A hammer pin articulated rotor probability life prediction method based on multiple failure modes

Abstract

The present application belongs to the technical field of finite element analysis, and proposes a hammer pin articulated rotor probability life prediction method based on multiple failure modes: firstly, the hammer pin articulated rotor in the forage rubbing crusher is respectively subjected to deterministic fatigue life prediction, deterministic wear life prediction and deterministic vibration fatigue life prediction; secondly, the hammer pin articulated rotor is subjected to uncertainty analysis based on the deterministic fatigue life prediction result, the deterministic wear life prediction result and the deterministic vibration fatigue life prediction result of the hammer pin articulated rotor; then, the hammer pin articulated rotor is subjected to probability fatigue life prediction, probability wear life prediction and probability vibration fatigue prediction based on the uncertainty analysis result of the hammer pin articulated rotor. The present application can accurately predict the life of the forage rubbing crusher and similar machines.

Description

Technical Field

[0001] This invention relates to the field of finite element analysis technology, and in particular to a method for predicting the probabilistic life of a hammer-pin hinged rotor based on multiple failure modes. Background Technology

[0002] To improve the utilization and conversion rate of straw resources, my country has independently developed a forage shredder that can shred agricultural fiber materials such as crop stalks, forage, and vines into filamentous segments, making them easier for livestock to eat and digest. During operation, the core component of the forage shredder, the hammer-pin hinged rotor, is highly susceptible to various failure modes, including fatigue, wear, and vibration fatigue, under the loads of high-speed rotation, centrifugal force, pressure from the high-speed airflow-material two-phase flow field, and its own gravity. The lifespan of the forage shredder largely depends on the failure modes and lifespan of the hammer-pin hinged rotor. Therefore, accurately predicting the lifespan of the hammer-pin hinged rotor under various failure modes is crucial for optimizing forage shredder maintenance strategies, reducing overall maintenance costs, preventing catastrophic failures, and mitigating safety risks.

[0003] Currently, deterministic methods are mainly used to predict the lifespan of forage shredders. However, due to dimensional errors in the parts during processing, the varying loads and material properties of components during operation, and the synergistic effects of material degradation and environmental load fluctuations over time, fatigue damage, hammer wear, and vibration fatigue damage in hammer-pin hinged rotors cannot be accurately described, leading to significant uncertainty in their lifespan. Therefore, deterministic methods cannot accurately describe the lifespan of hammer-pin hinged rotors under actual operating conditions, necessitating a method that comprehensively considers uncertainties and accurately predicts their lifespan. Summary of the Invention

[0004] The purpose of this invention is to provide a probabilistic life prediction method for hammer-pin hinged rotors based on multiple failure modes. This method combines deterministic life prediction methods with probabilistic statistical methods to perform uncertainty analysis and probabilistic life prediction for hammer-pin hinged rotors under multiple failure modes, thereby improving the accuracy of life prediction for forage shredders and similar machinery.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows:

[0006] This invention provides a method for predicting the probabilistic life of a hammer-pin hinged rotor based on multiple failure modes, comprising the following steps:

[0007] Deterministic fatigue life prediction, deterministic wear life prediction, and deterministic vibration fatigue life prediction were performed on the hammer-pin hinged rotor of the forage shredder.

[0008] Uncertainty analysis was performed on the hammer-pin hinged rotor based on the deterministic fatigue life prediction results, deterministic wear life prediction results, and deterministic vibration fatigue life prediction results.

[0009] Based on the uncertainty analysis results of the hammer-pin hinged rotor, probabilistic fatigue life prediction, probabilistic wear life prediction, and probabilistic vibration fatigue life prediction are performed on the hammer-pin hinged rotor.

[0010] As a further optimization, the deterministic fatigue life prediction of the hammer-pin hinged rotor in the forage shredder includes the following steps:

[0011] Numerical simulation was performed on the airflow-material coupled flow field inside the forage crusher, and the dynamic pressure generated by the airflow-material coupled flow field inside the forage crusher was applied to the hammer-pin hinged rotor.

[0012] The coupled flow field and the hammer-pin hinged rotor structure were calculated based on the two-way fluid-structure interaction method to obtain the stress load spectrum and the maximum equivalent stress.

[0013] The corrected average stress data is obtained based on the Gerber average stress correction method, and the deterministic fatigue life of the hammer-pin hinged rotor is calculated using Miner linear theory based on the corrected average stress data and the SN curve of the material.

[0014] As a further optimization, the deterministic wear life prediction of the hammer-pin hinged rotor in the forage shredder includes the following steps:

[0015] Based on the numerical simulation of the airflow-material coupling flow field inside the forage shredder, the wear amount of the hammer-pin hinged rotor is numerically calculated using the Archard wear model.

[0016] Predict the deterministic wear life of the hammer-pin hinged rotor based on the limit wear of the vulnerable parts specified in the forage shredder.

[0017] As a further optimization, the deterministic vibration fatigue life prediction of the hammer-pin hinged rotor in the forage shredder includes the following steps:

[0018] Modal and random vibration analyses of a hammer-pin hinged rotor were performed using the finite element method.

[0019] The deterministic vibration fatigue life of a hammer-pin hinged rotor is predicted by using the Bendaat narrowband approximation method combined with the Miner linear cumulative damage criterion.

[0020] As a further optimization, the uncertainty in uncertainty analysis includes physical uncertainty, model uncertainty, and data uncertainty;

[0021] Uncertainty analysis of hammer-pin hinged rotors based on deterministic fatigue life prediction results refers to:

[0022] Based on the deterministic fatigue life prediction results of the hammer-pin hinged rotor, it is found that the contact point between the hammer frame plate and the pin shaft on the hammer-pin hinged rotor is the location where the maximum stress occurs. At this time, the uncertainty of the structural parameters of the guillotine, hammer blade, hammer frame plate, pin shaft and sleeve, as well as the rotor speed working parameters, which affect the maximum stress and the location where the maximum stress occurs more than the preset value are analyzed.

[0023] At this point, the structural parameters of the guillotine, hammer blades, hammer frame plate, pin shaft, and sleeve are based on machining errors and belong to physical uncertainties. The rotor speed operating parameters are based on measurement errors and belong to physical uncertainties. When using computational fluid dynamics (CFD) and discrete element method (DEM) to numerically simulate the coupled flow field inside the forage crusher, the mathematical model used does not consider the discreteness of the structural dimensions and material characteristic parameters of the straw material, making the errors in the calculation process belong to model uncertainties.

[0024] As a further optimization, an uncertainty analysis is performed on the hammer-pin hinged rotor based on the deterministic wear life prediction results. This means:

[0025] Based on the deterministic wear life prediction results of the hammer-pin hinged rotor, it is found that the wear is most severe at the end of the cutter and hammer. At this time, the structural parameters and material properties of the cutter and hammer that affect the maximum wear of the cutter and hammer beyond the preset value, as well as the uncertainties of the material feed rate, feed speed and rotor speed working parameters, are analyzed.

[0026] At this point, the structural parameters of the guillotine and hammers are based on processing errors, which are physical uncertainties; the material property parameters degrade over time, which are also physical uncertainties; the material feed rate and feed speed are based on measurement errors, which are also physical uncertainties; when using computational fluid dynamics (CFD), discrete element method (DEM), and Archard wear model to numerically calculate the wear of the guillotine and hammers, the mathematical models used do not consider the discreteness of the structural dimensions and material property parameters of the straw material, making the errors in the calculation process part of model uncertainties.

[0027] As a further optimization, an uncertainty analysis is performed on the hammer-pin hinged rotor based on the deterministic vibration fatigue life prediction results. This means:

[0028] Based on the deterministic vibration fatigue life prediction results of the hammer-pin hinged rotor, it is found that: under random vibration, the contact point between the pin and the hammer frame plate is the location most prone to vibration fatigue. At this time, the physical uncertainties of the rotor centroid offset, hammer structural parameters, guillotine structural parameters and rotor speed working parameters that are affected by vibration fatigue and the location most prone to occur exceeding the preset value are analyzed.

[0029] At this point, the uncertainty of random vibration load and rotor centroid offset caused by wear of hammers and cutters belongs to data uncertainty.

[0030] As a further optimization, based on the fatigue uncertainty analysis results of the hammer-pin hinged rotor, probabilistic fatigue life prediction of the hammer-pin hinged rotor is performed, including the following steps:

[0031] The hammer blade length, hammer blade width, hammer frame plate thickness, guillotine height, guillotine thickness, guillotine width, guillotine length, pin diameter, sleeve diameter, and rotor speed are set as design variables.

[0032] 150 sets of data were generated using Latin hypercube sampling;

[0033] The maximum equivalent stress of the hammer-pin hinged rotor is obtained by CFD-DEM coupled calculation and finite element analysis, taking into account the uncertainties of the hammer-pin hinged rotor structure and the value data of the working parameters.

[0034] Based on the mean and variance of the maximum equivalent stress obtained from finite element analysis, 10,000 sets of data were sampled using the Monte Carlo method to calculate the probabilistic fatigue life of the hammer-pin hinged rotor. The calculated life results were then fitted to a distribution to obtain the probabilistic fatigue life prediction results of the hammer-pin hinged rotor.

[0035] As a further optimization, based on the wear uncertainty analysis results of the hammer-pin hinged rotor, probabilistic wear life prediction of the hammer-pin hinged rotor is performed, including the following steps:

[0036] Hammer length, hammer width, hammer thickness, guillotine thickness, guillotine width, guillotine length, guillotine and hammer material hardness, rotor speed, material feed rate, and feed speed are selected as design variables;

[0037] Considering the uncertainties in the structural parameters of the hammer-pin hinged rotor, the hardness of the cutter and hammer materials, and the distribution of the crusher's working parameters, 100 sets of data were generated through Latin hypercube sampling. By coupling calculations on these 100 sets of data, the maximum wear of the hammer-pin hinged rotor's hammers and cutter was obtained. Based on the calculated maximum wear of the 100 sets, its distribution map was fitted.

[0038] Based on the mean and variance of the maximum wear amount obtained from discrete element analysis, 10,000 sets of data were sampled using the Monte Carlo method to calculate the probabilistic wear life of the hammer-pin hinged rotor. The calculated life results were then fitted to a distribution to obtain the probabilistic wear life prediction results of the hammer-pin hinged rotor.

[0039] As a further optimization, based on the vibration fatigue uncertainty analysis results of the hammer-pin hinged rotor, probabilistic vibration fatigue life prediction of the hammer-pin hinged rotor is performed, including the following steps:

[0040] The 24 hammer blades are divided into 6 groups, with 4 hammer blades in each group. The 4 guillotines are arranged in a circumferential distribution.

[0041] The rotor centroid offset refers to the relative wear between each set of hammers and cutters, that is, the difference in wear between two opposite hammers or cutters in each set of hammers or cutters.

[0042] The relative wear of each set of hammers and cutters, hammer length, hammer width, hammer thickness, cutter thickness, cutter width, cutter length, and rotor speed are selected as design variables.

[0043] By using Latin hypercube sampling, 100 sets of data were randomly generated according to their distribution rules. The values ​​of the centroid offset, structural parameters and working parameters of the hammer-pin hinged rotor, which are uncertain, were considered in the vibration fatigue life prediction.

[0044] Random vibration analysis was performed using the finite element method, and its distribution diagram was fitted.

[0045] The stress response power spectral density at the critical point is derived. The Monte Carlo method is used to sample 10,000 sets of data to calculate the probabilistic vibration fatigue life of the hammer-pin hinged rotor. The calculated life results are then fitted to the distribution to obtain the probabilistic vibration fatigue life prediction results of the hammer-pin hinged rotor.

[0046] The beneficial effects of this invention are: considering the influence of uncertain factors such as structure and working parameters, materials, actual load and service environment, this invention combines deterministic life prediction method with probabilistic statistical method to complete the prediction of probabilistic fatigue life, probabilistic wear life and probabilistic vibration fatigue life of hammer pin hinge rotor, which can provide methodological guidance for the accurate prediction of the life of forage crusher and similar machinery and the formulation of subsequent maintenance strategies. Attached Figure Description

[0047] Figure 1 This is a flowchart of a probabilistic life prediction method for a hammer-pin hinged rotor based on multiple failure modes in Embodiment 1 of the present invention;

[0048] Figure 2 This is a schematic diagram of the forage shredder and the hammer-pin hinged rotor structure in Embodiment 2 of the present invention;

[0049] Figure 3 This is a schematic diagram of the stress distribution cloud of the hammer-pin hinged rotor in Embodiment 2 of the present invention;

[0050] Figure 4 This is a schematic diagram of the maximum stress load spectrum of the hammer-pin hinged rotor in Embodiment 2 of the present invention;

[0051] Figure 5 This is a schematic diagram of the wear cloud when the hammer blade works for 1 second in Embodiment 2 of the present invention;

[0052] In this diagram, 1 represents the frame, 2 represents the toothed plate, 3 represents the housing, 4 represents the feed chute, 5 represents the discharge pipe, 6 represents the fixed blade, 7 represents the hammer-pin hinged rotor, 7-1 represents the guillotine, 7-2 represents the hammer frame plate, 7-3 represents the hammer blade, 7-4 represents the throwing blade, 7-5 represents the sleeve, and 7-6 represents the pin. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0054] Example 1

[0055] This embodiment provides a probabilistic life prediction method for hammer-pin hinged rotors based on multiple failure modes. See the flowchart below. Figure 1 The method may include the following steps:

[0056] S1. Deterministic fatigue life prediction, deterministic wear life prediction, and deterministic vibration fatigue life prediction are performed on the hammer-pin hinged rotor in the forage shredder, respectively.

[0057] S2. Uncertainty analysis is performed on the hammer-pin hinged rotor based on the deterministic fatigue life prediction results, deterministic wear life prediction results, and deterministic vibration fatigue life prediction results.

[0058] S3. Based on the uncertainty analysis results of the hammer-pin hinged rotor, the probabilistic fatigue life prediction, probabilistic wear life prediction, and probabilistic vibration fatigue life prediction of the hammer-pin hinged rotor are respectively performed.

[0059] In this embodiment, the fatigue cumulative damage theory, the Archard wear model, and the Bendahl narrowband approximation method can be used to perform deterministic fatigue life prediction, deterministic wear life prediction, and deterministic vibration fatigue life prediction for the hammer-pin hinged rotor, a core component of the forage shredder. Based on this, considering the influence of uncertainties such as structural and operating parameters, materials, actual loads, and service environment, the deterministic life prediction method is combined with probabilistic statistical methods. Based on Latin hypercube sampling and Monte Carlo sampling methods, probabilistic fatigue life prediction, probabilistic wear life prediction, and probabilistic vibration fatigue life prediction are performed for the hammer-pin hinged rotor. Therefore, it has important guiding significance for the accurate prediction of the life of forage shredders and similar machinery and the formulation of subsequent maintenance strategies.

[0060] Example 2

[0061] Based on Example 1, see Figure 2 The forage shredder used in this embodiment is mainly composed of a frame 1, a toothed plate 2, a housing 3, a feed trough 4, a discharge pipe 5, a fixed blade 6, and a hammer-pin hinged rotor 7. The hammer-pin hinged rotor 7 is composed of a guillotine blade 7-1, a hammer frame plate 7-2, hammer blades 7-3, a throwing blade 7-4, a sleeve 7-5, and a pin shaft 7-6.

[0062] This embodiment uses the 9R-50A forage shredder as an example. Its operating conditions are: the rotor speed of the hammer-pin hinged type forage shredder is 2400 r / min; the shredded material is yellow corn stalks with a density of 1.301 × 10⁻⁶. -7 kg / mm 3 The feed rate is 0.5 kg / s. The outer diameter of the hammer-pin hinged rotor 7 is... 410mm, hammer frame plate 7-2 diameter is 250mm diameter, 4mm thickness; hammer blade 7-3 has dimensions of 170mm x 35mm x 5mm (length x width x thickness); throwing blade 7-4 has a thickness of 4mm; main shaft length is 1000mm; outer diameter of the outer casing is... 490mm, shell wall thickness is 4mm; the length and height of the feed inlet are 230mm and 285mm respectively; the cross-section of the discharge pipe 5 is a square section of 170mm×170mm, the height of the discharge straight pipe is 330mm, and the inner and outer radii of the discharge bend are 830mm and 1000mm respectively.

[0063] In practical applications, this embodiment can be implemented through the following steps:

[0064] S1. Deterministic life prediction of the hammer-pin hinged rotor, a core component of the forage shredder.

[0065] S11. To accurately predict the deterministic fatigue life of the hammer-pin hinged rotor 7, a two-way fluid-structure interaction method is used to calculate the coupled flow field and the structure of the hammer-pin hinged rotor 7 to obtain the stress concentration region and the maximum equivalent stress. See [link to relevant documentation]. Figure 3 In this embodiment, the maximum equivalent stress on the rotor is mainly concentrated at the contact point between the pin 7-6 and the hammer frame plate 7-2, with a maximum equivalent stress of 214.45 MPa. (See [link to relevant documentation]). Figure 4 The stress value at the point of maximum stress varies approximately periodically with time. The maximum stress value is 214.45 MPa, the minimum stress value is 185.27 MPa, and the average stress value is 199.86 MPa. Based on the corrected average stress data and the material's SN curve, the fatigue life of the hammer-pin hinged rotor 7 can be calculated using Miner's linear theory, resulting in a fatigue life of 5.90 × 10⁻⁶ MPa for the forage shredder's hammer-pin hinged rotor 7. 7 This equates to 497.3 hours.

[0066] S12. To study the wear characteristics of the rotor during actual operation, the CFD-DEM method was used to calculate the complex multiphase flow field inside the forage shredder. Based on this, the Archard wear model was used to calculate the wear characteristics of the hammer-pin hinged rotor 7 during actual operation. (See also...) Figure 5 The wear of the hammer-pin hinged rotor 7 was calculated 1 second after it entered a stable working state. It can be seen that the axial and radial wear of the hammers 7-3 is uneven. Radially, the outer ends of the hammers 7-3 furthest from the shaft show more severe wear. Axially, the wear of the hammers 7-3 at both ends of the crushing chamber is significantly greater than that of the middle hammers 7-3, and the maximum wear of the hammers 7-3 is 5.05 × 10⁻⁶. -6 mm. In this embodiment, the cumulative wear of the guillotine 7-1 changes linearly with time, and the linear equation of the maximum wear versus time can be derived as follows:

[0067] ,

[0068] In the formula, x This represents the maximum wear amount; y For time.

[0069] The deterministic wear life of the hammer-pin hinged rotor 7 can be calculated using the above formula as 73.24 hours.

[0070] S13. Considering the deterministic vibration fatigue life of the hammer-pin hinged rotor 7 caused by vibration load, modal analysis and random vibration analysis of the hammer-pin hinged rotor 7 are performed using the finite element method. Based on this, the deterministic vibration fatigue life of the hammer-pin hinged rotor 7 is predicted. Using the Bendaat narrowband approximation method and combined with the Miner linear cumulative damage criterion, the deterministic vibration fatigue life of the hammer-pin hinged rotor 7 is calculated to be 1.17 × 10⁻⁶. 8 s, equivalent to 3.25 × 10 4 h. Comparative analysis of the rotor deterministic fatigue life prediction, rotor wear life prediction, and rotor vibration fatigue life prediction results shows that the rotor deterministic life, from largest to smallest, is the vibration fatigue life of 3.25 × 10⁻⁶. 4 The values ​​of h, fatigue life (497.30h), and wear life (73.24h) indicate that the hammer-pin hinged rotor 7 is most prone to wear failure, followed by fatigue failure, and least prone to vibration fatigue failure.

[0071] S2. Uncertainty analysis of the hammer-pin hinged rotor, a core component of the forage shredder;

[0072] S21. Based on the deterministic fatigue life prediction results of the hammer-pin hinged rotor 7, it can be seen that the contact point between the hammer frame plate 7-2 and the pin shaft 7-6 on the hammer-pin hinged rotor 7 is the dangerous part, i.e., the location where the maximum stress occurs. Therefore, the analysis mainly considers the uncertainty of the structural parameters of the guillotine 7-1, hammer blade 7-3, hammer frame plate 7-2, pin shaft 7-6, sleeve 7-5, etc., which have a significant impact on the maximum stress and the location where the maximum stress occurs, as well as the working parameters such as the rotor speed. That is, the analysis is conducted on the physical uncertainties of the length and width of the hammer blade 7-3, the thickness of the hammer frame plate 7-2, the height, thickness, width, and length of the guillotine 7-1, the diameter of the pin shaft 7-6, the diameter of the sleeve 7-5, and the rotor speed. When using computational fluid dynamics (CFD) and discrete element method (DEM) to numerically simulate the coupled flow field inside a forage crusher, the mathematical model used did not consider the discreteness of the structural dimensions and material property parameters of the straw material, resulting in errors in the calculation process that are part of the model uncertainty.

[0073] S22. According to the deterministic wear life prediction results of the hammer-pin hinged rotor 7, the wear is most severe at the ends of the guillotine 7-1 and hammer 7-3, and they will be the first to reach the wear limit and fail, thus being the dangerous parts. Therefore, the analysis mainly considers the uncertainties of the structural parameters and material properties of the guillotine 7-1 and hammer 7-3, which have a significant impact on the maximum wear of the guillotine 7-1 and hammer 7-3, as well as the working parameters such as material feed rate and feed speed. That is, the analysis is conducted on the physical uncertainties of the length and width of the hammer 7-3, the height, thickness, width, and length of the guillotine 7-1, the material hardness of the guillotine 7-1 and hammer 7-3, the rotor speed, the material feed rate, and the feed speed. When numerically calculating the wear of the guillotine 7-1 and hammer 7-3 using computational fluid dynamics (CFD), discrete element method (DEM), and the Archard wear model, the mathematical models used did not consider the discreteness of the structural dimensions and material characteristic parameters of the straw material, resulting in errors in the calculation process belonging to model uncertainty.

[0074] S23. Based on the deterministic vibration fatigue life prediction results of the hammer-pin hinged rotor 7, it is known that under random vibration, the contact point between the pin 7-6 and the hammer frame plate 7-2 is the most vulnerable area for vibration fatigue. Furthermore, during operation, the wear conditions of each hammer 7-3 and the guillotine 7-1 differ significantly, leading to a shift in the center of mass of the hammer-pin hinged rotor 7, further exacerbating fatigue fracture caused by random vibration loads. Therefore, the analysis primarily considers the physical uncertainties of operating parameters that significantly affect vibration fatigue and the most vulnerable location, such as the rotor center of mass shift (replaced by the relative wear of each set of hammers 7-3 and guillotine 7-1), the length, width, and thickness of hammers 7-3, the thickness, width, and length of guillotine 7-1, and the rotor speed. The uncertainty of random vibration load and rotor centroid offset caused by wear of hammer blades 7-3 and cutter blades 7-1 belongs to data uncertainty.

[0075] S3, Hammer-pin hinged rotor, a core component of the forage shredder, is predicted to have a probabilistic lifespan.

[0076] S31. Taking into account the impact of uncertainty on life prediction, probabilistic life prediction of the hammer-pin hinged rotor 7 can be carried out.

[0077] In probabilistic fatigue life prediction, the length and width of hammer blade 7-3, the thickness of hammer frame plate 7-2, the height, thickness, width, and length of guillotine 7-1, the diameter of pin shaft 7-6, the diameter of sleeve 7-5, and the rotor speed are taken as design variables. 150 sets of data are generated using Latin hypercube sampling. The CFD-DEM coupled calculation and finite element analysis are performed on the structural and operational parameter values ​​of the hammer-pin hinged rotor 7, considering uncertainties, to obtain the maximum equivalent stress of the hammer-pin hinged rotor 7. The mean of the maximum equivalent stress of the hammer-pin hinged rotor 7 is 205.603 MPa, the variance is 7.526 MPa, and the maximum equivalent stress ranges from 180 MPa to 220 MPa, mainly concentrated between 205 MPa and 210 MPa. Based on the mean and variance of the maximum equivalent stress obtained from the finite element analysis, 10,000 sets of data were sampled using the Monte Carlo method to calculate the probabilistic fatigue life of the hammer-pin hinged rotor 7. The calculated life results were then fitted with a distribution. The predicted probabilistic fatigue life of the hammer-pin hinged rotor 7 follows a log-normal distribution ln N 1~ N (17.8697, 0.628) 2 The average fatigue life was 585.80 hours. The probabilistic fatigue prediction life was mainly distributed between 334 hours and 668 hours.

[0078] S32. In the probabilistic wear life prediction, the following parameters are selected as design variables: hammer blade 7-3 length, hammer blade 7-3 width, hammer blade 7-3 thickness, guillotine 7-1 thickness, guillotine 7-1 width, guillotine 7-1 length, guillotine 7-1 and hammer blade 7-3 material hardness, rotor speed, material feed rate, and feed speed. Considering the uncertainties in the distribution of hammer-pin hinged rotor structural parameters, guillotine and hammer blade material hardness, and crusher operating parameters, 100 sets of data are generated through Latin hypercube sampling. By coupling calculations on these 100 sets of data, the maximum wear of hammer blade 7-3 and guillotine 7-1 in the hammer-pin hinged rotor 7 can be obtained. Based on the calculated 100 sets of maximum wear, their distribution map is fitted. The average maximum wear of the hammer-pin hinged rotor 7 is 1.11 × 10⁻⁶. -5 The wear rate is 1.06569 × 10⁻⁶ mm, with a variance of 1.06569 × 10⁻⁶ mm, and the maximum wear range is 8.0 × 10⁻⁶ mm. -6 mm ~1.6×10 -5 mm, mainly concentrated in 1.0×10 -5 mm ~ 1.1 × 10 -5 Between mm. Based on the mean and variance of the maximum wear amount obtained from the discrete element analysis above, 10,000 sets of data were sampled using the Monte Carlo method to calculate the probabilistic wear life of the hammer-pin hinged rotor 7, and the calculated life results were fitted to a distribution. The predicted probabilistic wear life of the rotor follows a log-normal distribution lnN 1~ N (4.3228, 0.0983) 2 The average wear life is 75.78 hours. The probabilistic wear prediction life is mainly distributed between 70 and 80 hours.

[0079] S33. In probabilistic vibration fatigue life prediction, to understand the specific conditions of each hammer 7-3, the 24 hammers 7-3 are divided into 6 groups, with 4 hammers 7-3 in each group, arranged circumferentially. The relative wear of the hammers 7-3 and the cutter 7-1, the length, width, and thickness of the hammers 7-3, the thickness, width, and length of the cutter 7-1, and the rotor speed are selected as design variables for each group (6 groups in total). Using Latin hypercube sampling, 100 sets of data are randomly generated according to their distribution pattern. The values ​​of the centroid offset, structural parameters, and operating parameters of the hammer-pin hinged rotor 7, which account for uncertainties in the vibration fatigue life prediction, are also considered. The above data were subjected to random vibration analysis using the finite element method, and its distribution was fitted. The mean maximum equivalent stress of the hammer-pin hinged rotor 7 under vibration load was 9.3 MPa, with a variance of 1.085 MPa. The maximum equivalent stress ranged from 7 MPa to 11.5 MPa, mainly concentrated between 9.5 MPa and 10 MPa. Based on the above analysis, the stress response power spectral density at the critical point was derived. Using the Monte Carlo method, 10,000 sets of data were sampled to calculate the probabilistic vibration fatigue life of the hammer-pin hinged rotor 7. The calculated life results were then fitted with a distribution. The predicted probabilistic vibration fatigue life of the hammer-pin hinged rotor 7 followed a log-normal distribution ln N 1~ N (19.3833, 0.7485) 2 The average lifespan is 3.38 × 10⁻⁶. 8 s (i.e. 9.39 × 10) 4 h). The predicted probabilistic vibration fatigue life is mainly distributed in the range of 2.77 × 10⁻⁶. 4 h~4.16×10 4 Between h.

[0080] In summary, the mean probabilistic life of the hammer-pin hinged rotor, from largest to smallest, is the vibration fatigue life of 9.39 × 10⁻⁶. 4 The fatigue life of 585.80h and the wear life of 75.78h show that the hammer-pin hinged rotor 7 is most prone to wear failure, followed by fatigue failure, and least prone to vibration fatigue failure.

[0081] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for predicting the probabilistic life of a hammer-pin hinged rotor based on multiple failure modes, characterized in that, Includes the following steps: Deterministic fatigue life prediction, deterministic wear life prediction, and deterministic vibration fatigue life prediction were performed on the hammer-pin hinged rotor of the forage shredder. Uncertainty analysis was performed on the hammer-pin hinged rotor based on the deterministic fatigue life prediction results, deterministic wear life prediction results, and deterministic vibration fatigue life prediction results. Based on the uncertainty analysis results of the hammer-pin hinged rotor, probabilistic fatigue life prediction, probabilistic wear life prediction, and probabilistic vibration fatigue life prediction are carried out for the hammer-pin hinged rotor. When performing deterministic wear life prediction for the hammer-pin hinged rotor in a forage shredder, the following steps are included: Based on the numerical simulation of the airflow-material coupling flow field inside the forage shredder, the wear amount of the hammer-pin hinged rotor is numerically calculated using the Archard wear model. Predict the deterministic wear life of the hammer-pin hinged rotor based on the limit wear of the vulnerable parts specified in the forage shredder. When performing deterministic vibration fatigue life prediction for the hammer-pin hinged rotor in a forage shredder, the following steps are included: Modal and random vibration analyses of a hammer-pin hinged rotor were performed using the finite element method. The deterministic vibration fatigue life of the hammer-pin hinged rotor is predicted by using the Bendaat narrowband approximation method combined with the Miner linear cumulative damage criterion. Uncertainty analysis of hammer-pin hinged rotors based on deterministic vibration fatigue life prediction results refers to: Based on the deterministic vibration fatigue life prediction results of the hammer-pin hinged rotor, it is found that: under random vibration, the contact point between the pin and the hammer frame plate is the location most prone to vibration fatigue. At this time, the physical uncertainties of the rotor centroid offset, hammer structural parameters, guillotine structural parameters and rotor speed working parameters that are affected by vibration fatigue and the location most prone to occur exceeding the preset value are analyzed. At this point, the uncertainty of random vibration load and rotor centroid offset caused by wear of hammers and cutters belongs to data uncertainty; Based on the uncertainty analysis results of vibration fatigue of the hammer-pin hinged rotor, the probabilistic vibration fatigue life prediction of the hammer-pin hinged rotor is carried out, including the following steps: The 24 hammer blades are divided into 6 groups, with 4 hammer blades in each group. The 4 guillotines are arranged in a circumferential distribution. The rotor centroid offset refers to the relative wear between each set of hammers and cutters, that is, the difference in wear between two opposite hammers or cutters in each set of hammers or cutters. The relative wear of each set of hammers and cutters, hammer length, hammer width, hammer thickness, cutter thickness, cutter width, cutter length, and rotor speed are selected as design variables. By using Latin hypercube sampling, 100 sets of data were randomly generated according to their distribution rules. The values ​​of the centroid offset, structural parameters and working parameters of the hammer-pin hinged rotor, which are uncertain, were considered in the vibration fatigue life prediction. Random vibration analysis was performed using the finite element method, and its distribution diagram was fitted. The stress response power spectral density at the critical point is derived. The Monte Carlo method is used to sample 10,000 sets of data to calculate the probabilistic vibration fatigue life of the hammer-pin hinged rotor. The calculated life results are then fitted to the distribution to obtain the probabilistic vibration fatigue life prediction results of the hammer-pin hinged rotor.

2. The method for predicting the probabilistic life of a hammer-pin hinged rotor based on multiple failure modes according to claim 1, characterized in that, The deterministic fatigue life prediction of the hammer-pin hinged rotor in the forage shredder includes the following steps: Numerical simulation was performed on the airflow-material coupled flow field inside the forage crusher, and the dynamic pressure generated by the airflow-material coupled flow field inside the forage crusher was applied to the hammer-pin hinged rotor. The coupled flow field and the hammer-pin hinged rotor structure were calculated based on the two-way fluid-structure interaction method to obtain the stress load spectrum and the maximum equivalent stress. The corrected average stress data is obtained based on the Gerber average stress correction method, and the deterministic fatigue life of the hammer-pin hinged rotor is calculated using Miner linear theory based on the corrected average stress data and the SN curve of the material.

3. The method for predicting the probabilistic life of a hammer-pin hinged rotor based on multiple failure modes according to claim 1, characterized in that, Uncertainty in uncertainty analysis includes physical uncertainty, model uncertainty, and data uncertainty; Uncertainty analysis of hammer-pin hinged rotors based on deterministic fatigue life prediction results refers to: Based on the deterministic fatigue life prediction results of the hammer-pin hinged rotor, it is found that the contact point between the hammer frame plate and the pin shaft on the hammer-pin hinged rotor is the location where the maximum stress occurs. At this time, the uncertainty of the structural parameters of the guillotine, hammer blade, hammer frame plate, pin shaft and sleeve, as well as the rotor speed working parameters, which affect the maximum stress and the location where the maximum stress occurs more than the preset value are analyzed. At this point, the structural parameters of the guillotine, hammer blades, hammer frame plate, pin shaft, and sleeve are based on machining errors and are therefore subject to physical uncertainty. The rotor speed operating parameters are based on measurement errors and are also subject to physical uncertainty. When using computational fluid dynamics (CFD) and discrete element method (DEM) to numerically simulate the coupled flow field inside the forage crusher, the mathematical model used does not consider the discreteness of the structural dimensions and material characteristic parameters of the straw material, making the errors in the calculation process subject to model uncertainty.

4. The method for predicting the probabilistic life of a hammer-pin hinged rotor based on multiple failure modes according to claim 3, characterized in that, Uncertainty analysis of hammer-pin hinged rotors based on deterministic wear life prediction results refers to: Based on the deterministic wear life prediction results of the hammer-pin hinged rotor, it is found that the wear is most severe at the end of the cutter and hammer. At this time, the structural parameters and material properties of the cutter and hammer that affect the maximum wear of the cutter and hammer beyond the preset value, as well as the uncertainties of the material feed rate, feed speed and rotor speed working parameters, are analyzed. At this point, the structural parameters of the guillotine and hammers are based on processing errors, which are physical uncertainties; the material property parameters degrade over time, which are also physical uncertainties; the material feed rate and feed speed are based on measurement errors, which are also physical uncertainties; when using computational fluid dynamics (CFD), discrete element method (DEM), and Archard wear model to numerically calculate the wear of the guillotine and hammers, the mathematical models used do not consider the discreteness of the structural dimensions and material property parameters of the straw material, making the errors in the calculation process part of model uncertainties.

5. The method for predicting the probabilistic life of a hammer-pin hinged rotor based on multiple failure modes according to claim 1, characterized in that, Based on the fatigue uncertainty analysis results of the hammer-pin hinged rotor, the probabilistic fatigue life prediction of the hammer-pin hinged rotor is performed, including the following steps: The hammer blade length, hammer blade width, hammer frame plate thickness, guillotine height, guillotine thickness, guillotine width, guillotine length, pin diameter, sleeve diameter, and rotor speed are set as design variables. 150 sets of data were generated using Latin hypercube sampling; The maximum equivalent stress of the hammer-pin hinged rotor is obtained by CFD-DEM coupled calculation and finite element analysis, taking into account the uncertainties of the hammer-pin hinged rotor structure and the value data of the working parameters. Based on the mean and variance of the maximum equivalent stress obtained from finite element analysis, 10,000 sets of data were sampled using the Monte Carlo method to calculate the probabilistic fatigue life of the hammer-pin hinged rotor. The calculated life results were then fitted to a distribution to obtain the probabilistic fatigue life prediction results of the hammer-pin hinged rotor.

6. The method for predicting the probabilistic life of a hammer-pin hinged rotor based on multiple failure modes according to claim 1, characterized in that, Based on the wear uncertainty analysis results of the hammer-pin hinged rotor, the probabilistic wear life prediction of the hammer-pin hinged rotor is performed, including the following steps: Hammer length, hammer width, hammer thickness, guillotine thickness, guillotine width, guillotine length, guillotine and hammer material hardness, rotor speed, material feed rate, and feed speed are selected as design variables; Considering the uncertainties in the structural parameters of the hammer-pin hinged rotor, the hardness of the cutter and hammer materials, and the distribution of the crusher's working parameters, 100 sets of data were generated through Latin hypercube sampling. By coupling calculations on these 100 sets of data, the maximum wear of the hammer-pin hinged rotor's hammers and cutter was obtained. Based on the calculated maximum wear of the 100 sets, its distribution map was fitted. Based on the mean and variance of the maximum wear amount obtained from discrete element analysis, 10,000 sets of data were sampled using the Monte Carlo method to calculate the probabilistic wear life of the hammer-pin hinged rotor. The calculated life results were then fitted to a distribution to obtain the probabilistic wear life prediction results of the hammer-pin hinged rotor.

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