Macro-micro multi-physics field cross-scale bidirectional coupling modeling method and system for laser welding

Abstract

The present invention belongs to the field of laser welding technology, and discloses a method for cross-scale bidirectional coupling modeling of macro-micro multi-physics fields in laser welding. The present invention adopts the diffusion interface theory, considers the macro heat flow information to revise the micro phase field and solute field evolution equations, considers the micro phase and quality information to revise the macro temperature field and flow field evolution equations, and innovatively constructs a macro heat flow-micro phase and quality multi-physics field bidirectional coupling model to achieve macro-micro bidirectional coupling calculations within the same computational domain. This model can overcome the limitations of traditional sharp interface coupling difficulties, and provide a theoretical model basis for achieving accurate prediction of macro-forming and microstructural evolution in the laser welding process. The present invention establishes a macro temperature field / flow field-micro phase field / solute field bidirectional coupling mechanism, proposes a cross-scale data bidirectional collaborative interaction method, and thus proposes a laser welding macro-micro multi-physics field / cross-scale bidirectional coupling modeling method to achieve accurate simulation of macro-micro forming in the laser welding process.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser welding, and in particular relates to a laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method and system. Background Art

[0002] Laser welding offers advantages such as high energy density, fast welding speed, and excellent processing flexibility, providing an effective means for high-quality and efficient manufacturing of high-performance components for major equipment in fields such as rail transit and aerospace. Its high-temperature, transient, and multi-scale characteristics lead to complex macroscopic heat transfer / flow and microstructural evolution behaviors during the welding process, which directly affect the formation and performance of welded joints. Existing experimental methods make it difficult to accurately characterize the macroscopic heat transfer / flow and microstructural evolution behaviors during welding. With the development of computational fluid dynamics / materials science and the improvement of computer performance, numerical simulation technology has provided an effective method for studying the macro- and micro-dynamic evolution processes of laser welding.

[0003] During laser welding, thermal / fluid oscillations in the mushy zone drive the dynamic nucleation and growth of microscopic dendrites. Simultaneously, the microscopic dendrite network and local solute enrichment at the solidification front negatively influence the heat transfer and convection behavior in the mushy zone. Clarifying the multi-physics interactions between the macroscopic temperature-fluid field and the microscopic phase-solute field, and using methods for spatially and temporally asynchronous / heterogeneous data exchange, is fundamental to establishing a macro-micro bidirectional coupled laser welding model.

[0004] The coupling behavior between the macroscopic temperature field and flow field and the microscopic phase field and solute field during laser welding is extremely complex. Current macro-micro multi-physics modeling methods for laser welding mostly rely on a "one-way input" of macroscopic information into the microscopic simulation. These methods use macroscopic heat flow information as input to unidirectionally drive the evolution of the microscopic phase field and solute field, failing to consider the complex interactions between the macroscopic and microscopic multi-physics fields. This results in insufficient simulation accuracy. Furthermore, cross-scale, spatiotemporal, asynchronous / heterogeneous data interaction often relies on a one-way "macro input-micro output" computational architecture, while reverse information interaction (micro input-macro output) remains to be developed.

[0005] Technical problems caused by existing technologies in industrial applications.

[0006] 1. Insufficient simulation accuracy

[0007] Current macro-micro multi-physics modeling methods for laser welding rely primarily on the "one-way input" of macroscopic information into the microscopic simulation. This approach, using macroscopic heat flow information as input, unidirectionally drives the evolution of the microscopic phase and solute fields. This approach ignores the complex interactions between the macroscopic temperature and flow fields and the microscopic phase and solute fields, resulting in significant deviations between the simulation results and the actual welding process, failing to accurately reflect the true physical phenomena.

[0008] 2. Process optimization is limited

[0009] The lack of a modeling method for bidirectional macro-micro coupling limits existing technologies in optimizing laser welding process parameters. Simulations cannot accurately predict the combined impact of different process parameter combinations on welding quality and energy consumption, resulting in process optimization relying on extensive experimentation and experience, which is inefficient and costly.

[0010] 3. Difficulty in equipment design and control

[0011] Existing one-way modeling methods struggle to provide accurate data support for the design and real-time control of laser welding equipment. This lack of a comprehensive understanding of the dynamic interaction between macroscopic and microscopic physical fields makes it difficult to achieve optimal performance in actual operation, impacting the stability and consistency of the welding process.

[0012] 4. Extended R&D cycle

[0013] Due to the limitations of simulation models, the development of new processes and materials requires extensive experimental verification, increasing R&D costs and cycles. The lack of high-precision, bidirectionally coupled modeling tools hinders the rapid iteration and application of new technologies, reducing the efficiency of industrial innovation.

[0014] 5. Not adaptable to changes in complex working conditions

[0015] In actual production, laser welding processes often face complex operating conditions, such as dynamic changes in welding speed, laser power, and environmental conditions. Existing one-way modeling methods struggle to adapt to and accurately simulate these changes in real time, resulting in a lack of effective early warning and adjustment methods for emergencies, impacting production stability and product consistency.

[0016] 6. Low resource utilization efficiency

[0017] Due to inaccurate simulations, existing technologies waste energy and materials. For example, the inability to accurately predict and control heat input leads to excessive energy consumption or excessive material melting, reducing resource efficiency in the overall production process and increasing operating costs.

[0018] Existing macro-micro multi-physics modeling methods for laser welding have significant shortcomings in simulation accuracy, process optimization, equipment design and control, R&D efficiency, handling complex working conditions, and resource utilization. These technical issues limit the widespread application of laser welding technology in high-precision, high-efficiency, and high-reliability applications. They urgently need to be addressed by establishing a more comprehensive and accurate macro-micro bidirectional coupling model to improve overall production efficiency and economic benefits. Summary of the Invention

[0019] In response to the problems existing in the prior art, the present invention provides a macro-micro multi-physical field cross-scale bidirectional coupling modeling method for laser welding.

[0020] The present invention is implemented as follows: a laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method includes:

[0021] Step 1: Based on the principles of nonlinear thermodynamics and fluid dynamics, considering the influence of the macroscopic temperature field and flow field on the phase field, a mathematical model describing the evolution of the microscopic phase field driven by the macroscopic temperature field and flow field is derived;

[0022] The optimized microscopic phase field governing equation is as follows:

[0023]

[0024] Where τ0 represents the relaxation time, k Cu represents the solute equilibrium distribution coefficient of copper element, u Cu represents the dimensionless concentration of copper element, M Cu represents the interpolation function related to the concentration of copper solute, D 1,Cu represents the diffusion coefficient of copper, D l,Li represents the diffusion coefficient of lithium, k Li represents the solute equilibrium distribution coefficient of lithium, u Li represents the dimensionless concentration of lithium element, represents the anisotropy factor, φ represents the phase field, W0 represents the phase field interface thickness, and represents the interpolation function related to the double-well potential and volume free energy, λ represents the coupling coefficient related to the thermodynamic driving force, Δf(T,t) represents the spatiotemporal distribution data of the temperature field obtained by the macro model, f(u,t) represents the spatiotemporal distribution data of the flow field obtained by the macro model, and t represents time;

[0025] Step 2: Based on the momentum conservation equation, considering the effect of fluid flow on solute transport, a mathematical model is established to describe the evolution of the macroscopic flow field and microscopic solute field;

[0026] Step 3: Extract the spatiotemporal distribution data of key parameters such as macro-scale temperature field and flow field;

[0027] Step 4: Describe the free energy density function of the multiphase system in the welding process based on the conservative phase field and gradient flow theory;

[0028] Step 5: Obtain the thermodynamic driving forces of various phases at the microscale in real time based on the substitutional solution model;

[0029] Step 6: Based on the macroscopic model and microscopic simulation established above, combined with the physical scale relationship between the macroscopic and microscopic model time steps, determine the real-time sequential solution method of the model, and construct a macroscopic and microscopic bidirectional coupling model of laser welding that considers macroscopic heat / flow and microscopic phase / quality.

[0030] Furthermore, based on the momentum conservation equation, the influence of fluid flow on solute transport is considered, and a mathematical model describing the evolution of the macroscopic flow field and the microscopic solute field is established:

[0031] The optimized microscopic solute field evolution equation is as follows:

[0032]

[0033] Where, α m represents the material phase fraction, ρ m Indicates the material density, C l represents the concentration of liquid solute, C represents the total solute concentration, D l represents the diffusion coefficient, represents the corrected liquid phase solute concentration, k v is the solute equilibrium distribution coefficient, C s represents the solid phase solute concentration, f l represents the liquid fraction, u represents the velocity, f s represents the solid phase fraction;

[0034] Considering the influence of the microscopic phase field on the macroscopic temperature field, the energy conservation equation is established under the microscopic phase field distribution-mushy region solid phase fraction-solid-liquid phase transition latent heat mapping model;

[0035] The optimized macroscopic temperature field control equation is as follows:

[0036]

[0037] Where, ρ(f s ,c,t) represents the spatial density under different solid fractions, solute concentrations and time steps, h represents the thermal enthalpy, λ T represents the thermal diffusion coefficient, T represents the temperature, and q laser represents the laser heat source, q vap represents evaporative heat dissipation, L represents latent heat of fusion, q rad Indicates radiative heat dissipation.

[0038] Furthermore, considering the influence of microscopic phase field and solute distribution on the macroscopic flow field equation, a macroscopic momentum conservation equation driven by the evolution of the solid fraction and solute distribution in the mushy zone and the thermophysical parameters in the mushy zone is established.

[0039] The optimized macroscopic momentum conservation equation is as follows:

[0040]

[0041] Where p represents pressure, F s represents surface tension, F b represents gravity, S represents the mushy zone constant, P recoil Indicates steam recoil pressure.

[0042] Furthermore, the temporal and spatial distribution data of key parameters such as macro-scale temperature field and flow field are extracted:

[0043] Based on the interlayer interpolation technology of generative adversarial neural networks, a machine learning model is trained to generate double interpolation results from macroscopic heat / flow (mm / ms level) to microscopic temperature gradient-growth rate (um / us level);

[0044] Realize the mapping interaction from macroscopic low temporal and spatial resolution to microscopic high temporal and spatial resolution asynchronous (ms~us) / heterogeneous (mm~um) data;

[0045] Extract the spatiotemporal distribution data of key parameters such as phase field and solute field of microscopic nonlinear thermodynamic multiphase field models;

[0046] Based on the representative volume unit to describe the macroscopic scale effect, the homogenization method is used to calculate the corresponding macroscopic thermophysical parameters;

[0047] Realize the mapping interaction from small-scale micro data to large-scale macro data.

[0048] Furthermore, the free energy density function of the multiphase system in the welding process is described based on the conservative phase field and gradient flow theory;

[0049] Consider the nonlinear effects of phase field distribution and solute field distribution on macroscopic solid-liquid phase density, specific heat capacity and other thermophysical parameters;

[0050] A unified diffusion interface model of macroscopic lattice Boltzmann multiphase flow in laser welding, taking into account the microscopic phase / mass distribution, is constructed using the phase field method and the lattice Boltzmann method. The phase field method is used to track the gas-liquid free surface, while the lattice Boltzmann method is used to solve the temperature field and flow field equations.

[0051] Furthermore, the substitutional solution model is used to obtain the thermodynamic driving forces of various phases at the microscopic scale in real time:

[0052] The lattice Boltzmann method is used to obtain the dissipative resistance to dendrite growth induced by macroscopic melt flow;

[0053] Combined with the non-isothermal extrapolation method, a multiphase field model of microstructure evolution of laser welding with nonlinear thermodynamic coupling under the influence of macroscopic heat / flux distribution is constructed.

[0054] Another object of the present invention is to provide a laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling system comprising:

[0055] The derivation module is used to derive a mathematical model describing the evolution of the microscopic phase field driven by the macroscopic temperature field and flow field, based on the principles of nonlinear thermodynamics and fluid dynamics, taking into account the influence of the macroscopic temperature field and flow field on the phase field;

[0056] Establish a module to consider the influence of fluid flow on solute transport based on the momentum conservation equation and establish a mathematical model to describe the evolution of macroscopic flow field and microscopic phase solute field;

[0057] Extraction module, used to extract spatiotemporal distribution data of key parameters such as macro-scale temperature field and flow field;

[0058] Description module, used to describe the free energy density function of the multiphase system in the welding process based on the conservative phase field and gradient flow theory;

[0059] Acquisition module, used to obtain the thermodynamic driving forces of various phases at the microscale in real time based on the substitutional solution model;

[0060] The construction module is used to determine the real-time sequential solution method of the model based on the macro model and micro simulation established above, combined with the physical scale relationship of the macro-micro model time step, and construct a macro-micro bidirectional coupling model of laser welding considering macro heat / flow and micro phase / quality.

[0061] Another object of the present invention is to provide a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method.

[0062] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to execute the steps of the laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method.

[0063] Another object of the present invention is to provide an information data processing terminal, which is used to implement the laser welding macro-micro multi-physical field cross-scale bidirectional coupling modeling system.

[0064] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0065] First, the present invention establishes a bidirectional coupling mechanism of macroscopic temperature field / flow field-microscopic phase field / solute field, proposes a bidirectional collaborative interaction method of cross-scale data, and thus proposes a macro-micro multi-physics field / cross-scale bidirectional coupling modeling method for laser welding, which realizes accurate simulation of macro-micro forming in the laser welding process.

[0066] This project adopts the diffusion interface theory, considers the macroscopic heat flow information to revise the microscopic phase field and solute field evolution equations, considers the microscopic phase and mass information to revise the macroscopic temperature field and flow field evolution equations, and innovatively constructs a macroscopic heat flow-microscopic phase and mass multi-physics field bidirectional coupling model to realize macroscopic and microscopic bidirectional coupling calculations within the same computational domain.

[0067] This model can overcome the limitations of traditional sharp interface coupling and provide a theoretical model basis for the accurate prediction of macroscopic formation and microstructural evolution in the laser welding process.

[0068] Second, the present invention solves the technical problems of the prior art and achieves significant technical progress in industrial applications.

[0069] 1. Existing technical problems solved

[0070] 1. Insufficient simulation accuracy

[0071] Current macro-micro multi-physics modeling methods for laser welding rely primarily on the "one-way input" of macroscopic information into the microscopic simulation. This approach, using macroscopic heat flow information as input, unidirectionally drives the evolution of the microscopic phase and solute fields. This approach ignores the complex interactions between the macroscopic temperature and flow fields and the microscopic phase and solute fields, resulting in significant deviations between the simulation results and the actual welding process, failing to accurately reflect the true physical phenomena.

[0072] 2. Process optimization is limited

[0073] The lack of a modeling method for bidirectional macro-micro coupling limits existing technologies in optimizing laser welding process parameters. Simulations cannot accurately predict the combined impact of different process parameter combinations on welding quality and energy consumption, resulting in process optimization relying on extensive experimentation and experience, which is inefficient and costly.

[0074] 3. Difficulty in equipment design and control

[0075] Existing one-way modeling methods struggle to provide accurate data support for the design and real-time control of laser welding equipment. This lack of a comprehensive understanding of the dynamic interaction between macroscopic and microscopic physical fields makes it difficult to achieve optimal performance in actual operation, impacting the stability and consistency of the welding process.

[0076] 4. Extended R&D cycle

[0077] Due to the limitations of simulation models, the development of new processes and materials requires extensive experimental verification, increasing R&D costs and cycles. The lack of high-precision, bidirectionally coupled modeling tools hinders the rapid iteration and application of new technologies, reducing the efficiency of industrial innovation.

[0078] 5. Not adaptable to changes in complex working conditions

[0079] In actual production, laser welding processes often face complex operating conditions, such as dynamic changes in welding speed, laser power, and environmental conditions. Existing one-way modeling methods struggle to adapt to and accurately simulate these changes in real time, resulting in a lack of effective early warning and adjustment methods for emergencies, impacting production stability and product consistency.

[0080] 6. Low resource utilization efficiency

[0081] Due to inaccurate simulations, existing technologies waste energy and materials. For example, the inability to accurately predict and control heat input leads to excessive energy consumption or excessive material melting, reducing resource efficiency in the overall production process and increasing operating costs.

[0082] Existing macro-micro multi-physics modeling methods for laser welding have significant shortcomings in simulation accuracy, process optimization, equipment design and control, R&D efficiency, handling complex working conditions, and resource utilization. These technical issues limit the widespread application of laser welding technology in high-precision, high-efficiency, and high-reliability applications. They urgently need to be addressed by establishing a more comprehensive and accurate macro-micro bidirectional coupling model to improve overall production efficiency and economic benefits.

[0083] 2. Significant Technological Advances

[0084] 1. Bidirectional coupling modeling methods and systems significantly improve simulation accuracy:

[0085] The present invention is based on the principles of nonlinear thermodynamics and fluid dynamics, considers the influence of macroscopic temperature field and flow field on phase field, and derives a mathematical model to describe the evolution of microscopic phase field driven by macroscopic temperature field and flow field; based on the momentum conservation equation, considers the influence of fluid flow on solute transport, and establishes a mathematical model to describe the evolution of macroscopic flow field and microscopic phase solute field; considers the influence of microscopic phase field on macroscopic temperature field, and establishes the energy conservation equation under the microscopic phase field distribution-mushy zone solid phase fraction-solid-liquid phase change latent heat mapping model; considers the influence of microscopic phase field and solute distribution on macroscopic flow field equation, and establishes the macroscopic momentum conservation equation driven by the evolution of mushy zone solid phase fraction and solute distribution-mushy zone thermophysical property parameters, thereby establishing a complete multi-physical field bidirectional coupling mechanism at the physical level to achieve precise simulation.

[0086] 2. Effectively support process optimization:

[0087] Based on the above-mentioned bidirectional coupling method for laser welding, the spatiotemporal evolution of the three-dimensional microstructure of the weld under different combinations of process parameters such as laser welding power, welding speed, defocus, and laser beam inclination can be accurately simulated; a welding process range with beautiful weld formation, excellent mechanical properties, and low comprehensive energy consumption can be obtained; thereby reducing the blindness and experimental costs of process optimization.

[0088] 3.Limited reduction in equipment design and control difficulty

[0089] Bidirectional coupling modeling can clarify the evolutionary mechanisms of laser welding's macro- and micro-structures, revealing how laser welding process parameters influence weld quality. This provides precise data support for the design and real-time control of laser welding equipment. A comprehensive understanding of the dynamic interaction between macroscopic and microscopic physical fields effectively supports process parameter control methods for laser welding equipment, optimizing equipment energy consumption and ensuring the stability and consistency of the welding process.

[0090] 4. Shorten the research and development cycle of new laser welding processes

[0091] The bidirectional coupling method and system proposed in the present invention break away from the dependence of traditional modeling methods on equipment process parameters and material thermophysical properties. They can quickly carry out process simulation tests based on the process requirements of new materials, and realize rapid principle exploration of new processes and new materials, thereby greatly improving the R&D speed and accelerating the rapid iteration and promotion and application of new technologies.

[0092] 5. Achieve adaptive adaptation to complex working conditions

[0093] Based on the massive simulation results obtained using the bidirectional coupling method, a knowledge base for laser welding processes can be further constructed, allowing for quantitative analysis of weld quality changes under different laser welding parameters at a mechanistic level. This allows for rapid and accurate prediction of weld formation results as laser welding process parameters change, ensuring quality inspection of the welding process.

[0094] 6. Improve resource utilization efficiency

[0095] Based on accurate simulation results, we can determine the laser welding process parameter range, within which we can further evaluate energy consumption and material loss under different process parameter combinations. By adjusting process parameters, we can optimize energy consumption or save materials, improving resource utilization efficiency and reducing operating costs throughout the production process.

[0096] The proposed method and system for cross-scale, bidirectional coupling modeling of macro- and micro-scale multi-physics fields in laser welding, through innovative bidirectional coupling mechanisms, cross-scale data interaction methods, and simulation models, significantly improves the precise simulation of macroscopic weld formation and microstructural evolution in laser welding. This addresses the shortcomings of existing one-way coupling models in simulation accuracy, process optimization support, and equipment control stability. Furthermore, the proposed method and system are universally applicable to new materials and processes for laser welding, further improving the efficiency of R&D iterations, reducing the market promotion and application cycle of new technologies, and enhancing overall production efficiency and economic benefits.

[0097] Third, as auxiliary evidence for the inventiveness of the claims of the present invention, it is also reflected in the following important aspects:

[0098] (1) The expected benefits and commercial value of the technical solution of the present invention after transformation are:

[0099] This invention significantly improves welding quality and efficiency while reducing production costs by providing a method and system for cross-scale, bidirectional coupling modeling of macro- and micro-scale multi-physics fields in laser welding. Specific expected benefits include: improving the quality and consistency of welded products and reducing scrap rates; optimizing welding process parameters and improving production efficiency; reducing energy consumption and material waste; and enhancing product market competitiveness. The commercial value also includes promoting the application of laser welding technology in aerospace, marine vessels, automotive, and other fields, with broad market application prospects and expected significant economic and social benefits.

[0100] (2) The technical solution of the present invention fills the technical gap in the industry at home and abroad:

[0101] The technical solution of this invention fills a gap in the field of cross-scale, bidirectional coupled modeling of macro- and micro-scale multi-physics fields in laser welding, both domestically and internationally. Conventional one-way simulations typically focus on a single scale or simplified physical field coupling. However, this invention, through cross-scale, bidirectional coupled modeling, can more accurately simulate the macro- and micro-physical phenomena in the welding process, addressing shortcomings of existing technologies in simulation accuracy and efficiency.

[0102] (3) Whether the technical solution of the present invention solves the technical problems that people have been eager to solve but have not been able to solve successfully:

[0103] The technical solution of this invention solves a long-standing technical problem. Traditional welding simulation technology has limitations when dealing with complex multi-physics coupling and cross-scale issues, resulting in significant deviations between simulation results and the actual welding process. This invention, through an innovative multi-physics cross-scale bidirectional coupling modeling method, achieves accurate simulation and prediction of the welding process, resolving this long-standing problem that has plagued the industry.

[0104] (4) Whether the technical solution of the present invention overcomes technical prejudice:

[0105] The technical solution of this invention overcomes, to a certain extent, the conventional wisdom that effective coupled modeling of macro- and microscopic physical fields in welding processes is difficult, constraining much research and technological development. This invention overcomes this technical bias through innovative modeling methods, demonstrating the feasibility and effectiveness of bidirectional, cross-scale coupled multi-physics modeling, providing the industry with a new technical approach and solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0106] Figure 1This is a flow chart of the laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method provided by an embodiment of the present invention.

[0107] Figure 2 This is a structural block diagram of the laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling system provided by an embodiment of the present invention.

[0108] Figure 3 It is a diagram of the macro-micro multi-physics field / cross-scale bidirectional coupling mechanism of laser welding provided by an embodiment of the present invention.

[0109] Figure 4 It is a diagram of an interactive method for mapping macro-scale data to micro-scale data provided by an embodiment of the present invention.

[0110] Figure 5 It is a diagram of an interactive method for mapping micro-scale data to macro-scale data provided by an embodiment of the present invention.

[0111] Figure 6 This is a simulation effect diagram of macro-micro bidirectional coupling of laser welding provided by an embodiment of the present invention;

[0112] Figure 7 This is a simulation result diagram of the macro-micro bidirectional coupling experiment of laser welding provided by an embodiment of the present invention, (a) is the macro-scale molten pool-keyhole simulation effect under macro-micro coupling, and (b) is the micro-scale dendrite growth process under macro-micro coupling. DETAILED DESCRIPTION

[0113] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0114] like Figure 1 As shown, a laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method provided by an embodiment of the present invention includes the following steps:

[0115] S101, based on the principles of nonlinear thermodynamics and fluid dynamics, considering the influence of macroscopic temperature field and flow field on phase field, derive the mathematical model describing the evolution of microscopic phase field driven by macroscopic temperature field and flow field;

[0116] The optimized microscopic phase field governing equation is as follows:

[0117]

[0118] Where τ0 represents the relaxation time, k Cu represents the solute equilibrium distribution coefficient of copper element, u Cu represents the dimensionless concentration of copper element, M Curepresents the interpolation function related to the concentration of copper solute, D 1,Cu represents the diffusion coefficient of copper, D l,Li represents the diffusion coefficient of lithium, k Li represents the solute equilibrium distribution coefficient of lithium, u Li represents the dimensionless concentration of lithium element, represents the anisotropy factor, φ represents the phase field, W0 represents the phase field interface thickness, and represents the interpolation function related to the double-well potential and volume free energy, λ represents the coupling coefficient related to the thermodynamic driving force, Δf(T,t) represents the spatiotemporal distribution data of the temperature field obtained by the macro model, f(u,t) represents the spatiotemporal distribution data of the flow field obtained by the macro model, and t represents time;

[0119] S102, based on the momentum conservation equation, considering the effect of fluid flow on solute transport, establish a mathematical model to describe the evolution of macroscopic flow field and microscopic solute field;

[0120] S103, extracting spatiotemporal distribution data of key parameters such as macro-scale temperature field and flow field;

[0121] S104, describing the free energy density function of multiphase system in welding process based on conservative phase field and gradient flow theory;

[0122] S105, real-time acquisition of thermodynamic driving forces of various phases at the microscale based on substitutional solution model;

[0123] S106, based on the macro model and micro simulation established above, combined with the physical scale relationship of the macro-micro model time step, determine the real-time sequential solution method of the model, and construct a macro-micro bidirectional coupling model of laser welding considering macro heat / flow and micro phase / quality.

[0124] The present invention provides a macro-micro multi-physics field cross-scale bidirectional coupling modeling method for laser welding, which aims to achieve accurate simulation and optimization of the laser welding process by combining physical phenomena at the macro and micro scales. The method is first based on the principles of nonlinear thermodynamics and fluid dynamics, considers the influence of the macro temperature field and flow field on the micro phase field, and derives a mathematical model that describes the evolution of the micro phase field driven by the macro temperature field and flow field. In step 1, the temperature field spatiotemporal distribution data Δf(T, t) and the flow field spatiotemporal distribution data f(u, t) obtained by the macro model are introduced into the description of the phase field evolution through the optimized micro phase field control equation, ensuring that the micro phase change process can accurately reflect the changes in the macro environment.

[0125] In step 2, the method further considers the influence of fluid flow on solute transport based on the momentum conservation equation, establishing a mathematical model that describes the evolution of the macroscopic flow field and the microscopic solute field. This model not only simulates the fluid motion and heat conduction at the macroscale but also accurately describes the diffusion and reaction processes of solutes in the microphase, thereby achieving a comprehensive understanding and prediction of multiphase systems during welding.

[0126] Steps 3 through 5 are performed sequentially. First, the spatiotemporal distribution data of key parameters, such as the macroscale temperature and flow fields, are extracted to ensure accurate and reliable data input for the macromodel. Next, based on the theory of conservative phase field and gradient flow, the free energy density function of the multiphase system during the welding process is described, establishing the thermodynamic foundation of the system. Finally, the substitutional solution model is used to obtain the thermodynamic driving forces of various microscale phases in real time, providing a kinetic basis for phase field evolution. These steps ensure that the microscopic phase transformation process can dynamically respond to changes in the macroscopic environment, enhancing the model's realism and applicability.

[0127] Finally, in step 6, based on the established macroscopic model and microscopic simulation, and incorporating the physical scale relationship between the macro- and microscopic model time steps, a real-time sequential solution method was determined. A macro- and microscopic bidirectional coupling model for laser welding was constructed, accounting for the interaction between macroscopic heat / fluid and microscopic phase / mass. This coupling model, through a bidirectional feedback mechanism, enables information exchange and dynamic adjustment between the macroscopic and microscopic scales, making the simulation of the entire welding process more accurate and efficient. Ultimately, this method not only improves the simulation accuracy of the laser welding process but also provides strong technical support for optimizing welding process parameters, improving welding quality, and reducing energy consumption.

[0128] The laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method of the present invention successfully realizes the comprehensive simulation and control of complex physical phenomena in the laser welding process through systematic steps and scientific mathematical models, significantly improves the understanding and optimization capabilities of the welding process, and has broad application prospects and significant technical advantages.

[0129] The embodiment of the present invention provides a mathematical model that describes the evolution of the macroscopic flow field and the microscopic solute field based on the momentum conservation equation and taking into account the influence of fluid flow on solute transport:

[0130] The optimized microscopic solute field evolution equation is as follows:

[0131]

[0132] Where, α m represents the material phase fraction, ρ m Indicates the material density, C l represents the concentration of liquid solute, C represents the total solute concentration, Dl represents the diffusion coefficient, represents the corrected liquid phase solute concentration, k v is the solute equilibrium distribution coefficient, C s represents the solid phase solute concentration, f l represents the liquid fraction, u represents the velocity, f s represents the solid phase fraction;

[0133] Considering the influence of the microscopic phase field on the macroscopic temperature field, the energy conservation equation is established under the microscopic phase field distribution-mushy region solid phase fraction-solid-liquid phase transition latent heat mapping model;

[0134] The optimized macroscopic temperature field control equation is as follows:

[0135]

[0136] Where, ρ(f s ,c,t) represents the spatial density under different solid fractions, solute concentrations and time steps, h represents the thermal enthalpy, λ T represents the thermal diffusion coefficient, T represents the temperature, and q laser represents the laser heat source, q vap represents evaporative heat dissipation, L represents latent heat of fusion, q rad Indicates radiative heat dissipation.

[0137] The embodiment of the present invention provides a macroscopic momentum conservation equation driven by the evolution of the solid fraction in the mushy zone and the solute distribution-the thermophysical property parameters in the mushy zone, taking into account the influence of the microscopic phase field and the solute distribution on the macroscopic flow field equation.

[0138] The optimized macroscopic momentum conservation equation is as follows:

[0139]

[0140] Where p represents pressure, F s represents surface tension, F b represents gravity, S represents the mushy zone constant, P recoil Indicates steam recoil pressure.

[0141] The embodiments of the present invention provide for extracting spatiotemporal distribution data of key parameters such as macro-scale temperature field and flow field:

[0142] Based on the interlayer interpolation technology of generative adversarial neural networks, a machine learning model is trained to generate double interpolation results from macroscopic heat / flow (mm / ms level) to microscopic temperature gradient-growth rate (um / us level);

[0143] Realize the mapping interaction from macroscopic low temporal and spatial resolution to microscopic high temporal and spatial resolution asynchronous (ms~us) / heterogeneous (mm~um) data;

[0144] Extract the spatiotemporal distribution data of key parameters such as phase field and solute field of microscopic nonlinear thermodynamic multiphase field models;

[0145] Based on the representative volume unit to describe the macroscopic scale effect, the homogenization method is used to calculate the corresponding macroscopic thermophysical parameters;

[0146] Realize the mapping interaction from small-scale micro data to large-scale macro data.

[0147] The embodiment of the present invention provides a multiphase system free energy density function for describing the welding process based on the conservative phase field and gradient flow theory;

[0148] Consider the nonlinear effects of phase field distribution and solute field distribution on macroscopic solid-liquid phase density, specific heat capacity and other thermophysical parameters;

[0149] A unified diffusion interface model of macroscopic lattice Boltzmann multiphase flow in laser welding, taking into account the microscopic phase / mass distribution, is constructed using the phase field method and the lattice Boltzmann method. The phase field method is used to track the gas-liquid free surface, while the lattice Boltzmann method is used to solve the temperature field and flow field equations.

[0150] The embodiment of the present invention provides a substitutional solution model based on which the thermodynamic driving forces of various phases at the microscale are obtained in real time:

[0151] The lattice Boltzmann method is used to obtain the dissipative resistance to dendrite growth induced by macroscopic melt flow;

[0152] Combined with the non-isothermal extrapolation method, a multiphase field model of microstructure evolution of laser welding with nonlinear thermodynamic coupling under the influence of macroscopic heat / flux distribution is constructed.

[0153] like Figure 2 As shown, an embodiment of the present invention provides a laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling system comprising:

[0154] The derivation module is used to derive a mathematical model describing the evolution of the microscopic phase field driven by the macroscopic temperature field and flow field, based on the principles of nonlinear thermodynamics and fluid dynamics, taking into account the influence of the macroscopic temperature field and flow field on the phase field;

[0155] Establish a module to consider the influence of fluid flow on solute transport based on the momentum conservation equation and establish a mathematical model to describe the evolution of macroscopic flow field and microscopic phase solute field;

[0156] Extraction module, used to extract spatiotemporal distribution data of key parameters such as macro-scale temperature field and flow field;

[0157] Description module, used to describe the free energy density function of the multiphase system in the welding process based on the conservative phase field and gradient flow theory;

[0158] Acquisition module, used to obtain the thermodynamic driving forces of various phases at the microscale in real time based on the substitutional solution model;

[0159] The construction module is used to determine the real-time sequential solution method of the model based on the macro model and micro simulation established above, combined with the physical scale relationship of the macro-micro model time step, and construct a macro-micro bidirectional coupling model of laser welding considering macro heat / flow and micro phase / quality.

[0160] Another object of the present invention is to provide a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method.

[0161] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to execute the steps of the laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method.

[0162] Another object of the present invention is to provide an information data processing terminal, which is used to implement the laser welding macro-micro multi-physical field cross-scale bidirectional coupling modeling system.

[0163] The present invention is specifically implemented:

[0164] The first aspect of the present invention establishes a bidirectional coupling mechanism of macroscopic temperature field / flow field-microscopic phase field / solute field, such as Figure 3 As shown, the main contents include:

[0165] Based on the principles of nonlinear thermodynamics and fluid dynamics, the influence of macroscopic temperature field and flow field on phase field is considered, and a mathematical model describing the evolution of microscopic phase field driven by macroscopic temperature field and flow field is derived.

[0166] The optimized microscopic phase field governing equation is as follows:

[0167]

[0168] Where τ0 represents the relaxation time, k Cu represents the solute equilibrium distribution coefficient of copper element, u Cu represents the dimensionless concentration of copper element, M Cu represents the interpolation function related to the concentration of copper solute, D l,Cu represents the diffusion coefficient of copper, D l,Li represents the diffusion coefficient of lithium, k Li represents the solute equilibrium distribution coefficient of lithium, uLi represents the dimensionless concentration of lithium element, represents the anisotropy factor, φ represents the phase field, W0 represents the phase field interface thickness, and represents the interpolation function related to the double-well potential and volume free energy, λ represents the coupling coefficient related to the thermodynamic driving force, Δf(T,t) represents the spatiotemporal distribution data of the temperature field obtained by the macro model, f(u,t) represents the spatiotemporal distribution data of the flow field obtained by the macro model, and t represents time;

[0169] The embodiment of the present invention provides a mathematical model that describes the evolution of the macroscopic flow field and the microscopic solute field based on the momentum conservation equation and taking into account the influence of fluid flow on solute transport;

[0170] The optimized microscopic solute field evolution equation is as follows:

[0171]

[0172] Where, α m represents the material phase fraction, ρ m Indicates the material density, C l represents the concentration of liquid solute, C represents the total solute concentration, D l represents the diffusion coefficient, represents the corrected liquid phase solute concentration, k v is the solute equilibrium distribution coefficient, C s represents the solid phase solute concentration, f l represents the liquid fraction, u represents the velocity, f s represents the solid phase fraction;

[0173] The embodiment of the present invention provides an energy conservation equation that considers the influence of the microscopic phase field on the macroscopic temperature field and establishes a mapping model that considers the microscopic phase field distribution, the solid phase fraction in the mushy zone, and the latent heat of solid-liquid phase change.

[0174] The optimized macroscopic temperature field control equation is as follows:

[0175]

[0176] Where, ρ(f s ,c,t) represents the spatial density under different solid fractions, solute concentrations and time steps, h represents the thermal enthalpy, λ T represents the thermal diffusion coefficient, T represents the temperature, and q laser represents the laser heat source, q vap represents evaporative heat dissipation, L represents latent heat of fusion, q rad Indicates radiative heat dissipation.

[0177] The embodiment of the present invention provides a macroscopic momentum conservation equation driven by the evolution of the solid fraction in the mushy zone and the solute distribution-the thermophysical property parameters in the mushy zone, taking into account the influence of the microscopic phase field and the solute distribution on the macroscopic flow field equation.

[0178] The optimized macroscopic momentum conservation equation is as follows:

[0179]

[0180] Where p represents pressure, F s represents surface tension, F b represents gravity, S represents the mushy zone constant, P recoil Indicates steam recoil pressure.

[0181] The second aspect of the present invention proposes a method for cross-scale bidirectional collaborative interaction of macro / micro spatiotemporal asynchronous / heterogeneous data, including:

[0182] Extract spatiotemporal distribution data of key parameters such as macro-scale temperature and flow fields;

[0183] The interlayer interpolation technology based on generative adversarial neural networks provided in the embodiments of the present invention trains a machine learning model to generate dual interpolation results from macroscopic heat / flow (mm / ms level) to microscopic temperature gradient-growth rate (um / us level);

[0184] The embodiment of the present invention provides a method for realizing the mapping interaction of macroscopic low spatiotemporal resolution to microscopic high spatiotemporal resolution asynchronous (ms~us) / heterogeneous (mm~um) data, such as Figure 4 As shown;

[0185] Extract the spatiotemporal distribution data of key parameters such as phase field and solute field of microscopic nonlinear thermodynamic multiphase field models;

[0186] The embodiment of the present invention provides a method for describing macroscopic scale effects based on representative volume units and calculating corresponding macroscopic thermophysical parameters using a homogenization method;

[0187] The embodiment of the present invention provides an implementation for constructing a mapping interaction from small-scale microscopic data to large-scale macroscopic data, such as Figure 5 shown.

[0188] The third aspect of the present invention constructs a macro-micro bidirectional coupling model of laser welding that considers heat / flux distribution and phase / mass distribution, including:

[0189] Based on the conservative phase field and gradient flow theory, the free energy density function of the multiphase system in the welding process is described;

[0190] The embodiments of the present invention provide a method for considering the nonlinear effects of phase field distribution and solute field distribution on macroscopic solid-liquid phase density, specific heat capacity and other thermophysical parameters;

[0191] The present invention provides a method for constructing a macroscopic lattice Boltzmann multiphase flow unified diffusion interface model for laser welding that considers microscopic phase / mass distribution using the phase field method and the lattice Boltzmann method. The phase field method is used to track the gas-liquid free surface, while the lattice Boltzmann method is used to solve the temperature field and flow field equations.

[0192] Obtain the thermodynamic driving forces of various phases at the microscale in real time based on the substitutional solution model;

[0193] The embodiment of the present invention provides a method for obtaining the dendrite growth dissipation resistance induced by macroscopic melt flow using a lattice Boltzmann method;

[0194] The embodiment of the present invention provides a non-isothermal extrapolation method to construct a multiphase field model of microstructure evolution of laser welding with nonlinear thermodynamic coupling under the influence of macroscopic heat / flow distribution;

[0195] Based on the macroscopic model and microscopic simulation established above, combined with the physical scale relationship between the time steps of the macroscopic and microscopic models, the real-time sequential solution method of the model is determined, and a macroscopic and microscopic bidirectional coupling model of laser welding considering macroscopic heat / flow and microscopic phase / quality is constructed.

[0196] Example 1: Periodic Fluctuation Behavior of Titanium Alloy Keyhole

[0197] 1. Background and Requirements

[0198] Titanium alloys, with their high specific strength and excellent corrosion resistance, are suitable for applications such as aerospace and automotive, where weight and strength are critical. Welding is a key manufacturing process. Laser welding, an advanced optomechanical and electrical welding technology, is widely used in the manufacture of titanium alloy components. However, keyhole fluctuation behavior directly affects the stability of the welding process and warrants urgent research.

[0199] 2. Material properties

[0200] Based on the bidirectional coupling method and system of the present invention, a numerical simulation experiment of titanium alloy laser welding was carried out, and the material parameters are as follows:

[0201] Density 4378.48 kg / m 3 , laser absorptivity 0.0158 mPa·s, solidus temperature 1878 K, liquidus temperature 2023 K, surface tension 1.588 N / m, Fresnel absorption coefficient 0.2, latent heat of fusion 3×10 5 J / kg, latent heat of vaporization 0.65×10 -7 J / kg.

[0202] 3. Experimental simulation effect

[0203] The simulation experiment was carried out with the welding parameters of laser power 200W, welding speed 800mm / s and 0 defocus. The simulation results are as follows Figure 6 As shown in (a), the integrated simulation of the molten pool and keyhole is realized.

[0204] 4. Conclusion and application prospects

[0205] like Figure 6 (b) shows that the embodiment of the present invention has made statistics on the opening length of the keyhole section at Z = -24 microns, and the statistical results are as follows: Figure 6 As shown in (c), it can be seen from the figure that the keyhole opening length has obvious periodic fluctuation behavior, which provides effective support for the later research on the stability mechanism of laser welding keyhole and the control of process parameters.

[0206] Example 2: Numerical simulation of macro-micro bidirectional coupling of aluminum alloy

[0207] 1. Background and Requirements

[0208] Aluminum alloy laser welding is an advanced manufacturing technology that uses laser energy to melt and bond aluminum alloy materials. Due to the lightweight, high-strength, and excellent thermal conductivity of aluminum alloys, the application of laser welding technology is particularly important for this material. The microstructure of aluminum alloy welds determines their mechanical properties, so we continue to conduct integrated macro-micro simulations to predict weld microstructures.

[0209] 2. Material properties

[0210] Based on the above model, the aluminum alloy laser welding process was numerically simulated, and its thermophysical parameters were as follows: liquid metal density 2350 kg m -3 Solid metal density 2670kg m -3 , viscosity 1.3×10 -3 kg m -1 s -1 、Liquid specific heat 1170J kg -1 K -1 、Solid relative heat 1040J kg -1 K -1 , liquid phase thermal conductivity 90W m -1 K -1 , solid phase thermal conductivity 150W m -1 K -1 , liquidus temperature 913.15K, solidus temperature 813.15K, heat transfer coefficient 20W m -2 K -1 Surface tension 0.907 N m -1 , latent heat of fusion 3.62×105J kg -1 , latent heat of vaporization 1.08×107J kg -1, surface tension gradient -0.271×10-3N m -1 K -1 .

[0211] 3. Experimental simulation effect

[0212] The experimental simulation results are as follows Figure 7 shown. Figure 7 (a) Macro-scale melt pool-keyhole simulation under macro-micro coupling. Thanks to the diffusion interface method proposed in this paper, accurate tracking of the keyhole interface is achieved. Figure 7 (b) Microscale dendrite growth simulation under macro-micro coupling, showing the dendrite growth process under the influence of macroscopic temperature field and flow field.

[0213] 4. Conclusion and Application Prospects

[0214] This example demonstrates that the proposed macro-micro bidirectional coupling method and system for laser welding is feasible for achieving integrated macro-micro synchronous simulation. More accurate numerical simulation results can provide strong theoretical support for the control of laser welding process parameters.

[0215] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware portion can be implemented using dedicated logic; the software portion can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. Those skilled in the art will appreciate that the above-mentioned devices and methods can be implemented using computer-executable instructions and / or contained in processor control code, for example, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, or can be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0216] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method, characterized by: The following steps are involved: Step 1: Based on the principles of nonlinear thermodynamics and fluid dynamics, considering the influence of the macroscopic temperature field and flow field on the phase field, a mathematical model describing the evolution of the microscopic phase field driven by the macroscopic temperature field and flow field is derived; The optimized microscopic phase field governing equation is as follows: Where τ0 represents the relaxation time, k Cu represents the solute equilibrium distribution coefficient of copper element, u Cu represents the dimensionless concentration of copper element, M Cu represents the interpolation function related to the concentration of copper solute, D 1，Cu represents the diffusion coefficient of copper, D l，Li represents the diffusion coefficient of lithium, k Li represents the solute equilibrium distribution coefficient of lithium, u Li represents the dimensionless concentration of lithium element, represents the anisotropy factor, φ represents the phase field, W0 represents the phase field interface thickness, and represents the interpolation function related to the double-well potential and volume free energy, λ represents the coupling coefficient related to the thermodynamic driving force, Δf(T, t) represents the spatiotemporal distribution data of the temperature field obtained by the macro model, f(u, t) represents the spatiotemporal distribution data of the flow field obtained by the macro model, and t represents time; Step 2: Based on the momentum conservation equation, considering the effect of fluid flow on solute transport, a mathematical model is established to describe the evolution of the macroscopic flow field and microscopic solute field; Step 3: Extract the spatiotemporal distribution data of key parameters such as macro-scale temperature field and flow field; Step 4: Describe the free energy density function of the multiphase system in the welding process based on the conservative phase field and gradient flow theory; Step 5, based on Substitutional so lution model to obtain the thermodynamic driving force of various phases at the microscale in real time; Step 6: Based on the macroscopic model and microscopic simulation established above, combined with the physical scale relationship between the macroscopic and microscopic model time steps, determine the real-time sequential solution method of the model, and construct a macroscopic and microscopic bidirectional coupling model of laser welding that considers macroscopic heat / flow and microscopic phase / quality.

2. The laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method according to claim 1, characterized in that: Based on the momentum conservation equation, the influence of fluid flow on solute transport is considered, and a mathematical model describing the evolution of the macroscopic flow field and the microscopic solute field is established: The optimized microscopic solute field evolution equation is as follows: Where, α m represents the material phase fraction, ρ m Indicates the material density, C l represents the concentration of liquid solute, C represents the total solute concentration, D l represents the diffusion coefficient, represents the corrected liquid phase solute concentration, k v is the solute equilibrium distribution coefficient, C s represents the solid phase solute concentration, f l represents the liquid fraction, u represents the velocity, f s represents the solid phase fraction; Considering the influence of the microscopic phase field on the macroscopic temperature field, the energy conservation equation is established under the microscopic phase field distribution-mushy region solid phase fraction-solid-liquid phase transition latent heat mapping model; The optimized macroscopic temperature field control equation is as follows: Where, ρ(f s , c, t) represents the spatial density under different solid fractions, solute concentrations and time steps, h represents the thermal enthalpy, λ T represents the thermal diffusion coefficient, T represents the temperature, and q laser represents the laser heat source, q vap represents evaporative heat dissipation, L represents latent heat of fusion, q rad Indicates radiative heat dissipation.

3. The laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method according to claim 1, characterized in that: Considering the influence of microscopic phase field and solute distribution on the macroscopic flow field equation, a macroscopic momentum conservation equation driven by the evolution of the solid fraction and solute distribution in the mushy zone and the thermophysical parameters in the mushy zone is established. The optimized macroscopic momentum conservation equation is as follows: Where p represents pressure, F s represents surface tension, F b represents gravity, S represents the mushy zone constant, P recoil Indicates steam recoil pressure.

4. The laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method according to claim 1, characterized in that: The temporal and spatial distribution data of key parameters such as macro-scale temperature field and flow field are extracted: Based on the interlayer interpolation technology of generative adversarial neural networks, a machine learning model is trained to generate double interpolation results from macroscopic heat / flow (mm / ms level) to microscopic temperature gradient-growth rate (um / us level); Realize the mapping interaction from macroscopic low temporal and spatial resolution to microscopic high temporal and spatial resolution asynchronous (ms~us) / heterogeneous (mm~um) data; Extract the spatiotemporal distribution data of key parameters such as phase field and solute field of microscopic nonlinear thermodynamic multiphase field models; Based on the representative volume unit to describe the macroscopic scale effect, the homogenization method is used to calculate the corresponding macroscopic thermophysical parameters; Realize the mapping interaction from small-scale micro data to large-scale macro data.

5. The laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method according to claim 1, characterized in that: The free energy density function of the multiphase system in the welding process is described based on the conservative phase field and gradient flow theory; Consider the nonlinear effects of phase field distribution and solute field distribution on macroscopic solid-liquid phase density, specific heat capacity and other thermophysical parameters; The phase field method and lattice Boltzmann method are used to construct a macroscopic lattice Boltzmann multiphase flow unified diffusion interface model for laser welding considering the microscopic phase / mass distribution; among them, the phase field method is used to track the gas-liquid free surface, and the lattice Boltzmann method is used to solve the temperature field and flow field equations.

6. The laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method according to claim 1, characterized in that: The thermodynamic driving force of various phases at the microscale is obtained in real time based on the Substitutional Solution model: The lattice Boltzmann method is used to obtain the dissipative resistance to dendrite growth induced by macroscopic melt flow; Combined with the non-isothermal extrapolation method, a multiphase field model of microstructure evolution of laser welding with nonlinear thermodynamic coupling under the influence of macroscopic heat / flux distribution is constructed.

7. A laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling system implementing the laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method according to any one of claims 1 to 6, characterized in that: The laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling system includes: The derivation module is used to derive a mathematical model describing the evolution of the microscopic phase field driven by the macroscopic temperature field and flow field, based on the principles of nonlinear thermodynamics and fluid dynamics, taking into account the influence of the macroscopic temperature field and flow field on the phase field; Establish a module to consider the influence of fluid flow on solute transport based on the momentum conservation equation and establish a mathematical model to describe the evolution of macroscopic flow field and microscopic phase solute field; Extraction module, used to extract spatiotemporal distribution data of key parameters such as macro-scale temperature field and flow field; Description module, used to describe the free energy density function of the multiphase system in the welding process based on the conservative phase field and gradient flow theory; Acquisition module, used to obtain the thermodynamic driving forces of various phases at the microscale in real time based on the substitutional solution model; The construction module is used to determine the real-time sequential solution method of the model based on the macro model and micro simulation established above, combined with the physical scale relationship of the macro-micro model time step, and construct a macro-micro bidirectional coupling model of laser welding considering macro heat / flow and micro phase / quality.

8. A computer device, characterized in that: The computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method as described in any one of claims 1 to 6.

9. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the laser welding macro-micro multi-physics field cross-scale bidirectional coupling modeling method according to any one of claims 1 to 6.

10. An information data processing terminal, characterized in that: The information data processing terminal is used to implement the laser welding macro-micro multi-physical field cross-scale bidirectional coupling modeling system as described in claim 7.

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