Digital twin modeling method and digital twin of aeroengine rotor system

Abstract

The present invention discloses a digital twin modeling method and a digital twin of an aero-engine rotor system, and relates to the technical field of an engine rotor system, including: establishing a digital twin of a rotor system by a finite element method; reducing the model of the digital twin by a model reduction method; the model reduction method is a fixed interface modal synthesis method, and the model reduction is achieved by obtaining the main mode of a finite element model of a fully constrained rotor system and intercepting a low-order mode; simulating and calculating the vibration signal of the digital twin; obtaining the position of real-time monitoring of a physical entity, comparing the simulated vibration signal of the position with the measured vibration signal, analyzing and calculating the error between the two, and correcting the load parameters and support parameters of the digital twin in real time based on the error, so that the simulated signal and the measured signal are highly consistent. The present invention reduces the model degree of freedom by a model reduction method, improves the efficiency of calculation and analysis, and ensures the real-time performance of interactive mapping.

Description

Technical Field

[0001] The present invention relates to the technical field of engine rotor systems, and in particular to a real-time interactive digital twin modeling method and a digital twin of an aero-engine rotor system. Background Art

[0002] The rotor system of an aero-engine has a complex structure, variable loads, harsh working conditions, and many nonlinear factors. Its vibration behavior is complex and causes rotor failures of varying degrees, but the full vibration behavior of the aero-engine rotor system is still unclear. Theoretical analysis is difficult to accurately reflect the vibration characteristics of the aero-engine rotor system. Numerical simulation can only achieve calculations under a single working condition, and it is impossible to monitor the vibration behavior of the rotor in real time, and the accuracy of the calculation is difficult to guarantee. Experimental research is limited by factors such as long cycles, high costs, and high risks. To address this problem, digital twins can reflect the vibration behavior of the physical entity of the aero-engine rotor system in real time, and can be used for real-time status monitoring and fault warning. In addition, the real-time data interaction between the digital twin and the physical entity can ensure the accuracy of the digital twin.

[0003] Digital twin technology requires that the digital twin reflect the behavior characteristics of the physical entity in real time to achieve real-time status monitoring and fault behavior warning. However, the aircraft engine rotor system has a complex structure and many degrees of freedom, which leads to high computational costs for digital twins and makes it difficult to ensure the real-time interactive mapping between the digital twin and the physical entity. If the real-time interaction between the digital twin and the physical entity cannot be guaranteed, the digital twin will not be able to receive the vibration signal of the physical entity in real time, which will seriously affect the modeling accuracy of the digital twin and will not be able to achieve real-time status monitoring. Therefore, the real-time interactive mapping modeling of digital twins has important scientific and practical significance.

[0004] The existing digital twin modeling methods for rotor systems have provided some modeling schemes. Although they can establish digital twins of rotor systems, they often require the introduction of huge amounts of computation, which significantly increases the computation time of the digital twins and seriously affects the real-time interaction between the digital twins and the physical entities. However, no specific scheme is given to ensure the real-time nature of the interaction, and the established twin models are relatively complex, making it difficult to achieve real-time interaction between the digital twins and the physical entities, which seriously affects the accuracy of the digital twins. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a digital twin modeling method and digital twin of an aircraft engine rotor system. In view of the problem that the aircraft engine rotor system has a complex structure and many degrees of freedom, a digital twin modeling method based on model reduction is provided. The model degrees of freedom are reduced by the model reduction method, the efficiency of calculation and analysis is improved, and the real-time nature of interactive mapping is ensured. A digital twin is established to ensure real-time interactive mapping of the vibration behavior of the rotor system, and real-time interactive mapping between the digital twin of the rotor system and the physical entity is realized, thereby improving the modeling accuracy of the digital twin and realizing real-time status monitoring.

[0006] To this end, the present invention provides the following technical solutions:

[0007] In one aspect, the present invention provides a digital twin modeling method for an aero-engine rotor system, the method comprising:

[0008] Obtain the geometrical dimension parameters, material parameters, load parameters and operating speed of the rotor system;

[0009] Establishing a digital twin of the rotor system by using a finite element method based on geometric dimension parameters, material parameters, load parameters and operating speed of the rotor system;

[0010] The fixed interface modal synthesis method is used to reduce the model of the digital twin; the fixed interface modal synthesis method achieves model reduction by obtaining the main mode of the finite element model of the fully constrained rotor system and intercepting the low-order mode;

[0011] The vibration signal of the digital twin after model reduction is simulated and calculated to obtain a simulated vibration signal.

[0012] Furthermore, it also includes:

[0013] Real-time monitoring of the vibration signal of the rotor system during physical entity operation to obtain a measured vibration signal, wherein the measured vibration signal includes vibration displacement, velocity and acceleration;

[0014] The real-time monitoring position of the physical entity is obtained, the simulated vibration signal at that position is compared with the measured vibration signal, the error between the two is analyzed and calculated, and the load parameters and support parameters of the digital twin are corrected in real time based on the error to make the simulated signal consistent with the measured signal.

[0015] Furthermore, the measured vibration signal is obtained by an eddy current displacement sensor and an acceleration sensor.

[0016] Furthermore, the geometrical dimension parameters, material parameters and load parameters of the rotor system are obtained, including:

[0017] Obtain geometric dimension parameters from the geometric drawings or 3D models of the rotor system;

[0018] Obtain material parameters from the grades of materials used for the rotating shaft and rotating disk;

[0019] The load parameters are obtained according to the influence coefficient method.

[0020] Furthermore, the digital twin model includes the nonlinear factors of rolling bearings, the nonlinear factors of combined supports and the time-varying stiffness characteristics of the connection structure.

[0021] Furthermore, the nonlinear factors of rolling bearings are obtained through Hertz contact theory and elastic mechanics derivation as well as finite element method.

[0022] Furthermore, the fixed interface modal synthesis method is used to reduce the model of the digital twin, including:

[0023] When the support is of normal stiffness, the stiffness K and mass M matrices are extracted; the constraint modal matrix is ​​calculated;

[0024] When the support is fully constrained, modal analysis is performed and the main modal matrix is ​​calculated;

[0025] Obtaining a coordinate transformation matrix based on the main modal matrix and the constraint modal matrix;

[0026] The coordinate transformation matrix is ​​used to obtain the vibration equation of the rotor system with reduced dimension.

[0027] On the other hand, the present invention also provides a real-time interactive digital twin of an aircraft engine rotor system constructed using the digital twin modeling method of the above-mentioned engine rotor system.

[0028] On the other hand, the present invention also provides a computer-readable storage medium, which stores a computer instruction set. When the computer instruction set is executed by a processor, it implements the digital twin modeling method of the aircraft engine rotor system as mentioned above.

[0029] Advantages and positive effects of the present invention:

[0030] 1. The present invention proposes a specific solution to ensure real-time interaction between digital twins and physical entities, namely, integrating the model reduction method with the digital twin modeling method, shortening the calculation time, and realizing real-time status monitoring.

[0031] 2. In the present invention, after the real-time interaction between the digital twin and the physical entity is realized, the frequency of data correction and update of the digital twin is greatly increased, which improves the accuracy of the digital twin and also improves the accuracy of real-time status monitoring.

[0032] 3. The measurement positions of the whole-machine vibration test of the aircraft engine rotor system are limited, the collected data is scarce, and the vibration signal collection positions of the physical entity are limited. In the present invention, the vibration signals of the digital twin and the physical entity are corrected at the corresponding positions. The vibration signals at other positions of the digital twin can restore the vibration signals of the difficult-to-measure positions of the physical entity to the greatest extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 It is a flow chart of a digital twin modeling method of an aircraft engine rotor system in an embodiment of the present invention;

[0035] Figure 2 A flowchart of model reduction modeling in an embodiment of the present invention;

[0036] Figure 3 A schematic diagram of a rotor system in an embodiment of the present invention;

[0037] Figure 4 1 is a time domain and frequency spectrum diagram of a finite element modal reduction model in an embodiment of the present invention;

[0038] Figure 5 The time domain and spectrum diagrams are obtained by using the unreduced finite element method to model the model in the embodiment of the present invention. DETAILED DESCRIPTION

[0039] The present invention provides a digital twin modeling method and a digital twin of an engine rotor system, and provides a specific method for ensuring real-time interaction between the digital twin and the physical entity, that is, combining the model reduction method with the digital twin modeling method, which can improve the calculation efficiency and shorten the calculation time.

[0040] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0041] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0042] like Figure 1 As shown, it shows a flow chart of a digital twin modeling method of an aircraft engine rotor system in an embodiment of the present invention, the method comprising:

[0043] S1. Obtaining geometrical dimension parameters, material parameters, load, and operating speed of the aero-engine rotor system;

[0044] In a specific implementation, the geometric dimension parameters are obtained from the geometric drawings or three-dimensional models of the rotor system, the material parameters are obtained from the grades of the materials used for the rotating shaft and the rotating disk, and the load parameters are obtained according to the influence coefficient method.

[0045] S2. Based on the obtained geometric size parameters, material parameters, loads, and operating speed of the aircraft engine rotor system, a digital twin of the rotor system is established by using the finite element method;

[0046] In a specific implementation, the rotor model is established using the finite element method. For example, the finite element model of the shaft and the disk is represented by PIPE16 shaft unit and MASS21 concentrated mass unit in ANSYS simulation, or the finite element model is directly established by MATLAB.

[0047] The nonlinear factors of rolling bearings are considered in the digital twin; the nonlinear factors of rolling bearings can be obtained through Hertz contact theory, elastic mechanics derivation and finite element method.

[0048] The nonlinear factors of the combined support and the time-varying stiffness characteristics of the connection structure are considered in the digital twin.

[0049] S3, using the model reduction method to reduce the model of the digital twin;

[0050] Due to the complex structure of the engine rotor system, when using the finite element method to discretize the model and solve the response, in order to ensure the calculation accuracy, it is often necessary to divide it into multiple units, which makes the dimension of the motion equation too large and the calculation time too long. In order to reduce the amount of calculation in magnitude, the fixed interface modal synthesis method is used in the embodiment of the present invention to reduce the overall structural freedom. The basic idea of ​​the fixed interface modal synthesis method is to divide the system into several substructures according to engineering viewpoints or geometric shapes, and assume that the interfaces of each substructure are all fixed constraints. The modes of each substructure after the constraints are calculated, and then they are assembled and transformed according to the idea of ​​the branch modal synthesis method to obtain the overall low-order mode. It is usually used in numerical simulation models and is an effective method for solving vibration problems of large and complex structures. The present invention creatively applies the fixed interface modal synthesis method to the research on digital twin reduction modeling. The specific steps are as follows: Figure 2 As shown, including:

[0051] S301. When the support is of normal stiffness, extract the stiffness (K) and mass (M) matrices; calculate the constrained modal matrix according to formula (3); when the support is fully constrained, perform modal analysis to obtain low-order modal vibration shapes (main modal matrix) and frequencies;

[0052] First, calculate the rotor system model in the fully constrained state, use the LANB method to perform modal analysis, intercept the low-order modes of the modal vibration shape, and then establish the rotor system model under linear stiffness support to extract the stiffness and mass matrix and save it as a txt file. Finally, in MATLAB, restore it to full matrix storage according to the Harwell-Boeing file, use the rotor system degree of freedom sequence number, divide the degrees of freedom of the rotor system finite element model according to the support interface degree of freedom and non-support interface degree of freedom (internal degree of freedom), and get the following matrix form:

[0053]

[0054] Where M, G, and K are mass, damping, and stiffness matrices, respectively; sets I and J represent non-interface degrees of freedom and interface degrees of freedom, respectively.

[0055] In the fixed interface modal synthesis method, the modal basis is in the form of [T] = [Φ k :Φ C ], is the mass-normalized constrained principal mode matrix, The constrained modal matrix Φ is obtained by obtaining the main modes of the finite element model of the fully constrained rotor system and intercepting the low-order modes. c Defined on the set J, assume that the coordinates in the set J are moved by unit displacement in turn, and force the remaining coordinates to be 0. The set of static deformations generated by the physical coordinate u is called the mode defined on the set J, which is determined by the following equation:

[0056]

[0057] The constraint modal expression is:

[0058] Φ c =Φ IJ =-(K II ) -1 K IJ (3)

[0059] S302, obtaining a conversion matrix T according to formula (4);

[0060] The transformation relationship between physical coordinates and modal coordinates is:

[0061]

[0062] In the formula, is the main mode coordinate; Im is the unit matrix; nk is the number of main modes with retained constraints; T is the coordinate transformation matrix

[0063] S303. According to formula (5), the dynamic equation is reduced using the transformation matrix T to obtain the vibration equation of the rotor system after the dimension is reduced.

[0064] Combining the above transformation matrix, the vibration equation of the rotor system with reduced dimension is obtained. The rotor system equation is reduced from 4n order to n J +n k Stage:

[0065]

[0066] In the formula,

[0067] S4. Real-time monitoring of vibration signals during the operation of the physical entity of the rotor system to obtain measured vibration signals, including vibration displacement, velocity and acceleration;

[0068] Among them, the vibration signal can be obtained through eddy current displacement sensor and acceleration sensor.

[0069] S5. Perform simulation calculation on the vibration signal of the digital twin to obtain a simulated vibration signal;

[0070] S6. Obtain the real-time monitoring position of the physical entity, compare the simulated vibration signal and the measured vibration signal at the position, analyze and calculate the error between the two, and make real-time corrections to the load parameters and support parameters of the digital twin based on the error, so that the simulated signal and the measured signal are highly consistent.

[0071] After correcting the digital twin, the accuracy of the digital twin is ensured, and then the load parameters and support parameters are obtained, and the vibration signals at other positions are calculated, which can be used to obtain the vibration signals of the difficult-to-measure positions of the aircraft engine rotor system.

[0072] Combined with the digital twin modeling method of model reduction, in order to verify the reduction of calculation time, the following example is used for verification. The rotor system used for verification is as follows: Figure 3 shown.

[0073] The rotor system is modeled using the finite element method and the finite element model reduction method, and the vibration signal calculation results of the reduced and unreduced models are given as follows: Figure 4 and Figure 5 As shown, it can be seen that the reduced vibration signal is basically consistent with the unreduced model, indicating that the reduction result is accurate and effective. More importantly, the reduced model takes 3 seconds to calculate, while the unreduced model takes 13 seconds to calculate, and the calculation efficiency is improved by 4.3 times. Therefore, the digital twin modeling method for ensuring real-time interactive mapping proposed in the present invention can greatly improve the calculation efficiency and shorten the calculation time while ensuring the accuracy of the calculation, and ensure the real-time interaction between the digital twin and the physical entity, thereby improving the twin correction frequency and modeling accuracy.

[0074] Compared with the existing digital twin modeling technology, the digital twin modeling method in the embodiment of the present invention can realize real-time interaction between the digital twin and the physical entity and realize real-time status monitoring. At the same time, the frequency of data correction and update of the digital twin is greatly increased, which improves the accuracy of the digital twin and further improves the accuracy of real-time status monitoring.

[0075] The vibration signal collection locations of the physical entity of the aircraft engine rotor system are limited. The vibration signals of the digital twin and the physical entity are corrected one-to-one according to the location, and the vibration signals of the digital twin are used to restore the vibration signals of the difficult-to-measure locations of the physical entity of the aircraft engine rotor system. This is of great significance to the vibration behavior analysis and fault diagnosis of the aircraft engine rotor system.

[0076] In another embodiment, the present invention also provides a real-time interactive digital twin of an aircraft engine rotor system constructed using the above-mentioned digital twin modeling method.

[0077] In another embodiment, the present invention further provides a computer-readable storage medium, which stores a computer instruction set. When the computer instruction set is executed by a processor, it implements a digital twin modeling method of an aircraft engine rotor system as provided in any of the above embodiments.

[0078] In the several embodiments provided by the present invention, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0079] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0080] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0081] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A digital twin modeling method for an aero-engine rotor system, characterized in that: The method comprises: Obtain the geometrical dimension parameters, material parameters, load parameters and operating speed of the rotor system; Establishing a digital twin of the rotor system by using a finite element method based on geometric dimension parameters, material parameters, load parameters and operating speed of the rotor system; The fixed interface modal synthesis method is used to reduce the model of the digital twin; the fixed interface modal synthesis method achieves model reduction by obtaining the main mode of the finite element model of the fully constrained rotor system and intercepting the low-order mode; the fixed interface modal synthesis method is used to reduce the model of the digital twin, including: when the support is normal stiffness, extracting the stiffness K and mass M matrices; calculating the constraint modal matrix; when the support is fully constrained, performing modal analysis and calculating the main modal matrix; obtaining the coordinate transformation matrix based on the main modal matrix and the constraint modal matrix; using the coordinate transformation matrix to obtain the vibration equation of the rotor system after the dimension is reduced; The vibration signal of the digital twin after model reduction is simulated and calculated to obtain a simulated vibration signal.

2. The digital twin modeling method of an aircraft engine rotor system according to claim 1, characterized in that: Also includes: Real-time monitoring of the vibration signal of the rotor system during physical entity operation to obtain a measured vibration signal, wherein the measured vibration signal includes vibration displacement, velocity and acceleration; Obtain the real-time monitoring position of the physical entity, compare the simulated vibration signal at that position with the measured vibration signal, analyze and calculate the error between the two, and make real-time corrections to the load parameters and support parameters of the digital twin based on the error to make the simulated signal consistent with the measured signal.

3. The digital twin modeling method of an aircraft engine rotor system according to claim 2, characterized in that: The measured vibration signal is obtained through an eddy current displacement sensor and an acceleration sensor.

4. The digital twin modeling method of an aircraft engine rotor system according to claim 1, characterized in that: Obtain the geometrical dimension parameters, material parameters, and load parameters of the rotor system, including: Obtain geometric dimension parameters from the geometric drawings or 3D models of the rotor system; Obtain material parameters from the grades of materials used for the rotating shaft and rotating disk; The load parameters are obtained according to the influence coefficient method.

5. The digital twin modeling method of an aircraft engine rotor system according to claim 1, characterized in that: The digital twin model includes the nonlinear factors of rolling bearings, the nonlinear factors of combined supports and the time-varying stiffness characteristics of the connection structure.

6. The digital twin modeling method of an aircraft engine rotor system according to claim 5, characterized in that: The nonlinear factors of rolling bearings are obtained through Hertz contact theory, elastic mechanics derivation and finite element method.

7. A real-time interactive digital twin of an aero-engine rotor system constructed using the digital twin modeling method of an engine rotor system as described in any one of claims 1 to 6.

8. A computer-readable storage medium, wherein a computer instruction set is stored in the computer-readable storage medium. When the computer instruction set is executed by a processor, the digital twin modeling method of the aircraft engine rotor system as described in any one of claims 1 to 6 is implemented.

Images