A method for analyzing the online cycle of the sector guide roller of a continuous casting machine based on finite element analysis

Abstract

The present invention relates to a method for analyzing the online cycle of a continuous casting machine sector guide roller based on finite element analysis, which comprises the following steps: establishing a finite element mathematical model for a group of down rollers of the continuous casting machine sector guide roller, collecting relevant data of the down rollers of the continuous casting machine sector, simulating the dynamic behavior of the material during high temperature deformation by using bilinear materials, and generating material constitutive curves; using augmented Lagrangian to perform theoretical analysis on the nonlinear contact between the roller surface and the slab surface, and by artificially introducing the penetration amount and the initial contact stiffness coefficient, performing iterative calculations, completing the estimation of the external fatigue cycle of the down roller, generating a life cloud map and a damage cloud map, and finding the lowest life point for estimation. Sub-model calculations are used to further verify the results. The method is simple and reliable, and the estimation of the external fatigue cycle of the down roller is completed within the finite element software, which is fast and efficient. The present invention can be widely used in the estimation and analysis of the online cycle of the sector guide roller of the continuous casting machine.

Description

Technical Field

[0001] The invention relates to a finite element mathematical modeling simulation method, in particular to a method for analyzing the online cycle of a sector guide roller of a continuous casting machine based on the finite element. Background Art

[0002] The online cycle of mechanical parts is often related to the friction and wear between parts. In the prior art, the production of mechanical parts usually starts with designing the product according to actual needs, and then testing the product with load. If the product does not meet the design requirements during the experiment, the product is redesigned and then tested again until the product is qualified. This process is not only time-consuming, but also has a high rework rate, resulting in high production costs and low efficiency. Using finite element mathematical modeling simulation methods to accurately simulate the friction and wear of mechanical parts in the production process can analyze the online cycle of mechanical parts, improve the design of parts, and save R&D costs.

[0003] One method used in industrial applications is to obtain relevant data through experiments. However, the experimental cost is high, and only information about certain points can be obtained during the experiment, and the distribution of data in the entire area cannot be obtained. With the advancement of finite element technology, especially the rapid development of large-scale finite element software, the online cycle of mechanical parts can use these software to obtain very satisfactory numerical solutions. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a method for analyzing the online cycle of the guide rollers of the continuous casting machine sector segments based on finite element analysis, which can more completely simulate the wear process of the guide rollers of the continuous casting machine sector segments and accurately obtain the online cycle of the guide rollers of the continuous casting machine sector segments.

[0005] To achieve the above object, the present invention adopts the following technical scheme: a method for analyzing the online cycle of the sector guide roller of a continuous casting machine based on finite element analysis, which comprises the following steps:

[0006] 1) Problem description and setting of relevant parameter boundary conditions

[0007] a. Establish a finite element mathematical model for a group of pressing rollers of the sector guide rollers of the continuous casting machine;

[0008] b. Collect relevant data of the continuous casting machine sector pressure roller, such as motor speed, slab speed, slab temperature, slab size, drive roller diameter, material, etc.;

[0009] c. Use bilinear materials to simulate the dynamic behavior of metals during high temperature deformation and generate material constitutive curves;

[0010] 2) The augmented Lagrangian method is used to theoretically analyze the nonlinear contact of the plastic deformation between the roller surface and the slab surface, and the iterative calculation is completed by artificially introducing the penetration amount and the initial contact stiffness coefficient;

[0011] 3) Mesh quality analysis

[0012] a. To ensure the convergence of nonlinear calculation and the accuracy of contact detection, the hexahedral Solid186 high-order unit is used as the finite element mathematical model;

[0013] b. Determine the target unit and contact unit of the contact model, and analyze the three-dimensional structure and coupled field contact;

[0014] c. Adjust the initial contact state, close the gaps and penetrations between the contact surfaces, and prevent the contact from affecting the calculation results of the contact stress due to initial penetration;

[0015] 4) Calculation process and results

[0016] a. First check the entire calculation convergence process to ensure the correct result. The calculation convergence curve can be used to determine whether the calculation process has converged and completed the calculation, and the Von-Mises stress is calculated;

[0017] b. Using sub-model calculations can better refine the stress distribution and further verify the results;

[0018] c. To ensure accurate calculation, the penetration amount needs to be controlled within a certain range, and the penetration value and friction force need to be calculated;

[0019] d. Final summary of all calculated data, such as displacement, strain, stress, penetration, friction stress, sub-model stress, full model stress, etc.;

[0020] 5) Estimation of external fatigue cycle of the press roller: Based on the calculation of fatigue analysis software, fatigue analysis is performed on the roller surface that produces the maximum Von-mises stress, and life cloud diagram and damage cloud diagram are generated to find the lowest point of life for estimation.

[0021] The step 1) uses 800°C bilinear material to simulate the material constitutive curve.

[0022] The related analysis of plastic deformation in step 2) uses a static mechanical analysis module, and the augmented Lagrangian method is used to calculate the nonlinear contact between the roller surface and the slab surface.

[0023] In the step 3), the model uses hexahedral Solid186 high-order units to ensure the convergence of nonlinear calculations and the accuracy of contact detection, and the contact model uses Target170 target units and Conta174 contact units.

[0024] In step 5), based on the calculation of fatigue analysis software, fatigue analysis is performed on the roller surface that produces the maximum Von-mises stress to find the lowest point of life for estimation.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1) The present invention can more accurately predict the friction and wear phenomenon of the sector guide rollers. 2) The present invention can improve the calculation efficiency and calculation accuracy of the simulation. 3) The present invention predicts the service life of the product, saves research and development costs, reduces the rework rate, and effectively improves production efficiency. 4) Since finite element software is used for calculation, the setting is simple and easy to use, which avoids complicated calculations and has higher precision and accuracy. 5) The present invention has a wide range of use and can be widely used in various types of wear simulations involving contact, especially suitable for guiding the wear analysis of the sector guide rollers of continuous casting machines. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart of simulating and analyzing the online cycle of the sector guide roller of the present invention.

[0028] Figure 2 It is the material constitutive curve diagram of Q235 steel at different temperatures of the present invention.

[0029] Figure 3 It is the material constitutive curve of the present invention at 800°C.

[0030] Figure 4 It is a schematic diagram of the principle of the augmented Lagrangian algorithm of the present invention.

[0031] Figure 5 It is a finite element model diagram of the fan-shaped segment of the continuous casting machine of the present invention.

[0032] Figure 6 It is the grid quality cloud map of the present invention.

[0033] Figure 7 It is the mesh quality analysis diagram of the present invention.

[0034] Figure 8 This is a grid warpage analysis diagram of the present invention.

[0035] Fig. 9 It is the Jacobian diagram of the mesh quality of the present invention.

[0036] Fig.10 This is the principle diagram of the Target170 target unit of the present invention

[0037] Fig.11 This is the principle diagram of the Conta174 unit of the present invention

[0038] Fig.12 This is the initial contact state analysis diagram of the present invention

[0039] Fig.13 This is the initial contact state diagram of the present invention

[0040] Fig.14 It is a graph of the calculation convergence curve of the present invention.

[0041] Fig.15 It is the Von-Mises stress cloud diagram of the present invention.

[0042] Fig.16 It is the displacement cloud diagram of the present invention.

[0043] Fig.17 It is the strain cloud diagram of the present invention.

[0044] Fig.18 It is the sub-model finite element model of the present invention.

[0045] Fig.19 It is the stress calculation cloud diagram of the sub-model of the present invention.

[0046] Fig. 20 It is the penetration value cloud diagram of the present invention.

[0047] Fig.21 It is the friction cloud diagram of the present invention.

[0048] Fig. 22 It is a cloud diagram of the life of the pressing roller of the present invention.

[0049] Fig.23 This is the damage cloud diagram of the pressing roller of the present invention. DETAILED DESCRIPTION

[0050] The simulation method of the present invention is further described below in conjunction with the embodiments and drawings:

[0051] The present invention provides a method for analyzing the online cycle of a continuous casting machine sector guide roller based on finite element analysis, and the embodiment includes the following steps:

[0052] 1. Problem description and setting of relevant parameter boundary conditions

[0053] a. Basic parameters

[0054] The relevant data of the provided materials and the pressing roller are summarized in Table 1-1.

[0055] Table 1-1 Slab and press roll parameters

[0056]

[0057] b. Slab issues and material parameters

[0058] During the high temperature deformation process of metals, the dynamic behavior of the material will have a significant impact, see Figure 2As shown, in order to simplify the material constitutive curve, a bilinear material is used to simulate the material constitutive curve.

[0059] c. This calculation uses the constitutive curve of the material at 800℃ to replace the effect of temperature on the material, excluding the effect of thermal stress and thermal expansion on the material. The constitutive curve of the material at 800℃ is shown in Figure 3 , material parameters are shown in Table 1-2.

[0060] density 7850kg / m3 Young's modulus 7.80E+10 Poisson's ratio 0.3 Yield limit 1.40E+08 Tangent modulus 1.45E+09

[0061] 2. Select computational models and related theories

[0062] According to the actual working conditions, the calculation process will include plastic deformation, large deformation analysis and contact-related analysis. Considering the slow speed of the whole process, the static mechanical analysis module can be used. The augmented Lagrangian method is used for the nonlinear contact between the roller surface and the slab surface. Compared with other contact algorithms, the augmented Lagrangian method is stable. The iterative calculation is completed by artificially introducing the penetration amount and the initial contact stiffness coefficient.

[0063] The principle formula of the augmented Lagrangian algorithm is: F norma1 =K normal ·X penetration +λ, due to the existence of the λ factor, the calculation convergence is enhanced. See the schematic diagram for the principle. Figure 4 .

[0064] 3. Mesh quality analysis and related parameters

[0065] a. Basic grid parameters

[0066] The model uses hexahedral Solid186 high-order elements to ensure the convergence of nonlinear calculations and the accuracy of contact detection. The finite element model is shown in Figure 5 . Detailed mesh quality and quantity are shown in Table 3-1.

[0067] project quantity Total number of nodes 455483 Total number of units 123252 Total number of volume elements 94320 Total number of contact elements 28932

[0068] b. Mesh quality analysis

[0069] For difficult calculations such as nonlinear convergence difficulty, the grid must meet certain quality requirements. See the quality cloud diagram for details. Figure 6 shown.

[0070] The mesh quality parameters were calculated respectively, and the mesh quality coefficient was > 0.74, see Figure 7 The overall quality is good. Warp < 0.10, the grid is regular, see Figure 8 . Mesh quality Jacobi 1.3<,>1, see Fig. 9 .

[0071] Comprehensive analysis shows that the quality of the grid cells is good and can be used for calculation.

[0072] c. Contact unit and initial state analysis

[0073] When studying the contact between two objects, the surface of one object is usually used as the contact surface and the surface of the other object is used as the target surface. The concept of contact-target pair has been widely used in finite element simulation. For rigid-flexible contact, the contact surface is associated with the deformable body, and the target surface must be a rigid-flexible contact surface. For flexible-flexible contact, both the contact surface and the target surface are associated with the deformable body. The contact surface and the target surface constitute a "contact pair".

[0074] The contact model uses the Target170 target element and the Conta174 contact element. Conta174 is used to represent the contact and sliding between the three-dimensional target surface and the deformable surface defined by this element. This element is suitable for three-dimensional structure and coupled field contact analysis. It can be used for both pair contact and general contact, see Fig.10 .

[0075] Target170 is used to represent the various three-dimensional "target" surfaces of the associated contact elements (Conta173, Conta174, Conta175, Conta176, and Conta177). The contact elements themselves cover solid, shell, or line elements that describe the boundaries of the deformable bodies and are potentially in contact with the target surfaces defined by Target170, see Fig.11 .

[0076] Adjust the initial contact state, close the gaps and penetrations between the contact surfaces, and prevent the contact from affecting the calculation results of the contact stress due to the initial penetration. Fig.12 ,See Fig.13 .

[0077] 4. Calculation process and results

[0078] a. Calculate convergence

[0079] The calculation results are as follows. First check the entire calculation convergence process to ensure that the results are correct. Fig.14 As shown, the calculation process converges and completes the calculation.

[0080] The calculated Von-Mises stress is shown in Table 1 at the end of this article; the calculated displacement values ​​are shown in Table 2 at the end of this article; the calculated strain values ​​are shown in Table 3 at the end of this article. Fig.15 The stress nephogram is shown in Figure 1, and the displacement nephogram is shown in Figure 2. Fig.16 , strain cloud diagram see Fig.17 .

[0081] b. Sub-model calculation

[0082] The stress distribution can be better refined by using sub-model calculation. Fig.18 , and further verify the results. The stress calculation cloud diagram of the sub-model is shown in Fig.19 .

[0083] c. Calculate contact penetration and friction

[0084] To ensure accurate calculation, the penetration value needs to be controlled within a certain range. See the penetration value cloud diagram. Fig. 20 , the friction cloud diagram is shown in Fig.21 .

[0085] d. Calculate data summary

[0086] The final summary of all calculated values ​​is shown in 4-1.

[0087] Table 4-1 Calculation data summary table

[0088]

[0089] The maximum stress of the sub-model obtained in the table is 0.52% less than the standard 5% and the calculation is valid.

[0090] 5. Estimation of external fatigue cycle of the press roll

[0091] Based on the calculation of a fatigue analysis software, the following results are obtained. The roller surface that produces the maximum Von-mises stress is used for fatigue analysis. The life and damage are shown in Fig. 22 , Fig.23 , find the lowest point of life and make an estimate. The results are shown in Table 5-1.

[0092] Table 5-1 Summary data of fatigue analysis

[0093]

[0094] The above embodiments are only specific examples selected to illustrate the purpose, technical solutions and beneficial effects of the present invention in detail, but should not limit the scope of protection of the present invention. All modifications, equivalent substitutions and improvements made without violating the spirit and principles of the present invention should fall within the scope of protection of the present invention.

[0095] Appendix 1 Von-Mises calculated stress values

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[0105] Appendix 2 Displacement calculation values

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[0115] Appendix 3 Strain calculation values

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Claims

1. A method for analyzing the online cycle of a continuous casting machine sector guide roller based on finite element analysis, characterized in that: The following steps are involved: 1) Setting of relevant parameter boundary conditions: 1.

1. Establish a finite element mathematical model for a group of pressing rollers of the sector guide roller of the continuous casting machine; 1.

2. Collect relevant data of the continuous casting machine sector pressure roller, including motor speed, slab speed, slab temperature, slab size, drive roller diameter and material type; 1.

3. Use the material at 800℃ to simulate the dynamic behavior of the material during high temperature deformation. The physical parameters of the material used are density 7850kg / m3, Young's modulus 7.80E+10, Poisson's ratio 0.3, yield limit 1.40E+08 and tangent modulus 1.45E+09, and generate the material constitutive curve; 2) The augmented Lagrangian algorithm is used to theoretically analyze the nonlinear contact of the plastic deformation between the roller surface and the slab surface. The related analysis of plastic deformation uses the static mechanical analysis module. The principle formula of the augmented Lagrangian algorithm is: F normal = K normal ·X penetration +λ, and the iterative calculation is completed by artificially introducing the penetration amount and initial contact stiffness coefficient; 3) Mesh quality analysis: 3.

1. To ensure the convergence of nonlinear calculation and the accuracy of contact detection, the hexahedral Solid186 high-order unit is used as the finite element mathematical model, with a mesh quality coefficient > 0.74, warpage < 0.10, and a mesh quality Jacobi of 1.3; 3.

2. Determine the target unit and contact unit of the contact model. The contact model uses the Targer170 target unit and the Conta174 contact unit. Conta174 is used to represent the contact and sliding between the three-dimensional target surface and the deformable surface defined by the element, and to analyze the contact of the three-dimensional structure and the coupled field. 3.

3. Adjust the initial contact state, close the gaps and penetrations between the contact surfaces, and prevent the contact from affecting the calculation results of the contact stress due to the initial penetration; 4) Calculation process and results: 4.

1. First check the entire calculation convergence process to ensure that the results are correct. The calculation convergence curve can be used to know whether the calculation process has converged and the calculation is completed. The Von-Mises stress, displacement calculation value, strain calculation value, stress cloud map, displacement cloud map and strain cloud map are calculated; 4.

2. Using sub-models to verify the calculation can better refine the stress distribution and further verify the results; 4.

3. To ensure accurate calculation, the penetration amount needs to be controlled within a certain range, and the penetration value and friction force need to be calculated; 4.

4. Make a final summary of all calculated data, including displacement, strain, stress, penetration, friction stress, sub-model stress, and full model stress; 5) Estimation of external fatigue cycle of the press roller: Based on the calculation of fatigue analysis software, fatigue analysis is performed on the roller surface that produces the maximum Von-mises stress, and life cloud diagram and damage cloud diagram are generated to find the lowest point of life for estimation.

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