Dynamic modeling method for squeeze film damper-gear rotor transmission system

Abstract

The invention relates to a dynamic modeling method for a squeeze film damper-gear rotor transmission system, which comprises the following steps of: establishing a multi-body dynamic model of a spiral bevel gear rotor transmission system by utilizing ADAMS software, establishing a mathematical model of the squeeze film damper by utilizing Visual Studio software, and establishing a multi-body dynamic model of the squeeze film damper-gear rotor transmission system by utilizing Visual Studio software. According to the method, the oil film force, the oil film rigidity, the oil film damping and other oil film dynamic characteristics are calculated, data exchange is conducted on the node displacement speed of the ADAMS model and the oil film dynamic characteristics of the VS mathematical model through the fluid-solid coupling principle, joint simulation of rapid solving is achieved, and the problem that the oil film effect cannot be considered in existing multi-body rotor dynamic model simulation is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation transmission, and relates to a dynamic modeling method of a squeeze film damper-gear rotor transmission system, and in particular to a dynamic modeling method of a squeeze film damper-gear rotor transmission system based on ADAMS and VS joint simulation. Background Art

[0002] Squeeze film damper is one of the important and effective methods to reduce the amplitude of the rotor when it passes through resonance and support the external transmission force. The squeeze film damper can reduce rotor vibration, suppress dynamic instability and has a certain ability to withstand sudden unbalanced loads. As a key component of the aviation transmission system, the spiral bevel gear has the advantages of large overlap, strong load-bearing capacity, high transmission ratio, smooth transmission and low noise. The high-pressure compressor rotor system is one of the key components of the aircraft gas turbine. The quality of its structural design directly determines the working efficiency and reliability of the compressor. The high-pressure compressor rotor system is subjected to the combined effects of complex loads such as aerodynamics, temperature, and mechanics during operation. Therefore, it has strict design requirements in terms of overall structure and rotor dynamics characteristics.

[0003] At present, the gear-rotor system dynamics model is mainly based on the gear-rotor coupling model. Commonly used modeling methods include concentrated mass method, finite element method, multi-body dynamics method, modal synthesis method, dynamic stiffness synthesis method and statistical energy method. Modeling through the above methods usually requires complex professional knowledge and sufficient programming and computing capabilities. The modeling is complex and takes a lot of time. For rotor modeling, Jeffcott rotors, beam units, etc. are usually used for simplification, which cannot fully consider the complex structure of the rotor. For finite element models, the complex structural characteristics of the rotor can be considered during modeling, but the calculation efficiency is low. After the squeeze film damper is introduced, the fluid-solid coupling analysis becomes more difficult. Summary of the invention

[0004] In view of this, in order to solve the technical problem that the dynamic characteristics of the oil film cannot be considered when modeling in order to analyze the dynamic characteristics of the gear rotor system with a squeeze film damper, the present invention provides a squeeze film damper-gear rotor transmission system dynamic modeling method based on ADAMS and VS (Visual Studio) joint simulation, which fully considers the oil film effect of the squeeze film damper and the structural characteristics of the rotor to solve the problem of efficient modeling and solution of the squeeze film damper-gear rotor system.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for dynamic modeling of a squeeze film damper-gear rotor transmission system comprises the following steps:

[0007] S1. Divide the SFD-gear rotor transmission system into an ADAMS gear rotor system multi-body dynamics model and a Visual Studio SFD mathematical model;

[0008] S2. Use ADAMS to establish a multi-body dynamics model of the gear rotor system, including the gear, bearing, shaft, and blade rotor subsystems;

[0009] S3. Write the oil film force subroutine based on Visual Studio and establish the mathematical model of squeeze film damper considering the boundary conditions of the damper;

[0010] S4. Using the node displacement velocity of the multi-body dynamics model of the gear rotor system established in step S2 as the input parameter of the mathematical model of the squeeze film damper in step S3, the oil film force is calculated by the mathematical model of the squeeze film damper, and then the oil film force calculated in step S3 is used as the input of the multi-body dynamics model of the gear rotor system in step S2, and a joint simulation is performed to obtain the dynamics model of the squeeze film damper-gear rotor transmission system.

[0011] Further, step S2 is specifically as follows:

[0012] S21. Use the gear system module of the ADAMS Machinery module to establish a gear model and determine the gear pair parameters, including the number of teeth, module, pressure angle, helix angle, hand direction, tooth width and other parameters. When the gears are meshing, there are normal contact force and tangential contact force at the meshing point. The impact function method is used to calculate the normal contact force of the gear meshing, and the Coulomb friction method is used to calculate the tangential contact force.

[0013] S22. Use the sleeve force module to build a bearing model. Select the corresponding bearing in MASTA according to the inner and outer diameters of the bearing, the bearing width and the number of rollers. Extract the bearing stiffness and use the sleeve force to simulate the bearing. The sleeve force in ADAMS is a flexible force. A sleeve is equivalent to integrating the stiffness and damping characteristics in the directions of three degrees of freedom of movement and three degrees of freedom of rotation.

[0014] S23. Establish a gear shaft model through the ADAMS entity module, and divide the gear shaft into multiple shaft segments according to the cross-sectional size, shaft segment length, material, and spatial position of the gear shaft;

[0015] S24. Create a three-dimensional model of the bladed rotor in SolidWorks, output it in a recognizable format and import it into ADAMS to obtain a rotor model.

[0016] Furthermore, in step S21, the impact function model equates the meshing contact process of the gear teeth to a nonlinear spring-damping model based on the penetration depth, and the normal contact force obtained thereby is composed of two parts: the elastic force generated by the mutual cutting of the gear teeth and the damping force generated by the relative velocity between the gear teeth; the elastic force component is equivalent to a nonlinear spring, and the direction of the damping force component is opposite to the direction of movement. A step function is used to define the damping, thereby avoiding sudden changes in the damping.

[0017] Further, in step S24, a three-dimensional model of the bladed rotor is established in SolidWorks according to the two-dimensional drawing, the material properties of the bladed rotor are defined, and the bladed rotor is output in a .x_t format recognizable by ADAMS, and the bladed rotor structure model in the .x_t format is imported into ADAMS.

[0018] Further, step S3 is specifically as follows:

[0019] S31. Establish the fluid control equation of the squeeze film damper

[0020] The flow conservation equation is derived according to the law of conservation of mass:

[0021]

[0022] Where x, y and z represent the tangential, radial and axial coordinates respectively; p is the oil film pressure; ρ is the fluid density; u, v and w are the velocity components of the oil film surface along the x, y and z directions respectively;

[0023] Assuming that the oil film is an isovistoric incompressible fluid and the fluid viscosity and density are constant, the governing equation applicable to the squeeze film damper is simplified to:

[0024]

[0025] u h , v h and w h are the velocity components of the upper surface of the oil film along the x, y and z directions, respectively; u0, v0 and w0 are the velocity components of the lower surface of the oil film along the x, y and z directions, respectively; h is the thickness of the oil film, and μ is the viscosity of the fluid;

[0026] Since the journal can only move along the X and Y axes, the velocity components of the oil film along the X and Y axes are also and Therefore, the velocity components of the oil film along the tangential, radial and axial directions are as follows:

[0027]

[0028] Where Ω is the precession angular velocity;

[0029] The fluid control equation of the squeeze film damper is obtained as follows:

[0030]

[0031] S32, solve the oil film pressure and oil film dynamic characteristics

[0032] The displacement velocity of the journal node solved by the ADAMS model is used as the external input of the fluid control equation to solve the transient oil film pressure. The control equation is discretized using the central finite difference method. R is the damper radius, c is the oil film gap, L is the damper width, and the dimensionless parameters Z = z / L, X = x / c, Y = y / c, H = h / c, P = p / p0, p0 = 2μR / c are introduced. The fluid control equation is rewritten as:

[0033] D i.j (P i.j ) l -A i.j (P i+1，j ) l -B i.j (P i-1，j ) l -C i.j (P i，j+1 ) l -C i.j (P i，j-1 ) l =-(F i.j ) l (5) D i.j =A i.j +B i.j +2C i.j ,

[0034] After solving the oil film pressure control equation to obtain the oil film pressure, use Simpson's law:

[0035]

[0036] The radial and circumferential components of the oil film are obtained:

[0037]

[0038] Then the oil film force along the X-axis and Y-axis is:

[0039] F ox =-F or cosβ+F ot sinβ (9)

[0040] F oy =-F or sinβ+F ot cosβ (10)

[0041] The oil film stiffness coefficient and oil film damping coefficient are:

[0042]

[0043] Where e is the eccentricity, from which the dynamic characteristics such as oil film force, oil film stiffness, and oil film damping are obtained.

[0044] Further, step S4 is specifically as follows: the solver obtains the displacement and velocity of the center of the rotating shaft as the input of the user subroutine, and the subroutine adopts the finite difference method to iteratively solve the oil film force, and is assisted by the corresponding convergence judgment algorithm to obtain the oil film force of the squeeze film damper at that moment, and the oil film force is used as the external force input of the multi-body dynamics model to solve the next analysis step, and this repetition can realize the fluid-solid coupling multi-body dynamics simulation based on ADAMS.

[0045] The beneficial effects of the present invention are:

[0046] 1. The dynamic modeling method of the squeeze film damper-gear rotor transmission system disclosed in the present invention adopts a method of combining user subroutines in order to consider the effect of the squeeze film damper in ADAMS. The oil film force subroutine is written based on Visual Studio, and the oil film thickness and oil viscosity of the squeeze film damper can be considered, thereby realizing fluid-solid coupling multi-body dynamic simulation based on ADAMS and Visual Studio.

[0047] 2. The method for dynamic modeling of a squeeze film damper-gear rotor transmission system disclosed in the present invention, when modeling a blade disk rotor, is modeled by SolidWorks and imported into ADAMS, fully considering the complex structural characteristics and natural frequency of the blade disk rotor; the complex dynamic model of the squeeze film damper-gear rotor system can be established relatively easily, which greatly simplifies the modeling process and effectively shortens the solution time.

[0048] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0050] Figure 1 It is a schematic diagram of the principle of the dynamic modeling method of the squeeze film damper-gear rotor transmission system of the present invention;

[0051] Figure 2 It is a schematic diagram of fluid lubrication in the dynamics modeling method of the squeeze film damper-gear rotor transmission system of the present invention;

[0052] Figure 3 It is a schematic diagram of the dynamic model of the squeeze film damper-gear rotor transmission system of the present invention;

[0053] Figure 4 This is an analysis diagram of the centroid speed and oil film force of the driving wheel of the squeeze film damper-gear rotor transmission system of the present invention. DETAILED DESCRIPTION

[0054] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0055] like Figure 1 A method for dynamic modeling of a squeeze film damper-gear rotor transmission system is shown, comprising the following steps:

[0056] S1. Divide the SFD-gear rotor transmission system into an ADAMS gear rotor system multi-body dynamics model and a Visual Studio SFD mathematical model;

[0057] S2. Use ADAMS to establish a multi-body dynamics model of the gear rotor system, including the gear, bearing, shaft, and blade rotor subsystems;

[0058] S21. Use the gear system module of the ADAMS Machinery module to establish a gear model and determine the gear pair parameters, including the number of teeth, module, pressure angle, helix angle, rotation direction, tooth width and other parameters. When the gears are meshing, there are normal contact force and tangential contact force at the meshing point. The impact function method is used to calculate the normal contact force of the gear meshing, and the Coulomb friction method is used to calculate the tangential contact force. The impact function model equates the meshing contact process of the gear teeth to a nonlinear spring-damper model based on the penetration depth. The normal contact force obtained is composed of two parts: the elastic force generated by the mutual cutting of the gear teeth and the damping force generated by the relative velocity between the gear teeth. The elastic force component is equivalent to a nonlinear spring, and the direction of the damping force component is opposite to the direction of movement. The step function is used to define the damping to avoid sudden changes in damping;

[0059] S22. Use the sleeve force module to build a bearing model. Select the corresponding bearing in MASTA according to the inner and outer diameters of the bearing, the bearing width and the number of rollers. Extract the bearing stiffness and use the sleeve force to simulate the bearing. The sleeve force in ADAMS is a flexible force. A sleeve is equivalent to integrating the stiffness and damping characteristics in the directions of three degrees of freedom of movement and three degrees of freedom of rotation.

[0060] S23. Establish a gear shaft model through the ADAMS entity module, and divide the gear shaft into multiple shaft segments according to the cross-sectional size, shaft segment length, material, and spatial position of the gear shaft;

[0061] S24. Establish a three-dimensional model of the bladed rotor in SolidWorks, output it in a recognizable format and import it into ADAMS to obtain a rotor model. Establish a three-dimensional model of the bladed rotor in SolidWorks according to the two-dimensional drawing, define the material properties of the bladed rotor, output it in a .x_t format recognizable by ADAMS, and import the bladed rotor structure model in the .x_t format into ADAMS;

[0062] S3. Write the oil film force subroutine based on Visual Studio and establish the mathematical model of squeeze film damper considering the boundary conditions of the damper;

[0063] S31. Establish the fluid control equation of the squeeze film damper

[0064] The flow conservation equation is derived according to the law of conservation of mass:

[0065]

[0066] Where x, y and z represent the tangential, radial and axial coordinates respectively; p is the oil film pressure; ρ is the fluid density; u, v and w are the velocity components of the oil film surface along the x, y and z directions respectively.

[0067] like Figure 2 Assume that the oil film is an isovistoric incompressible fluid and the fluid viscosity and density are constant, which simplifies to the governing equations for the squeeze film damper:

[0068]

[0069] u h , v h and w h are the velocity components of the upper surface of the oil film along the x, y and z directions respectively, u0, v0 and w0 are the velocity components of the lower surface of the oil film along the x, y and z directions respectively, h is the oil film thickness, and μ is the fluid viscosity.

[0070] Since the journal can only move along the X and Y axes, the velocity components of the oil film along the X and Y axes are also and Therefore, the velocity components of the oil film along the tangential, radial and axial directions are as follows:

[0071]

[0072] Where Ω is the precession angular velocity.

[0073] The fluid control equation of the squeeze film damper is obtained as follows:

[0074]

[0075] S32, solve the oil film pressure and oil film dynamic characteristics

[0076] The displacement velocity of the journal node solved by the ADAMS model is used as the external input of the fluid control equation to solve the transient oil film pressure. The control equation is discretized using the central finite difference method. R is the damper radius, c is the oil film gap, L is the damper width, and the dimensionless parameters Z = z / L, X = x / c, Y = y / c, H = h / c, P = p / p0, p0 = 2μR / c are introduced. The fluid control equation is rewritten as:

[0077] D i.j (P i.j ) l -A i.j (P i+1,j ) l -B i.j (P i-1,j ) l -C i.j (P i,j+1 ) l -C i.j (P i,j-1 ) l =-(F i.j ) l (5)

[0078] In the formula

[0079] D i.j =A i.j +B i.j +2C i.j ,

[0080]

[0081] After solving the oil film pressure control equation to obtain the oil film pressure, use Simpson's law:

[0082]

[0083] The radial and circumferential components of the oil film are obtained:

[0084]

[0085] Then the oil film force along the X-axis and Y-axis is:

[0086] F ox =-F or cosβ+F ot sinβ (9)

[0087] F oy =-F or sinβ+F ot cosβ (10)

[0088] The oil film stiffness coefficient and oil film damping coefficient are:

[0089]

[0090] Where e is the eccentricity, from which the dynamic characteristics such as oil film force, oil film stiffness, and oil film damping are obtained;

[0091] S4, using the node displacement velocity of the multi-body dynamics model of the gear rotor system established in step S2 as the input parameter of the mathematical model of the squeeze film damper in step S3, calculating the oil film force through the mathematical model of the squeeze film damper, and then using the oil film force calculated in step S3 as the input of the multi-body dynamics model of the gear rotor system in step S2, and performing joint simulation to obtain the following: Figure 3 The dynamic model of the squeeze film damper-gear rotor transmission system is shown.

[0092] Specifically: In order to consider the effect of the squeeze film damper in ADAMS, it is necessary to combine the user subroutine. The oil film force subroutine is written based on Visual Studio, and the oil film thickness and oil viscosity of the squeeze film damper can be considered.

[0093] The solver obtains the displacement and velocity of the center of the rotating shaft as the input of the user subroutine. The subroutine uses the finite difference method to iteratively solve the oil film force, and with the assistance of the corresponding convergence judgment algorithm, the oil film force of the squeeze film damper at that moment can be obtained. The oil film force is used as the external force input of the multi-body dynamics model to solve the next analysis step. This repetition can realize the fluid-solid coupling multi-body dynamics simulation based on ADAMS.

[0094] Figure 4 This is the analysis diagram of the center of mass velocity and oil film force of the driving wheel of the squeeze film damper-gear rotor transmission system. It can be seen that the oil film force of the squeeze film damper on the supporting object is caused by the "squeeze effect", and the phase difference between the oil film force and the speed of the journal is always 180°.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for dynamic modeling of a squeeze film damper-gear rotor transmission system, characterized in that: The following steps are involved: S1. Divide the SFD-gear rotor transmission system into an ADAMS gear rotor system multi-body dynamics model and a Visual Studio SFD mathematical model; S2. Use ADAMS to establish a multi-body dynamics model of the gear rotor system, including the gear, bearing, shaft, and blade rotor subsystems; S3. Write the oil film force subroutine based on Visual Studio and establish the mathematical model of squeeze film damper considering the boundary conditions of the damper; S4. Using the node displacement velocity of the multi-body dynamics model of the gear rotor system established in step S2 as the input parameter of the mathematical model of the squeeze film damper in step S3, calculating the oil film force through the mathematical model of the squeeze film damper in step S3, and then using the oil film force calculated in step S3 as the input of the multi-body dynamics model of the gear rotor system in step S2, and performing joint simulation to obtain the dynamics model of the squeeze film damper-gear rotor transmission system.

2. The method for dynamic modeling of a squeeze film damper-gear rotor transmission system according to claim 1, characterized in that: Step S2 is specifically as follows: S21. Use the gear system module of the ADAMS Machinery module to establish a gear model and determine the gear pair parameters, including the number of teeth, module, pressure angle, helix angle, hand direction, and tooth width parameters. When the gears are meshing, there are normal contact force and tangential contact force at the meshing point. The impact function method is used to calculate the normal contact force of the gear meshing, and the Coulomb friction method is used to calculate the tangential contact force. S22. Use the sleeve force module to build a bearing model. Select the corresponding bearing in MASTA according to the inner and outer diameters of the bearing, the bearing width and the number of rollers. Extract the bearing stiffness and use the sleeve force to simulate the bearing. The sleeve force in ADAMS is a flexible force. A sleeve is equivalent to integrating the stiffness and damping characteristics in the directions of three degrees of freedom of movement and three degrees of freedom of rotation. S23. Establish a gear shaft model through the ADAMS entity module, and divide the gear shaft into multiple shaft segments according to the cross-sectional size, shaft segment length, material, and spatial position of the gear shaft; S24. Create a three-dimensional model of the bladed rotor in SolidWorks, output it in a recognizable format and import it into ADAMS to obtain a rotor model.

3. The method for dynamic modeling of a squeeze film damper-gear rotor transmission system according to claim 2, characterized in that: In step S21, the impact function model equates the meshing contact process of the gear teeth to a nonlinear spring-damping model based on the penetration depth. The normal contact force obtained is composed of two parts: the elastic force generated by the mutual penetration of the gear teeth and the damping force generated by the relative velocity between the gear teeth. The elastic force component is equivalent to a nonlinear spring, and the direction of the damping force component is opposite to the direction of movement. A step function is used to define the damping to avoid sudden changes in the damping.

4. The method for dynamic modeling of a squeeze film damper-gear rotor transmission system according to claim 2, characterized in that: In step S24, a three-dimensional model of the bladed rotor is established in SolidWorks according to the two-dimensional drawing, the material properties of the bladed rotor are defined, and the model is output in a .x_t format recognizable by ADAMS, and the bladed rotor structure model in the .x_t format is imported into ADAMS.

5. The method for dynamic modeling of a squeeze film damper-gear rotor transmission system according to claim 2, characterized in that: Step S3 is specifically as follows: S31. Establish the fluid control equation of the squeeze film damper The flow conservation equation is derived according to the law of conservation of mass: Where x, y and z represent the tangential, radial and axial coordinates respectively; p is the oil film pressure; ρ is the fluid density; u, v and w are the velocity components of the oil film surface along the x, y and z directions respectively; Assuming that the oil film is an isovistoric incompressible fluid and the fluid viscosity and density are constant, the governing equation applicable to the squeeze film damper is simplified to: u h , v h and w h are the velocity components of the upper surface of the oil film along the x, y and z directions, respectively; u0, v0 and w0 are the velocity components of the lower surface of the oil film along the x, y and z directions, respectively; h is the thickness of the oil film, and μ is the viscosity of the fluid; Since the journal can only move along the X and Y axes, the velocity components of the oil film along the X and Y axes are also and Therefore, the velocity components of the oil film along the tangential, radial and axial directions are as follows: Where Ω is the precession angular velocity; The fluid control equation of the squeeze film damper is obtained as follows: S32, solve the oil film pressure and oil film dynamic characteristics The displacement velocity of the journal node solved by the ADAMS model is used as the external input of the fluid control equation to solve the transient oil film pressure. The control equation is discretized using the central finite difference method. R is the damper radius, c is the oil film gap, L is the damper width, and the dimensionless parameters Z = z / L, X = x / c, Y = y / c, H = h / c, P = p / p0, p0 = 2μR / c are introduced. The fluid control equation is rewritten as: D i.j (P i.j ) l -A i.j (P i+1,j ) l -B i.j (P i-1,j ) l -C i.j (P i,j+1 ) l -C i.j (P i,j-1 ) l =-(F i.j ) l (5) Where: D i.j =A i.j +B i.j +2C i.j , After solving the oil film pressure control equation to obtain the oil film pressure, use Simpson's law: The radial and circumferential components of the oil film are obtained: Then the oil film force along the X-axis and Y-axis is: F ox =-F or cosβ+F ot sinβ (9) F oy =-F or sinβ+F ot cosβ (10) The oil film stiffness coefficient and oil film damping coefficient are: Where e is the eccentricity, from which the dynamic characteristics such as oil film force, oil film stiffness and oil film damping are obtained.

6. The method for dynamic modeling of a squeeze film damper-gear rotor transmission system according to claim 1, characterized in that: Step S4 is specifically as follows: the solver obtains the displacement and velocity of the center of the rotating shaft as the input of the user subroutine. The subroutine uses the finite difference method to iteratively solve the oil film force, and uses the corresponding convergence judgment algorithm to obtain the oil film force of the squeeze film damper at that moment. The oil film force is used as the external force input of the multi-body dynamics model to solve the next analysis step. This process is repeated to realize the fluid-solid coupling multi-body dynamics simulation based on ADAMS.

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