Simulation method and system for incompressible viscoelastic plasticity

Abstract

The invention discloses a simulation method and system for incompressible viscoelastic plasticity, which are used for simulating the large deformation behavior of a viscoelastic plastic material, and by decomposing the material attribute into viscosity and elastic plasticity, extracting rotation from the deformation gradient, and using a fixed smooth length, particles may become unconstrained and are irregularly ejected. By utilizing a novel non-iterative algorithm to adjust the smooth length and combining with the artificial viscous force, particle dispersion can be corrected, artifacts caused by serious non-physical oscillation can be avoided, compared with an existing model, the method can provide a rapid and stable solution for various solid and fluid mechanical behaviors, and the method is suitable for large-scale popularization and application. Comprehensive experiments are carried out on various mechanical energy behaviors, and multifunctionality and effectiveness are shown.

Description

Technical Field

[0001] The invention relates to the technical field of adaptive implicit frames, and in particular to a simulation method and system for incompressible viscoelastic plasticity. Background Art

[0002] With the advancement of computer graphics and virtual reality technology, more and more application fields need to create and display realistic virtual worlds, covering many aspects such as games, engineering and movies. The ability of virtual environments to accurately replicate real-world scenes has always been the driving force for the research and development of physically based simulators. In the past few decades, meshless methods have been widely studied and applied. This method can effectively handle complex geometries, large deformations and free surfaces, so it has achieved remarkable achievements in visual effects and physical simulations. Among these methods, the SPH method has become one of the preferred methods in computer graphics simulation, and the SPH scheme for deformable objects has been a continuous area of ​​research. Recent studies have shown that SPH is increasingly effective in simulating viscous fluids, elastoplastic solids and viscoplastic solids.

[0003] Current methods for simulating deformable objects often simulate viscosity by simulating the properties of various fluids and quasi-solids, but this approach has significant limitations because viscous forces only affect the rate of deformation rather than the degree of deformation. On the other hand, from the perspective of viscoelastic schemes, the original plastic flow of simulated materials and their corresponding hardening laws are still limited. Real objects often incorporate viscoelastic-plastic properties, and the lack of any of these aspects will affect the visual effects and simulation results. Summary of the invention

[0004] The object of the present invention is to provide a simulation method and system for incompressible viscoelastic plasticity to overcome the deficiencies of the prior art.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A simulation method for incompressible viscoelastic plasticity comprises the following steps: S1, construct the viscous constitutive model and elastic-plastic constitutive model of the particles respectively; S2, based on the viscous constitutive model of particles, the viscous force of ions is simulated to obtain the viscous force of particles, and the elastic-plastic force is obtained based on the elastic-plastic constitutive model of particles; S3, obtaining the final velocity of the particle based on the obtained particle viscosity and elastic-plastic force, and realizing the simulation of the viscoelastic-plastic properties of the particle.

[0006] Preferably, the incompressible Navier-Stokes equations are used to introduce the forces acting on the particles into the momentum balance equation as follows: (1) In the formula, represents density, Indicates pressure, Represents other external forces, , represent viscous stress and elastic-plastic stress respectively.

[0007] Preferably, based on the viscosity constitutive model of particles, the viscosity force of ions is simulated to obtain the particle viscosity force, and the change rate of the viscosity term on the solution speed is: (2) in, represents the kinematic viscosity of the particle, Represents the velocity of the particle.

[0008] Preferably, a method of implicitly simulating viscous force based on velocity field Laplace operator is adopted.

[0009] Preferably, the elastic-plastic force is obtained based on the elastic-plastic constitutive model of the particle, and the elastic strain and the plastic strain are combined to generate the elastic-plastic strain equation: (5) In the calculation process of the elastic-plastic constitutive model, the elastic-plastic stress rate is derived from the elastic-plastic strain rate to obtain the elastic-plastic stress.

[0010] Preferably, the elastic force is obtained through stress divergence, a correction kernel function and rotation processing are introduced, and the stress tensor is multiplied by the corresponding kernel gradient; a non-iterative particle smoothing length correction is introduced to obtain the elastic-plastic force acting on the particle at a set time.

[0011] A simulation system for incompressible viscoelastic plasticity, including a model building module, a model processing module and a simulation module: Model building module, which builds the viscous constitutive model and elastic-plastic constitutive model of particles; The model processing module simulates the viscosity of ions based on the viscous constitutive model of particles to obtain the particle viscosity, and obtains the elastic-plastic force based on the elastic-plastic constitutive model of particles; The simulation module obtains the final velocity of the particle based on the obtained particle viscosity and elastic-plastic force, and realizes the simulation of the viscoelastic-plastic properties of the particle.

[0012] Preferably, the incompressible Navier-Stokes equations are used to introduce the forces acting on the particles into the momentum balance equation as follows: (1) In the formula, represents density, Indicates pressure, Represents other external forces, , represent viscous stress and elastic-plastic stress respectively.

[0013] Preferably, based on the viscosity constitutive model of particles, the viscosity force of ions is simulated to obtain the particle viscosity force, and the change rate of the viscosity term on the solution speed is: (2) in, represents the kinematic viscosity of the particle, Represents the velocity of the particle.

[0014] Preferably, a method of implicitly simulating viscous force based on velocity field Laplace operator is adopted.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides a simulation method for incompressible viscoelastic plasticity, which is used to simulate the large deformation behavior of viscoelastic plastic materials. By decomposing the material properties into viscosity and elastic plasticity, rotation is extracted from the deformation gradient. Using a fixed smoothing length may cause particles to become unconstrained and irregularly ejected. By adjusting the smoothing length using a novel non-iterative algorithm and combining artificial viscous forces, the present invention can correct particle dispersion and avoid artifacts caused by severe non-physical oscillations. Compared with existing models, the present invention can provide fast and stable solutions for various solid and fluid mechanical behaviors. Comprehensive experiments have been carried out on a variety of mechanical energy behaviors, demonstrating the versatility and effectiveness of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the flow of the simulation method for incompressible viscoelastic-plasticity in an embodiment of the present invention.

[0017] Figure 2 It is a schematic diagram of the overall framework simulated in an embodiment of the present invention.

[0018] Figure 3 Schematic diagram of elastic-plastic material behavior in an embodiment of the present invention.

[0019] Figure 4 Schematic diagram of variable smoothing length in an embodiment of the present invention.

[0020] Figure 5 Schematic diagram for comparing elastic-plastic behaviors in embodiments of the present invention.

[0021] Figure 6 Schematic diagram of average particle change in the number of adjacent elements in an embodiment of the present invention.

[0022] Figure 7 Schematic diagram of rendering effect comparison in an embodiment of the present invention.

[0023] Figure 8 Schematic diagram of different materials falling on an armadillo in an embodiment of the present invention.

[0024] Fig. 9 Schematic diagram comparing cloth simulation results of different methods in an embodiment of the present invention.

[0025] Fig.10 This is a schematic diagram of a dragon falling into a non-Newtonian fluid in an embodiment of the present invention.

[0026] Fig.11 Schematic diagram of data changes during the entire collision process between a rigid body and a shear thickening fluid in an embodiment of the present invention.

[0027] Fig.12 Schematic diagram of disaster simulation of different materials in the same environment in an embodiment of the present invention.

[0028] Fig.13 It is a schematic diagram of soil, iron and rubber rabbit being washed away by water in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] like Figure 1 , Figure 2 As shown, the present invention provides a simulation method for incompressible viscoelastic plasticity, which specifically includes the following steps: S1, construct the viscous constitutive model and elastic-plastic constitutive model of the particles respectively; S2, based on the viscous constitutive model of particles, the viscous force of ions is simulated to obtain the viscous force of particles, and the elastic-plastic force is obtained based on the elastic-plastic constitutive model of particles; S3, obtaining the final velocity of the particle based on the obtained particle viscosity and elastic-plastic force, and realizing the simulation of the viscoelastic-plastic properties of the particle.

[0032] In a specific implementation of the present application, the incompressible Navier-Stokes equation is used to introduce the force acting on the particle into the momentum balance equation, as shown below: (1) In the specific implementation of the present application, the viscoelastic-plastic method is used to construct the viscous constitutive model and the elastoplastic constitutive model of the particles. The viscoelastic-plastic constitutive model is implicitly processed from the perspectives of viscosity and elastoplasticity. In the formula, represents density, Indicates pressure, Represents other external forces, , represent viscous stress and elastic-plastic stress respectively.

[0033] Based on the particle viscosity constitutive model, the viscosity of the ions is simulated to obtain the particle viscosity. The rate of change of the viscosity term on the solution speed is: (2) in, represents the kinematic viscosity of the particle, Represents the velocity of the particle.

[0034] Due to the viscosity It will affect the scattering of the velocity field, so the method of implicitly simulating the viscosity force based on the Laplace operator of the velocity field is adopted.

[0035] The SPH kernel gradient interpolation formula is introduced. In this application, Brookshaw's finite difference method is used to calculate , as shown in formula (3), where Represents the dimension, represents the velocity difference between particles, Indicates distance, For smooth length.

[0036] (3) also, Used to represent particles The viscosity of the dynamic viscosity varies nonlinearly with the strain rate, where the strain rate is given by The Ostwald-Deville nonlinear viscosity model used in this application is as follows: (4) The above represents the classic power law relationship model, where n and m are the power index and consistency index respectively, which can simulate shear thinning (when ) and shear thickening (when hour).

[0037] The elastoplastic force is obtained based on the particle-based elastoplastic constitutive model, and the elastic strain and plastic strain are combined to generate the elastoplastic strain equation: (5) In the calculation process of the elastic-plastic constitutive model, the elastic-plastic stress rate is derived from the elastic-plastic strain rate to obtain the elastic-plastic stress. Since the core gradient lacks first-order consistency and cannot accurately capture the rotation, the mechanical framework used in this application calculates the rotation with reference to the initial position; this application is extended based on the yield criterion: Yield criteria based on elastic strain deviations, such as Figure 3 As shown, the yield criterion condition is: (6) (7) in represents the elastic limit, when the yield condition When the yield condition is met, the material is in an elastic or plastic unloading state and no plastic strain is generated; when the yield condition When is satisfied, the material is in a state of plastic flow, resulting in the following plastic strain increment: (8) In addition, there is a plastic limit , exceeding this limit will cause fracture.

[0038] The plastic strain is expressed as: (9) Incompressibility is achieved by considering density invariance as a source term. However, in cases involving large deformations (such as plastic failure), the number of neighbors of some divergent particles may decrease. This phenomenon not only leads to a decrease in the density of these particles, but also causes erroneous splashing phenomena due to insufficient neighboring particles. Therefore, this application adjusts the smoothing length of the particles based on the principle of maintaining the invariance of particle density, which basically ensures that the total mass of particles in a neighborhood remains unchanged: (10) in Represents the scene dimension, when , ,when , , to keep the mass constant, take the derivative with respect to time and eliminate the common factors After that, the above formula can be further simplified as: (11) Assume that after a time step After that, the smoothed length and density of particle i become and (expressed as: and in and is the initial density and smoothing length of the particle). Then, multiply both sides of the equation by , we can get the above equation (11). During the simulation process, numerical errors may lead to uneven particle distribution, thus causing density changes. Figure 4 As shown, the particle smoothing length in the high-density area remains unchanged, while the smoothing length is increased by the algorithm in the low-density area. The goal of this application is to maintain a stable particle density and ensure smooth changes in the number of particle neighbors by adjusting the particle smoothing length.

[0039] (12) The smoothing length is updated at fixed time step intervals, and the operation is tailored to the specific simulation scenario.

[0040] This application introduces a specific dissipative term into the control equation to more effectively alleviate the non-physical oscillations that do not conform to physical laws in numerical analysis. Therefore, artificial viscosity is introduced into the momentum balance equation (1): (13) in: (14) In the specific implementation of the present application, the method for processing the elastic-plastic model is different from the method for processing the viscous model. The viscous model can directly use the finite difference method, as shown in the above formula (3), which ensures the rotational invariance of the rigid body. The elastic-plastic model generally uses the standard SPH kernel gradient interpolation. In order to achieve first-order consistency in the kernel gradient, it must satisfy: (15) Therefore, the corrected kernel gradient is: (16) (17) In this case, the particles It may be collinear or coplanar, which makes the matrix a singular matrix, which can be solved by Moore-Penrose generalized inverse matrix. The linear Cauchy-Green strain tensor is calculated as follows: (18) Deformation gradient obtained through displacement field , so the solution of the linearized Cauchy–Green strain tensor is extracted directly from the displacement field: (19) Rotation processing: This application extracts the linear Cauchy-Green strain tensor from the displacement field. The rotation capture strategy requires rotating the initial position to the current position, so a kernel gradient correction is performed at the beginning of the simulation. Therefore, the above equation (19) completely relies on SPH interpolation to capture the constant rotation: (20) (twenty one) Elastic stress acquisition method: According to the above formula (5) and formula (19), the elastic strain of the particle can be derived: (twenty two) In this application, the total elastic-plastic stress caused by the particle is calculated using the generalized Hooke's law: (twenty three) In the above equation, represents the shear modulus, represents the bulk modulus. Therefore, the elastic force is obtained through the stress divergence. Due to the introduction of the correction kernel function and the rotation processing, the stress tensor needs to be multiplied by the corresponding kernel gradient. In addition, a non-iterative particle smoothing length correction must be introduced to obtain the elastic-plastic force acting on particle i at time t: (twenty four).

[0041] In the specific implementation of the present application, the above formula (19) and formula (20) are shown in the simulation process and The parameters are linearly dependent, so the above formula (19) can be restated as: (25) However, due to does not show a linear dependence of the two parameters and this aspect must be handled separately in the global elastoplastic stress calculation: (26) in: (27) Similarly, improving particles In time Elastic-plastic force: (28) (29) In the viscous framework, the above equation (3) is modified by combining the non-iterative smoothing length correction method to obtain the equation: (30) Viscous solution showing velocity vectors Therefore, the final implicit velocity acquisition equation is: (31) Based on the conjugate gradient method, the implicit velocity acquisition equation above is transformed to obtain: (32) and Can be transformed into , forming a conjugate gradient iteration formula, and simplifying the original expression into the following form by using the conjugate gradient iteration method: (33) The basis vectors for the conjugate gradient algorithm are , this application uses the conjugate gradient algorithm to ensure that the matrix It is crucial that is symmetric and positive definite. Therefore, and Initially it remains the same during the analysis of the elastic-plastic forces, indicating a uniform distribution of particles. At the same time, the diagonal matrix for the analysis of the viscous forces needs to be modified to: (34) In the specific implementation of the present application, a constant density solver is used to obtain the first updated predicted velocity, and then the pressure term is placed in a scatterless solver and updated to obtain the final velocity .

[0042] The proposed method was integrated into the implicit solver of DFSPH, using the Wendland quintic kernel function. All simulations were parallelized using a 2.50GHz, i7-11700F CPU and rendered using the Blender renderer. Dynamic adjustment of particle smoothing lengths and elastic solutions significantly improved the overall computational speed in terms of time steps under CFL conditions.

[0043] In another embodiment of the present invention, a simulation system for incompressible viscoelastic plasticity is provided, comprising a model building module, a model processing module and a simulation module: Model building module, which builds the viscous constitutive model and elastic-plastic constitutive model of particles; The model processing module simulates the viscosity of ions based on the viscous constitutive model of particles to obtain the particle viscosity, and obtains the elastic-plastic force based on the elastic-plastic constitutive model of particles; The simulation module obtains the final velocity of the particle based on the obtained particle viscosity and elastic-plastic force, and realizes the simulation of the viscoelastic-plastic properties of the particle.

[0044] Preferably, the incompressible Navier-Stokes equations are used to introduce the forces acting on the particles into the momentum balance equation as follows: (1) In the formula, represents density, Indicates pressure, Represents other external forces, , represent viscous stress and elastic-plastic stress respectively.

[0045] Preferably, based on the viscosity constitutive model of particles, the viscosity force of ions is simulated to obtain the particle viscosity force, and the change rate of the viscosity term on the solution speed is: (2) in, represents the kinematic viscosity of the particle, Represents the velocity of the particle.

[0046] In order to verify the effectiveness and superiority of the proposed method, a comparison with a more complex elastic-plastic material was chosen. Because the elastic-plastic material not only undergoes significant deformation, but also requires dynamic constraints on the particles undergoing such deformation, a comparative simulation of the same material was performed using the classic DP elastic-plastic constitutive model proposed by Bui and the viscoelastic-plastic constitutive model proposed by Li.

[0047] Compared with the method of Bu et al.: Figure 5 As shown, the top row adopts the method from Bui's study. This method includes the original dp yield criterion from Bui's study and is enhanced by a simple fracture criterion to simulate such destructive scenarios. By applying an artificial viscosity correction, it can be observed that there are fewer uncontrollable scattered particles and many particles are aggregated into small clusters. However, the extensive iterations and adjustments required for Bui's dp constitutive method result in significantly slower simulation speeds compared to the scheme in this paper.

[0048] Compared with the method of Li et al.: Figure 5 The second row utilizes the viscoelastic-plastic simulation of Li, where the particle dispersion is very severe, resulting in significant artifacts. Figure 5 The third line is a simulation scene using this application, and its rendering scene is as follows Figure 6 As shown. This application uses a non-iterative smoothing length algorithm for correction. Figure 5 In the figure, the number of neighbor particles changes from red to blue. Figure 7The change in the number of neighbor particles shows that the framework in the present application further limits the irregular dispersion of the head particles, thereby enhancing the realism of the simulation scene. The method of the present application has greater advantages in both simulation effect and simulation speed.

[0049] Experiments on the impact of different material properties: Different materials caused different reactions in the silver armadillo. Figure 8 As shown in the first row, the water (or low-viscosity substance) falling from a height quickly bypasses the silver armadillo, but this action has almost no effect on the water that has not touched the armadillo, which continues to fall at a constant acceleration. Finally, at 0.87 seconds, the water flow sweeps over the armadillo's shoulders, leaving very little water on the armadillo's body. When transformed into an elastic-plastic cloth with the same size, as Figure 8 As shown in the second row, the cloth has a Young's modulus of 0.5 MPa, a Poisson's ratio of 0.33, an elastic limit of 0.147, and a plastic limit of 0.642. This material exhibits a certain degree of elastic deformation, and once its elastic limit is exceeded, irreversible plastic deformation occurs. At 1.5 seconds, when the cloth touches the silver armadillo, its edges appear to shrink. At 2 seconds, inertia causes the edges of the cloth to rebound and remain in the deformation stage. After the elastic deformation and recovery stages are over, the cloth gradually stabilizes and no further dynamic changes occur. In addition, the armadillo's ears and hands cause the cloth to tear, resulting in irreversible deformation, which remains in the state at 5 seconds, no matter how much time is calculated.

[0050] When the material is switched to high viscosity honey of the same size, Figure 8 In the third row of scenes, honey is given a dynamic viscosity of 1500 kg / m·s. Figure 4 The 1.5 second mark falls on the head, but Figure 4 The difference in the subsequent simulations is that its high viscosity causes it to break on the armadillo's hand. Then, at 6 seconds, the sticky honey slowly covers the upper body of the silver armadillo and slowly drips. As time goes by, most of the honey falls to the ground and adheres along the armadillo's legs, and some honey still remains on the upper body. In addition, the method of the present application also performs well in simulating non-Newtonian viscous fluids. Fig. 9 As shown, the present application simulates three dragons falling into a mixture of corn starch and water. Fig.10 This reflects the changing process of strain rate and dynamic viscosity in this simulation. It can be observed that when the dragon falls into the mixture, the strain rate suddenly surges. At the same time, the strain rate and dynamic viscosity change exponentially, which corresponds to the dragon suddenly stopping and then gradually sinking into the mixture in the simulation.

[0051] To further verify the wide applicability of the simulation method of this application, the Benjamin data set on water erosion was used, and 3 million particles were used for simulation, but the original water properties were changed to mud flow materials with viscoelastic plastic characteristics. In this study, the mud flow properties were set to Young's modulus 207MPa, Poisson's ratio 0.3, elastic limit 0.001, plastic limit 0.05, and dynamic viscosity 100kg / (m·s). Fig.11 As shown, a clear difference can be seen; on the left there is clear stratification and separation without the strong dispersion typical of water, achieving an effect similar to real-world mudflow erosion.

[0052] Multiple coupling: In simulations involving four different materials, e.g. Fig.12 , Fig.13 As shown in the complex scene in Figure 2, the number of particles involved reaches 145,828, and the calculation time per frame is 1050.695 milliseconds. The simulation also shows strong stability, with a time step ∆t of up to 3 milliseconds under CFL conditions. Fig.11 In the scenario (a), using a viscoelastic-plastic debris flow material with 3 million particles, each frame requires 89658.33 milliseconds to calculate. This shows that the method used in this application can effectively handle complex scenarios with multiple material properties and multi-phase coupling.

[0053] The method in the present application decomposes the mechanical behavior of particle materials into viscosity and elastic-plasticity for implicit solution. In addition to solving the rotational invariance problem through kernel gradient correction, the present application also performs adaptive correction of smoothing length and adjusts artificial viscosity. This method reduces the artifacts of unconstrained particle dispersion in large deformations. Compared with existing methods, the method of the present application has obvious advantages in solving stability and speed. The method of the present application is embedded in the DFSPH solver and can skillfully handle large deformations, composite materials and multiphase coupling.

[0054] Based on the existing Newtonian fluid simulation, this application adopts the basic generalized Maxwell model to incorporate elastic-plastic constitutive behavior and viscosity into a unified framework, which is applicable to all stages. Experimental evidence shows that the method of the present invention can accurately simulate the mechanical behavior of most real materials.

[0055] In the viscoelastic-plastic framework, the proposed method adopts an implicit solution strategy and integrates the conjugate gradient algorithm into the DFSPH solver to speed up the calculation of each frame. In addition, the method significantly increases the time step under CFL conditions, further speeding up the calculation.

[0056] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A simulation method for incompressible viscoelastic plasticity, characterized in that: The following steps are involved: S1, construct the viscous constitutive model and elastic-plastic constitutive model of the particles respectively; S2, based on the viscous constitutive model of particles, the viscous force of ions is simulated to obtain the viscous force of particles, and the elastic-plastic force is obtained based on the elastic-plastic constitutive model of particles; S3, obtaining the final velocity of the particle based on the obtained particle viscosity and elastic-plastic force, and realizing the simulation of the viscoelastic-plastic properties of the particle.

2. A simulation method for incompressible viscoelastic-plasticity according to claim 1, characterized in that: Using the incompressible Navier-Stokes equations, the forces acting on the particle are introduced into the momentum balance equation as follows: （1） In the formula, represents density, Indicates pressure, Represents other external forces, , represent viscous stress and elastic-plastic stress respectively.

3. A simulation method for incompressible viscoelastic-plasticity according to claim 1, characterized in that: Based on the particle viscosity constitutive model, the viscosity of the ions is simulated to obtain the particle viscosity. The rate of change of the viscosity term on the solution speed is: （2） in, represents the kinematic viscosity of the particle, Represents the velocity of the particle.

4. A simulation method for incompressible viscoelastic-plasticity according to claim 1, characterized in that: An implicit method based on the Laplace operator of velocity field is used to simulate the viscosity force.

5. A simulation method for incompressible viscoelastic-plasticity according to claim 1, characterized in that: The elastoplastic force is obtained based on the particle-based elastoplastic constitutive model, and the elastic strain and plastic strain are combined to generate the elastoplastic strain equation: （5） In the calculation process of the elastic-plastic constitutive model, the elastic-plastic stress rate is derived from the elastic-plastic strain rate to obtain the elastic-plastic stress.

6. A simulation method for incompressible viscoelastic-plasticity according to claim 1, characterized in that: The elastic force is obtained through stress divergence, and the correction kernel function and rotation processing are introduced to multiply the stress tensor by the corresponding kernel gradient; the non-iterative particle smoothing length correction is introduced to obtain the elastic-plastic force acting on the particle at a set time.

7. A simulation system for incompressible viscoelastic plasticity, characterized in that: Including model building module, model processing module and simulation module: Model building module, which builds the viscous constitutive model and elastic-plastic constitutive model of particles; The model processing module simulates the viscosity of ions based on the viscous constitutive model of particles to obtain the particle viscosity, and obtains the elastic-plastic force based on the elastic-plastic constitutive model of particles; The simulation module obtains the final velocity of the particle based on the obtained particle viscosity and elastic-plastic force, and realizes the simulation of the viscoelastic-plastic properties of the particle.

8. A simulation system for incompressible viscoelastic-plasticity according to claim 1, characterized in that: Using the incompressible Navier-Stokes equations, the forces acting on the particle are introduced into the momentum balance equation as follows: （1） In the formula, represents density, Indicates pressure, Represents other external forces, , represent viscous stress and elastic-plastic stress respectively.

9. A simulation system for incompressible viscoelastic-plasticity according to claim 1, characterized in that: Based on the particle viscosity constitutive model, the viscosity of the ions is simulated to obtain the particle viscosity. The rate of change of the viscosity term on the solution speed is: （2） in, represents the kinematic viscosity of the particle, Represents the velocity of the particle.

10. A simulation system for incompressible viscoelastic-plasticity according to claim 1, characterized in that: An implicit method based on the Laplace operator of velocity field is used to simulate the viscosity force.

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