Process parameter optimization method and related device for synchronous rolling stir friction welding

Abstract

The present application discloses a method and related device for optimizing process parameters of stir friction welding with synchronous rolling during welding, which relates to the field of simulation optimization technology. A heat source model is applied in a system finite element model, and a heat transfer simulation is performed on the welding process and cooling process of stir friction welding. Further, in the system finite element model, a contact relationship and a mechanical action relationship between the stirring head finite element model and the weldment finite element model and between the rolling wheel finite element model and the weldment finite element model are applied. The temperature field results obtained by the heat transfer simulation are used as input, and a thermal-mechanical simulation is performed on the welding process, cooling process and fixture release process of stir friction welding with synchronous rolling during welding. The process parameters are adjusted based on the welding stress results and welding deformation results obtained by the thermal-mechanical simulation, so as to determine the optimal process parameters for performing on-the-fly correction control of stir friction welding using synchronous rolling during welding, thereby effectively reducing the welding deformation of stir friction welding.

Description

Technical Field

[0001] The present application relates to the technical field of simulation optimization, and in particular to a method and a related device for optimizing process parameters of synchronous rolling stir friction welding. Background Art

[0002] Friction stir welding (FSW) is a solid-phase joining method. Compared with fusion welding, the residual stress and deformation of friction stir welding are smaller. Although the friction stir welding technology has the characteristics of small deformation, for large-sized thin-walled weldments or special-shaped weldments with thin-walled structures, there is still a large welding deformation that cannot be ignored after welding. How to effectively reduce the welding deformation of friction stir welding is still an important problem that needs to be solved in thin plate welding processing.

[0003] Compared with passive post-weld correction, the welding correction method is a more effective active control method. Important components have very strict requirements on dimensional accuracy, so it is very important to accurately control welding deformation and welding stress. For actual weldments with complex structures, it is very time-consuming and costly to repeatedly debug by relying solely on experience and empirical formulas for a large number of tests. For example, synchronous rolling control during welding is a welding correction method that can reduce welding deformation, but it is time-consuming and costly to rely on experiments to obtain the optimal process parameters for synchronous rolling during welding. With the development of computer technology and numerical calculation methods, effective simulation prediction and process optimization through computer simulation technology is an effective way to achieve process control.

[0004] However, the current residual stress and deformation control technologies are all developed for fusion welding, that is, they all use synchronous rolling with welding to perform on-the-fly correction control on fusion welding, and the current on-the-fly correction simulation methods are all for traditional fusion welding. There are no reports on on-the-fly correction methods for stir friction welding, that is, there is no technology for on-the-fly correction control of stir friction welding using synchronous rolling with welding, and there are no reports on simulation modeling and process optimization methods for this technology. Summary of the invention

[0005] The purpose of this application is to provide a method and related device for optimizing the process parameters of stir friction welding with synchronous rolling during welding, which can determine the optimal process parameters for performing on-weld correction control on stir friction welding using synchronous rolling during welding, and effectively reduce the welding deformation of stir friction welding.

[0006] To achieve the above objectives, this application provides the following solutions:

[0007] In a first aspect, the present application provides a method for optimizing process parameters of synchronous rolling stir friction welding, the method comprising:

[0008] Establishing a system finite element model of synchronous rolling stir friction welding with welding; the system finite element model includes a rolling wheel finite element model, a stirring head finite element model and a weldment finite element model, the rolling wheel finite element model and the stirring head finite element model are both arranged vertically with the weldment finite element model, the rolling wheel finite element model and the stirring head finite element model are both in contact with the upper surface of the weld position of the weldment finite element model, and the rolling wheel finite element model and the stirring head finite element model are arranged at intervals;

[0009] Applying a heat source model to the system finite element model to obtain a system finite element model including the heat source model; the heat source model is a model equivalent to the friction heat generation of an actual stirring head;

[0010] The system finite element model including the heat source model is used to simulate the heat transfer of the friction stir welding process and the cooling process to obtain the temperature field results of the actual weldment; the temperature field results include the temperature field of the actual weldment at each moment during the welding process and the cooling process;

[0011] The contact relationship and mechanical action relationship between the stirring head finite element model and the weldment finite element model, as well as the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model are applied to the system finite element model to obtain a system finite element model including the contact relationship and the mechanical action relationship; the contact relationship between the stirring head finite element model and the weldment finite element model is a frictionless surface-to-surface contact relationship, the mechanical action relationship between the stirring head finite element model and the weldment finite element model is to apply a vertical mechanical force to the stirring head finite element model, the contact relationship between the rolling wheel finite element model and the weldment finite element model is a frictional surface-to-surface contact relationship, and the mechanical action relationship between the rolling wheel finite element model and the weldment finite element model is to apply a vertical mechanical force to the rolling wheel finite element model;

[0012] Taking the temperature field result as input, a system finite element model including contact relationship and mechanical action relationship is used to perform thermal-mechanical simulation on the welding process, cooling process and fixture release process of synchronous rolling stir friction welding, so as to obtain the welding stress result and welding deformation result of the actual weldment; the welding stress result includes the welding stress field of the actual weldment at each moment in the welding process, cooling process and fixture release process; the welding deformation result includes the welding deformation field of the actual weldment at each moment in the welding process, cooling process and fixture release process;

[0013] Determine whether the iteration termination condition is met; if so, use the process parameters used in the current iteration as the optimized process parameters; if not, adjust the process parameters used in the current iteration based on the welding stress result and the welding deformation result, determine the system finite element model of the next iteration and the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model of the next iteration based on the adjusted process parameters, and return to the step of "applying the contact relationship and mechanical action relationship between the stirring head finite element model and the weldment finite element model and the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model in the system finite element model to obtain a system finite element model including the contact relationship and mechanical action relationship"; the process parameters include the distance between the rolling wheel finite element model and the stirring head finite element model, the magnitude of the vertical mechanical force applied to the rolling wheel finite element model, and the friction coefficient between the rolling wheel finite element model and the weldment finite element model.

[0014] In a second aspect, the present application provides a device for optimizing process parameters of synchronous rolling stir friction welding with welding, and the device for optimizing process parameters of synchronous rolling stir friction welding with welding comprises:

[0015] A model building module is used to build a system finite element model of rolling stir friction welding with welding; the system finite element model includes a rolling wheel finite element model, a stirring head finite element model and a weldment finite element model, the rolling wheel finite element model and the stirring head finite element model are both arranged vertically with the weldment finite element model, the rolling wheel finite element model and the stirring head finite element model are both in contact with the upper surface of the weld position of the weldment finite element model, and the rolling wheel finite element model and the stirring head finite element model are arranged at intervals;

[0016] A first applying module is used to apply a heat source model to the system finite element model to obtain a system finite element model including the heat source model; the heat source model is a model equivalent to the friction heat generation of an actual stirring head;

[0017] The first simulation module is used to use a system finite element model including a heat source model to perform heat transfer simulation on the welding process and cooling process of the friction stir welding to obtain a temperature field result of the actual weldment; the temperature field result includes the temperature field of the actual weldment at each moment during the welding process and the cooling process;

[0018] A second applying module is used to apply the contact relationship and mechanical action relationship between the stirring head finite element model and the weldment finite element model, as well as the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model in the system finite element model, to obtain a system finite element model including the contact relationship and the mechanical action relationship; the contact relationship between the stirring head finite element model and the weldment finite element model is a frictionless surface-to-surface contact relationship, the mechanical action relationship between the stirring head finite element model and the weldment finite element model is to apply a vertical mechanical force to the stirring head finite element model, the contact relationship between the rolling wheel finite element model and the weldment finite element model is a frictional surface-to-surface contact relationship, and the mechanical action relationship between the rolling wheel finite element model and the weldment finite element model is to apply a vertical mechanical force to the rolling wheel finite element model;

[0019] The second simulation module is used to use the temperature field result as input, and use the system finite element model including the contact relationship and the mechanical action relationship to perform thermal-mechanical simulation on the welding process, cooling process and fixture release process of the synchronous rolling stir friction welding, so as to obtain the welding stress result and welding deformation result of the actual weldment; the welding stress result includes the welding stress field of the actual weldment at each moment in the welding process, cooling process and fixture release process; the welding deformation result includes the welding deformation field of the actual weldment at each moment in the welding process, cooling process and fixture release process;

[0020] A parameter optimization module is used to determine whether the iteration termination condition is met; if so, the process parameters used in the current iteration are used as the optimized process parameters; if not, the process parameters used in the current iteration are adjusted based on the welding stress result and the welding deformation result, and the system finite element model of the next iteration and the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model of the next iteration are determined based on the adjusted process parameters, and the step of "applying the contact relationship and mechanical action relationship between the stirring head finite element model and the weldment finite element model and the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model in the system finite element model to obtain a system finite element model including the contact relationship and mechanical action relationship" is returned; the process parameters include the distance between the rolling wheel finite element model and the stirring head finite element model, the magnitude of the vertical mechanical force applied to the rolling wheel finite element model, and the friction coefficient between the rolling wheel finite element model and the weldment finite element model.

[0021] In a third aspect, the present application provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-mentioned method for optimizing process parameters of simultaneous rolling stir friction welding.

[0022] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned method for optimizing process parameters of simultaneous rolling stir friction welding.

[0023] In a fifth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the above-mentioned method for optimizing process parameters of simultaneous rolling stir friction welding.

[0024] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0025] The present application provides a method and related device for optimizing process parameters of stir friction welding with simultaneous rolling and friction stir welding. A heat source model is applied to the system finite element model of stir friction welding with simultaneous rolling and friction stir welding, and heat transfer simulation is performed on the welding process and cooling process of stir friction welding to obtain the temperature field result of the actual weldment. On this basis, the contact relationship and mechanical action relationship between the stirring head finite element model and the weldment finite element model, as well as the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model are further applied to the system finite element model of stir friction welding with simultaneous rolling and friction stir welding. With the temperature field result as input, a thermal-mechanical simulation is performed on the welding process, cooling process and fixture release process of stir friction welding with simultaneous rolling and friction stir welding to obtain the welding stress result and welding deformation result of the actual weldment. The process parameters are adjusted based on the welding stress result and welding deformation result, so as to determine the optimal process parameters for on-the-fly correction control of stir friction welding using synchronous rolling and friction stir welding, thereby effectively reducing the welding deformation of stir friction welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic diagram of a method flow chart of a method for optimizing process parameters of friction stir welding with simultaneous rolling provided in Example 1 of the present application.

[0028] Figure 2Schematic diagram of the system geometric structure model of the synchronous rolling stir friction welding provided in Example 1 of the present application.

[0029] Figure 3 A detailed flow chart of a method for optimizing process parameters of friction stir welding with simultaneous rolling provided in Example 1 of the present application.

[0030] Figure 4 A schematic diagram of the functional modules of a process parameter optimization device for simultaneous rolling and friction stir welding provided in Example 2 of the present application.

[0031] Figure 5 A schematic diagram of the structure of a computer device provided in Example 3 of the present application.

[0032] Explanation of symbols:

[0033] 1-Geometry model of rolling wheel; 2-Geometry model of mixing head; 3-Geometry model of weldment; 4-Position of weld. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0035] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0036] Example 1

[0037] like Figure 1 As shown, this embodiment provides a method for optimizing process parameters of synchronous rolling stir friction welding, and the method for optimizing process parameters of synchronous rolling stir friction welding includes:

[0038] S1: Establish a system finite element model of synchronous rolling stir friction welding; the system finite element model includes a rolling wheel finite element model, a stirring head finite element model and a weldment finite element model, the rolling wheel finite element model and the stirring head finite element model are both vertically arranged with respect to the weldment finite element model, the rolling wheel finite element model and the stirring head finite element model are both in contact with the upper surface of the weld position of the weldment finite element model, and the rolling wheel finite element model and the stirring head finite element model are arranged at intervals.

[0039] In S1, a system finite element model of synchronous rolling stir friction welding is established, including:

[0040] (1) Establish the system geometric structure model of simultaneous rolling stir friction welding.

[0041] like Figure 2 As shown, the system geometric structure model of synchronous rolling stir friction welding includes a rolling wheel geometric structure model 1, a stirring head geometric structure model 2 and a weldment geometric structure model 3. The rolling wheel geometric structure model 1 and the stirring head geometric structure model 2 are both vertically arranged with respect to the weldment geometric structure model 3. The rolling wheel geometric structure model 1 and the stirring head geometric structure model 2 are both in contact with the upper surface of the weld position 4 of the weldment geometric structure model 3. The rolling wheel geometric structure model 1 and the stirring head geometric structure model 2 are spaced apart. The spacing between the rolling wheel geometric structure model 1 and the stirring head geometric structure model 2 in the direction of the weld position 4 is consistent with the actual spacing, and the spacing is an adjustable process parameter.

[0042] The structure and size of the rolling wheel geometric structure model 1 are the same as those of the actual rolling wheel. The structure of the stirring head geometric structure model 2 is a cylinder, and the diameter of the stirring head geometric structure model 2 is the same as the diameter of the stirring part of the actual stirring head. The actual stirring head includes a stirring part and a stirring needle. The structure and size of the weldment geometric structure model 3 are the same as those of the actual weldment.

[0043] (2) The rolling wheel geometry model is set as a rigid body model to obtain a rolling wheel finite element model; the stirring head geometry model is set as a rigid body model to obtain a stirring head finite element model; the weldment geometry model is set as a flexible body model, the material properties of the weldment geometry model are set, and the weldment geometry model is meshed to obtain a weldment finite element model; the rolling wheel finite element model, the stirring head finite element model, and the weldment finite element model are combined to form a system finite element model of synchronous rolling stir friction welding.

[0044] The material properties of the weldment geometry model are set, specifically including: setting the material properties of the weldment geometry model according to the actual welding situation, such as aluminum, copper, etc.

[0045] Among them, meshing the weldment geometric structure model specifically includes: dividing the weldment geometric structure model into a first area and a second area, the first area is an area with the weld position as the center line, the length is the same as the length of the weldment geometric structure model and the width is a preset value, and the second area is other areas in the weldment geometric structure model except the first area; meshing the first area according to the principle of equal mesh size, meshing the second area according to the principle that the farther from the weld position, the larger the mesh size, the size of the minimum mesh obtained by dividing the second area is larger than the size of the mesh obtained by dividing the first area.

[0046] In this embodiment, the preset value may be twice the diameter of the stirring portion of the actual stirring head. The sizes of the grids obtained by dividing the first area are all the same, and may be a value not greater than 1 / 10 of the diameter of the stirring portion of the actual stirring head. The sizes of the grids obtained by dividing the second area are different, the size of the smallest grid is greater than the size of the grid obtained by dividing the first area, and the size of the largest grid is not greater than 20 mm.

[0047] S2: applying a heat source model to the system finite element model to obtain a system finite element model including the heat source model; the heat source model is a model equivalent to the friction heat generation of an actual stirring head.

[0048] In S2, the heat source model is a composite heat source consisting of a torus uniformly distributed heat source and a cylindrical uniformly distributed heat source. The axis of the torus uniformly distributed heat source is coaxial with the axis of the cylindrical uniformly distributed heat source, and the upper surfaces of the torus uniformly distributed heat source and the cylindrical uniformly distributed heat source are coplanar, and the upper surface of the cylindrical uniformly distributed heat source is a circular surface.

[0049] The inner radius of the torus-shaped uniformly distributed heat source is the same as the radius of the stirring needle of the actual stirring head, the outer radius of the torus-shaped uniformly distributed heat source is the same as the radius of the stirring part of the actual stirring head, the radius of the cylinder-shaped uniformly distributed heat source is the same as the radius of the stirring needle of the actual stirring head, and the height of the cylinder-shaped uniformly distributed heat source is the same as the height of the stirring needle of the actual stirring head.

[0050] In S2, a heat source model is applied in the system finite element model, specifically including: applying the heat source model to the upper surface and interior of the weldment finite element model of the system finite element model, the annular uniformly distributed heat source of the heat source model is coplanar with the upper surface of the weldment finite element model and is applied to its upper surface, and the cylindrical uniformly distributed heat source of the heat source model is located inside the weldment finite element model and is applied to the cylinder inside it.

[0051] S3: Using a system finite element model including a heat source model, a heat transfer simulation is performed on the welding process and cooling process of the friction stir welding to obtain a temperature field result of the actual weldment; the temperature field result includes the temperature field of the actual weldment at each moment during the welding process and the cooling process.

[0052] Since the weldment finite element simulation model simulates the actual weldment, the temperature field result of the weldment finite element model is the temperature field result of the actual weldment. In S3, the temperature field includes the temperature of each position point of the actual weldment.

[0053] In S3, a system finite element model including a heat source model is used to perform heat transfer simulation on the welding process and cooling process of the stir friction welding to obtain the temperature field result of the actual weldment, specifically including: applying convection boundary conditions and radiation boundary conditions in the system finite element model including the heat source model; controlling the heat source model to move along the weld position at a preset moving speed to simulate the welding process of the stir friction welding, and performing heat transfer analysis at the same time to obtain the temperature field of the actual weldment at each moment in the welding process; after the welding is completed, stopping the application of the heat source model to simulate the cooling process of the stir friction welding, and performing heat transfer analysis at the same time to obtain the temperature field of the actual weldment at each moment in the cooling process.

[0054] During actual welding, a clamp is provided to fix the finite element model of the weldment, and a pad is provided to support the finite element model of the weldment. According to the actual positions of the clamp and the pad, a first convection boundary condition is applied at the positions corresponding to the actual positions of the clamp and the pad in the system finite element model including the heat source model, and a second convection boundary condition and a radiation boundary condition are applied at other positions in the system finite element model including the heat source model, so as to apply convection boundary conditions and radiation boundary conditions in the system finite element model including the heat source model.

[0055] S4: applying the contact relationship and mechanical action relationship between the stirring head finite element model and the weldment finite element model, as well as the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model in the system finite element model to obtain a system finite element model including the contact relationship and the mechanical action relationship; the contact relationship between the stirring head finite element model and the weldment finite element model is a frictionless surface-to-surface contact relationship, the mechanical action relationship between the stirring head finite element model and the weldment finite element model is to apply a vertical mechanical force to the stirring head finite element model, the contact relationship between the rolling wheel finite element model and the weldment finite element model is a frictional surface-to-surface contact relationship, and the mechanical action relationship between the rolling wheel finite element model and the weldment finite element model is to apply a vertical mechanical force to the rolling wheel finite element model.

[0056] S5: Using the temperature field results as input, a system finite element model including contact relationship and mechanical action relationship is used to perform thermal-mechanical simulation on the welding process, cooling process and fixture release process of the synchronous rolling stir friction welding to obtain the welding stress results and welding deformation results of the actual weldment; the welding stress results include the welding stress field of the actual weldment at each moment in the welding process, cooling process and fixture release process; the welding deformation results include the welding deformation field of the actual weldment at each moment in the welding process, cooling process and fixture release process.

[0057] In S5, the welding stress field includes the welding stress at each position point of the actual weldment, and the welding deformation field includes the welding deformation at each position point of the actual weldment.

[0058] In S5, the temperature field results are used as input, and the system finite element model including the contact relationship and the mechanical action relationship is used to perform thermal-mechanical simulation on the welding process, cooling process and fixture release process of the synchronous rolling stir friction welding, so as to obtain the welding stress results and welding deformation results of the actual weldment. Specifically, the following are used: the fixture constraint and the pad constraint are applied in the system finite element model including the contact relationship and the mechanical action relationship, the fixture is used to fix the weldment finite element model, and the pad is used to support the weldment finite element model; at the same time, the rolling wheel finite element model and the stirring head finite element model are controlled to move along the weld position at a preset moving speed to simulate the welding process of the synchronous rolling stir friction welding, and at the same time, the actual weldment is used at each time during the welding process. The temperature field at a certain moment is used as input to perform thermal-mechanical analysis, and the welding stress field and welding deformation field of the actual weldment at each moment in the welding process are obtained; after welding is completed, the finite element model of the rolling wheel and the finite element model of the stirring head are controlled to stop moving at the same time to simulate the cooling process of the synchronous rolling stir friction welding with welding, and at the same time, the temperature field of the actual weldment at each moment in the cooling process is used as input to perform thermal-mechanical analysis, and the welding stress field and welding deformation field of the actual weldment at each moment in the cooling process are obtained; after cooling is completed, the clamp is removed to simulate the clamp release process of the synchronous rolling stir friction welding with welding, and elastic-plastic mechanics analysis is performed at the same time to obtain the welding stress field and welding deformation field of the actual weldment at each moment in the clamp release process.

[0059] Among them, applying fixture constraints and pad constraints specifically includes: setting the partial displacement of the mesh at the location of the fixture and the pad in the weldment finite element model to 0, and the direction of the displacement of 0 is the direction consistent with the action direction of the fixture and the pad. For example, the fixture is used to limit the vertical displacement of the weldment finite element model, then the vertical displacement of the mesh at the location of the fixture in the weldment finite element model is 0.

[0060] S6: Determine whether the iteration termination condition is met; if so, use the process parameters used in the current iteration as the optimized process parameters; if not, adjust the process parameters used in the current iteration based on the welding stress result and the welding deformation result, determine the system finite element model of the next iteration and the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model of the next iteration based on the adjusted process parameters, and return to the step of "applying the contact relationship and mechanical action relationship between the stirring head finite element model and the weldment finite element model and the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model in the system finite element model to obtain a system finite element model including the contact relationship and mechanical action relationship". The process parameters include the distance between the rolling wheel finite element model and the stirring head finite element model, the magnitude of the vertical mechanical force applied to the rolling wheel finite element model, and the friction coefficient between the rolling wheel finite element model and the weldment finite element model.

[0061] In S6, the iteration termination condition is that the change of the maximum welding deformation value between two adjacent iterations meets the requirements, or the process parameters reach the edge of the feasible process window, and the feasible process window is the value range of the process parameters set by the user.

[0062] The change in the maximum welding deformation value between two adjacent iterations meets the requirements as follows:

[0063]

[0064] Among them, u i is the maximum welding deformation value calculated in the i-th iteration, determined according to the welding deformation result of the i-th iteration; u i-1 is the maximum welding deformation value obtained by the i-1th iteration calculation, which is determined according to the welding deformation result of the i-1th iteration; i is the serial number of the analysis calculation, and the above conditions are applied from the second iteration to determine whether the changes meet the requirements.

[0065] like Figure 3 As shown, it is a detailed flow chart of the process parameter optimization method of synchronous rolling stir friction welding of this embodiment. Figure 3 The process parameter optimization method of the friction stir welding with simultaneous rolling during welding of this embodiment is further introduced:

[0066] Step 1: According to the actual situation of synchronous rolling stir friction welding, the geometric structure models of the weldment, the stirring head and the rolling wheel are established respectively, and the rolling wheel geometric structure model, the stirring head geometric structure model and the weldment geometric structure model are obtained. The structures and sizes of the rolling wheel geometric structure model and the weldment geometric structure model are consistent with the actual ones. The structure of the stirring head geometric structure model is simplified to a flat-headed cylinder with the same radius as the stirring part of the actual stirring head. The length of the stirring head geometric structure model and the length of the stirring part can be the same or different. The actual stirring head includes a stirring part and a stirring needle. The stirring part and the stirring needle are both cylinders. The stirring part and the stirring needle are coaxial, and the lower circular surface of the stirring part is connected to the upper circular surface of the stirring needle. The rolling wheel geometric structure model and the stirring head geometric structure model are both set to be perpendicular to the weldment geometric structure model. At the same time, the rolling wheel geometric structure model and the stirring head geometric structure model are both set to contact the upper surface of the weld position of the weldment geometric structure model. The spacing between the rolling wheel geometric structure model and the stirring head geometric structure model in the weld position direction is set to be consistent with the actual one, so as to obtain the system geometric structure model of synchronous rolling stir friction welding.

[0067] Step 2: Establish a system finite element model of rolling stir friction welding with simultaneous welding, which includes a finite element model of a stirring head and a finite element model of a rolling wheel. Set the rolling wheel geometry model and the stirring head geometry model as rigid body models, without meshing, to obtain the rolling wheel finite element model and the stirring head finite element model. Set the weldment geometry model as a flexible body model, set the material properties of the weldment geometry model, determine the meshing strategy of the weldment geometry model based on the size of the stirring part of the actual stirring head of the friction stir welding, and establish a multi-scale finite element mesh model of the weldment geometry model to obtain the weldment finite element model. The rolling wheel finite element model, the stirring head finite element model, and the weldment finite element model constitute the system finite element model of rolling stir friction welding with simultaneous welding. When meshing the weldment geometry model, the fine mesh area (i.e., the first area) of the weldment geometry model is determined to be an area with the weld position as the center line, the length being the same as the length of the weldment geometry model, and the width being twice the diameter of the stirring portion of the actual stirring head (i.e., the preset value). Three-dimensional fine meshes are divided in this area, and the mesh size is not greater than 1 / 10 of the diameter of the stirring portion of the actual stirring head. In the weldment geometry model, the area other than the fine mesh area (i.e., the second area) is divided into transitional meshes from dense to sparse as the distance from the weld position increases, the size of the smallest mesh is greater than the size of the mesh obtained by the first area, and the size of the largest mesh is not greater than 20 mm.

[0068] Step 3: Determine the heat source model based on the welding characteristics of friction stir welding. The heat source model is a composite heat source composed of a torus uniformly distributed heat source and a cylindrical uniformly distributed heat source. The torus uniformly distributed heat source is coaxial with the cylindrical uniformly distributed heat source, and the torus uniformly distributed heat source and the upper circular surface of the cylindrical uniformly distributed heat source are coplanar. The inner radius of the torus uniformly distributed heat source is consistent with the radius of the stirring needle of the actual stirring head, the outer radius is consistent with the radius of the stirring part of the actual stirring head, and the radius and height of the cylindrical uniformly distributed heat source are consistent with the radius and height of the stirring needle of the actual stirring head.

[0069] Step 4: For the system finite element model established in step 2, apply the composite heat source determined in step 3 according to the actual welding process to obtain a system finite element model including the heat source model; control the moving speed of the heat source model, apply convection boundary conditions and radiation boundary conditions according to the position of the pad and the fixture, conduct heat transfer analysis of the welding process and cooling process of stir friction welding, and obtain the temperature field results of the actual weldment in the welding process and cooling process.

[0070] Step 5: In the system finite element model established in step 2, the contact relationship and mechanical action relationship between the stirring head finite element model and the weldment finite element model are applied. In this embodiment, the function of the stirring head finite element model is to provide a vertical mechanical force on the weldment finite element model. Therefore, according to the actual control method (displacement control or force control), a vertical fixed displacement or a vertical concentrated force is applied to the stirring head finite element model to complete the application of the mechanical action relationship between the stirring head finite element model and the weldment finite element model. At the same time, the relationship between the stirring head finite element model and the weldment finite element model is simplified to a frictionless surface-to-surface contact relationship, wherein the normal direction of the contact surface is a hard contact without penetration behavior, and the tangent direction of the contact surface is a frictionless contact, thereby completing the application of the contact relationship between the stirring head finite element model and the weldment finite element model.

[0071] Step 6: In the system finite element model established in step 5, the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model are applied. In this embodiment, the role of the rolling wheel finite element model is to provide its dual role of "rolling" and "pressing" on the weldment finite element model. Therefore, according to the actual control method (displacement control or force control), a vertical fixed displacement or a vertical concentrated force is applied to the rolling wheel finite element model to complete the application of the mechanical action relationship between the rolling wheel finite element model and the weldment finite element model. At the same time, a surface-to-surface contact relationship with friction is set between the rolling wheel finite element model and the weldment finite element model, wherein the normal direction of the contact surface is a hard contact without penetration behavior, the tangent direction of the contact surface is a friction contact, and the friction coefficient is determined by the actual material, thereby completing the application of the contact relationship between the rolling wheel finite element model and the weldment finite element model.

[0072] Step 7: For the system finite element model including contact relationship and mechanical action relationship established in step 6, according to the actual welding clamping situation, the clamp constraint and pad constraint are applied. According to the actual welding situation, the moving speed of the stirring head finite element model is given, and the speed magnitude and direction are consistent with the movement of the heat source model in step 4. The rotational freedom of the rolling wheel finite element model is released, and the moving speed of the rolling wheel finite element model is given. The speed magnitude and direction are consistent with the movement of the heat source model in step 4. Mechanical analysis software is applied, combined with the temperature field results obtained in step 4, to perform thermal-mechanical analysis, and calculate the welding stress results and welding deformation results of the actual weldment. Manually analyze the changes in welding stress and welding deformation during welding, and manually analyze the influence mechanism of rolling on welding stress and welding deformation, and formulate a preliminary optimization plan to reduce welding deformation.

[0073] Step 8: According to the preliminary optimization plan, adjust the rolling process parameters (including the magnitude of the vertical mechanical force applied to the rolling wheel finite element model, the distance between the rolling wheel finite element model and the stirring head finite element model, and the tangential friction coefficient between the rolling wheel finite element model and the weldment finite element model), and perform analysis and calculation again. If the change in welding deformation meets the requirements or the process parameters reach the edge of the feasible process window, the process optimization is completed. If it does not meet the requirements and the process parameters are within the feasible process window, continue to modify the process parameters.

[0074] Although the friction stir welding technology has the characteristic of small deformation, it still produces large welding deformation for large-sized thin-walled weldments or special-shaped weldments with thin-walled structures. Synchronous rolling control with welding is a technology that can reduce welding deformation, but it requires experiments to obtain the best process parameters, which is time-consuming and costly. Therefore, effective simulation prediction and process optimization through computer simulation technology is an effective way to achieve process control. This embodiment is based on the actual situation of synchronous rolling stir friction welding during welding and on the theory of thermo-elastic-plastic solid mechanics to establish a system finite element model including a weldment finite element model, a stirring head finite element model and a rolling wheel finite element model. In the system finite element model, the stirring head finite element model and the rolling wheel finite element model are rigid bodies, and the weldment finite element model is a flexible body. Contact relationships and mechanical action relationships are established between the weldment finite element model and the stirring head finite element model, and between the weldment finite element model and the rolling wheel finite element model. Specifically, a frictionless contact relationship is established between the stirring head finite element model and the weldment finite element model, and a vertical mechanical action relationship is established between the stirring head finite element model and the weldment finite element model by applying a vertical fixed displacement or a vertical concentrated force to the stirring head finite element model, and a friction contact relationship is established between the rolling wheel finite element model and the weldment finite element model, and a vertical fixed displacement or a vertical concentrated force is applied to the rolling wheel finite element model to release the rotational freedom of the rolling wheel finite element model and establish a rolling wheel finite element model. The vertical and tangential mechanical action relationship between the finite element model and the weldment finite element model is used to realize the dual effects of rolling and pressing of the rolling wheel finite element model on the weldment finite element model. Since the effects between the rolling wheel finite element model and the weldment finite element model and the effects between the stirring head finite element model and the weldment finite element model are consistent with the actual situation, a high-fidelity method for predicting the welding stress and welding deformation of synchronous rolling stir friction welding is designed, and a process parameter optimization method for synchronous rolling stir friction welding is established based on this high-fidelity method. Firstly, a surface-body composite heat source model of stir friction welding is applied to the weldment geometric structure model, and heat transfer analysis is performed to calculate the temperature field results of the actual weldment. On this basis, a thermo-mechanical analysis is performed on the system finite element model including the stirring head finite element model and the rolling wheel finite element model, and the welding stress results and welding deformation results of the actual weldment are calculated. The rolling process parameters are optimized based on the welding stress results and welding deformation results, and the optimal process parameters are obtained by continuous iteration.

[0075] The present embodiment also provides an application scenario, and the application scenario applies the above-mentioned process parameter optimization method of synchronous rolling stir friction welding with welding. Specifically: the process parameter optimization method of synchronous rolling stir friction welding with welding provided in the present embodiment can be applied in the scenario of processing weldments using the synchronous rolling stir friction welding process with welding, and the scenario includes a process parameter optimization link and an actual welding link. The process parameter optimization method of synchronous rolling stir friction welding with welding provided in the present embodiment belongs to the process parameter optimization link, and the optimal process parameters obtained in the process parameter optimization link enter the actual welding link. In the actual welding link, the weldment is actually processed according to the optimal process parameters, thereby reducing the welding deformation of the weldment and improving the welding effect.

[0076] The existing simulation methods for welding correction are all for traditional fusion welding, while this embodiment is for the welding synchronous rolling technology of stir friction welding. Based on the theory of thermoelastic-plastic solid mechanics, a high-fidelity prediction method for welding deformation and a process parameter optimization method thereof are designed. The advantages of this method are:

[0077] (1) In terms of simulation analysis of stir friction welding: Currently, many welding deformation prediction methods can be roughly divided into two types. One is to ignore the vertical mechanical force of the stirring head, which will cause a convex deformation at the weld position, which is inconsistent with the actual situation. The other is to simplify the vertical mechanical force of the stirring head into a uniformly distributed force load for application. This application method will cause the problem of excessive local vertical force at the center of the weld position, which deviates from the actual situation. In the process parameter optimization method of this embodiment, the structural model of the stirring head is added, and the vertical mechanical force of the stirring head finite element model on the weld finite element model is realized through the contact relationship and mechanical action relationship, which is more in line with the actual situation. That is, in the welding simulation process of this embodiment, the vertical mechanical action of the stirring head finite element model on the weld finite element model is added through the contact relationship and mechanical action relationship, which is more in line with the actual welding situation.

[0078] (2) During the welding simulation process, the contact relationship and mechanical action relationship are used to realize the vertical and tangential mechanical effects of the rolling wheel finite element model on the weldment finite element model, thereby realizing its dual effects of rolling and pressing.

[0079] (3) Since the effect of the rolling wheel finite element model on the weldment finite element model and the effect of the stirring head finite element model on the weldment finite element model are more in line with reality, it is a high-fidelity simulation method. Parameter influence analysis and process optimization are carried out based on the high-fidelity simulation method, providing theoretical guidance for the process control of synchronous rolling stir friction welding.

[0080] This embodiment aims to meet the high standards for welding quality in the fields of aerospace, national defense, etc., and based on the theory of thermo-elastic-plastic solid mechanics, a system finite element model of simultaneous rolling and stir friction welding is established, which includes the structural models of the weldment, the stirring head and the rolling wheel. The contact relationship and mechanical action relationship between the finite element model of the weldment and the finite element model of the stirring head, and between the finite element model of the weldment and the finite element model of the rolling wheel are established. Then, a high-fidelity method for predicting the welding stress and welding deformation of simultaneous rolling and stir friction welding is designed, and based on this, a process parameter optimization method for the process is established, which can obtain the optimal process parameters and effectively reduce the welding deformation of stir friction welding.

[0081] Example 2

[0082] Based on the same inventive concept, this embodiment also provides a device for optimizing process parameters of synchronous rolling and friction stir welding with welding for implementing the method for optimizing process parameters of synchronous rolling and friction stir welding with welding involved in embodiment 1. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more embodiments of the device for optimizing process parameters of synchronous rolling and friction stir welding with welding provided below can refer to the limitations of the method for optimizing process parameters of synchronous rolling and friction stir welding with welding above, and will not be repeated here.

[0083] In an exemplary embodiment, Figure 4 As shown, a device for optimizing process parameters of synchronous rolling stir friction welding with welding is provided, and the device for optimizing process parameters of synchronous rolling stir friction welding with welding includes:

[0084] The model building module M1 is used to establish a system finite element model of synchronous rolling stir friction welding; the system finite element model includes a rolling wheel finite element model, a stirring head finite element model and a weldment finite element model, the rolling wheel finite element model and the stirring head finite element model are both vertically arranged with respect to the weldment finite element model, the rolling wheel finite element model and the stirring head finite element model are both in contact with the upper surface of the weld position of the weldment finite element model, and the rolling wheel finite element model and the stirring head finite element model are arranged at intervals.

[0085] The first applying module M2 is used to apply a heat source model to the system finite element model to obtain a system finite element model including the heat source model; the heat source model is a model equivalent to the friction heat generation of an actual stirring head.

[0086] The first simulation module M3 is used to use a system finite element model including a heat source model to perform heat transfer simulation on the welding process and cooling process of stir friction welding to obtain the temperature field results of the actual weldment; the temperature field results include the temperature field of the actual weldment at each moment during the welding process and the cooling process.

[0087] The second application module M4 is used to apply the contact relationship and mechanical action relationship between the mixing head finite element model and the weldment finite element model, as well as the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model in the system finite element model to obtain a system finite element model including the contact relationship and the mechanical action relationship; the contact relationship between the mixing head finite element model and the weldment finite element model is a frictionless surface-to-surface contact relationship, the mechanical action relationship between the mixing head finite element model and the weldment finite element model is to apply a vertical mechanical force to the mixing head finite element model, the contact relationship between the rolling wheel finite element model and the weldment finite element model is a frictional surface-to-surface contact relationship, and the mechanical action relationship between the rolling wheel finite element model and the weldment finite element model is to apply a vertical mechanical force to the rolling wheel finite element model.

[0088] The second simulation module M5 is used to use the temperature field results as input, and use the system finite element model including contact relationship and mechanical action relationship to perform thermal-mechanical simulation on the welding process, cooling process and fixture release process of synchronous rolling stir friction welding, so as to obtain the welding stress results and welding deformation results of the actual weldment; the welding stress results include the welding stress field of the actual weldment at each moment in the welding process, cooling process and fixture release process; the welding deformation results include the welding deformation field of the actual weldment at each moment in the welding process, cooling process and fixture release process.

[0089] The parameter optimization module M6 is used to determine whether the iteration termination condition is met; if so, the process parameters used in the current iteration are used as the optimized process parameters; if not, the process parameters used in the current iteration are adjusted based on the welding stress results and the welding deformation results, and the system finite element model of the next iteration and the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model of the next iteration are determined based on the adjusted process parameters, and the step of "applying the contact relationship and mechanical action relationship between the stirring head finite element model and the weldment finite element model and the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model in the system finite element model to obtain a system finite element model including the contact relationship and mechanical action relationship" is returned; the process parameters include the distance between the rolling wheel finite element model and the stirring head finite element model, the magnitude of the vertical mechanical force applied to the rolling wheel finite element model, and the friction coefficient between the rolling wheel finite element model and the weldment finite element model.

[0090] Example 3

[0091] A computer device comprises: a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the process parameter optimization method for simultaneous rolling stir friction welding as described in Example 1.

[0092] The internal structure diagram of a computer device can be shown as Figure 5 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for optimizing process parameters of synchronous rolling stir friction welding with welding is implemented.

[0093] Those skilled in the art will understand that Figure 5 The structure shown in the figure is only a block diagram of a part of the structure related to the present application scheme, and does not constitute a limitation on the computer device to which the present application scheme is applied. The specific computer device may include Figure 5 More or fewer components may be shown, or certain components may be combined, or may have a different arrangement of components.

[0094] Example 4

[0095] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the process parameter optimization method for synchronous rolling stir friction welding described in Example 1.

[0096] Example 5

[0097] A computer program product includes a computer program, which, when executed by a processor, implements the process parameter optimization method for synchronous rolling stir friction welding described in Example 1.

[0098] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0099] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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 specification.

[0100] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for optimizing process parameters of friction stir welding with rolling during welding, characterized in that: The process parameter optimization method of synchronous rolling stir friction welding comprises: Establishing a system finite element model of synchronous rolling stir friction welding with welding; the system finite element model includes a rolling wheel finite element model, a stirring head finite element model and a weldment finite element model, the rolling wheel finite element model and the stirring head finite element model are both arranged vertically with the weldment finite element model, the rolling wheel finite element model and the stirring head finite element model are both in contact with the upper surface of the weld position of the weldment finite element model, and the rolling wheel finite element model and the stirring head finite element model are arranged at intervals; Applying a heat source model to the system finite element model to obtain a system finite element model including the heat source model; the heat source model is a model equivalent to the friction heat generation of an actual stirring head; The system finite element model including the heat source model is used to simulate the heat transfer of the friction stir welding process and the cooling process to obtain the temperature field results of the actual weldment; the temperature field results include the temperature field of the actual weldment at each moment during the welding process and the cooling process; The contact relationship and mechanical action relationship between the stirring head finite element model and the weldment finite element model, as well as the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model are applied to the system finite element model to obtain a system finite element model including the contact relationship and the mechanical action relationship; the contact relationship between the stirring head finite element model and the weldment finite element model is a frictionless surface-to-surface contact relationship, the mechanical action relationship between the stirring head finite element model and the weldment finite element model is to apply a vertical mechanical force to the stirring head finite element model, the contact relationship between the rolling wheel finite element model and the weldment finite element model is a frictional surface-to-surface contact relationship, and the mechanical action relationship between the rolling wheel finite element model and the weldment finite element model is to apply a vertical mechanical force to the rolling wheel finite element model; Taking the temperature field result as input, a system finite element model including contact relationship and mechanical action relationship is used to perform thermal-mechanical simulation on the welding process, cooling process and fixture release process of synchronous rolling stir friction welding, so as to obtain the welding stress result and welding deformation result of the actual weldment; the welding stress result includes the welding stress field of the actual weldment at each moment in the welding process, cooling process and fixture release process; the welding deformation result includes the welding deformation field of the actual weldment at each moment in the welding process, cooling process and fixture release process; Determine whether the iteration termination condition is met; if so, use the process parameters used in the current iteration as the optimized process parameters; if not, adjust the process parameters used in the current iteration based on the welding stress result and the welding deformation result, determine the system finite element model of the next iteration and the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model of the next iteration based on the adjusted process parameters, and return to the step of "applying the contact relationship and mechanical action relationship between the stirring head finite element model and the weldment finite element model and the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model in the system finite element model to obtain a system finite element model including the contact relationship and mechanical action relationship"; the process parameters include the distance between the rolling wheel finite element model and the stirring head finite element model, the magnitude of the vertical mechanical force applied to the rolling wheel finite element model, and the friction coefficient between the rolling wheel finite element model and the weldment finite element model.

2. The process parameter optimization method of synchronous rolling stir friction welding according to claim 1 is characterized in that: The system finite element model of synchronous rolling stir friction welding is established, including: Establish a system geometric structure model of synchronous rolling stir friction welding; the system geometric structure model includes a rolling wheel geometric structure model, a stirring head geometric structure model and a weldment geometric structure model, the rolling wheel geometric structure model and the stirring head geometric structure model are both arranged vertically to the weldment geometric structure model, the rolling wheel geometric structure model and the stirring head geometric structure model are both in contact with the upper surface of the weld position of the weldment geometric structure model, and the rolling wheel geometric structure model and the stirring head geometric structure model are arranged at intervals; the structure and size of the rolling wheel geometric structure model are the same as those of the actual rolling wheel; the structure of the stirring head geometric structure model adopts a cylinder, and the diameter of the stirring head geometric structure model is the same as the diameter of the stirring part of the actual stirring head; the structure and size of the weldment geometric structure model are the same as those of the actual weldment; Setting the rolling wheel geometric structure model as a rigid body model to obtain a rolling wheel finite element model; Setting the geometric structure model of the stirring head to a rigid body model, and obtaining a finite element model of the stirring head; Setting the weldment geometry model as a flexible body model, setting material properties of the weldment geometry model, and meshing the weldment geometry model to obtain a weldment finite element model; The rolling wheel finite element model, the stirring head finite element model and the weldment finite element model are combined into a system finite element model of synchronous rolling stir friction welding.

3. The process parameter optimization method of synchronous rolling stir friction welding according to claim 2 is characterized in that: Meshing the weldment geometric structure model includes: Dividing the weldment geometric structure model into a first area and a second area, wherein the first area is an area with the weld position as the center line, a length the same as the length of the weldment geometric structure model and a width of a preset value, and the second area is other areas of the weldment geometric structure model except the first area; The first area is meshed according to the principle of equal mesh size, and the second area is meshed according to the principle that the farther away from the weld position, the larger the mesh size; the size of the minimum mesh obtained by dividing the second area is larger than the size of the mesh obtained by dividing the first area.

4. The process parameter optimization method of synchronous rolling stir friction welding according to claim 1 is characterized in that: The heat source model is a composite heat source composed of a torus-uniformly distributed heat source and a cylindrical uniformly distributed heat source, the axis of the torus-uniformly distributed heat source is coaxial with the axis of the cylindrical uniformly distributed heat source, and the torus-uniformly distributed heat source and the upper surface of the cylindrical uniformly distributed heat source are coplanar, and the upper surface of the cylindrical uniformly distributed heat source is a circular surface; The inner radius of the annular surface uniformly distributed heat source is the same as the radius of the stirring needle of the actual stirring head, and the outer radius of the annular surface uniformly distributed heat source is the same as the radius of the stirring part of the actual stirring head; The radius of the cylindrical uniformly distributed heat source is the same as the radius of the stirring needle of the actual stirring head, and the height of the cylindrical uniformly distributed heat source is the same as the height of the stirring needle of the actual stirring head.

5. The process parameter optimization method of synchronous rolling stir friction welding according to claim 1 is characterized in that: The system finite element model including the heat source model is used to simulate the heat transfer of the friction stir welding process and the cooling process to obtain the temperature field results of the actual weldment, including: Apply convection boundary conditions and radiation boundary conditions in the system finite element model including the heat source model; Controlling the heat source model to move along the weld position at a preset moving speed to simulate the friction stir welding process, and simultaneously performing heat transfer analysis to obtain the temperature field of the actual weldment at each moment during the welding process; After welding is completed, the heat source model is stopped to simulate the cooling process of the friction stir welding, and heat transfer analysis is performed at the same time to obtain the temperature field of the actual weldment at each moment during the cooling process.

6. The process parameter optimization method of synchronous rolling stir friction welding according to claim 1 is characterized in that: Taking the temperature field results as input, the system finite element model including contact relationship and mechanical action relationship is used to perform thermal-mechanical simulation on the welding process, cooling process and fixture release process of synchronous rolling stir friction welding, and the welding stress results and welding deformation results of the actual weldment are obtained, including: Apply fixture constraints and pad constraints to the system finite element model containing contact relationships and mechanical action relationships. The fixture is used to fix the weldment finite element model, and the pad is used to support the weldment finite element model. At the same time, the rolling wheel finite element model and the stirring head finite element model are controlled to move along the weld position at a preset moving speed to simulate the welding process of synchronous rolling and stirring friction welding, and at the same time, the temperature field of the actual weldment at each moment in the welding process is used as input to perform thermal-mechanical analysis to obtain the welding stress field and welding deformation field of the actual weldment at each moment in the welding process; After welding is completed, the rolling wheel finite element model and the stirring head finite element model are controlled to stop moving to simulate the cooling process of the synchronous rolling stir friction welding, and the temperature field of the actual weldment at each moment in the cooling process is used as input to perform thermal-mechanical analysis to obtain the welding stress field and welding deformation field of the actual weldment at each moment in the cooling process; After cooling is completed, the fixture is removed to simulate the fixture release process of synchronous rolling stir friction welding. At the same time, elastic-plastic mechanical analysis is performed to obtain the welding stress field and welding deformation field of the actual weldment at each moment during the fixture release process.

7. A device for optimizing process parameters of friction stir welding with rolling during welding, characterized in that: The process parameter optimization device for synchronous rolling stir friction welding comprises: A model building module is used to build a system finite element model of rolling stir friction welding with welding; the system finite element model includes a rolling wheel finite element model, a stirring head finite element model and a weldment finite element model, the rolling wheel finite element model and the stirring head finite element model are both arranged vertically with the weldment finite element model, the rolling wheel finite element model and the stirring head finite element model are both in contact with the upper surface of the weld position of the weldment finite element model, and the rolling wheel finite element model and the stirring head finite element model are arranged at intervals; A first applying module is used to apply a heat source model to the system finite element model to obtain a system finite element model including the heat source model; the heat source model is a model equivalent to the friction heat generation of an actual stirring head; The first simulation module is used to use a system finite element model including a heat source model to perform heat transfer simulation on the welding process and cooling process of the friction stir welding to obtain a temperature field result of the actual weldment; the temperature field result includes the temperature field of the actual weldment at each moment during the welding process and the cooling process; A second applying module is used to apply the contact relationship and mechanical action relationship between the stirring head finite element model and the weldment finite element model, as well as the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model in the system finite element model, to obtain a system finite element model including the contact relationship and the mechanical action relationship; the contact relationship between the stirring head finite element model and the weldment finite element model is a frictionless surface-to-surface contact relationship, the mechanical action relationship between the stirring head finite element model and the weldment finite element model is to apply a vertical mechanical force to the stirring head finite element model, the contact relationship between the rolling wheel finite element model and the weldment finite element model is a frictional surface-to-surface contact relationship, and the mechanical action relationship between the rolling wheel finite element model and the weldment finite element model is to apply a vertical mechanical force to the rolling wheel finite element model; The second simulation module is used to use the temperature field result as input, and use the system finite element model including the contact relationship and the mechanical action relationship to perform thermal-mechanical simulation on the welding process, cooling process and fixture release process of the synchronous rolling stir friction welding, so as to obtain the welding stress result and welding deformation result of the actual weldment; the welding stress result includes the welding stress field of the actual weldment at each moment in the welding process, cooling process and fixture release process; the welding deformation result includes the welding deformation field of the actual weldment at each moment in the welding process, cooling process and fixture release process; A parameter optimization module is used to determine whether the iteration termination condition is met; if so, the process parameters used in the current iteration are used as the optimized process parameters; if not, the process parameters used in the current iteration are adjusted based on the welding stress result and the welding deformation result, and the system finite element model of the next iteration and the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model of the next iteration are determined based on the adjusted process parameters, and the step of "applying the contact relationship and mechanical action relationship between the stirring head finite element model and the weldment finite element model and the contact relationship and mechanical action relationship between the rolling wheel finite element model and the weldment finite element model in the system finite element model to obtain a system finite element model including the contact relationship and mechanical action relationship" is returned; the process parameters include the distance between the rolling wheel finite element model and the stirring head finite element model, the magnitude of the vertical mechanical force applied to the rolling wheel finite element model, and the friction coefficient between the rolling wheel finite element model and the weldment finite element model.

8. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the process parameter optimization method for simultaneous rolling stir friction welding as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the process parameter optimization method of synchronous rolling stir friction welding according to any one of claims 1 to 6 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the process parameter optimization method of synchronous rolling stir friction welding according to any one of claims 1 to 6 is implemented.

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