Ansys-based two-dimensional plunger type motor pump multi-rotor structure optimization method

Abstract

A two-dimensional plunger type motor pump multi-rotor structure optimization method based on Ansys comprises the steps that three-dimensional modeling software is used for establishing a parameterized structure model of a rotor structure, a steady-state structure model of the two-dimensional plunger type motor pump multi-rotor structure is established, and static strength and constraint modal analysis is conducted on the multi-rotor structure under the set working condition; setting a key design size of multiple rotors of the two-dimensional plunger type motor pump as a design variable definition, and establishing an optimization model by taking a simulation result as a constraint condition to optimize the key design size; selecting an optimization method to calculate to obtain a design variable value meeting a constraint condition; substituting the numerical rounding into the parameterized structure model and the steady-state structure analysis model to regenerate a structure model, and calculating to obtain an output parameter value; and if the output parameter value does not meet the constraint condition, adjusting the optimization parameter to obtain an optimization scheme. According to the multi-rotor structure, the size is reduced, the mass is reduced, the rigidity and the strength can still meet the requirements, and meanwhile the first-order inherent frequency is improved.

Description

Technical Field

[0001] The invention belongs to the field of motor pump component optimization, and specifically relates to a lightweight optimization method for a two-dimensional plunger motor pump multi-rotor structure based on Ansys. Background Art

[0002] The two-dimensional plunger motor pump is an integrated design of a two-dimensional plunger pump and a motor. The motor rotor drives the plunger shaft to rotate, and the spatial cam converts the rotational motion of the plunger shaft into a regular rotation plus translational motion, thereby realizing the oil suction and discharge of the two-dimensional plunger motor pump. The motor rotor, connector, plunger shaft, etc. constitute the multi-rotor structure of the two-dimensional plunger motor pump.

[0003] ANSYS software is a large-scale general-purpose finite element analysis (FEA) software and the fastest growing computer-aided engineering (CAE) software in the world. It can be used with most computer-aided designs. According to different application scenarios, through different simulation design methods, based on the assistance of ANSYS, a better structure can be obtained.

[0004] The existing two-dimensional plunger motor pump multi-rotor structure is large in size and heavy in weight. Summary of the invention

[0005] In order to overcome the shortcomings of the existing technology, the present invention provides a two-dimensional plunger motor pump multi-rotor structure optimization method based on Ansys. The volume of the multi-rotor structure is reduced, and then the mass is reduced. The stiffness and strength can still meet the requirements while the first-order natural frequency is improved.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A two-dimensional plunger motor pump multi-rotor structure optimization method based on Ansys, comprising the following steps;

[0008] 1) Use 3D modeling software to establish a parametric structural model of the rotor structure, build a simulation environment for data exchange between the 3D modeling software and Workbench, and import the 3D model into the Workbench working environment;

[0009] 2) Establish a steady-state structural model of a two-dimensional plunger motor pump multi-rotor structure in the Workbench working environment, and perform static strength analysis on the multi-rotor structure under set working conditions;

[0010] 3) According to the actual working conditions of the multi-rotor structure, constraints are imposed on the multi-rotor structure model to perform constrained modal analysis;

[0011] 4) According to the actual design requirements of the multi-rotor structure, the key design dimensions of the two-dimensional plunger motor pump multi-rotor are set as design variable definitions, and the optimization model is established to optimize the key design dimensions based on the simulation results in steps 2) and 3) as constraints;

[0012] 5) Select the optimization method, set the optimization parameters, call the parameterized structural model and optimization method to optimize the multi-rotor structure, and calculate the values ​​of the key dimensions δ1, δ2, and d within the constraints, that is, the target solution;

[0013] 6) Rounding the target solution data to meet actual production needs, substituting the data into the parameterized structural model and the steady-state structural analysis model, regenerating the structural model, and calculating the maximum stress value, maximum deformation value, and first-order natural frequency value;

[0014] 7) Output the new model to obtain the maximum stress value, maximum deformation value and first-order natural frequency value. If the values ​​do not meet the constraints, adjust the optimization parameters and repeat steps 5) and 6) until the requirements are met and the optimization solution is obtained.

[0015] The beneficial effects of the present invention are mainly manifested in: further optimizing the initial design dimensions of the multi-rotor structure of a two-dimensional plunger motor pump based on a multi-objective genetic algorithm. After the optimization using this method, the volume of the multi-rotor structure is reduced, and then the mass is reduced, while the stiffness and strength can still meet the requirements and the first-order natural frequency is improved. The lightweight design process and method can provide a reference for the lightweight design of other motor pump equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the multi-rotor structure of a two-dimensional plunger motor pump.

[0017] Figure 2 Schematic diagram of the key dimensions of the multi-rotor structure of a two-dimensional plunger motor pump.

[0018] Figure 3 It is a flow chart of the multi-rotor structure optimization method of two-dimensional plunger motor pump based on Ansys.

[0019] Explanation of the accompanying drawings: 1. First connector; 2. Second connector; 3. Motor rotor; 4. Plunger shaft; 5. Roller shaft; 6. Plunger sleeve. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings.

[0021] Reference Figure 1 to Figure 3 , a two-dimensional plunger motor pump multi-rotor structure optimization method based on Ansys, comprising the following steps;

[0022] 1) Based on 3D modeling software, such as Solidworks, use Solidworks to establish a parametric structural model of the rotor structure, build a simulation environment for data exchange between Solidworks and Workbench, and import the 3D model into the Workbench working environment;

[0023] 2) Establish a steady-state structural model of the multi-rotor structure of a two-dimensional plunger motor pump in the Workbench working environment, perform static strength analysis on the multi-rotor structure under set working conditions, and obtain the maximum deformation and maximum stress of the multi-rotor structure as constraints for subsequent optimization;

[0024]

[0025] Table 1

[0026] The assembled model is saved as a model file type in a general format such as .igs or x_t, and the model file is imported into the Ansys Workbench software to assign material properties to the two-dimensional piston motor pump multi-rotor structure model; then the Mesh module provided by the Ansys Workbench software is used to mesh the multi-rotor structure model. The mesh type is a tetrahedral mesh with a basic size of 2 mm, and the key surfaces of the model are locally encrypted; Table 1 is a table of material properties for each component.

[0027] Boundary condition settings: Set the motor rotor and coupler surfaces to contact, with the motor rotor surface as the contact surface and the coupler surface as the target surface. The contact type is Frictional, the friction coefficient is 0.1, the contact behavior is Asymmetric, and the contact calculation formula is Augmented Lagrange. The roller shaft and the plunger shaft are set as a fixed pair; the coupler and the plunger shaft are translation pairs; the overall bearing constraints are set. The bearings used in high-speed motors are generally high-speed rolling bearings, and their stiffness coefficient is 2x10 7 ~1x10 9 N / m. A distal displacement constraint is applied to the plunger shaft to simulate the movement of the plunger shaft in the axial direction, and a rotation speed of 8000r / min is applied to the plunger shaft;

[0028] After the boundary conditions are set, static structural analysis is performed on the multi-rotor structure to obtain the maximum displacement and maximum deformation values ​​of the rotor structure as subsequent constraint conditions;

[0029] 3) According to the actual working conditions of the multi-rotor structure, constraints are imposed on the multi-rotor structure model, and constrained modal analysis is performed to obtain the first-order natural frequency of the multi-rotor structure as the subsequent constraint conditions;

[0030] In the Workbench modal analysis system, the material properties, cell size and mesh division method of the multi-rotor structure are defined; the displacement of the element structure model at positions A and B is used to simulate the constraints of the bearing support. Since this simulation is a modal analysis, the first-order natural frequency value of the multi-rotor structure is solved.

[0031] Furthermore, the principle used in modal analysis is as follows: when analyzing the motor rotor, the rotor can be regarded as a linear free vibration system.

[0032] Its equation of motion is

[0033]

[0034] Where: [M], [C], [K] are the mass matrix, damping matrix, and stiffness matrix of the rotor system respectively; {x} are acceleration, velocity and displacement matrices respectively.

[0035] The natural frequency of the rotor structure is generally obtained by response without damping. The differential equation of motion of the rotor can be expressed as:

[0036]

[0037] The solution to the equation can be expressed as:

[0038] {x} = {x}e jω t (3) Substituting the general solution into equation (2) yields:

[0039] ([K] -ω 2 [M]){x}=0 (4) The solution of equation (4) is the natural frequency of the permanent magnet motor rotor, and the displacement vector corresponding to the eigenvalue of the equation is the mode vibration shape;

[0040] 4) Establish a parametric structural model of the multi-rotor structure of a two-dimensional plunger motor pump, and according to the actual design requirements of the multi-rotor structure, set the key design dimensions δ1, δ2, d of the multi-rotor structure as independent variables, take the maximum deformation and maximum stress of the rotor structure as constraints, minimize the mass and maximize the first-order natural frequency as optimization goals, and establish an optimization model to optimize the key design dimensions;

[0041] Taking the maximum deformation and maximum stress of the rotor structure as constraints, minimizing the mass and maximizing the first-order natural frequency as optimization goals, the mass M of the rotor structure is required to be as small as possible within the allowable range, and its first-order natural frequency f n1 As high as possible within the allowed range, construct two objective functions, namely:

[0042] F1(X)=minM(X); F2(X)=maxf n1 (5)

[0043] The mathematical model for optimizing the size of the multi-rotor structure of a two-dimensional plunger motor pump is:

[0044]

[0045] Where: δ1 is the side wall thickness; δ2 is the front wall thickness; d is the boss height; σ is the maximum stress; [σ e ] is the allowable stress; f n1 is the first-order natural frequency; F1(X) is the minimized mass; F2(X) is the maximum first-order natural frequency.

[0046] 5) Select the optimization method, set the optimization parameters, call the parameterized structural model and optimization method to optimize the multi-rotor structure, and calculate the values ​​of the key dimensions δ1, δ2, and d within the constraints, that is, the target solution;

[0047] According to the established multi-rotor structure size optimization model, the DesignExplorler optimization design module of AnsysWorkbench software is used to optimize the size of the multi-rotor structure of the two-dimensional piston motor pump based on the MOGA algorithm. The whole optimization process is shown in Figure 3 .

[0048] This algorithm is a variant of the non-dominated sorting genetic algorithm II, which is mostly used to solve the global minimum and maximum. The specific parameter settings of the optimization algorithm are as follows: the total population is 100; the crossover probability and mutation rate are 0.8 and 0.1 respectively; the maximum number of iterations is 40; the maximum number of candidate points is 3. At the same time, the anchor chain wheel mass function is minimized and the first-order frequency function is maximized, and the maximum stress is constrained to be less than the allowable stress value. The optimization iteration process converges with 80% of the samples distributed at the frontier of the Pareto solution set. Finally, after 40 iterations, a set of Pareto optimal solutions is obtained, and 3 sets of the most reasonable optimization design results are generated.

[0049] 6) Rounding the target solution data to meet actual production needs, substituting the data into the parameterized structural model and the steady-state structural analysis model, regenerating the structural model, and calculating the maximum stress value, maximum deformation value, and first-order natural frequency value;

[0050] 7) Output the new model to obtain the maximum stress value, maximum deformation value and first-order natural frequency value. If the values ​​do not meet the constraints, adjust the optimization parameters and repeat steps 5) and 6) until the requirements are met and the optimization solution is obtained.

[0051] As shown in Table 2, the initial structure and the three optimization schemes are compared. By comparing the three schemes, it can be found that the optimization scheme 2 is the most suitable for the goal of lightweight. In order to facilitate subsequent processing, the data of scheme 2 in Table 2 is rounded, and δ1=7mm, δ2=5mm, d=6mm are taken to re-model. Then, the optimized model is subjected to static structural analysis and constrained modal analysis, and the results are shown in Table 3, which is a comparison table of various performance parameters before and after optimization.

[0052] If the maximum stress value, maximum deformation value and first-order natural frequency value after analysis do not meet the constraint conditions, adjust the optimization parameters and repeat steps 5) and 6) until the requirements are met.

[0053]

[0054] Table 2

[0055]

[0056] Table 3

[0057] The optimization method and structure of the heavy-load lightweight multi-rotor structure based on ANSYS in this embodiment achieves the goal of reducing dead weight while ensuring the strength and stiffness of the structure. The volume of the optimized rotor structure is reduced by 15.1%. This means that through the optimized design, the size of the rotor structure becomes smaller, thereby reducing the weight of the entire rotor. This lightweight design meets the requirements of reducing weight while maintaining the strength and stiffness of the structure.

[0058] The contents described in the embodiments of this specification are merely enumerations of implementation forms of the inventive concept and are for illustrative purposes only. The protection scope of the present invention should not be considered to be limited to the specific forms described in this embodiment, and the protection scope of the present invention also extends to equivalent technical means that can be thought of by ordinary technicians in this field based on the inventive concept.

Claims

1. A two-dimensional plunger motor pump multi-rotor structure optimization method based on Ansys, characterized in that: The method comprises the following steps: 1) Use 3D modeling software to establish a parametric structural model of the rotor structure, build a simulation environment for data exchange between the 3D modeling software and Workbench, and import the 3D model into the Workbench working environment; 2) Establish a steady-state structural model of a two-dimensional plunger motor pump multi-rotor structure in the Workbench working environment, and perform static strength analysis on the multi-rotor structure under set working conditions; 3) According to the actual working conditions of the multi-rotor structure, constraints are imposed on the multi-rotor structure model to perform constrained modal analysis; 4) According to the actual design requirements of the multi-rotor structure, the key design dimensions of the two-dimensional plunger motor pump multi-rotor are set as design variable definitions, and the optimization model is established to optimize the key design dimensions based on the simulation results in step 2) and step 3) as constraints; 5) Select the optimization method, set the optimization parameters, call the parameterized structural model and the steady-state structural analysis model, perform optimization, and calculate the design variable values ​​that approach the target values, i.e., the target solution; 6) Substitute the target solution into the parameterized structural model and the steady-state structural analysis model, regenerate the structural model, and calculate the output parameter values; 7) Compare the output parameter value with the target value. If the error between the two does not meet the accuracy requirements, adjust the optimization parameters and repeat steps 5) and 6) until the accuracy meets the requirements and the optimization solution is obtained.

2. The two-dimensional plunger motor pump multi-rotor structure optimization method based on Ansys as claimed in claim 1, characterized in that: In the step 2), the assembled model is saved as a model file type in a general format, and the model file is imported into the Ansys Workbench software to assign material properties to the two-dimensional plunger motor pump multi-rotor structure model; then the multi-rotor structure model is meshed using the mesh module provided by the Ansys Workbench software, the mesh type is a tetrahedral mesh, the basic size is 2 mm, and the key surfaces of the model are locally encrypted; Boundary condition setting: Set the motor rotor and coupler surfaces as contact, the motor rotor surface as the contact surface, the coupler surface as the target surface, the contact type as Frictional, the friction coefficient as 0.1, the contact behavior as Asymmetric, and the contact calculation formula as Augmented Lagrange; the roller shaft and the plunger shaft are set as a fixed pair; the coupler and the plunger shaft are translation pairs; the bearing constraints are set as a whole, the bearings used in the high-speed motor are high-speed rolling bearings, and its stiffness coefficient is 2x107~1x109N / m; a distal displacement constraint is applied to the plunger shaft to simulate the movement of the plunger shaft in the axial direction, and a rotation speed of 8000r / min is applied to the plunger shaft; After the boundary conditions are set, the static structural analysis of the multi-rotor structure is carried out to obtain the total deformation displacement cloud map and equivalent stress cloud map of the rotor structure.

3. The two-dimensional plunger motor pump multi-rotor structure optimization method based on Ansys as claimed in claim 1 or 2, characterized in that: In the step 3), the material properties, cell size and meshing method of the multi-rotor structure are defined in the Workbench modal analysis system; The displacement of the position of the element structure model at A and B is used to simulate the constraint conditions of the bearing support. Since this simulation is a modal analysis, the first six vibration mode cloud diagrams of the multi-rotor structure are obtained by solving; The principles used in modal analysis are as follows, When analyzing the motor rotor, the rotor is regarded as a linear free vibration system, and its motion equation is: Where: [M], [C], [K] are the mass matrix, damping matrix, and stiffness matrix of the rotor system respectively; {x} are acceleration, velocity and displacement matrices respectively; The natural frequency of the rotor structure is obtained by the response without damping, and the differential equation of motion of the rotor is expressed as: The solution to the equation is expressed as: {x} = {x}e jω t (3) Substituting the general solution into equation (2) yields: ([K] -ω 2 [M]){x}=0 (4) The solution of equation (4) is the natural frequency of the permanent magnet motor rotor, and the displacement vector corresponding to the eigenvalue of the equation is the modal vibration shape.

4. The two-dimensional plunger motor pump multi-rotor structure optimization method based on Ansys as claimed in claim 1 or 2, characterized in that: In step 4), the maximum deformation and maximum stress of the rotor structure are used as constraints, and the minimization of mass and maximization of first-order natural frequency are used as optimization goals. The mass M of the rotor structure is required to be as small as possible within the allowable range, and its first-order natural frequency f is required to be as small as possible within the allowable range. n1 As high as possible within the allowed range, construct two objective functions, namely: F1(X)=minM(X);F2(X)=maxf n1 (5) The mathematical model for optimizing the size of the multi-rotor structure of a two-dimensional plunger motor pump is: Where: δ1 is the side wall thickness; δ2 is the front wall thickness; d is the boss height; σ is the maximum stress; [σ e ] is the allowable stress; f n1 is the first-order natural frequency; F1(X) is the minimized mass; F2(X) is the maximum first-order natural frequency.

5. The two-dimensional plunger motor pump multi-rotor structure optimization method based on Ansys as claimed in claim 1 or 2, characterized in that: In the step 5), according to the established multi-rotor structure size optimization model, the Design Explorer optimization design module of Ansys Workbench software is used to perform MOGA-based size optimization on the multi-rotor structure of the two-dimensional plunger motor pump; A variant algorithm of non-dominated sorting genetic algorithm II is used to solve the global minimum and maximum values. The optimization algorithm parameters are set as follows: the total population is 100; the crossover probability and mutation rate are 0.8 and 0.1 respectively; the maximum number of iterations is 40; the maximum number of candidate points is 3; the anchor chain wheel mass function is minimized and the first-order frequency function is maximized, and the maximum stress is constrained to be less than the allowable stress value. The optimization iterative process converges with 80% of the samples distributed at the frontier of the Pareto solution set. Finally, after 40 iterations, a set of Pareto optimal solutions is obtained, and 3 sets of the most reasonable optimization design results are generated.

6. The two-dimensional plunger motor pump multi-rotor structure optimization method based on Ansys as claimed in claim 1 or 2, characterized in that: In the step 7), the three groups of output parameter values ​​are compared with the target values. If the error of one group of output parameter values ​​is the smallest and meets the accuracy requirement of ±5%, it is the target solution; if all three groups of errors do not meet the accuracy requirement, the optimization parameters are adjusted and steps 5) and 6) are repeated until the accuracy meets the requirement.

Images