Method for optimizing boss structure of elastic ring type squeeze film damper

Abstract

The invention relates to the technical field of aero-engines, in particular to a boss structure optimization method for an elastic ring type squeeze film damper, which comprises the following steps: acquiring an oil film gap of the damper; corresponding circumferential relative oil film force and radial relative oil film force of the damper under different eccentric ratios are obtained; obtaining multiple groups of optimization parameters; constructing a constraint function and a target function; and obtaining an optimal optimization parameter, and obtaining an optimized boss structure. According to the optimization method, the influence of the boss height and the boss width on the circumferential relative oil film force and the radial relative oil film force is considered, and the purposes of improving the circumferential relative oil film force of the damper and reducing the radial relative oil film force of the damper are taken as targets, so that the optimized boss structure can increase the oil film damping, enhance the vibration reduction characteristic and reduce the oil film rigidity; and the influence of the damper additional rigidity on the critical rotating speed is weakened.

Description

Technical Field

[0001] The invention relates to the technical field of aero-engines, and in particular to a method for optimizing the boss structure of an elastic ring type squeeze film damper. Background Art

[0002] As aviation demands for aircraft maneuverability and engine thrust-to-weight ratios continue to rise, aircraft engines are subject to high speeds, high temperatures, high loads, complex and variable operating conditions, and complex yet lightweight structures. This has led to increasingly prominent vibration issues, making them nearly impossible to avoid. As a key bottleneck in the development of the aviation industry, engine vibration reduction design has become a core challenge that must be overcome in the development of next-generation engines.

[0003] To effectively suppress vibration in aircraft engine rotor systems, dampers are commonly installed at the fulcrum. Squirrel-cage squeeze film dampers (SFDs) and elastic ring squeeze film dampers (ERSFDs) have been widely used due to their significant vibration reduction performance. However, when operating under complex conditions such as high speed and heavy load, traditional SFDs often experience bistability and uncoordinated precession due to the highly nonlinear oil film properties. This not only causes excessive rotor vibration but also exacerbates friction and fatigue, increasing the risk of failure. In contrast, ERSFDs demonstrate significant advantages in improving oil film stiffness nonlinearity, enhancing adaptability to system parameter changes, and conserving engine axial space. ERSFDs have been successfully employed for frequency modulation and vibration control in foreign engines such as the AM-24, AM-25, and AJI-31.

[0004] In existing research, such as the study of the vibration reduction mechanism of elastic ring squeeze film damper, the deformation equation and oil film control equation of the elastic ring squeeze film damper were proposed, and the pressure field was solved by finite difference. In the "Theoretical and Experimental Study of the Dynamic Characteristics of a Two-Phase Flow Squeeze Film Damper-Rotor System," it was proposed that the elastic ring deforms under the action of the oil film force, affecting the contact state of the boss. In the "Influence of the Fit Relationship on the Vibration Damping Characteristics of an Elastic Ring Squeeze Film Damper," a rotor experimental system with an ERSFD was constructed, and the influence of the fit relationship between the elastic ring and the bushing on the vibration damping performance of the elastic ring squeeze film damper was experimentally studied. The prior art also proposed an ERSFD coupling model that considers fit tightness, studying the influence of fit tightness on ERSFD parameters and the dynamic characteristics of the rotor system. A test device for the dynamic characteristics of an elastic ring squeeze film damper was proposed that can effectively measure the dynamic characteristics of the elastic ring, including the static stiffness of the elastic ring, the oil film stiffness of the elastic ring squeeze film damper, and the oil film damping. Furthermore, a design method for a simulation tester with an elastic ring squeeze film damper was proposed in the prior art. This method uses the dynamic similarity criterion to perform full-scale scale design, providing a new approach to the design of rotor simulation testers.

[0005] In summary, while significant progress has been made in ERSFD research, research on damper structural optimization methods remains relatively scarce. In particular, key structural parameters, such as boss height and width, exhibit nonlinear effects on the ERSFD's oil film damping characteristics. However, existing technologies lack effective parameter optimization methods, leading to significant design errors.

[0006] Therefore, it is necessary to provide a method for optimizing the boss structure of an elastic ring type squeeze film damper to solve the above problems. Summary of the Invention

[0007] The problem that an effective parameter optimization method has not been established in the prior art, resulting in a large degree of blindness in the design process, has not been solved. The present invention provides a boss structure optimization method for an elastic ring type squeeze film damper.

[0008] The present invention provides a method for optimizing the boss structure of an elastic ring type squeeze film damper, which adopts the following technical solutions, including: Applying different bearing loads to the damper in sequence to obtain deformation parameters of the damper under the different bearing loads, and obtaining the oil film clearance of the damper based on the deformation parameters of the damper, wherein the deformation parameters of the damper include: static eccentric displacement of the inner bushing of the elastic ring, directional displacement of the oil film surface of the inner bushing of the elastic ring, directional displacement of the inner oil film surface of the elastic ring, directional displacement of the outer oil film surface of the elastic ring, and directional displacement of the oil film surface of the outer bushing of the elastic ring; The oil film gap is used as the input parameter, and the generalized Reynolds equation is used to obtain the oil film dynamic characteristics. The finite difference method is used to solve the oil film pressure field. The circumferential relative oil film force and radial relative oil film force corresponding to the damper at different eccentricity ratios are obtained by integrating the oil film pressure field. The boss width, inner boss height and outer boss height of the elastic ring are used as optimization parameters of the boss structure, and multiple groups of optimization parameters are obtained by selecting optimization parameters within a preset optimization parameter range; A constraint function is constructed based on the elastic ring stiffness before and after optimization of each set of optimization parameters, and an objective function is constructed based on the circumferential relative oil film force and radial relative oil film force of the damper; Based on the constraint function and the objective function, the best optimization parameters among all groups of optimization parameters are obtained by using an optimization algorithm; the boss structure is optimized according to the best optimization parameters to obtain an optimized boss structure.

[0009] Preferably, the steps of sequentially applying different bearing loads to the damper are: Determine the structural dimensions of the elastic ring in combination with the rotor structure, establish a three-dimensional model of the elastic ring based on the determined structural parameters of the elastic ring, and establish a three-dimensional model of the inner and outer bushings that match the inner and outer bosses of the elastic ring; Assembling the elastic ring three-dimensional model, the inner bushing three-dimensional model and the outer bushing three-dimensional model to form a damper; A radial force is applied to the inner surface of the three-dimensional model of the damper's inner bushing to simulate the bearing load and then applied to the damper.

[0010] Preferably, the step of obtaining the oil film clearance of the damper according to the deformation parameters of the damper is: The steps of obtaining the oil film clearance of the damper according to the deformation parameters of the damper are as follows: obtaining the journal eccentricity of the damper under each bearing load according to the static eccentric displacement of the bushing in the elastic ring, and obtaining the eccentricity ratio of the damper under each bearing load according to the journal eccentricity and the oil film thickness of the damper under the bearing load; According to the directional displacement and coordinates corresponding to the grid nodes on the inner oil film surface of the elastic ring three-dimensional model and the directional displacement and coordinates corresponding to the grid nodes on the oil film surface of the inner sleeve three-dimensional model, the relative distance between the inner oil film surface of the elastic ring and the oil film surface of the inner sleeve of the damper under each eccentricity ratio is obtained, and the relative distance between the inner oil film surface of the elastic ring and the oil film surface of the inner sleeve is used as the inner oil film gap; According to the directional displacements and coordinates corresponding to the grid nodes on the outer oil film surface of the elastic ring three-dimensional model and the directional displacements and coordinates corresponding to the grid nodes on the oil film surface of the outer bushing three-dimensional model, the relative distance between the outer oil film surface of the elastic ring three-dimensional model and the oil film surface of the outer bushing three-dimensional model of the damper under each eccentricity ratio is obtained, and the relative distance between the outer oil film surface of the elastic ring three-dimensional model and the oil film surface of the outer bushing three-dimensional model is used as the outer oil film gap; Among them, the oil film gap of the damper is divided into the outer oil film gap and the inner oil film gap.

[0011] Preferably, the oil film gap is used as an input parameter, and the oil film dynamic characteristics are obtained based on the generalized Reynolds equation. The steps of solving the oil film pressure field using the finite difference method are as follows: Based on the generalized Reynolds equation, the control equations corresponding to the inner ring oil film pressure field and the outer ring oil film pressure field of the damper elastic ring are derived; Based on the control equation, the oil film gap, journal eccentricity and node pressure values are non-dimensionalized to obtain the non-dimensionalized pressure field control equation of the elastic ring. The finite difference method is used to solve the dimensionless pressure field control equation of the elastic ring to obtain the oil film pressure field.

[0012] Preferably, the preset optimization parameter range includes: The optimized parameter range of the boss width is set according to the arc length of the substructure sandwiched between the center lines of adjacent inner bosses; The optimized parameter range of the boss height is set according to the average radius of the elastic ring.

[0013] Preferably, when selecting the optimization parameters, the height and value of the outer boss height and the inner boss height remain unchanged.

[0014] Preferably, the constraint function is expressed as:

[0015] Where, Indicates the The constraint function values corresponding to the group optimization parameters; represents the elastic ring stiffness before optimizing the boss structure; Indicates in Elastic ring stiffness after optimizing boss structure under the set optimization parameters; Represents evolutionary algebra.

[0016] Preferably, the objective function is expressed as:

[0017] Where, Indicates the The objective function value corresponding to the group optimization parameters; Indicates the The circumferential relative oil film force of the damper corresponding to the boss structure with the optimized parameters; Indicates the The boss structure with the optimized parameters corresponds to the radial relative oil film force of the damper.

[0018] Preferably, a particle swarm optimization algorithm is used to obtain the best optimization parameter among all groups of optimization parameters.

[0019] Preferably, the steps of obtaining the best optimization parameters among all groups of optimization parameters based on the constraint function and the objective function and using the optimization algorithm are: The corresponding set of optimization parameters when the constraint function is satisfied and the objective function value is maximized is taken as the best optimization parameters.

[0020] The beneficial effects of the present invention are: The present invention analyzes and finds that the influence of the boss height and width parameters on the ERSFD oil film damping characteristics exhibits nonlinear characteristics. Therefore, the present invention establishes an objective function based on the circumferential relative oil film force and radial relative oil film force corresponding to the damper at different eccentricity ratios, and constructs a constraint function based on the elastic ring stiffness before and after optimization. Then, based on the constraint function and the objective function, the optimization algorithm is used to obtain the best optimization parameters among all groups of optimization parameters, thereby obtaining the optimized boss structure. The optimization method of the present invention considers the influence of the boss height and boss width on the circumferential relative oil film force and radial relative oil film force, and aims to increase the circumferential relative oil film force of the damper and reduce the radial relative oil film force of the damper. The optimized boss structure can increase the oil film damping, enhance the vibration damping characteristics, reduce the oil film stiffness, and weaken the influence of the damper's additional stiffness on the critical speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A flowchart of an embodiment of a method for optimizing the boss structure of an elastic ring type squeeze film damper according to the present invention; Figure 2 Schematic diagram of the finite element analysis structure of the elastic ring structure before optimization in an embodiment of the present invention; Figure 3 Schematic diagram of the finite element analysis structure of the elastic ring structure optimized by the method of the present invention in an embodiment of the present invention; Figure 4 Schematic diagram comparing the oil film pressure fields corresponding to the elastic ring structures before and after optimization in an embodiment of the present invention; Figure 5 Schematic diagram comparing the equivalent oil film stiffness of the elastic ring structure before and after optimization in an embodiment of the present invention; Figure 6 Schematic diagram comparing the equivalent oil film damping corresponding to the elastic ring structure before and after optimization in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] An embodiment of a method for optimizing the boss structure of an elastic ring type squeeze film damper of the present invention is as follows: Figure 1 As shown, including: S1. Obtain the oil film clearance of the damper; Specifically, different bearing loads are applied to the damper in sequence, deformation parameters of the damper under different bearing loads are obtained, and the oil film clearance of the damper is obtained according to the deformation parameters of the damper.

[0025] Exemplarily, in a specific implementation, the steps of applying different bearing loads to the damper in sequence are: determining the structural dimensions of the elastic ring in combination with the rotor structure, establishing a three-dimensional model of the elastic ring according to the determined structural parameters of the elastic ring, and establishing a three-dimensional model of the inner sleeve and a three-dimensional model of the outer sleeve that match the inner boss and outer boss of the elastic ring; assembling the three-dimensional model of the elastic ring, the three-dimensional model of the inner sleeve and the three-dimensional model of the outer sleeve to form a damper; applying a radial force on the inner circular surface of the three-dimensional model of the inner sleeve of the damper to simulate the bearing load, and applying it to the damper.

[0026] Among them, the steps of applying radial force on the inner circular surface of the three-dimensional model of the inner sleeve of the damper are: importing the damper into ANSYS software for finite element analysis, setting the physical properties of the relevant materials of each model of the damper in ANSYS software (finite element analysis), and dividing the grid; because when the elastic ring of the damper is subjected to radial load and elastic deformation occurs, not all the inner bosses of the elastic ring and the inner sleeve of the elastic ring, and all the outer bosses of the elastic ring and the outer sleeve of the elastic ring always maintain fixed contact, the inner boss of the elastic ring and the inner sleeve of the elastic ring, and the outer boss of the elastic ring and the outer sleeve of the elastic ring in the direction opposite to the load are set to fixed contact, and the inner and outer bosses of the elastic ring and the inner and outer sleeves of the elastic ring in other directions are set to friction contact, the outer circular surface of the outer sleeve is fixed to constrain its displacement, and a radial force is applied to the inner circular surface of the three-dimensional model of the inner sleeve of the damper.

[0027] Exemplarily, in a specific implementation, the steps for obtaining the deformation parameters of the damper under different bearing loads are: applying different bearing loads to the damper in sequence in the finite element analysis software to obtain the deformation parameters of the damper, and the deformation parameters of the damper include: the static eccentric displacement of the inner sleeve of the elastic ring, the directional displacement of the oil film surface of the inner sleeve of the elastic ring, the directional displacement of the inner oil film surface of the elastic ring, the directional displacement of the outer oil film surface of the elastic ring, and the directional displacement of the oil film surface of the outer sleeve of the elastic ring.

[0028] For example, in a specific implementation, the steps of obtaining the oil film clearance of the damper according to the deformation parameters of the damper are as follows: obtaining the journal eccentricity of the damper under each bearing load according to the static eccentric displacement of the bushing in the elastic ring; obtaining the eccentricity ratio of the damper under each bearing load according to the journal eccentricity and oil film thickness of the damper under the bearing load. ε ,in, ε = e / c ,in c is the oil film thickness, ε is the journal eccentricity ratio, according to the directional displacement and coordinates corresponding to the grid nodes on the inner oil film surface of the elastic ring three-dimensional model and the directional displacement and coordinates corresponding to the grid nodes on the oil film surface of the inner sleeve three-dimensional model, the relative distance between the inner oil film surface of the elastic ring and the oil film surface of the inner sleeve of the damper under each eccentricity ratio is obtained, and the relative distance between the inner oil film surface of the elastic ring and the oil film surface of the inner sleeve is taken as the inner oil film gap; according to the directional displacement and coordinates corresponding to the grid nodes on the outer oil film surface of the elastic ring three-dimensional model and the directional displacement and coordinates corresponding to the grid nodes on the oil film surface of the outer sleeve three-dimensional model, the relative distance between the outer oil film surface of the elastic ring three-dimensional model and the oil film surface of the outer sleeve three-dimensional model of the damper under each eccentricity ratio is obtained, and the relative distance between the outer oil film surface of the elastic ring three-dimensional model and the oil film surface of the outer sleeve three-dimensional model is taken as the outer oil film gap; wherein, the oil film gap of the damper is the outer oil film gap h out and internal oil film clearance h in .

[0029] At this point, the oil film clearance of the damper under different eccentricity ratios can be obtained.

[0030] S2. Obtain the circumferential relative oil film force and radial relative oil film force corresponding to the damper at different eccentricity ratios; Specifically, the oil film gap is used as the input parameter, and the generalized Reynolds equation is used to obtain the oil film dynamic characteristics. The finite difference method is used to solve the oil film pressure field, and the oil film pressure field is integrated to obtain the circumferential relative oil film force and radial relative oil film force corresponding to the damper at different eccentricity ratios.

[0031] For example, in a specific implementation, the oil film gap is used as an input parameter, and the oil film dynamic characteristics are obtained based on the generalized Reynolds equation. The steps of using the finite difference method to solve the oil film pressure field are as follows: based on the generalized Reynolds equation, the control equations corresponding to the inner ring oil film pressure field and the outer ring oil film pressure field of the elastic ring of the damper are derived; based on the control equations, the oil film gap, the journal eccentricity, and the node pressure value are non-dimensionalized to obtain the non-dimensionalized pressure field control equation of the elastic ring; the finite difference method is used to solve the non-dimensionalized pressure field control equation of the elastic ring to obtain the oil film pressure field. Among them, based on the generalized Reynolds equation, the control equations corresponding to the inner ring oil film pressure field and the outer ring oil film pressure field of the elastic ring are derived; among them, the control equation of the inner ring oil film pressure field is:

[0032] The governing equation of the outer ring oil film pressure field is:

[0033] Where, is the oil film radius; is the angular coordinate; is the oil film pressure; is the axial coordinate; is the oil film viscosity; is the journal eccentricity; is the journal precession velocity; is the net flow rate of lubricating oil at the oil seepage hole; For time.

[0034] Introducing parameters H = h / c 、 ε = e / c and p =2 ΩμR 2 P / c 2 , for oil film clearance h , journal eccentricity e and node pressure values p Non-dimensionalization is performed, where c is the oil film thickness, ε is the journal eccentricity ratio. The dimensionless pressure field control equation of the elastic ring is:

[0035] The finite difference method is used to solve the pressure field control equation of the dimensionless elastic ring to obtain the oil film pressure field, that is, the oil film segment is divided into several grids, and the pressure value on each node is used to form each order difference quotient. During the calculation process, the initial value of the iterative pressure field can be stipulated to be equal to the boundary pressure value to form an initial pressure field matrix, and the initial value of the pressure iteration of each node is determined respectively. The new node pressure can be obtained by traversing all nodes through the four node pressures around each node, the oil film gap of the half node, and the speed of change of the node oil film gap. The pressure field iteration value can be obtained. The iterative process is repeated until the error of all nodes is less than the error limit, and the solution of the oil film pressure field is completed. Specifically, in this embodiment, the oil film is meshed, and the oil film segment is divided into multiple grids. The pressure values on each node of the grid and the nodes around it are used, starting from the first node. i Starting from the oil film segment, the initial pressure amplitude of each grid node is set to 0Pa, and the new first pressure amplitude is obtained after the finite difference method is used to calculate once. i The pressure distribution of the oil film segment, at the same time, the new pressure value at the oil seepage hole of this oil film is also obtained; i and the adjacent oil film segment on the other side i+ 1 is assigned to the oil seepage hole of the adjacent oil film segment on the other side. When all the oil film segments are calculated once in a week, one iteration is completed. The iterative calculation is continued until the pressure difference with the previous iteration is less than the error limit. The pressure distribution field calculation of all the oil film segments is completed, and the oil film pressure field can be obtained.

[0036] At this point, the oil film pressure field can be integrated to obtain the circumferential relative oil film force and radial relative oil film force corresponding to the damper at different eccentricity ratios.

[0037] It should be noted that the equivalent oil film stiffness of the elastic ring squeeze film damper is K 0 and equivalent oil film damping C 0 respectively by radial force F r and tangential force F t Determine, the expression is:

[0038]

[0039] Where, The eccentricity of the journal; is the journal precession velocity, and the equivalent oil film stiffness and equivalent oil film damping corresponding to the circumferential relative oil film force and radial relative oil film force under different bearing loads can be obtained. The stiffness characteristic curve of the damper can be obtained based on the equivalent oil film stiffness of the damper under different eccentricity ratios, and the damping characteristic curve can be obtained based on the equivalent oil film damping of the damper under different eccentricity ratios.

[0040] S3. Obtain multiple sets of optimization parameters; Specifically, the boss width, inner boss height, and outer boss height of the elastic ring are used as optimization parameters of the boss structure, and multiple groups of optimization parameters are obtained by selecting optimization parameters within a preset optimization parameter range.

[0041] For example, in a specific implementation, when the rotor system has been finalized, most of the structural dimensions of the elastic ring squeeze film damper cannot be changed, and there are fewer design parameters to choose from. At this time, only individual components may be able to be optimized, such as the boss width and boss height of the damper elastic ring. Therefore, in this embodiment, the boss width, inner boss height and outer boss height of the elastic ring are used as optimization parameters of the boss structure.

[0042] For example, in a specific embodiment, the optimization parameters of the elastic ring boss include boss width b , inner boss height c 1 and outer boss height c 2. The optimization parameter range of the boss width is 25%~50% of the arc length of the substructure sandwiched between the center lines of adjacent inner bosses (or adjacent outer bosses), and the optimization parameter range of the boss height is 2‰~6‰ of the average radius of the elastic ring.

[0043] For example, in a specific implementation, the steps of selecting optimization parameters within the preset optimization parameter range to obtain multiple sets of optimization parameters are as follows: the value of the boss width b is: all values between the lower limit value and the upper limit value of the optimization parameter range of the boss width are selected; the inner boss height is c 1 and outer boss height c 2 values are: all values between the lower limit and upper limit of the optimization parameter range of the boss height are selected; it should be noted that the boss height c 2 and inner boss height c The value of 1 satisfies: the height of the outer boss c 2 and inner boss height c 1. The height and value remain unchanged, and the selected boss width b and inner boss height c 1. Height of outer boss c By combining all values of 2 one by one, we can get multiple sets of optimization parameters.

[0044] It should be noted that by combining the non-adjustable parameters of the elastic ring (including the number of bosses m; the axial length of the elastic ring L; the elastic modulus E; the inner diameter D1 of the elastic ring, the outer diameter D2 of the elastic ring, the ring segment thickness s, and the fillet diameter d of the boss root) with each set of optimization parameters, elastic ring structures with multiple sets of optimization parameters can be obtained. Based on steps S1-S2, the fitting curves of the circumferential relative oil film force and the radial relative oil film force of the damper corresponding to the elastic ring structure with each set of optimization parameters under different eccentricity ratios can be obtained. Based on the fitting curves corresponding to the circumferential relative oil film force and the radial relative oil film force, the stiffness characteristic curve and the damping characteristic curve can be further obtained.

[0045] S4. Construct constraint function and objective function; Specifically, a constraint function is constructed based on the elastic ring stiffness before and after optimization of each set of optimization parameters, and an objective function is constructed based on the circumferential relative oil film force and radial relative oil film force of the damper.

[0046] For example, in one specific implementation, the objectives of the boss structure optimization design of the elastic ring type squeeze film damper include: (1) increasing the circumferential oil film force of the damper, increasing the oil film damping, and thus enhancing the vibration reduction characteristics; (2) reducing the radial oil film force of the damper, reducing the oil film stiffness, and weakening the effect of the damper's additional stiffness on the critical speed. During the optimization operation of the damper boss structure, the elastic ring stiffness change is not greater than 20% as a constraint condition.

[0047] For example, in a specific embodiment, the constraint function is expressed as:

[0048] Where, Indicates the The constraint function values corresponding to the group optimization parameters; represents the elastic ring stiffness before optimizing the boss structure; Indicates in Elastic ring stiffness after optimizing boss structure under the set optimization parameters; Represents evolutionary algebra.

[0049] For example, in a specific embodiment, the objective function is expressed as:

[0050] Among them, this function represents the objective function for optimizing the oil film vibration reduction characteristics of the elastic ring squeeze film damper. In this embodiment, a small eccentricity ratio ( =0.3) is the optimization target, Indicates the The objective function value corresponding to the group optimization parameters; Indicates the The circumferential relative oil film force of the damper corresponding to the boss structure with the optimized parameters; Indicates the The boss structure with the optimized parameters corresponds to the radial relative oil film force of the damper.

[0051] S5, obtaining the best optimization parameters and obtaining the optimized boss structure; Specifically, based on the constraint function and the objective function, the optimal optimization parameters among all groups of optimization parameters are obtained by using an optimization algorithm; and the boss structure is optimized according to the optimal optimization parameters to obtain an optimized boss structure.

[0052] For example, in a specific implementation, the optimization algorithm adopts a particle swarm algorithm. The performance of the particle swarm algorithm depends on the calculation speed of a single particle fitness, the size of the particle population, and the evolutionary generation. Taking into account the number of optimization parameters and computer performance, the population number is selected as 50 and the number of iterations is 20. The corresponding set of optimization parameters when the constraint function is satisfied and the objective function value is maximized is used as the optimal optimization parameters. The boss structure is optimized based on the optimal optimization parameters to obtain the optimized boss structure.

[0053] The present embodiment is described below with reference to the accompanying drawings and specific simulation data: The boss structure optimization of a certain type of elastic ring squeeze film damper is carried out. Following the optimization implementation process, the parameters of the elastic ring structure before and after optimization are shown in Table 1.

[0054] Table 1

[0055] First, check whether the elastic ring stiffness of the optimized structure meets the stiffness constraint conditions, and perform finite element analysis on the elastic ring structure before optimization to obtain the following: Figure 2 The analysis structure shown in the figure is shown in the figure. The finite element analysis of the optimized elastic ring structure is carried out to obtain the following Figure 3 The analysis structure shown. Taking the bearing load of 100N as an example, the elastic ring stiffness expression is calculated as follows: The elastic ring stiffness before optimization is

[0056] The optimized elastic ring stiffness is

[0057] Satisfy stiffness constraints; Secondly, the oil film characteristics of the elastic ring structure before and after optimization are solved respectively. The pressure field distribution results of the elastic ring structure before and after optimization are compared based on the finite difference method. Figure 4As shown in the figure, the corresponding pressure fields before and after optimization are integrated respectively to obtain the circumferential relative oil film force and radial relative oil film force corresponding to the eccentricity ratio of the bearing load under 100N.

[0058] Finally, based on the circumferential relative oil film force, we can obtain Figure 5 The stiffness characteristic curve corresponding to the elastic ring shown in the figure is as follows; based on the radial relative oil film force, the following is obtained: Figure 6 The damping characteristic curve corresponding to the elastic ring shown in the figure verifies the optimization effect of the elastic ring type squeeze oil film after the optimization of the elastic ring structure. Figure 5 As shown in Figure 2, the equivalent oil film stiffness of the optimized structure is significantly lower than that of the structure before optimization. Figure 6 The equivalent oil film damping of the optimized structure is significantly improved compared with the structure before optimization, that is, the optimized structure meets the optimization index requirements, and the optimization method has high effectiveness and feasibility.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for optimizing the boss structure of an elastic ring type squeeze film damper, characterized in that: include: Applying different bearing loads to the damper in sequence to obtain deformation parameters of the damper under the different bearing loads, and obtaining the oil film clearance of the damper based on the deformation parameters of the damper, wherein the deformation parameters of the damper include: static eccentric displacement of the inner bushing of the elastic ring, directional displacement of the oil film surface of the inner bushing of the elastic ring, directional displacement of the inner oil film surface of the elastic ring, directional displacement of the outer oil film surface of the elastic ring, and directional displacement of the oil film surface of the outer bushing of the elastic ring; The oil film gap is used as the input parameter, and the generalized Reynolds equation is used to obtain the oil film dynamic characteristics. The finite difference method is used to solve the oil film pressure field. The circumferential relative oil film force and radial relative oil film force corresponding to the damper at different eccentricity ratios are obtained by integrating the oil film pressure field. The boss width, inner boss height and outer boss height of the elastic ring are used as optimization parameters of the boss structure, and multiple groups of optimization parameters are obtained by selecting optimization parameters within a preset optimization parameter range; A constraint function is constructed based on the elastic ring stiffness before and after optimization of each set of optimization parameters, and an objective function is constructed based on the circumferential relative oil film force and radial relative oil film force of the damper; Based on the constraint function and the objective function, the best optimization parameters among all groups of optimization parameters are obtained by using an optimization algorithm; the boss structure is optimized according to the best optimization parameters to obtain an optimized boss structure.

2. The method for optimizing the boss structure of an elastic ring type squeeze film damper according to claim 1, characterized in that: The steps for applying different bearing loads to the damper are: Determine the structural dimensions of the elastic ring in combination with the rotor structure, establish a three-dimensional model of the elastic ring based on the determined structural parameters of the elastic ring, and establish a three-dimensional model of the inner and outer bushings that match the inner and outer bosses of the elastic ring; Assembling the elastic ring three-dimensional model, the inner bushing three-dimensional model and the outer bushing three-dimensional model to form a damper; A radial force is applied to the inner surface of the three-dimensional model of the damper's inner bushing to simulate the bearing load and then applied to the damper.

3. The method for optimizing the boss structure of an elastic ring type squeeze film damper according to claim 1, characterized in that: The steps to obtain the oil film clearance of the damper according to the deformation parameters of the damper are: The steps of obtaining the oil film clearance of the damper according to the deformation parameters of the damper are as follows: obtaining the journal eccentricity of the damper under each bearing load according to the static eccentric displacement of the bushing in the elastic ring, and obtaining the eccentricity ratio of the damper under each bearing load according to the journal eccentricity and the oil film thickness of the damper under the bearing load; According to the directional displacement and coordinates corresponding to the grid nodes on the inner oil film surface of the elastic ring three-dimensional model and the directional displacement and coordinates corresponding to the grid nodes on the oil film surface of the inner sleeve three-dimensional model, the relative distance between the inner oil film surface of the elastic ring and the oil film surface of the inner sleeve of the damper under each eccentricity ratio is obtained, and the relative distance between the inner oil film surface of the elastic ring and the oil film surface of the inner sleeve is used as the inner oil film gap; According to the directional displacements and coordinates corresponding to the grid nodes on the outer oil film surface of the elastic ring three-dimensional model and the directional displacements and coordinates corresponding to the grid nodes on the oil film surface of the outer bushing three-dimensional model, the relative distance between the outer oil film surface of the elastic ring three-dimensional model and the oil film surface of the outer bushing three-dimensional model of the damper under each eccentricity ratio is obtained, and the relative distance between the outer oil film surface of the elastic ring three-dimensional model and the oil film surface of the outer bushing three-dimensional model is used as the outer oil film gap; Among them, the oil film gap of the damper is divided into the outer oil film gap and the inner oil film gap.

4. The method for optimizing the boss structure of an elastic ring type squeeze film damper according to claim 1, characterized in that: Taking the oil film gap as the input parameter and obtaining the oil film dynamic characteristics based on the generalized Reynolds equation, the steps of solving the oil film pressure field using the finite difference method are as follows: Based on the generalized Reynolds equation, the control equations corresponding to the inner ring oil film pressure field and the outer ring oil film pressure field of the damper elastic ring are derived; Based on the control equation, the oil film gap, journal eccentricity and node pressure values are non-dimensionalized to obtain the non-dimensionalized pressure field control equation of the elastic ring. The finite difference method is used to solve the dimensionless pressure field control equation of the elastic ring to obtain the oil film pressure field.

5. The method for optimizing the boss structure of an elastic ring type squeeze film damper according to claim 1, characterized in that: The preset optimization parameter ranges include: The optimized parameter range of the boss width is set according to the arc length of the substructure sandwiched between the center lines of adjacent inner bosses; The optimized parameter range of the boss height is set according to the average radius of the elastic ring.

6. The method for optimizing the boss structure of an elastic ring type squeeze film damper according to claim 1, characterized in that: When selecting the optimization parameters, the sum of the height of the outer boss and the height of the inner boss remains unchanged.

7. The method for optimizing the boss structure of an elastic ring type squeeze film damper according to claim 1, characterized in that: The expression of the constraint function is: Where, Indicates the The constraint function values corresponding to the group optimization parameters; represents the elastic ring stiffness before optimizing the boss structure; Indicates in Elastic ring stiffness after optimizing boss structure under the set optimization parameters; Represents evolutionary algebra.

8. The method for optimizing the boss structure of an elastic ring type squeeze film damper according to claim 1, characterized in that: The expression of the objective function is: Where, Indicates the The objective function value corresponding to the group optimization parameters; Indicates the The circumferential relative oil film force of the damper corresponding to the boss structure with the optimized parameters; Indicates the The boss structure with the optimized parameters corresponds to the radial relative oil film force of the damper.

9. The method for optimizing the boss structure of an elastic ring type squeeze film damper according to claim 1, characterized in that: The particle swarm optimization algorithm is used to obtain the best optimization parameters among all groups of optimization parameters.

10. The method for optimizing the boss structure of an elastic ring type squeeze film damper according to claim 1, characterized in that: The steps of obtaining the best optimization parameters among all groups of optimization parameters based on the constraint function and the objective function and using the optimization algorithm are as follows: The corresponding set of optimization parameters when the constraint function is satisfied and the objective function value is maximized is taken as the best optimization parameters.

Images