Pneumatic conveying pipeline wear life analysis method based on fatigue damage

Abstract

The invention provides a pneumatic conveying pipeline wear life analysis method based on fatigue damage, which comprises the following steps: establishing a pneumatic conveying model based on a gas-solid two-phase flow theory, and solving a gas-solid acting force of a to-be-analyzed pipeline to obtain a solid phase solving result; according to the solid phase solving result, the wear depth of the to-be-analyzed pipeline is obtained through calculation of a wear model; according to a solid phase solving result, calculating accumulated contact energy between the material particles and the to-be-analyzed pipeline through a relative wear model; according to the accumulated contact energy, calculating and obtaining a fatigue damage variable of the to-be-analyzed pipeline based on a linear fatigue accumulated damage theory; and performing wear life analysis on the to-be-analyzed pipeline according to the wear depth and the fatigue damage variable to obtain an analysis result. According to the method, the fatigue damage pneumatic conveying pipeline wear life prediction analysis is considered, and the pipeline life prediction accuracy is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline wear analysis, and particularly to a method for analyzing the wear life of a pneumatic conveying pipeline based on fatigue damage. Background Art

[0002] Pneumatic conveying is a system for transporting solid material particles through positive pressure blowing or negative pressure suction of air flow in a pipeline. Solid materials commonly transported in this way include flour, pulverized coal, ore powder, granular chemicals, grains, medical waste, domestic waste, and other solid materials. Pneumatic conveying has many advantages, such as flexible conveying paths and spaces, closed and safe operating conditions, and low maintenance costs. However, there are also some disadvantages. For example, in a dilute-phase conveying system, the collision rate between solid materials and the pipe wall is relatively high, and the wear of the conveying system is serious, which is the main factor restricting the operating efficiency of the pneumatic conveying system.

[0003] Pipeline wear depends on the movement characteristics of materials in the pipeline. Pneumatic conveying belongs to the research category of gas-solid two-phase flow. However, due to the current research's insufficient understanding of multiphase flow phenomena and processes and the unclear understanding of the coupling mechanism between phases, the research on the movement characteristics of gas-solid two-phase flow mainly simplifies theoretical derivations, physical test observations, and data analysis. Considering the limitations of test conditions and testing equipment, Computational Fluid Dynamics (CFD) simulation has also become the main research method for studying multiphase flow. Considering the large number of collision behaviors existing in the process of pneumatic conveying of materials in a pipeline, the Discrete Element Method (DEM) can directly simulate the collision processes between different particle types, sizes, shapes, and particles. Therefore, the CFD-DEM method is mainly used to study the movement state and wear characteristics during the pneumatic conveying process.

[0004] In the actual operation of pneumatic conveying pipelines, the pipeline materials are mainly steel. Other metal materials, ceramics, polymer plastics, composite materials, etc. are less used due to cost reasons. The wear of steel pipelines during the entire service life cycle consists of tangential cutting plastic damage and normal fatigue brittle damage. However, the existing research on the life of pneumatic conveying pipelines mostly only considers cutting wear and ignores fatigue damage, resulting in insufficient accuracy in the study of pipeline life. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the related art. For this purpose, the present invention provides a method for analyzing the wear life of a pneumatic conveying pipeline based on fatigue damage.

[0006] The present invention provides a method for analyzing the wear life of a pneumatic conveying pipeline based on fatigue damage, including:

[0007] S1: Establish a pneumatic conveying model based on the gas-solid two-phase flow theory, solve the gas-solid interaction force on the pipeline to be analyzed through the pneumatic conveying model, and obtain the solid-phase solution result;

[0008] S2: Calculate the wear depth of the pipeline to be analyzed through the wear model according to the solid-phase solution result;

[0009] S3: Calculate the cumulative contact energy between the material particles and the pipeline to be analyzed through the relative wear model according to the solid-phase solution result;

[0010] S4: Calculate the fatigue damage variable of the pipeline to be analyzed based on the linear fatigue cumulative damage theory according to the cumulative contact energy;

[0011] S5: Conduct a wear life analysis on the pipeline to be analyzed according to the wear depth and the fatigue damage variable, and obtain the analysis result.

[0012] According to a method for analyzing the wear life of a pneumatic conveying pipeline based on fatigue damage provided by the present invention, step S1 further includes:

[0013] S11: Establish a fluid control equation;

[0014] S12: Establish a material particle control equation;

[0015] S13: Realize gas-solid two-phase coupling according to the fluid control equation and the material particle control equation to obtain a pneumatic conveying model;

[0016] S14: Solve the gas-solid interaction force on the pipeline to be analyzed through the pneumatic conveying model, and obtain the solid-phase solution result.

[0017] According to a method for analyzing the wear life of a pneumatic conveying pipeline based on fatigue damage provided by the present invention, step S13 further includes:

[0018] S131: In the current time step, calculate the gas flow field through the fluid control equation;

[0019] S132: Calculate the particle information according to the gas flow field through the material particle control equation and transmit it back to the fluid control equation. The particle information includes particle velocity and particle position;

[0020] S133: Calculate the action information within the current time step according to the gas flow field and the particle information, and transmit the action information to the fluid control equation and the material particle control equation as the initial conditions for solving in the next time step.

[0021] A method for analyzing the wear life of a pneumatic conveying pipeline based on fatigue damage provided by the present invention, wherein the fluid control equation in step S11 is solved by a CFD solution model, and the CFD solution model includes: RNG k-ε turbulence model, k-ε turbulence model, Realizable k-ε turbulence model, large eddy simulation model, and hybrid RANS / LES model.

[0022] A method for analyzing the wear life of a pneumatic conveying pipeline based on fatigue damage provided by the present invention, wherein the wear model in step S2 includes Archard wear model and Oka impact wear model.

[0023] A method for analyzing the wear life of a pneumatic conveying pipeline based on fatigue damage provided by the present invention, wherein the expression of the wear depth in step S2 is:

[0024]

[0025] Q = WF n d t ;

[0026]

[0027] wherein, h w is the calculated wear depth, Q is the material area removed by wear, A is the geometric area where the pipeline to be analyzed contacts with the particles, W is the wear coefficient, F n is the normal contact force of the contact surface where the pipeline to be analyzed contacts with the particles, d t is the tangential movement distance, K is a dimensionless constant, and H v is the Vickers hardness of the worn material.

[0028] A method for analyzing the wear life of a pneumatic conveying pipeline based on fatigue damage provided by the present invention, wherein the cumulative contact energy in step S3 includes normal cumulative contact energy and tangential cumulative contact energy;

[0029] The expression of the normal cumulative contact energy is:

[0030] E n = ∑|F n v n δ t |;

[0031] wherein, E n is the normal cumulative contact energy, F n is the normal contact force of the contact surface where the pipeline to be analyzed contacts with the particles, v n is the normal relative velocity calculated at each time step of the DEM model, and δ t is the time step;

[0032] The expression of the normal cumulative contact energy is:

[0033] E t =∑|F t v t δ t |;

[0034] Among them, E t is the tangential cumulative contact energy, F t is the tangential contact force between the pipe and the particle to be analyzed, v t Tangential relative velocity calculated for each time step of the DEM model.

[0035] According to a fatigue damage-based wear life analysis method for pneumatic conveying pipelines provided by the present invention, the expression of the fatigue damage variable in step S4 is:

[0036]

[0037] Where D is the calculated fatigue damage variable, σ is the current stress level, A is the geometric area where the pipeline to be analyzed contacts the particles, B is the inherent fatigue strength parameter of the pipeline material to be analyzed, l is the deformation of the pipeline to be analyzed along the thickness direction, and E is the Young's modulus.

[0038] According to a fatigue damage-based wear life analysis method for pneumatic conveying pipelines provided by the present invention, step S5 further comprises:

[0039] S51: establishing a first index control criterion according to the wear depth;

[0040] S52: Establishing a second index control criterion based on fatigue damage variables;

[0041] S53: Taking the first index control criterion and the second index control criterion as a dual index control criterion, when any one of the dual index control criterion is at a critical value, it is determined that the pipeline to be analyzed has reached its life limit.

[0042] According to a fatigue damage-based wear life analysis method for pneumatic conveying pipelines provided by the present invention, the expression of the first index control criterion in step S51 is:

[0043] h w ≥30%T k ;

[0044] Among them, h w To calculate the wear depth, T k is the wall thickness of the pipeline to be analyzed;

[0045] The expression of the second index control criterion in step S52 is:

[0046] D = 1;

[0047] Where D is the calculated fatigue damage variable.

[0048] Beneficial Effects

[0049] The present invention provides a wear life analysis method for pneumatic conveying pipelines based on fatigue damage, which combines the gas-solid two-phase flow theory and the wear model, and can more accurately simulate the interaction between material particles and pipelines during pneumatic conveying, thereby more accurately calculating the wear depth and fatigue damage variables of the pipeline, and improving the accuracy of the analysis; in addition, traditional methods often only focus on the wear depth, and the present invention also introduces the linear fatigue cumulative damage theory, taking into account the influence of the cumulative contact energy between material particles and pipelines on pipeline fatigue damage, making the analysis results more comprehensive and reliable.

[0050] By accurately analyzing the wear life of the pipeline, the present invention can timely discover potential wear problems and take corresponding maintenance measures, thereby effectively extending the service life of the pipeline and reducing production interruptions and maintenance costs caused by pipeline wear; it can also provide a scientific basis for the design of the pneumatic conveying system, reduce pipeline wear and fatigue damage by optimizing pipeline materials, structures or operating parameters, and improve the overall performance and efficiency of the system; accurate wear life analysis helps to timely discover and deal with safety hazards, prevent safety accidents such as leakage and explosion caused by pipeline wear, and improve the safety of the pneumatic conveying system.

[0051] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0053] Figure 1 It is a schematic flow chart of a method for analyzing wear life of a pneumatic conveying pipeline based on fatigue damage provided by an embodiment of the present invention;

[0054] Figure 2 It is a flow chart of a method for performing wear life analysis on a pipeline to be analyzed based on wear depth and fatigue damage variables provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0056] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0057] Combine the following Figures 1 to 2 Embodiments of the present invention are described.

[0058] like Figure 1 As shown, the present invention provides a method for analyzing the wear life of a pneumatic conveying pipeline based on fatigue damage, comprising:

[0059] S1: A pneumatic conveying model is established based on the gas-solid two-phase flow theory, and the gas-solid interaction force of the pipeline to be analyzed is solved through the pneumatic conveying model to obtain the solid phase solution result.

[0060] Furthermore, in step S1, a pneumatic conveying CFD-DEM model is first established in combination with the gas-solid two-phase flow theory to solve the gas phase flow field, solid phase motion state, position and force conditions, as well as gas-solid interaction force and momentum exchange.

[0061] Wherein, step S1 further comprises:

[0062] S11: Establish fluid control equations.

[0063] Specifically, in CFD, the gas is regarded as a continuous phase, following the Navier-Stokes (NS) equation and solving it according to the conservation of mass and momentum. The expression of its continuity equation is:

[0064]

[0065] The expression of the momentum conservation equation is:

[0066]

[0067] Among them, ε g is the volume fraction, ρ g is the gas density, t is the time, u g is the gas velocity, x is the coordinate position, i is the first particle index value, j is the second particle index value, p is the gas pressure, μ g is the gas viscosity, S is the momentum exchange between the gas phase and the solid phase, and g is the gravitational acceleration.

[0068] Among them, the fluid control equation in step S11 is solved by a CFD solution model, and the CFD solution model includes: RNG k-ε turbulence model, k-ε turbulence model, Realizable k-ε turbulence model, large eddy simulation model, and hybrid RANS / LES model.

[0069] Furthermore, for the pneumatic conveying CFD-DEM model established in step S11, the flow field of the gas phase can be solved by the RNG k-ε turbulence model of the computational fluid dynamics (CFD) method, the motion state, position and force of the solid phase are solved by the Hertz-Mindlin non-sliding contact model of the discrete element method (DEM), and the gas-solid interaction force and momentum exchange are calculated by the drag model, thereby realizing the gas-solid two-phase coupling. In addition, the CFD solution model can be replaced by conventional CFD solution models such as the k-ε turbulence model, the Realizable k-ε turbulence model, the large eddy simulation (LES), and the hybrid RANS / LES model.

[0070] Furthermore, since the gas phase flow in the pneumatic conveying pipeline is turbulent, the physical parameters in the flow field, such as velocity, pressure, temperature, etc., vary randomly and nonlinearly with time and space, so the present invention uses the RNG k-ε turbulence model to solve the flow field.

[0071] The most important feature of the RNG k-ε turbulence model is the coefficient of the ε equation The time-averaged strain rate of the main phase flow is introduced, so that It is not only related to the flow, but also a function of the spatial coordinates. The RNG k-ε turbulence model takes into account the rotation and swirl conditions in the flow, and can better handle the flow with high strain rate and large streamline curvature at the pipe elbow.

[0072] S12: Establish material particle control equation.

[0073] Furthermore, the motion of material particles can be decomposed into two forms: translation and rotation. The mechanical behavior is described by the contact force between particles, between particles and walls, and between particles and surrounding fluids, and the particle motion is determined by combining the gas phase momentum conservation equation. According to Newton's second law, the control equation of particles in DEM at any time is as follows:

[0074]

[0075]

[0076] In the above formula, m i is the mass of particle i, v i is the velocity of particle i, f p～g,i is the gas-solid interaction force, f c,ij is the rebound force when particle i contacts particle j or the wall, g is the gravitational acceleration, k i is the total number of particles, f d,ij is the viscous damping force when particle i contacts particle j or the wall, I i is the moment of inertia of particle i, ω i is the angular velocity of particle i, T ij For torque.

[0077] Contact force is the interaction force between particles and particles, or between particles and walls. It can be decomposed into normal and tangential components. Since it involves many physical processes, it is currently difficult to find an accurate and widely applicable model to describe the collision process. The most widely used contact force model is the Hertz-Mindlin non-sliding contact model. The calculation method for the normal and tangential components of the contact force is as follows:

[0078]

[0079]

[0080] In the above formula, f ct,ij and f cn,ij are the tangential and normal components of the contact force, δ t and δ n is the tangential overlap and normal overlap, μ is the friction coefficient, k t and k n is the tangential stiffness and normal stiffness, and the specific calculation method is shown in the following formula:

[0081]

[0082]

[0083] In the above formula, G* is the equivalent shear modulus, E * is the equivalent Young's modulus, R * is the equivalent radius.

[0084] S13: A gas-solid two-phase coupling is realized according to the fluid control equation and the material particle control equation to obtain a pneumatic conveying model.

[0085] For the CFD-DEM method, the gas phase and the solid phase realize gas-solid two-phase coupling through momentum exchange, in which the gas drag is calculated by the Di Felice drag model, and the expression is as follows:

[0086]

[0087]

[0088]

[0089] In the formula, f drag,i is the gas drag force on the particle, C d is the drag coefficient, A is the projected area of ​​the particle in the direction of fluid motion, is the relative velocity between particles and fluid, and Re is the Reynolds number.

[0090] Wherein, step S13 further comprises:

[0091] S131: In the current time step, the gas flow field is calculated by using the fluid control equation.

[0092] S132: According to the gas flow field, particle information is calculated by the material particle control equation and transmitted back to the fluid control equation, wherein the particle information includes particle velocity and particle position.

[0093] S133: Calculate the action information in the current time step according to the gas flow field and the particle information, and transmit the action information to the fluid control equation and the material particle control equation as the initial condition for solving the next time step.

[0094] Furthermore, the CFD-DEM coupling is as follows: within each calculation time step, CFD first calculates the gas flow field according to the initial conditions; then the velocity and position of the particles after a single time step are solved in DEM, and the particle information is transmitted back to CFD; then the porosity, gas-solid interaction force and momentum exchange of the grid within the time step are calculated based on the gas flow field, particle velocity and position information; finally, all the above data are transmitted back to CFD and DEM respectively as the initial conditions for solving the gas flow field and particles in the next time step.

[0095] S14: Solving the gas-solid interaction force of the pipeline to be analyzed by using the pneumatic conveying model to obtain a solid phase solution result.

[0096] S2: According to the solid phase solution result, the wear depth of the pipeline to be analyzed is obtained by wear model calculation.

[0097] The wear model in step S2 includes the Archard wear model and the Oka impact wear model. The Oka impact wear model is used to calculate the wear depth of a high-flow rate pneumatic conveying pipeline that is prone to impact wear.

[0098] Wherein, the expression of the wear depth in step S2 is:

[0099]

[0100] Q=WF n d t ;

[0101]

[0102] Among them, h w To calculate the wear depth, Q is the area of ​​material removed by wear, A is the geometric area of ​​contact between the analyzed pipe and the particles, W is the wear coefficient, and F is n is the normal contact force between the pipe and the particle to be analyzed, d t is the tangential moving distance, K is a dimensionless constant, H v is the Vickers hardness of the wear material.

[0103] Furthermore, the Archard wear model, also known as the absolute wear model, is currently widely used to calculate the surface wear depth of the wear area. This model assumes that the surface wear volume of the material is proportional to the work done by the material on the material surface friction and inversely proportional to the surface hardness. The normal force between the material particles and the geometric contact surface is linearly related to the wear amount. The Archard wear model is an empirical model that can quantitatively predict the wear depth of the material.

[0104] S3: According to the solid phase solution result, the cumulative contact energy between the material particles and the pipeline to be analyzed is obtained by calculating the relative wear model.

[0105] Wherein, the accumulated contact energy in step S3 includes normal accumulated contact energy and tangential accumulated contact energy;

[0106] The expression of the normal cumulative contact energy is:

[0107] E n =∑|F n v n δ t|;

[0108] Among them, E n is the normal cumulative contact energy, F n is the normal contact force between the pipe and the particle to be analyzed, v n is the normal relative velocity calculated for each time step of the DEM model, δ t is the time step;

[0109] The expression of the normal cumulative contact energy is:

[0110] E t =∑|F t v t δ t |;

[0111] Among them, E t is the tangential cumulative contact energy, F t is the tangential contact force between the pipe and the particle to be analyzed, v t Tangential relative velocity calculated for each time step of the DEM model.

[0112] The relative wear model is a wear model for calculating the normal and tangential impact wear areas. The relative wear indicators calculated by the model are the normal cumulative contact energy and the tangential cumulative contact energy, which are used to quantify the cumulative contact energy generated by material collision and sliding.

[0113] S4: According to the accumulated contact energy, fatigue damage variables of the pipeline to be analyzed are calculated based on linear fatigue cumulative damage theory.

[0114] Furthermore, the Basquin power function expression of the material fatigue life SN curve is:

[0115]

[0116] Among them, N f is the fatigue life corresponding to the current stress level, B is the inherent fatigue strength parameter of the material, and c is the material performance constant.

[0117] The material strain energy under the condition of load action number n is:

[0118]

[0119] Among them, W q (n) is the material strain energy, n is the number of load actions, N fis the fatigue life corresponding to the current stress level, A is the geometric area where the pipeline to be analyzed contacts the particles, l is the deformation of the pipeline to be analyzed along the thickness direction, E is the Young's modulus, and then, combined with the Palmgren-Miner theory of linear fatigue cumulative damage, the damage variable is defined from the perspective of energy dissipation. The specific expression is as follows.

[0120] Wherein, the expression of the fatigue damage variable in step S4 is:

[0121]

[0122] Where D is the calculated fatigue damage variable and σ is the current stress level.

[0123] S5: Perform wear life analysis on the pipeline to be analyzed according to the wear depth and the fatigue damage variable to obtain analysis results.

[0124] Wherein, step S5 further comprises:

[0125] S51: establishing a first index control criterion according to the wear depth;

[0126] S52: Establishing a second index control criterion based on fatigue damage variables;

[0127] S53: Taking the first index control criterion and the second index control criterion as a dual index control criterion, when any one of the dual index control criterion is at a critical value, it is determined that the pipeline to be analyzed has reached its life limit.

[0128] The expression of the first index control criterion in step S51 is:

[0129] h w ≥30%T k ;

[0130] Among them, h w To calculate the wear depth, T k is the wall thickness of the pipeline to be analyzed. The specific proportion of the wall thickness of the wear depth can be adjusted and set according to the actual operating conditions.

[0131] The expression of the second index control criterion in step S52 is:

[0132] D = 1;

[0133] Where D is the calculated fatigue damage variable.

[0134] Furthermore, a dual-index control criterion for pipeline wear life based on wear depth and fatigue damage variables is established, and the index that reaches the life limit first is used as the control index to realize pipeline wear life analysis considering fatigue damage.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fatigue damage-based wear life analysis method for pneumatic conveying pipelines, characterized in that: include: S1: A pneumatic conveying model is established based on the gas-solid two-phase flow theory, and the gas-solid interaction force of the pipeline to be analyzed is solved by the pneumatic conveying model to obtain a solid phase solution result; S2: according to the solid phase solution result, the wear depth of the pipeline to be analyzed is obtained by wear model calculation; S3: according to the solid phase solution result, the cumulative contact energy between the material particles and the pipeline to be analyzed is obtained by calculating the relative wear model; S4: According to the accumulated contact energy, based on the linear fatigue cumulative damage theory, calculate and obtain the fatigue damage variable of the pipeline to be analyzed; S5: Perform wear life analysis on the pipeline to be analyzed according to the wear depth and the fatigue damage variable to obtain analysis results.

2. The wear life analysis method of pneumatic conveying pipeline based on fatigue damage according to claim 1 is characterized in that: Step S1 further comprises: S11: Establish fluid control equations; S12: Establish material particle control equation; S13: realizing gas-solid two-phase coupling according to the fluid control equation and the material particle control equation to obtain a pneumatic conveying model; S14: Solving the gas-solid interaction force of the pipeline to be analyzed by using the pneumatic conveying model to obtain a solid phase solution result.

3. The wear life analysis method of pneumatic conveying pipeline based on fatigue damage according to claim 2 is characterized in that: Step S13 further comprises: S131: In the current time step, the gas flow field is calculated by using the fluid control equation; S132: According to the gas flow field, particle information is calculated by the material particle control equation and transmitted back to the fluid control equation, wherein the particle information includes particle velocity and particle position; S133: Calculate the action information in the current time step according to the gas flow field and the particle information, and transmit the action information to the fluid control equation and the material particle control equation as the initial condition for solving the next time step.

4. The wear life analysis method of pneumatic conveying pipeline based on fatigue damage according to claim 2 is characterized in that: The fluid control equation in step S11 is solved by a CFD solution model, and the CFD solution model includes: RNG k-ε turbulence model, k-ε turbulence model, Realizable k-ε turbulence model, large eddy simulation model, and hybrid RANS / LES model.

5. The wear life analysis method of pneumatic conveying pipeline based on fatigue damage according to claim 1 is characterized in that: The wear model in step S2 includes the Archard wear model and the Oka impact wear model.

6. The wear life analysis method of pneumatic conveying pipeline based on fatigue damage according to claim 1 is characterized in that: The expression of the wear depth in step S2 is: Q=WF n d t ; Among them, h w To calculate the wear depth, Q is the area of ​​material removed by wear, A is the geometric area of ​​contact between the analyzed pipe and the particles, W is the wear coefficient, and F is n is the normal contact force between the pipe and the particle to be analyzed, d t is the tangential moving distance, K is a dimensionless constant, H v is the Vickers hardness of the wear material.

7. The wear life analysis method of pneumatic conveying pipeline based on fatigue damage according to claim 1 is characterized in that: The accumulated contact energy in step S3 includes normal accumulated contact energy and tangential accumulated contact energy; The expression of the normal cumulative contact energy is: E n =∑|F n v n δ t |; Among them, E n is the normal cumulative contact energy, F n is the normal contact force between the pipe and the particle to be analyzed, v n is the normal relative velocity calculated for each time step of the DEM model, δ t is the time step; The expression of the normal cumulative contact energy is: E t =∑|F t v t δ t |; Among them, E t is the tangential cumulative contact energy, F t is the tangential contact force between the pipe and the particle to be analyzed, v t Tangential relative velocity calculated for each time step of the DEM model.

8. The wear life analysis method of pneumatic conveying pipeline based on fatigue damage according to claim 7 is characterized in that: The expression of the fatigue damage variable in step S4 is: Where D is the calculated fatigue damage variable, σ is the current stress level, A is the geometric area where the pipeline to be analyzed contacts the particles, B is the inherent fatigue strength parameter of the pipeline material to be analyzed, l is the deformation of the pipeline to be analyzed along the thickness direction, and E is the Young's modulus.

9. The wear life analysis method of pneumatic conveying pipeline based on fatigue damage according to claim 1 is characterized in that: Step S5 further comprises: S51: establishing a first index control criterion according to the wear depth; S52: Establishing a second index control criterion based on fatigue damage variables; S53: Taking the first index control criterion and the second index control criterion as a dual index control criterion, when any one of the dual index control criterion is at a critical value, it is determined that the pipeline to be analyzed has reached its life limit.

10. The wear life analysis method of pneumatic conveying pipeline based on fatigue damage according to claim 9, characterized in that: The expression of the first index control criterion in step S51 is: h w ≥330%T k ; Among them, h w To calculate the wear depth, T k is the wall thickness of the pipeline to be analyzed; The expression of the second index control criterion in step S52 is: D＝1； Where D is the calculated fatigue damage variable.

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