, or code portions).

[0077] In some embodiments, computer-executable instructions may be deployed to be executed on one electronic device, or on multiple electronic devices located at one site, or on multiple electronic devices distributed across multiple sites and interconnected by a communication network.

[0078] like Figure 6 As shown, the present application also provides an electronic device 30, including a memory 310, a processor 320 and a computer program 311 stored in the memory 310 and executable on the processor. When the processor 320 executes the computer program 311, any step of the above-mentioned method for determining the mechanical performance parameters of the bent pipe is implemented.

[0079] The present application also provides a computer program product, comprising a computer program or computer-executable instructions stored in a computer-readable storage medium. A processor of an electronic device reads the computer program or computer-executable instructions from the computer-readable storage medium and executes the computer program or computer-executable instructions, causing the electronic device to perform any step of the method for determining the mechanical property parameters of a pipe bend described above.

[0080] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for determining the mechanical performance parameters of a bent pipe, characterized in that: include: Determining a first forming limit curve of the bent tube sheet by using an alternative theoretical model according to initial mechanical property parameters of the bent tube sheet; determining a target theoretical model in the candidate theoretical models according to the first forming limit curve and the second forming limit curve, wherein the second forming limit curve is obtained by performing a forming limit test on the bent tube plate; Based on the target theoretical model, a finite element simulation model of pipe bending is established and simulation is performed to obtain simulation results; optimizing the first forming limit curve according to the simulation results to obtain a third forming limit curve; Based on the third forming limit curve and the target theoretical model, target mechanical property parameters of the bent tube plate are obtained by reverse calculation, wherein the target mechanical property parameters include ultimate elongation and ultimate strain hardening exponent.

2. The method for determining the mechanical performance parameters of a bent pipe according to claim 1, characterized in that: Optimizing the first forming limit curve according to the simulation result to obtain a third forming limit curve includes: vertically moving the first forming limit curve to coincide with the limit strain point in the simulation result to obtain a fourth forming limit curve; The fourth forming limit curve is vertically moved downward by a preset safety margin to generate the third forming limit curve, wherein the third forming limit curve is a critical curve that satisfies the risk of cracking in the bent tube forming, and the preset safety margin is determined based on the elongation fluctuation range and process fluctuation range of the bent tube plate.

3. The method for determining the mechanical performance parameters of a bent pipe according to claim 2, characterized in that: The elongation fluctuation range is greater than or equal to -5% and less than or equal to 5%; the process fluctuation range is greater than or equal to -3% and less than or equal to 3%.

4. The method for determining the mechanical performance parameters of a bent pipe according to claim 3, characterized in that: The method for determining the mechanical performance parameters of the elbow further includes: The superposition value of the elongation fluctuation range and the process fluctuation range is determined as the preset safety margin.

5. The method for determining the mechanical performance parameters of a bent pipe according to claim 1, characterized in that: Determining a target theoretical model among the alternative theoretical models according to the first forming limit curve and the second forming limit curve includes: When the error between the first forming limit curve and the second forming limit curve is less than 5%, the alternative theoretical model corresponding to the first forming limit curve is determined as the target theoretical model.

6. The method for determining the mechanical performance parameters of a bent pipe according to claim 1, characterized in that: The method of determining the first forming limit curve of the bent tube sheet by using an alternative theoretical model based on the initial mechanical property parameters of the bent tube sheet comprises: The yield strength, tensile strength, elongation, strain hardening exponent and plastic strain ratio of the bent tube plate are input into the alternative theoretical model to obtain the first forming limit curve.

7. The method for determining the mechanical performance parameters of a pipe bend according to any one of claims 1 to 6, characterized in that: The alternative theoretical models include the Keeler model, the Arcelor V9 model and the Tata model.

8. A device for determining the mechanical performance parameters of a bent pipe, characterized in that: include: a limit curve determining unit, configured to determine a first forming limit curve of the bent tube sheet by using an alternative theoretical model according to mechanical property parameters of the bent tube sheet; a theoretical model determining unit, configured to determine a target theoretical model among the candidate theoretical models based on the first forming limit curve and the second forming limit curve, wherein the second forming limit curve is obtained by performing a forming limit test on the bent tube plate; A model simulation unit is used to establish a finite element simulation model of pipe bending based on the target theoretical model and perform simulation to obtain simulation results; a curve optimization unit, configured to optimize the first forming limit curve according to the simulation result to obtain a third forming limit curve; A performance determination unit is used to reversely calculate the target mechanical performance parameters of the bent tube plate based on the third forming limit curve and the target theoretical model, wherein the mechanical performance parameters include elongation and strain hardening exponent.

9. An electronic device comprising: A memory and a processor, characterized in that the processor is used to implement the steps of the method for determining the mechanical performance parameters of a bent pipe as described in any one of claims 1 to 7 when executing the computer program stored in the memory.

10. A computer-readable 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 determining the mechanical property parameters of a bent pipe according to any one of claims 1 to 7 are implemented.

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