Fluid-structure interaction method suitable for explosion and impact dynamics and related equipment

Abstract

The invention discloses a fluid-solid coupling method and device and related equipment. The method comprises the following steps: creating a geometric model of a target object; performing grid division on the geometric model to obtain a discretized grid of the geometric model, and determining a coupling interface; obtaining a physical attribute of the geometric model, and generating a coupling time step length based on the physical attribute; the coupling time step length is adjusted according to the particle spacing of the discretized grid and the size of the finite element, numerical integration is conducted on the smooth particles and the finite element under the constraint of the coupling time step length, integration correction is conducted on the smooth particles, and boundary conditions are applied to the non-failure finite element in the coupling interface; defining a momentum equation; under the constraint of a preset information exchange condition, a momentum equation, a boundary condition and a coupling time step length, physical attributes of smooth particles, finite element nodes and background particles in a coupling interface are coupled and updated, and the processing precision and processing efficiency in the fluid-solid coupling process can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of solid mechanics, and in particular to a fluid-solid coupling method and related equipment. Background Art

[0002] In engineering and science, such as aerospace, marine engineering, biomedical engineering, and energy, simulation of the interaction between fluid and solid domains requires a combination of multiple numerical methods to fully utilize their respective advantages.

[0003] However, existing fluid-structure interaction methods usually rely on the finite element method (FEM) to simulate the solid domain and computational fluid dynamics (CFD) to simulate the fluid domain. This method often requires complex mesh generation and processing techniques when dealing with large deformation and contact problems, and cannot effectively handle the dynamic interaction between fluid and solid under high-speed flow or extreme conditions. Therefore, the processing accuracy and efficiency in fluid-structure interaction remain a challenge. Summary of the invention

[0004] The present application proposes a fluid-solid coupling method, apparatus, computer equipment and storage medium to optimize the material parameters of a sensor embedded in a viscoelastic material to improve the measurement accuracy of the mechanical state of the charge structure, thereby reducing the complexity of the evaluation of the integrity of the engine charge structure.

[0005] In a first aspect, a fluid-solid coupling method is provided, comprising:

[0006] Creating a geometric model of a target object, wherein the geometric model includes a fluid domain of the target object and a solid domain of the target object;

[0007] Meshing the geometric model to obtain a discretized mesh of the geometric model, and determining a coupling interface, wherein the coupling interface includes smooth particles and finite elements;

[0008] Acquiring physical properties of the geometric model, and generating a coupling time step of the coupling interface based on the physical properties;

[0009] Dynamically adjusting the coupling time step according to the particle spacing of the discretized grid and the size of the finite element, wherein the coupling time step is the smaller time of the particle time step and the unit time step of the coupling interface;

[0010] Under the constraint of the coupling time step, numerically integrating the smooth particles and the finite elements, and performing integral correction on the smooth particles to impose boundary conditions on non-failed finite elements in the coupling interface;

[0011] defining a momentum equation that incorporates artificial viscosity and contact potential functions;

[0012] Under the constraints of preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step, the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface are coupled and updated.

[0013] In a second aspect, a fluid-solid coupling device is provided, comprising:

[0014] A creation module, used for creating a geometric model of a target object, wherein the geometric model includes a fluid domain of the target object and a solid domain of the target object;

[0015] A partitioning module, used for performing mesh partitioning on the geometric model to obtain a discretized mesh of the geometric model and determine a coupling interface, wherein the coupling interface includes smooth particles and finite elements;

[0016] An acquisition module, used for acquiring physical properties of the geometric model and generating a coupling time step of the coupling interface based on the physical properties;

[0017] An adjustment module, used for dynamically adjusting the coupling time step according to the particle spacing of the discretized grid and the size of the finite element, wherein the coupling time step is the smaller time of the particle time step and the unit time step of the coupling interface;

[0018] An integration module, used for numerically integrating the smooth particles and the finite elements under the constraint of the coupling time step, and performing integral correction on the smooth particles to impose boundary conditions on the non-failed finite elements in the coupling interface;

[0019] A definition module for defining a momentum equation, wherein the momentum equation incorporates artificial viscosity and contact potential functions;

[0020] The first updating module is used to couple and update the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface under the constraints of the preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step.

[0021] In a third aspect, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned fluid-structure coupling method when executing the computer program.

[0022] In a fourth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned fluid-structure coupling method are implemented.

[0023] The present application provides a fluid-solid coupling method, apparatus, computer equipment and storage medium, which create a geometric model of a target object, wherein the geometric model includes a fluid domain of the target object and a solid domain of the target object; mesh the geometric model to obtain a discretized grid of the geometric model, and determine a coupling interface, wherein the coupling interface includes smooth particles and finite elements; obtain physical properties of the geometric model, and generate a coupling time step of the coupling interface based on the physical properties; dynamically adjust the coupling time step according to the particle spacing of the discretized grid and the size of the finite element, wherein the coupling time step is the smaller time of the particle time step and the unit time step of the coupling interface; numerically integrate the smooth particles and the finite element under the constraint of the coupling time step, and perform integral correction on the smooth particles to apply boundary conditions to the non-failed finite elements in the coupling interface; define a momentum equation, wherein the momentum equation incorporates artificial viscosity and contact potential function; and couple and update the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface under the constraints of preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step. In the fluid-solid coupling scheme provided in the present application, the coupling time step is dynamically adjusted according to the particle spacing and the size of the finite element, and the smooth particles are integrally corrected after the coupling time step ends to apply boundary conditions to the non-failed finite elements in the coupling interface, and the artificial viscosity and contact potential function are integrated into the momentum equation. Under the constraints of the preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step, the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface are coupled and updated. The shock wave is a propagation phenomenon of a discontinuous peak in a continuous medium. When passing through the coupling interface, the physical properties such as pressure, temperature, and density will undergo a jump change. The SPH-FEM coupling algorithm can ensure the numerical continuity of the shock wave on the coupling interface, reasonably allocate computing resources, accurately capture the pressure, temperature, density and other values ​​on both sides of the coupling interface, and accurately simulate the shock wave propagation law and material dynamic response process between the fluid and the solid during impact initiation. It can be seen that the processing accuracy and efficiency in the fluid-solid coupling process can be improved by dynamically adjusting the coupling time step, performing integral correction on smooth particles, and adding artificial viscosity and contact potential functions to the momentum equation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 An application environment diagram of the fluid-solid coupling method provided in an embodiment of the present application;

[0026] Figure 2 A flow chart of a fluid-solid coupling method provided in an embodiment of the present application;

[0027] Figure 3 A schematic diagram of the SPH continuous velocity algorithm provided in an embodiment of the present application;

[0028] Figure 4 A schematic diagram of the SPH particle contact force algorithm provided in an embodiment of the present application;

[0029] Figure 5 A schematic diagram of a smooth function support domain provided in an embodiment of the present application;

[0030] Figure 6 A schematic diagram of a smooth particle coupled to a finite element provided in an embodiment of the present application;

[0031] Figure 7 A schematic diagram of two objects in contact provided in an embodiment of the present application;

[0032] Figure 8 A schematic diagram of contact force application provided in an embodiment of the present application;

[0033] Fig. 9 A schematic diagram of the variation law of the interparticle distance and the contact potential function provided in the embodiment of the present application;

[0034] Fig.10 A search schematic diagram of a linked list search algorithm provided in an embodiment of the present application;

[0035] Fig.11 A schematic diagram of a square bar geometric model and mesh division provided in an embodiment of the present application;

[0036] Fig.12 A schematic diagram of the selection of reference SPH particles and finite element nodes provided in the embodiments of the present application;

[0037] Fig.13 A schematic diagram of speed change at a coupling interface provided in an embodiment of the present application;

[0038] Fig.14A schematic diagram of stress changes at a coupling interface provided in an embodiment of the present application;

[0039] Fig.15 A schematic diagram of the structure of a three-dimensional cantilever beam provided in an embodiment of the present application;

[0040] Fig.16 A schematic diagram showing a comparison of node displacements of a three-dimensional cantilever beam provided in an embodiment of the present application;

[0041] Fig.17 A schematic diagram of the 7.62mm bullet warhead size and grid division provided in an embodiment of the present application;

[0042] Fig.18 Schematic diagram of the target plate SPH-FEM coupling model provided in the embodiment of the present application;

[0043] Fig.19 A schematic diagram of the high-speed photography results of a bullet impacting a target plate document provided in an embodiment of the present application;

[0044] Fig. 20 A schematic diagram showing the comparison of the residual velocity theoretical analysis, numerical simulation and experimental results provided in the embodiments of the present application;

[0045] Fig.21 A schematic diagram of the SPH and FEM interface coupling algorithm flow provided in the embodiment of the present application;

[0046] Fig. 22 A schematic diagram of the SPH and FEM interface contact algorithm flow chart provided in the embodiment of the present application;

[0047] Fig.23 A structural block diagram of a fluid-solid coupling device provided in an embodiment of the present application;

[0048] Fig.24 A structural block diagram of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are 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 are within the scope of protection of the present invention.

[0050] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0051] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0052] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0053] The fluid-solid coupling method provided by the embodiment of the present invention can be applied in Figure 1 In an application environment. The computer device 110 communicates with the server 120 via the network 130. The computer device 110 can create a geometric model of the target object, the geometric model including a fluid domain of the target object and a solid domain of the target object;

[0054] Meshing the geometric model to obtain a discretized mesh of the geometric model, and determining a coupling interface, wherein the coupling interface includes smooth particles and finite elements;

[0055] Acquiring physical properties of the geometric model, and generating a coupling time step of the coupling interface based on the physical properties;

[0056] Dynamically adjusting the coupling time step according to the particle spacing of the discretized grid and the size of the finite element, wherein the coupling time step is the smaller time of the particle time step and the unit time step of the coupling interface;

[0057] Under the constraint of the coupling time step, numerically integrating the smooth particles and the finite elements, and performing integral correction on the smooth particles to impose boundary conditions on non-failed finite elements in the coupling interface;

[0058] defining a momentum equation that incorporates artificial viscosity and contact potential functions;

[0059] Under the constraints of the preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step, the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface are coupled and updated, and displayed through the computer device 110. In the present invention, by dynamically adjusting the coupling time step according to the particle spacing and the size of the finite element, the smooth particles are integrally corrected after the coupling time step ends, so as to apply boundary conditions to the non-failed finite elements in the coupling interface, and the artificial viscosity and contact potential function are integrated in the momentum equation. Under the constraints of the preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step, the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface are coupled and updated, so as to reasonably allocate computing resources and accurately simulate the shock wave propagation law and material dynamic response process between the fluid and the solid during impact detonation. It can be seen that by dynamically adjusting the coupling time step, integrally correcting the smooth particles, and adding the artificial viscosity and contact potential function to the momentum equation, the processing accuracy and processing efficiency in the fluid-solid coupling process can be improved. The computer device 110 may be, but is not limited to, various smart phones 110 - 1 , tablet computers 110 - 2 and notebook computers 110 - 3 . The present invention is described in detail below through specific embodiments.

[0060] See also Figure 2 As shown, Figure 2 A flow chart of a fluid-solid coupling method provided in an embodiment of the present invention is provided. The method can be applied to both a terminal and a server. This embodiment is described by applying the method to the server. The fluid-solid coupling method includes the following steps:

[0061] S101: Create a geometric model of a target object, wherein the geometric model includes a fluid domain of the target object and a solid domain of the target object.

[0062] Among them, the target object can be a square rod, a three-dimensional cantilever arm, a rifle bullet impacting a target plate, a high-speed fragment impacting a solid viscoelastic material, etc.

[0063] The geometric model of the target object can be created using numerical models or geometric modeling software, such as finite element analysis software, fluid simulation software, computer-aided design software, etc. The fluid domain refers to the spatial region occupied by the fluid in the target object. The solid domain refers to the geometric shape and physical state of the solid material in the target object.

[0064] S102: Meshing the geometric model to obtain a discretized mesh of the geometric model, and determining a coupling interface, wherein the coupling interface includes smooth particles and finite elements.

[0065] The coupling interface is the boundary area where the fluid domain and the solid domain intersect. The physical states of the smooth particles and finite element nodes are initialized on the coupling interface, such as velocity, pressure, density, displacement, etc. The properties of the background particles in the coupling interface are consistent with the properties of the finite element nodes, such as position, velocity, etc.

[0066] S103: Acquire physical properties of the geometric model, and generate a coupling time step of the coupling interface based on the physical properties.

[0067] S104: dynamically adjusting the coupling time step according to the particle spacing of the discretized grid and the size of the finite element, wherein the coupling time step is the smaller time between the particle time step and the unit time step of the coupling interface.

[0068] S105: Under the constraint of the coupling time step, numerically integrate the smooth particles and the finite elements, and perform integral correction on the smooth particles to impose boundary conditions on non-failed finite elements in the coupling interface.

[0069] In this application, the second-order accurate leapfrog method can be used to numerically integrate the particle-format Navier-Stokes equations. The specific integration steps are as follows:

[0070] The particle density, velocity and energy of the smooth particles are updated with a step size of Δt2, while the coordinates of the smooth particles are updated with Δt. The specific process is as follows:

[0071]

[0072]

[0073]

[0074]

[0075] Where Δt is the coupling time step, ρ i represents the density of smooth particle i, v i represents the velocity of smooth particle i, e i represents the energy of smooth particle i, t0 is the starting time, de i (t0) represents the differential of the energy of smooth particle i with respect to time t0.

[0076] After the smooth particle coordinates are updated, the density, velocity, and energy of the smooth particles are updated with a time step of Δt2, so that the update time of the density, velocity, and energy of the smooth particles is consistent with the update time of the smooth particle coordinates. The specific process is as follows:

[0077]

[0078]

[0079]

[0080] Where t is the current time.

[0081] It should be noted that there are two main cases of Smoothed Particle Hydrodynamics-Finite Element Method (SPH-FEM) coupling: coupling between different methods in the same medium, such as using the FEM method in some areas of the same material and the SPH method in other areas; coupling between the same method in different media, such as using the same calculation method for simulation at the interface of different materials. Since FEM relies on the grid structure for simulation, and the SPH method relies on the discrete representation of particles, data exchange and coupling calculation between the two is a technical difficulty.

[0082] Therefore, the integral correction process of smooth particles corresponding to different calculation methods for the same medium is as follows: When finite elements and smooth particles exist inside an object at the same time, they still affect each other. Although they use different calculation methods, they belong to the coupling between different calculation methods in the same medium. Add boundary smooth particles to the non-failed finite element nodes, and include the finite element nodes in the adjacent search range of the smooth particles, that is, add any smooth particles and finite element nodes to the adjacent list of smooth particles, and search within the adjacent search range. The integral correction of smooth particles is:

[0083]

[0084] Where f(x i ) is the integrand of smooth particle i, f(x j ) is the integrand of smooth particle j, N is the number of smooth particles in the support domain of smooth particle i and N n is the number of smooth particles and finite element nodes in the support domain of smooth particle i, W ij is the SPH smooth kernel function between smooth particles i and j, m j is the mass of smooth particle j, ρ j is the density of smooth particle j, m nj is the mass of the finite element node j, and ρ nj is the density of the finite element node j, representing the kernel approximation operator.

[0085] In the coupling interface, the physical quantities of the finite element nodes are determined by the boundary SPH particles, and this scheme is used to handle the coupling calculation of the non-failed finite elements and SPH particles.

[0086] Same calculation method for different media: Based on the SPH particle information update method, the continuous velocity algorithm takes into account all SPH particles in the support domain, so that the mutual influence between different media can be realized when solving the SPH momentum equation. Figure 3 As shown in Figure 1, the support domain of the particle includes particles in medium A (partA) and particles in medium B (partB). When the SPH continuous velocity algorithm is used to update the velocity of the particle, its SPH momentum equation is expressed as:

[0087]

[0088] In the formula, is the stress tensor, which is a second-order tensor, so two superscripts α and β are added to the superscript. represents the velocity gradient, Indicates partial differential calculation of smooth and function, m Bj represents the mass of particles in Part B, ρ Bj represents the density of particles in PartB, σ Bj represents the stress of the particle in Part B, N A represents the number of smooth particles in Part A that are within the support domain of particle i, N B represents the number of smooth particles in Part B that are within the support domain of particle i, Figure 3 Medium B =3.

[0089] In this application, in order to solve the penetration problem of smooth particles between different media, this paper adopts the SPH particle contact force algorithm. Figure 4 As shown in the figure, when the distance between medium A and medium B is less than 2 times the smooth length, contact force is generated, and the arrow indicates the direction of the contact force.

[0090] In one embodiment, the contact potential function can be expressed as:

[0091]

[0092] In the formula, represents the contact function, x i represents the coordinates of particle i, ρ j is the density of smooth particle j, m j is the mass of smooth particle j, K is a constant related to material properties and impact velocity, W(r ij ) represents the smooth kernel function, r ij represents the position vector of particle i and particle j, Δd avg represents the average distance between particles.

[0093] Where N represents the number of particles belonging to different bodies in the support domain of SPH particle i. A and x B When they belong to the same body, the SPH kernel function W(x A -x B ,h)=0. Δd avg is the average distance between particles. By discretizing the gradient of the contact potential function, we can get:

[0094]

[0095] In the formula, kn represents the user-defined parameter, is the gradient operator

[0096] S106: Define a momentum equation, which combines artificial viscosity and contact potential functions.

[0097] For smoothed particle hydrodynamics (SPH), the momentum equation is expressed in the form of smooth particles. Each smooth particle carries information such as mass and velocity, and the dynamic behavior of the fluid domain is simulated through the interaction between smooth particles.

[0098] For the finite element method (FEM), the momentum equation is expressed by the displacement and velocity of the finite element nodes, so as to update the motion state of the finite element nodes by solving the force balance equations on the finite element nodes.

[0099] The interaction force between the smooth particles can be obtained by calculating the momentum equation, so as to update the velocity and position of the smooth particles according to the interaction force.

[0100] For smooth particle hydrodynamics, the expression defining the momentum equation for a smooth particle is:

[0101]

[0102] For the finite element method, the momentum equation may be a fluid mechanics equation, which may be solved to obtain the acceleration of the finite element nodes, and the velocity and displacement of the finite element nodes may be updated according to the acceleration.

[0103] In this application, artificial viscosity can be introduced into the momentum equation to capture the discontinuity in the coupling process, simulate the viscous interaction between smooth particles, ensure the stability of the numerical value in the simulation process, and avoid instability in the coupling process. The expression of the artificial viscosity can be defined as:

[0104]

[0105] In the formula, v ij =v i -v j , x ij =x i -x j , c is the speed of sound of the substance, α Π and β Π is a standard constant, the factor This is used to prevent the generated values ​​from diverging when smooth particles are close to each other.

[0106] In one embodiment, the expression of the contact potential function may also be defined as:

[0107]

[0108] Where N ij is the shape function at particle i in the SPH method, b c Indicates physical strength, represents the shape function, Δρ avg Represents the average density of particles.

[0109] S107: Under the constraints of the preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step, the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface are coupled and updated.

[0110] The preset information exchange conditions may include position exchange, mass exchange, stress exchange, sound velocity exchange, and particle smoothing length. Specifically, in one embodiment, the position exchange expression may be defined as:

[0111] x p =x n

[0112] Where subscript n is the finite element unit, subscript p is the smooth particle, and X n is the position of finite element n, X p is the position of the smooth particle p.

[0113] In one embodiment, the mass exchange expression may be defined as:

[0114]

[0115] Where, subscript n is the finite element unit, p is the smooth particle, and m is n is the mass of finite element n, m p is the mass of the smooth particle p, N e is the number of elements connected to the finite element node, N nis the number of finite element nodes of the finite element unit, r0 is the initial unit size, ρ ei Represents the cell density, V ei Represents the unit volume.

[0116] In one embodiment, the speed exchange expression may be defined as:

[0117] v p =v n

[0118] Where subscript n is the finite element unit, subscript p is the smooth particle, V n is the velocity of finite element n, V p is the velocity of the smooth particle p.

[0119] In one embodiment, the stress exchange expression may be defined as:

[0120]

[0121] Where subscript n is the finite element node, subscript p is the smooth particle, σ n is the stress of finite element n, σ p is the stress of the smooth particle p, subscript g is the Gaussian integration point, subscript e is the finite element unit, and w gi is the weighting coefficient, N e is the number of elements connected to the finite element node, N g is the number of Gaussian integration points in the unit, σ ei is the stress tensor.

[0122] In one embodiment, the sound speed exchange expression can be defined as:

[0123] c p =c n

[0124] Where, subscript n is the finite element unit, subscript p is the smooth particle, and c n is the finite element n, c p is the speed of sound of the smooth particle p.

[0125] In one embodiment, the virtual particle smooth length expression may be defined as:

[0126]

[0127] In the formula, subscript p refers to smooth particles, h p is the velocity of the smooth particle p, subscript e is the finite element unit, N e is the number of elements connected to the finite element nodes, r0 is the initial element size, α is a constant, and d is the dimension.

[0128] In some embodiments, the physical properties include interparticle spacing, the speed of sound in the fluid domain, the size of the finite element, the elastic modulus, density and safety factor of the material, and the step of generating the coupling time step of the coupling interface based on the physical properties includes:

[0129] (11) The particle time step is calculated based on the inter-particle distance and the speed of sound in the fluid domain.

[0130] (12) calculating a unit time step based on the size of the finite element, the elastic modulus of the material, the density, and the safety factor;

[0131] (13) Taking the smaller time between the particle time step and the unit time step as the coupling time step.

[0132] The particle time step can be calculated according to the following expression:

[0133] Δt SPH =min(λ1Δt cv ,λ2Δt f )Δt cv

[0134] In the formula, λ1 is a constant, λ2 is a constant, c is the speed of sound, and f is the acceleration.

[0135] The unit time step Δt can be calculated according to the following expression FEM :

[0136]

[0137] Where, L min is the minimum element size, ρ is the density, v is the Poisson's ratio, λ3 is a constant, and E is the elastic modulus.

[0138] The coupling time step Δt can be determined according to the following expression SPH-FEM :

[0139] Δt SPH-FEM =min{Δt SPH ,Δt FEM}

[0140] In the formula, Δt SPH-FEM is the coupling time step, Δt SPH is the particle time step, Δt FEM is the unit time step.

[0141] In some embodiments, the coupling and updating of the physical properties of the smooth particles, the finite element nodes, and the background particles in the coupling interface under the constraints of the preset information exchange conditions, the momentum equation, the boundary conditions, and the coupling time step includes:

[0142] (21) Under the constraints of preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step, the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface are updated according to the mass conservation equation, the momentum conservation equation, the energy conservation equation, the equilibrium equation, the motion equation and the constitutive equation.

[0143] Among them, in the fluid-solid coupling process, it is necessary to synchronously update the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface based on the information exchange conditions, momentum equations, boundary conditions, mass conservation equations, momentum conservation equations, energy conservation equations, equilibrium equations, motion equations and constitutive equations in each coupling time step to ensure that the dynamic response process in the coupling process is correctly captured and the processing accuracy in the coupling process is improved.

[0144] The mass conservation equation can be a continuity equation, that is, the continuity equation is used to ensure the conservation of mass flow between particles.

[0145] The stability conditions of FEM and SPH maintain the stability of the calculation.

[0146] At each time iteration, the coupled time step is re-evaluated and adjusted based on the current particle spacing and finite element size.

[0147] In some embodiments, the updating of the physical properties of the smooth particles, the finite element nodes, and the background particles in the coupling interface according to the mass conservation equation, the momentum conservation equation, the energy conservation equation, the equilibrium equation, the motion equation, and the constitutive equation comprises:

[0148] (31) updating the mass, coordinates, velocity and energy of the smooth particle and the coordinates and loads of the finite element nodes at the coupling interface according to the mass conservation equation, momentum conservation equation and energy conservation equation;

[0149] (32) updating the mass, coordinates, velocity and energy of the background particles, and updating the displacement and load of the finite element nodes according to the equilibrium equation, the equation of motion and the constitutive equation.

[0150] The SPH kernel function W has the following three properties:

[0151] Regularization:

[0152]

[0153] Where W(x-x',h) represents the smooth kernel function, x represents the integral position, x' represents the particle position, and h represents the smooth length.

[0154] Dirac function:

[0155]

[0156] Where δ(x-x') represents the Dirac function.

[0157] Tight support:

[0158] W(xx′,h)=0,xx′>kh

[0159] Among them, k is a constant, kh is the support domain of the smooth function at point i, such as Figure 5 shown.

[0160] The spatial derivative of a smooth function f(x) is:

[0161]

[0162] From the divergence law, we know that:

[0163]

[0164]

[0165] The coupling form between SPH particles and nodes on the coupling interface is as follows: Figure 6 As shown, smooth particles (i.e., SPH fluid particles) are coupled to the finite element.

[0166] The NS equations of smooth particles at the coupling interface can be expressed as follows:

[0167]

[0168]

[0169]

[0170]

[0171]

[0172] In the formula, m bj is the mass of background particle j, ρ bj is the density of background particle j, v bj is the velocity of background particle j, σ bj is the stress tensor of background particle j, N i (x) is the shape function, Nb is the number of particles in the support domain.

[0173] In some embodiments, before the physical properties of the smooth particles, the finite element nodes, and the background particles in the coupling interface are updated according to the mass conservation equation, momentum conservation equation, energy conservation equation, equilibrium equation, motion equation, and constitutive equation under the constraints of the preset information exchange conditions, the momentum equation, the boundary conditions, and the coupling time step, the method further includes:

[0174] (41) performing contact analysis on the smooth particle and the finite element node at the coupling interface to determine a contact state;

[0175] (42) calculating the interaction force between the smooth particle and the finite element node according to the contact state;

[0176] (44) Updating the boundary conditions based on the interaction force.

[0177] Define two objects Ω A and Ω B The gap function g of the contact relationship between the two points:

[0178]

[0179] like Figure 7 As shown, where x A is the contact surface Γ CA The point on x B By x A Projected to the contact surface Γ CB Upper distance x A The nearest point.

[0180]

[0181] Where X represents the contact surface Γ CB Any point on .

[0182] The rate of change of the gap function is expressed as The contact boundary can be described as:

[0183]

[0184] The equation of motion is expressed in variational form, and the contact boundary can be described as:

[0185]

[0186] When the contact surface remains in contact, When the contact surfaces separate, t n =0.

[0187] Figure 8 The schematic diagram of the contact force when a smooth particle contacts a finite element. The contact force is generated when the distance between the finite element node and the smooth particle reaches twice the smooth length. The calculation of the contact force draws on the idea of ​​the SPH contact algorithm, treating the finite element nodes as particles, and any finite element node will also generate contact force on the particles.

[0188] Assume two objects Ω A and Ω B The constraints on are:

[0189] (In Ω=Ω A ∪Ω B within the domain)

[0190] (In Γ t On the border)

[0191] (In Γ u On the border)

[0192] In the formula, is the surface force, a is the acceleration, and b is the body force.

[0193] Define U as the function space and W as the weight function space:

[0194]

[0195]

[0196] In the formula, H 1 (Ω) is the Sobolev space of vector functions.

[0197] Will (In Ω=Ω A ∪Ω B The weight function in the domain can be obtained:

[0198]

[0199] Where σ is the Cauchy stress, ρ is the current density, a represents acceleration, b represents body force, V represents volume, and Γ represents area. represents the surface force, w represents the weight function, and the integral on the left side of the equal sign is:

[0200]

[0201] At the boundary Γ u If w=0, the integral on the left side of the equal sign can be expressed as:

[0202]

[0203] right Discrete to get:

[0204]

[0205] where w=Nd, u=Nd, N T represents the transpose of N, B T represents the transpose of physical force, d represents the differential symbol, b c represents the body force at the contact point, and N is the shape function matrix:

[0206]

[0207] where j is the particle in the support domain of particle i, N p is the number of neighboring particles in the support domain of particle i, x i The position of particle i.

[0208] Will By changing the surface integral in the form of volume integral, the contact force can be defined as:

[0209]

[0210] In one embodiment, the body force can be obtained by the gradient of the potential function, and the contact potential can be defined as:

[0211]

[0212] When x A and x B When they belong to the same body, W(x A -x B )=0, K and n are constants.

[0213] The discrete format of the above contact potential expression is:

[0214]

[0215] Where N represents the number of neighboring particles belonging to different bodies in the support domain of particle i (here, the finite element nodes are regarded as particles), r ij is the interparticle distance, Δp avg is the average of the smooth lengths between particles, and K and n are user-defined parameters.

[0216] Fig. 9 The variation law of particle spacing and contact potential function is shown, that is, the particle spacing affects the contact potential between particles.

[0217] Based on the above expression of contact potential, the contact force is defined as:

[0218]

[0219] The contact force vector can be Substitute into the formula Find:

[0220]

[0221] Using SPH particle approximation, we get:

[0222]

[0223] Finally, we get the momentum equation for the particle The contact force correction expression is:

[0224]

[0225] And the contact force correction expression of the finite element dynamics equation:

[0226]

[0227] In the formula, M represents the mass matrix, C represents the damping matrix, and K represents the stiffness matrix. represents the node acceleration, represents the node velocity and u represents the node displacement.

[0228] In some embodiments, performing contact analysis on the smooth particles and the finite element nodes at the coupling interface to determine the contact state includes:

[0229] (51) searching a search area of ​​each of the smooth particles in the coupling interface to determine a contact pair;

[0230] (52) calculating the distance between the smooth particle in the contact pair and the finite element node;

[0231] (53) If the distance is less than the distance threshold, the contact state is determined to be contact.

[0232] In one embodiment, the SPH-FEM coupling algorithm uses a particle linked list search method, such as Fig.10 As shown in the figure, first, the temporary grid settings including grid size, position, etc. are updated, and each grid is assigned a unique number before the start of each time step; then, the particles are assigned to the grid according to the current particle position in the temporary grid space; the grid number of particle i is recorded, and the adjacent grids of particle i are searched and recorded; finally, the adjacent grids are searched for particle j of i.

[0233] In some embodiments, the calculating the interaction force between the smooth particle and the finite element node according to the contact state includes:

[0234] (61) If the contact state is contact, the interaction force between the smooth particle and the finite element node is calculated according to the contact potential function model.

[0235] Among them, the contact potential function model is a mathematical model used to describe the interaction between the contact surfaces of two objects. In physics and engineering, especially in the fields of contact mechanics and materials science, the contact potential function model is used to simulate and analyze the contact behavior between objects, including elasticity, plastic deformation, friction, adhesion and other phenomena. The selection and design of the contact potential function model depends on the specific circumstances of the contact problem, including contact type, material properties, loading conditions, etc., which are not specifically limited here.

[0236] For example, the problem of one-dimensional stress wave propagation in a square bar is calculated to verify the symmetry of the SPH-FEM coupling algorithm and the continuity of physical quantities on the coupling interface. Fig.11 As shown, the rod size is 50mm×50mm×5mm, and the density ρ=7.83×10 3 kg / m 3 , Poisson's ratio υ = 0.3, elastic modulus E = 207 × 10 9 Pa. A uniform pressure P = 40 × 10 9 Pa, application time is 0~10 -6 s. In the example, the square rod is discretized into 1250 particles and 1250 hexahedral units. Fig.12 As shown, two SPH particles and two FEM nodes are selected near the coupling interface to obtain their axial velocity and axial stress data, where P1 and P2 are two SPH particles symmetrical about the center line of the rod near the coupling interface, and N1 and N2 are two FEM nodes symmetrical about the Z axis near the coupling interface. Fig.13 and Fig.14 is t = 10 × 10 -6 The velocity and stress values ​​of the particles and nodes selected at the moment. The velocity and stress curves of the SPH particles and finite element nodes along the center line of the square rod are shown respectively, where the triangles represent the velocity and stress analytical solutions obtained by the Laplace method under the same initialization conditions. The maximum velocities of the nodes, particles and analytical solutions are -577.68m / s, -534.78m / s and -529.77m / s, respectively, and the maximum stress values ​​are -27.16GPa, -27.47GPa and -25.68GPa, respectively. The stress and velocity trends of the particles and nodes on both sides of the coupling interface are consistent. The velocity and stress of the particles are smaller than those of the nodes, and have a certain lag. This is because the stress wave passes through the nodes first and then transmits to the particles. This result is in line with the laws of physics. The stress and velocity values ​​of the particles, nodes and analytical solutions are relatively consistent, which verifies the continuity of the physical quantities of the coupling algorithm on the coupling interface.

[0237] For example, Fig.15 As shown in the figure, the size of the three-dimensional cantilever beam is 10mm×10mm×90mm. One end of the cantilever beam is fixed, and the other end is subjected to a force of 10000N, acting on 10 particles or units. In order to verify the accuracy of the SPH-FEM algorithm, three examples are designed: 6000 hexahedral units and 3000 SPH particles; 9000 hexahedral units; 9000 SPH particles. The cantilever beam model parameters are shown in Table 1.

[0238]

[0239] Table 1 Material parameters of cantilever beam linear elastic model

[0240] Three observation points A, B and C are evenly spaced along the axial direction of the three-dimensional cantilever beam. The displacement time history curves of the three points in different algorithms are as follows: Fig.16 The displacement trends of the three algorithms have a high degree of overlap, which verifies the applicability of the coupling algorithm in calculating static problems.

[0241] For example, the numerical calculation of a rifle bullet impacting a 30CrMnSiA steel plate is used to test the practicality of the SPH-FEM coupling algorithm in high-speed impact problems. The bullet has a mass of 7.91 g, a caliber of 7.62 mm, a straight length of 10.75 mm, an arc length of 15.95 mm, a curved radius of 40 mm, a central angle of 25.2°, and a diameter of 1.34 mm for the top platform of the bullet. The bullet is discretized using a hexahedral mesh with a mesh number of 5872. The specific size and mesh division are as follows: Fig.17 shown.

[0242] like Fig.18 As shown, the target plate material is 30CrMnSiA steel, and the size is 250×250×4.1mm 3 The target plate is discretized into particles in the center, with a particle spacing of 0.5 mm, and a total of 28,325 particles. The target plate is surrounded by a hexahedral grid with a total of 13,056 grids.

[0243] The constitutive relation expression is:

[0244]

[0245] Where A, B, C, n, and m are material constants (e.g., A can be the initial yield stress, B can be the hardening constant, C can be the strain rate constant, n can be the hardening exponent, and m can be the thermal softening exponent), T * is the dimensionless temperature, T is the actual temperature, T0 is the room temperature, T m is the melting point of the material, r is the accumulated damage plastic strain, r=(1-D)p, p is the accumulated plastic strain, is the strain rate, is the plastic strain rate, is the equivalent strain rate. The damage variable D is a function of the equivalent cumulative plastic strain p:

[0246]

[0247] In the formula, p d is the damage threshold, p f is the plastic strain at fracture:

[0248]

[0249] Where D1, D2, D3, D4, and D5 are constants, and σ * =σ m σ eq , σ m =(σ x +σ y +σ z )3. Among them, σ m represents the average normal stress, σ eq represents the material yield strength, σ x represents the normal stress in the x direction, σ y represents the normal stress in the y direction, σ z The material parameters of the target plate are shown in Table 2.

[0250]

[0251] Table 1 Target plate material parameters

[0252] The rifle bullet is an elastic-plastic model, and the material parameters are shown in Table 3.

[0253]

[0254] Table 2 Bullet material parameters

[0255] High-speed video of the bullet hitting the target at 710 m / s Fig.19 As shown in the figure, the rifle bullet reaches the target plate at t = 0 μs and penetrates the target plate at t = 20.563 μs. In the numerical calculation, the rifle bullet touches the target plate at t = 1.1 μs and penetrates the target plate at t = 20 μs. The penetration time is 18.9 μs, which is 8.1% different from the experimental error.

[0256] The initial velocity and residual velocity values ​​of the rifle bullet from the experiment and numerical simulation are shown in Table 4. It can be seen from Table 4 that the numerical simulation results are consistent with the experimental results.

[0257]

[0258] Table 3 Residual speed simulation value vs. experimental value Definition Residual speed Vf The theoretical calculation formula is:

[0259]

[0260] In the formula, m b is the mass of the bullet, m g is the mass of the target plate punch block, W R is the energy loss, σ is the yield stress, e is the fracture strain, d b is the bullet diameter, V min The ultimate penetration speed.

[0261] In this application, by integrating the advantages of SPH and FEM, considering the physical strength of the material, and using the second-order precision frog leap method to optimize the numerical integration format, the calculation efficiency is significantly improved and the cumulative error is reduced. The linked list search method is applied to improve the recognition efficiency of particle interactions, and the SPH processing ability for complex shapes is enhanced by the completely variable smooth length algorithm. In order to alleviate the tensile instability phenomenon, artificial stress and extended smooth particle hydrodynamics (Extended Smoothed Particle Hydrodynamics, XSPH) technology are introduced. The FEM explicit dynamic equations are solved using the central difference format and the unit-level parallel algorithm. The designed time step control method ensures the stability of SPH and FEM in the coupled calculation. The coupling algorithm introduces virtual particles (background particles) to enhance the stability of the algorithm and avoid the boundary effect of SPH. The algorithm has significant advantages in dealing with local large deformation area problems, and realizes flexible response to complex deformation problems. The discretization of large deformation areas is processed as SPH particles, and the discretization of small deformation areas is processed as finite elements. Finite elements are set around SPH particles, and the application of various boundary conditions is more convenient. The contact force calculation method between SPH particles and finite elements was designed. The contact force was obtained by the gradient of the contact potential function, and the direction of the force was obtained by the gradient of the SPH smooth kernel function. The SPH-FEM coupling algorithm was used to perform numerical simulations on one-dimensional stress wave propagation, three-dimensional cantilever beams, and bullet high-speed impact on target plates. The symmetry of the SPH-FEM coupling algorithm, the continuity of the numerical values ​​of the coupling interface, the stability of static problems, the advancement of computational efficiency, and the accuracy of high-speed impact problems were verified.

[0262] Fig. 20The comparison of the theoretical analysis results, numerical simulation results and experimental measurement data of the bullet's residual velocity is shown. After in-depth comparison, we can observe that the data of numerical simulation and experimental measurement show a relatively consistent trend. It is worth noting that when the bullet impact velocity is low, there is a certain difference between the results of numerical simulation and experimental measurement and the theoretical analysis results; however, with the increase of the impact velocity, this difference gradually narrows. This phenomenon can be attributed to the fact that at higher impact velocities, the destruction form of the target plate gradually tends to rigid flat-head bullet impact destruction, which is more consistent with the applicable scenario of the theoretical formula. From the comparison of simulation and experimental results, the fluid-solid coupling algorithm provided in the application can well characterize the destructive effect of high-speed bullets on high-strength target plates.

[0263] In one embodiment of the present application, Fig.21 As shown, the SPH and FEM interface coupling algorithm flow is provided, specifically, the coupling time step is first determined, that is, the SPH time step and the FEM time step are compared, the smaller time step is used as the coupling time step, and the SPH-FEM time step is updated using the coupling time step, so as to determine the coupling time step, and then the mass conservation, momentum conservation, and energy conservation are calculated, the mass, coordinates, velocity and energy of the SPH particles are updated, and the finite element node coordinates and loads of the coupling interface are updated; at the same time, the equilibrium equation, motion equation and constitutive relationship are calculated, the background particle mass, coordinates, velocity, energy, and the finite element node displacement and load are updated. It should be noted that in each iteration process, when calculating the mass conservation, momentum conservation, and energy conservation, the SPH time step needs to be updated, and at the same time, when calculating the equilibrium equation, motion equation and constitutive relationship, the FEM time step needs to be updated, so as to redetermine the coupling time step in the next iteration process.

[0264] In one embodiment of the present application, Fig. 22As shown, the SPH and FEM interface contact algorithm process is provided, specifically, the coupling time step is first determined, that is, the SPH time step and the FEM time step are compared, the smaller time step is used as the coupling time step, and the SPH-FEM time step is updated by the coupling time step, so as to determine the coupling time step, and then, after the contact judgment is made between the smooth particles and the finite element nodes, the contact force between the smooth particles and the finite element nodes in contact is calculated; then, the mass conservation, momentum conservation, and energy conservation are calculated, the mass, coordinates, velocity and energy of the SPH particles are updated, and the coordinates and loads of the finite element nodes of the coupling interface are updated; at the same time, the equilibrium equation, the motion equation and the constitutive relationship are calculated, the background particle mass, coordinates, velocity, energy are updated, and the finite element node displacement and load are updated. It should be noted that in each iteration, the SPH time step needs to be updated when calculating the conservation of mass, momentum, and energy. At the same time, the FEM time step needs to be updated when calculating the equilibrium equations, equations of motion, and constitutive relations, so as to redefine the coupling time step in the next iteration.

[0265] The above is the fluid-solid coupling process of this application.

[0266] As mentioned above, the present application provides a fluid-solid coupling method, apparatus, computer equipment and storage medium, by establishing a finite element model based on a solid viscoelastic material specimen embedded with a sensor; performing a tensile simulation on the finite element model to obtain the stress-strain field of the solid viscoelastic material specimen embedded with the sensor; performing a mechanical state analysis on the stress-strain field to determine the strain coordination and stress concentration coefficient between the sensor and the solid viscoelastic material; and determining the target material parameters of the sensor based on the strain coordination and the stress concentration coefficient. In the fluid-solid coupling scheme provided in the present application, a finite element model is established based on a solid viscoelastic material specimen embedded with a sensor, and then a tensile simulation is performed on the finite element model to perform a mechanical state analysis on the stress-strain field of the solid viscoelastic material specimen embedded with the sensor, to determine the strain coordination and stress concentration coefficient between the sensor and the solid viscoelastic material specimen, thereby determining the target material parameters of the sensor. It can be seen that the mechanical state analysis of the stress-strain field of the solid viscoelastic material specimen embedded with the sensor is carried out through the tensile simulation of the finite element model corresponding to the solid viscoelastic material specimen embedded with the sensor, so as to optimize the material parameters of the sensor embedded in the viscoelastic material, improve the measurement accuracy of the mechanical state of the charge structure, and thus reduce the complexity of the evaluation of the integrity of the engine charge structure.

[0267] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0268] In one embodiment, a fluid-solid coupling device is provided, and the fluid-solid coupling device corresponds to the fluid-solid coupling method in the above embodiment. Fig.23 As shown, the fluid-solid coupling device comprises:

[0269] A creation module 201 is used to create a geometric model of a target object, wherein the geometric model includes a fluid domain of the target object and a solid domain of the target object;

[0270] A partitioning module 202 is used to perform mesh partitioning on the geometric model to obtain a discretized mesh of the geometric model and determine a coupling interface, wherein the coupling interface includes smooth particles and finite elements;

[0271] An acquisition module 203, used to acquire physical properties of the geometric model and generate a coupling time step of the coupling interface based on the physical properties;

[0272] An adjustment module 204, configured to dynamically adjust a coupling time step according to the particle spacing of the discretized grid and the size of the finite element, wherein the coupling time step is the smaller time of a particle time step and a unit time step of the coupling interface;

[0273] An integration module 205, configured to numerically integrate the smooth particles and the finite elements under the constraint of the coupling time step, and to perform integral correction on the smooth particles, so as to impose boundary conditions on the non-failed finite elements in the coupling interface;

[0274] A definition module 206, for defining a momentum equation, wherein the momentum equation incorporates artificial viscosity and contact potential functions;

[0275] The first updating module 207 is used to couple and update the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface under the constraints of the preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step.

[0276] In the fluid-solid coupling scheme provided in the present application, the coupling time step is dynamically adjusted according to the particle spacing and the size of the finite element, and the smooth particles are integrally corrected after the coupling time step ends to apply boundary conditions to the non-failed finite elements in the coupling interface, and the artificial viscosity and contact potential function are integrated in the momentum equation. Under the constraints of the preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step, the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface are coupled and updated, which can reasonably allocate computing resources and accurately simulate the shock wave propagation law and material dynamic response process between the fluid and the solid during impact detonation. It can be seen that by dynamically adjusting the coupling time step, integrally correcting the smooth particles, and adding artificial viscosity and contact potential functions to the momentum equation, the processing accuracy and efficiency in the fluid-solid coupling process can be improved.

[0277] Optionally, in some embodiments of the present application, the physical properties include interparticle spacing, the speed of sound in the fluid domain, the size of the finite element, the elastic modulus, density and safety factor of the material, and the acquisition module includes:

[0278] A first calculation submodule, configured to calculate a particle time step based on the particle distance and the sound speed of the fluid domain;

[0279] A second calculation submodule, configured to calculate a unit time step based on the size of the finite element, the elastic modulus of the material, the density and the safety factor;

[0280] The first determination submodule is used to take the smaller time between the particle time step and the unit time step as the coupling time step.

[0281] Optionally, in some embodiments of the present application, the first update module includes:

[0282] An updating submodule is used to update the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface according to the mass conservation equation, momentum conservation equation, energy conservation equation, equilibrium equation, motion equation and constitutive equation under the constraints of preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step.

[0283] Optionally, in some embodiments of the present application, the updating submodule includes:

[0284] A first updating unit, used for updating the mass, coordinates, velocity and energy of the smooth particle and the coordinates and loads of the finite element nodes at the coupling interface according to the mass conservation equation, the momentum conservation equation and the energy conservation equation;

[0285] The second updating unit is used to update the mass, coordinates, velocity and energy of the background particles according to the equilibrium equation, the motion equation and the constitutive equation, and to update the displacement and load of the finite element node.

[0286] Optionally, in some embodiments of the present application, it further includes:

[0287] An analysis module is used to perform contact analysis on the smooth particles and the finite element nodes at the coupling interface to determine a contact state;

[0288] A calculation module, used for calculating the interaction force between the smooth particle and the finite element node according to the contact state;

[0289] The second updating module is used to update the boundary condition according to the interaction force.

[0290] Optionally, in some embodiments of the present application, the analysis module includes:

[0291] A search submodule, used for searching a search area of ​​each of the smooth particles in the coupling interface to determine a contact pair;

[0292] A third calculation submodule, used for calculating the distance between the smooth particle in the contact pair and the finite element node;

[0293] The second determining submodule is configured to determine that the contact state is contact if the distance is less than a distance threshold.

[0294] Optionally, in some embodiments of the present application, the calculation module includes:

[0295] The fourth calculation submodule is used to calculate the interaction force between the smooth particle and the finite element node according to a contact potential function model if the contact state is contact.

[0296] In one embodiment, a computer device is provided, the internal structure diagram of which can be as follows: Fig.24 As shown. The computer device includes a processor, a memory, a network interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with an external server through a network connection. When the computer program is executed by the processor, a function or step of a fluid-solid coupling method is implemented.

[0297] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the following steps are implemented:

[0298] A geometric model of a target object is created, the geometric model includes a fluid domain of the target object and a solid domain of the target object; the geometric model is meshed to obtain a discretized mesh of the geometric model, and a coupling interface is determined, the coupling interface includes smooth particles and finite elements; the physical properties of the geometric model are obtained, and a coupling time step of the coupling interface is generated based on the physical properties; the coupling time step is dynamically adjusted according to the particle spacing of the discretized mesh and the size of the finite element, wherein the coupling time step is the smaller time of the particle time step and the unit time step of the coupling interface; under the constraint of the coupling time step, the smooth particles and the finite elements are numerically integrated, and the smooth particles are integrally corrected to impose boundary conditions on the non-failed finite elements in the coupling interface; a momentum equation is defined, the momentum equation incorporates artificial viscosity and contact potential function; under the constraints of preset information exchange conditions, momentum equations, boundary conditions and coupling time steps, the physical properties of smooth particles, finite element nodes and background particles in the coupling interface are coupled and updated.

[0299] In the fluid-solid coupling scheme provided in the present application, the coupling time step is dynamically adjusted according to the particle spacing and the size of the finite element, and the smooth particles are integrally corrected after the coupling time step ends to apply boundary conditions to the non-failed finite elements in the coupling interface, and the artificial viscosity and contact potential function are integrated in the momentum equation. Under the constraints of the preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step, the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface are coupled and updated, which can reasonably allocate computing resources and accurately simulate the shock wave propagation law and material dynamic response process between the fluid and the solid during impact detonation. It can be seen that by dynamically adjusting the coupling time step, integrally correcting the smooth particles, and adding artificial viscosity and contact potential functions to the momentum equation, the processing accuracy and efficiency in the fluid-solid coupling process can be improved.

[0300] In one embodiment, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the following steps are implemented:

[0301] A geometric model of a target object is created, the geometric model includes a fluid domain of the target object and a solid domain of the target object; the geometric model is meshed to obtain a discretized mesh of the geometric model, and a coupling interface is determined, the coupling interface includes smooth particles and finite elements; the physical properties of the geometric model are obtained, and a coupling time step of the coupling interface is generated based on the physical properties; the coupling time step is dynamically adjusted according to the particle spacing of the discretized mesh and the size of the finite element, wherein the coupling time step is the smaller time of the particle time step and the unit time step of the coupling interface; under the constraint of the coupling time step, the smooth particles and the finite elements are numerically integrated, and the smooth particles are integrally corrected to impose boundary conditions on the non-failed finite elements in the coupling interface; a momentum equation is defined, the momentum equation incorporates artificial viscosity and contact potential function; under the constraints of preset information exchange conditions, momentum equations, boundary conditions and coupling time steps, the physical properties of smooth particles, finite element nodes and background particles in the coupling interface are coupled and updated.

[0302] In the fluid-solid coupling scheme provided in the present application, the coupling time step is dynamically adjusted according to the particle spacing and the size of the finite element, and the smooth particles are integrally corrected after the coupling time step ends to apply boundary conditions to the non-failed finite elements in the coupling interface, and the artificial viscosity and contact potential function are integrated in the momentum equation. Under the constraints of the preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step, the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface are coupled and updated, which can reasonably allocate computing resources and accurately simulate the shock wave propagation law and material dynamic response process between the fluid and the solid during impact detonation. It can be seen that by dynamically adjusting the coupling time step, integrally correcting the smooth particles, and adding artificial viscosity and contact potential functions to the momentum equation, the processing accuracy and efficiency in the fluid-solid coupling process can be improved.

[0303] It should be noted that the above functions or steps that can be implemented by the computer-readable storage medium or computer device can refer to the relevant descriptions on the server side and the client side in the aforementioned method embodiment. To avoid repetition, they will not be described one by one here.

[0304] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0305] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0306] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A fluid-solid coupling method, characterized in that: include: Creating a geometric model of a target object, wherein the geometric model includes a fluid domain of the target object and a solid domain of the target object; Meshing the geometric model to obtain a discretized mesh of the geometric model, and determining a coupling interface, wherein the coupling interface includes smooth particles and finite elements; Acquiring physical properties of the geometric model, and generating a coupling time step of the coupling interface based on the physical properties; Dynamically adjusting the coupling time step according to the particle spacing of the discretized grid and the size of the finite element, wherein the coupling time step is the smaller time of the particle time step and the unit time step of the coupling interface; Under the constraint of the coupling time step, numerically integrating the smooth particles and the finite elements, and performing integral correction on the smooth particles to impose boundary conditions on non-failed finite elements in the coupling interface; defining a momentum equation that incorporates artificial viscosity and contact potential functions; Under the constraints of preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step, the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface are coupled and updated.

2. The fluid-structure coupling method according to claim 1, characterized in that: The physical properties include particle spacing, the speed of sound in the fluid domain, the size of the finite element, the elastic modulus, density and safety factor of the material, and the coupling time step of generating the coupling interface based on the physical properties includes: Calculating a particle time step based on the inter-particle distance and the speed of sound in the fluid domain; Calculating a unit time step based on the size of the finite element, the elastic modulus of the material, the density and the safety factor; The smaller time between the particle time step and the unit time step is taken as the coupling time step.

3. The fluid-structure coupling method according to claim 1, characterized in that: The coupling and updating of the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface under the constraints of the preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step includes: Under the constraints of preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step, the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface are updated according to the mass conservation equation, the momentum conservation equation, the energy conservation equation, the equilibrium equation, the motion equation and the constitutive equation.

4. The fluid-structure coupling method according to claim 3, characterized in that: The coupling and updating of the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface according to the mass conservation equation, the momentum conservation equation, the energy conservation equation, the equilibrium equation, the motion equation and the constitutive equation includes: updating the mass, coordinates, velocity and energy of the smooth particle and the coordinates and loads of the finite element nodes at the coupling interface according to the mass conservation equation, momentum conservation equation and energy conservation equation; The mass, coordinates, velocity and energy of the background particles are updated according to the equilibrium equation, the motion equation and the constitutive equation, and the displacement and load of the finite element nodes are updated.

5. The fluid-structure coupling method according to claim 3, characterized in that: Before the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface are updated according to the mass conservation equation, momentum conservation equation, energy conservation equation, equilibrium equation, motion equation and constitutive equation under the constraints of the preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step, the method further includes: Performing contact analysis on the smooth particles and the finite element nodes at the coupling interface to determine a contact state; Calculating the interaction force between the smooth particle and the finite element node according to the contact state; The boundary condition is updated according to the interaction force.

6. The fluid-structure coupling method according to claim 5, characterized in that: The step of performing contact analysis on the smooth particles and the finite element nodes at the coupling interface to determine the contact state includes: Searching a search area of ​​each of the smooth particles in the coupling interface to determine a contact pair; calculating the distance between the smooth particle and the finite element node in the contact pair; If the distance is less than a distance threshold, the contact state is determined to be contact.

7. The fluid-structure coupling method according to claim 5, characterized in that: The calculating the interaction force between the smooth particle and the finite element node according to the contact state comprises: If the contact state is contact, the interaction force between the smooth particle and the finite element node is calculated according to a contact potential function model.

8. A fluid-solid coupling device, characterized in that: include: A creation module, used for creating a geometric model of a target object, wherein the geometric model includes a fluid domain of the target object and a solid domain of the target object; A partitioning module, used for performing mesh partitioning on the geometric model to obtain a discretized mesh of the geometric model and determine a coupling interface, wherein the coupling interface includes smooth particles and finite elements; An acquisition module, used for acquiring physical properties of the geometric model and generating a coupling time step of the coupling interface based on the physical properties; An adjustment module, used for dynamically adjusting the coupling time step according to the particle spacing of the discretized grid and the size of the finite element, wherein the coupling time step is the smaller time of the particle time step and the unit time step of the coupling interface; An integration module, used for numerically integrating the smooth particles and the finite elements under the constraint of the coupling time step, and performing integral correction on the smooth particles to impose boundary conditions on the non-failed finite elements in the coupling interface; A definition module for defining a momentum equation, wherein the momentum equation incorporates artificial viscosity and contact potential functions; The first updating module is used to couple and update the physical properties of the smooth particles, the finite element nodes and the background particles in the coupling interface under the constraints of the preset information exchange conditions, the momentum equation, the boundary conditions and the coupling time step.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the fluid-structure coupling method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the fluid-structure coupling method according to any one of claims 1 to 7 are implemented.

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