A method and device for determining an aero-engine casing vibration measuring point

Abstract

The application provides an aero-engine casing vibration measuring point determination method and device, and relates to the technical field of engine testing. The method comprises the following steps: a one-dimensional dynamic model of a rotor-support system and a three-dimensional finite element model of a casing system are established; under a preset operating condition, external loads transmitted to the casing through the support are calculated according to the one-dimensional dynamic model, and are applied to the three-dimensional finite element model to obtain vibration responses of each node of the casing; the nodes of the casing are screened according to the vibration responses to determine candidate measuring points, and response sensitivity is calculated based on vibration response changes of the candidate measuring points under rotor excitation changes; and a vibration measuring point layout scheme of the casing surface is determined according to the response sensitivity. By establishing a coupling analysis model of the rotor system and the casing system, and combining vibration responses and response sensitivity to screen and optimize the layout of the measuring points, the sensitivity of the vibration measuring points to the rotor excitation changes is improved, so that the effectiveness and reliability of engine vibration monitoring are improved.

Description

Technical Field

[0001] This application relates to the field of engine testing technology, and in particular to a method and apparatus for determining vibration measurement points of an aero-engine casing. Background Technology

[0002] In the development and testing of rotating machinery such as aero-engines and gas turbines, the overall vibration characteristics are crucial indicators for evaluating the system's operational safety and stability. To obtain information on the overall operating status, vibration sensors are typically placed on the casing surface to monitor and analyze the casing's vibration response. Therefore, determining the appropriate locations of vibration measurement points on the casing surface is a key issue in the design of overall vibration testing. On the one hand, in existing technologies, the placement of casing vibration measurement points usually relies primarily on engineering experience or is aided by a small amount of simulation analysis. This approach lacks a systematic theoretical basis and can easily lead to unreasonable measurement point placement, thus affecting the accuracy of vibration test results. On the other hand, if a three-dimensional finite element model of the entire machine is directly used for response calculation in simulation analysis, the large number of degrees of freedom in the model results in low computational efficiency. Furthermore, it is difficult to accurately model the dynamic transmission characteristics of complex support structures such as bearings, extrusion oil film dampers, and squirrel cage supports, leading to significant deviations between the simulated casing vibration response distribution and actual operating conditions. Therefore, how to improve the accuracy of casing vibration response prediction while ensuring computational efficiency, and thereby achieve reasonable determination of casing vibration measurement points, has become a pressing technical problem in this field. Summary of the Invention

[0003] In view of this, this application provides a method and apparatus for determining vibration measurement points of an aero-engine casing, in order to solve the problems of low efficiency in whole-engine simulation calculation and insufficient accuracy in predicting casing vibration response in the prior art.

[0004] Specifically, this application is implemented through the following technical solution:

[0005] The first aspect of this application provides a method for determining vibration measurement points of an aero-engine casing, the method comprising:

[0006] A one-dimensional dynamic model of the rotor-support system is established based on the rotor structural parameters and the support structural parameters, and a three-dimensional finite element model of the casing system is established based on the casing structural parameters.

[0007] Under preset operating conditions, based on the one-dimensional dynamic model of the rotor-support system, the external load transmitted from the support to the casing system is calculated, and the external load is applied to the connection position corresponding to the support in the three-dimensional finite element model of the casing system to calculate the vibration response of each node of the casing.

[0008] The casing nodes are screened based on the vibration response of each node to determine candidate measurement points;

[0009] The response sensitivity of each candidate measuring point is calculated based on the vibration response change of the candidate measuring points under the condition of rotor excitation variation;

[0010] The layout scheme of vibration measuring points on the casing surface is determined based on the response sensitivity.

[0011] A second aspect of this application provides a device for determining vibration measurement points of an aero-engine casing, the device comprising a modeling module, a calculation module, and a determination module, wherein:

[0012] The modeling module is used to establish a one-dimensional dynamic model of the rotor-support system based on the rotor structural parameters and support structural parameters, and to establish a three-dimensional finite element model of the casing system based on the casing structural parameters.

[0013] The calculation module is used to calculate the external load transmitted from the support to the casing system under preset operating conditions, based on the one-dimensional dynamic model of the rotor-support system, and to apply the external load to the connection position corresponding to the support in the three-dimensional finite element model of the casing system, so as to calculate the vibration response of each node of the casing.

[0014] The calculation module is used to screen the casing nodes based on the vibration response of each node of the casing in order to determine candidate measurement points;

[0015] The calculation module is used to calculate the response sensitivity of each candidate measurement point based on the vibration response change of the candidate measurement point under the condition of rotor excitation change;

[0016] The determining module is used to determine the layout scheme of vibration measuring points on the surface of the casing based on the response sensitivity.

[0017] The method and apparatus for determining vibration measurement points of aero-engine casing provided in this application construct a joint simulation analysis framework that combines a one-dimensional dynamic model of the rotor-support system with a three-dimensional finite element model of the casing system. Based on the one-dimensional dynamic model, an external load is established. Through the three-dimensional finite element model and the external load's characteristic vibration response transmission model, efficient prediction of casing vibration response is achieved. Physical modeling of the rotor excitation transmission path improves the accuracy and engineering applicability of vibration response analysis. Specifically, this application first establishes a one-dimensional dynamic model of the rotor-support system based on rotor and support structural parameters, and then establishes a three-dimensional finite element model of the casing system based on casing structural parameters. This allows the complex dynamic behavior of the rotor system to be efficiently solved using a low-degree-of-freedom one-dimensional model, while simultaneously maintaining the ability to express the spatial vibration response distribution of the casing structure using the three-dimensional finite element model. This ensures computational efficiency while improving the accuracy of casing vibration response prediction. Based on this, the external load transmitted from the support to the casing system is calculated using the one-dimensional dynamic model of the rotor-support system. This external load characterizes the combined effects of rotor unbalance excitation, bearing nonlinear force, and oil film force. The external load is then applied to the connection positions corresponding to the support in the three-dimensional finite element model of the casing system to obtain the vibration response of each node in the casing. This effectively transmits the rotor vibration excitation to the casing structure's vibration response, improving the physical consistency of the response calculation. Furthermore, the casing nodes are screened based on their vibration responses to determine candidate measurement points. The response sensitivity of each candidate measurement point is calculated based on the changes in vibration response under varying rotor excitation conditions. Based on this response sensitivity, the layout of vibration measurement points on the casing surface is determined. In summary, this application improves the accuracy of casing vibration response prediction through joint simulation analysis using a one-dimensional dynamic model and a three-dimensional finite element model, combined with a support-based load transfer mechanism. Simultaneously, by optimizing and screening measurement points based on vibration response characteristics and their sensitivity to excitation changes, the layout of casing vibration measurement points can be determined more rationally, improving the reliability of vibration test design. Attached Figure Description

[0018] Figure 1 A flowchart of Embodiment 1 of the method for determining vibration measurement points of an aero-engine casing provided in this application;

[0019] Figure 2 This is a schematic diagram of the structure of Embodiment 1 of the aircraft engine casing vibration measurement point determination device provided in this application. Detailed Implementation

[0020] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0021] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used herein are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0022] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0023] The following specific embodiments are given to illustrate the technical solution of this application in detail.

[0024] Figure 1 This is a flowchart of an embodiment of the method for determining vibration measurement points of an aero-engine casing provided in this application. Please refer to... Figure 1 The method provided in this embodiment may include:

[0025] S101. Establish a one-dimensional dynamic model of the rotor-support system based on the rotor structural parameters and support structural parameters, and establish a three-dimensional finite element model of the casing system based on the casing structural parameters.

[0026] Specifically, the rotor shaft system is discretized and modeled based on the rotor structural parameters to establish a rotor model describing the rotor's dynamic characteristics. Simultaneously, a support model describing the support's dynamic characteristics is established based on the support structural parameters, and a one-dimensional dynamic model of the rotor-support system is formed based on the structural connection relationship between the rotor model and the support model. Furthermore, the casing structure is discretized using three-dimensional finite element methods based on the casing structural parameters to establish a three-dimensional finite element model of the casing system. By constructing the one-dimensional dynamic model of the rotor-support system and the three-dimensional finite element model of the casing system, a foundational model is provided for subsequent calculations of the external loads transmitted from the rotor vibration excitation to the casing structure through the support, as well as the vibration response of each node in the casing.

[0027] Optionally, in one possible implementation, establishing a one-dimensional dynamic model of the rotor-support system based on rotor structural parameters and support structural parameters includes:

[0028] (1) Establish a rotor model to describe the rotor dynamic characteristics based on the rotor structure parameters.

[0029] Specifically, the rotor model is used to characterize the mass distribution and structural connection relationships of the rotor system during rotation, thereby providing a basis for the subsequent calculation of rotor dynamic response.

[0030] Optionally, in one possible implementation, establishing the rotor model based on the rotor structure parameters includes:

[0031] (A) Determine multiple characteristic positions in the direction of the rotor axis based on the rotor structure parameters, and set discrete nodes at the characteristic positions.

[0032] Specifically, the rotor structural parameters may include the geometric dimensions, material parameters, and structural connection relationships of each structural component of the rotor shaft system. Geometric dimensions may include the axial length, inner diameter, outer diameter, and cross-sectional change positions of each shaft segment and disk; material parameters may include material density, elastic modulus, shear modulus, and Poisson's ratio; structural connection relationships may include the connection sequence between each shaft segment and disk, and the installation position of each structural component along the rotor axis. In practical engineering applications, the above rotor structural parameters can be obtained in various ways. For example, relevant geometric dimensions can be obtained from the structural design drawings of the entire aero-engine or rotor components; the dimensions and installation positions of each structural component of the rotor can also be extracted using computer-aided design models; furthermore, material parameters and structural connection relationships can be obtained from design databases or experimental measurement data.

[0033] Furthermore, after obtaining the aforementioned rotor structure parameters, the rotor structure can be discretized along the rotor axis to determine several characteristic locations. These characteristic locations typically include the end positions of each shaft segment, the disk mounting position, locations where the structural cross-sectional dimensions change, and the mounting positions of the support structures. Discrete nodes are set at these characteristic locations, thus forming a set of discrete nodes distributed along the rotor axis. These discrete nodes represent the dynamic state variables of the rotor structure at the corresponding positions, such as displacement, velocity, and acceleration, providing a discretization basis for subsequent rotor model building.

[0034] (B) Establish a rotor mass unit at each of the discrete nodes to characterize the concentrated mass and moment of inertia of the rotor at that discrete node.

[0035] Specifically, the rotor mainly consists of a shaft segment structure and a disk structure. Considering the variable cross-section characteristics of the rotor shaft system along the axial direction, the rotor structure can be characterized by a combination of constant cross-section beam elements, tapered cross-section beam elements, and irregular variable cross-section beam elements. Specifically, based on the changes in the cross-sectional dimensions of each shaft segment and disk in the rotor structure parameters, the rotor structure can be divided into multiple beam elements along the axial direction.

[0036] Specifically, for beam elements with irregularly varying cross-sectional dimensions, based on the principle of constant mass and moment of inertia of the center of mass, the irregularly variable cross-section beam element can be equivalent to a beam element with a constant cross-section. After the equivalence treatment, each beam element has definite calculation parameters, including material density, axial length, inner diameter, outer diameter, elastic modulus, shear modulus, and Poisson's ratio. The geometric parameters can be obtained from rotor structure design drawings or CAD models, and the material parameters can be obtained from material databases or material handbooks. Based on these parameters, a finite element dynamic model of the beam element can be established using Timoshenko Beam theory. Compared with the Euler beam model, the Timoshenko Beam model considers both bending and shear deformation simultaneously, making it more suitable for the dynamic analysis of high-speed rotating machinery rotor systems.

[0037] (C) Establish connection units based on the structural connection relationship between adjacent discrete nodes, and use the connection units to dynamically connect the rotor mass units at adjacent discrete nodes to form the rotor model.

[0038] Specifically, based on the finite element method, discrete nodes are connected for each beam element. Then, according to the topological relationships between the discrete nodes, the mass matrix, gyro matrix, and stiffness matrix of each beam element are assembled. These matrices can be derived from Timoshenko beam theory and expressed based on the degrees of freedom of the element nodes. This yields the dynamic equations of the entire rotor system:

[0039] ;

[0040] in, This is the generalized displacement vector of the rotor, used to represent the displacement degrees of freedom of each discrete node; The first derivative of the generalized displacement vector of the rotor with respect to time is used to represent the velocity of each discrete node; Let be the second derivative of the generalized displacement vector of the rotor with respect to time, used to represent the acceleration of each discrete node; wherein, the above-mentioned dotted variables all represent the derivative of the corresponding physical quantity with respect to time. This is the rotor mass matrix, used to reflect the mass distribution characteristics of the rotor system; This is the rotor gyroscope matrix, used to describe the gyroscopic effect generated by the rotor's rotational motion; This is the rotor stiffness matrix, used to reflect the overall stiffness characteristics of the rotor structure; This is the rotor damping matrix, used to describe the structural damping effect. In some implementations, it can be represented using the Rayleigh damping model. This is the generalized excitation force vector of the rotor, which can include the unbalanced excitation force of the rotor and the reaction force of the support structure acting on the rotor system. By assembling the matrices of each beam element, a complete rotor model can be obtained, thus forming a rotor model for describing the rotor's dynamic characteristics and providing a foundation for subsequent calculations of the dynamic response of the rotor-support system.

[0041] (2) Establish a support model to describe the dynamic characteristics of the support based on the support structure parameters.

[0042] Specifically, the support model is used to characterize the dynamic characteristics of the support structure in the rotor system, thereby reflecting the influence of the support on the vibration response of the rotor system.

[0043] Optionally, in one possible implementation, establishing the support model based on the support structure parameters includes:

[0044] (A) Determine the installation position of each support in the direction of the rotor axis according to the support structure parameters, and match the installation position with the discrete node to determine the discrete node corresponding to the support.

[0045] Specifically, the support structure parameters may include bearing type, bearing installation position, elastic support structure parameters, squeeze film damper structure parameters, and support mass parameters. The bearing installation position is typically determined by aero-engine structural design drawings or a 3D CAD model, and is represented as an axial coordinate position along the rotor axis. After obtaining the support installation position, it is matched with discrete nodes arranged along the axial direction in the rotor model. When the axial installation position of a support coincides with or is within a preset tolerance range of a discrete node, that discrete node is designated as the connection node for that support. This determines the positions of the discrete nodes corresponding to each support in the rotor model and establishes the connection relationship between the rotor system and the support system, providing a foundation for the subsequent establishment of the support dynamics model. In actual engineering implementation, the support installation position can be obtained from aero-engine structural design drawings or a 3D CAD assembly model.

[0046] (B) Determine the equivalent stiffness parameter, equivalent damping parameter and mass parameter of the support based on the aforementioned support structure parameters.

[0047] Specifically, the support system typically includes components such as rolling bearings, elastic support structures, and squeeze film dampers. The rolling bearings bear the rotor load and provide radial support, the elastic support connects the bearings to the casing structure and provides elastic support, and the squeeze film dampers provide additional damping to reduce system vibration. In some embodiments, the equivalent stiffness characteristics provided by the bearings to the rotor system can be determined based on the structural parameters, contact characteristics, and material parameters of the rolling bearings; the equivalent damping characteristics of the system can be determined based on the geometric dimensions, lubricant properties, and working clearance of the squeeze film dampers; and the mass distribution of the support components can be determined based on the geometric dimensions and material density of the support structure, thereby obtaining the equivalent mass parameters of the support system. These structural parameters can be obtained through structural design drawings or 3D CAD models, thus enabling the determination of the equivalent parameters of the support system.

[0048] Specifically, in some embodiments, the support system may also include an elastic support structure, such as a squirrel-cage elastic support. The equivalent stiffness of the squirrel-cage elastic support structure can be expressed as:

[0049] ;

[0050] in, The equivalent stiffness of the squirrel cage elastic support structure. The number of bars in the rat cage. The elastic modulus of the material. The height of the cage bar cross section is _____. This refers to the length of the long side of the rat cage bars. The length of the short side of the cage bars. The length of the cage bars is given. In some embodiments, the equivalent damping parameter can be characterized by the oil film damping force generated by the squeeze oil film damper.

[0051] (C) Based on the equivalent stiffness parameter, equivalent damping parameter and mass parameter, establish the support dynamic equation at the discrete node to form the support model.

[0052] Specifically, the support node is considered as a dynamic node with mass, stiffness, and external damping, and corresponding dynamic equilibrium equations are established at the node. In some implementations, the support node is... direction and The dynamic equation in the direction can be expressed as:

[0053] ;

[0054] in, To support the equivalent mass, To support the equivalent stiffness, and The support nodes are respectively direction and Displacement in the direction, and For the corresponding connection node of the casing direction and Displacement in the direction, and The force is the external force acting on the support nodes. By establishing the above dynamic equations at all support nodes and combining them with the rotor system dynamic model, a support model describing the dynamic characteristics of the support can be formed. Its matrix form can be expressed as:

[0055] ;

[0056] in, This is a vector composed of the displacements of all support nodes. For the support mass matrix, Here is the support stiffness matrix. This is the generalized external force vector acting on each support node.

[0057] Optionally, in one possible implementation, the support dynamics equation includes at least an external force term, which includes rolling bearing force and squeeze oil film damping force, wherein (a) the rolling bearing force is calculated based on the relative displacement between the rotor and the support.

[0058] Specifically, the relative displacement is decomposed in the radial plane into components along... direction and The displacement components in the circumferential direction are determined, and based on the spatial distribution of each rolling element in the circumferential direction, the displacement components are projected onto the contact normal direction corresponding to each rolling element, wherein the contact normal direction of each rolling element is determined by its angular position on the circumference. The local contact deformation between each rolling element and the raceway is determined; further, the contact state between the rolling element and the raceway is determined based on the local contact deformation, and the contact force generated by each rolling element is calculated based on the contact deformation. Finally, the contact forces of each rolling element in its corresponding direction are decomposed and superimposed to obtain the supporting force of the rolling bearing in each coordinate direction.

[0059] Specifically, in rolling bearings, the contact force between the rolling elements and the inner and outer raceways can be described using Hertzian contact theory. When relative displacement occurs between the rotor and the support, elastic contact deformation occurs between each rolling element and the raceway, resulting in a nonlinear contact force. Rolling bearings in... direction and The forces acting in the direction can be expressed as follows:

[0060] ;

[0061] ;

[0062] in, and These represent rolling bearings in direction and The supporting force generated in the direction; The number of rolling elements; The Hertzian contact stiffness coefficient is determined by the bearing material and the geometric parameters of the rolling elements and raceways, and is used to reflect the contact elastic characteristics between the rolling elements and raceways. and The relative displacement between the rotor and the support, where , , and For rotor nodes at direction and Displacement in the direction, and This represents the displacement of the supporting node in the corresponding direction; This refers to the radial clearance of the bearing. For the first The instantaneous angular position of each rolling element; The Heaviside step function takes the value 1 if the value within the parentheses is greater than zero, and 0 otherwise. It represents the contact condition between the rolling element and the raceway, meaning that contact force is only generated when the rolling element is compressed. By introducing the Heaviside function, a piecewise description of the rolling element contact state is achieved, thus ensuring that contact force is generated only under contact compression conditions. The angular position of the rolling element... It can be represented as:

[0063] ;

[0064] in, To maintain the rack speed, For time, This refers to the rolling element number. In some embodiments, the cage rotational speed can be further expressed as:

[0065] ;

[0066] in, The rotor speed is The inner raceway radius of the bearing is... Let be the radius of the outer raceway of the bearing. Through the above calculations, the nonlinear support forces of the rolling bearing in two orthogonal directions can be obtained.

[0067] (b) Calculate the damping force of the squeeze oil film based on the relative displacement and velocity between the support and the casing.

[0068] Specifically, a squeeze film damper (SFD) can be installed in the support structure to provide additional damping between the support and the casing, thereby reducing rotor system vibration. Based on short bearing theory and combined with semi-Sommerfeld boundary conditions, the squeeze film damper... direction and The oil film forces in the direction can be expressed as follows:

[0069] ;

[0070] ;

[0071] in, and These respectively represent the compression oil film damper in direction and The oil film force generated by the direction; The dynamic viscosity of the lubricating oil; The radius of the squeeze oil film damper; The length of the squeeze oil film damper; This refers to the radial clearance of the oil film. and The dimensionless displacement ratios are respectively and ,in , , and For the displacement of the support node, and This represents the displacement of the corresponding node in the casing; The journal eccentricity is expressed as follows: ; Let be the journal precession angle, and its expression is: In some implementations, a two-parameter arctangent function can be used for calculation; Let be the precession angular velocity, and its expression is: ; The rate of change of eccentricity, i.e. The derivative with respect to time; , and The Sommerfeld integral coefficients are functions of the eccentricity and can be obtained through numerical integration or table lookup. Through the above calculations, the film damping force of the extrusion film damper in two orthogonal directions can be obtained.

[0072] (c) The rolling bearing force and the extrusion oil film damping force are used as external force terms in the dynamic equation of the support.

[0073] Specifically, at the support node, the rolling bearing force from the rotor acts as the excitation force, while the oil film force generated by the squeeze oil film damper acts as the damping force between the support and the casing. After obtaining the rolling bearing force and the squeeze oil film damping force, they can be used as external force terms in the support dynamics equation. These external force terms... and It can be represented as:

[0074] ;

[0075] ;

[0076] in, and For rolling bearings direction and The supporting force generated in the direction, and These are the oil film forces generated by the extrusion oil film damper in the corresponding directions. Since the extrusion oil film damping force is a damping force opposite to the direction of relative motion of the support node, in the established coordinate system, its direction of action on the support node is opposite to the direction of action of the rolling bearing force in the corresponding direction. Therefore, a negative sign is used in the external force term to indicate its effect. In this way, the rolling bearing force and the extrusion oil film damping force can be introduced into the support dynamics equation, thereby determining the external force term of the support node.

[0077] (3) Based on the structural connection relationship between the rotor model and the support model, the rotor model and the support model are combined to form a one-dimensional dynamic model of the rotor-support system.

[0078] Specifically, the structural connection relationships are determined by the connection relationships between the rotor discrete nodes and the support nodes. The support nodes are connected to the corresponding discrete nodes of the rotor via rolling bearings and to the casing structure via elastic supports and compression oil film dampers. Through these connection relationships, the dynamic equations of the rotor system and the support system can be uniformly assembled, thereby establishing a complete rotor-support system dynamic model. In one possible implementation, the dynamic equations of the rotor system can be coupled with the dynamic equations at each support node, and the system matrix can be assembled according to the connection relationships between the nodes to obtain the overall dynamic equations of the rotor-support system, which can be expressed as:

[0079] ;

[0080] in, It is the generalized displacement vector of the rotor-support system, which is composed of the displacement degrees of freedom of each discrete node of the rotor and the support node. The system mass matrix is ​​obtained by assembling the rotor mass matrix and the equivalent mass parameters of the supports. The system damping matrix describes the damping effect in the system. In some implementations, this damping effect can be composed of structural damping and oil film damping generated by the squeeze oil film damper. Here is the system gyroscope matrix. This is the system stiffness matrix, which is formed by the rotor structure stiffness and the equivalent stiffness of the support structure. This is the generalized external force vector of the system, which can include external excitations such as rotor unbalance excitation force, rolling bearing contact force, and extrusion oil film damping force. In some embodiments, since the rolling bearing contact force and the oil film force generated by the extrusion oil film damper are typically nonlinear functions of displacement and velocity, the aforementioned external force vector... This can be expressed as a nonlinear function of the system state variables, making the rotor-support system dynamic equations nonlinear dynamic equations. By combining the rotor model and the support model using the above dynamics, a complete one-dimensional dynamic model of the rotor-support system can be formed. Based on this model, the dynamic response of the rotor system under different speed conditions can be further analyzed, such as calculating the rotor vibration response, critical speed, and stability characteristics.

[0081] Specifically, after establishing a one-dimensional dynamic model of the rotor-support system, a three-dimensional finite element model of the casing system can be established based on the casing structural parameters. In some embodiments, a three-dimensional geometric model of the casing structure can first be established based on the structural design parameters of the aero-engine casing. Then, the casing structure is discretized using finite element methods, dividing it into multiple finite element elements to form a three-dimensional finite element model of the casing system. The casing structural parameters may include the geometric dimensions of the casing shell, material density, elastic modulus, Poisson's ratio, and the connection position between the casing and the support structure. These parameters can be obtained from casing structural design drawings, three-dimensional models, or material parameter tables.

[0082] Specifically, after finite element discretization, the mass matrix and stiffness matrix of the casing system can be assembled based on the mass and stiffness properties of each finite element. In some implementations, these matrices can be automatically generated by finite element analysis software, for example, by modeling the casing structure and assembling the element matrices using finite element software. Furthermore, a casing damping matrix can be established based on the damping characteristics of the casing structure, for example, by determining the damping parameters of the casing structure using the Rayleigh damping model or a material damping model.

[0083] Furthermore, to describe the connection relationship between the casing structure, the support structure, and the engine mounting structure, the casing structure stiffness matrix, the support structure stiffness matrix, and the mounting structure stiffness matrix can be introduced into the casing finite element model. The casing structure stiffness matrix describes the elastic stiffness characteristics of the casing structure itself; the support structure stiffness matrix describes the elastic connection relationship between the casing and the support structure formed by the squirrel-cage elastic support structure; and the mounting structure stiffness matrix describes the constraint relationship between the engine casing and the external mounting structure through the mounting joint. Based on the above, the dynamic equation of the casing system can be obtained, and its expression is:

[0084] ;

[0085] in, Let be the generalized displacement vector of the finite element model of the casing. For the casing mass matrix, For the casing damping matrix, Here is the stiffness matrix of the casing structure. The support structure stiffness matrix is ​​used to simulate the elastic connection between the casing structure and the rotor support through the squirrel-cage elastic support structure. It can be obtained by assembling the equivalent stiffness parameters in the aforementioned support model. To install the structural stiffness matrix, The generalized external force vector acting on the casing system can include the casing structure's own weight and external loads transmitted to the casing structure through the support structure. In this way, a three-dimensional finite element model describing the dynamic characteristics of the casing structure can be established, thus providing a basis for analyzing the vibration response of each node of the casing.

[0086] S102. Under preset operating conditions, based on the one-dimensional dynamic model of the rotor-support system, calculate the external load transmitted to the casing system through the support, and apply the external load to the connection position corresponding to the support in the three-dimensional finite element model of the casing system to calculate the vibration response of each node of the casing.

[0087] Specifically, under preset operating conditions, the dynamic response of the rotor-support system can first be solved based on the one-dimensional dynamic model of the rotor-support system, and the external load transmitted to the casing structure at each support position can be calculated according to the connection relationship between the support nodes and the casing structure. Subsequently, the external load is applied to the connection nodes corresponding to the support structure in the three-dimensional finite element model of the casing system, and the vibration response of the casing structure under the action of the external load is solved by the finite element dynamic analysis method, thereby obtaining the vibration response results of each node of the casing.

[0088] Optionally, in one possible implementation, calculating the external load transmitted to the casing system through the support based on the one-dimensional dynamic model of the rotor-support system includes:

[0089] (1) Apply rotor excitation load to the one-dimensional dynamic model of the rotor-support system and solve the dynamic response at each support position.

[0090] Specifically, under preset operating conditions, a rotor excitation load is applied to the one-dimensional dynamic model of the rotor-support system, and the dynamic response of the rotor-support system is solved. The rotor excitation load can represent parameters characterizing the excitation intensity or characteristics of the rotor system, such as the magnitude of rotor unbalance, the amplitude of unbalance force, the amplitude of excitation force, or other parameters characterizing the degree of rotor excitation. The dynamic response can include the displacement response, velocity response, and acceleration response of each node in the system. In some embodiments, the Newmark-β numerical integration method can be used to solve the one-dimensional dynamic model of the rotor-support system using time-stepping to obtain the dynamic response results of the system at each time step. Specifically, before performing numerical integration calculations, the integration constant in the Newmark-β method can be determined first, and its expression is:

[0091] ;

[0092] ;

[0093] in, Indicates the time step. and The integration parameters for the Newmark-β method can be taken as follows in some implementations: , This corresponds to the constant average acceleration integral method, which exhibits good numerical stability. The aforementioned constants... ~ These are intermediate parameters used in the integration process to construct the effective stiffness matrix and the equivalent load expression. After obtaining the above integration constants, the effective stiffness matrix of the rotor-support system can be constructed, and its expression is:

[0094] ;

[0095] in, For the effective stiffness matrix, The mass matrix of the rotor-support system. Here is the damping matrix of the rotor-support system. Here is the stiffness matrix of the rotor-support system. and The above is the integration constant. The system's effective load at the next time step can then be calculated, expressed as:

[0096] ;

[0097] in, , and Let these represent the system's displacement vector, velocity vector, and acceleration vector at the current moment, respectively. This represents the external force vector for the next time step, which may include external excitations such as rotor unbalance excitation and bearing forces. After obtaining the effective stiffness matrix and effective load, the dynamic response for the next time step can be obtained by solving the following equation:

[0098] ;

[0099] in, , and These represent the displacement, velocity, and acceleration at the next time step, respectively. Through the above time-step calculation, the displacement and velocity responses of each support node in the rotor-support system at each time step can be obtained, that is, the dynamic response results at each support position can be obtained.

[0100] (2) Calculate the force exerted by the support on the casing structure based on the dynamic response to obtain the external load.

[0101] Specifically, after obtaining the dynamic response of the support node, the force exerted by the support on the casing structure can be further calculated based on the dynamic characteristics of the support structure, thereby obtaining the external load transmitted from the support to the casing structure. In some embodiments, the external load transmitted from the support to the casing can be calculated using the following relationship:

[0102] ;

[0103] ;

[0104] in, and They respectively represent the supports at direction and External loads transmitted to the casing structure in the direction To support the equivalent stiffness, For the support equivalent damping, and These respectively represent the support nodes at direction and Displacement response in the direction, and These respectively represent the support nodes at direction and Velocity response in direction, and This represents the squeezing oil film force generated at the support. Through the above calculations, the dynamic response of the rotor-support system can be converted into a dynamic external load acting on the casing structure. Compared to using a single-direction load or simplifying the load equivalently, this embodiment constructs external loads in multiple orthogonal directions. This not only reflects the distribution characteristics of the support load in different directions but also characterizes the coupled vibration relationship between each direction, thus more accurately describing the actual stress state transmitted from the rotor vibration to the casing structure through the support, improving the accuracy of casing vibration response prediction. In this way, the dynamic response result of the one-dimensional rotor-support system can be converted into the excitation load of the three-dimensional finite element model of the casing structure, thereby establishing the load transfer relationship between the dynamic behavior of the rotor system and the vibration response of the casing structure. Subsequently, the external load can be applied to the connection nodes corresponding to the support structure in the three-dimensional finite element model of the casing for subsequent calculation of the casing structure's vibration response under this operating condition.

[0105] Specifically, it will support external loads. and The load is applied to the corresponding support connection nodes in the three-dimensional finite element model of the casing system, forming the external load vector of the casing system. Compared to methods that use unidirectional loads or simplify and directly apply loads to a 3D model, this implementation constructs time-varying external loads based on the dynamic response of the rotor-support system. This allows the external loads to dynamically change with the system's operating state, thereby improving the precision and physical consistency of the casing structure's dynamic response calculation. In some implementations, numerical integration methods can be used to solve the casing system's dynamic equations in time steps, such as the Newmark-β method or other structural dynamics integration methods, to obtain the casing system's dynamic response at each time step. The relevant implementation principles and methods are described in the relevant documentation and will not be repeated here. After obtaining the vibration response of each node in the casing structure, the vibration displacement, vibration velocity, or vibration acceleration of each node in each direction can be further extracted as basic data for subsequent screening of candidate vibration measurement points.

[0106] As an optional embodiment, the method further includes, before applying the external load vector to the three-dimensional finite element model of the casing system:

[0107] The internal force components at the support interface are calculated based on the one-dimensional dynamic model of the rotor-support system, and the distributed load acting on the casing connection surface is constructed based on the interface stress state characterized by the internal force components.

[0108] Specifically, in the one-dimensional dynamic model of the rotor-support system, the internal force components of each support connection section, including axial force, can be extracted. Shear force in two orthogonal directions and Bending moments about two orthogonal directions and and torque This is used to characterize the overall stress state at the support interface. In this embodiment, the aforementioned cross-sectional internal force components can be calculated by the one-dimensional dynamic model at the support connection section based on the nodal forces and their positions, corresponding to the equivalent cross-sectional resultant force and resultant moment; in some embodiments, the aforementioned cross-sectional internal force components can also be obtained based on a three-dimensional beam element model. In the transverse vibration modeling scenario, the cross-sectional internal force components can degenerate into force and moment components in the radial plane.

[0109] Furthermore, based on the internal force components of the cross section, a distributed load can be constructed on the corresponding support connection surface in the three-dimensional finite element model of the casing system, and applied to the corresponding connection surface of the three-dimensional finite element model. Among these, the axial force... Used to create a uniformly distributed load along the axial direction, bending moment and Used to create a surface pressure distribution that varies linearly along different directions, shear force and Used to form in-plane shear load distribution, torque This is used to form a circumferential shear load distribution, thereby reconstructing the continuous force distribution at the support interface. In some embodiments, the axial force, shear force, bending moment, and torque can be converted into equivalent surface load distributions on corresponding nodes or elements and applied to the support connection surface of the three-dimensional finite element model of the casing system to realize the loading of the distributed load in the three-dimensional model. Based on the theory of elasticity, the stress distribution on any cross section can be uniquely determined by the axial force, shear force, bending moment, and torque. Therefore, the distributed load constructed by the force components within the cross section can equivalently reflect the actual stress state at the interface. Compared with the method of applying concentrated forces only at the nodes, this embodiment can extend the discrete node forces into continuous surface distributed loads, which not only improves the spatial resolution of the load transfer process but also avoids local stress distortion caused by concentrated loads, thereby improving the accuracy and physical consistency of the casing vibration response calculation.

[0110] S103. Screen the casing nodes according to the vibration response of each node to determine candidate measurement points.

[0111] Specifically, the casing nodes are preferably casing surface nodes. The casing nodes are screened based on their vibration response amplitudes under preset operating conditions to determine nodes with significant vibration characteristics as candidate measurement points. The vibration response amplitude can be the vibration displacement amplitude, vibration velocity amplitude, or vibration acceleration amplitude. Through this method, nodes with high vibration response characteristics can be selected from a large number of nodes in the casing finite element model, thereby narrowing the analysis scope for subsequent measurement point optimization and providing a basic node set for calculating the response sensitivity of candidate measurement points.

[0112] Optionally, in one possible implementation, the step of screening the casing nodes based on the vibration response of each node to determine candidate measurement points includes:

[0113] The casing nodes are screened based on the vibration response amplitude of each node, and the casing nodes with vibration response amplitude greater than a preset response threshold are selected as candidate measurement points.

[0114] Specifically, after obtaining the vibration response of each node in the casing, the vibration response amplitude of each node under a preset operating condition can be calculated first. In some embodiments, the vibration displacement, vibration velocity, or vibration acceleration response of the casing nodes at each time step can be statistically processed, for example, calculating the maximum value, root mean square value, or peak amplitude of the vibration response of each node to characterize the vibration intensity of that node. Subsequently, the vibration response amplitude of each node can be compared with a preset response threshold. When the vibration response amplitude of a certain casing node is greater than the preset response threshold, the casing node can be identified as a candidate measurement point; when the vibration response amplitude is less than or equal to the preset response threshold, the node can be removed from the candidate measurement point set.

[0115] Specifically, the preset response threshold can be determined based on the statistical distribution of the casing vibration response. For example, in some embodiments, the response threshold can be determined based on the average value, standard deviation, or percentile value of the vibration response amplitude at each node of the casing; in other embodiments, the response threshold can also be preset based on engineering experience or test data.

[0116] Optionally, in some embodiments, selection can also be based on the ranking of vibration response amplitudes of the casing nodes. For example, the vibration response amplitudes of each node in the casing can be ranked, and the top N nodes with the highest vibration response amplitudes can be selected as candidate measurement points, where N is a preset number of nodes. In other embodiments, selection can also be based on the spatial distribution characteristics of the casing vibration response on the casing structure. For example, multiple regions can be divided on the surface of the casing structure, and nodes with larger vibration response amplitudes can be selected as candidate measurement points in each region to ensure that the candidate measurement points have a certain degree of spatial uniformity on the casing surface. In still other embodiments, selection can be based on a combination of multiple vibration characteristic parameters. For example, the node vibration displacement amplitude, vibration velocity amplitude, and vibration acceleration amplitude can be considered simultaneously, and the casing nodes can be selected based on a comprehensive evaluation index to determine the set of candidate measurement points. Through the above methods, nodes with significant and representative vibration response characteristics can be selected from a large number of nodes in the casing finite element model as candidate measurement points, thereby narrowing the node range for subsequent sensitivity analysis and improving the computational efficiency of the vibration measurement point optimization process.

[0117] Optionally, in one possible implementation, the step of screening the casing nodes based on the vibration response of each node to determine candidate measurement points includes:

[0118] Based on the vibration response of the casing nodes, and combined with the vibration propagation path and casing structural characteristics, the casing nodes are screened to determine candidate measurement points.

[0119] Specifically, in the three-dimensional finite element model of the casing system, the input node for vibration excitation can be determined based on the support position or the rotor excitation position, and the propagation path of vibration in the casing structure can be analyzed based on the input node. In some embodiments, the maximum propagation distance of vibration energy in the casing structure can be estimated based on the casing material parameters, damping characteristics, and structural geometric parameters, and the maximum propagation distance can be used as a spatial constraint range to limit the screening area of ​​candidate measurement points.

[0120] Furthermore, the casing structure can be partitioned within the spatial constraints. In some embodiments, partitioning can be based on the geometric features or connection relationships of the casing structure, for example, using structural connection points or areas of abrupt stiffness change as partition boundaries. In other embodiments, casing nodes can be partitioned according to the rate of change of vibration response in space; when the rate of change of response between adjacent nodes exceeds a preset threshold, they are divided into different regions. After partitioning, casing nodes within each partition can be screened. In some embodiments, structural connection nodes or key stress-bearing nodes within each partition can be assigned higher weighting factors, giving them higher priority in the candidate measurement point screening process, thereby improving the ability of the selected measurement points to characterize the vibration transmission path. Through the above methods, candidate measurement points can be screened based on considering the vibration propagation path and structural characteristics. This not only ensures the coverage of the main vibration propagation area by the measurement points but also improves the sensitivity of the measurement points to the vibration characteristics of key structural parts. Thus, while ensuring spatial coverage of the measurement points, it improves the ability of the measurement points to characterize the vibration characteristics of key structural areas, further enhancing the accuracy and engineering applicability of the vibration measurement point layout.

[0121] S104. Calculate the response sensitivity of each candidate measuring point based on the vibration response change of the candidate measuring points under the condition of rotor excitation change.

[0122] Specifically, by changing the rotor excitation load and recalculating the vibration response of the casing system, vibration response data of candidate measuring points under different operating conditions are obtained, and the response sensitivity of each candidate measuring point is calculated accordingly. The response sensitivity characterizes how sensitive the vibration response of a candidate measuring point is to changes in rotor excitation. A higher response sensitivity indicates that the node is more sensitive to changes in rotor excitation and is more suitable as a vibration measuring point. In some embodiments, the response sensitivity of candidate measuring points can be calculated separately under multiple preset operating conditions, and the comprehensive response sensitivity of each candidate measuring point can be obtained through a weighted average, thus providing a basis for subsequently determining the vibration measuring point layout scheme on the casing surface.

[0123] Optionally, in one possible implementation, calculating the response sensitivity of each candidate measuring point based on the vibration response change of the candidate measuring points under varying rotor excitation conditions includes:

[0124] (1) Calculate the vibration response of the casing system under multiple preset operating conditions, and obtain the vibration response data of the candidate measuring points under each operating condition.

[0125] Specifically, different operating conditions are constructed by changing the rotor excitation load. For example, the magnitude of rotor imbalance, excitation force amplitude, or other parameters characterizing rotor excitation intensity can be changed, and the vibration response of the casing system can be calculated separately under each operating condition. Through the above calculations, vibration response data of candidate measuring points under different rotor excitation conditions can be obtained. For example, for a certain candidate measuring point, the vibration displacement response, vibration velocity response, or vibration acceleration response amplitude of that node under each operating condition can be obtained.

[0126] (2) Calculate the response sensitivity of each candidate measuring point under each operating condition based on the vibration response data.

[0127] Specifically, after obtaining vibration response data of candidate measuring points under different operating conditions, the response sensitivity of the candidate measuring points is calculated based on the vibration response changes caused by variations in rotor excitation. The response sensitivity of a candidate measuring point under a specific operating condition can be calculated using the following formula:

[0128] ;

[0129] in, The rotor excitation load under a certain operating condition, such as rotor imbalance or excitation force amplitude; This refers to the minute change in the rotor excitation load; For the rotor excitation load is Vibration response at candidate measurement points; To increase rotor excitation load The corresponding vibration response; This represents the response sensitivity of the candidate measuring point under the specified operating conditions. Through the above calculations, the response sensitivity values ​​of each candidate measuring point under different operating conditions can be obtained. The response sensitivity reflects the degree to which the vibration response of the candidate measuring point changes with rotor excitation; the higher the response sensitivity, the more sensitive the node is to changes in rotor excitation.

[0130] (3) The response sensitivity of each operating condition is calculated by weighting according to the preset weights corresponding to each operating condition, so as to obtain the response sensitivity of each candidate measurement point.

[0131] Specifically, to comprehensively consider the impact of multiple operating conditions on the selection of measuring points, the response sensitivity under each operating condition can be weighted according to preset weights to obtain the response sensitivity of candidate measuring points. The response sensitivity of candidate measuring points can be calculated using the following formula:

[0132] ;

[0133] in, For candidate measurement points in the th Response sensitivity under various operating conditions; For the first The weights corresponding to each operating condition; The number of operating conditions; The response sensitivity of the candidate measurement points is defined. Optionally, the weights of each operating condition can be set based on the proportion of engine operating time under different operating conditions, the importance of the condition, or engineering experience. For example, the corresponding weights can be determined based on the proportion of engine operating time under cruise, takeoff, and idling conditions. Through the above weighted calculation, the comprehensive response sensitivity of each candidate measurement point can be obtained, thus providing a basis for subsequently determining the vibration measurement point layout scheme on the casing surface based on the response sensitivity.

[0134] S105. Determine the layout scheme of vibration measuring points on the surface of the casing based on the response sensitivity.

[0135] Specifically, after obtaining the response sensitivity of each candidate measurement point, the candidate measurement points can be further screened based on the response sensitivity to determine the set of measurement points used to arrange the vibration sensors. In some embodiments, the set of measurement points can also be adjusted in combination with the actual engineering installation conditions of the casing structure to determine the layout scheme of vibration measurement points on the casing surface.

[0136] Optionally, in one possible implementation, determining the vibration measurement point layout scheme on the casing surface based on the response sensitivity includes:

[0137] (1) The candidate measurement points are screened according to the response sensitivity of each candidate measurement point to determine the initial measurement point set.

[0138] Specifically, after obtaining the response sensitivity of each candidate measurement point, the candidate measurement points can be screened according to preset rules to determine the initial measurement point set. Optionally, the candidate measurement points can be sorted from highest to lowest response sensitivity, and the top N candidate measurement points in terms of response sensitivity can be selected as the initial measurement point set, where N is the preset number of measurement points. Candidate measurement points with higher response sensitivity usually have higher response sensitivity to changes in rotor excitation, and are therefore more suitable as vibration measurement points. Optionally, candidate measurement points can be screened according to a response sensitivity threshold, for example, selecting candidate measurement points with a response sensitivity greater than a preset sensitivity threshold as the initial measurement point set. Through the above screening process, a set of measurement points with high vibration response sensitivity under theoretical analysis conditions can be obtained.

[0139] (2) Based on the installation space conditions of the casing structure and the sensor installation requirements, the initial set of measuring points is modified by engineering to obtain the vibration measuring point layout scheme on the casing surface.

[0140] Specifically, after obtaining the initial set of measurement points, the initial set can be further modified by engineering considerations based on the actual installation conditions of the casing structure to determine the final layout scheme of vibration measurement points on the casing surface. In some embodiments, the engineering modification can comprehensively consider multiple engineering factors, such as sensor installation space limitations, casing high-temperature area limitations, installation structure interference, and cable layout space conditions. Specifically, sensor installation space limitations can be used to avoid placing sensors in space-constrained areas; casing high-temperature area limitations can be used to avoid engine high-temperature areas to ensure reliable sensor operation; installation structure interference can be used to avoid interference between sensors and casing mounting structures, accessories, or pipelines; and cable layout space conditions can be used to comprehensively consider the routing and layout space of sensor cables. During engineering modification, the positions of some measurement points in the initial set can be appropriately adjusted according to the above engineering conditions, or alternative measurement points can be selected in adjacent areas, so that the determined measurement points have both high vibration response sensitivity and meet the actual engineering installation requirements. Through the above engineering modification process, the final layout scheme of vibration measurement points on the casing surface is determined based on the theoretical optimization results.

[0141] The method for determining vibration measurement points of an aero-engine casing provided in this application achieves efficient prediction of casing vibration response and reasonable determination of vibration measurement points by constructing a joint simulation analysis framework that combines a one-dimensional dynamic model of the rotor-support system with a three-dimensional finite element model of the casing system. Specifically, this application first establishes a one-dimensional dynamic model of the rotor-support system based on rotor structural parameters and support structural parameters, and then establishes a three-dimensional finite element model of the casing system based on the casing structural parameters. This allows the complex dynamic behavior of the rotor system to be efficiently solved using a low-degree-of-freedom one-dimensional model, while the three-dimensional finite element model maintains the ability to express the spatial vibration response distribution of the casing structure, thereby improving the accuracy of casing vibration response prediction while ensuring computational efficiency. Based on this, the external load transmitted from the support to the casing system is calculated according to the one-dimensional dynamic model of the rotor-support system, and the external load is applied to the connection position corresponding to the support in the three-dimensional finite element model of the casing system to obtain the vibration response of each node of the casing, thus realizing the accurate transmission of rotor vibration excitation to the casing structural vibration response. Furthermore, based on the vibration response of each node in the casing, candidate measurement points are selected. The response sensitivity of each candidate measurement point is calculated based on the vibration response changes under varying rotor excitation conditions. Therefore, the layout of vibration measurement points on the casing surface is determined based on the response sensitivity. In summary, this application, through joint simulation analysis using a one-dimensional dynamic model and a three-dimensional finite element model, improves the accuracy of casing vibration response prediction while maintaining computational efficiency. Furthermore, by optimizing and selecting measurement points based on vibration response characteristics, a reasonable layout of casing vibration measurement points can be determined, thereby improving the reliability of vibration test design.

[0142] Corresponding to the aforementioned embodiment of the method for determining vibration measurement points of an aero-engine casing, this application also provides an embodiment of an aero-engine casing vibration measurement point determination device.

[0143] Figure 2 This is a schematic diagram of the structure of Embodiment 1 of the aircraft engine casing vibration measurement point determination device provided in this application. Please refer to... Figure 2 The apparatus provided in this embodiment includes a modeling module 201, a calculation module 202, and a determination module 203, wherein:

[0144] The modeling module 201 is used to establish a one-dimensional dynamic model of the rotor-support system based on the rotor structural parameters and the support structural parameters, and to establish a three-dimensional finite element model of the casing system based on the casing structural parameters.

[0145] The calculation module 202 is used to calculate the external load transmitted from the support to the casing system according to the one-dimensional dynamic model of the rotor-support system under preset operating conditions, and to apply the external load to the connection position corresponding to the support in the three-dimensional finite element model of the casing system to calculate the vibration response of each node of the casing.

[0146] The calculation module 202 is used to screen the casing nodes based on the vibration response of each node of the casing in order to determine candidate measurement points;

[0147] The calculation module 202 is used to calculate the response sensitivity of each candidate measurement point based on the vibration response change of the candidate measurement point under the condition of rotor excitation change;

[0148] The determining module 203 is used to determine the vibration measuring point layout scheme on the surface of the casing based on the response sensitivity.

[0149] The apparatus of this embodiment can be used to perform... Figure 1 The steps of the method embodiment shown are similar in principle and process, and will not be repeated here.

[0150] The specific implementation process of the functions and roles of each unit in the above device can be found in the implementation process of the corresponding steps in the above method, and will not be repeated here.

[0151] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this application according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0152] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for determining vibration measuring points of an aero-engine casing, characterized in that, The method includes: A one-dimensional dynamic model of the rotor-support system is established based on the rotor structural parameters and the support structural parameters, and a three-dimensional finite element model of the casing system is established based on the casing structural parameters. Under preset operating conditions, based on the one-dimensional dynamic model of the rotor-support system, the external load transmitted from the support to the casing system is calculated, and the external load is applied to the connection position corresponding to the support in the three-dimensional finite element model of the casing system to calculate the vibration response of each node of the casing. The casing nodes are screened based on the vibration response of each node to determine candidate measurement points; The response sensitivity of each candidate measuring point is calculated based on the vibration response change of the candidate measuring points under the condition of rotor excitation variation; The layout scheme of vibration measuring points on the casing surface is determined based on the response sensitivity.

2. The method according to claim 1, characterized in that, The establishment of a one-dimensional dynamic model of the rotor-support system based on rotor structural parameters and support structural parameters includes: A rotor model describing the rotor dynamics characteristics is established based on the rotor structure parameters. A support model describing the dynamic characteristics of the support is established based on the support structure parameters. Based on the structural connection relationship between the rotor model and the support model, the rotor model and the support model are combined to form a one-dimensional dynamic model of the rotor-support system.

3. The method according to claim 2, characterized in that, The step of establishing a rotor model based on the rotor structure parameters includes: Based on the rotor structure parameters, multiple characteristic positions are determined along the rotor axis, and discrete nodes are set at the characteristic positions. At each of the discrete nodes, a rotor mass element is established to characterize the concentrated mass and moment of inertia of the rotor at that discrete node. Based on the structural connection relationship between adjacent discrete nodes, connection units are established, and the rotor mass units at adjacent discrete nodes are dynamically connected using the connection units to form the rotor model.

4. The method according to claim 3, characterized in that, The step of establishing the support model based on the support structure parameters includes: The installation position of each support in the direction of the rotor axis is determined according to the support structure parameters, and the installation position is matched with the discrete node to determine the discrete node corresponding to the support. The equivalent stiffness parameter, equivalent damping parameter, and mass parameter of the support are determined based on the aforementioned support structure parameters. Based on the equivalent stiffness parameter, equivalent damping parameter, and mass parameter, the support dynamics equations are established at the discrete nodes to form the support model.

5. The method according to claim 4, characterized in that, The support dynamics equation includes at least an external force term, which includes rolling bearing force and extrusion oil film damping force, wherein the rolling bearing force is calculated based on the relative displacement between the rotor and the support. The damping force of the squeeze oil film is calculated based on the relative displacement and velocity between the support and the casing. The rolling bearing force and the extrusion oil film damping force are used as external force terms in the dynamic equation of the support.

6. The method according to claim 1, characterized in that, The step of screening the casing nodes based on the vibration response of each node to determine candidate test points includes: The casing nodes are screened based on the vibration response amplitude of each node, and the casing nodes with vibration response amplitude greater than a preset response threshold are selected as candidate measurement points.

7. The method according to claim 1, characterized in that, The calculation of the response sensitivity of each candidate measuring point based on the vibration response change of the candidate measuring points under rotor excitation variation includes: The vibration response of the casing system is calculated under multiple preset operating conditions, and the vibration response data of the candidate measuring points under each operating condition are obtained. The response sensitivity of each candidate measuring point under each operating condition is calculated based on the vibration response data. The response sensitivity of each operating condition is calculated by weighting the preset weights corresponding to each operating condition to obtain the response sensitivity of each candidate measurement point.

8. The method according to claim 1, characterized in that, The calculation of the external load transmitted to the casing system through the support, based on the one-dimensional dynamic model of the rotor-support system, includes: Apply rotor excitation load to the one-dimensional dynamic model of the rotor-support system and solve for the dynamic response at each support location; The force exerted by the support on the casing structure is calculated based on the dynamic response to obtain the external load.

9. The method according to claim 1, characterized in that, The step of determining the vibration measurement point layout scheme on the casing surface based on the response sensitivity includes: Candidate measurement points are screened based on the response sensitivity of each candidate measurement point to determine the initial set of measurement points; The initial set of measuring points is modified by engineering based on the installation space conditions of the casing structure and the sensor installation requirements to obtain a vibration measuring point layout scheme on the casing surface.

10. A device for determining vibration measuring points of an aero-engine casing, characterized in that, The device includes a modeling module, a calculation module, and a determination module, wherein: The modeling module is used to establish a one-dimensional dynamic model of the rotor-support system based on the rotor structural parameters and support structural parameters, and to establish a three-dimensional finite element model of the casing system based on the casing structural parameters. The calculation module is used to calculate the external load transmitted from the support to the casing system under preset operating conditions, based on the one-dimensional dynamic model of the rotor-support system, and to apply the external load to the connection position corresponding to the support in the three-dimensional finite element model of the casing system, so as to calculate the vibration response of each node of the casing. The calculation module is used to screen the casing nodes based on the vibration response of each node of the casing in order to determine candidate measurement points; The calculation module is used to calculate the response sensitivity of each candidate measurement point based on the vibration response change of the candidate measurement point under the condition of rotor excitation change; The determining module is used to determine the layout scheme of vibration measuring points on the surface of the casing based on the response sensitivity.

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