High-speed circuit breaker transmission system crank arm design method based on topological optimization

Abstract

The invention discloses a high-speed circuit breaker transmission system crank arm design method based on topological optimization, and belongs to the technical field of circuit breaker mechanical parts. Establishing an initial structure model of the crank arm by using software; importing the initial structure model of the crank arm into finite element analysis software, performing mesh generation on the initial structure model of the crank arm, and establishing a finite element model of topological optimization density of the crank arm; simulating the motion load of the crank arm, and setting the boundary condition of the finite element model of the topological optimization density of the crank arm; the method comprises the steps of determining an optimization area of a finite element model of topological optimization density of a crank arm, establishing a topological optimization mathematical model of the crank arm, performing calculation by utilizing a finite element analysis method and a topological optimization algorithm to obtain an optimized crank arm structure model, and taking the crank arm structure model meeting design requirements as a final crank arm improved structure by combining an actual process. Structural design is carried out based on the continuum structure topological optimization method, so that the optimal design scheme of the structural member can be quickly obtained, the design efficiency is improved, and the design period is shortened.

Description

Technical Field

[0001] The invention belongs to the technical field of circuit breaker mechanical parts, and in particular relates to a topology optimization-based crank arm design method for a high-speed circuit breaker transmission system. Background Art

[0002] High-speed circuit breakers can quickly adjust the topology of the power grid and achieve flexible suppression of short-circuit current. During the operation of high-speed circuit breakers, the crank arm of the transmission system is subjected to huge loads and impacts, so its structural strength and stiffness are crucial. Traditional crank arms are usually optimized based on experience or simple mathematical models, and there are problems such as structural unevenness, stress concentration, and energy loss, which limit the working efficiency and reliability of the transmission system. Compared with traditional optimization methods, topological optimization methods have global optimization capabilities, can improve structural performance, achieve multi-objective optimization and automated design processes, and provide a better solution for the design of crank arms of high-speed circuit breaker transmission systems. Therefore, a topological optimization design method for crank arm components is needed to improve their structural performance and working efficiency. Summary of the invention

[0003] The technical problem to be solved by the present invention is to propose a crank arm design method for a high-speed circuit breaker transmission system based on topology optimization in view of the above-mentioned deficiencies in the prior art, so as to improve the structural performance and working efficiency of the crank arm components.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] Step 1: Use software to establish the initial structural model of the crank arm;

[0006] Step 2: Import the initial structural model of the crank arm into the finite element analysis software, mesh the initial structural model of the crank arm, and establish a finite element model of the topological optimization density of the crank arm, with each mesh unit after division serving as the minimum unit with variable density;

[0007] Step 3 simulates the crank arm motion load and sets the boundary conditions of the finite element model of the topological optimization density of the crank arm;

[0008] Step 4 determines the optimization area of ​​the finite element model of the topological optimization density of the crank arm and takes the cell density of each grid in the optimization area as the optimization variable, takes the maximum stiffness and minimum volume as the optimization goals, establishes the topological optimization mathematical model of the crank arm and uses the finite element analysis method and the topological optimization algorithm to carry out calculations to obtain the optimized crank arm structure model, and combines the actual process to take the crank arm structure model that meets the design requirements as the final crank arm improved structure.

[0009] Furthermore, according to a design method of a crank arm of a high-speed circuit breaker transmission system based on topology optimization, the topology optimization mathematical model of the crank arm is:

[0010]

[0011] Among them, c(x,u) is the compliance, that is, the objective function of topology optimization; x is the unit density; u is the displacement vector; f is the load vector; u e is the displacement matrix of unit e; x e is the unit density of unit e; k0 is the unit stiffness matrix; υ e is the volume variable corresponding to unit e; V is the volume constraint variable; x max is the maximum value of the cell density, which takes the value of 1; x min is the minimum cell density.

[0012] Furthermore, according to a design method for a high-speed circuit breaker transmission system crank arm based on topology optimization, the initial structural model of the crank arm includes a main shaft hole, four bushing holes and upper and lower connecting rods. The four bushing holes are hingedly connected to the upper and lower connecting rods to form a transmission system structure that rotates around the main shaft hole of the crank arm.

[0013] Further, according to the method for designing a crank arm of a high-speed circuit breaker transmission system based on topology optimization, the boundary condition is a force of a given input specification.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention proposes a design method for a crank arm of a high-speed circuit breaker transmission system based on topological optimization. The initial design adopts a topological structure optimization method, which is independent of the original structure and the experience of engineers, has a high degree of design freedom, and can obtain an innovative physical structure. The crank arm structure is further designed on the basis of the initial structure obtained by topological optimization, which ensures that the structural strength is sufficiently high while minimizing the overall mass, thereby saving material costs compared with traditional crank arms. The lightweight design of the crank arm structure reduces the mass of the entire transmission system, thereby reducing the mechanical load of the operating mechanism and reducing the required operating work. The structural design is performed based on the continuum structure topological optimization method, and the optimal design scheme of the structural parts can be quickly obtained, thereby improving the design efficiency and shortening the design cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flow chart of a method for designing a crank arm of a high-speed circuit breaker transmission system based on topology optimization in an embodiment of the present invention;

[0017] Figure 2 This is a schematic diagram of the initial structure of the crank arm in an embodiment of the present invention;

[0018] Figure 3 A schematic diagram of topology optimization mesh generation and space setting in an embodiment of the present invention;

[0019] Figure 4 It is a planar topological structure diagram of the optimization result in the present invention;

[0020] Figure 5 It is the stress distribution diagram of the optimization result in the present invention. DETAILED DESCRIPTION

[0021] The invention will be further described below with reference to the accompanying drawings and specific implementation examples.

[0022] In this embodiment, a method for designing a crank arm of a high-speed circuit breaker transmission system based on topology optimization is provided. Figure 1 As shown, the following steps are included:

[0023] Step 1 uses software to establish an initial structural model of the crank arm; the initial structural model of the crank arm includes a main shaft hole, four bushing holes and upper and lower connecting rods, and the four bushing holes are hingedly connected to the upper and lower connecting rods to form a transmission system structure that rotates around the main shaft hole of the crank arm.

[0024] In this embodiment, three-dimensional CAD software is used to create Figure 2 The initial structural model of the crank arm is shown.

[0025] Step 2: Import the initial structural model of the crank arm into the finite element analysis software, mesh the initial structural model of the crank arm, and establish a finite element model of the topological optimization density of the crank arm, with each mesh unit after division serving as the minimum unit with variable density;

[0026] In this embodiment, the crank arm design space is subdivided into Figure 3 A grid of several regular square elements is shown.

[0027] Step 3 simulates the crank arm motion load and sets the boundary conditions of the finite element model of the topological optimization density of the crank arm;

[0028] The given input specification force is used as a boundary condition and applied to the nodes of the finite element model of the topological optimization density of the crank arm. In this embodiment, Figure 3 As shown, leftward and downward forces are applied respectively in the middle of the upper and lower bushing holes in the design space of the crank arm.

[0029] Step 4: Determine the optimization area of ​​the finite element model of the topological optimization density of the crank arm and use the cell density of each grid in the optimization area as the optimization variable, take the maximum stiffness and the minimum volume as the optimization target, establish the topological optimization mathematical model of the crank arm and use the finite element analysis method and the topological optimization algorithm to carry out the calculation, obtain the optimized crank arm structure model, and combine the actual process to use the crank arm structure model that meets the design requirements as the final crank arm improved structure;

[0030] In this embodiment, the other parts of the finite element model of the topological optimization density of the crank arm except the main shaft hole and the four bushing holes are used as the optimization area.

[0031] In this embodiment, a topology optimization mathematical model of the crank arm is constructed based on the SIMP theory, so that each unit in the optimization area is associated with a density-related continuous function, and the value range of the associated function is limited to 0-1. The density of the unit is associated with the elastic modulus in a certain relationship, and the formula is as follows:

[0032] E i =x j E0

[0033] Among them, E i is the penalty function of the i-th unit; x is the unit density, j is the penalty factor; E0 is the material elastic modulus.

[0034] The topology optimization mathematical model is as follows:

[0035]

[0036] Among them, c(x,u) is the compliance, that is, the objective function of topology optimization; x is the unit density; u is the displacement vector; f is the load vector; u e is the displacement matrix of unit e; x e is the unit density of unit e; k0 is the unit stiffness matrix; υ e is the volume variable corresponding to unit e; V is the volume constraint variable; x max is the maximum value of the cell density, which takes the value of 1; x min It is the minimum value of unit density. To prevent the occurrence of stiffness singularity, the value is 0.0001.

[0037] The optimization criterion for defining the objective function is the total strain energy of the crutch structure, which is equal to the work done when the load is applied. The relative density of the optimization area is used as the design variable, the volume ratio is used as the constraint condition, and the minimum strain energy is used as the optimization goal. The total strain energy is equal to the work done when the load is applied, so minimizing the strain energy is equivalent to maximizing the stiffness.

[0038] like Figure 4 , Figure 5 As shown in the figure, through the topological optimization analysis of the initial model of the crank arm, the lightweight design of the crank arm is achieved. According to the stiffness requirements of the crank arm, the maximum stress value of the optimized crank arm is 421.8MPa, which is less than the allowable stiffness standard.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the claims of the present invention.

Claims

1. A method for designing a crank arm of a high-speed circuit breaker transmission system based on topology optimization, characterized in that: The following steps are involved: Step 1: Use software to establish the initial structural model of the crank arm; Step 2: Import the initial structural model of the crank arm into the finite element analysis software, mesh the initial structural model of the crank arm, and establish a finite element model of the topological optimization density of the crank arm, with each mesh unit after division serving as the minimum unit with variable density; Step 3 simulates the crank arm motion load and sets the boundary conditions of the finite element model of the topological optimization density of the crank arm; Step 4 determines the optimization area of ​​the finite element model of the topological optimization density of the crank arm and takes the cell density of each grid in the optimization area as the optimization variable, takes the maximum stiffness and minimum volume as the optimization goals, establishes the topological optimization mathematical model of the crank arm and uses the finite element analysis method and the topological optimization algorithm to carry out calculations to obtain the optimized crank arm structure model, and combines the actual process to take the crank arm structure model that meets the design requirements as the final crank arm improved structure.

2. The method for designing a crank arm of a high-speed circuit breaker transmission system based on topology optimization according to claim 1, characterized in that: The topological optimization mathematical model of the crank arm is: Among them, c(x,u) is the compliance, that is, the objective function of topology optimization; x is the unit density; u is the displacement vector; f is the load vector; u e is the displacement matrix of unit e; x e is the unit density of unit e; k0 is the unit stiffness matrix; υ e is the volume variable corresponding to unit e; V is the volume constraint variable; x max is the maximum value of the cell density, which takes the value of 1; x min is the minimum cell density.

3. The method for designing a crank arm of a high-speed circuit breaker transmission system based on topology optimization according to claim 1, characterized in that: The initial structural model of the crank arm includes a main shaft hole, four bushing holes and upper and lower connecting rods. The four bushing holes are hingedly connected with the upper and lower connecting rods to form a transmission system structure rotating around the main shaft hole of the crank arm.

4. The method for designing a crank arm of a high-speed circuit breaker transmission system based on topology optimization according to claim 1, characterized in that: The boundary conditions are forces given the input specifications.

Images