Flexible biological and interception model construction method and simulation device based on particle contact

Abstract

This invention discloses a method and simulation device for constructing a flexible biological interception model based on particle contact. Based on a discrete element particle contact model of the target marine organism, the contact model parameters are improved and determined according to various parameters of the marine organism. A flexible contact model is combined with a particle replacement model to generate a flexible discrete element model of the target marine organism, constructing a target marine organism community. The interception effectiveness of the net against the target marine organism is simulated and evaluated using a finite element / discrete element coupled computational method. The discrete element particle contact model in this invention combines the high efficiency of discrete element computation with the flexibility of biological materials, enabling accurate and rapid simulation and acquisition of results such as deformation, fragmentation, and escape of marine organisms under the action of the net. Based on this, the interaction mechanism between the net and the marine organism can be analyzed. This invention not only fills the gap in the description of biological materials using discrete element computation but also contributes to the research on the mechanism of net interception of marine organisms.

Description

Technical Field

[0001] This invention belongs to the field of biological and biological interception simulation technology, specifically relating to a method and simulation device for constructing flexible biological and interception models based on particle contact. Background Technology

[0002] Jellyfish are common small aquatic organisms characterized by their high flexibility and fragility. Nuclear power plant intake canal cascade filtration systems utilize jellyfish traps. Traditional trap design relies on experience and simple hydrodynamic analysis. However, due to the small size and large number of jellyfish, and their susceptibility to deformation and breakage under the influence of the trap and water flow, the trap's effectiveness is difficult to predict accurately using conventional methods. Traditional hydrodynamic analysis methods are insufficient for analyzing the interaction mechanism between the trap and the jellyfish, and there is a lack of methods for constructing a model of jellyfish flexibility and breakage, thus failing to provide strong guidance for the design of nuclear power plant intake canal cascade filtration systems. Therefore, determining the jellyfish motion morphology under the influence of water flow, and accurately simulating the jellyfish's movement in the water flow and its interaction with the trap, is crucial for improving the efficiency and accuracy of trap configuration design.

[0003] Current simulation technologies are mostly used for simulating the capture of larger aquatic organisms, while simulation studies for smaller organisms like jellyfish are relatively limited. In simulations, direct fluid-structure interaction analysis of the interaction between jellyfish and nets fails to reflect jellyfish breakage, making it difficult to directly apply to jellyfish community simulations. Furthermore, it is computationally expensive, and existing simulation technologies rarely conduct behavioral simulations of high-precision jellyfish community models. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies and achieve high-precision simulation assessment and interception of small, flexible, and easily damaged marine organisms, this invention adopts the following technical solution:

[0005] The method for constructing flexible biological models based on particle contact includes the following steps:

[0006] Step S1: Obtain various parameters of the target organism, including stress-strain curves, stiffness, and thickness, and preliminarily set the biological model parameters based on the obtained target organism parameters;

[0007] Step S2: Based on the various parameters of the target organism, calibrate the contact model parameters through simulation; set the diameter of the large particles according to the main body size of the target organism, set the diameter of the small particles according to the geometry of the target organism, calculate the particle coordinates based on the diameter of the small particles and the contact radius, compile the corresponding dynamic link library, replace the large particles with small particles and generate bonding bonds; generate the discrete element model of the target organism through the particles of the target organism shape and the particle bonding bonds.

[0008] Further, in step S2, a contact model of the target organism is constructed, and the contact model is calibrated based on the deformation results of the target organism. The contact model includes:

[0009] The first result is obtained by multiplying the ratio of twice the particle tangential torque to the equivalent moment of inertia at the contact point by the particle contact radius. The second result is obtained by taking the ratio of the negative particle normal force to the effective area of ​​the particle stress calculation. The product of the sum of the first and second results and the normal stress intensity limit adjustment factor is greater than the normal shear stress of the particle bonding bond.

[0010] The third result is obtained by multiplying the ratio of the particle normal torque to the equivalent moment of inertia at the contact point by the particle contact radius. The fourth result is obtained by taking the ratio of the negative particle tangential force to the effective area of ​​the particle stress calculation. The product of the sum of the third and fourth results and the tangential stress intensity limit adjustment factor is greater than the tangential shear stress of the particle bonding bond.

[0011] Furthermore, the particle normal force is obtained by the normal force on the particle under the time step micro-element. The normal force on the particle under the time step micro-element is obtained by multiplying the normal relative displacement component with the equivalent spring tension coefficient, adding the product of the normal acceleration and the equivalent damping coefficient, multiplying the sum of the two by the spring resistance adjustment coefficient, and then adding the product of the particle normal velocity, the normal stiffness of the particle bonding bond, the effective area of ​​the particle stress calculation, the time step, and the negative conventional adjustment coefficient.

[0012] The tangential force of the particle is obtained by the tangential force on the particle under the time step micro-element. The tangential force on the particle under the time step micro-element is obtained by multiplying the tangential relative displacement component and the equivalent spring tension coefficient, adding the product of the tangential acceleration and the equivalent damping coefficient, multiplying the sum of the two by the spring resistance adjustment coefficient, and then adding the product of the particle tangential velocity, the tangential stiffness of the particle bonding bond, the effective area of ​​the particle stress calculation, the time step, and the negative conventional adjustment coefficient.

[0013] The normal torque of the particles is obtained by the normal torque on the particles under the time step micro-element. The normal torque on the particles under the time step micro-element is obtained by multiplying the negative normal angular velocity of the particles by the tangential stiffness of the particle bonding bond, the equivalent rotational inertia of the contact point, and the time step.

[0014] The tangential torque of the particles is obtained by multiplying the tangential torque of the particles under the time step micro-element by multiplying the negative tangential angular velocity of the particles by the normal stiffness of the particle bonding bond, half of the equivalent rotational inertia of the contact point, and the time step.

[0015] The effective area for calculating particle stress is obtained by multiplying the square of the particle's contact radius by π.

[0016] The equivalent moment of inertia of the contact point is obtained by multiplying the fourth power of the contact radius of the particle by half of π.

[0017] The contact model formula is as follows:

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026] in, This represents the normal force on the particle at the current time step, i.e., the normal force on the particle at the current time step. This represents the standard adjustment factor. Represents the normal velocity of the particle. The normal stiffness of the particle bond is represented by A, where A represents the effective area for calculating particle stress. Indicates the time step. This represents the spring resistance adjustment coefficient, which can be increased accordingly when the target has a high degree of flexibility and obvious elastic behavior. The value of , The suggested value range is, but not limited to, 0~10. Indicates the equivalent spring tension coefficient. Represents the relative displacement components in the normal direction. This represents the equivalent damping coefficient. Indicates normal acceleration. This represents the tangential force on the particle at the current time step, i.e., the tangential force on the particle at the current time step. This indicates the tangential velocity of the particle. This represents the tangential stiffness of the particle bonding bond. This represents the relative displacement component in the tangential direction. Indicates tangential acceleration. This represents the normal torque on the particle at the time step infinitesimal element, i.e., the normal torque of the particle at the current time step. This represents the normal angular velocity of the particle. This represents the equivalent moment of inertia at the point of contact. This represents the tangential torque on the particle at the time step infinitesimal element, i.e., the tangential torque of the particle at the current time step. This represents the tangential angular velocity of the particle. This indicates the contact radius of the particles, i.e., the radius range within which adhesive bonds are formed. This represents the normal shear stress of the particle bonding bond. The stress intensity limit adjustment factor in the normal direction. This represents the tangential shear stress of the particle bonding bond. This represents the stress intensity limit adjustment factor in the tangential direction. These are all material flexibility parameter adjustment factors and model parameters. The flexibility parameter adjustment factors can be simulated and calibrated according to the flexibility of the target material and can be changed according to the softness of the target biological tissue. The stiffness can be selected according to the properties of the target biological material. The unit is N / m. 3 .

[0027] Furthermore, when the normal and tangential shear stresses exceed predefined values, the bond is broken, and the target biological discrete element model ruptures.

[0028] Furthermore, the geometry of the target organism includes average thickness or partition thickness. For target organisms with uniform thickness, the diameter of small particles is taken as the average thickness. For target organisms with inconsistent thickness, the average thickness of partitions is taken as the diameter of small particles.

[0029] Furthermore, there is a certain gap between the small particles, and the gap makes the distance between the center of the particles less than or equal to the contact radius.

[0030] Furthermore, the adhesive bond is a bond that forms with damping and spring-like properties with other small particles within the contact radius of the small particles.

[0031] The flexible biological model construction device based on particle contact includes: a parameter acquisition module, a model calibration module, an initial particle generation module, a particle replacement coordinate generation module, a biological community construction module, and a flexible bonding bond generation module. Each module is executed sequentially according to the flexible biological model construction method based on particle contact to construct the model of the target organism.

[0032] The method for constructing a flexible biological interception model based on particle contact involves simulating interception using a biological model constructed according to the aforementioned method. The simulation interception includes the following steps:

[0033] Step S3: Construct the target organism community; based on the shape of the target organism, use spherical particles to fit the geometry of the target organism, and set the initial position of the target organism in the fluid domain; by replacing large particles with small particles, generate a set of discrete element models of the target organism with the shape of the target organism and particle bonding bonds;

[0034] Step S4: Simulate and analyze the interception of target organisms by the barrier net; construct the interception device as a geometric solid model, import the shape of the interception device into the open channel solid model, obtain the fluid domain calculation model by Boolean difference with the water channel solid model, and thus extract the fluid domain. The fluid domain inlet is the open channel pressure inlet, and the fluid domain outlet is the ordinary pressure outlet; import the model particles of the target organism group into the corresponding position of the liquid level on the side of the inlet of the interception device, set the open channel inlet pressure and inlet free liquid level height, and use the bidirectional coupling method of computational fluid dynamics (CFD) and discrete element method to simulate and analyze the interception mechanism of the interception device on the target organisms.

[0035] The device for constructing a flexible biological interception model based on particle contact includes an interception mechanism analysis module. The interception mechanism analysis module constructs an interception model according to the aforementioned flexible biological interception model construction method based on particle contact, and performs simulated interception of the target biological group.

[0036] The advantages and beneficial effects of this invention are as follows:

[0037] This invention utilizes a particle contact model to construct a discrete element particle model of marine organisms. Through the calibrated marine organism model, various flexibility and rigidity of marine organisms can be accurately and quickly simulated. Based on this, a target marine organism community model is constructed, and a two-way coupled finite element / discrete element calculation method is used to accurately analyze the excitation of the action of the net intercepting marine organisms. This achieves high-precision construction of the discrete element particle model of marine organisms, and further analysis of the interaction mechanism of marine organism interception, thereby significantly improving the scientificity and reliability of the net design and providing strong technical support for related engineering applications. Attached Figure Description

[0038] Figure 1 This is a flowchart of the method in an embodiment of the present invention.

[0039] Figure 2 This is a typical jellyfish diagram of a nuclear power plant that causes disasters, as described in this embodiment of the invention.

[0040] Figure 3 This is a simplified geometric model diagram of a jellyfish established in an embodiment of the present invention.

[0041] Figure 4 This is a diagram of a flexible jellyfish particle model for particle fitting established in an embodiment of the present invention.

[0042] Figure 5 This is a schematic diagram of the initial state of the jellyfish colony in an embodiment of the present invention.

[0043] Figure 6 This is a schematic diagram illustrating the jellyfish swarm interception mechanism and interception effect in an embodiment of the present invention.

[0044] Figure 7 A schematic diagram of the device in an embodiment of the present invention. Detailed Implementation

[0045] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0046] To address the difficulties in obtaining deformation results of existing interception nets and the inability of existing simulation models to perform high-precision simulation evaluation of the effectiveness of interception nets against shrimp, this invention proposes a method for constructing a flexible biological interception model based on particle contact, such as... Figure 1 As shown, it includes the following steps:

[0047] Step S1: Obtain various parameters of the target organism, and preliminarily set the parameters of the biological model based on the obtained target organism parameters; specifically, determine various parameters of the target marine organism using physical experiments, including the following steps:

[0048] Step S101: Conduct physical experiments on the target organism to obtain parameters. The physical experiments include: multiaxial tension / compression test, three-point bending test, and geometric dimension measurement.

[0049] In this embodiment, a multiaxial tensile-compression test is used to determine the stress-strain curve of the target marine organism, and a three-point bending test is used to determine the stiffness (tangential stiffness and normal stiffness) of the target marine organism. Geometric dimension measurements are used to obtain the average thickness or partition thickness of the target marine organism. If the thickness of the biological material is relatively uniform, the average thickness can be taken; if it is inconsistent, the average thickness of the partition can be taken as the diameter of the small particles.

[0050] Step S102: Initially set model parameters based on the obtained target biological parameters.

[0051] Step S2: Based on the various parameters of the target organism, calibrate the contact model parameters through simulation; set the diameter of the large particles according to the main body size of the target organism, set the diameter of the small particles according to the geometry of the target organism, calculate the particle coordinates based on the diameter of the small particles and the contact radius, compile the corresponding dynamic link library, replace the large particles with small particles and generate bonding bonds; generate the discrete element model of the target organism through the particles of the target organism shape and the particle bonding bonds.

[0052] Specifically, the parameters of the contact model are calibrated by simulation experiment based on the parameters of the target biomaterial, including model compilation and initial parameter setting; for parameter adjustment and calibration in simulation experiment: (1) The contact model is compiled into an executable script plugin for the simulation module using Visual Studio software C++ language, where the model parameters are used as interactive input parameters; (2) The contact model plugin is applied in the simulation module and the initially set model parameters are input; (3) The diameter of the large particle and the diameter of the small particle are set according to the size and thickness of the target biomaterial, and the particle coordinates are calculated based on the small particle diameter and contact radius and the corresponding dynamic link library file is compiled to replace the large particles with small particles and generate bonding bonds.

[0053] In this embodiment of the invention, calibrating the unidirectional coupling model based on the first deformation result includes the following steps:

[0054] Step S201: Compile the mathematical description of the contact model into an executable code plugin, and use the model parameters as interactive input parameters.

[0055] The contact model is described by the following formula:

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[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064] in, This represents the normal force on the particle at the current time step, i.e., the normal force on the particle at the current time step. This represents the standard adjustment factor. Represents the normal velocity of the particle. The normal stiffness of the particle bond is represented by A, where A represents the effective area for calculating particle stress. Indicates the time step. This represents the spring resistance adjustment coefficient, which can be increased accordingly when the target has a high degree of flexibility and obvious elastic behavior. The value of , The suggested value range is, but not limited to, 0~10. Indicates the equivalent spring tension coefficient. Represents the relative displacement components in the normal direction. This represents the equivalent damping coefficient. Indicates normal acceleration. This represents the tangential force on the particle at the current time step, i.e., the tangential force on the particle at the current time step. This indicates the tangential velocity of the particle. This represents the tangential stiffness of the particle bonding bond. This represents the relative displacement component in the tangential direction. Indicates tangential acceleration. This represents the normal torque on the particle at the time step infinitesimal element, i.e., the normal torque of the particle at the current time step. This represents the normal angular velocity of the particle. This represents the equivalent moment of inertia at the point of contact. This represents the tangential torque on the particle at the time step infinitesimal element, i.e., the tangential torque of the particle at the current time step. This represents the tangential angular velocity of the particle. This indicates the contact radius of the particles, i.e., the radius range within which adhesive bonds are formed. This represents the normal shear stress of the particle bonding bond. The stress intensity limit adjustment factor in the normal direction. This represents the tangential shear stress of the particle bonding bond. This represents the stress intensity limit adjustment factor in the tangential direction. These are all material flexibility parameter adjustment factors and model parameters. The flexibility parameter adjustment factors can be simulated and calibrated according to the flexibility of the target material and can be changed according to the softness of the target biological tissue. The stiffness can be selected according to the properties of the target biological material. The unit is N / m. 3 .

[0065] When the normal and tangential shear stresses exceed the predefined values, the bond is broken, and the target biological discrete element model ruptures.

[0066] Step S202: Apply the contact model plugin in the simulation module and input the initially set model parameters.

[0067] Step S203: Calculate the coordinates of the corresponding small particles based on the geometric dimensions of the target organism and write the particle replacement file.

[0068] First, the maximum geometric size of the target organism is used as the diameter of the large particle to create a discrete element large particle to be replaced, thereby generating the target organism swarm in the computational domain. Based on the main geometry of the target organism, such as its average thickness and outline, the coordinates and diameters of the small particles are calculated at certain intervals. There should be a certain gap between the small particles, but the gap should not make the distance between their centers greater than the contact radius; typically, this gap is 1-5 mm depending on the particle diameter. The coordinates of the small particles are relative to the center of the large particle. The diameter of the small particles is taken as the average thickness of the target organism or the average thickness of a partition. The generated large particles are replaced with a small particle swarm using the particle replacement external interface, and bonding bonds are generated between the small particles when the particle replacement takes effect.

[0069] Step S3: Construct the target biome.

[0070] The target marine organisms include: jellyfish, seaweed, krill, sea cucumber, and shrimp. In this embodiment of the invention, constructing a jellyfish biota includes the following steps:

[0071] Step S301: Determine the geometry of the jellyfish community, such as... Figures 2 to 4 As shown.

[0072] like Figure 3 As shown, the geometry of the jellyfish colony includes a hemispherical, umbrella-shaped thin structure and some slender tentacles. This embodiment focuses on studying the aforementioned geometry.

[0073] Step S302: Fit the geometry of the jellyfish body using spherical particles, including: setting the size distribution coefficient of the spherical particles according to the body size distribution range of the jellyfish biota. The initial position of the jellyfish in the fluid domain is random.

[0074] The size distribution coefficient of the spherical particles ranges from 1 to 2. For example, the umbrella diameter of an adult moon jellyfish is between 250 mm and 500 mm. If the diameter of the large particles used for the initial generation of a jellyfish colony is 250 mm, then when generating a jellyfish symbiont (i.e., a large number of jellyfish particle models with random spatial locations), setting the size distribution coefficient (i.e., the size distribution size factor) to a minimum of 1 and a maximum of 2 will result in the size of the shrimp models in the generated shrimp symbiont being randomly distributed between 250 mm × 1 and 25 mm × 2, i.e., between 250 and 500 mm. It should be understood that in other embodiments of the present invention, the size distribution coefficient range of the spherical particles can be set accordingly based on the actual size of the jellyfish.

[0075] The discrete element model of a jellyfish with a jellyfish shape and particle bonding is generated by particle replacement. It also includes generating bonding bonds with other small particles with damping and spring properties within the contact radius of small particles.

[0076] Specifically, to simplify the simulation model, the embodiments of this invention use spherical particles to fit the typical motion posture of a jellyfish: taking a 250mm long jellyfish body shape as a benchmark, several spheres are used to fit the thickness of the jellyfish's body cross-section. The sphere radii are set according to the actual size of the jellyfish body, thereby generating a simplified jellyfish particle model. Specifically, particle materials are created in EDEM with a material density of 1000kg / m³, Poisson's ratio of 0.45, collision loss coefficient of 0.8, elastic recovery coefficient of 0.2, and rolling friction coefficient of 0.02. Jellyfish particles are created based on the fitted data of a 250mm jellyfish body shape. Initial particle positions and orientations are generated in the fluid domain using a random function, and the volume generation method is changed to random, with a minimum volume factor of 1 and a maximum volume factor of 2. Preferably, the coordinate file of the fitted jellyfish particles is accessed through an external program. Figure 4 The diagram illustrates the use of spherical particles to fit jellyfish. It should be understood that large particles of a defined diameter can be generated in batches and then fed into a corresponding, pre-written file to replace smaller particles, thus generating jellyfish colonies more accurately.

[0077] Step S4: Simulation analysis of the interception of target organisms by the net; using the finite element / discrete element bidirectional coupled calculation method, the interception mechanism of the net on target marine organisms is simulated and analyzed.

[0078] The barrier net in this embodiment includes a planar net and a net-like structure. The planar net is characterized by its planar shape and the presence of uniformly distributed holes of the same size on its surface. The net-like structure is characterized by its pocket shape, with its overall geometric model being a trapezoidal frustum, and uniformly distributed holes of the same size on its five faces, with holes of varying sizes near the boundaries between the faces.

[0079] Furthermore, the bidirectional coupling method includes: a CFD and discrete element method bidirectional coupling. The barrier is a geometric solid model, and the fluid domain calculation model is obtained by Boolean subtraction with the water channel solid model. The fluid domain inlet is an open channel pressure inlet, and the free liquid level height corresponding to the real water channel is set. The fluid domain outlet is a normal pressure outlet. The specific preparation work is as follows: the shape of the barrier is imported into the water channel model to extract the fluid domain, and a static particle factory is created in the lower half of the volume on one side of the barrier inlet. The particle factory geometry is virtual, and the particles are selected from the jellyfish model particles created above. The total number of jellyfish is 5. Figure 5As shown. Automatic step size was turned off, the step size was set to 20%, the mesh size to 2.5R, the calculation time was 0.2 seconds, the result file was exported, and the initial time was set to 0 seconds. The exported EDEM file was opened, and EDEM listening mode was started. In Fluent, the computational domain mesh model was imported, the standard k-epsilon model and VOF model were set, and the open channel model was opened. The pressure open channel inlet was set, and the inlet free liquid level was half the height of the model. Subsequently, the interception mechanism of the barrier net on the target marine organisms was simulated and analyzed using a two-way coupling method of CFD and discrete element method. Figure 6 This is a schematic diagram illustrating the interception effect of a jellyfish swarm.

[0080] According to another aspect of the embodiments of this application, the present invention also provides a simulation device for constructing flexible biological and interception models based on particle contact. For example... Figure 7 As shown, the device includes: a parameter acquisition module, a model calibration module, an initial particle generation module, a particle replacement coordinate generation module, a marine biota construction module, a flexible bonding bond generation module, and an interception mechanism analysis module.

[0081] The parameter acquisition module determines various parameters of the target biomaterial based on experiments.

[0082] The parameter calibration module calibrates the contact model parameters based on various parameters of the target biomaterial through simulation experiments.

[0083] The initial particle generation module creates discrete element large particles to be replaced based on the maximum size of the target organism;

[0084] The particle replacement coordinate generation module calculates the coordinates of small particle groups at certain intervals based on the main geometry of the target organism.

[0085] The marine biota construction module uses a particle replacement external interface to replace the generated large particles with small particle clusters.

[0086] The flexible bonding bond generation module generates bonding bonds between small particles when particle replacement takes effect.

[0087] The interception mechanism analysis module uses a finite element / discrete element coupled calculation method to simulate and evaluate the interception effectiveness of the net against target marine organisms.

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing flexible biological models based on particle contact, characterized in that... Includes the following steps: Step S1: Obtain various parameters of the target organism, and preliminarily set the parameters of the biological model based on the obtained target organism parameters. The target organism is a flexible organism, and the various parameters include the stress-strain curve, stiffness and thickness of the flexible organism. Step S2: Based on the various parameters of the target organism, calibrate the contact model parameters through simulation; set the diameter of the large particles according to the main body size of the target organism, set the diameter of the small particles according to the geometry of the target organism, calculate the particle coordinates based on the diameter of the small particles and the contact radius, compile the corresponding dynamic link library, replace the large particles with small particles and generate bonding bonds; generate the discrete element model of the target organism through the particles of the target organism shape and the particle bonding bonds.

2. The method for constructing a flexible biological model based on particle contact according to claim 1, characterized in that: In step S2, a contact model of the target organism is constructed, and the contact model is calibrated based on the deformation results of the target organism. The contact model includes: The first result is obtained by multiplying the ratio of twice the particle tangential torque to the equivalent moment of inertia at the contact point by the particle contact radius. The second result is obtained by taking the ratio of the negative particle normal force to the effective area of ​​the particle stress calculation. The product of the sum of the first and second results and the normal stress intensity limit adjustment factor is greater than the normal shear stress of the particle bonding bond. The third result is obtained by multiplying the ratio of the particle normal torque to the equivalent moment of inertia at the contact point by the particle contact radius. The fourth result is obtained by taking the ratio of the negative particle tangential force to the effective area of ​​the particle stress calculation. The product of the sum of the third and fourth results and the tangential stress intensity limit adjustment factor is greater than the tangential shear stress of the particle bonding bond.

3. The method for constructing a flexible biological model based on particle contact according to claim 2, characterized in that: In step S2, the normal force of the particle is obtained by the normal force on the particle under the time step micro-element. The normal force on the particle under the time step micro-element is obtained by multiplying the normal relative displacement component and the equivalent spring tension coefficient, adding the product of the normal acceleration and the equivalent damping coefficient, multiplying the sum of the two by the spring resistance adjustment coefficient, and then adding the product of the particle normal velocity, the normal stiffness of the particle bonding bond, the effective area of ​​the particle stress calculation, the time step, and the negative conventional adjustment coefficient. The tangential force of the particle is obtained by the tangential force on the particle under the time step micro-element. The tangential force on the particle under the time step micro-element is obtained by multiplying the tangential relative displacement component and the equivalent spring tension coefficient, adding the product of the tangential acceleration and the equivalent damping coefficient, multiplying the sum of the two by the spring resistance adjustment coefficient, and then adding the product of the particle tangential velocity, the tangential stiffness of the particle bonding bond, the effective area of ​​the particle stress calculation, the time step, and the negative conventional adjustment coefficient. The normal torque of the particles is obtained by the normal torque on the particles under the time step micro-element. The normal torque on the particles under the time step micro-element is obtained by multiplying the negative normal angular velocity of the particles by the tangential stiffness of the particle bonding bond, the equivalent rotational inertia of the contact point, and the time step. The tangential torque of the particles is obtained by multiplying the tangential torque of the particles under the time step micro-element by multiplying the negative tangential angular velocity of the particles by the normal stiffness of the particle bonding bond, half of the equivalent rotational inertia of the contact point, and the time step. The effective area for calculating particle stress is obtained by multiplying the square of the particle's contact radius by π. The equivalent moment of inertia of the contact point is obtained by multiplying the fourth power of the contact radius of the particle by half of π.

4. The method for constructing a flexible biological model based on particle contact according to claim 2, characterized in that: When the normal and tangential shear stresses exceed the predefined values, the bond is broken, and the target biological discrete element model ruptures.

5. The method for constructing a flexible biological model based on particle contact according to claim 1, characterized in that: The geometry of the target organism includes average thickness or partition thickness. For target organisms with uniform thickness, the diameter of small particles is taken as the average thickness. For target organisms with inconsistent thickness, the average thickness of partitions is taken as the diameter of small particles.

6. The method for constructing a flexible biological model based on particle contact according to claim 1, characterized in that: The small particles have a certain gap between them, and the gap makes the distance between the center of the particles less than or equal to the contact radius.

7. The method for constructing a flexible biological model based on particle contact according to claim 1, characterized in that: The bonding bond is a bond that forms with other small particles within the contact radius of the small particles, exhibiting damping and spring-like properties.

8. A flexible biological model construction device based on particle contact, comprising: The module comprises a parameter acquisition module, a model calibration module, an initial particle generation module, a particle replacement coordinate generation module, a biosphere construction module, and a flexible bonding bond generation module, characterized in that: each module is executed sequentially according to any one of claims 1 to 7 of the flexible biological model construction method based on particle contact to construct the model of the target organism.

9. A method for constructing a flexible biological interception model based on particle contact, characterized in that... The process includes the following steps: Simulating interception using a biological model constructed according to the flexible biological model construction method based on particle contact as described in any one of claims 1 to 7, wherein the simulation interception includes the following steps: Step S3: Construct the target biota; based on the shape of the target organism, use spherical particles to fit the geometry of the target organism, and set the initial position of the target organism in the fluid domain; By replacing large particles with small particles, a set of discrete element models of the target organisms are generated, which have the shape of the target organisms and the particle bonding bonds. Step S4: Simulation analysis of the interception of the target organism by the barrier net; An interception device is constructed as a geometric solid model. The shape of the interception device is imported into the open channel solid model to extract the fluid domain. The inlet of the fluid domain is the open channel pressure inlet, and the outlet of the fluid domain is the ordinary pressure outlet. Model particles of the target organisms are introduced into the corresponding position of the liquid level on the inlet side of the interception device. The inlet pressure of the open channel and the free liquid level height at the inlet are set. The interception mechanism of the interception device on the target organisms is simulated and analyzed using the bidirectional coupling method of computational fluid dynamics and discrete element method.

10. A simulation device for constructing a flexible biological interception model based on particle contact, including an interception mechanism analysis module, characterized in that: The interception mechanism analysis module constructs an interception model according to the flexible biological interception model construction method based on particle contact as described in claim 9, and performs simulated interception on the target biological group.

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