Finite element based heavy forging manipulator jaw high temperature wear amount prediction method

Abstract

The present application belongs to the technical field of mechanical friction and wear prediction, and particularly relates to a heavy-load forging manipulator jaw high-temperature wear amount prediction method based on finite elements. The method comprises: establishing a jaw clamping finite element model; extracting jaw actual working condition contact pressure; establishing and preprocessing a friction pair finite element model; constructing a high-temperature friction and wear theoretical model; secondary development of a UMESHMOTION user subroutine; numerical calculation and post-processing result extraction; establishing a contact pressure-load mapping relationship; and predicting actual working condition total wear amount and maximum wear depth. The present application reduces traditional physical tests through finite element numerical simulation, and constructs a thermal-mechanical coupling finite element model of a friction pair under high-temperature working conditions, synchronously introduces a temperature field and a stress field into a wear prediction framework, overcomes the limitations of traditional single mechanical or thermal analysis, realizes multi-physical field coupling simulation of heavy-load forging manipulator jaw high-temperature wear behavior, and further significantly improves prediction accuracy.

Description

Technical Field

[0001] This invention belongs to the field of mechanical friction and wear prediction technology, specifically relating to a method for predicting high-temperature wear of the jaws of heavy-duty forging manipulators based on the finite element method. Background Technology

[0002] With the development of industrial equipment towards high loads, high speeds, and high-temperature operating conditions, mechanical components are subjected to more complex thermo-mechanical coupling effects during frictional contact, making high-temperature friction and wear problems increasingly prominent. In metallurgy, mining, energy, and heavy equipment industries, key friction pairs operate under high-temperature conditions for extended periods, where material surfaces are prone to plastic deformation, oxidation spalling, and abrasive grain shedding, thereby accelerating wear and reducing the service life and operational stability of components. Therefore, accurately predicting the wear behavior and wear evolution patterns of materials under high-temperature conditions is of great significance for equipment life assessment, material selection, and structural optimization design.

[0003] Currently, the main methods for evaluating material wear performance include theoretical calculations, experimental testing, and statistical analysis. Traditional theoretical models are typically based on idealized assumptions and struggle to accurately describe the complex thermo-mechanical coupling wear behavior under high-temperature conditions. While experimental testing can obtain relatively realistic wear results, it suffers from long cycles, high costs, and difficulty in real-time characterization of the wear evolution process. Statistical analysis methods rely on large amounts of experimental data, resulting in relatively limited model generalization capabilities. Compared to these methods, finite element numerical simulation can comprehensively consider the influence of factors such as load, temperature, and sliding conditions on wear behavior, enabling dynamic simulation and quantitative prediction of the wear process.

[0004] However, for the specific object of heavy-duty forging manipulator jaws, they are simultaneously subjected to the thermal radiation of high-temperature forgings, frequent clamping contact pressure changes, and forging impact loads during service. Their friction and wear behavior is more complex than under conventional operating conditions, and existing general prediction methods are insufficient to accurately describe their wear evolution. Furthermore, current assessments of jaw wear still largely rely on empirical formulas or periodic shutdown measurements, lacking a wear prediction method that can effectively couple high temperature, heavy load, and impact effects, making it difficult to achieve early prediction of wear and lifespan.

[0005] Therefore, it is urgent to develop a method for predicting the jaw wear of heavy-duty forging manipulators that can effectively couple high temperature, heavy load and impact effects, so as to achieve accurate prediction of jaw wear under high temperature conditions and provide a theoretical basis for jaw replacement cycle setting and structural optimization. Summary of the Invention

[0006] To address the shortcomings of the existing technologies, this invention provides a finite element method for predicting high-temperature wear of heavy-duty forging manipulator jaws. This method solves the technical problems of low prediction accuracy, high testing costs, and lack of effective means for predicting wear of heavy-duty forging manipulator jaws under the combined effects of high temperature, heavy load, and impact loads in existing high-temperature wear prediction methods.

[0007] This invention constructs a thermo-mechanical coupled finite element model of friction pairs under high-temperature conditions, simultaneously introducing the temperature field and stress field into the wear prediction framework. This overcomes the limitations of traditional single mechanical or thermal analysis and realizes multi-physics coupled simulation of the high-temperature wear behavior of the jaws of heavy-duty forging manipulators. At the same time, it combines ALE adaptive meshing technology with the secondary development of the UMESHMOTION user subroutine to realize dynamic updating of the mesh in the wear area and continuous calculation of the wear process, effectively ensuring the stability and calculation accuracy of the numerical simulation.

[0008] This invention provides a method for predicting the high-temperature wear of the jaws of a heavy-duty forging manipulator based on the finite element method, comprising the following steps: S1. Establish a finite element model of the jaws: Perform a three-dimensional model of the jaws of the heavy-duty forging manipulator to obtain a three-dimensional model of the jaws of the heavy-duty forging manipulator, and import the jaws in the three-dimensional model of the jaws of the heavy-duty forging manipulator into ANSYS to establish a finite element model of the jaws. S2. Extraction of contact pressure under actual working conditions of the jaws: Set the jaw material, apply boundary conditions and loads to the finite element model of the jaw clamping based on the actual clamping conditions, extract the contact pressure distribution in the contact area between the jaws and the forging, and select the maximum contact pressure as the actual working condition contact pressure. S3. Establishment and preprocessing settings of the finite element model of the friction pair: Establish the finite element model of the friction pair based on the finite element software and complete the preprocessing settings for solving, so that the finite element model of the friction pair has the conditions for numerical solution of the high temperature wear process. S4. Construction of the theoretical model for high-temperature friction and wear: A theoretical model for the friction and wear of block samples under high-temperature conditions is constructed, and the expression is shown below: , In the formula, , For incremental step index, and ; For the wear node index, , For the first , In the increment step, the first The cumulative wear depth of each wear node. For the first In the increment step, the first The increase in wear depth generated by each wear node, where K is the comprehensive influence coefficient. , For the first , In the increment step, the first Contact pressure at each wear node, This represents the hardness value of the block sample at temperature T. , For the first , In the incremental step, at the contact point between the paired friction ball and the block sample... The tangential sliding velocity of each wear node is expressed in mm / s. , For the first , The time step of each increment step; S5. Secondary development of UMESHMOTION user subroutine: Embed the high-temperature friction and wear theoretical model constructed in step S4 into the UMESHMOTION user subroutine; S6. Numerical Calculation and Post-processing Result Extraction: The UMESHMOTION user subroutine with the high-temperature friction and wear theoretical model is embedded into the friction pair finite element model for numerical calculation. After the calculation is completed, the output calculation results are post-processed and extracted to obtain the contact pressure evolution, block sample temperature distribution, block sample wear amount in each incremental step, total block sample wear amount, and maximum wear depth of the block sample within the simulation prediction time. S7. Establish the contact pressure-load mapping relationship: Based on the simulation calculation results of the friction pair finite element model under different load conditions, extract the contact pressure corresponding to each load group, establish the fitting relationship curve between load and contact pressure, and obtain the contact pressure-load fitting curve. S8. Predict the total wear and maximum wear depth under actual working conditions: Substitute the actual working contact pressure of the heavy-duty forging manipulator jaws obtained in step S2 into the contact pressure-load fitting curve established in step S7 to obtain the equivalent load corresponding to the actual working contact pressure of the heavy-duty forging manipulator jaws. Substitute this equivalent load into the finite element model of the friction pair for numerical calculation to obtain the predicted values ​​of the total wear and maximum wear depth of the heavy-duty forging manipulator jaws within the simulation prediction time under actual working conditions.

[0009] Preferably, in step S2, the jaws are made of 16Mn or 35CrMo material. The specific steps of applying boundary conditions and loads to the jaw clamping finite element model based on the actual clamping conditions are as follows: apply fully constrained boundary conditions to the jaw shell, apply pressure load to the hydraulic cylinder to simulate clamping thrust, and at the same time apply an equivalent external load to the forging and set the friction coefficient between the jaws and the forging to zero.

[0010] Preferably, in step S3, an ABAQUS finite element model of the friction pair is established using ABAQUS finite element software. This model consists of a block-shaped specimen and paired friction balls positioned above the block-shaped specimen. The block-shaped specimen simulates the jaws of a heavy-duty forging manipulator, and the paired friction balls simulate the forgings held by the jaws. The specific steps for preprocessing the friction pair finite element model are as follows: S31. In the finite element model of the friction pair, the area in contact between the block sample and the paired friction balls is defined as the wear area. The wear area is set on the upper surface of the block sample, and the size and position of the wear area are determined according to the motion trajectory of the paired friction balls relative to the block sample. S32. Define the material of the paired friction ball, the material of the block specimen, and the material properties, wherein the material properties of the block specimen include elastic modulus, density, Poisson's ratio, thermal conductivity, and coefficient of linear expansion. S33. Set the finite element analysis step for the wear process and define the contact interaction between the block sample and the paired friction balls; S34. Use hexahedral elements for mesh generation, set the global mesh size according to the calculation accuracy requirements, and locally refine the predefined wear area; S35. Introducing ALE adaptive mesh technology, during the solution of the friction pair finite element model, based on the displacement of the wear area nodes and the degree of element distortion in each incremental step, the reconstruction and smoothing of the mesh node coordinates are automatically triggered. S36. Pre-configure the UMESHMOTION user subroutine and define the wear coefficient of the friction pair and the simulation prediction time.

[0011] Preferably, the paired friction spheres are hemispherical solid structures; in the finite element model of the friction pair, the paired friction spheres are defined as rigid bodies; The paired friction balls are made of Si3N4 material, and the block samples are made of 16Mn or 35CrMo material. The material properties of the block samples are selected and set according to the material handbook and the material performance change law under high temperature conditions.

[0012] Preferably, the finite element analysis steps include: In the initial stage, fully constrained boundary conditions are applied to the bottom surface of the block sample; During the heating phase, the surface temperature of the block sample is raised to a preset temperature by introducing a predefined temperature field. During the contact phase, a small load is applied to establish stable contact between the paired friction balls and the block sample; During the pressurization stage, load conditions are applied to the track center reference point and displacement boundary conditions are applied to the paired friction balls. The track center reference point is set on the central axis of the block specimen and is at the same horizontal height as the upper plane of the paired friction balls. During the rotational wear stage, a rotational speed boundary condition is applied to the reference point at the center of the track, driving the paired friction balls to move in a circular motion around the central axis of the block sample. This causes the nodes on the upper surface of the block sample to gradually displace along the normal direction, accumulating to form wear depressions.

[0013] Preferably, in the initial stage, the fully constrained boundary conditions are: all degrees of freedom of the bottom surface of the block specimen are constrained, that is, the translational degrees of freedom of the bottom surface of the block specimen in the X, Y, and Z axes and the rotational degrees of freedom about the X, Y, and Z axes are all constrained to zero; During the pressurization phase, the load conditions are as follows: the center of the upper plane of the paired friction ball is associated with the reference point of the track center through motion constraints, and the center of the upper plane of the paired friction ball is associated with the paired friction ball through rigid coupling constraints. The normal load is applied to the reference point of the track center, and is first transmitted to the center of the upper plane of the paired friction ball through motion constraints, and then transmitted to the paired friction ball through rigid coupling constraints. During the pressurization stage, the displacement boundary conditions are as follows: the paired friction balls retain only the translational degree of freedom in the Y-axis, and the translational degrees of freedom in other directions and all rotational degrees of freedom are constrained to zero; During the rotational wear stage, the rotational speed boundary condition is used to drive the paired friction balls to generate rotational motion, causing the paired friction balls to slide relative to the block sample. Specifically, the center of the upper plane of the paired friction balls is associated with the reference point of the track center through motion constraints, and an angular velocity is applied to the reference point of the track center to drive the paired friction balls to rotate around the central axis of the block sample. The contact interaction between the block specimen and the paired friction balls includes establishing a contact pair between the outer surface of the paired friction balls and the upper surface of the block specimen, and defining the normal contact behavior and the tangential friction coefficient; The block sample was discretized using C3D8R eight-node linear hexahedral elements during mesh generation. Each element contains 8 nodes, and each node has 3 translational degrees of freedom. The wear coefficient of the friction pair is determined based on the results of high-temperature friction and wear tests under different load conditions.

[0014] Preferably, the temperature range for high-temperature operating conditions is 400–500℃; the comprehensive influence coefficient consists of the micro-protrusion fracture probability coefficient, temperature correction coefficient, load correction coefficient, and material correction coefficient, and the expression is as follows: , In the formula, This represents the probability coefficient of fracture of the micro-protrusion. This is a temperature correction factor. This is the load correction factor. This is a material correction factor; In each incremental step, at the contact point between the paired friction balls and the block sample, the first... The tangential sliding velocity of each wear node is calculated using the following formula: , In the formula, The first contact point between the paired friction balls and the block sample Tangential sliding velocity at each wear node; The rotational angular velocity of the paired friction balls about the central axis of the block-shaped sample, in r / min; The first point of contact between the paired friction balls and the surface of the block sample. The horizontal distance from each wear node to the central axis of the block sample, i.e. the friction radius, is expressed in mm.

[0015] Preferably, the fracture probability coefficient of the micro-protrusion is determined by an experimental calibration method, specifically: a high-temperature friction and wear pre-test is conducted under reference working conditions, and the ratio of the wear amount obtained from the test to the wear amount obtained after solving the friction pair finite element model is taken as the value of the fracture probability coefficient of the micro-protrusion. The method for obtaining the temperature correction coefficient is as follows: under the premise that the load, materials and other test conditions remain unchanged, only the test temperature is changed, and the value of the coefficient is determined by the ratio of the wear amount under the pre-test conditions to the wear amount at the reference temperature under different temperature conditions. The method for obtaining the load correction factor is as follows: under the premise that the temperature, material and other test conditions remain unchanged, only the normal load is changed, and the value of the factor is determined by the ratio of the pre-test wear amount to the reference load wear amount under different load conditions. The method for obtaining the material correction coefficient is as follows: under the premise that the temperature, load and other test conditions remain unchanged, only the material of the block sample is changed, and the value of the coefficient is determined by the ratio of the wear amount of the pre-test to the wear amount of the reference material under the same working conditions for different materials.

[0016] Preferably, the initial time step size of each incremental step is equal, that is, the time step size before correction is equal in each incremental step. When using ALE adaptive mesh technology to reconstruct and smooth the mesh in each incremental step, to avoid numerical instability caused by excessive wear depth increment of a certain wear node in a certain incremental step, all wear nodes in the incremental step are traversed sequentially in each incremental step, and the wear depth increment of each wear node is calculated. If the wear depth increment of each wear node in the incremental step is less than or equal to the preset maximum allowable wear depth increment, then no time step correction is triggered, and all wear nodes in the incremental step are calculated according to the initial time step size without needing to be updated; if the wear depth increment of a certain wear node in the incremental step is greater than the preset maximum allowable wear depth increment, then time step correction is triggered. The time step correction process is as follows: Based on the current time step, a new time step is obtained. Wear nodes not yet calculated in this incremental step are recalculated using the new time step. If another correction is triggered, iterative correction continues based on the latest time step. After all wear nodes in this incremental step have been traversed, if one or more corrections have occurred, all wear nodes not calculated according to the final time step are uniformly updated using the final time step, and their wear depth increments are recalculated. Finally, based on the wear depth increments obtained by each wear node according to the final time step, the cumulative wear depth of each wear node in this incremental step is calculated. The time step correction formula is shown below: , In the formula, For the first The time step size after each incremental step correction This is the preset maximum allowable wear depth increment; Therefore, after the time step size is corrected for this increment, the corrected cumulative wear depth of all wear nodes within this increment is as follows: .

[0017] Preferably, after importing the UMESHMOTION user subroutine, which embeds a high-temperature friction and wear theoretical model, into the finite element model of the friction pair, in each increment step, the spatial coordinates and contact state parameters of each wear node in the wear area are first extracted; the sliding distance of each wear node in the current increment step is calculated based on the tangential sliding velocity of each wear node, and the wear depth increment of each wear node in the current increment step is calculated according to the high-temperature friction and wear theoretical model by combining the contact pressure, material hardness, and comprehensive influence coefficient of each wear node in the current increment step; then, by accumulating the wear depth increment of each wear node in each increment step, the cumulative wear depth of each wear node is obtained, and the position of each wear node is updated along the preset wear direction; at the same time, the mesh of the wear area is reconstructed and smoothed by combining ALE adaptive mesh technology to realize the dynamic update of the wear node position in the friction and wear process, and obtain the wear depth distribution of each wear node in the wear evolution process, wherein the contact state parameters include contact pressure, tangential contact stress, and contact slip; Considering the impact load in actual working conditions, before substituting the actual working contact pressure of the heavy-duty forging manipulator jaws obtained in step S2 into the contact pressure-load fitting curve established in step S7, the following steps are also included: using an impact correction coefficient to correct the actual working contact pressure of the heavy-duty forging manipulator jaws, the correction formula is as follows: , In the formula, This is the corrected actual working condition contact pressure. This represents the actual contact pressure under working conditions. This is the impact correction factor; Based on the predicted total wear and maximum wear depth of the jaws of a heavy-duty forging manipulator under actual working conditions within the simulation prediction period, the predicted total wear and maximum wear depth of the jaws under actual working conditions within the period of interest are obtained using a time-scale conversion method. The specific steps are as follows: S81. The total wear of the heavy-duty forging manipulator jaws within the simulation prediction duration is converted into the total wear per hour based on the time multiplier. Then, based on the daily effective wear duration and monitoring period of the equipment, it is converted into the wear of the heavy-duty forging manipulator jaws within the monitoring period. The expression is as follows: , , In the formula, This represents the total wear and tear per unit hour. The simulation predicts the total wear over the specified time period; The simulation prediction duration is in minutes; To monitor the total wear and tear over the period; This refers to the effective daily wear and tear time of the equipment, expressed in hours per day. To focus on the number of days within the period, the unit is days; S82. The maximum wear depth of the heavy-duty forging manipulator jaws within the simulation prediction duration is converted to the maximum wear depth per hour based on the time multiplier. Then, based on the daily effective wear duration and monitoring period of the equipment, it is converted to the maximum wear depth of the heavy-duty forging manipulator jaws within the monitoring period. The expression is as follows: , , In the formula, This represents the maximum wear depth per unit hour. To simulate and predict the maximum wear depth over the specified time period, To focus on the maximum wear depth within the cycle.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention reduces the need for traditional physical experiments through finite element numerical simulation and constructs a thermo-mechanical coupled finite element model of the friction pair under high-temperature conditions. It simultaneously introduces the temperature and stress fields into the wear prediction framework, overcoming the limitations of traditional single mechanical or thermal analysis. This achieves multi-physics coupled simulation of the high-temperature wear behavior of the jaws of heavy-duty forging manipulators without requiring extensive physical experiments. Compared to traditional methods, this invention not only more accurately describes the impact of thermo-mechanical coupling on wear, significantly improving prediction accuracy, but also effectively reduces experimental costs and time.

[0019] 2. This invention combines ALE adaptive meshing technology with secondary development of UMESHMOTION user subroutines. The former is responsible for the dynamic reconstruction of the mesh in the wear region to maintain computational stability, while the latter is responsible for the node-by-node calculation of wear depth and the update of wear node positions. The two work together to realize the continuous evolution simulation of wear morphology.

[0020] 3. This invention introduces a multi-factor correction system, including micro-protrusion fracture probability coefficient, temperature correction coefficient, load correction coefficient, and material correction coefficient, into the high-temperature friction and wear theoretical model. This enables the model to accurately reflect the influence of high temperature, load, and material property changes on wear behavior, thereby significantly improving the prediction accuracy of wear amount.

[0021] 4. By synchronously acquiring key physical field information such as contact pressure and temperature field evolution, this invention enriches the characterization dimensions of wear evolution and provides multi-dimensional data support for model verification and mechanism analysis.

[0022] 5. This invention establishes a contact pressure-load mapping relationship between the finite element model of the friction pair and the finite element model of the jaw clamp, maps the simulation results at the laboratory scale to actual engineering conditions, and obtains the predicted values ​​of the total wear and maximum wear depth of the jaw within the period of interest by combining the time-scale conversion method, thereby providing a quantitative theoretical basis for the determination of the jaw replacement cycle and the structural optimization design. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart of a method for predicting high-temperature wear of the jaws of a heavy-duty forging manipulator based on the finite element method, as described in an embodiment of the present invention. Figure 2 This is a schematic diagram of the three-dimensional model of the jaws of the heavy-duty forging manipulator in an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the boundary condition settings of the finite element model held by the jaws in an embodiment of the present invention, wherein... Figure 3 Point A represents pressure, point B represents long-range force, point C represents frictionless support, and point D represents fixed support. Figure 4 This is a cloud map showing the contact pressure distribution of the 35CrMo material jaws in the ANSYS finite element analysis of an embodiment of the present invention. Figure 5 This is a cloud map showing the contact pressure distribution of the 16Mn material jaws in ANSYS finite element analysis in an embodiment of the present invention. Figure 6 This is a schematic diagram of the structure of the finite element model of the friction pair in an embodiment of the present invention, wherein, Figure 6 101 is a pair of friction balls, 102 is a block sample, and 103 is the wear area; Figure 7 This is a schematic diagram of the grid setting of the block sample after introducing ALE adaptive grid technology in an embodiment of the present invention; Figure 8 This is a cross-sectional view of the wear region before the introduction of ALE adaptive mesh technology in this embodiment of the invention; Figure 9 This is a cross-sectional view of the wear region after introducing ALE adaptive mesh technology in an embodiment of the present invention; Figure 10 This is a wear morphology image of the upper surface of the block sample extracted after solving the finite element model of the friction pair in this embodiment of the invention; Figure 11 This is a cloud map of the contact pressure distribution of the block sample extracted after solving the finite element model of the friction pair in this embodiment of the invention. Figure 12 This is a contact pressure-load fitting curve of the 35CrMo material block sample in the embodiment of the present invention; Figure 13 This is a contact pressure-load fitting curve of the 16Mn material block sample in an embodiment of the present invention. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention in conjunction with the specific circumstances.

[0027] like Figure 1 As shown, this invention provides a method for predicting the high-temperature wear of the jaws of a heavy-duty forging manipulator based on the finite element method, comprising the following steps: S1. Establish a finite element model of the jaws: Perform a three-dimensional model of the jaws of the heavy-duty forging manipulator to obtain a three-dimensional model of the jaws of the heavy-duty forging manipulator, and import the jaws in the three-dimensional model of the jaws of the heavy-duty forging manipulator into ANSYS to establish a finite element model of the jaws.

[0028] In this embodiment, SolidWorks is used to perform 3D modeling of the jaws of the heavy-duty forging manipulator, resulting in a 3D model of the jaws. The jaws have a crab-shaped structure, as shown below. Figure 2As shown.

[0029] S2. Extraction of contact pressure under actual working conditions of the jaws: Set the jaw material, apply boundary conditions and loads to the finite element model of the jaws based on the actual clamping conditions, extract the contact pressure distribution in the contact area between the jaws and the forging, and select the maximum contact pressure as the actual working condition contact pressure.

[0030] In this application, the step S2 of applying boundary conditions and loads to the finite element model of the jaw clamping based on the actual clamping conditions specifically involves: applying fully constrained boundary conditions to the jaw shell, applying pressure loads to the hydraulic cylinder to simulate clamping thrust, and simultaneously applying equivalent external loads to the forging and setting the friction coefficient between the jaw and the forging to zero.

[0031] In this embodiment of the application, "fully constrained boundary conditions" refers to constraining all degrees of freedom of the jaws in the finite element model of the jaws, that is, constraining the translational degrees of freedom of the jaws in the X, Y, and Z axes and the rotational degrees of freedom about the X, Y, and Z axes to zero, so as to simulate the installation state of the jaws being completely fixed in the actual equipment.

[0032] In this embodiment of the application, a schematic diagram of applying boundary conditions to the finite element model of the jaw clamp is shown below. Figure 3 As shown, Figure 3 The document illustrates the location and type of boundary conditions applied in the ANSYS finite element model. Figure 3 Point A represents pressure, simulating the clamping thrust of the hydraulic cylinder; point B represents a long-range force acting on the center of gravity of the forging, simulating the overturning force generated by the forging's own weight; point C represents a frictionless support, used to eliminate interference from tangential friction when extracting contact pressure; and point D represents a fixed support, used to provide the constraint basis required for solving the finite element model of the jaws. After completing the above boundary condition settings, submitting the solution will extract the contact pressure distribution in the contact area between the jaws and the forging.

[0033] In this embodiment, a pressure load of 20 MPa is applied to the hydraulic cylinder to simulate the clamping thrust.

[0034] In this embodiment, the jaws are made of 16Mn or 35CrMo material.

[0035] In this embodiment, the clamping jaws of the 35CrMo material are V-shaped, and the contact pressure distribution cloud diagram in the ANSYS finite element analysis is shown below. Figure 4 As shown. From Figure 4 As can be seen, the maximum contact pressure of the 35CrMo material jaws is 289.93MPa, therefore its actual working contact pressure is 289.93MPa.

[0036] It should be noted that, Figure 4It is generated directly by finite element software. Since its maximum contact pressure occurs inside the finite element model held by the jaws, it is difficult to identify directly from the outside. Figure 4 The “maximum” markings indicate the maximum value points automatically identified by the finite element software, used to quickly locate the position of the maximum contact pressure in the simulation results.

[0037] In this embodiment, the clamping jaws of the 16Mn material have a crab-shaped structure, and its contact pressure distribution cloud diagram in ANSYS finite element analysis is shown below. Figure 5 As shown. From Figure 5 As can be seen, the maximum contact pressure of the 16Mn material jaws is 356.69 MPa, therefore its actual working contact pressure is 356.69 MPa.

[0038] It should be noted that the contact pressure distribution in the contact area between the jaws and the forging is extracted in this application, and the maximum value is selected as the actual working contact pressure because the maximum value corresponds to the most unfavorable load condition that the jaws bear during operation. Using this extreme working condition as the wear prediction benchmark can ensure that the prediction results cover the most severe wear situation in actual service, and provide a safety margin for jaw life assessment.

[0039] S3. Establishment and preprocessing settings of the finite element model of the friction pair: Establish the finite element model of the friction pair based on the finite element software and complete the preprocessing settings for solving, so that the finite element model of the friction pair has the conditions for numerical solution of the high temperature wear process.

[0040] In this application, the ABAQUS finite element software was used to establish the finite element model of the friction pair.

[0041] It should be noted that the geometric model of the friction pair finite element model can be modeled in different ways depending on the complexity of the structure: for simple structures, the model can be completed directly in ABAQUS finite element software; for complex structures, the model can be created using 3D modeling software such as SolidWorks or UG and then imported.

[0042] like Figure 6 As shown, the finite element model of the friction pair in this application consists of a block specimen 102 and a pair of friction balls 101 disposed above the block specimen 102. The block specimen 102 is used to simulate the jaws of a heavy-duty forging manipulator, and the pair of friction balls 101 is used to simulate the forging held by the jaws. The pair of friction balls 101 contact the upper surface of the block specimen 102 and move in a circular motion around the central axis of the block specimen 102, forming an annular wear track on the upper surface of the block specimen 102. This annular wear track is the wear area 103.

[0043] In this embodiment, the paired friction balls 101 move counterclockwise around the central axis of the block sample 102, such as... Figure 6 As shown.

[0044] In this embodiment, the diameter of the paired friction balls is 6 mm, and the size of the block sample is 37 mm × 37 mm × 6 mm.

[0045] It should be noted that, in order to facilitate the comparison and verification of simulation results and experimental results, the dimensions of the block sample and the paired friction balls in the embodiments of this application are set with reference to the sample specifications of the high-temperature friction and wear testing machine.

[0046] In this embodiment, the paired friction balls are hemispherical solid structures; in the finite element model of the friction pair, the paired friction balls are defined as rigid bodies.

[0047] In this application, the specific steps for preprocessing the friction pair finite element model are as follows: S31. In the finite element model of the friction pair, the area in contact between the block sample and the paired friction balls is defined as the wear area. The wear area is set on the upper surface of the block sample, and the size and position of the wear area are determined according to the motion trajectory of the paired friction balls relative to the block sample.

[0048] In this embodiment, the paired friction balls rotate around the central axis of the block sample with a radius of 5 mm, forming an annular wear track on the upper surface of the block sample. This annular wear track is the wear area.

[0049] S32. Define the materials of the paired friction balls, the materials of the block specimens, and their material properties. The material properties of the block specimens include the elastic modulus, density, Poisson's ratio, thermal conductivity, and coefficient of linear expansion.

[0050] Preferably, the material properties of the block sample are selected and set based on the material handbook and the material performance change law under high temperature conditions.

[0051] In this embodiment, the material properties of the block sample are selected based on the reference values ​​in the material handbook, and are corrected according to the variation law of the above performance parameters with temperature under high temperature conditions, so as to ensure that the numerical simulation parameters conform to the physical characteristics of the actual working conditions and ensure the reliability of the simulation results.

[0052] In this embodiment, the paired friction balls are made of Si3N4 material, and the block sample is made of 16Mn or 35CrMo material. The material properties of 16Mn and 35CrMo are shown in Table 1.

[0053]

[0054] S33. Set the finite element analysis step for the wear process and define the contact interaction between the block sample and the paired friction balls.

[0055] In this application, the finite element analysis step includes: In the initial stage, fully constrained boundary conditions are applied to the bottom surface of the block sample; During the heating phase, the surface temperature of the block sample is raised to a preset temperature by introducing a predefined temperature field. During the contact phase, a small load is applied to establish stable contact between the paired friction balls and the block sample; During the pressurization stage, load conditions are applied to the track center reference point and displacement boundary conditions are applied to the paired friction balls. The track center reference point is set on the central axis of the block specimen and is at the same horizontal height as the upper plane of the paired friction balls. During the rotational wear stage, a rotational speed boundary condition is applied to the reference point at the center of the track, driving the paired friction balls to move in a circular motion around the central axis of the block sample. This causes the nodes on the upper surface of the block sample to gradually displace along the normal direction, accumulating to form wear depressions.

[0056] It should be noted that the initial stage is a preset state and does not participate in the finite element analysis process, but the initial conditions defined therein are inherited and applied in the finite element analysis process.

[0057] In this embodiment of the application, "establishing stable contact between the paired friction balls and the block sample by applying a small load" means applying a small load so that the paired friction balls just make contact with the upper surface of the block sample to establish a stable initial contact state, providing contact conditions for the subsequent application of normal load. The load need not be limited to a specific value; it is sufficient to just establish a ball-disc contact state.

[0058] Preferably, in the initial stage, the fully constrained boundary conditions are: all degrees of freedom of the bottom surface of the block specimen are constrained, that is, the translational degrees of freedom of the bottom surface of the block specimen in the X, Y, and Z axes and the rotational degrees of freedom about the X, Y, and Z axes are all constrained to zero.

[0059] In this application, during the pressurization stage, the load conditions are as follows: the center of the upper plane of the paired friction ball is associated with the reference point of the track center through motion constraints, and the center of the upper plane of the paired friction ball is associated with the paired friction ball through rigid coupling constraints. The normal load is applied to the reference point of the track center, first transmitted to the center of the upper plane of the paired friction ball through motion constraints, and then transmitted to the paired friction ball through rigid coupling constraints.

[0060] In this embodiment, the normal load is the load applied along the central axis of the block specimen; the applied normal load is 10 to 50 N.

[0061] In this application, during the pressurization stage, the displacement boundary conditions are as follows: the paired friction balls retain only the translational degree of freedom in the Y-axis, while the translational degrees of freedom in other directions and all rotational degrees of freedom are constrained to zero.

[0062] In this embodiment, the central axis of the block sample coincides with the Y-axis.

[0063] In this application, during the rotational wear stage, the rotational speed boundary condition is used to drive the paired friction balls to generate rotational motion, causing the paired friction balls to slide relative to the block sample. Specifically, the center of the upper plane of the paired friction balls is associated with the reference point of the track center through motion constraints, and an angular velocity is applied to the reference point of the track center to drive the paired friction balls to rotate around the central axis of the block sample.

[0064] It should be noted that when applying angular velocity to the reference point at the center of the track in the ABAQUS finite element software, the specific steps are as follows: convert the angular velocity into rotational radians according to the analysis step duration, and assign the rotational radians to the rotational degree of freedom of the paired friction balls about the Y-axis.

[0065] In this embodiment of the application, the applied angular velocity is 200 r / min, which is converted to a rotational radius of 104.72 rad.

[0066] Preferably, the contact interaction between the block sample and the paired friction balls includes establishing a contact pair between the outer surface of the paired friction balls and the upper surface of the block sample, and defining the normal contact behavior and the tangential friction coefficient.

[0067] In this embodiment, the tangential friction coefficient is 0.5.

[0068] S34. Use hexahedral elements for mesh generation, set the global mesh size according to the calculation accuracy requirements, and locally refine the predefined wear area.

[0069] Preferably, the block sample is discretized using C3D8R eight-node linear hexahedral elements during mesh generation. Each element contains 8 nodes, and each node has 3 translational degrees of freedom.

[0070] In this embodiment, the paired friction balls are also meshed, but since they are defined as rigid bodies, their mesh is only used for contact detection and visualization and does not participate in deformation calculation, so there is no need to use a fine mesh.

[0071] S35. Introducing ALE adaptive mesh technology, during the solution of the friction pair finite element model, the reconstruction and smoothing of mesh node coordinates are automatically triggered based on the displacement of the wear area nodes and the degree of element distortion in each incremental step.

[0072] It should be noted that the ALE adaptive meshing technique can adjust the local mesh shape in real time along with the dynamic evolution of the wear surface while keeping the original topology of the friction pair finite element model unchanged, and map the stress field and temperature field results of the previous increment step to the new mesh, so as to maintain the calculation accuracy and numerical stability.

[0073] S36. Pre-configure the UMESHMOTION user subroutine and define the wear coefficient of the friction pair and the simulation prediction time.

[0074] In this embodiment, the wear coefficient of the friction pair is determined based on the results of high-temperature friction and wear tests under different load conditions.

[0075] It should be noted that the UMESHMOTION user subroutine is a user subroutine in ABAQUS / Standard used to define the movement of boundary nodes over time. It allows users to customize the movement of mesh nodes, thereby enabling mesh deformation, contact simulation, or tracking of arbitrary motion paths. In this application, the purpose of configuring the UMESHMOTION user subroutine is to: extract the spatial coordinates and contact state parameters of each wear node within the wear region in real time during wear simulation; calculate the sliding distance of each wear node in the current increment step based on its tangential sliding velocity; and obtain the wear depth increment of each wear node in the current increment step.

[0076] S4. Construction of the theoretical model for high-temperature friction and wear: A theoretical model for the friction and wear of block samples under high-temperature conditions is constructed, and the expression is shown below: , In the formula, , For incremental step index, and ; For the wear node index, , For the first , In the increment step, the first The cumulative wear depth of each wear node. For the first In the increment step, the first The increase in wear depth generated by each wear node, where K is the comprehensive influence coefficient. , For the first , In the increment step, the first Contact pressure at each wear node, This represents the hardness value of the block sample at temperature T. , For the first , In the incremental step, at the contact point between the paired friction ball and the block sample... The tangential sliding velocity of each wear node is expressed in mm / s. , For the first , The time step of each increment step.

[0077] In this application, the comprehensive influence coefficient is composed of the micro-protrusion fracture probability coefficient, temperature correction coefficient, load correction coefficient, and material correction coefficient, and the expression is as follows: , In the formula, This represents the probability coefficient of fracture of the micro-protrusion. This is a temperature correction factor. This is the load correction factor. This is the material correction factor.

[0078] In this embodiment, the comprehensive influence coefficient is obtained based on the results of high-temperature friction and wear pre-tests under load conditions of 10–50 N.

[0079] Preferably, the micro-protrusion fracture probability coefficient is used to characterize the influence of the contact state of micro-protrusions on the surface of the block sample, the actual contact area, and the micro-fracture behavior on the wear process. It is determined by experimental calibration method, specifically: a high-temperature friction and wear pre-test is carried out under the reference working condition, and the ratio of the wear amount obtained by the test to the wear amount obtained by solving the friction pair finite element model is taken as the value of the micro-protrusion fracture probability coefficient.

[0080] Preferably, the temperature correction coefficient is used to correct the influence of high-temperature softening and oxidation on wear behavior. The method for obtaining the coefficient is as follows: under the premise that the load, material and other test conditions remain unchanged, only the test temperature is changed, and the value of the coefficient is determined by the ratio of the wear amount under the pre-test conditions to the wear amount at the reference temperature under different temperature conditions.

[0081] For example, when predicting the wear amount at 420℃, the temperature correction factor is the ratio of the pre-test wear amount at 420℃ to the wear amount at the reference temperature; when predicting the wear amount at 480℃, the temperature correction factor is the ratio of the pre-test wear amount at 480℃ to the wear amount at the reference temperature.

[0082] Preferably, the load correction factor is used to correct the influence of load changes on wear behavior. The method for obtaining the factor is as follows: under the premise that the temperature, material and other test conditions remain unchanged, only the normal load is changed, and the value of the factor is determined by the ratio of the pre-test wear amount under different load conditions to the reference load wear amount.

[0083] For example, when predicting the wear amount under a 20N load, the load correction factor is the ratio of the pre-test wear amount under a 20N load to the wear amount under a reference load; when predicting the wear amount under a 50N load, the load correction factor is the ratio of the pre-test wear amount under a 50N load to the wear amount under a reference load.

[0084] Preferably, the material correction coefficient is used to correct the influence of material performance differences on wear behavior. The method for obtaining the coefficient is as follows: under the premise that the temperature, load and other test conditions remain unchanged, only the material of the block sample is changed, and the value of the coefficient is determined by the ratio of the wear amount of the pre-tested material to the wear amount of the reference material under the same working conditions.

[0085] In this embodiment, the micro-protrusion fracture probability coefficient and material correction coefficient are fixed values, while the temperature correction coefficient and load correction coefficient are determined according to the actual working conditions.

[0086] It should be noted that the preliminary test is a real physical test, and the reference working conditions, reference temperature, reference load, and reference material are set by the person skilled in the art according to the actual application needs.

[0087] Preferably, the hardness value of the block sample at temperature T is used to characterize the effect of high-temperature softening on the wear resistance of the material, and is obtained by fitting the material hardness test results or relevant literature data under different temperature conditions.

[0088] In this embodiment, the contact pressure in the high-temperature friction and wear theoretical model is automatically output by the ABAQUS finite element software after the contact solution is completed in each time increment step. The local pressure values ​​of each wear node in the contact area are obtained by extracting the contact pressure output variable. In addition, the contact pressure is dynamically updated with the solution process in each increment step and is used as the input parameter for calculating the wear depth increment of each wear node in the current increment step.

[0089] Preferably, in each incremental step, the contact point between the paired friction balls and the block sample is the first... The tangential sliding velocity of each wear node is calculated using the following formula: , In the formula, The first contact point between the paired friction balls and the block sample Tangential sliding velocity at each wear node; The rotational angular velocity of the paired friction balls about the central axis of the block-shaped sample, in r / min; The first point of contact between the paired friction balls and the surface of the block sample. The horizontal distance from each wear node to the central axis of the block sample, i.e. the friction radius, is expressed in mm.

[0090] In this application, the derivation process of the theoretical model for friction and wear of block samples under high-temperature conditions is as follows: S41. When the actual contact area and time increment between the paired friction balls and the block sample approach infinity, the differential forms of the wear volume and wear depth are as follows: , , , In the formula, For time derivative Internal wear volume; The normal load is the load applied along the central axis of the block specimen. The tangential sliding velocity is the velocity at the contact point between the paired friction balls and the block sample. For time derivative Increment of wear depth within, This represents the actual contact area between the paired friction balls and the block sample.

[0091] S42, Let the first The time step of each increment step is The wear depth increment generated by the nth wear node within this increment step is as follows: .

[0092] S43. Based on the wear depth increment generated by each wear node in each increment step, the cumulative wear depth of each wear node in each increment step is obtained by summing the wear depth increments of each wear node in each increment step, as shown in the following expression: .

[0093] Preferably, the initial time step size of each incremental step is equal, that is, the time step size before correction is equal in each incremental step. When using ALE adaptive mesh technology to reconstruct and smooth the mesh in each incremental step, to avoid numerical instability caused by excessive wear depth increment of a certain wear node in a certain incremental step, all wear nodes in the incremental step are traversed sequentially in each incremental step, and the wear depth increment of each wear node is calculated. If the wear depth increment of each wear node in the incremental step is less than or equal to the preset maximum allowable wear depth increment, then no time step correction is triggered, and all wear nodes in the incremental step are calculated according to the initial time step size without needing to be updated; if the wear depth increment of a certain wear node in the incremental step is greater than the preset maximum allowable wear depth increment, then time step correction is triggered. The time step correction process is as follows: Based on the current time step, a new time step is obtained. Wear nodes not yet calculated in this incremental step are recalculated using the new time step. If another correction is triggered, iterative correction continues based on the latest time step. After all wear nodes in this incremental step have been traversed, if one or more corrections have occurred, all wear nodes not calculated according to the final time step are uniformly updated using the final time step, and their wear depth increments are recalculated. Finally, based on the wear depth increments obtained by each wear node according to the final time step, the cumulative wear depth of each wear node in this incremental step is calculated. The time step correction formula is shown below: , In the formula, For the first The time step size after each incremental step correction This is the preset maximum allowable wear depth increment; Therefore, after the time step size is corrected for this increment, the corrected cumulative wear depth of all wear nodes within this increment is as follows: .

[0094] Suppose the initial time step of a certain increment step is... There are 6 wear nodes within this increment step, and the preset maximum allowable wear depth increment is [value missing]. Calculate the wear depth increment at each wear node sequentially: (1) Based on the initial time step The wear depth increment of wear node 1 was calculated. , The calculation results are temporarily saved; the calculation for wear node 1 is complete. (2) Based on the initial time step The wear depth increment of wear node 2 was calculated. , This triggers a time step correction, resulting in a new time step. The uncalculated wear nodes (i.e., wear nodes 3-6) will be calculated using the new time step. Perform calculations; (3) Based on the time step The wear depth increment of wear node 3 was calculated. , The calculation results are temporarily saved; the calculation for wear node 3 is complete. (4) Based on the time step The wear depth increment of wear node 4 was calculated. , Here, the time step correction is triggered again, resulting in a new time step. The uncalculated wear nodes (i.e., wear nodes 5-6) will be calculated using the new time step. Perform calculations; (5) Based on time step The wear depth increment of wear node 5 was calculated. , The calculation results are temporarily saved; the calculation for wear node 5 is complete. (6) Based on time step The wear depth increment of wear node 6 was calculated. , The calculation results are temporarily saved; the calculation of wear node 6 is complete. (7) Once all wear nodes in the increment have been traversed, the final time step in the increment step is used. All wear nodes (i.e., wear nodes 1 to 4) that were not calculated according to the final time step within the incremental step are uniformly updated, and their wear depth increments are recalculated. Finally, based on the wear depth increments obtained by each wear node according to the final time step, the cumulative wear depth of each wear node in the incremental step is calculated.

[0095] In this embodiment, the temperature range of the high-temperature operating condition is 400–500°C; when the time step correction condition is not triggered, the time step of each incremental step is equal.

[0096] S5. Secondary development of UMESHMOTION user subroutine: Embed the high-temperature friction and wear theoretical model constructed in step S4 into the UMESHMOTION user subroutine.

[0097] S6. Numerical Calculation and Post-processing Result Extraction: The UMESHMOTION user subroutine, which contains a high-temperature friction and wear theoretical model, is embedded into the finite element model of the friction pair for numerical calculation. After the calculation is completed, the output calculation results are post-processed and data is extracted to obtain the contact pressure evolution, temperature distribution of the block sample, wear amount of the block sample in each incremental step, total wear amount of the block sample, and maximum wear depth of the block sample within the simulation prediction time.

[0098] In this embodiment, the maximum wear depth of the block sample refers to the maximum value of the cumulative wear depth of each wear node in the wear area of ​​the block sample in the last incremental step, that is, the wear depth value corresponding to the deepest position of the wear mark, which is used to quantify the most severe degree of wear.

[0099] In this application, the UMESHMOTION user subroutine, which embeds a high-temperature friction and wear theoretical model, is imported into the finite element model of the friction pair. In each increment step, the spatial coordinates and contact state parameters of each wear node in the wear area are first extracted. Based on the tangential sliding velocity of each wear node, the sliding distance of the wear node in the current increment step is calculated. Combined with the contact pressure, material hardness, and comprehensive influence coefficient of each wear node in the current increment step, the wear depth increment of each wear node in the current increment step is calculated according to the high-temperature friction and wear theoretical model. Then, by accumulating the wear depth increments of each wear node in each increment step, the cumulative wear depth of each wear node is obtained, and the position of each wear node is updated along the preset wear direction. At the same time, the mesh of the wear area is reconstructed and smoothed by combining ALE adaptive mesh technology to realize the dynamic update of the wear node position in the friction and wear process and obtain the wear depth distribution of each wear node in the wear evolution process.

[0100] In this embodiment, the contact state parameters include contact pressure, tangential contact stress, and contact slip.

[0101] In this embodiment, the wear depth increment and cumulative wear depth of each wear node in each incremental step are calculated by the UMESHMOTION user subroutine, and the position of each wear node is updated along the preset wear direction. The wear depth distribution of each wear node is obtained based on the position change of each wear node before and after wear. Furthermore, based on the displacement of each wear node in the wear area, the wear volume of the block sample in each incremental step and the total wear volume of the block sample are obtained through post-processing, which are used as the wear amount of the block sample in each incremental step and the total wear amount of the block sample.

[0102] In this embodiment of the application, the calculation result output in step S6 is in the format of an ODB file.

[0103] In this embodiment of the application, a schematic diagram of the mesh setting for the block sample after introducing ALE adaptive meshing technology is shown below. Figure 7As shown, the cross-sectional view of the wear region before the introduction of ALE adaptive meshing technology is as follows: Figure 8 As shown, the cross-sectional view of the wear region after introducing ALE adaptive meshing technology is as follows. Figure 9 As shown. From Figure 8-9 It is evident that after updating with the ALE adaptive meshing technique, the wear nodes within the wear region move along the normal direction, and the mesh node positions and local mesh morphology dynamically adjust with the material removal process, while the mesh in the non-wear region remains basically stable. Simultaneously, the updated mesh maintains good continuity and integrity, without significant element distortion. Therefore, the synergistic application of the UMESHMOTION user subroutine and the ALE adaptive meshing technique can effectively simulate the dynamic evolution of the wear region, thereby significantly improving the stability and accuracy of high-temperature friction and wear numerical calculations.

[0104] In this embodiment of the application, after solving the finite element model of the friction pair, the surface wear morphology map and contact pressure distribution cloud map of the block sample were extracted, such as... Figure 10-11 As shown. By Figure 10 The wear morphology diagram of the upper surface of the block sample shown indicates that the wear region obtained by finite element simulation exhibits a ring-shaped distribution. The wear is mainly concentrated in the contact area of ​​the friction pair, and the boundary of the wear region has a high degree of consistency with the actual friction trajectory. This shows that the high-temperature friction and wear theoretical model established in this invention can effectively characterize the evolution law of wear morphology on the material surface during high-temperature friction. Figure 11 The pressure distribution cloud map of the block sample shows a clear pressure concentration phenomenon in the friction contact area. The maximum contact pressure is mainly distributed in the central region of the friction trajectory and gradually decreases along the contact edge, which is consistent with the distribution law of contact pressure spreading outward from the center during rotational friction. Therefore, the finite element-based method for predicting high-temperature wear of the jaws of heavy-duty forging manipulators established in this invention can effectively simulate the wear behavior and contact state evolution of materials under high-temperature conditions, and can reasonably characterize the distribution characteristics of contact pressure during friction, providing a reliable data foundation for subsequent wear prediction and engineering condition mapping.

[0105] S7. Establish the contact pressure-load mapping relationship: Based on the simulation calculation results of the friction pair finite element model under different load conditions, extract the contact pressure corresponding to each load group, establish the fitting relationship curve between load and contact pressure, and obtain the contact pressure-load fitting curve.

[0106] In this embodiment of the application, the contact pressure is used as the independent variable and the normal load is used as the dependent variable to obtain the contact pressure-load fitting curve.

[0107] In the embodiments of this application, the contact pressure-load fitting curves of the 35CrMo and 16Mn material block samples are shown in the figure below. Figure 12-13 As shown.

[0108] In this embodiment, the contact pressure-load fitting equation for the 35CrMo material block sample is as follows: .

[0109] In this embodiment, the contact pressure-load fitting equation for the 16Mn material block sample is as follows: .

[0110] S8. Predict the total wear and maximum wear depth under actual working conditions: Substitute the actual working contact pressure of the heavy-duty forging manipulator jaws obtained in step S2 into the contact pressure-load fitting curve established in step S7 to obtain the equivalent load corresponding to the actual working contact pressure of the heavy-duty forging manipulator jaws. Substitute this equivalent load into the finite element model of the friction pair for numerical calculation to obtain the predicted values ​​of the total wear and maximum wear depth of the heavy-duty forging manipulator jaws within the simulation prediction time under actual working conditions.

[0111] In this application, by obtaining the total wear amount and maximum wear depth prediction value of the jaws of the heavy-duty forging manipulator, its remaining service life can be further predicted, providing a basis for the formulation of replacement cycle.

[0112] Preferably, considering the existence of impact loads in actual working conditions, before substituting the actual working condition contact pressure of the heavy-duty forging manipulator jaws obtained in step S2 into the contact pressure-load fitting curve established in step S7, the method further includes: correcting the actual working condition contact pressure of the heavy-duty forging manipulator jaws using an impact correction coefficient, the correction formula being as follows: , In the formula, This is the corrected actual working condition contact pressure. This represents the actual contact pressure under working conditions. This is the impact correction factor.

[0113] In this embodiment, the impact correction coefficient is determined based on the characteristics of the impact load under the working condition, and its value ranges from 1.5 to 2.

[0114] Preferably, based on the predicted total wear and maximum wear depth of the heavy-duty forging manipulator jaws under actual working conditions within the simulation prediction time, a time-scale conversion method is used to obtain the predicted total wear and maximum wear depth of the heavy-duty forging manipulator jaws within the observation period under actual working conditions. The specific steps are as follows: S81. The total wear of the heavy-duty forging manipulator jaws within the simulation prediction duration is converted into the total wear per hour based on the time multiplier. Then, based on the daily effective wear duration and monitoring period of the equipment, it is converted into the wear of the heavy-duty forging manipulator jaws within the monitoring period. The expression is as follows: , , In the formula, This represents the total wear and tear per unit hour. The simulation predicts the total wear over the specified time period; The simulation prediction duration is in minutes; To monitor the total wear and tear over the period; This refers to the effective daily wear and tear time of the equipment, expressed in hours per day. To focus on the number of days within the period, the unit is days.

[0115] S82. The maximum wear depth of the heavy-duty forging manipulator jaws within the simulation prediction duration is converted to the maximum wear depth per hour based on the time multiplier. Then, based on the daily effective wear duration and monitoring period of the equipment, it is converted to the maximum wear depth of the heavy-duty forging manipulator jaws within the monitoring period. The expression is as follows: , , In the formula, This represents the maximum wear depth per unit hour. To simulate and predict the maximum wear depth over the specified time period, To focus on the maximum wear depth within the cycle.

[0116] In this application, the finite element method for predicting high-temperature wear of the jaws of a heavy-duty forging manipulator uses the analysis step duration (i.e., "simulation prediction duration") of the finite element calculation as the time reference during the numerical simulation stage to obtain the predicted values ​​of total wear and maximum wear depth at that time scale. Since finite element wear simulation is limited by computational cost and convergence, it is difficult to directly solve the entire timescale using the period of interest as the calculation window. Therefore, a time scale conversion method is used to obtain the predicted values ​​of total wear and maximum wear depth within the period of interest.

[0117] It should be noted that in practical engineering, the high-temperature wear of the jaws of heavy-duty forging manipulators is difficult to obtain in real time through online monitoring. On-site statistical data suffers from problems such as long acquisition cycles, high costs, and large dispersion. To address these practical measurement challenges, this invention proposes a finite element method for predicting the high-temperature wear of the jaws of heavy-duty forging manipulators. This method primarily simulates the wear behavior of high-temperature friction pairs under ideal working conditions (i.e., constant load, constant speed, and stable temperature field). Although it does not fully account for complex factors such as impact loads, temperature fluctuations, and intermittent operation during actual service, and the predicted results deviate somewhat from the actual wear on-site, it can quickly provide a reference for wear assessment at the engineering scale based on finite element simulation results. This provides a theoretical basis for determining jaw replacement cycles and optimizing structural design, demonstrating clear engineering practical value.

[0118] To verify the accuracy and reliability of this method, a block specimen wear test was conducted using an MS-HT1000 high-temperature friction and wear tester. The predicted results of total wear and maximum wear depth of block specimens made of different materials under different load conditions were compared with the experimental results. The predicted results of total wear and the experimental results are shown in Table 2, and the predicted results of maximum wear depth and the experimental results are shown in Table 3. In this experiment, the simulation prediction time was 20 minutes.

[0119] In this experiment, the relative error = .

[0120]

[0121] As shown in Table 2, under different load conditions, the predicted results of the total wear of block samples made of different materials are in good agreement with the experimental results, and the maximum relative error is controlled within 8%. This indicates that the high-temperature friction and wear theoretical model established in this invention and the high-temperature wear prediction method of the heavy-duty forging manipulator jaws based on finite element method have good reliability and stability.

[0122]

[0123] As shown in Table 3, under different load conditions, the predicted results of the maximum wear depth of block samples made of different materials are in good agreement with the experimental results, with the relative error controlled within 8%. This further verifies the applicability of the high-temperature friction and wear theoretical model and the finite element-based method for predicting the high-temperature wear of the jaws of a heavy-duty forging manipulator established in this invention in terms of wear depth prediction. Therefore, the high-temperature friction and wear theoretical model and the finite element-based method for predicting the high-temperature wear of the jaws of a heavy-duty forging manipulator established in this invention have high prediction accuracy under different materials and different load conditions.

[0124] Furthermore, to further verify the accuracy of the high-temperature friction and wear theoretical model established in this invention and the finite element-based method for predicting high-temperature wear of the jaws of heavy-duty forging manipulators in predicting wear depth, and to test the applicability of the prediction results under actual working conditions, this experiment is based on... Figure 4-5 The contact pressure distribution cloud map of the jaws of 35CrMo and 16Mn materials in ANSYS finite element analysis is shown. A complete conversion and verification was carried out from the actual working condition contact pressure to the equivalent load, and then to the maximum wear depth within the simulation prediction time, the maximum wear depth per unit hour, and the maximum wear depth per month. The specific process is as follows: First, by Figure 4-5 It can be seen that the actual working contact pressure of the 35CrMo material jaws is 289.93 MPa, which is corrected to 434.89 MPa after introducing an impact correction factor of 1.5; the actual working contact pressure of the 16Mn material jaws is 356.69 MPa, which is corrected to 535.03 MPa after introducing an impact correction factor of 1.5.

[0125] It should be noted that, in order to make the prediction results more accurate, the corrected actual working condition contact pressure data in this experiment were all retained to two decimal places and were not processed according to the rounding rules.

[0126] Secondly, such as Figure 12-13 As shown, based on the contact pressure-load mapping relationship established in the finite element model of the friction pair, it can be seen that when the actual working contact pressure of the 35CrMo material jaw is 434.89 MPa, its equivalent load is 38.28 N; when the actual working contact pressure of the 16Mn material jaw is 535.03 MPa, its equivalent load is 47.55 N.

[0127] Subsequently, the equivalent loads were re-substituted into the finite element model of the friction pair to obtain the maximum wear depth within the simulation prediction time. Then, using the time scale conversion method, combined with the equipment's effective daily wear time of 10 hours and the monthly working days of 30 days, the maximum wear depth per unit hour and the maximum monthly wear depth were calculated.

[0128] The results show that the maximum wear depth of the 35CrMo material jaws per hour is 17.598 μm, and its maximum monthly wear depth = 17.598 × 10 × 30 = 5279.4 μm ≈ 5.3 mm; the maximum wear depth of the 16Mn material jaws per hour is 13.812 μm, and its maximum monthly wear depth = 13.812 × 10 × 30 = 4143.6 μm ≈ 4.1 mm. Therefore, the maximum monthly wear depth of both materials falls within the range of 4–5.5 mm, which is basically consistent with the field statistics of a maximum monthly wear depth of approximately 5 mm. This further confirms the accuracy of the high-temperature friction and wear theoretical model established in this invention and the finite element-based method for predicting high-temperature wear of heavy-duty forging manipulator jaws in predicting wear depth, and that the prediction results can well reflect the wear patterns under actual working conditions.

[0129] In summary, this invention effectively reduces testing costs while ensuring prediction accuracy, and realizes the full-chain wear assessment from material friction pairs to engineering components, and from simulation prediction to engineering applications, thus possessing high engineering application value.

[0130] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for predicting high-temperature wear of the jaws of a heavy-duty forging manipulator based on the finite element method, characterized in that, Includes the following steps: S1. Establish a finite element model of the jaws: Perform a three-dimensional model of the jaws of the heavy-duty forging manipulator to obtain a three-dimensional model of the jaws of the heavy-duty forging manipulator, and import the jaws in the three-dimensional model of the jaws of the heavy-duty forging manipulator into ANSYS to establish a finite element model of the jaws. S2. Extraction of contact pressure under actual working conditions of the jaws: Set the jaw material, apply boundary conditions and loads to the finite element model of the jaw clamping based on the actual clamping conditions, extract the contact pressure distribution in the contact area between the jaws and the forging, and select the maximum contact pressure as the actual working condition contact pressure. S3. Establishment and preprocessing settings of the finite element model of the friction pair: Establish the finite element model of the friction pair based on the finite element software and complete the preprocessing settings for solving, so that the finite element model of the friction pair has the conditions for numerical solution of the high temperature wear process. S4. Construction of the theoretical model for high-temperature friction and wear: A theoretical model for the friction and wear of block samples under high-temperature conditions is constructed, and the expression is as follows: ， In the formula, , For incremental step index, and ; For the wear node index, , For the first , In the increment step, the first The cumulative wear depth of each wear node. For the first In the increment step, the first The increase in wear depth generated by each wear node, where K is the comprehensive influence coefficient. , For the first , In the increment step, the first Contact pressure at each wear node, This represents the hardness value of the block sample at temperature T. , For the first , In the first incremental step, at the contact point between the paired friction ball and the block sample... The tangential sliding velocity of each wear node is expressed in mm / s. , For the first , The time step of each increment step; S5. Secondary development of UMESHMOTION user subroutine: Embed the high-temperature friction and wear theoretical model constructed in step S4 into the UMESHMOTION user subroutine; S6. Numerical Calculation and Post-processing Result Extraction: The UMESHMOTION user subroutine with the high-temperature friction and wear theoretical model is embedded into the friction pair finite element model for numerical calculation. After the calculation is completed, the output calculation results are post-processed and extracted to obtain the contact pressure evolution, block sample temperature distribution, block sample wear amount in each incremental step, total block sample wear amount, and maximum wear depth of the block sample within the simulation prediction time. S7. Establish the contact pressure-load mapping relationship: Based on the simulation calculation results of the friction pair finite element model under different load conditions, extract the contact pressure corresponding to each load group, establish the fitting relationship curve between load and contact pressure, and obtain the contact pressure-load fitting curve. S8. Predict the total wear and maximum wear depth under actual working conditions: Substitute the actual working contact pressure of the heavy-duty forging manipulator jaws obtained in step S2 into the contact pressure-load fitting curve established in step S7 to obtain the equivalent load corresponding to the actual working contact pressure of the heavy-duty forging manipulator jaws. Substitute this equivalent load into the finite element model of the friction pair for numerical calculation to obtain the predicted values ​​of the total wear and maximum wear depth of the heavy-duty forging manipulator jaws within the simulation prediction time under actual working conditions.

2. The method for predicting high-temperature wear of the jaws of a heavy-duty forging manipulator based on finite element method according to claim 1, characterized in that, In step S2, the jaws are made of 16Mn or 35CrMo material. The specific steps for applying boundary conditions and loads to the jaw clamping finite element model based on the actual clamping conditions are as follows: apply fully constrained boundary conditions to the jaw shell, apply pressure load to the hydraulic cylinder to simulate clamping thrust, and at the same time apply an equivalent external load to the forging and set the friction coefficient between the jaws and the forging to zero.

3. The method for predicting high-temperature wear of the jaws of a heavy-duty forging manipulator based on finite element method according to claim 1, characterized in that, In step S3, the finite element model of the friction pair is established using ABAQUS finite element software. This model consists of a block-shaped specimen and paired friction balls positioned above the block-shaped specimen. The block-shaped specimen simulates the jaws of a heavy-duty forging manipulator, and the paired friction balls simulate the forgings held by the jaws. The specific steps for preprocessing the friction pair finite element model before solving are as follows: S31. In the finite element model of the friction pair, the area in contact between the block sample and the paired friction balls is defined as the wear area. The wear area is set on the upper surface of the block sample, and the size and position of the wear area are determined according to the motion trajectory of the paired friction balls relative to the block sample. S32. Define the material of the paired friction ball, the material of the block specimen, and the material properties, wherein the material properties of the block specimen include elastic modulus, density, Poisson's ratio, thermal conductivity, and coefficient of linear expansion. S33. Set the finite element analysis step for the wear process and define the contact interaction between the block sample and the paired friction balls; S34. Use hexahedral elements for mesh generation, set the global mesh size according to the calculation accuracy requirements, and locally refine the predefined wear area; S35. Introducing ALE adaptive mesh technology, during the solution of the friction pair finite element model, based on the displacement of the wear area nodes and the degree of element distortion in each incremental step, the reconstruction and smoothing of the mesh node coordinates are automatically triggered. S36. Pre-configure the UMESHMOTION user subroutine and define the wear coefficient of the friction pair and the simulation prediction time.

4. The method for predicting high-temperature wear of the jaws of a heavy-duty forging manipulator based on finite element method according to claim 3, characterized in that, The paired friction spheres are hemispherical solid structures; in the finite element model of the friction pair, the paired friction spheres are defined as rigid bodies. The paired friction balls are made of Si3N4 material, and the block samples are made of 16Mn or 35CrMo material. The material properties of the block samples are selected and set according to the material handbook and the material performance change law under high temperature conditions.

5. The method for predicting high-temperature wear of the jaws of a heavy-duty forging manipulator based on finite element method according to claim 3, characterized in that, The steps of finite element analysis include: In the initial stage, fully constrained boundary conditions are applied to the bottom surface of the block sample; During the heating phase, the surface temperature of the block sample is raised to a preset temperature by introducing a predefined temperature field. During the contact phase, a small load is applied to establish stable contact between the paired friction balls and the block sample; During the pressurization stage, load conditions are applied to the track center reference point and displacement boundary conditions are applied to the paired friction balls. The track center reference point is set on the central axis of the block specimen and is at the same horizontal height as the upper plane of the paired friction balls. During the rotational wear stage, a rotational speed boundary condition is applied to the reference point at the center of the track, driving the paired friction balls to move in a circular motion around the central axis of the block sample. This causes the nodes on the upper surface of the block sample to gradually displace along the normal direction, accumulating to form wear depressions.

6. The method for predicting high-temperature wear of the jaws of a heavy-duty forging manipulator based on finite element method according to claim 5, characterized in that, In the initial stage, the fully constrained boundary conditions are: all degrees of freedom of the bottom surface of the block specimen are constrained, that is, the translational degrees of freedom of the bottom surface of the block specimen in the X, Y, and Z axes and the rotational degrees of freedom about the X, Y, and Z axes are all constrained to zero; During the pressurization phase, the load conditions are as follows: the center of the upper plane of the paired friction ball is associated with the reference point of the track center through motion constraints, and the center of the upper plane of the paired friction ball is associated with the paired friction ball through rigid coupling constraints. The normal load is applied to the reference point of the track center, and is first transmitted to the center of the upper plane of the paired friction ball through motion constraints, and then transmitted to the paired friction ball through rigid coupling constraints. During the pressurization stage, the displacement boundary conditions are as follows: the paired friction balls retain only the translational degree of freedom in the Y-axis, and the translational degrees of freedom in other directions and all rotational degrees of freedom are constrained to zero; During the rotational wear stage, the rotational speed boundary condition is used to drive the paired friction balls to generate rotational motion, causing the paired friction balls to slide relative to the block sample. Specifically, the center of the upper plane of the paired friction balls is associated with the reference point of the track center through motion constraints, and an angular velocity is applied to the reference point of the track center to drive the paired friction balls to rotate around the central axis of the block sample. The contact interaction between the block specimen and the paired friction balls includes establishing a contact pair between the outer surface of the paired friction balls and the upper surface of the block specimen, and defining the normal contact behavior and the tangential friction coefficient; The block sample was discretized using C3D8R eight-node linear hexahedral elements during mesh generation. Each element contains 8 nodes, and each node has 3 translational degrees of freedom. The wear coefficient of the friction pair is determined based on the results of high-temperature friction and wear tests under different load conditions.

7. The method for predicting high-temperature wear of the jaws of a heavy-duty forging manipulator based on finite element method according to claim 1, characterized in that, The temperature range for high-temperature operating conditions is 400–500℃; the comprehensive influence coefficient consists of the micro-protrusion fracture probability coefficient, temperature correction coefficient, load correction coefficient, and material correction coefficient, as shown in the following expression: ， In the formula, This represents the probability coefficient of fracture of the micro-protrusion. This is a temperature correction factor. This is the load correction factor. This is a material correction factor; In each incremental step, at the contact point between the paired friction balls and the block sample, the first... The tangential sliding velocity of each wear node is calculated using the following formula: ， In the formula, The first contact point between the paired friction balls and the block sample Tangential sliding velocity at each wear node; The rotational angular velocity of the paired friction balls about the central axis of the block-shaped sample, in r / min; The first point of contact between the paired friction balls and the surface of the block sample. The horizontal distance from each wear node to the central axis of the block sample, i.e. the friction radius, is expressed in mm.

8. The method for predicting high-temperature wear of the jaws of a heavy-duty forging manipulator based on finite element method according to claim 7, characterized in that, The probability coefficient of micro-protrusion fracture was determined by experimental calibration method. Specifically, a high-temperature friction and wear pre-test was conducted under the reference working condition, and the ratio of the wear amount obtained by the test to the wear amount obtained by solving the finite element model of the friction pair was taken as the value of the probability coefficient of micro-protrusion fracture. The method for obtaining the temperature correction coefficient is as follows: under the premise that the load, materials and other test conditions remain unchanged, only the test temperature is changed, and the value of the coefficient is determined by the ratio of the wear amount under the pre-test conditions to the wear amount at the reference temperature under different temperature conditions. The method for obtaining the load correction factor is as follows: under the premise that the temperature, material and other test conditions remain unchanged, only the normal load is changed, and the value of the factor is determined by the ratio of the pre-test wear amount to the reference load wear amount under different load conditions. The method for obtaining the material correction coefficient is as follows: under the premise that the temperature, load and other test conditions remain unchanged, only the material of the block sample is changed, and the value of the coefficient is determined by the ratio of the wear amount of the pre-test to the wear amount of the reference material under the same working conditions for different materials.

9. The method for predicting high-temperature wear of the jaws of a heavy-duty forging manipulator based on finite element method according to claim 3, characterized in that, The initial time step size is equal for each incremental step, meaning the time step size before correction is equal for each incremental step. When using ALE adaptive meshing technology to reconstruct and smooth the mesh within each incremental step, to avoid numerical instability caused by excessive wear depth increment of a certain wear node in a certain incremental step, all wear nodes in that incremental step are traversed sequentially in each incremental step, and the wear depth increment of each wear node is calculated. If the wear depth increment of each wear node in that incremental step is less than or equal to the preset maximum allowable wear depth increment, then time step correction is not triggered, and all wear nodes in that incremental step are calculated according to the initial time step size without needing to be updated. If the wear depth increment of a certain wear node in that incremental step is greater than the preset maximum allowable wear depth increment, then time step correction is triggered. Specifically, correction is performed based on the current time step size to obtain a new time step size, and the wear depth increment of subsequent wear nodes that have not yet been calculated in that incremental step is recalculated with the new time step size. If a correction is triggered again, iterative correction will continue based on the latest time step. After all wear nodes within the increment step have been traversed, if one or more corrections have occurred, all wear nodes within the increment step that were not calculated according to the final time step will be uniformly updated using the final time step, and their wear depth increments will be recalculated. Finally, based on the wear depth increments obtained by each wear node according to the final time step, the cumulative wear depth of each wear node in the increment step will be calculated. The time step correction formula is as follows: ， In the formula, For the first The time step size after each incremental step correction This is the preset maximum allowable wear depth increment; Therefore, after the time step size is corrected for this increment, the corrected cumulative wear depth of all wear nodes within this increment is as follows: 。 10. The method for predicting high-temperature wear of the jaws of a heavy-duty forging manipulator based on finite element method according to claim 1, characterized in that, After importing the UMESHMOTION user subroutine, which embeds the high-temperature friction and wear theoretical model, into the finite element model of the friction pair, in each increment step, the spatial coordinates and contact state parameters of each wear node in the wear area are first extracted; based on the tangential sliding velocity of each wear node, the sliding distance of the wear node in the current increment step is calculated; and combined with the contact pressure, material hardness and comprehensive influence coefficient of each wear node in the current increment step, the wear depth increment of each wear node in the current increment step is calculated according to the high-temperature friction and wear theoretical model. Subsequently, by accumulating the wear depth increments of each wear node in each increment step, the cumulative wear depth of each wear node is obtained, and the position of each wear node is updated along the preset wear direction. At the same time, the mesh of the wear region is reconstructed and smoothed by combining ALE adaptive mesh technology to realize the dynamic update of the wear node position during the friction and wear process, and obtain the wear depth distribution of each wear node during the wear evolution process. Among them, the contact state parameters include contact pressure, tangential contact stress, and contact slip. Considering the impact load in actual working conditions, before substituting the actual working contact pressure of the heavy-duty forging manipulator jaws obtained in step S2 into the contact pressure-load fitting curve established in step S7, the following steps are also included: using an impact correction coefficient to correct the actual working contact pressure of the heavy-duty forging manipulator jaws, the correction formula is as follows: ， In the formula, This is the corrected actual working condition contact pressure. This represents the actual contact pressure under working conditions. This is the impact correction factor; Based on the predicted total wear and maximum wear depth of the jaws of a heavy-duty forging manipulator under actual working conditions within the simulation prediction period, the predicted total wear and maximum wear depth of the jaws under actual working conditions within the period of interest are obtained using a time-scale conversion method. The specific steps are as follows: S81. The total wear of the heavy-duty forging manipulator jaws within the simulation prediction duration is converted into the total wear per hour based on the time multiplier. Then, based on the daily effective wear duration and monitoring period of the equipment, it is converted into the wear of the heavy-duty forging manipulator jaws within the monitoring period. The expression is as follows: ， ， In the formula, This represents the total wear and tear per unit hour. The simulation predicts the total wear over the specified time period; The simulation prediction duration is in minutes; To monitor the total wear and tear over the period; This refers to the effective daily wear and tear time of the equipment, expressed in hours per day. To focus on the number of days within the period, the unit is days; S82. The maximum wear depth of the heavy-duty forging manipulator jaws within the simulation prediction duration is converted to the maximum wear depth per hour based on the time multiplier. Then, based on the daily effective wear duration and monitoring period of the equipment, it is converted to the maximum wear depth of the heavy-duty forging manipulator jaws within the monitoring period. The expression is as follows: ， ， In the formula, This represents the maximum wear depth per unit hour. To simulate and predict the maximum wear depth over the specified time period, To focus on the maximum wear depth within the cycle.

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