Numerical simulation method for tapered plane model of inertia friction welding

Abstract

The application discloses a kind of numerical simulation methods of inertia friction welding taper plane model, it is related to welding and cutting technical field.The method establishes the three-dimensional model of double joint in inertia friction welding process;Establish transient thermal coupling module, import fixed end and rotating end in the geometric structure of transient thermal coupling module, and give fixed end and rotating end as corresponding metal alloy material, respectively the fixed end and rotating end are dispersed into multiple grids;With the purpose of fixed end and rotating end sticking, adjust the grid position corresponding to fixed end and rotating end, and set the thermal boundary condition between fixed end and rotating end;By modifying the process parameters of fixed end and rotating end, and simulation is carried out, the temperature field, stress distribution and displacement nephogram of double joint are obtained.The method makes the accuracy of stress field, temperature field and displacement nephogram in inertia friction welding process obtained by numerical simulation of inertia friction welding process be higher.

Description

Technical Field

[0001] This invention relates to the field of welding and cutting technology, and in particular to a numerical simulation method for a tapered plane model of inertial friction welding. Background Technology

[0002] Offshore oil and gas extraction is a crucial part of energy security strategy. Approximately 45% of newly discovered oil and gas reserves are located offshore, and this proportion is increasing annually. Riser systems are one of the most critical technologies in deep-sea oil and gas extraction, and the most essential component of a riser system is the titanium alloy stress joint. Therefore, the welding of titanium alloy stress joints is a key focus.

[0003] Traditional welding methods for titanium alloys are prone to embrittlement and weld defects due to contamination from gases and other impurities. Therefore, inertial friction welding is commonly used in titanium alloy welding. Studying the stress field in inertial friction welding reveals the internal mechanical response of the material during welding, including the distribution, magnitude, and trend of stress. This is crucial for assessing the strength and toughness of the weld joint and helps prevent welding defects such as cracks and deformation, thereby improving the reliability of the weld joint. Studying the temperature field in inertial friction welding helps understand the heat transfer and distribution during welding, as well as the impact of temperature on material properties. Temperature is a key parameter in the welding process, directly affecting the melting, solidification, and phase transformation processes of the material, thus influencing the microstructure and properties of the weld joint. By simulating and analyzing the temperature field, welding parameters such as welding speed, friction pressure, and friction time can be optimized to achieve ideal weld quality. Displacement contour maps visually demonstrate the deformation of the material during welding. Displacement is the result of the material's response to thermal and mechanical stresses during welding. Analyzing the degree and distribution of deformation in the weld joint using displacement contour maps provides important information for optimizing the welding process.

[0004] However, the inertial friction welding process of tapered double joints is short, and due to the complexity of process changes, it is affected by multiple processes. In addition, the heat generation and upsetting pressure are very large. Furthermore, the double joints have a certain taper and different dimensions, and the stress field and temperature field of the workpiece are very complex. Therefore, the accuracy of existing technologies in numerically simulating the stress field, temperature field and displacement cloud map during the inertial friction welding process is low. Summary of the Invention

[0005] Therefore, it is necessary to provide a numerical simulation method for the tapered plane model of inertial friction welding to address the above-mentioned technical problems. This method enables the stress field, temperature field, and displacement cloud map obtained by numerical simulation of the inertial friction welding process to have high accuracy.

[0006] The present invention adopts the following technical solution:

[0007] This invention provides a numerical simulation method for a tapered plane model of inertial friction welding, comprising:

[0008] A three-dimensional model of the double joint during inertial friction welding is established; the three-dimensional model of the double joint includes a fixed end and a rotating end.

[0009] A transient thermo-coupling module is established. A fixed end and a rotating end are imported into the geometry of the transient thermo-coupling module, and the fixed end and the rotating end are assigned to corresponding metal alloy materials. The fixed end and the rotating end are discretized into multiple meshes respectively. The transient thermo-coupling module handles the transient process of thermo-coupling effect in inertial friction welding.

[0010] To achieve the goal of fitting the fixed end and the rotating end together, the corresponding mesh positions of the fixed end and the rotating end are adjusted, and the thermal boundary conditions between the fixed end and the rotating end are set.

[0011] By modifying the process parameters of the fixed end and the rotating end and performing simulation, the temperature field, stress field and displacement cloud map of the double joint were obtained; the process parameters include rotational speed, upsetting pressure and rotational inertia.

[0012] Preferably, the fixed end and the rotating end are discretized into multiple grids, including:

[0013] The fixed end and the rotating end are discretized into multiple grids along the length, width and height directions, and the grids are regular hexahedral elements.

[0014] Preferably, the plastic flow of metal during inertial friction welding is a nonlinear heat conduction process, and the thermal boundary conditions include heat conduction between the fixed end and the rotating end, as well as heat convection between the joint and the surrounding environment.

[0015] Preferably, the inertial friction welding process is divided into an initial friction stage, an unstable friction stage, a stable friction stage, and a top pressure maintenance stage.

[0016] Preferably, the method further includes:

[0017] In the initial friction stage of the inertial friction welding process, the Coulomb model is first used to describe the friction behavior. When the initial friction stress is greater than the shear yield strength of the material, the steady friction stage is entered, and the shear model is used to describe the friction behavior.

[0018] Preferably, the calculation formula for the Coulomb model is:

[0019]

[0020] Where, τ c The initial frictional stress is μ, the coefficient of friction is σ. n For normal stress, ν s The relative velocity of the weldment;

[0021] The calculation formula for the shear model is:

[0022]

[0023] Where, τ s For the friction stress during the stable friction stage, m is the shear friction factor, k is the shear yield strength of the material, and ν is the friction stress. s The relative velocity of the weldment.

[0024] Preferably, the inertial friction welding process is divided into an initial friction stage, an unstable friction stage, a stable friction stage, and a top pressure maintenance stage.

[0025] Preferably, the friction torque during inertial friction welding is calculated as follows:

[0026]

[0027] Where M is the frictional torque, r is the node radius, and τ f R is the frictional stress, π is the ratio of the circumference to the diameter, r1 is the node radius at the top of the rotating end, and r2 is the node radius at the contact end of the rotating end.

[0028] Preferably, the method further includes:

[0029] After setting the thermal boundary conditions between the fixed end and the rotating end, the simulation process is adjusted by setting the forming step size.

[0030] Preferably, both the fixed end and the rotating end are made of titanium alloy; the method further includes:

[0031] Before establishing the transient thermo-coupling module, select the database corresponding to the titanium alloy material in the physical property change curve calculation software;

[0032] Input the composition of titanium alloy materials into the database;

[0033] Set the environmental conditions and select the temperature range for calculation;

[0034] The physical property change curve calculation software was used to determine the change curve of the physical property parameters of the titanium alloy material.

[0035] The present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned numerical simulation method for a tapered plane model of inertial friction welding.

[0036] The present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the above-mentioned numerical simulation method for a tapered plane model of inertial friction welding.

[0037] The above-mentioned at least one technical solution adopted in this invention can achieve the following beneficial effects:

[0038] The three-dimensional model established in this invention for the inertial friction welding process uses three fixed and rotating ends of different sizes, compared to the traditional cylindrical model. Both the fixed and rotating ends have a 7° conical surface, which helps to expel excessively melted harmful substances and inclusions as flash. Combining the frictional characteristics and rotational form of inertial friction welding, the transient thermo-coupling module considers the influence of heat transfer processes such as heat conduction, convection, and radiation on the temperature field, performing transient thermo-coupling analysis to obtain the effects of rotational speed, upsetting pressure, and moment of inertia on the fixed and rotating ends. By modifying the process parameters of the fixed and rotating ends and performing simulation, the temperature field, stress field, and displacement cloud map of the double joint are obtained. The simulated stress field is used to prevent welding defects such as cracks and deformation, the simulated temperature field is used to optimize welding parameters such as welding speed, friction pressure, and friction time, and the simulated displacement cloud map is used to analyze the degree and distribution of deformation of the welded joint. This method makes the numerical simulation of the inertial friction welding process to obtain the stress field, temperature field, and displacement cloud map highly accurate. Attached Figure Description

[0039] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0040] Figure 1 A schematic flowchart of a numerical simulation method for a tapered plane model of inertial friction welding provided by the present invention;

[0041] Figure 2 This is a model diagram of the fixed end provided by the present invention;

[0042] Figure 3 This is a model diagram of the rotating end provided by the present invention;

[0043] Figure 4 The graph showing the change of Young's modulus with temperature, calculated by the JMatpro software provided for this invention;

[0044] Figure 5 A temperature field variation diagram over time during the tapered plane inertial friction welding process provided by the present invention;

[0045] Figure 6 A schematic diagram of the empirical equations provided for embodiments of the present invention;

[0046] Figure 7A schematic diagram of a numerical simulation device for a tapered plane model of inertial friction welding provided by the present invention;

[0047] Figure 8 A schematic diagram of a computer device for a numerical simulation method of a tapered plane model for inertial friction welding provided by the present invention. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0049] Devices such as desktop computers, servers, and laptops are capable of executing the solutions of this invention. For ease of explanation, the following description will focus on servers as the executing entity.

[0050] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0051] Figure 1 This is a schematic diagram of the numerical simulation method for a tapered plane model of inertial friction welding according to the present invention, which specifically includes the following steps:

[0052] S101: Establish a three-dimensional model of the double joint during inertial friction welding; the three-dimensional model of the double joint includes a fixed end and a rotating end.

[0053] Specifically, a three-dimensional model of the double-joint was created using the three-dimensional mechanical design software SolidWorks.

[0054] In an exemplary embodiment, both the fixed end and the rotating end are made of titanium alloy. The method further includes: before establishing the transient thermo-coupling module, selecting the database corresponding to the titanium alloy material in the property change curve calculation software; inputting the composition of the titanium alloy material into the database; setting the environmental conditions and selecting the temperature range for calculation; and using the property change curve calculation software to determine the property parameter change curve of the titanium alloy material.

[0055] Specifically, the density p, specific heat capacity cp, viscosity μ, surface tension σ, and thermal conductivity λ curves of TC4ELI titanium alloy as a function of temperature were calculated using the material property simulation software JMatPro. JMatPro software was then used to calculate the material properties of the molten metal at high temperatures, outputting the required density p, specific heat capacity cp, viscosity μ, surface tension σ, and thermal conductivity λ curves. The specific process is as follows: input the alloy composition; select the required database in JMatPro software and input the metal alloy composition; set the environmental conditions; select the calculation temperature range, and calculate the curves showing the change in material property parameters.

[0056] S102: Establish a transient thermo-coupling module, import a fixed end and a rotating end into the geometry of the transient thermo-coupling module, and assign the fixed end and the rotating end to the corresponding metal alloy material, and discretize the fixed end and the rotating end into multiple meshes respectively; the transient thermo-coupling module handles the transient process of thermo-coupling effect in the inertial friction welding process.

[0057] Specifically, a new numerical simulation task for inertial friction welding is created. Transient thermo-mechanical coupling modules for the inertial friction welding process are added to ABAQUS / standard and ABAQUS / exolict in the finite element analysis software ABAQUS to create a new simulation task. Since the inertial friction welding process involves transient processes with thermo-mechanical coupling, the explicit module exolict in the ABAQUS software is used. The exolict module performs thermo-mechanical coupling, thermocouple, and other analyses for complex nonlinear problems.

[0058] In an exemplary embodiment, the fixed end and the rotating end are discretized into multiple grids, including: the fixed end and the rotating end are discretized into multiple grids in the length, width and height directions, and the grids are regular hexahedral units.

[0059] Specifically, the three-dimensional models of the fixed end and the rotating end are discretized into regular hexahedral elements in three directions: length (X), width (Y), and height (Z). The model mesh at the joint is refined. The mesh at the welded joint is smaller than that in the non-joint area. Since the temperature field analysis exhibits nonlinear characteristics, the solid186 element in the cell function of Abaqus is selected.

[0060] S103: To achieve the goal of fitting the fixed end and the rotating end together, adjust the mesh positions corresponding to the fixed end and the rotating end, and set the thermal boundary conditions between the fixed end and the rotating end.

[0061] In one exemplary embodiment, the plastic flow of metal during inertial friction welding is a nonlinear heat conduction process, and the thermal boundary conditions include heat conduction between the stationary end and the rotating end, as well as heat convection between the joint and the surrounding environment.

[0062] Specifically, by adjusting the parallel distances of the x, y, and z axes of the fixed and rotating ends, and by performing a certain dimensional translation, the welding surfaces of the fixed and rotating ends are brought together so that they can directly rotate and rub against each other. The specific steps are as follows: Locate the position coordinates of the target fixed and rotating ends, select a fixed coordinate position, and then move the center points of the fixed and rotating ends parallel to each other along the x, y, and z axes to a fixed position, bringing the fixed and rotating ends into contact.

[0063] S104: By modifying the process parameters of the fixed end and the rotating end and performing simulation, the temperature field, stress field and displacement cloud map of the double joint are obtained; the process parameters include rotational speed, upsetting pressure and moment of inertia.

[0064] In an exemplary embodiment, the method further includes: first using a Coulomb model to describe the friction behavior in the initial friction stage of the inertial friction welding process; and then using a shear model to describe the friction behavior when the initial friction stress is greater than the shear yield strength of the material.

[0065] Specifically, the invention sets up heat conduction between the fixed end and the rotating end, sets the initial temperature, and sets the heat radiation generated by the welded joint to the environment. Its boundary conditions also include heat convection between the side of the joint and the surrounding environment during inertial friction welding, as well as the temperature-dependent friction conditions between the fixed end and the rotating end. Since inertial friction welding generates heat through friction, the weld will be affected by the forging speed and the top pressure during the re-friction welding process, ultimately reflecting the change in the elasticity of the material at the re-welding temperature. The invention uses the Coulomb model and the shear model to describe the friction behavior of the welding process, respectively.

[0066] Specifically, during the stage from contact to the start of friction between the two welded parts, the temperature rises slowly, and the friction coefficient between the contact surfaces of the fixed and rotating ends is relatively large. At this time, dry friction dominates, and the initial friction stage begins. This stage is calculated using the Coulomb friction model, and the calculation method of the Coulomb model is shown in formula (1):

[0067]

[0068] Where, τ c The initial frictional stress is μ, the coefficient of friction is σ. n For normal stress, ν s The relative velocity of the weldment.

[0069] Once the welding enters the stable friction stage, the temperature rises significantly, and the metal material at the welding interface undergoes plastic deformation, and the contact surface also gradually deforms. At this point, the Coulomb friction model no longer satisfies the actual welding situation, and the shear friction model is selected to continue calculating the friction stress. The calculation method of the shear model is shown in formula (2):

[0070]

[0071] Where, τ s For the friction stress during the stable friction stage, m is the shear friction factor, k is the shear yield strength of the material, and ν is the friction stress. s The relative velocity of the weldment.

[0072] During welding, as the temperature gradually increases, the yield strength of the material decreases. If the Coulomb model is used to calculate the frictional force, the calculated frictional force will be greater than the shear yield strength of the material, which does not match the actual frictional behavior. Therefore, it is necessary to switch to the shear model for calculation, and there must be a criterion to determine when to switch to the shear model. That is, when the initial frictional stress is greater than the shear yield strength of the material, the Coulomb model is converted to the shear model.

[0073] In one exemplary embodiment, the inertial friction welding process is divided into an initial friction stage, an unstable friction stage, a stable friction stage, and a top pressure maintenance stage.

[0074] Specifically, the welding process of inertial friction welding is due to the rotation of the rotating end and the application of upsetting pressure to the fixed end to make it move forward. Therefore, it is necessary to fix the boundary conditions. Abquse fixes the degrees of freedom of the fixed end and the rotating end by fixing the horizontal displacement of the top of the fixed end and fixing the horizontal rotation of the rotating end. In addition, since the model dimensions of the fixed end and the rotating end are not uniform, in order to prevent excessive displacement during the rotation process, it is necessary to limit the vertical displacement of the fixed end and the rotating end.

[0075] According to the theory of heat conduction, all heat generation phenomena in solids can be described by the general equation of heat transfer and the boundary conditions reflecting the interaction between the heat transfer body and the environment. For an axisymmetric temperature field, the heat transfer equation in polar coordinates can be derived as shown in equation (3):

[0076]

[0077] Where ρ is density, C is specific heat capacity, and λ is density. x , λ y , λ z Let be the thermal conductivity coefficients of the material along the x, y, and z directions, respectively, and Q be the intensity of the internal heat source. The temperature gradient is expressed in Kelvin (K), where t is time and T is temperature.

[0078] The heat source for friction welding is quite special. It mainly comes from heat generated by friction, which is converted from kinetic energy into internal energy to provide the heat source. The heat source at the contact surface (welding surface) is defined by formula (4), which is shown below:

[0079] dP / dS=2πμpn (4);

[0080] Where P is the frictional heat power, S is the cross-sectional area, p is the upsetting pressure, μ is the friction coefficient, n is the rotational speed, and π is the ratio of the circumference to the diameter of the circle.

[0081] Since the rotating end rotates and the fixed end is subjected to upsetting pressure to move it forward, it is necessary to fix its boundary conditions. abquse fixes the degrees of freedom of the fixed end and the rotating end by fixing the horizontal displacement of the top end of the fixed end and fixing the horizontal rotation of the rotating end. In addition, since the model dimensions of the fixed end and the rotating end are not uniform, in order to prevent excessive displacement during rotation, it is necessary to limit the vertical displacement of the fixed end and the rotating end.

[0082] In an exemplary embodiment, the frictional torque during the inertial friction welding process is calculated as shown in formula (5):

[0083]

[0084] Where M is the frictional torque, r is the node radius, and τ f R is the frictional stress, r1 is the node radius at the top of the rotating end, and r2 is the node radius at the contact end of the rotating end.

[0085] Specifically, during the welding process, the rotational speed of the joints at both ends gradually decreases due to friction until the welding is completed and the joints stop rotating. The frictional torque during friction welding is calculated using formula (5). The change in the rotational speed of the rotating end during the welding process is obtained through the frictional torque. The calculation method for the change in rotational speed within a very small time step is shown in formula (6):

[0086]

[0087] Where Δω is the change in rotational speed, I is the moment of inertia, M is the frictional torque, and Δt is the change in time.

[0088] In one exemplary embodiment, the method further includes adjusting the simulation process by setting a forming step size after setting the thermal boundary conditions between the fixed end and the rotating end.

[0089] Specifically, in the "Analysis Step" module of the ABAQUS software, the simulation process can be adjusted by setting different step sizes.

[0090] The evolution of the temperature field during inertial friction welding at key nodes is described in four stages: initial friction stage, unstable friction stage, stable friction stage, and upsetting pressure maintenance stage. The sensitivity of various parameters to the temperature field is analyzed and compared at selected key nodes. High-temperature points at the upper and lower joints of the formed part are marked, including the influence of rotational speed, upsetting pressure, and moment of inertia on the temperature field changes of the upper and lower joints. The changes in heating rate and heat flux density during the friction process are also calculated.

[0091] By solving the stress field, the effects of the axial stress field, equivalent stress field, and equivalent strain field on the inertial friction welding process are obtained.

[0092] Adjustments were made based on the rotational speed, upsetting pressure, and moment of inertia of the inertial friction welding at the fixed and rotating ends. Simulations were then performed again to obtain the altered temperature field profile, axial shortening, and stress concentration. The effects of different process parameters on the temperature field, stress distribution, and displacement contour plot of the double joint were then obtained.

[0093] In one exemplary embodiment, a three-dimensional model of a double connector is created using SolidWorks. The three-dimensional model of the double connector mainly includes a fixed end and a rotating end, such as... Figure 2 The image shows the fixed end, which is divided into three sections with a total length of 275mm. From left to right, the first section has a length of 120mm and a diameter of 89mm, without taper. The second section is 130mm long with a 7° taper. The third section has the same diameter (57mm) as the rightmost section of the second section and a length of 25mm. The first section provides space for the rotating fixture used in inertial friction welding. The third section is designed to weld to the rotating end and facilitate the removal of inclusions or molten metal as flash, resulting in better mechanical properties.

[0094] Rotating end such as Figure 3 As shown, the rotating end is divided into three sections with a total length of 275mm. From left to right, the three sections are: the first section has a length of 25mm and a diameter of 57.07mm, without taper; the second section has a length of 130mm and a taper of 7°; the third section has the same diameter (25.1mm) as the rightmost section of the second section and a length of 120mm. The first section is designed for connection with the fixed end, while the third section is designed as a fixing fixture for inertial friction welding.

[0095] The graph showing the change in Young's modulus with temperature, calculated by JMatpro software, is shown below. Figure 4 As shown, JMatpro software calculates the material properties of molten metal at high temperatures, outputting curves for density p, specific heat capacity cp, viscosity μ, surface tension σ, and thermal conductivity λ. The specific calculation process is as follows: input the alloy composition; select the required database in JMatpro software and input the metal alloy composition; set the environmental conditions; select the calculation temperature range, and calculate the curves showing the changes in the material properties.

[0096] like Figure 5 The figure shows the temperature field variation over time during the tapered plane inertial friction welding process. Figure 5 Figure (a) shows the temperature field change over time during the initial friction stage. Figure 5 Figure (b) and Figure 5 Figure (c) shows the temperature field change over time during the unstable friction stage. Figure 5 (d) diagram and Figure 5 Figure (e) shows the temperature field variation over time during the steady friction phase. Figure 5 Figure (f) shows the temperature field change over time during the upsetting pressure maintenance stage.

[0097] The initial friction stage generally refers to the period after the drive system stops working, when the heating rate of the rotating end and the welding interface that begins to contact each other accelerates (the rotating end and the moving end rub against each other under the action of rotation and upsetting force, and the internal energy of the metal at the contact surface begins to be converted into heat energy mainly by dry friction. Under the action of upsetting pressure, the weld joint heats up rapidly. As the friction continues, the friction pressure increases continuously, and the temperature also gradually increases. The highest temperature occurs at the upper and lower contact parts of the fixed end and the top and bottom of the rotating end of the welding interface).

[0098] During the unstable friction stage, the temperature field of the weld joint is characterized by a rapid increase in joint temperature. The metal material at the weld interface undergoes significant plastic deformation in a short period of time, combining with oxides and inclusions present at the interface. Under the upsetting force, they are all squeezed together, forming flash at the interface. During the workpiece rotation, frictional heat is generated at the joint interface, with the central region of the interface rapidly heating up to the highest temperature, resulting in uneven radial temperature distribution at the interface, characterized by a high temperature at the center and a low temperature at the edges.

[0099] During the stable friction phase, temperature changes are in a relatively stable state, such as... Figure 5 As shown in Figure (d), the joint is in a high-temperature, uniform, and stable state because the kinetic energy of the rotating end is being continuously consumed, causing the rotational speed of the rotating end to gradually decrease, and the rate of temperature rise of the joint to gradually decrease. At the same time, the heat transfer process is still occurring, so the contact surface of the two welded parts is still deformed at high temperature, producing ductile metal that continues to form flash, and the temperature field reaches dynamic equilibrium.

[0100] During the upsetting pressure maintenance phase, some of the heat from the ductile metal is carried away as the flash is continuously extruded. Simultaneously, as the rotational speed decreases, the rate of heat generation and loss in the entire welded joint becomes almost identical, reaching a dynamic equilibrium. When the flywheel's kinetic energy is exhausted and the rotating end stops rotating, the fixed end remains in contact with the rotating end under upsetting pressure, entering the pressure holding phase. In this phase, the joint's heat energy is transferred to the environment, fixtures, and equipment through thermal radiation and conduction. After holding the pressure for 20 seconds, the upsetting force is released, thus completing the welding. Finally, the flash is formed under the combined action of upsetting pressure and frictional stress.

[0101] The process parameters of the rotating end and the fixed end were changed and simulated respectively: rotation speed: 650, 700, 750; upsetting pressure: 520, 550, 580.

[0102] Two factors, rotational speed and upsetting pressure, were set, each with three levels, and an orthogonal experimental table was constructed. Table 1 shows the orthogonal experimental diagram for the two-factor, three-level experiment.

[0103] Table 1

[0104]

[0105]

[0106] Based on Table 1, an empirical equation for fitting is established, as follows: Figure 6 As shown. In Figure 6 In this equation, X represents the rotational speed, y represents the upsetting pressure, and z represents the axial shortening. Based on this, a fitting empirical equation is established. The relationship between the axial shortening and the process parameters is determined according to the fitted empirical equation, and the process erosion of inertial friction welding is completed based on this.

[0107] This invention establishes a three-dimensional model of the inertial friction welding process. Compared to the traditional cylindrical model, this model uses three fixed and rotating ends of different sizes. Both the fixed and rotating ends have a 7° conical surface, which facilitates the extrusion of excessively melted harmful substances and inclusions as flash. Furthermore, the model dimensions are designed to meet the stress joint requirements of riser systems in the context of offshore oil extraction. Combining the frictional characteristics and rotational form of inertial friction welding, the three-dimensional transient thermal model of the inertial friction welding process considers heat transfer processes such as heat conduction, convection, and radiation to perform transient thermo-mechanical coupling analysis of the temperature field. This yields the influence of rotational speed, upsetting pressure, and moment of inertia on the temperature field evolution in four stages: the initial friction stage, the unstable friction stage, the stable friction stage, and the upsetting pressure maintenance stage. Simultaneously, the results of the axial stress field, equivalent stress field, and equivalent strain field of the fixed and rotating ends of the tapered joint model under the influence of process parameters during the welding process are obtained. This provides a theoretical basis for studying the separation of the upper and lower joints and the initial stress concentration during inertial friction welding. It can also predict the direction and location of the maximum stress and deformation during the welding process, as well as the separation ratio affected by process parameters. Furthermore, the temperature field can be used to predict the generation of microstructure and defects. Ultimately, this lays the foundation for establishing an effective process method to control deformation in inertial friction welding and obtaining high-precision, high-performance formed parts.

[0108] When applying the numerical simulation method for the tapered plane model of inertial friction welding provided by this invention, it is not necessary to consider... Figure 1 The steps shown are executed in sequence. The specific execution order of each step can be determined as needed, and this invention does not impose any restrictions on it.

[0109] The above describes a numerical simulation method for a tapered plane model of inertial friction welding, provided by one or more embodiments of the present invention. Based on the same idea, the present invention also provides a corresponding numerical simulation device for a tapered plane model of inertial friction welding, such as... Figure 7 As shown.

[0110] Figure 7 A schematic diagram of a numerical simulation device for a tapered plane model of inertial friction welding provided by the present invention includes:

[0111] The first building module 701 is used to establish a three-dimensional model of the double joint during the inertial friction welding process; the three-dimensional model of the double joint includes a fixed end and a rotating end.

[0112] The second construction module 702 is used to establish a transient thermo-coupling module. It imports a fixed end and a rotating end into the geometry of the transient thermo-coupling module and assigns the fixed end and the rotating end to the corresponding metal alloy material. The fixed end and the rotating end are discretized into multiple meshes respectively. The transient thermo-coupling module handles the transient process of thermo-coupling effect in the inertial friction welding process.

[0113] The adjustment module 703 is used to adjust the mesh positions corresponding to the fixed end and the rotating end for the purpose of fitting the fixed end and the rotating end together, and to set the thermal boundary conditions between the fixed end and the rotating end.

[0114] The simulation module 704 is used to obtain the influence of different process parameters on the temperature field, stress distribution and displacement cloud map of the double joint by modifying the process parameters of the fixed end and the rotating end and performing simulation; the process parameters include rotation speed, upsetting pressure and rotational inertia.

[0115] Specific limitations regarding the numerical simulation device for a tapered plane model of inertial friction welding can be found in the above-described limitations of the numerical simulation method for a tapered plane model of inertial friction welding, and will not be repeated here. Each module in the aforementioned numerical simulation device for a tapered plane model of inertial friction welding can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0116] The present invention also provides a computer-readable storage medium storing a computer program that can be used to execute the above-described... Figure 1 A numerical simulation method for a tapered plane model of inertial friction welding is provided.

[0117] The present invention also provides Figure 8 The schematic diagram of the computer device shown is as follows: Figure 8As shown, at the hardware level, this computer device includes a processor, internal bus, network interface, memory, and non-volatile memory, and may also include other hardware required for business operations. The processor reads the corresponding computer program from the non-volatile memory into memory and then executes it to achieve the above. Figure 1 A numerical simulation method for a tapered plane model of inertial friction welding is provided.

[0118] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided by this invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0119] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this invention.

Claims

1. A numerical simulation method for a tapered plane model of inertial friction welding, characterized in that, include: A three-dimensional model of the double joint during inertial friction welding is established; the three-dimensional model of the double joint includes a fixed end and a rotating end; A transient thermo-coupling module is established. The fixed end and the rotating end are imported into the geometry of the transient thermo-coupling module, and the fixed end and the rotating end are made of corresponding metal alloy materials. The fixed end and the rotating end are discretized into multiple grids respectively. The transient thermo-coupling module handles the transient process of thermo-coupling in the inertial friction welding process; With the aim of fitting the fixed end and the rotating end together, the grid positions corresponding to the fixed end and the rotating end are adjusted, and the thermal boundary conditions between the fixed end and the rotating end are set; the parallel distances of the x, y, and z axes of the fixed end and the rotating end are adjusted and translated, so that the welding surfaces of the fixed end and the rotating end are fitted together so that the fixed end and the rotating end can directly rotate and rub against each other; The thermal boundary conditions include thermal conduction between the fixed end and the rotating end, as well as thermal convection between the joint and the surrounding environment. By modifying the process parameters of the fixed end and the rotating end and performing simulation, the temperature field, stress field and displacement cloud diagram of the double joint are obtained; the process parameters include rotational speed, upsetting pressure and moment of inertia; In the "Analysis Step" module of the ABAQUS software, the simulation process can be adjusted by setting different step sizes; The evolution of the temperature field during inertial friction welding at key nodes is described in four stages: initial friction stage, unstable friction stage, stable friction stage, and upsetting pressure maintenance stage. The sensitivity of various parameters to the temperature field is analyzed and compared at selected key nodes. High-temperature points at the upper and lower joints of the formed part are marked, including the influence of rotational speed, upsetting pressure, and moment of inertia on the temperature field changes of the upper and lower joints. The changes in heating rate and heat flux density during the friction process are calculated. The stress field is solved to obtain the axial stress field, equivalent stress field, and equivalent stress field during the inertial friction welding process. The effects of variable field conditions are investigated. Based on adjustments to the rotational speed, upsetting pressure, and moment of inertia of the inertial friction welding at both the fixed and rotating ends, simulations are performed again to obtain the altered temperature field profile, axial shortening, and stress concentration. This yields the influence of different process parameters on the temperature field, stress distribution, and displacement contour plot of the double-joint. Furthermore, by adjusting the upsetting pressure at the fixed end and the rotational speed and moment of inertia at the rotating end during inertial friction welding, simulations are performed again to obtain the altered temperature field profile, axial shortening, and stress concentration. This demonstrates the influence of different process parameters on the temperature field, stress distribution, and displacement contour plot of the double-joint.

2. The method as described in claim 1, characterized in that, Discretizing the fixed end and the rotating end into multiple grids respectively includes: The fixed end and the rotating end are discretized into multiple grids along the length, width and height directions, and the grids are regular hexahedral units.

3. The method as described in claim 1, characterized in that, The inertial friction welding process is divided into an initial friction stage, an unstable friction stage, a stable friction stage, and a top pressure maintenance stage.

4. The method as described in claim 1, characterized in that, The method further includes: In the initial friction stage of the inertial friction welding process, the Coulomb model is first used to describe the friction behavior. When the initial friction stress is greater than the shear yield strength of the material, the steady friction stage is entered, and the shear model is used to describe the friction behavior.

5. The method as described in claim 4, characterized in that, The calculation formula for the Coulomb model is as follows: ； in, The initial stage frictional stress, The coefficient of friction, It is normal stress. The relative velocity of the weldment; The calculation formula for the shear model is: ； in, To stabilize the frictional stress during the friction phase, The shear friction factor, The shear yield strength of the material. The relative velocity of the weldment.

6. The method as described in claim 1, characterized in that, The inertial friction welding process is divided into an initial friction stage, an unstable friction stage, a stable friction stage, and a top pressure maintenance stage.

7. The method as described in claim 6, characterized in that, The friction torque in the inertial friction welding process is calculated as follows: ； in, M For frictional torque, r Let the node radius be 1. For frictional stress, It is the ratio of the circumference to the diameter. Let be the node radius at the top of the rotating end. The radius of the node at the contact point of the rotating end.

8. The method as described in claim 1, characterized in that, The method further includes: After setting the thermal boundary conditions between the fixed end and the rotating end, the simulation process is adjusted by setting the forming step size.

9. The method as described in claim 1, characterized in that, Both the fixed end and the rotating end are made of titanium alloy; the method further includes: Before establishing the transient thermo-coupling module, select the database corresponding to the titanium alloy material in the physical property change curve calculation software; Input the composition of the titanium alloy material into the database; Set the environmental conditions and select the temperature range for calculation; The property change curve calculation software is used to determine the property parameter change curve of the titanium alloy material.

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