Method for determining optimal value of ventilation area of mining wheel and method for evaluating overall strength of mining wheel

Abstract

The invention discloses a mining wheel ventilation area optimal value determination method and an overall strength evaluation method thereof. The mine car wheel lacks a processing method and a quantitative standard for correspondingly and accurately evaluating the overall structural strength of the wheel in different use stages; the method for determining the optimal value of the ventilation area of the mining wheel comprises the following steps of: establishing an initial mining wheel model according to standard bending moment data and standard radial load data; the method comprises the following steps of: performing stress field analysis and fatigue life evaluation on radial and bending working conditions of an initial mining wheel model by combining a finite element model and a method for evaluating the fatigue life of the wheel to obtain actual stress states and maximum load cycle index values of the wheel under different working conditions; and obtaining the optimal value of the wheel ventilation area through topological optimization according to the actual stress states of the wheel under different working conditions and the maximum number of cycles of the load.

Claims

1. A method for determining the optimal value of the ventilation area of ​​a mining wheel, characterized by: The method for determining the optimal value of the ventilation area of ​​a mining wheel is to establish an initial mining wheel model based on standard bending moment data and standard radial load data, and then perform stress field analysis and fatigue life evaluation on the radial and bending working conditions of the initial mining wheel model by combining the finite element model and the wheel fatigue life evaluation method to obtain the actual stress state of the wheel under different working conditions and the maximum load cycle number. The optimal value of the wheel ventilation area is obtained through topology optimization based on the actual stress state of the wheel under different working conditions and the maximum load cycle number.

2. The method for determining the optimal value of the ventilation area of ​​a mining wheel according to claim 1, characterized in that: By combining the finite element model with the wheel fatigue life evaluation method to perform stress field analysis and fatigue life evaluation on the radial and bending working conditions of the initial mining wheel model, the actual stress state of the wheel under different working conditions and the maximum load cycle number are obtained as follows: After establishing a finite element model of the wheel, bending or radial load boundary conditions were applied. The stress field distribution of the wheel was obtained through static analysis, and the finite element results were imported into nCode. The cyclic characteristics and amplitude of the load spectrum were determined by combining the SN curve of the wheel and the SN curve at weld 4. The fatigue analysis process was established using the GlyphWorks platform. The Miner linear criterion of the damage accumulation model and the Goodman stress correction method were selected to calculate the damage distribution of bending fatigue and radial fatigue, respectively. Finally, the weak areas were identified through the damage cloud map, and the fatigue life cycle number was output as the maximum load cycle number value.

3. The method for determining the optimal value of the ventilation area of ​​a mining wheel according to claim 2, characterized in that: The process of obtaining the optimal value of the wheel ventilation area through topology optimization based on the actual stress state of the wheel under different working conditions and the maximum number of load cycles is as follows: topology optimization analysis is performed on the initial mining wheel model under bending and radial working conditions, and according to the actual constraints, the variable density method is used to redistribute the material in the initial mining wheel model to obtain the topology optimization result after material redistribution, and the maximum value of the wheel ventilation area is obtained as the optimal value of the wheel ventilation area based on the topology optimization result.

4. The method for determining the optimal value of the ventilation area of ​​a mining wheel according to claim 3, characterized in that: The initial mining wheel model is subjected to topology optimization analysis under bending and radial working conditions. Based on the actual constraints, the variable density method is used to redistribute the material in the initial mining wheel model to obtain the topology optimization result after material redistribution. The process of obtaining the maximum value of the wheel ventilation area as the optimal value of the wheel ventilation area based on the topology optimization results is divided into the following steps: Step 1: Create the initial wheel geometry model in SoildWorks 3D modeling software according to the requirements of GB / T2883-2015 Specification Series for Engineering Machinery Rim and JB / T7155-2016 Technical Requirements for Earthmoving Machinery Wheels. Step 2: Search relevant books or standards to obtain wheel material properties; Step 3: Determine the simulation method based on the requirements of GB / T 5909-2009 "Performance Requirements and Test Methods for Commercial Vehicle Wheels"; Step 4: Calculate the radial load, bending load and preload of the bolt body 6; Step 5: In Ansys Workbench, use the Static Structural module to perform finite element simulation of the initial geometric model under bending and radial conditions. Simulation results are obtained, and the wheel's equivalent stress contour is extracted. The allowable stress of the material is compared with the maximum equivalent stress to assess whether the initial wheel model meets the strength requirements. Step 6: In Ansys Workbench, use the Topology Optimization module to perform topology optimization on the initial geometric model. Select the optimization area, determine the constraints, give the optimization goal, and use the variable density method to obtain the optimal material distribution. Step 7: Based on the results of topology optimization, the model is smoothed and, in combination with aerodynamic principles, the structure and number of ventilation holes are designed. After reverse modeling is completed, a predetermined number of solutions are given. Step 8: Evaluate the strength and life of the new model with ventilation holes in a predetermined number of schemes; Step 9: Perform fluid simulation on a predetermined number of schemes, and determine the wheel ventilation area value in the scheme with the largest ventilation volume and the largest heat dissipation intensity as the optimal wheel ventilation area value.

5. The method for determining the optimal value of the ventilation area of ​​a mining wheel according to claim 1, wherein: The specific process of the method for determining the optimal value of the ventilation area of ​​a mining wheel is as follows: establishing an initial wheel model, obtaining the wheel material properties from the initial wheel model, determining whether the strength and life of the initial wheel model meet the requirements, when the strength and life of the initial wheel model do not meet the requirements, re-establishing the initial wheel model based on relevant data, when the strength and life of the initial wheel model meet the requirements, applying bending moment data and radial load data to the initial wheel model as boundary conditions to analyze through topology optimization to obtain a ventilation hole model, and determining whether the strength and life of the ventilation hole model meet the relevant requirements, when the strength and life of the ventilation hole model do not meet the relevant requirements, applying bending moment data and radial load data to the initial wheel model as boundary conditions to analyze again through topology optimization to obtain a secondary ventilation hole model, when the strength and life of the ventilation hole model meet the relevant requirements, performing fluid simulation analysis on the ventilation hole model to determine the wheel ventilation area value in the solution with the maximum ventilation volume and the maximum heat dissipation intensity as the optimal value of the wheel ventilation area.

6. A method for determining an optimal value of ventilation area of ​​a mining wheel according to claim 1, 2, 3, 4 or 5, characterized in that: During the fatigue life evaluation of the initial mining wheel model, the calculation process of the stress gradient corrected cumulative damage under dynamic load is as follows: Based on the traditional Miner criterion, the stress gradient correction factor G is introduced. i and the frequency correction term F i , construct a modified cumulative damage model: In the above formula, G i Stress gradient correction factor, stress gradient correction factor G i The calculation formula is: In the above formula is the absolute value of the maximum stress gradient under the i-th level load, extracted through finite element simulation; σ r is the reference stress, and the material yield strength σ y 50% of the original value is used for dimensionless processing; α is the gradient sensitivity index, and its value range is 0.3≤α≤0.7, which is obtained through fatigue test calibration; Frequency correction term F i The calculation formula is: In the above formula, f i is the i-th level load frequency, reflecting the time-varying characteristics of the dynamic load; f0 is the reference frequency, which is the fundamental frequency of wheel rotation and is calculated using Formula 19: In the above formula, β is the frequency correction coefficient, and its value range is 0.05 ≤ β ≤ 0.15, which is determined by the variable amplitude loading test; the damage accumulation rate of the stress gradient correction factor Gi in the high stress gradient region is amplified; the frequency correction term Fi suppresses plastic deformation due to the cyclic hardening effect for high-frequency loads where f i > f0, reducing the damage rate F i , F i < 1; the situation for low-frequency loads where fi < f0 is vice versa.

7. The method for determining the optimal value of the ventilation area of ​​a mining wheel according to claim 6, characterized in that: During the fatigue life evaluation of the initial mining wheel model, a correction calculation process was also performed. The correction calculation process is as follows: the wheel 10 structure is adapted to the elastic-plastic behavior of the actual material, taking into account both lightweight and fatigue life, and introducing equivalent plastic strain ∈p to dynamically attenuate the stiffness: In the above formula, ∈p is the equivalent plastic strain of the unit, which is obtained by elastic-plastic finite element analysis; ρ e : Material density variable, the value range is usually 0≤ρ e ≤1; β is the plastic damage coefficient, ranging from 0.1≤β≤0.5, and is calibrated through uniaxial tensile test.

8. A method for evaluating the overall strength of a mining wheel, characterized by: The overall strength evaluation method for mining wheels is to obtain standard bending moment data and standard radial load data from actual mining wheels to establish a real-life mining wheel model, and then perform stress field analysis and fatigue life evaluation on the radial and bending working conditions of the real-life mining wheel model by combining the finite element model and the wheel fatigue life evaluation method to obtain the actual stress state of the wheel and the maximum load cycle number. According to the actual stress state of the wheel under different working conditions and the maximum load cycle number, the maximum wheel ventilation area is obtained through topology optimization, and the maximum wheel ventilation area is compared with the ventilation area of ​​the actual mining wheel. When the maximum wheel ventilation area is smaller than the ventilation area of ​​the actual mining wheel, it indicates that the mining wheel is in an over-strained state. When the maximum wheel ventilation area is 30% larger than the ventilation area of ​​the actual mining wheel, it indicates that the mining wheel is in normal performance and use.

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