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

Abstract

The invention discloses a flexible biological and interception model construction method based on particle contact and a simulation device, and the method comprises the steps: carrying out the improved contact model parameter determination based on various parameters of a marine organism according to a discrete element particle contact model of a target marine organism; and the flexible contact model is combined with the particle replacement model to generate a flexible target marine organism discrete element model, a target marine organism group is constructed, and a finite element / discrete element coupling calculation method is utilized to perform simulation evaluation on the interception efficiency of the interception net on the target marine organisms. The discrete element particle contact model combines the characteristics of efficient calculation of discrete elements and flexibility of biological materials, can accurately and quickly simulate and obtain the results of deformation, breakage, escape and the like of marine organisms under the action of the blocking net, and analyzes the interaction mechanism of the blocking net and the marine organisms according to the results. According to the method, the blank of describing the biological material by discrete elements can be filled, and the research on the marine organism intercepting mechanism of the intercepting net is facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological and biological interception simulation, and particularly relates to a method for constructing a flexible biological and interception model based on particle contact and a simulation device. Background Art

[0002] Jellyfish is a common small aquatic organism, with characteristics such as high flexibility and easy breakage. The nuclear power plant intake channel cascade filtration system uses a trash rack to intercept jellyfish. Traditional trash rack designs rely on experience and simple hydrodynamic analysis. However, due to the small size and large quantity of jellyfish, and the fact that jellyfish are prone to deformation and breakage under the action of the trash rack and water flow, it is difficult to accurately predict the interception effect of the trash rack on jellyfish through conventional methods. Traditional methods such as hydrodynamic analysis are difficult to analyze the interaction mechanism between the trash rack and jellyfish, and there is a lack of a method for constructing a jellyfish flexible breakage model, which cannot provide strong guidance for the design of the nuclear power plant intake channel cascade filtration system. Therefore, determining the motion form of jellyfish under the action of water flow in the trash rack, and at the same time accurately simulating the motion of jellyfish in water flow and their interaction with the trash rack, is of great significance for improving the efficiency and accuracy of trash rack configuration design.

[0003] Current simulation technologies are mostly used for the fishing simulation of larger aquatic organisms, and there are relatively few simulation studies on small organisms such as jellyfish. During the simulation process, directly performing fluid-structure coupling analysis of the interaction between jellyfish and the trash rack cannot reflect the breakage problem of jellyfish, making it difficult to directly apply to the simulation of jellyfish biological groups, and the computational cost is high. At the same time, existing simulation technologies rarely conduct behavioral simulations of high-precision jellyfish model biological groups. Summary of the Invention

[0004] To solve the deficiencies of the prior art and achieve the purpose of high-precision simulation evaluation and interception of small flexible and easily damaged marine organisms, the present invention adopts the following technical solutions:

[0005] A method for constructing a flexible biological model based on particle contact, comprising the following steps:

[0006] Step S1: Obtain various parameters of the target organism, including stress-strain curve, stiffness, and thickness, and initially set the biological model parameters according to the obtained target organism parameters;

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

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

[0009] Multiply the ratio of twice the tangential moment of the particle to the equivalent moment of inertia of the contact point by the contact radius of the particle to obtain a first result. Take the negative ratio of the normal force of the particle to the effective area for calculating the particle stress as the second result, and make the product of the sum of the first result and the second result and the normal stress strength limit adjustment factor greater than the normal shear stress of the particle bonding bond;

[0010] Multiply the ratio of the normal moment of the particle to the equivalent moment of inertia of the contact point by the contact radius of the particle to obtain a third result. Take the negative ratio of the tangential force of the particle to the effective area for calculating the particle stress as the fourth result, and make the product of the sum of the third result and the fourth result and the tangential stress strength limit adjustment factor greater than the tangential shear stress of the particle bonding bond.

[0011] Further, the normal force of the particle is obtained from the normal force on the particle under the time-step microelement. The normal force on the particle under the time-step microelement is obtained by multiplying the product of 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 by the spring resistance adjustment coefficient, and then adding the product of the normal velocity of the particle, the normal stiffness of the particle bonding bond, the effective area for calculating the particle stress, the time step length, and the negative conventional adjustment coefficient;

[0012] The tangential force of the particle is obtained from the tangential force on the particle under the time-step microelement. The tangential force on the particle under the time-step microelement is obtained by multiplying the product of 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 by the spring resistance adjustment coefficient, and then adding the product of the tangential velocity of the particle, the tangential stiffness of the particle bonding bond, the effective area for calculating the particle stress, the time step length, and the negative conventional adjustment coefficient;

[0013] The normal moment of the particle is obtained from the normal moment on the particle under the time-step microelement. The normal moment on the particle under the time-step microelement is obtained by multiplying the negative normal angular velocity of the particle by the tangential stiffness of the particle bonding bond, the equivalent moment of inertia of the contact point, and the time step length;

[0014] The tangential moment of the particle is obtained from the tangential moment on the particle under the time-step microelement. The tangential moment on the particle under the time-step microelement is obtained by multiplying the negative tangential angular velocity of the particle by the normal stiffness of the particle bonding bond, half of the equivalent moment of inertia of the contact point, and the time step length;

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

[0017] The contact model formula is as follows:

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026] Among them, represents the normal force on the particle under the time step microelement, that is, the normal force of the particle at the current time step, represents the conventional adjustment coefficient, represents the normal velocity of the particle, represents the normal stiffness of the particle bonding bond, and A represents the effective area for particle stress calculation, represents the time step, represents the spring resistance adjustment coefficient, which can be increased accordingly when the target flexibility is high and the elastic behavior is obvious The value of The value range is recommended but not limited to 0 to 10, represents the equivalent spring tension coefficient, represents the relative displacement component in the normal direction, represents the equivalent damping coefficient, represents the normal acceleration, represents the tangential force on the particle under the time step microelement, that is, the tangential force of the particle at the current time step, represents the tangential velocity of the particle, represents the tangential stiffness of the particle bonding bond, represents the relative displacement component in the tangential direction, represents the tangential acceleration, represents the normal moment on the particle under the time step microelement, that is, the normal moment of the particle at the current time step, represents the normal angular velocity of the particle, represents the equivalent moment of inertia of the contact point, Represents the tangential moment on the particle under the time-step microelement, that is, the tangential moment of the particle at the current time step. Represents the tangential angular velocity of the particle. Represents the contact radius of the particle, that is, the radius range where the bonding bond is generated. Represents the normal shear stress of the particle bonding bond. Represents the adjustment factor of the normal stress strength limit. Represents the tangential shear stress of the particle bonding bond. Represents the adjustment factor of the tangential stress strength limit. All are material flexibility parameter adjustment factors and model parameters. The flexibility parameter adjustment factor can be calibrated by simulation 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, with the unit of N / m. 3 。

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

[0028] Furthermore, the geometry of the target biological includes the average thickness or the partition thickness. For the target biological with uniform thickness, the small particle diameter takes the average thickness; for the target biological with inconsistent thickness, the average thickness of the partition is taken as the diameter of the small particle.

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

[0030] Furthermore, the bonding bond generates a bonding bond with damping and spring characteristics 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 group construction module, and a flexible bonding bond generation module. Each module executes sequentially according to the flexible biological model construction method based on particle contact to construct the model of the target biological.

[0032] The flexible biological interception model construction method based on particle contact performs simulation interception according to the biological model constructed by the flexible biological model construction method based on particle contact. The simulation interception includes the following steps:

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

[0034] Step S4: Simulate and analyze the interception of the target organisms by the net; construct an interception device as a geometric entity model, import the shape of the interception device into the open-channel entity model, and obtain a fluid domain calculation model by performing a Boolean subtraction operation between the interception device and the open-channel entity model, thereby extracting 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; import the model particles of the target organism group at the corresponding position of the liquid level on the water inlet side of the interception device, set the open-channel inlet pressure and the height of the inlet free liquid level, and use the two-way 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 flexible biological interception model construction device based on particle contact includes an interception mechanism analysis module. The interception mechanism analysis module constructs an interception model according to the flexible biological interception model construction method based on particle contact, and performs a simulation interception on the target organism group.

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

[0037] The present invention constructs a discrete element particle model of marine organisms using a particle contact model. Through the calibrated marine organism model, various flexibilities and rigidities of marine organisms can be accurately and quickly simulated. On this basis, a target marine organism group model is constructed, and a finite element / discrete element two-way coupling calculation method is used to accurately analyze the action excitation of the net on intercepting marine organisms, realizing the high-precision construction of the discrete element particle model of marine organisms, and then analyzing the interaction mechanism of marine organism interception, thereby significantly improving the scientificity and reliability of net design and providing strong technical support for related engineering applications. Brief Description of the Drawings

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

[0039] Figure 2 is a diagram of a typical disaster-causing jellyfish in a nuclear power plant in the embodiment of the present invention.

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

[0041] Figure 4 is a diagram of a flexible particle model of jellyfish fitted with particles established in the embodiment of the present invention.

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

[0043] Figure 6 is a schematic diagram of the interception mechanism analysis and interception effect of a jellyfish group in the embodiment of the present invention.

[0044] Figure 7 Schematic structural diagram of the device in the embodiment of the present invention. Specific embodiments

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

[0046] To solve the problems in the prior art that it is difficult to obtain the deformation results of the fishing net and the existing simulation model cannot accurately simulate and evaluate the effect of the trash net on intercepting mysis shrimp, the present invention proposes a method for constructing a flexible biological and interception model based on particle contact, as Figure 1 shown, including the following steps:

[0047] Step S1: Obtain various parameters of the target organism, and initially set the biological model parameters according to the obtained target organism parameters; specifically, use physical experiments to determine various parameters of the target marine organism, including the following steps:

[0048] Step S101: Conduct physical experiments on the target organism to obtain parameters. The physical experiments include: multi-axial tensile / compression experiments, three-point bending tests, and geometric dimension measurements.

[0049] In this embodiment, a multi-axial tensile-compression experiment is used to measure the stress-strain curve of the target marine organism, a three-point bending test is used to measure the stiffness (tangential stiffness, normal stiffness) of the target marine organism, and geometric dimension measurements are used to obtain the average thickness or zoned thickness of the target marine organism. For biological materials with relatively uniform thickness, the average thickness can be taken, and for those with inconsistent thickness, the zoned average thickness can be taken as the diameter of small particles.

[0050] Step S102: Initially set the model parameters according to the obtained target organism parameters.

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

[0052] Specifically, the contact model parameters are calibrated by simulation experiments according to the various parameters of the target biological material, including model compilation and initial parameter setting; for the adjustment and calibration of simulation experiment parameters: (1) the contact model is compiled into an executable script plug-in for the simulation module using the C++ language of the visual studio software, in which the model parameters are used as interactive input parameters; (2) the contact model plug-in is applied to the simulation module and the model parameters preliminarily set are input; (3) the large particle diameter and the small particle diameter are set according to the size and thickness of the target biological body, 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 particle with the small particle and generate the bonding bond.

[0053] In an embodiment of the present invention, calibrating the one-way 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 plug-in, and use the model parameters as interactive input parameters.

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

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064] in, Indicates the normal force on the particle under the time step element, that is, the normal force of the particle at the current time step, represents the conventional adjustment coefficient, represents the normal velocity of the particle, represents the normal stiffness of the particle bonding bond, A represents the effective area for particle stress calculation, represents the time step, Indicates the spring resistance adjustment coefficient. When the target flexibility is high and the elastic behavior is obvious, it can be increased accordingly. The value of The value range is recommended but not limited to 0~10. represents the equivalent spring tension coefficient, represents the relative displacement component in the normal direction, represents the equivalent damping coefficient, represents the normal acceleration, represents the tangential force on the particle under the time step microelement, that is, the tangential force of the particle at the current time step, represents the tangential velocity of the particle, represents the tangential stiffness of the particle bonding bond, represents the relative displacement component in the tangential direction, represents the tangential acceleration, represents the normal moment on the particle under the time step microelement, that is, the normal moment of the particle at the current time step, represents the normal angular velocity of the particle, represents the equivalent moment of inertia at the contact point, represents the tangential moment on the particle under the time step microelement, that is, the tangential moment of the particle at the current time step, represents the tangential angular velocity of the particle, represents the contact radius of the particle, that is, the radius range where the bonding bond is generated, represents the normal shear stress of the particle bonding bond, represents the adjustment factor of the stress intensity limit in the normal direction, represents the tangential shear stress of the particle bonding bond, represents the adjustment factor of the stress intensity limit in the tangential direction. All are material flexibility parameter adjustment factors and model parameters. The flexibility parameter adjustment factor can be calibrated by simulation 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 performance of the target biological material, with the unit of N / m 3 .

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

[0066] Step S202: Apply the contact model plug-in in the simulation module and input the preliminarily set model parameters.

[0067] Step S203: Calculate the coordinates of the corresponding small particles according to the geometric size of the target organism and write the particle replacement file.

[0068] First, use the maximum geometric size of the target organism as the diameter of the large particles to create discrete element large particles to be replaced as a whole, so as to generate a target organism group in the computational domain. According to the main geometric shapes such as the average thickness size profile of the target organism, calculate the coordinates and diameters of the small particles at a certain interval. There should be a certain gap between the small particles, but the gap should not make the center distance of the spheres greater than the contact radius. Usually, according to the diameter of the particles, it can be taken as 1-5 mm. The coordinates of the small particles are the relative coordinates with respect 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 the partition. In order to use the particles to replace the external interface, replace the generated large particles with a group of small particles, and generate bonding bonds between the small particles when the particle replacement takes effect.

[0069] Step S3: Construct a target organism group.

[0070] The target marine organisms include: jellyfish, seaweed, mysid shrimp, sea cucumber, and pen tip cap snail. In the embodiments of the present invention, constructing a jellyfish organism group includes the following steps:

[0071] Step S301: Determine the geometric shape of the jellyfish organism group, as Figures 2 to 4 shown.

[0072] As Figure 3 shown, the geometric shape of the jellyfish colony includes a hemispherical umbrella-shaped thin surface structure and some slender tentacles. In this embodiment, the above geometric shape is studied.

[0073] Step S302: Fit the geometric shape of the jellyfish body with spherical particles, including: setting the size distribution coefficient of the spherical particles according to the body size distribution range of the jellyfish organism group. The initial position of the jellyfish in the fluid domain is a random position.

[0074] The range of the size distribution coefficient of the spherical particles is 1-2. For example, the umbrella diameter of the adult Aurelia aurita is between 250 mm and 500 mm. If the diameter of the large particles used for the initial generation of the jellyfish colony is 250 mm, then when generating the jellyfish organism group (i.e., a large number of jellyfish particle models at random spatial positions), set the size distribution coefficient (i.e., the size distribution size factor) to a minimum of 1 times and a maximum of 2 times. Then the size of the mysid shrimp models in the generated mysid shrimp organism group is randomly distributed between 250 mm × 1 and 25 mm × 2, that is, between 250 and 500 mm. It should be understood that in other embodiments of the present invention, the range of the size distribution coefficient of the spherical particles can be set accordingly according to the actual size of the jellyfish.

[0075] Generating a jellyfish discrete element model with a jellyfish shape and particle bonding bonds through particle replacement further includes: generating bonding bonds with damping and spring characteristics with other small particles within the contact radius of the small particles.

[0076] Specifically, in order to simplify the simulation model, spherical particles are used in the embodiment of the present invention to fit the typical movement posture of jellyfish: taking the 250mm long jellyfish body as a benchmark, several spheres are used to fit the thickness of the jellyfish's body cross-section, and the corresponding sphere radius is set according to the actual size of the jellyfish body, thereby generating a simplified jellyfish particle model. Specifically, a granular material is created in EDEM with a material density of 1000kg / m³, a Poisson's ratio of 0.45, a collision loss coefficient of 0.8, an elastic recovery coefficient of 0.2, and a rolling friction coefficient of 0.02. Jellyfish particles are created based on the 250mm jellyfish body fitting data, and the initial particle position and particle orientation are generated in the fluid domain according to a random function, and the volume generation method is changed to random, with a minimum volume coefficient of 1 and a maximum volume coefficient of 2. Preferably, the small particle coordinate file for fitting the jellyfish is accessed through external writing. As Figure 4 A schematic diagram of using spherical particles to fit jellyfish is shown in FIG. It should be understood that large particles of a certain diameter can be generated in batches and connected to the corresponding small particle replacement file to more accurately generate jellyfish groups.

[0077] Step S4: Simulate and analyze the interception of the target organisms by the blocking net; use the finite element / discrete element bidirectional coupling calculation method to simulate and analyze the interception mechanism of the blocking net on the target marine organisms.

[0078] The blocking nets in this embodiment include flat nets and net bag nets. Flat nets are characterized by a flat surface with uniformly sized, evenly distributed holes. Net bag nets are characterized by a bag-shaped net with an overall trapezoidal prism geometry, uniformly sized holes evenly distributed across the five faces, and holes of varying sizes near the intersections of the faces.

[0079] Furthermore, the bidirectional coupling method includes: a bidirectional coupling method of CFD and discrete element. The barrier is a geometric entity model, and the fluid domain calculation model is obtained by Boolean difference with the canal entity model. The fluid domain inlet is an open channel pressure inlet, and the free liquid surface height corresponding to the real canal is set, and the fluid domain outlet is an ordinary pressure outlet. The specific preparations are as follows: import the barrier shape into the canal model to extract the fluid domain, and create a static particle factory in the lower half of the volume on one side of the barrier inlet. The particle factory geometry is virtual, and the particles select the jellyfish model particles created above. The total number of jellyfish is 5, as shown in the following figure. Figure 5As shown in the figure, turn off the automatic step size, set the step size to 20%, set the grid size to 2.5R, calculate for 0.2 seconds, export the result file, and set the initial time to 0 seconds. Open the exported EDEM file and start the EDEM listening mode. In Fluent, import the computational domain grid model, set the standard k-epsilon model and VOF model, open the open-channel model, set the pressure open-channel inlet, and the free liquid level at the inlet is half of the height of the model. Subsequently, use the CFD-discrete element bidirectional coupling method to simulate and analyze the interception mechanism of the barrier net on the target marine organisms. Figure 6 Schematic diagram of the interception effect of the jellyfish swarm.

[0080] According to another aspect of the embodiments of the present application, the present invention also provides a simulation device for constructing a flexible biological and interception model based on particle contact. As Figure 7 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 organism group 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 biological material according to experiments;

[0082] The parameter calibration module calibrates the contact model parameters with simulation experiments according to the various parameters of the target biological material;

[0083] The initial particle generation module creates large discrete element particles to be replaced as a whole according to the maximum size of the target organism;

[0084] The particle replacement coordinate generation module calculates the coordinates of a small particle group at a certain interval according to the main geometric shape of the target organism;

[0085] The marine organism group construction module uses the particle replacement external interface to replace the generated large particles with a small particle group;

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

[0087] The interception mechanism analysis module uses the finite element / discrete element coupling calculation method to simulate and evaluate the interception efficiency of the barrier net on the target marine organisms.

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing a flexible biological model based on particle contact, characterized in that It includes the following steps: Step S1: Obtain various parameters of the target organism, and preliminarily set the biological model parameters according to the obtained target organism parameters; Step S2: Simulate and calibrate the contact model parameters according to the various parameters of the target organism; set the large particle diameter according to the main body size of the target organism, set the small particle diameter according to the geometric shape of the target organism, calculate the particle coordinates based on the small particle diameter and the contact radius, and compile the corresponding dynamic link library, replace the large particles with small particles and generate bonding bonds; generate a discrete element model of the target organism through the particles and particle bonding bonds of the target organism shape.

2. The method for constructing a flexible biological model based on particle contact according to claim 1, wherein: In the step S2, a contact model of the target organism is constructed, and the contact model is calibrated based on the deformation result of the target organism. The contact model includes: Multiply the ratio of twice the tangential moment of the particle to the equivalent moment of inertia at the contact point by the particle contact radius to obtain a first result, take the ratio of the negative normal force of the particle to the effective area calculated by the particle stress as a second result, and make the product of the sum of the first result and the second result and the normal stress strength limit adjustment factor greater than the normal shear stress of the particle bonding bond; Multiply the ratio of the normal moment of the particle to the equivalent moment of inertia at the contact point by the particle contact radius to obtain a third result, take the ratio of the negative tangential force of the particle to the effective area calculated by the particle stress as a fourth result, and make the product of the sum of the third result and the fourth result and the tangential stress strength limit adjustment factor 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, wherein: In the step S2, the normal force of the particle is obtained through the normal force on the particle in the time step microelement. The normal force on the particle in the time step microelement is obtained by multiplying the product of 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 by the spring resistance adjustment coefficient, and then adding the product of the normal velocity of the particle, the normal stiffness of the particle bonding bond, the effective area calculated by the particle stress, the time step length, and the negative conventional adjustment coefficient; The tangential force of the particle is obtained through the tangential force on the particle in the time step microelement. The tangential force on the particle in the time step microelement is obtained by multiplying the product of 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 by the spring resistance adjustment coefficient, and then adding the product of the tangential velocity of the particle, the tangential stiffness of the particle bonding bond, the effective area calculated by the particle stress, the time step length, and the negative conventional adjustment coefficient; The normal moment of the particle is obtained through the normal moment on the particle in the time step microelement. The normal moment on the particle in the time step microelement is obtained by multiplying the negative normal angular velocity of the particle by the tangential stiffness of the particle bonding bond, the equivalent moment of inertia at the contact point, and the time step length; The tangential moment of the particle is obtained through the tangential moment on the particle in the time step microelement. The tangential moment on the particle in the time step microelement is obtained by multiplying the negative tangential angular velocity of the particle by the normal stiffness of the particle bonding bond, half of the equivalent moment of inertia at the contact point, and the time step length; The effective area calculated by the particle stress is obtained by multiplying the square of the contact radius of the particle 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 one-half of π.

4. The method for constructing a flexible biological model based on particle contact according to claim 2, wherein: When the normal and tangential shear stresses exceed the predefined values, the bonding 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, wherein: The geometry of the target organism includes the average thickness or partition thickness. For the target organism with uniform thickness, the average thickness is taken as the diameter of the small particles. For the target organism with non-uniform thickness, the average thickness of the partition is taken as the diameter of the small particles.

6. The method for constructing a flexible biological model based on particle contact according to claim 1, wherein: There is a certain gap between the small particles, and the gap makes the center-to-center distance 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, wherein: The bonding bond generates a bonding bond with damping and spring characteristics with other small particles within the contact radius range of the small particles.

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

9. Method for constructing a flexible biological interception model based on particle contact, characterized in that It includes the following steps: performing simulation interception on the biological model constructed according to the flexible biological model construction method based on particle contact described in any one of claims 1 to 7, and the simulation interception includes the following steps: Step S3: Construct a target biological population; 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; Generate a discrete element model of a group of target organisms with the shape of the target organism and particle bonding bonds by replacing large particles with small particles; Step S4: Perform simulation analysis on the interception of the target organism by the net; Construct an interception device as a geometric solid model, import the shape of the interception device 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; Import the model particles of the target biological population at the corresponding position of the liquid level on the water inlet side of the interception device, set the open channel inlet pressure and the inlet free liquid level height, and use the two-way coupling method of computational fluid dynamics and discrete element to perform simulation analysis on the interception mechanism of the interception device on the target organism.

10. A 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 described in claim 9 and performs simulation interception on the target biological population.

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