A method for calculating the load of a mining dump truck

Abstract

This invention provides a method for calculating the load of mining dump trucks. It establishes the interaction relationship between two particles resting at the corner of the cargo box and the side and bottom plates of the cargo box, obtaining the forces exerted on the particles by the side and bottom plates. It provides strong and weak frictional solutions, extending the interaction relationship to the entire cargo box material, obtaining the forces exerted on the material by the side and bottom plates, and providing a critical value for the comprehensive friction coefficient. It establishes a multi-point support model and a porosity model for the material particles, identifies the relationship between the particle stacking angle and the number of particle support points, and combines the actual cargo box loading rate with the porosity model to establish the relationship between the loading rate and the number of particle support points. It determines a suitable multi-point support model for particles, establishes the relationship between the finite element mesh size and the material particle size, and establishes the force distribution relationship between the side and bottom plates of the cargo box on the material particles based on the finite element mesh. This invention can effectively cover all road conditions in the actual operating environment of mining dump trucks.

Description

Technical Field

[0001] This invention relates to the field of mining dump truck cargo box technology, specifically a method for calculating the side load of a mining dump truck cargo box. Background Technology

[0002] Mining dump trucks are key equipment in open-pit mining and large-scale earthwork construction, characterized by their high load capacity and high work efficiency. In their actual operating environment, they frequently face harsh and complex mine conditions. Under these conditions, mining dump trucks must endure complex working situations such as fully loaded uphill and downhill driving, rough road surfaces, sharp turns, braking, obstacle crossing, and sinking. The cargo box, as the direct working component of the mining dump truck, constantly bears the enormous weight of the material, the impact force during loading, and the friction force during unloading. Accurately determining the true stress on the side and bottom plates of the cargo box after loading is crucial for dump truck cargo box product design, finite element simulation load application, and structural strength verification.

[0003] The applicant found that existing publicly available literature lacks algorithms specifically developed for the stress on the side and bottom plates of dump truck cargo boxes after loading materials. In specific strength verification and finite element simulation calculations, traditional theories of Rankine and Coulomb soil are often simply applied. This transfer of calculation models lacks both theoretical derivation and practical verification. Specifically, this application of traditional earth pressure theory has at least the following problems in practical applications:

[0004] 1) Different materials. Rankine and Coulomb theories study dense soil materials, assuming the soil layer as a continuous medium in their theoretical derivations. However, mining dump trucks load loose materials such as gravel, silt, and sand, either individually or in mixtures, which cannot be treated as a continuous medium.

[0005] 2) The wall surfaces are different. Rankine soil and Coulomb soil theories study the forces exerted by dense soil materials on the back of the wall, both assuming the back of the wall is rigid. However, in reality, the side panels and bottom plate of the cargo box are welded from steel plates, making them flexible bodies.

[0006] 3) Different wall stress modes. Rankine soil theory assumes that the back of the wall is an ideal smooth surface, but in reality, there is a certain friction between the side plate of the cargo box and the material; although Coulomb soil theory assumes that the wall surface is rough, it requires that the soil layer fracture and slip surface be planar and must pass through the heel of the wall. The boundary conditions of the theory are more stringent and do not match the actual working conditions.

[0007] 4) Narrow research scope. Applying the Rankine and Coulomb soil theories only yields the force exerted by the material on the side wall behind the wall, because it assumes the soil layer is a semi-infinite mass, making it impossible to obtain the force on the bottom layer. Therefore, these two theories cannot be used to obtain the force exerted by the material on the bottom plate of the cargo box.

[0008] Existing literature, besides indiscriminately applying Rankine or Coulomb soil theories, leading to inconsistent boundaries and inaccurate stress on cargo box side panels, suffers from a more serious problem: these theories lack theoretical support for the specific distribution of forces acting on the cargo box bottom and side panel loads. Authors simply assume hydrostatic pressure as the load distribution pattern, or even directly apply material gravity to the cargo box bottom, practices that are severely inconsistent with reality. In addition to applying forces to the cargo box in finite element models, some literature crudely constructs the material as a continuous entity, attempting to simulate the interaction between the material and the wall using simple bonded contact and commercial software. However, the material is discontinuous, loose, and a complex mixture. Its material parameters, constitutive relations, complex contact with the cargo box, and inter-particle interactions cannot be realistically modeled, making the calculation results obtained in this way unconvincing.

[0009] For the reasons mentioned above, this invention creatively proposes a method for calculating the load on the side plate and bottom plate of the cargo box of a mining dump truck. The theoretical establishment process fully considers the connection with subsequent finite element modeling calculations. Through strong correlation with the finite element mesh, it facilitates subsequent simulation calculations and has strong practicality, filling a technical gap in this field. Summary of the Invention

[0010] To address the problems existing in the prior art, this invention provides a method for calculating the load of mining dump trucks, which can effectively cover all road conditions in the actual operating environment of mining dump trucks.

[0011] The technical solution adopted in this invention is a method for calculating the load of a mining dump truck, comprising the following steps:

[0012] S1: Establish the interaction relationship between the two particles leaning against the corner of the cargo box and the side plate and bottom plate of the cargo box, obtain the force exerted by the side plate and bottom plate of the cargo box on the particles, and give the solutions for strong and weak friction.

[0013] S2: Extend the interaction relationship established in step S1 to the entire cargo box material to obtain the force exerted on the material by the side plate and bottom plate of the cargo box.

[0014] S3: Based on the numerical relationship between the strong and weak forms of friction established in step S1, give the critical value of the comprehensive friction coefficient.

[0015] S4: Establish a multi-point support model and porosity model for material particles, and identify the relationship between particle stacking angle and the number of particle support points;

[0016] S5: Combine the actual cargo loading rate with the porosity model to establish the relationship between the loading rate and the number of particle support points, and determine a suitable multi-point support model for particles;

[0017] S6: Establish the relationship between finite element mesh size and material particle size;

[0018] S7: Establish the force distribution relationship between the side plates and bottom plate of the cargo compartment and the material particles based on the finite element mesh.

[0019] Preferably, the specific method of step S1 is as follows:

[0020] Select two particles i and j located in the corner of the cargo box. Particle i is supported by the side panel of the cargo box and particle j, while particle j is supported by the bottom panel of the cargo box and particle i. The external force acting on particle i is its own weight M. i g. Comprehensive frictional force f i Normal force N on the side panel of the cargo box i The external force acting on particle j is its own weight M. j g. Comprehensive frictional force f j Normal force N on the cargo box floor j The angle between the intangents of particles i and j and the floor of the cargo box is θ. k The comprehensive frictional force *f* takes into account both the sliding friction between the material particles and the cargo box wall, as well as the interlocking friction between the particles. Its expression is:

[0021] f=(μ 滑动 +μ 咬合 )N (1)

[0022] μ = μ 滑动 +μ 咬合 (2)

[0023] In the formula, N is the normal force exerted by the cargo box wall on the particles, μ is the comprehensive friction coefficient, and μ 滑动 μ is the coefficient of sliding friction. 咬合 The coefficient of interlocking friction;

[0024] When the combined frictional force dominates, the normal force N exerted by the side panel of the cargo box on the particles is... i The normal force N exerted by the cargo box floor on the particles j The expression for the frictional force, i.e., the formal solution, is:

[0025]

[0026] When the overall frictional force is secondary, the normal force N exerted by the side panel of the cargo box on the particles is... i The normal force N exerted by the cargo box floor on the particles j The expression for friction, i.e., the weak form solution, is:

[0027]

[0028] Preferably, step S2 specifically comprises:

[0029] Given the following two assumptions:

[0030] 1) Traverse all paired particles in the box, their θ k It follows a normal distribution in the open interval (0°, 90°);

[0031] 2) The particle size of the material inside the cargo compartment follows a normal distribution within a certain range; then...

[0032] Use N s The normal force exerted by one side panel of the cargo compartment on the material, in N. b The normal force exerted by the cargo box floor on the material can be represented by the following frictional force:

[0033]

[0034] The weak form of the frictional force solution is:

[0035]

[0036] In equations (5) to (6), i, j, and k are indicator variables for the labeled particle mass and the included angle sequence, respectively, and n p Let G be the total number of material particles and G be the weight of the material.

[0037] The preferred method for calculating the critical value of the comprehensive friction coefficient is as follows:

[0038] make We can obtain:

[0039]

[0040] At this point, the overall friction coefficient is at a critical value, and this critical overall friction coefficient value is denoted as μ. c When μ > μ c When the frictional force is strong, the calculation method adopts the solution of equation (5); when μ < μ c When, the calculation method adopts the weak form solution of friction force in equation (6).

[0041] Preferably, step S4 specifically comprises:

[0042] Let N represent the number of points in the multi-point support model of particles, n represent any positive integer, m represent the number of particles in each layer, and d represent the particle size (diameter); B i C i α i δ i h i (i = 2, 3, 4, ..., n) represent the center-to-center distance between the two ends of the transverse particles, the center-to-center distance between the two ends of the longitudinal particles, the stacking angle of the interlayer particles, the porosity of the material, and the interlayer height of the particles, respectively; since there is no case where all particles in the actual material have the same particle size, n is at least 2;

[0043] For an n-point support model, where n≥2, we have:

[0044]

[0045] Preferably, step S5 specifically includes:

[0046] S51: The cargo compartments are filled in a flat-stacking manner, and the loading volume M of the material is measured using a weighing system. l ;

[0047] S52: The cargo loading rate η can be written as:

[0048]

[0049] In the formula, ρ is the density of the ore material without considering porosity, and V is the volume of the material.

[0050] S53: Let η = δ n Calculate the suitable value for the number of points n in the multi-point contact model:

[0051]

[0052] In the formula, the operator CI() represents the most recent integer.

[0053] Preferably, step S6 specifically comprises:

[0054] The particle size of the multi-point support model for material particles is set according to the finite element mesh size as follows:

[0055] S61: Specify the finite element mesh type and size; the side panels and floor of the cargo box shall adopt a uniform quadrilateral mesh configuration and mesh size s.

[0056] S62: For multi-point support models with consistent particle size, the centroid of the material particles must be aligned with the mesh nodes layer by layer, and the particle size d must meet the following requirements:

[0057] s=d·sinα n (11)

[0058] S63: After the finite element mesh is strongly correlated with the multi-point contact model, the number of particles m in each layer in step S5 is written as:

[0059]

[0060] In the formula, B represents the width of the cargo compartment opening.

[0061] Preferably, step S7 specifically includes:

[0062] S71: Establish an n-point contact model for the material according to steps S5 and S6, with the material particles stacked at an angle α as specified in equation (8). n Stacking;

[0063] S72: Create an n1-order vector T x (n1) The proportional relationship of the forces on each layer of the storage compartment side panel, n1 and the vector values ​​T of each layer. x (u) is:

[0064]

[0065] In the formula, h is the depth of the cargo compartment cavity. c b is the critical height for particle stacking. n This represents the number of particle layers at the critical height.

[0066]

[0067] In the formula, u is the spatial location sorting code from top to bottom;

[0068] S73: Create an n² vector T y (n2) The proportional relationship of the forces on the floor of the storage compartment, n2 and the vector values ​​T of each layer. y (v) is:

[0069]

[0070] In the formula, v is the spatial position sorting code from left to right, L(v) is the left-order positioning state variable, and R(v) is the right-order positioning state variable;

[0071]

[0072] The beneficial effects of this invention are as follows: By establishing a scientific theoretical model and calculation well through strong correlation with the finite element mesh, this invention opens up the connection between the theoretical model and subsequent finite element simulation calculation, which facilitates the application of subsequent loads and has strong creativity and practicality. Attached Figure Description

[0073] Figure 1 For the load calculation model of the cargo box side panels and floor;

[0074] Figure 2 This is a graph showing the relationship between the force index of the cargo box side panels and the comprehensive friction coefficient.

[0075] Figure 3 A two-point support model for material particles;

[0076] Figure 4 A three-point support model for material particles;

[0077] Figure 5A four-point support model for material particles;

[0078] Figure 6 This is a non-uniform load distribution mode for a two-point support model when the base plate size is large.

[0079] Figure 7 This is a nonlinear load distribution mode for a two-point support model when the side plate size is large. Detailed Implementation

[0080] To further illustrate the details and advantages of the technical solution of the present invention, the following description is provided in conjunction with the accompanying drawings.

[0081] S1: Establish the interaction relationship between the two particles leaning against the corner of the cargo box and the side plate and bottom plate of the cargo box, obtain the force exerted by the side plate and bottom plate of the cargo box on the particles, and give the solutions for strong and weak friction.

[0082] like Figure 1 As shown, at the corner of the container where the material is loaded, two particles, i and j, of different sizes can always be found. Particle i is supported by the side panel of the container and particle j, while particle j is supported by the bottom panel of the container and particle i. Due to the non-smooth wall surface, the external force on particle i is its own weight M. i g. Comprehensive frictional force f i Normal force N on the side panel of the cargo box i The external force acting on particle j is its own weight M. j g. Comprehensive frictional force f j Normal force N on the cargo box floor j The angle between the intangents of particles i and j and the floor of the cargo box is θ. k The comprehensive frictional force *f* takes into account both the sliding friction between the material particles and the cargo box wall, as well as the interlocking friction between the particles. Its expression is:

[0083] f=(μ 滑动 +μ 咬合 )N (1)

[0084] μ = μ 滑动 +μ 咬合 (2)

[0085] In the formula, N is the normal force exerted by the cargo box wall on the particles, μ is the comprehensive friction coefficient, and μ 滑动 μ is the coefficient of sliding friction. 咬合 The coefficient of friction is the interlocking friction coefficient.

[0086] When the combined frictional force dominates, the normal force N exerted by the side panel of the cargo box on the particles is... i The normal force N exerted by the cargo box floor on the particles j The expression for the frictional force, i.e., the formal solution, is:

[0087]

[0088] (3) The strong form solution in the formula is applicable to situations where the overall frictional force is large, the wall surface is rough, the particle size distribution is uniform, the porosity of the loosely packed material is small, and the effective contact area with the wall surface is large.

[0089] When the overall frictional force is secondary, the normal force N exerted by the side panel of the cargo box on the particles is... i The normal force N exerted by the cargo box floor on the particles j The expression for friction, i.e., the weak form solution, is:

[0090]

[0091] S2: Extend the interaction relationship established in step S1 to the entire cargo box material to obtain the force exerted on the material by the side plate and bottom plate of the cargo box.

[0092] Given the following two assumptions:

[0093] 1) Traverse all paired particles in the box, their θ k It follows a normal distribution in the open interval (0°, 90°);

[0094] 2) The particle size of the material particles in the cargo compartment is normally distributed within a certain range.

[0095] Then use N s The normal force exerted by one side panel of the cargo compartment on the material, in N. b The normal force exerted by the cargo box floor on the material can be represented by the following frictional force:

[0096]

[0097] The weak form of the frictional force solution is:

[0098]

[0099] In equations (5) to (6), i, j, and k are indicator variables for the particle mass and included angle sequence, and n p Let G be the total number of material particles and G be the weight of the material.

[0100] S3: Based on the numerical relationship between the strong and weak forms of friction, the critical value of the comprehensive friction coefficient is given;

[0101] Critical value of comprehensive friction coefficient μ c The method for determining it is as follows:

[0102] make We can obtain:

[0103]

[0104] At this point, the overall friction coefficient is at a critical value, and this critical overall friction coefficient value is denoted as μ. c When μ > μ c When μ < μ, the calculation method adopts the strong form solution of equation (5); when μ < μ c When the calculation method adopts the weak form solution of equation (6), the calculation method is used.

[0105] like Figure 2 As shown, the critical value μ is given for different comprehensive friction coefficients. c The exponential change curve of the force on the side panel of the cargo box is obtained as the inflection point.

[0106] S4: Establish a multi-point support model and porosity model for material particles, and identify the relationship between particle stacking angle and the number of particle support points;

[0107] Let N represent the number of points in the multi-point support model of particles, n represent any positive integer, m represent the number of particles in each layer, and d represent the particle size (diameter). B i C i α i δ i h i (i = 2, 3, 4, ..., n) represent the center-to-center distance between the two ends of the transverse particles, the center-to-center distance between the two ends of the longitudinal particles, the stacking angle of the interlayer particles, the porosity of the material, and the interlayer height of the particles, respectively. Since it is impossible for all particles in a real material to have the same particle size, n is at least 2. Therefore, for a two-point support model (N = 2), as... Figure 3 As shown, we have:

[0108]

[0109] For the three-point support model (N=3), such as Figure 4 As shown, we have:

[0110]

[0111] For a four-point support model (N=4), such as Figure 5 As shown, we have:

[0112]

[0113] For an n-point support model (N = n, n ≥ 2), we have:

[0114]

[0115] S5: Based on measured data, the loading rate of a fully loaded flat-stacking cargo compartment is obtained. The actual cargo compartment loading rate is then combined with the porosity model to establish the relationship between the loading rate and the number of particle support points, thus determining a suitable multi-point particle support model. Specifically:

[0116] 1) The cargo compartments are filled in a flat stacking manner, and the loading volume M of the material is measured using a weighing system. l ;

[0117] 2) The cargo loading rate η can be written as:

[0118]

[0119] In the formula, ρ is the density of the ore material without considering porosity, and V is the volume of the material.

[0120] 3) Let η = δ n Calculate the suitable value for the number of points n in the multi-point contact model:

[0121]

[0122] In the formula, the operator CI() represents the most recent integer.

[0123] S6: Establish the relationship between finite element mesh size and material particle size;

[0124] like Figures 6-7 As shown, a strong correlation is established between the finite element mesh and the forces between the particles in the cargo compartment to facilitate the application of loads in subsequent simulation calculations. Therefore, the particle size of the multi-point support model of the material particles should be set according to the finite element mesh size as follows:

[0125] 1) Define the finite element mesh type and size. The side panels and floor of the cargo box adopt a uniform quadrilateral mesh configuration and mesh size s;

[0126] 2) Consistent particle size in multi-point support models. The centroid of the material particles must be aligned with the mesh nodes layer by layer, and the particle size d must satisfy:

[0127] s=d·sinα n (14)

[0128] 3) After the finite element mesh is strongly correlated with the multi-point contact model, the number of particles m in each layer in step S5 can be written as:

[0129]

[0130] In the formula, B represents the width of the cargo compartment opening.

[0131] S7: Establish the force distribution relationship between the side plates and bottom plate of the cargo compartment and the material particles based on the finite element mesh.

[0132] Assuming that the actual material particles should be supported by a two-point support model according to the method of steps S5 and S6, the multi-point support model of the material particles is calculated according to formula (11), and the material particles should be stacked at a 45° angle;

[0133] The following two sets of typical calculation examples are designed.

[0134] Example 1: Figure 6 As shown, T represents the unit normal contact force between particles, and s represents the size of the finite element mesh. When the width L of the cargo box floor is large, n1 and n2 are taken as 8 and 7 respectively, then:

[0135] T x (8) = (1,2,3,4,5,6,7,8) T

[0136] T y (7)=(9,11,13,14,13,11,9) T

[0137] Example 2: Figure 7 As shown, T represents the unit normal contact force between particles, and s represents the size of the finite element mesh. When the cargo box floor size W is relatively small, but the side panel height is large, n1 and n2 are taken as 10 and 4 respectively, then:

[0138] T x (10)=(1,2,3,4,5,6,6,7,6,7) T

[0139] T y (4) = (8,8,8,8) T

[0140] The calculation examples show that, with the changes in the dimensions of the cargo box side panels and floor, the cargo box floor may bear non-uniformly distributed loads, and the cargo box side panels may bear non-linear fluctuating loads.

Claims

1. A method for calculating the load of a mining dump truck, characterized in that: Includes the following steps: S1: Establish the interaction relationship between the two particles leaning against the corner of the cargo box and the side plate and bottom plate of the cargo box, obtain the force exerted by the side plate and bottom plate of the cargo box on the particles, and give the solutions for strong and weak friction. S2: Extend the interaction relationship established in step S1 to the entire cargo box material to obtain the force exerted on the material by the side plate and bottom plate of the cargo box. S3: Based on the numerical relationship between the strong and weak forms of friction established in step S1, give the critical value of the comprehensive friction coefficient. S4: Establish a multi-point support model and porosity model for material particles, and identify the relationship between particle stacking angle and the number of particle support points; S5: Combine the actual cargo loading rate with the porosity model to establish the relationship between the loading rate and the number of particle support points, and determine a suitable multi-point support model for particles; S6: Establish the relationship between finite element mesh size and material particle size; S7: Establish the force distribution relationship between the side plates and bottom plate of the cargo compartment and the material particles based on the finite element mesh; The specific method of S1 is as follows: Select two particles i and j located in the corner of the cargo box. Particle i is supported by the side panel of the cargo box and particle j, while particle j is supported by the bottom panel of the cargo box and particle i. The external force acting on particle i is its own weight M. i g. Comprehensive frictional force f i Normal force N on the side panel of the cargo box i The external force acting on particle j is its own weight M. j g. Comprehensive frictional force f j Normal force N on the cargo box floor j The angle between the intangents of particles i and j and the floor of the cargo box is θ. k Among them, the comprehensive frictional force f comprehensively considers the sliding friction between the material particles and the cargo box wall and the interlocking friction between the particles, and its expression is f=(μ 滑动 +μ 咬合 )N (1) μ=μ 滑动 +m 咬合 (2) In the formula, N is the normal force exerted by the cargo box wall on the particles, μ is the comprehensive friction coefficient, and μ 滑动 μ is the coefficient of sliding friction. 咬合 The coefficient of interlocking friction; When the combined frictional force dominates, the normal force N exerted by the side panel of the cargo box on the particles is... i The normal force N exerted by the cargo box floor on the particles j The expression for the frictional force, i.e., the formal solution, is: When the overall frictional force is secondary, the normal force N exerted by the side panel of the cargo box on the particles is... i The normal force N exerted by the cargo box floor on the particles j The expression for friction, i.e., the weak form solution, is:

2. The method for calculating the load of a mining dump truck according to claim 1, characterized in that: The specific steps of step S2 are as follows: Given the following two assumptions: 1) Traverse all paired particles in the box, their θ k It follows a normal distribution in the open interval (0°, 90°); 2) The particle size of the material inside the cargo compartment follows a normal distribution within a certain range; then... Use N s The normal force exerted by one side panel of the cargo compartment on the material, in N. b The normal force exerted by the cargo box floor on the material can be represented by the following frictional force: The weak form of the frictional force solution is: In equations (5) to (6), i, j, and k are indicator variables for the labeled particle mass and the included angle sequence, respectively, and n p Let G be the total number of material particles and G be the weight of the material.

3. The method for calculating the load of a mining dump truck according to claim 2, characterized in that: The calculation method for the critical value of the comprehensive friction coefficient is as follows: make We can obtain: At this point, the overall friction coefficient is at a critical value, and this critical overall friction coefficient value is denoted as μ. c When μ > μ c When the frictional force is strong, the calculation method adopts the solution of equation (5); when μ < μ c When, the calculation method adopts the weak form solution of friction force in equation (6).

4. A method for calculating the load of a mining dump truck according to any one of claims 1-2, characterized in that: Step S4 specifically involves: Let N represent the number of points in the multi-point support model, n represent any positive integer, m represent the number of particles in each layer, and d represent the particle size, i.e., diameter; B i C i α i δ i h i These represent the center-to-center distance between the two ends of the transverse particles, the center-to-center distance between the two ends of the longitudinal particles, the stacking angle of the interlayer particles, the porosity of the material, and the interlayer height of the particles, respectively, where i = 2, 3, 4, ..., n; since in actual materials, not all particles have the same size, n is at least 2; For an n-point support model, where n≥2, we have:

5. The method for calculating the load of a mining dump truck according to claim 4, characterized in that: Step S5 is as follows: S51: The cargo compartments are filled in a flat-stacking manner, and the loading volume M of the material is measured using a weighing system. l ; S52: The cargo loading rate η can be written as: In the formula, ρ is the density of the ore material without considering porosity, and V is the volume of the material; S53: Let η = δ n Calculate the suitable value for the number of points n in the multi-point contact model: In the formula, the operator CI() represents the most recent integer.

6. The method for calculating the load of a mining dump truck according to claim 4, characterized in that: The specific steps of step S6 are as follows: The particle size of the multi-point support model for material particles is set according to the finite element mesh size as follows: S61: Specify the finite element mesh type and size; the side panels and floor of the cargo box shall adopt a uniform quadrilateral mesh configuration and mesh size s. S62: For multi-point support models with consistent particle size, the centroid of the material particles must be aligned with the mesh nodes layer by layer, and the particle size d must meet the following requirements: s=d·sinα n (11) S63: After the finite element mesh is strongly correlated with the multi-point contact model, the number of particles m in each layer in step S5 is written as: In the formula, B represents the width of the cargo compartment opening, and the operator CI() represents the nearest integer.

7. The method for calculating the load of a mining dump truck according to claim 6, characterized in that: Step S7 is as follows: S71: Establish an n-point contact model for the material according to steps S5 and S6, with the material particles stacked at an angle α as specified in equation (8). n Stacking; S72: Create an n1-order vector T x (n1) The proportional relationship of the forces on each layer of the storage compartment side panel, n1 and the vector values ​​T of each layer. x (u) is: In the formula, h is the depth of the cargo compartment cavity. c b is the critical height for particle stacking. n This represents the number of particle layers at the critical height. In the formula, u is the spatial location sorting code from top to bottom; S73: Create an n² vector T y (n2) The proportional relationship of the forces on the floor of the storage compartment, n2 and the vector values ​​T of each layer. y (v) is: In the formula, v is the spatial position sorting code from left to right, L(v) is the left-order positioning state variable, and R(v) is the right-order positioning state variable;

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