Analysis device, analysis method, and analysis program

Abstract

To make it possible to express dynamic characteristics of an actual powder / granular material layer in more detail even when large particles are used.SOLUTION: An analysis device (1) for analyzing the behavior of multilayer particles by using a multilayer particle model defined by a plurality of particles that simulate a particle group at different densities, includes: an acquisition unit (10) that acquires physical property values of first particles that simulate the particle group at a first density and physical property values of second particles that simulate the particle group at a second density that is denser than the first density; and a first analysis unit (20) that calculates a contact force between the multilayer particles based on an amount of overlap between the first particles or the second particles, the physical property values of the first particles, and the physical property values of the second particles, and analyzes the behavior of the multilayer particles.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an analysis device, an analysis method, and an analysis program. [Background technology]

[0002] DEM (Discrete Element Method) is a calculation method for particle-like objects, in which an object or group of objects is represented as a spherical particle, etc., and the behavior of each particle is tracked. The closer the shape and size of the analyzed particles are to the actual particles, the more accurately the actual phenomenon can be represented.

[0003] Patent Document 1 discloses a method including a step of measuring particle attitude angles between analysis target particles and / or virtual particles, and solving equations of motion based on rotational motion for the analysis target particles and / or virtual particles to determine the behavior of each particle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2011-081530 Summary of the Invention [Problem to be solved by the invention]

[0005] When the scale of analysis becomes large, DEM simulates larger particle groups with a single large spherical particle to reduce the calculation load. In this case, it is not possible to express phenomena smaller than the analyzed particles. For example, the mechanical properties of a spherical particle simulating a densely packed particle group and a spherical particle simulating a loosely packed particle group are different, so it is not possible to accurately express both dense and loose states with the same particle.

[0006] Furthermore, spherical particles tend to be in a relatively dense state because they come into point contact with other objects. The range of void ratios that can be deposited stably is narrow and differs significantly from the range of void ratios in actual powder and granular layers. Furthermore, when large particles are used, it is difficult to express changes on a scale smaller than the particle, and there is a risk of the void ratio changing suddenly. Since void ratio is an important parameter that describes the interaction between granular materials and fluids (aerodynamic characteristics), accurate expression is necessary.

[0007] Such problems cannot be solved even if the discrete element method analysis simulation method described in Patent Document 1 is used.

[0008] One aspect of the present disclosure has been made in consideration of the above-mentioned conventional problems, and aims to provide a technology that can more precisely represent the mechanical properties of an actual powder / granular layer even when large particles are used. [Means for solving the problem]

[0009] In order to solve the above problems, an analysis device according to one embodiment of the present invention is an analysis device that analyzes the behavior of a multilayer particle using a multilayer particle model defined by a plurality of particles that simulate a particle group at different densities, and includes: an acquisition unit that acquires physical property values ​​of a first particle that simulates the particle group at a first density and physical property values ​​of a second particle that simulates the particle group at a second density that is denser than the first density; and a first analysis unit that calculates the contact force between the multilayer particles based on the amount of overlap between the first particles or the second particles, the physical property values ​​of the first particles, and the physical property values ​​of the second particles, and analyzes the behavior of the multilayer particle.

[0010] In order to solve the above-mentioned problems, an analysis method according to one embodiment of the present invention is an analysis method for analyzing the behavior of a multilayer particle using a multilayer particle model defined by a plurality of particles simulating a particle group at different densities, the analysis method including the steps of: acquiring physical property values ​​of a first particle simulating the particle group at a first density; and acquiring physical property values ​​of a second particle simulating the particle group at a second density denser than the first density; and calculating the contact force between the multilayer particles based on the amount of overlap between the first particles or the second particles, the physical property values ​​of the first particles, and the physical property values ​​of the second particles, to analyze the behavior of the multilayer particle. [Effects of the Invention]

[0011] According to one aspect of the present invention, even when large particles are used, it is possible to express the mechanical properties of an actual powder or granular material layer in more detail. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram illustrating an example of the configuration of an analysis device according to an embodiment of the present invention. [Figure 2] FIG. 1 is a diagram for explaining a multi-layer particle model. [Figure 3] FIG. 10 is a diagram for explaining contact forces between particles. [Figure 4] 10A and 10B are diagrams for explaining a contact force calculation method used in the analysis device according to the embodiment of the present invention. [Figure 5] 5 is a flowchart showing an example of a processing procedure in a first analysis unit of the analysis device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] <Example of analysis device configuration> 1 is a diagram showing an example of the configuration of an analysis device 1 according to an embodiment of the present invention. The analysis device 1 includes an acquisition unit 10, a first analysis unit 20, a second analysis unit 30, and a storage unit 40.

[0014] The first analysis unit 20 simulates the particle group to be analyzed with large particles and analyzes the behavior of the large particles using the discrete element method (DEM). The second analysis unit 30 calculates the porosity in the particle group from the position information of the large particles calculated by the first analysis unit 20, and analyzes the behavior of the seepage flow of the fluid containing the particle group based on the porosity.

[0015] First, a multilayer particle model used in the analysis device 1 according to this embodiment will be described. FIG. 2 is a diagram for explaining the multilayer particle model. FIG. 2 illustrates the case of soil and sand as an example of a particle group, but the particle group is not limited to this. Furthermore, as an example of a multilayer particle model, a case will be described in which the multilayer particle model is composed of three layers of spherical particles, but the particle shape may be any shape other than spherical. Furthermore, the number of layers constituting the multilayer particle model may be other than three.

[0016] As shown in Figure 2, the multi-layer particle model P is composed of three layers (P1, P2, P3). The outermost layer is made up of spherical particles that simulate a loosely packed particle group and will be called the first spherical particle P1. The middle layer is made up of spherical particles that simulate a tightly packed particle group and will be called the second spherical particle P2. The innermost layer is made up of spherical particles with a volume equivalent to a soil mass and no voids and will be called the third spherical particle P3. The first to third spherical particles that make up the three layers of spherical particles are examples of the first to third particles.

[0017] As shown in FIG. 2, the first to third spherical particles contain the same particle group, so the radius r1 of the first spherical particle P1 is the largest, the radius r2 of the second spherical particle P2 is the next largest, and the radius r3 of the third spherical particle P3 is the smallest.

[0018] As will be described later, the first analysis unit 20 mainly analyzes the behavior of the multilayer particles using the physical property values ​​of the first spherical particles P1 and the second spherical particles P2, while the second analysis unit 30 mainly analyzes the behavior of the seepage flow of the fluid containing the particle group using the radius r3 of the third spherical particles P3.

[0019] The acquisition unit 10 acquires the physical property values ​​of the first spherical particle P1 and the second spherical particle P2 included in the multi-layer particle model. These physical property values ​​include a spring constant, a viscous damping coefficient, a friction coefficient, a rotational resistance coefficient, etc. Furthermore, when a nonlinear spring model is used to calculate the contact force, Young's modulus, Poisson's ratio, etc. may also be included.

[0020] The first analysis unit 20 includes a contact determination unit 21, a physical property value determination unit 22, a contact force calculation unit 23, and a particle position update unit 24. The contact determination unit 21 determines whether or not the multi-layer particle models P are in contact with each other. For example, the contact determination unit 21 determines whether or not the multi-layer particle models P are in contact with each other based on position information of the centers of the multi-layer particle models P and the radius r1 of the first spherical particles P1.

[0021] When the contact determination unit 21 determines that the multi-layer particle models P are in contact with each other, the physical property value determination unit 22 determines the physical property value based on the overlap amount between the first spherical particles P1. Here, the overlap amount between the first spherical particles is defined as Δn ij The radius of the first spherical particle is r1, and the radius of the second spherical particle is r2. The overlap amount δn ij indicates the amount of overlap between multilayer particle i and multilayer particle j. The amount of overlap may be the amount of overlap between the second spherical particles P2.

[0022] The physical property value determining unit 22 determines the overlap amount Δn ij is smaller than the difference between the radius r1 of the first spherical particle P1 and the radius r2 of the second spherical particle P2, the physical property value of the first spherical particle P1 is selected as the physical property value. ij is equal to or greater than the difference between the radius r1 of the first spherical particle P1 and the radius r2 of the second spherical particle P2, the physical property value of the second spherical particle P2 is selected as the physical property value.

[0023] The contact force calculation unit 23 calculates the position information and velocity information of each multilayer particle by solving the equation of motion of the solid phase using the normal contact force, tangential contact force, non-contact force, etc. of each multilayer particle. The mass of the multilayer particle is m, the acceleration is a, and the contact force is F. C , the non-contact force F NC , particle-fluid interaction force F d , the body force F V Then, the equation of motion for the translational motion of the solid phase is as follows (Equation 1). Note that the contact force F C is the normal contact force F n and the tangential contact force F t The sum of (F n +F t ) and the non-contact force F NC These include liquid bridging forces, van der Waals forces, etc.

[0024]

number

[0025] Figure 3 is an example of a diagram for explaining the contact force between general particles, showing a linear spring-dashpot model. When particles come into contact (overlap), the contact force F C The contact force F C The normal component F n is a repulsive force, and the tangential component F t has the characteristic of acting as a frictional force. Note that when particles are in contact, it refers to a state in which the particles are beginning to overlap (are in contact). When particles overlap, it refers to a state in which the particles are virtually overlapping, and the amount of overlap is the amount of overlap.

[0026] Contact force F C The normal component F n Considering the Voigt model in which a spring and a dashpot are arranged in parallel, the tangential component F tuses a model in which a Voigt model and a slider are arranged in series. The spring represents the repulsive effect, the dashpot represents the energy dissipation effect, and the slider represents the sliding effect. In Figure 3, the spring constant in the normal direction is k n , the damping coefficient in the normal direction is η n , the tangential spring constant is k t , the tangential damping coefficient is η t , and the coefficient of friction is μ.

[0027] In addition, the normal contact force F n and the tangential contact force F t can be calculated using the following equations (2) and (3). Note that the velocity in the normal direction is v nij , the velocity in the tangential direction is v tij It states that:

[0028]

number

[0029] Also, the contact force F C For the calculation, a Maxwell model in which a spring and a dashpot are connected in series may be used, or a combination of the Voigt model and the Maxwell model may be used. Also, a Hooke model may be used as a linear spring, or a Hertz-Mindlin model may be used as a nonlinear spring.

[0030] The contact force calculation unit 23 basically calculates the contact force F using the model shown as an example in FIG. C is calculated, the difference between the radius r1 of the first spherical particle P1 and the radius r2 of the second spherical particle P2, and the overlap amount δn ij By comparing the physical property values ​​of the first spherical particle P1 and the second spherical particle P2, the contact force is calculated by selectively using the physical property values ​​of the first spherical particle P1 and the second spherical particle P2.

[0031] Specifically, the overlap amount δn ij <(r1-r2), the contact force F between the multilayer particles P is calculated using the following equation (Equation 4):C Also, the overlap amount δn ij If ≧(r1-r2), the contact force F between the multilayer particles P is calculated using the following equation (Equation 5). C Here, the physical property value of the first spherical particle P1 is α, the physical property value of the second spherical particle P2 is β, the contact force function of the first spherical particle P1 is f, and the contact force function of the second spherical particle P2 is g.

[0032] F C =αf (Formula 4) F C =αf+βg (Equation 5) FIG. 4 is a diagram for explaining a method for calculating the contact force when a linear spring is used. Note that FIG. 4 shows a case where there is no dashpot. Overlap amount Δn ij <(r1-r2), the contact force F between the multilayer particles P in the normal direction spring_n can be calculated using the following equation (Equation 6).

[0033] F spring_n =k n1 δ nij ...(Formula 6) In addition, the overlap amount δn ij If ≧(r1-r2), the contact force F between the multilayer particles P in the normal direction spring_n can be calculated using the following equation (Equation 7).

[0034] F spring_n =k n1 (r1-r2)+k n2 {δ nij -(r1-r2)} (Formula 7) In addition, in (Equation 7), k n1 Since (r1-r2) can be considered a constant, the overlap amount δn ij If ≧(r1-r2), the contact force F between the multilayer particles P in the normal direction spring_n It can be said that is determined only by the physical property values ​​of the second spherical particles P2.

[0035] The particle position update unit 24 calculates the external force acting on the multilayer particle P, and solves the equation of motion shown in Equation 1 using the contact force, external force, etc. acting on the multilayer particle P calculated by the contact force calculation unit 23 to calculate position information and velocity information of each multilayer particle P, and updates the position information and velocity of each multilayer particle P. The updated position information and velocity information of each multilayer particle P are stored in the memory unit 40.

[0036] The second analysis unit 30 analyzes the behavior of the seepage flow of a fluid containing particles, for example, using the Gidaspow model. In the Gidaspow model, the solid pressure term is expressed as a function of the porosity of the particle phase, and a large pressure gradient occurs as the porosity of the particle phase, i.e., the particle packing rate, approaches a set value in the momentum continuity equation. This indirectly models a state in which the particle packing rate does not exceed the set value by inhibiting the flow of the particle phase as the particle packing rate approaches the set value.

[0037] The second analysis unit 30 calculates the porosity of the particle group based on the positional information of each multilayer particle P obtained by the first analysis unit and the radius r3 of third spherical particles P3, which simulate the particle group as spherical particles without voids. The second analysis unit 30 can calculate the volume ratio occupied by the third spherical particles P3 in a given volume from the positional information of each multilayer particle P and the radius r3 of the third spherical particles P3, making it easy to calculate the porosity. The second analysis unit 30 analyzes the behavior of the seepage flow of the fluid containing the particle group by applying the calculated porosity to the Gidaspow model.

[0038] <Processing Procedure of First Analysis Unit 20> 5 is a flowchart showing an example of a processing procedure in the first analysis unit 20 of the analysis device 1 according to the embodiment of the present invention. First, the contact determination unit 21 determines whether or not a multilayer particle P will come into contact with another multilayer particle P by referring to the position information of the multilayer particle i stored in the storage unit 40 (S11). Note that i is a value from 1 to n and indicates a number for identifying each multilayer particle P.

[0039] When the contact determination unit 21 determines that the multilayer particle i is not in contact with another multilayer particle P (S11, No), the process proceeds to step S15. When the contact determination unit 21 determines that the multilayer particle i is in contact with another multilayer particle P (S11, Yes), the process proceeds to step S15. ij is calculated (S12).

[0040] Next, the physical property value determining unit 22 determines the overlap amount Δn ij is smaller than the difference between the radius r1 of the first spherical particle P1 and the radius r2 of the second spherical particle P2, the physical property value of the first spherical particle P1 is selected as the physical property value. ij is equal to or greater than the difference between the radius r1 of the first spherical particle P1 and the radius r2 of the second spherical particle P2, the physical property value of the second spherical particle P2 is selected as the physical property value (S13).

[0041] Next, the contact force calculation unit 23 calculates the contact force F using the physical property values ​​determined by the physical property value determination unit 22. C As described above, the contact force calculation unit 23 calculates the difference between the radius r1 of the first spherical particle P1 and the radius r2 of the second spherical particle P2 and the overlap amount Δn ij By comparing the physical property values ​​of the first spherical particle P1 and the second spherical particle P2, the contact force is calculated by selectively using the physical property values ​​of the first spherical particle P1 and the second spherical particle P2.

[0042] In step S15, the particle position update unit 24 calculates the external force acting on the multilayer particle i. Then, the particle position update unit 24 calculates the position information and velocity information of the multilayer particle i by solving the equation of motion of the solid phase using the normal contact force, tangential contact force, non-contact force, etc. of the multilayer particle i. Then, the particle position update unit 24 updates the position information and velocity information of the multilayer particle i stored in the memory unit 40 (S16).

[0043] Next, the particle position update unit 24 determines whether the calculation of the position information and velocity information of all multilayer particles has been completed (S17). If there are any multilayer particles for which the calculation of the position information and velocity information has not been completed (S17, No), i is updated to (i+1) (S18), and the process returns to step S11 and repeats the subsequent steps to calculate the position information and velocity information of the next multilayer particle i+1.

[0044] If there are no multilayer particles for which calculation of position information and velocity information has not been completed (S17, Yes), the particle position update unit 24 determines whether or not to advance time (S19). If time advances (S19, Yes), the particle position update unit 24 updates time t to (t + Δt) (S20), and returns to step S11 to repeat the subsequent processes, thereby calculating position information and velocity information of the multilayer particle P at time t + Δt. If time does not advance (S19, No), the first analysis unit 20 ends the process.

[0045] <Advantages of the analysis device 1 according to this embodiment> As described above, according to the analysis device 1 of this embodiment, the first analysis unit 20 calculates the overlap amount Δn ij The contact force between the multilayer particles P is calculated based on the physical property values ​​of the first spherical particles P1 and the physical property values ​​of the second spherical particles P2. In this way, by using the physical property values ​​of the first spherical particles P1 and the second spherical particles P2, the contact force between the multilayer particles P can be calculated with higher accuracy than in the past, and the mechanical properties of the actual powder / particle layer can be expressed in more detail.

[0046] The first analysis unit 20 also calculates the difference between the radius r1 of the first spherical particle P1 and the radius r2 of the second spherical particle P2 and the overlap amount Δn ij By comparing the radius r1 of the first spherical particle P1 with the radius r2 of the second spherical particle P2, the physical property values ​​of the first spherical particle P1 and the physical property values ​​of the second spherical particle P2 are selectively used. ij Since the contact force of the multilayer particles P can be calculated with high accuracy according to the above, the mechanical properties of the actual powder / particle layer can be expressed in more detail.

[0047] In addition, the first analyzing unit 20 calculates the overlap amount Δn ij When the overlap amount Δn is small, the contact force is calculated using the spring constant of the first spherical particle P1. ij If the overlap amount δn is large, the spring constant of the second spherical particle P2 is used to calculate the contact force. ij When the overlap amount is small, it indicates the contact behavior of coarse powder particles, and when the overlap amount is large, it indicates the contact behavior of dense powder particles, so it is possible to express the mechanical characteristics of an actual powder layer in more detail.

[0048] The second analysis unit 30 calculates the porosity of the particle group based on the position information of the multilayer particle P and the radius of the third spherical particle P3, which simulates the particle group as a spherical particle containing no voids. Therefore, the porosity of the particle group can be calculated with high accuracy, and the behavior of the seepage flow can be analyzed in more detail.

[0049] <Software implementation example> The functions of the analysis device 1 (hereinafter referred to as "device") can be realized by a program that causes a computer to function as the device, and a program that causes a computer to function as each control block of the device.

[0050] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The functions described in each of the above embodiments are realized by executing the program using the control device and storage device.

[0051] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0052] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of the control blocks can also be realized by, for example, a quantum computer.

[0053] 〔summary〕 The analysis device according to the first aspect of the present invention comprises: An analysis device that analyzes behavior of a multilayer particle using a multilayer particle model defined by a plurality of particles that simulate a particle group at different densities, comprising: an acquisition unit that acquires physical property values ​​of first particles that simulate a particle group at a first density and physical property values ​​of second particles that simulate the particle group at a second density that is denser than the first density; The apparatus is provided with a first analysis unit that calculates the contact force between the multilayer particles based on the amount of overlap between the first particles or the second particles, the physical property values ​​of the first particles, and the physical property values ​​of the second particles, and analyzes the behavior of the multilayer particles.

[0054] An analysis device according to a second aspect of the present invention is the analysis device according to the first aspect, the first particles and the second particles are first spherical particles and second spherical particles, respectively; The first analysis unit calculates the contact force between the multilayer particles by selectively using the physical property values ​​of the first spherical particles and the physical property values ​​of the second spherical particles by comparing the difference between the radius of the first spherical particles and the radius of the second spherical particles with the overlap amount.

[0055] An analysis device according to a third aspect of the present invention is the analysis device according to the second aspect, The first analysis unit If the overlap amount is smaller than the difference, calculating the contact force between the multilayer particles using the physical property values ​​of the first spherical particles; If the overlap amount is equal to or greater than the difference, the contact force between the multilayer particles is calculated using the physical property values ​​of the second spherical particles.

[0056] An analysis device according to a fourth aspect of the present invention is the analysis device according to the third aspect, The overlap amount between the first spherical particles is Δn ij , where r1 is the radius of the first spherical particle, r2 is the radius of the second spherical particle, α is the physical property value of the first spherical particle, β is the physical property value of the second spherical particle, f is the function of the contact force of the first spherical particle, and g is the function of the contact force of the second spherical particle, The first analysis unit The overlap amount δn ij is smaller than (r1-r2), the contact force F between the multilayer particles is calculated using the following formula (Formula 1): The overlap amount δn ij When the contact force F between the multilayer particles is equal to or greater than (r1-r2), the contact force F between the multilayer particles is calculated using the following formula (Formula 2): C Calculate.

[0057] F C =αf (Formula 2) F C =αf+βg (Equation 3) An analysis device according to a fifth aspect of the present invention is the analysis device according to the fourth aspect, The spring constant of the first spherical particle in the normal direction is k n1 , the spring coefficient of the second spherical particle in the normal direction is k n2 Then, The first analysis unit The overlap amount δn ij When is smaller than (r1-r2), the contact force F between the multilayer particles in the normal direction is calculated using the following formula (Formula 1): spring_n Calculate The overlap amount δn ij When r1 is equal to or greater than (r1-r2), the contact force F between the multilayer particles in the normal direction is calculated using the following formula (Formula 2): spring_n Calculate.

[0058] F spring_n =k n1 δ nij ...(Formula 4) F spring_n =k n1 (r1-r2)+kn2 {δ nij -(r1-r2)} (Formula 5) An analysis device according to a sixth aspect of the present invention is the analysis device according to any one of the first to fifth aspects, The analysis device further includes a second analysis unit that calculates the porosity of the particle group based on the position information of the multilayer particle obtained by the first analysis unit and the radius of third spherical particles that simulate the particle group as spherical particles containing no voids, and analyzes the behavior of the seepage flow of a fluid containing the particle group based on the porosity.

[0059] An analysis method according to a seventh aspect of the present invention includes: An analysis method for analyzing behavior of a multilayer particle using a multilayer particle model defined by a plurality of particles simulating a particle group at different densities, the method comprising: acquiring physical property values ​​of first particles simulating a particle group at a first density and physical property values ​​of second particles simulating the particle group at a second density denser than the first density; and a step of calculating the contact force between the multilayer particles based on the amount of overlap between the first particles or the second particles, the physical property values ​​of the first particles, and the physical property values ​​of the second particles, and analyzing the behavior of the multilayer particles.

[0060] An analysis program according to an eighth aspect of the present invention is an analysis program for causing a computer to function as the analysis device according to the first aspect, and causes the computer to function as the acquisition unit and the first analysis unit.

[0061] [Additional Notes] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0062] 1 Analysis device 10 Acquisition Department 20 1st Analysis Department 21 Contact determination section 22 Physical property determination section 23 Contact force calculation section 24 Particle position update section 30 2nd Analysis Department 40 Storage section

Claims

1. An analysis device that analyzes behavior of a multilayer particle using a multilayer particle model defined by a plurality of particles that simulate a particle group at different densities, comprising: an acquisition unit that acquires physical property values ​​of first particles that simulate a particle group at a first density and physical property values ​​of second particles that simulate the particle group at a second density that is denser than the first density; an analysis device comprising: a first analysis unit that calculates the contact force between the multilayer particles based on the amount of overlap between the first particles or the second particles, the physical properties of the first particles, and the physical properties of the second particles, and analyzes the behavior of the multilayer particles.

2. The first particles and the second particles are first spherical particles and second spherical particles, respectively, 2. The analysis device according to claim 1, wherein the first analysis unit selectively uses physical property values ​​of the first spherical particles and physical property values ​​of the second spherical particles by comparing the difference between the radius of the first spherical particles and the radius of the second spherical particles with the overlap amount, thereby calculating the contact force between the multilayer particles.

3. The first analysis unit If the overlap amount is smaller than the difference, calculating the contact force between the multilayer particles using the physical property values ​​of the first spherical particles; If the overlap amount is equal to or greater than the difference, the contact force between the multilayer particles is calculated using the physical property values ​​of the second spherical particles. The analysis device according to claim 2 .

4. The overlap amount between the first spherical particles is δn ｉｊ , the radius of the first spherical particle is r １ , the radius of the second spherical particle is r ２ , where α is the physical property value of the first spherical particle, β is the physical property value of the second spherical particle, f is the function of the contact force of the first spherical particle, and g is the function of the contact force of the second spherical particle, The first analysis unit The overlap amount δn ｉｊ (r １ -r ２ ), the contact force F between the multilayer particles is calculated using the following formula (Formula 4): Ｃ Calculate The overlap amount δn ｉｊ (r １ -r ２ ) or more, the contact force F between the multilayer particles is calculated using the following formula (Formula 5): Ｃ Calculate The analysis device according to claim 3 . F Ｃ =αf ・・・(Equation 4) F Ｃ =αf+βγ・・・(Expression 5)

5. The spring constant of the first spherical particle in the normal direction is k ｎ１ , the spring coefficient of the second spherical particle in the normal direction is k ｎ２ Then, The first analysis unit The overlap amount δn ｉｊ (r １ -r ２ ), the contact force F between the multilayer particles in the normal direction is calculated using the following formula (Formula 6): ｓｐｒｉｎｇ＿ｎ Calculate The overlap amount δn ｉｊ (r １ -r ２ ) or more, the contact force F between the multilayer particles in the normal direction is calculated using the following formula (Formula 7): ｓｐｒｉｎｇ＿ｎ Calculate The analysis device according to claim 4. F ｓｐｒｉｎｇ＿ｎ =k ｎ１ δ ｎij ... (Form 6) F ｓｐｒｉｎｇ＿ｎ = k ｎ１ (r １ - r ２ ) + k ｎ２ {δ ｎij - (r １ - r ２ )}... (Equation 7)

6. 6. The analysis device according to claim 1, further comprising a second analysis unit that calculates a porosity in the particle group based on the position information of the multilayer particle obtained by the first analysis unit and a radius of a third spherical particle that simulates the particle group as a spherical particle containing no voids, and analyzes behavior of a seepage flow of a fluid containing the particle group based on the porosity.

7. An analysis method for analyzing behavior of a multilayer particle using a multilayer particle model defined by a plurality of particles simulating a particle group at different densities, the method comprising: acquiring physical property values ​​of first particles simulating a particle group at a first density and physical property values ​​of second particles simulating the particle group at a second density denser than the first density; and calculating the contact force between the multilayer particles based on the amount of overlap between the first particles or the second particles, the physical property values ​​of the first particles, and the physical property values ​​of the second particles, and analyzing the behavior of the multilayer particles.

8. 2. An analysis program for causing a computer to function as the analysis device according to claim 1, the analysis program causing a computer to function as the acquisition unit and the first analysis unit.

Images