A laser forging multi-physical field integrated numerical simulation method and system

Abstract

The application discloses a kind of laser fusion forging multi-physical field integrated numerical simulation method and system, belong to additive manufacturing technical field, numerical simulation method includes: establishing three-dimensional geometric calculation domain;Based on calculation domain, through the introduction of mass source term in mass conservation equation, the coaxial powder feeding laser cladding process is simulated;Based on mass source term, solve phase fraction field distribution, and then determine metal and gas interface;Based on phase fraction field, determine the temperature field distribution of calculation domain;Based on phase fraction field and temperature field, the material properties of each region of calculation domain are dynamically updated;Under the constraint of updated material properties, the flow field of liquid metal is calculated based on fluid momentum conservation equation;Based on phase fraction field and temperature field, solve solid momentum conservation equation, determine the stress field of solid region.The application establishes a unified multi-physical field solving framework, avoids the problem of heat-flow and heat-force model fragmentation in traditional method, effectively improves the integrity and accuracy of defect prediction.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, and specifically relates to a multi-physics integrated numerical simulation method and system for laser melting and forging. Background Technology

[0002] Laser melting and forging is an advanced manufacturing process that combines laser additive manufacturing with localized plastic deformation technology. For example... Figure 1 As shown, this process simultaneously achieves material deposition and performance enhancement through the synergistic effect of two lasers: a pre-laser cladding laser melts and deposits the material, while a subsequent pulsed laser acts on the solidified region, inducing localized plastic deformation, thereby reducing porosity and residual stress, and improving forming quality and mechanical properties. With the increasing demands for reliability and extended service life repair of key metal components in high-end manufacturing, traditional welding and thermal spraying processes are insufficient in ensuring repair quality and performance stability. Laser forging, by simultaneously achieving material reconstruction and performance enhancement, is suitable for high-quality repair of high-value-added components such as aero-engines and energy pipelines, effectively extending service life, reducing replacement costs, and demonstrating significant engineering application value.

[0003] Laser cladding and laser shock annealing involve the coupling and dynamic interaction of multiple physical mechanisms, including heat conduction, molten pool flow, residual stress accumulation and release, and microstructure evolution, requiring numerical simulation for analysis. However, existing numerical simulation methods for laser cladding and laser shock annealing processes have shortcomings. Specifically, simulations of laser cladding and laser shock annealing are typically performed independently using different software, making it difficult to achieve integrated simulation of the thermo-fluid-mechanical multiphysics fields within a single numerical framework. In particular, cladding simulations often employ Computational Fluid Dynamics (CFD) software, focusing on the flow field (e.g., publication CN108193204B) and the melting and solidification process, neglecting the influence of the solid stress field. Shock annealing simulations, on the other hand, rely on the Finite Element Method (FEM) software, focusing on stress response analysis but ignoring the dynamic flow behavior of the molten pool. This separation in modeling and solution methods leads to fragmented simulations of the multiphysics fields in the overall laser cladding and annealing process, making it difficult to fully represent the true physical processes. Therefore, there is an urgent need to develop a new integrated numerical simulation method and system for laser melting and forging using multiple physics fields. Summary of the Invention

[0004] To address the above problems, this invention discloses a multiphysics-integrated numerical simulation method for laser melting and forging, comprising:

[0005] Establish a three-dimensional geometric computational domain;

[0006] Based on the computational domain, the coaxial powder feeding laser cladding process is simulated by introducing a mass source term into the mass conservation equation;

[0007] Based on the mass source term, the phase fraction field distribution is solved, and then the metal-gas interface is determined;

[0008] The temperature field distribution in the computational domain is determined based on the phase fractional field.

[0009] Based on the phase fractional field and temperature field, the material properties of each region in the computational domain are dynamically updated;

[0010] Under the updated material property constraints, the flow field of liquid metal is calculated based on the fluid momentum conservation equation;

[0011] Based on the phase fraction field and temperature field, the solid momentum conservation equation is solved to determine the stress field in the solid region.

[0012] Furthermore, the establishment of the three-dimensional geometric computation domain includes the following steps:

[0013] Based on the actual laser melting and forging workpiece and processing area, a three-dimensional geometric calculation domain is established, the calculation domain is meshed, and initial and boundary conditions are set.

[0014] Furthermore, the mass conservation equation is determined by the following formula:

[0015]

[0016] in, ρ For density, t For time, For gradient operators, It is the fluid velocity. It is a source of quality.

[0017] Furthermore, the phase fractional field is determined by the following formula:

[0018]

[0019] in, For quality source rate, It is the phase fraction.

[0020] Furthermore, determining the temperature field distribution of the computational domain based on the phase fractional field includes the following steps:

[0021] Based on the phase fractional field, a laser heat source model is introduced into the energy conservation equation to determine the temperature field distribution in the computational domain and obtain the temperature evolution characteristics of metallic materials under laser irradiation.

[0022] Furthermore, the energy conservation equation is as follows:

[0023]

[0024]

[0025] in, T For temperature, For heat capacity, k Thermal conductivity, S L The latent heat of solid-liquid phase transition, Heat loss due to evaporation, Heat loss due to radiation For laser heat source input, The energy distribution coefficient, A Let P be the absorptivity of the powder to the heat beam, and P be the cladding laser power. x Space for laser heat source x coordinate, y Space for laser heat source y coordinate, The radius of the cladding laser beam is given.

[0026] Furthermore, the fluid momentum conservation equation is determined by the following formula:

[0027]

[0028] in, p For pressure, g It is the acceleration due to gravity. For dynamic viscosity, For buoyancy, For drag force, For surface tension, For Marangoni, This is the recoil pressure.

[0029] Furthermore, the solid momentum conservation equation is determined by the following formula:

[0030]

[0031] in, D It is a displacement vector. For Cauchy stress, The laser impact pressure.

[0032] Furthermore, after solving the solid momentum conservation equation based on the phase fractional field and temperature field to determine the stress field of the solid region, the following steps are included:

[0033] Update the time step and repeat the multiphysics solution in the above steps until the preset simulation termination time step is reached.

[0034] This invention also discloses a multiphysics integrated numerical simulation system for laser melting and forging, comprising:

[0035] Establish a unit to create a three-dimensional geometric computational domain;

[0036] The simulation unit is used to simulate the coaxial powder feeding laser cladding process based on the computational domain and the mass conservation equation;

[0037] The phase fractional field element is used to solve the phase fractional field distribution based on the mass conservation equation, and then determine the metal-gas interface;

[0038] Temperature field element, used to determine the temperature field distribution of the computational domain based on the phase fractional field;

[0039] Material property unit, used to dynamically update the material properties of each region in the computational domain based on phase fraction field and temperature field;

[0040] The flow field element is used to calculate the flow field of liquid metal based on the fluid momentum conservation equation under updated material property constraints.

[0041] Stress field elements are used to solve the solid momentum conservation equation based on the phase fractional field and temperature field to determine the stress field of the solid region.

[0042] Compared with the prior art, the embodiments of the present invention have at least the following advantages:

[0043] (1) This invention establishes a unified multiphysics solution framework, integrating heat conduction, molten pool flow and thermodynamic response modules within the same computing platform, avoiding the problem of separation between heat-flow and thermodynamic models in traditional methods, and effectively improving the integrity and accuracy of defect prediction.

[0044] (2) This invention can provide complete output of key data such as temperature field, flow field and stress / strain field, providing theoretical support for revealing the evolution mechanism of manufacturing defects, the formation of residual stress and the influence of process parameters, and helping to optimize the repair process of complex components such as aero-engines and energy pipelines and implement engineering applications.

[0045] (3) This invention is developed based on the OpenFOAM (Open Field Operation and Manipulation) open source platform. It has good modularity and openness, which makes it easy for users to flexibly modify the control equations, boundary conditions and constitutive relations according to different material systems and laser parameters. It supports subsequent expansion of functions such as microstructure evolution and crack prediction, and meets the needs of various engineering applications for simulation depth and scalability.

[0046] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This diagram illustrates the engineering schematic of the synergistic effect of two lasers in the laser melting and forging process.

[0049] Figure 2 A flowchart of a multiphysics integrated numerical simulation method for laser melting and forging according to an embodiment of the present invention is shown;

[0050] Figure 3 A schematic diagram of a typical scanning path and forging region mesh division according to an embodiment of the present invention is shown;

[0051] Figure 4 A schematic diagram of the energy distribution of a Gaussian heat source according to an embodiment of the present invention is shown. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] This invention aims to overcome the problems of fragmented multiphysics solutions and insufficient computational accuracy in existing laser melting and forging process simulations, and proposes an integrated multiphysics numerical simulation method for laser melting and forging. This method achieves full-process modeling of cladding and impact strengthening within a unified framework, comprehensively describing the multiphysics behavior of the entire laser melting and forging process, and providing reliable technical support for process optimization, quality improvement, and engineering applications.

[0054] like Figure 2 As shown in the figure, the laser melting and forging multiphysics integrated numerical simulation method proposed in this embodiment of the invention includes the following steps:

[0055] Step 1: Geometric Modeling: Establish a 3D geometric computational domain;

[0056] Based on actual laser melting and forging workpieces and processing areas, a three-dimensional geometric calculation domain containing the complete laser scanning path and its surrounding heat-affected zone is established in the OpenFOAM computing platform. This domain is capable of adapting to complex scanning paths and multi-layer, multi-pass forming processes. For example... Figure 3 As shown, the computational domain mainly consists of two parts: the lower metal substrate region and the upper argon-protected region. The computational domain is meshed using OpenFOAM's built-in mesh generation tool: first, a basic hexahedral structure mesh is generated; then, based on the laser scanning trajectory and the expected molten pool location, hierarchical mesh refinement is implemented in key areas, precisely controlling the mesh size of the molten pool and heat-affected zone to the order of 2~10 μm, meeting the accuracy requirements of multiphysics coupled calculations; simultaneously, a progressively coarsening mesh strategy is adopted for the outer regions, significantly reducing computational costs while ensuring accurate implementation of boundary conditions. Subsequently, the initial and boundary conditions required for multiphysics calculations are applied to this computational domain, laying the foundation for subsequent multiphysics numerical solutions. Mesh generation supports a fully three-dimensional unstructured mesh layout and can combine multi-scale local refinement strategies based on regional physical characteristics to implement fine mesh arrangements in key areas (such as the molten pool and heat-affected zone), balancing computational efficiency and accuracy requirements, laying the foundation for high-precision solutions of subsequent thermal-fluid-mechanical multiphysics calculations.

[0057] The initial conditions are set as follows: the initial value of the temperature field is set to the ambient temperature to reflect the thermal state of the workpiece before it is subjected to laser treatment; the initial value of the velocity field is set to a stationary state to meet the physical conditions that the powder has not been fed in and the molten pool has not yet formed; the phase fraction field is set according to the initial state of the workpiece, with the substrate area being a pure solid metal phase (phase fraction of 1) and the gas phase area being a pure gas phase (phase fraction of 0) to ensure a clear interface between the solid substrate and the surrounding gas.

[0058] Boundary condition settings include: applying zero-gradient or adiabatic temperature boundary conditions to the outer surface of the computational domain to simulate natural heat exchange or adiabatic conditions between the system and the outside environment; applying zero-gradient conditions to the pressure field and phase fractional field at the boundaries to ensure the continuous transmission of physical field variables and the consistency of the dynamic evolution of the molten pool; and applying zero-gradient conditions to the displacement field at free boundaries or unconstrained surfaces to realistically simulate the mechanical response of the workpiece during the cladding process. Through the continuous setting of these initial and boundary conditions, a reasonable computational basis can be provided for multiphysics coupling solutions, ensuring the stable and continuous evolution of physical field variables during the simulation process. Boundary conditions include velocity boundaries, temperature boundaries, pressure boundaries, and displacement boundaries.

[0059] This step provides unified spatial and boundary constraints for the entire simulation and is a prerequisite for all subsequent steps.

[0060] Step 2: Coaxial powder feeding modeling: Based on the current... tAt this point, based on the computational domain and initial and boundary conditions established in step 1, the laser cladding process simulation begins. Considering that in coaxial powder-feeding laser cladding, metal powder is coaxially fed into the laser beam through a nozzle and melts and deposits under laser heating, forming a dense cladding layer, the numerical modeling assumes that the mass in the molten pool continuously increases with powder injection. Therefore, a mass source term is introduced into the mass conservation equation to simulate the coaxial powder-feeding laser cladding process. This mass source term can be simplified based on the powder feed rate and the spatial coupling characteristics of the laser beam and the carrier gas flow, thereby improving the realism of the cladding process simulation. The specific expression is:

[0061] (1)

[0062] In the formula, ρ For density, t For time, For gradient operators, It is the fluid velocity. It is a source of quality.

[0063] Step 3: Multiphase Flow Solution: Begin the laser scanning process simulation, scanning the substrate along a predetermined path. Based on the mass source term input in Step 2, the Volume of Fluid (VOF) multiphase flow model is used to solve for the phase fraction field distribution, thereby determining the metal-gas interface. The governing equations of the VOF multiphase flow model are as follows:

[0064] (2)

[0065] In the formula, For quality source rate, For gradient operators, The volume fraction of the metallic phase (i.e., phase fraction) represents its proportion within the mesh cells. When When, it indicates that the current mesh is entirely composed of metallic phase; when At that time, the entire grid is in the gas phase; while when When the metallic and gaseous phases coexist within a mesh cell, the mesh cell in this case is called an "interface cell," which represents the diffuse interface region between the two phases.

[0066] This model describes the occupancy ratio of the metallic and gaseous phases using a phase fraction function, thereby enabling explicit tracking and dynamic evolution simulation of the liquid metal-gas interface. The resulting phase fraction field not only reflects the real-time changes in the molten pool morphology over time but also provides the geometry of the solidification channel interface.

[0067] To improve the accuracy of interface tracking, the initial distribution of the phase fraction function in the VOF model should match the initial state of the molten pool, and the boundary region can be set to a zero gradient form. During the simulation, a smaller time step is preferred, and local mesh refinement is applied to the interface region to enhance the ability to capture the dynamic evolution of the metal / gas interface and ensure the continuity and stability of the interface morphology.

[0068] Step 4, Temperature field solution: Based on the phase fractional field, determine the temperature field distribution in the computational domain;

[0069] Based on the phase fractional field obtained in step 3, a laser heat source model is introduced into the energy conservation equation to solve for the transient temperature distribution (temperature field distribution) in the computational domain, thereby obtaining the temperature evolution characteristics of the metallic material under laser irradiation. The energy conservation equation is expressed as follows:

[0070] (3)

[0071] In the formula, T For temperature, For heat capacity, k Thermal conductivity, S L It is the latent heat of solid-liquid phase transition. Heat loss due to evaporation, Heat loss due to radiation This is the laser heat source input.

[0072] Specifically, such as Figure 4 As shown, the Gaussian surface heat source model can be used for the laser heat source model, and its expression is:

[0073] (4)

[0074] in, Represents the energy distribution coefficient. A The value represents the absorption rate of the powder by the heat beam, and P represents the power of the laser heat source. x Space representing the heat source x Axis coordinates y Space representing the heat source y Axis coordinates (laser beam focus located at) x – y (on a plane) This indicates the radius of the cladding laser beam.

[0075] The temperature field results provide input conditions for updating the material properties in step 5, and also provide thermal load input for solving the stress field in step 7.

[0076] The temperature field calculation mainly considers mechanisms such as heat conduction, thermal radiation, latent heat release during phase change, and laser heat source input to dynamically simulate the temperature field changes during laser scanning. A surface Gaussian heat source model can be used, and the parameters of each heat source model (such as energy absorptivity, energy distribution coefficient, spot radius, and scanning speed) can be reasonably calibrated and optimized based on experimental or literature data.

[0077] Step 5, Update Material Properties: Based on the phase fractional field obtained in Step 3 and the temperature field distribution obtained in Step 4 at the current moment, dynamically adjust and update the material properties of each element in the computational domain. Specifically, this includes key thermophysical and thermomechanical parameters such as density, thermal conductivity, specific heat capacity, viscosity, Young's modulus, Poisson's ratio, and yield strength.

[0078] By setting the thermophysical parameters (such as thermal conductivity, specific heat capacity, density, etc.) and thermomechanical parameters (such as Young's modulus, yield strength, Poisson's ratio, etc.) of the material as temperature-dependent functions, the material's performance evolution during melting, solidification and thermal cycling can be accurately reflected.

[0079] Furthermore, in the solid, liquid, and gas phase regions, the material properties of each phase are predefined as temperature-dependent functions, allowing the property values ​​to dynamically respond to local temperature changes. In grid cells located in phase transition regions (such as the solid-liquid interface region), the proportion of each phase is calculated using the combined information of the phase fraction function and the temperature field, and a weighted average method is used to determine the equivalent material properties of the grid cell, thereby achieving a continuous transition of the solid-liquid-gas three-phase material properties.

[0080] Through this step, the material parameters used in the flow field solution (step 6) and stress field solution (step 7) can reflect the temperature distribution and phase changes of the material in real time during the cladding process, thereby ensuring the accuracy and physical authenticity of the multiphysics coupling simulation.

[0081] Step 6, Flow field solution: Under the updated material property constraints, calculate the flow field of liquid metal based on the fluid momentum conservation equation;

[0082] Solve the fluid momentum conservation equation (incompressible Navier-Stokes equation) to calculate the transient velocity field of the liquid metal in the molten pool, accurately describing its internal flow behavior. The expression for the fluid momentum conservation equation is as follows:

[0083] (5)

[0084] In the formula, p For pressure, g It is the acceleration due to gravity. For dynamic viscosity, For buoyancy, For drag force, For surface tension, For Marangoni, This is the recoil pressure.

[0085] To balance simulation accuracy and computational efficiency, the molten metal in the molten pool can be simplified to an incompressible Newtonian fluid model. Considering the small size of the molten pool and the low Reynolds number during laser scanning, a laminar flow assumption can be further introduced to simplify the calculation of fluid flow within the molten pool, improving simulation efficiency and stability. The driving forces of the molten pool flow are mainly considered as gravity, drag force, surface tension, the Marangoni effect, and recoil pressure.

[0086] Step 7, Stress Field Solution: Combining the phase fraction field calculated in Step 3 and the temperature field calculated in Step 4, and using the laser shock load model, solve the solid momentum conservation equation to calculate the stress and strain field distributions in the solid region (i.e., the solidified metal region). The expression for the solid momentum conservation equation is as follows:

[0087] (6)

[0088] In the formula, D It is a displacement vector. For Cauchy stress, The laser impact pressure.

[0089] Specifically, when solving the momentum conservation equation for solids, all fluid phases (liquid and gaseous phases) are treated as "pseudo-solid" materials. That is, they are artificially endowed with extremely small yield stresses, Poisson's ratios close to 0.5, and Young's moduli. Then, the mechanical parameters of the material at the solid-fluid interface (such as yield strength, Poisson's ratio, and Young's modulus) can be determined based on the phase fraction. and liquid metal volume fraction The calculation shows that:

[0090] (7)

[0091] In the formula, Mechanical parameters representing a pure solid phase; Mechanical parameters representing the liquid phase; The mechanical parameters represent the gas phase. The mechanical parameters of the material are determined by formula (7), and the stress field is solved by formula (6).

[0092] Liquid metal volume fraction It can be determined using a temperature-related error function:

[0093] (8)

[0094] In the formula, Metal curing temperature and liquefaction temperature The arithmetic mean.

[0095] Specifically, in simulating the laser shock strengthening process, the shock wave (shock pressure) is spatially distributed using a Gaussian function, as shown in the following equation:

[0096] (9)

[0097] In the formula, To impact the radius of the laser spot; x for x Axis coordinates y for y Axis coordinates; For time t Distributed laser shock wave pressure, ,in, The peak plasma impact pressure is expressed as:

[0098] (10)

[0099] In the formula, To achieve impact laser power density; This is the ratio of thermal energy to internal energy within the plasma, typically taken as 0.1. Z It is the vibration damping impedance between the material and the confining medium; It is a unit direction vector. This represents the normalized time function, used to describe the change of the laser shock pressure pulse with time t. The laser shock pressure pulse adopts a time-dependent function form such as a triangle, half-sine wave, or exponential decay to accurately reflect the dynamic characteristics of the shock pressure.

[0100] In simulating laser melting and forging, the mechanical response of the solidified region after cooling and solidification needs to be considered comprehensively, taking into account both the temperature field distribution caused by laser scanning and the thermal stress effect caused by thermal load. To accurately describe the mechanical behavior of materials under significant temperature gradients and thermal cycling, it is preferable to introduce an elastoplastic constitutive model or a damage mechanics model to characterize the nonlinear response characteristics of materials under thermo-mechanical coupling conditions.

[0101] Step 8: Proceed to the next time step and repeat the multiphysics solution steps above until the preset termination time step is reached. Specifically, determine the time... t Is it greater than the termination time? t end If yes, then end; if no, then... Repeat the above steps to solve for the multiphysics problem. δt For time steps.

[0102] OpenFOAM, as an open-source finite volume method (FVM) computational platform, possesses multiphysics collaborative modeling and parallel computing capabilities, making it suitable for unified numerical solutions of thermo-fluid-mechanical behavior in laser forging. The integrated numerical simulation method built upon this platform can accurately predict temperature, stress, and flow behavior, providing reliable support for laser forging process optimization and defect control. This improves the repair efficiency and forming quality of key components in aero-engines and energy pipelines, demonstrating significant engineering application value. The numerical simulation method achieves integrated thermo-fluid-mechanical solutions within the same OpenFOAM computational framework, avoiding the fragmentation of multiphysics caused by independently simulating the cladding and impact strengthening processes using different software. This allows for a more accurate and efficient reflection of the physical behavior throughout the entire laser forging process.

[0103] This invention can provide complete output of key data such as temperature field, flow field and stress / strain field, providing theoretical support for revealing the evolution mechanism of manufacturing defects, the formation of residual stress and the influence of process parameters, and helping to optimize the repair process and implement engineering applications of complex components such as aero engines and energy pipelines.

[0104] This invention is developed based on the OpenFOAM open-source platform, which has good modularity and openness. It allows users to flexibly modify the control equations, boundary conditions and constitutive relations according to different material systems and laser parameters. It supports subsequent expansion of functions such as microstructure evolution and crack prediction, and meets the needs of various engineering applications for simulation depth and scalability.

[0105] This invention also discloses a multiphysics integrated numerical simulation system for laser melting and forging, comprising:

[0106] Establish a unit to create a three-dimensional geometric computational domain;

[0107] The simulation unit is used to simulate the coaxial powder feeding laser cladding process based on the computational domain and the mass conservation equation;

[0108] The phase fractional field element is used to solve the phase fractional field distribution based on the mass conservation equation, and then determine the metal-gas interface;

[0109] Temperature field element, used to determine the temperature field distribution of the computational domain based on the phase fractional field;

[0110] Material property unit, used to dynamically update the material properties of each region in the computational domain based on phase fraction field and temperature field;

[0111] The flow field element is used to calculate the flow field of liquid metal based on the fluid momentum conservation equation under updated material property constraints.

[0112] Stress field elements are used to solve the solid momentum conservation equation based on the phase fractional field and temperature field to determine the stress field of the solid region.

[0113] The present invention also proposes an electronic device, including 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-described integrated multiphysics numerical simulation method for laser melting and forging.

[0114] The present invention also proposes a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-described integrated multiphysics numerical simulation method for laser melting and forging.

[0115] The present invention also proposes a computer program product, including computer instructions, which, when executed by a processor, implement the above-described integrated multiphysics numerical simulation method for laser melting and forging.

[0116] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-physics integrated numerical simulation method for laser melting and forging, characterized in that, include: Establish a three-dimensional geometric computational domain; Based on the computational domain, the coaxial powder feeding laser cladding process is simulated by introducing a mass source term into the mass conservation equation; Based on the mass source term, the phase fraction field distribution is solved, and then the metal-gas interface is determined; The temperature field distribution in the computational domain is determined based on the phase fractional field. Based on the phase fractional field and temperature field, the material properties of each region in the computational domain are dynamically updated; Under the updated material property constraints, the flow field of liquid metal is calculated based on the fluid momentum conservation equation; Based on the phase fraction field and temperature field, solve the solid momentum conservation equation to determine the stress field in the solid region; The mass conservation equation is determined by the following formula: in, ρ For density, t For time, For gradient operators, It is the fluid velocity. It is a source of quality; The phase fractional field is determined by the following formula: in, For quality source rate, For phase fractions, It is the fluid velocity. ρ For density, t For time.

2. The laser melting and forging multiphysics integrated numerical simulation method according to claim 1, characterized in that, The establishment of the three-dimensional geometric computation domain includes the following steps: Based on the actual laser melting and forging workpiece and processing area, a three-dimensional geometric calculation domain is established, the calculation domain is meshed, and initial and boundary conditions are set.

3. The laser melting and forging multiphysics integrated numerical simulation method according to claim 1, characterized in that, The determination of the temperature field distribution in the computational domain based on the phase fractional field includes the following steps: Based on the phase fractional field, a laser heat source model is introduced into the energy conservation equation to determine the temperature field distribution in the computational domain and obtain the temperature evolution characteristics of metallic materials under laser irradiation.

4. The laser melting and forging multiphysics integrated numerical simulation method according to claim 3, characterized in that, The energy conservation equation is as follows: in, T For temperature, For heat capacity, k Thermal conductivity, S L The latent heat of solid-liquid phase transition, Heat loss due to evaporation, Heat loss due to radiation For laser heat source input, The energy distribution coefficient, A Let P be the absorptivity of the powder to the heat beam, and P be the cladding laser power. x Space for laser heat source x coordinate, y Space for laser heat source y coordinate, The radius of the cladding laser beam is... It is the fluid velocity. ρ For density, t For time.

5. The laser melting and forging multiphysics integrated numerical simulation method according to claim 1, characterized in that, The fluid momentum conservation equation is determined by the following formula: in, p For pressure, g It is the acceleration due to gravity. For dynamic viscosity, For buoyancy, For drag force, For surface tension, For Marangoni, For recoil pressure, It is the fluid velocity. ρ For density, t For time.

6. The laser melting and forging multiphysics integrated numerical simulation method according to claim 1, characterized in that, The equation for the conservation of momentum in a solid is determined by the following formula: in, D It is a displacement vector. For Cauchy stress, For laser shock pressure, ρ For density, t For time.

7. The laser melting and forging multiphysics integrated numerical simulation method according to claim 1, characterized in that, The process of solving the solid momentum conservation equation based on the phase fractional field and temperature field to determine the stress field of the solid region includes the following steps: Update the time step and repeat the multiphysics solution in the above steps until the preset simulation termination time step is reached.

8. A multiphysics integrated numerical simulation system for laser melting and forging, characterized in that, include: Establish a unit to create a three-dimensional geometric computational domain; The simulation unit is used to simulate the coaxial powder feeding laser cladding process based on the computational domain and the mass conservation equation; The phase fractional field element is used to solve the phase fractional field distribution based on the mass conservation equation, and then determine the metal-gas interface; Temperature field element, used to determine the temperature field distribution of the computational domain based on the phase fractional field; Material property unit, used to dynamically update the material properties of each region in the computational domain based on phase fraction field and temperature field; The flow field element is used to calculate the flow field of liquid metal based on the fluid momentum conservation equation under updated material property constraints. Stress field elements are used to solve the solid momentum conservation equation based on the phase fractional field and temperature field to determine the stress field of the solid region; The mass conservation equation is determined by the following formula: in, ρ For density, t For time, For gradient operators, It is the fluid velocity. It is a source of quality; The phase fractional field is determined by the following formula: in, For quality source rate, For phase fractions, It is the fluid velocity. ρ For density, t For time.

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