Transient response calculation method and system of rotating shaft under time-space coupled oil film distribution load

Abstract

The present invention discloses a method and system for calculating the transient response of a rotating shaft under a time-space coupled oil film distribution load, and relates to the technical field of transient response calculation. The method comprises: decoupling and decomposing the time-space coupled oil film distribution load to obtain a series of linear combinations of oil film sub-distribution loads that are independent of each other in terms of time history and oil film thickness spatial distribution function; fitting the oil film thickness spatial distribution function of the oil film sub-distribution load using a target orthogonal polynomial function to obtain a fitting coefficient; according to the fitting coefficient, the oil film sub-distribution load is equivalent to a concentrated load acting on a finite number of oil film load action points on the rotating shaft; based on the time series response analysis of the concentrated load, the transient response of the rotating shaft under the oil film sub-distribution load is calculated and linearly superposed to obtain the transient response of the rotating shaft under the time-space coupled oil film distribution load. The present invention alleviates the technical problem that the prior art cannot effectively deal with the relevant calculation of the sliding bearing oil film presenting the time-space coupled distribution load characteristics.

Description

Technical Field

[0001] The present invention relates to the technical field of transient response calculation, and in particular to a method and system for calculating the transient response of a rotating shaft under a time-space coupled oil film distribution load. Background Art

[0002] Sliding bearings are supporting components of high-power wind turbine gearbox transmission systems and are crucial to the stable operation of wind turbine equipment. The operating status of the main shaft of a wind turbine gearbox is an important monitoring indicator for the status monitoring of wind turbine equipment. Accurately obtaining its transient response to ensure the operating status of wind turbines is an indispensable link. The oil film load of sliding bearings presents spatiotemporal coupling characteristics. The time history function of the dynamic load distributed by the oil film is closely related to the position of the load, and the spatial distribution function also changes with time. It needs to be represented by variables with mutually coupled time and space dimensions. However, conventional transient response analysis methods are only for concentrated loads with a time dimension, and cannot effectively deal with the relevant calculations of sliding bearing oil films that present spatiotemporal coupling distribution load characteristics. Summary of the invention

[0003] The purpose of the present invention is to provide a method and system for calculating the transient response of a rotating shaft under a time-space coupled oil film distribution load in order to solve at least one of the above technical problems.

[0004] In the first aspect, an embodiment of the present invention provides a method for calculating the transient response of a rotating shaft under a time-space coupled oil film distribution load, comprising: decoupling and decomposing the oil film distribution load coupled with the time history associated with the oil film thickness change and the spatial distribution function to obtain a linear combination of a series of oil film sub-distributed loads whose time history and the oil film thickness spatial distribution function are independent of each other; fitting the oil film thickness spatial distribution function of the oil film sub-distributed load using a target orthogonal polynomial function to obtain the fitting coefficients of each of the oil film thickness spatial distribution functions under the target orthogonal polynomial function; according to the fitting coefficients, equating the oil film sub-distributed load to a concentrated load acting on a finite number of oil film load application points on the rotating shaft; calculating the transient response of the rotating shaft under the oil film sub-distributed load based on the oil film time history of the oil film sub-distributed load and the time series response analysis of the concentrated load; linearly superimposing the transient responses of the rotating shaft under each of the oil film sub-distributed loads to obtain the transient response of the rotating shaft under the time-space coupled oil film distribution load.

[0005] Furthermore, the oil film distribution load coupled with the time history associated with the change of oil film thickness and the spatial distribution function is decoupled and decomposed to obtain a series of linear combinations of oil film sub-distributed loads whose time history and the spatial distribution function of oil film thickness are independent of each other, including: establishing a covariance matrix of the oil film distribution load; decomposing the intrinsic eigenvalues ​​and intrinsic eigenvectors of the oil film distribution load according to the covariance matrix, wherein the intrinsic eigenvectors of the oil film distribution load are used as the spatial distribution function of oil film thickness; determining the principal coordinates of the oil film distribution load based on the intrinsic orthogonal decomposition algorithm, and using the principal coordinates as the oil film time history of the oil film distribution load; and decomposing the oil film distribution load into a series of linear combinations of the products of the spatial distribution function of oil film thickness and the corresponding oil film time history.

[0006] Furthermore, according to the covariance matrix, the intrinsic eigenvalues ​​and intrinsic eigenvectors of the oil film distribution load are decomposed, including: determining multiple intrinsic eigenvalues ​​of the covariance matrix based on the eigenequation of the covariance matrix; and calculating the eigenvectors of the covariance matrix based on the maximum eigenevalue among the multiple eigenevalues.

[0007] Furthermore, after obtaining a linear combination of a series of oil film sub-distribution loads that are independent of each other in terms of time history and spatial distribution function of oil film thickness, the method further includes: linearly superimposing the separated series of oil film sub-distribution loads that are independent of each other in terms of time history and spatial distribution function of oil film thickness to obtain a superimposed oil film distribution load; and determining the number of groups of the oil film sub-distribution loads of the intrinsic orthogonal decomposition based on the relative error between the superimposed oil film distribution load and the oil film distribution load.

[0008] Furthermore, the target orthogonal polynomial function includes a Chebyshev polynomial basis function.

[0009] Furthermore, according to the fitting coefficient, the oil film sub-distributed load is equivalent to a concentrated load acting on a finite number of oil film load action points on the rotating shaft, including: converting each group of oil film thickness spatial distribution functions to a finite number of action points on the rotating shaft to obtain the concentrated load on the finite number of action points on the rotating shaft.

[0010] Furthermore, the finite number of oil film load action points on the rotating shaft are multiple oil film action points on the main shaft of the wind turbine gearbox coupled to the sliding bearing.

[0011] In a second aspect, an embodiment of the present invention further provides a transient response calculation system for a rotating shaft under a time-space coupled oil film distribution load, comprising: a decomposition module, a fitting module, a conversion module, a calculation module and a superposition module; wherein the decomposition module is used to decouple and decompose the oil film distribution load coupled with the time history associated with the oil film thickness change and the spatial distribution function, and obtain a linear combination of a series of oil film sub-distribution loads whose time history and the oil film thickness spatial distribution function are independent of each other; the fitting module is used to fit the oil film thickness spatial distribution function of the oil film sub-distribution load using a target orthogonal polynomial function, and obtain to the fitting coefficients of each of the oil film thickness spatial distribution functions under the target orthogonal polynomial function; the conversion module is used to convert the oil film sub-distributed load into a concentrated load acting on a finite number of oil film load application points on the shaft according to the fitting coefficients; the calculation module is used to calculate the transient response of the shaft under the oil film sub-distributed load based on the oil film time history of the oil film sub-distributed load and the time series response analysis of the concentrated load; the superposition module is used to linearly superimpose the transient responses of the shaft under each of the oil film sub-distributed loads to obtain the transient response of the shaft under the time-space coupled oil film distribution load.

[0012] In a third aspect, an embodiment of the present invention further provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method described in the first aspect when executing the computer program.

[0013] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and when the computer instructions are executed by a processor, the method described in the first aspect above is implemented.

[0014] The present invention provides a method and system for calculating the transient response of a rotating shaft under a time-space coupled oil film distribution load, introduces an intrinsic orthogonal decomposition algorithm and a Chebyshev polynomial basis function to fit the time-space coupled oil film distribution load as a series of concentrated dynamic loads acting on limited action points of the rotating shaft, and can use a conventional concentrated load transient response analysis method to calculate the transient response of a main shaft of a wind turbine gearbox under an oil film sub-distributed load, thereby improving the speed of transient response calculation, expanding the application scope of conventional concentrated load transient analysis methods, and alleviating the technical problem in the prior art that it cannot effectively cope with the related calculation of the sliding bearing oil film presenting the time-space coupled distribution load characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 A flow chart of a method for calculating the transient response of a rotating shaft under a time-space coupled oil film distribution load provided by an embodiment of the present invention;

[0017] Figure 2 A flow chart of another method for calculating the transient response of a rotating shaft under a time-space coupled oil film distribution load provided by an embodiment of the present invention;

[0018] Figure 3 A schematic diagram of the structural dimensions of a main shaft model of a high-power wind turbine gearbox provided by an embodiment of the present invention;

[0019] Figure 4 A schematic diagram of a finite element model of a main shaft model of a high-power wind turbine gearbox provided by an embodiment of the present invention;

[0020] Figure 5 A schematic diagram of the spatial distribution basis function and the time basis function of three groups of oil film sub-distribution loads provided by an embodiment of the present invention;

[0021] Figure 6 A schematic diagram of a real oil film distribution load provided by an embodiment of the present invention;

[0022] Figure 7 A schematic diagram of superposition of three groups of oil film sub-distribution loads provided in an embodiment of the present invention;

[0023] Figure 8 A schematic diagram of an error of POD decomposition provided by an embodiment of the present invention;

[0024] Fig. 9 A schematic diagram of the results of fitting three groups of oil film thickness spatial distribution functions using a Chebyshev polynomial basis function provided in an embodiment of the present invention;

[0025] Fig.10 A schematic diagram of the results of three groups of oil film sub-distribution loads provided by an embodiment of the present invention;

[0026] Fig.11 A schematic diagram of the results of concentrated loads on five load points where three groups of oil film sub-distributed loads are equivalent provided by an embodiment of the present invention;

[0027] Fig.12A schematic diagram of the results of comparative analysis of displacement responses of nodes 6-8 under an oil film distributed load, an oil film sub-distributed load, and an equivalent concentrated load provided by an embodiment of the present invention;

[0028] Fig.13 A schematic diagram of the results of comparative analysis of displacement responses of nodes 9-11 under an oil film distributed load, an oil film sub-distributed load, and an equivalent concentrated load provided by an embodiment of the present invention;

[0029] Fig.14 A schematic diagram of a transient response calculation system for a rotating shaft under a time-space coupled oil film distribution load provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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 are within the scope of protection of the present invention.

[0031] Embodiment 1

[0032] Figure 1 FIG. 1 is a flow chart of a method for calculating the transient response of a rotating shaft under a time-space coupled oil film distribution load according to an embodiment of the present invention. Figure 1 As shown, the method specifically comprises the following steps:

[0033] Step S102 , decoupling and decomposing the oil film distribution load coupled with the time history associated with the oil film thickness change and the spatial distribution function, and obtaining a linear combination of a series of oil film sub-distribution loads whose time history and the oil film thickness spatial distribution function are independent of each other.

[0034] Step S104 , fitting the oil film thickness spatial distribution function of the oil film sub-distributed loads by using the target orthogonal polynomial function to obtain the fitting coefficients of each oil film thickness spatial distribution function under the target orthogonal polynomial function.

[0035] Step S106: Based on the fitting coefficient, the oil film sub-distributed load is equivalent to a concentrated load acting on a finite number of oil film load action points on the shaft.

[0036] Step S108, based on the oil film time history of the oil film sub-distributed load and the time series response analysis of the concentrated load, calculate the transient response of the shaft under the oil film sub-distributed load.

[0037] Step S110 , linearly superimposing the transient responses of the shaft under each oil film sub-distributed load to obtain the transient response of the shaft under the time-space coupled oil film distributed load.

[0038] Specifically, step S102 includes the following steps:

[0039] Step S1021, establishing the covariance matrix of the oil film distributed load.

[0040] Step S1022, decomposing the intrinsic eigenvalues ​​and intrinsic eigenvectors of the oil film distributed load according to the covariance matrix, wherein the intrinsic eigenvectors of the oil film distributed load are used as the spatial distribution function of the oil film thickness.

[0041] Specifically, first, based on the eigenvalues ​​of the covariance matrix, multiple eigenvalues ​​of the covariance matrix are determined; then, based on the maximum eigenvalue among the multiple eigenvalues, the eigenvector of the covariance matrix is ​​calculated.

[0042] Step S1023, based on the proper orthogonal decomposition algorithm, determine the principal coordinates of the oil film distributed load, and use the principal coordinates as the oil film time history of the oil film distributed load.

[0043] Step S1024, decomposing the oil film distribution load into a linear combination of a series of products of the oil film thickness spatial distribution function and the corresponding oil film time history.

[0044] Figure 2 FIG. 1 is a flow chart of another method for calculating the transient response of a rotating shaft under a time-space coupled oil film distribution load provided according to an embodiment of the present invention. Figure 2 As shown, in the embodiment of the present invention, the oil film distribution load coupled with the oil film time history and the spatial distribution function can be represented as a two-dimensional matrix F(t,h(z)) containing time and oil film thickness representations because it contains two dimensions of time and space. The two-dimensional matrix has N rows and M columns, and each row represents the size of the oil film load associated with the oil film thickness at a certain time point of the coupled oil film distribution load.

[0045]

[0046] Where: F(t,h(z)) is the oil film distribution load coupled with the time history of the oil film and the spatial distribution function, the length of the spatial distribution function of the oil film thickness is M discrete points, and the length of the oil film time history is N discrete points.

[0047] First, the covariance matrix c of the time-space coupled oil film distribution load is established * As shown in formula (2):

[0048] c * =1 / N·(F'(t,h(z)))·F(t,h(z))) (2)

[0049] Secondly, through c *·V=D·V The intrinsic eigenvalue D and the intrinsic eigenvector V of the time-space coupled oil film distribution load are decomposed, and the intrinsic eigenvector V of the oil film distribution load is obtained through the intrinsic characteristic root D of the oil film distribution load. The intrinsic eigenvector V of the oil film distribution load represents the spatial distribution function h(z) of the oil film thickness, which can be expressed as:

[0050] V=[h1(z),h2(z),…,h M (z)] (3)

[0051] Then, according to the proper orthogonal decomposition (POD) algorithm, the principal coordinates a are obtained. m (t), oil film time history of oil film distributed load l k (t) is the principal coordinate a m (t), the time history can be expressed as follows:

[0052] {l(t)}=V T F(t,h(z)) (4)

[0053] The oil film distribution load that changes with time history and spatial distribution function is divided into M oil film time history l k (t) and the spatial distribution function of oil film thickness h k The superposition of the products of (z) and (t) that are independent of each other, the time-space coupled oil film distribution load F(t,h(z)) can be expressed as:

[0054]

[0055] Where: l k (t) represents the kth oil film time history, h k (z) is represented as the spatial distribution function of the kth oil film thickness.

[0056] Preferably, if Figure 2 As shown, after step S102, the method further includes:

[0057] The oil film distribution loads which are independent of each other in a series of separated time histories and oil film thickness spatial distribution functions are linearly superimposed to obtain the superimposed oil film distribution loads;

[0058] Based on the relative error between the superimposed oil film distribution load and the oil film distribution load, the number of groups of the oil film sub-distribution load of the proper orthogonal decomposition is determined.

[0059] Specifically, firstly, the initial value M of the number of groups is set, and based on the POD algorithm, the oil film distribution load is decomposed into M groups of oil film sub-distribution loads whose oil film time history and oil film thickness spatial distribution function are independent of each other, and then the M groups of oil film sub-distribution loads are superimposed to obtain the superimposed oil film distribution load, and finally the relative error between the superimposed oil film distribution load and the oil film distribution load is calculated, and if the relative error is greater than the preset error threshold, the initial value M of the number of groups is adjusted. For example, one group is added, and then the above steps are continuously executed in a loop until the relative error is less than the preset error threshold.

[0060] Preferably, the target orthogonal polynomial function comprises a Chebyshev polynomial basis function.

[0061] Specifically, step S106 further includes: converting each group of oil film thickness spatial distribution functions to a finite number of action points on the rotating shaft to obtain concentrated loads acting on the finite number of action points on the rotating shaft. The finite number of oil film load action points on the rotating shaft are multiple oil film action points on the main shaft of the wind turbine gearbox coupled to the sliding bearing.

[0062] In the embodiment of the present invention, the oil film thickness spatial distribution function h k (z) can be approximated by a combination of a series of Chebyshev polynomial basis functions. Then equation (5) becomes as follows:

[0063]

[0064] Where: R i is the i-th Chebyshev polynomial basis function, a ki is the coefficient before the i-th Chebyshev polynomial basis function of the k-th oil film distribution space function.

[0065] A group of oil film sub-distributed loads that are independent in time and space are equivalent to n oil film load action points on the main shaft of the wind turbine gearbox, r ni is the equivalent amplitude coefficient of the ith Chebyshev polynomial basis function equivalent to the nth node, and its equivalent load conversion is as follows:

[0066]

[0067] The M groups of oil film sub-distribution loads are linearly superimposed into the oil film distribution load, and the oil film distribution load is converted into:

[0068]

[0069] Where: A nM is the equivalent amplitude coefficient of the Mth spatial distribution function at the nth load node.

[0070] The oil film thickness spatial distribution function in the oil film sub-distributed load is fitted by Chebyshev polynomial basis function, so that the oil film sub-distributed load is equivalent to the concentrated load on n finite oil film load action points on the wind turbine gearbox main shaft coupled with the sliding bearing, so that the conventional concentrated load transient response analysis method can be used to calculate the transient response of the wind turbine gearbox main shaft under the oil film sub-distributed load. The transient response of the wind turbine gearbox main shaft under the oil film time-space coupled distributed load can be obtained by linearly superimposing the transient response of the wind turbine gearbox main shaft under each oil film sub-distributed load.

[0071] Embodiment 2

[0072] The present invention takes a main shaft model of a high-power wind turbine gearbox as an example to illustrate a specific implementation of a method for calculating the transient response of a rotating shaft under a time-space coupled oil film distribution load provided by an embodiment of the present invention as follows.

[0073] Figure 3 is a schematic diagram of the structural dimensions of a main shaft model of a high-power wind turbine gearbox provided in an embodiment of the present invention. Figure 4 FIG. 1 is a schematic diagram of a finite element model of a main shaft model of a high-power wind turbine gearbox provided according to an embodiment of the present invention. Figure 3 and Figure 4 As shown, the geometric dimensions are marked in the figure. The material properties of the main shaft of the high-power wind turbine gearbox are the same, with an elastic modulus of 125 GPa, a Poisson's ratio of 0.335, and a density of 8850 kg / m 3 Assuming that the oil film load of the sliding bearing of the high-power wind turbine gearbox presents the actual oil film distribution load expression: F(t, h(z)) = (400sin(z 2 t)+600sin(z 1 t 2 )+1000sin(t 3 ))*1000,t∈[0,2]|s,z∈[0,0.2]|m, acts vertically along the y direction on the left end area (0~200mm) of the main shaft of the high-power wind turbine gearbox.

[0074] The proper orthogonal decomposition (POD) algorithm is used to decompose the oil film into a linear combination of oil film sub-distribution loads whose time history and spatial distribution functions are independent of each other. Figure 5 The spatial distribution basis functions and time basis functions of the three groups of oil film sub-distribution loads are shown in FIG.

[0075] The three groups of oil film spatial distribution functions and time history linear combinations that have been decomposed into time and space independent ones are compared with the previously assumed oil film distribution loads. Figure 6 is a schematic diagram of a real oil film distribution load provided according to an embodiment of the present invention. Figure 7 is a schematic diagram of superposition of three groups of oil film sub-distribution loads provided according to an embodiment of the present invention, Figure 8FIG. 1 is a schematic diagram of an error of POD decomposition provided according to an embodiment of the present invention. Figure 6-8 As shown, it can be seen that its absolute error fluctuates between -100N and 100N, and its error is very small relative to the actual oil film distributed load. And the overall relative error is calculated to be only RE = 3.18E-5, which proves the accuracy and effectiveness of the POD decomposition algorithm to decouple the oil film distributed load.

[0076] The coefficient a of the Chebyshev polynomial basis function is obtained by fitting ki As shown in Table 1 below, the six coefficients of the first group of oil film spatial distribution functions h1(z) fitted by Chebyshev polynomial basis functions are a 11 =-0.0994, a 12 =-0.0067, a 13 =-6.78E-05, a 14 =1.67E-05, a 15 =-3.24E-07, a 16 =-2.89E-08; The six coefficients of the second group of oil film spatial distribution function h2(z) fitted by Chebyshev polynomial basis function are a 21 =0.0041, a 22 =-0.1702, a 23 =0.0004, a 24 =0.0006, a 25 =-7.62E-06, a 26 =-6.77E-07; The 6 coefficients of the third group of oil film spatial distribution function h3(z) fitted by Chebyshev polynomial basis function are a 31 =-0.0518, a 32 =-0.0114, a 33 =-0.1622, a 34 =-0.0197, a 35 =0.0004, a 36 =4.15E-05.

[0077] Table 1 Coefficients before each Chebyshev polynomial basis function

[0078]

[0079] Fig. 9 1 is a schematic diagram of the results of fitting three sets of oil film thickness spatial distribution functions using a Chebyshev polynomial basis function provided by an embodiment of the present invention. Fig. 9It can be seen that the three groups of fitted oil film spatial distribution functions are very consistent with the crude oil film spatial distribution function. The first group of oil film spatial distribution functions and the second group of oil film spatial distribution functions show a linear function relationship, and the third group of oil film spatial distribution functions show a quadratic function relationship. The relative errors of the fitting of the three groups of oil film spatial distribution functions h1(z), h2(z), and h3(z) are calculated to be RE1=5.01E-9, RE2=1.17E-7, and RE3=4.61E-6, respectively; the effectiveness and accuracy of the Chebyshev polynomial basis function fitting the oil film spatial distribution function are proved.

[0080] The oil film spatial distribution function is converted to the effective load action point of the wind turbine gearbox main shaft using the Chebyshev polynomial basis function, and the equivalent amplitude coefficient can be obtained as shown in Table 2:

[0081] Table 2 Equivalent coefficients of Chebyshev polynomial basis function fitting

[0082]

[0083]

[0084] Convert the oil film distributed load into a finite concentrated load. ki Use formula (7) to calculate the equivalent coefficient A of the oil film space function: nM The calculated equivalent coefficients of the oil film spatial distribution function are shown in Table 2. The equivalent coefficients of the spatial distribution function of the finite concentrated load action point 1 are A 11 =-0.0928, A 12 =0.1741, A 13 =-0.1834; the equivalent coefficients of the spatial distribution function of the load action point 2 are A 21 =-0.1921, A 22 =0.1791, A 23 =0.0284; the equivalent coefficients of the spatial distribution function of the load action point 3 are A 31 =-0.1988, A 32 =0.0073, A 33 =0.2198; the equivalent coefficients of the spatial distribution function of the load action point 4 are A 41 =-0.2056, A 42 =-0.1636, A 43 =-0.1651; the equivalent coefficients of the spatial distribution function of the load action point 5 are A 51 =-0.1062, A 52 =-0.1651, A 53 =0.2198. Fig.10The following are three groups of oil film distribution loads, which are converted into Fig.11 The three groups of oil film distributed loads shown are equivalent to concentrated loads on five load points.

[0085] like Figure 3 The equivalent oil film sub-distributed loads of the five concentrated load points shown in nodes 1-5 can be expressed as follows: Node 1 -0.0928*l1(t)+0.1741*l2(t)-0.1834*l3(t); Node 2 -0.1921*l1(t)+0.1791*l2(t)+0.0284*l3(t); Node 3 -0.1988*l1(t)+0.0073*l2(t)+0.2198*l3(t); Node 4 -0.2056*l1(t)-0.1636*l2(t)+0.0843*l3(t); Node 5 -0.1062*l1(t)-0.1651*l2(t)-0.2454*l3(t). The equivalent oil film sub-distributed loads of the five nodes are applied to the nodes corresponding to the main axis respectively, and the transient displacement response of each node of the main axis is calculated by the concentrated load transient response analysis method, and compared with the transient response obtained by the finite element analysis software, such as Fig.12 The figure shows the comparative analysis of the displacement response of nodes 6-8 under oil film distributed load, oil film sub-distributed load and equivalent concentrated load. Fig.13 The figure shows the comparative analysis of the displacement responses of nodes 9-11 under the oil film distributed load, oil film sub-distributed load, and equivalent concentrated load. It can be seen that the transient responses under the oil film distributed load and the oil film sub-distributed load are equal, proving the effectiveness of the decoupling of the time-space coupled oil film distributed load. The transient response under the oil film distributed load and the transient response under the equivalent concentrated load are both coefficient-related, which conforms to the deformation law of the structure under the distributed load and the concentrated load, proving the effectiveness of converting the oil film sub-distributed load into a concentrated load.

[0086] From the above description, it can be seen that the embodiment of the present invention provides a method for calculating the transient response of a rotating shaft under a time-space coupled oil film distribution load, which has the following technical effects compared with the prior art:

[0087] 1) The present invention decouples the spatiotemporal coupled oil film distribution load based on the proper orthogonal decomposition (POD) algorithm into a linear combination of oil film sub-distribution loads whose time history and spatial distribution functions are independent of each other, thereby reducing the particularity and difficulty of the complex coupling relationship of the spatiotemporal coupled oil film distribution load.

[0088] 2) The present invention fits the oil film spatial distribution function based on the Chebyshev polynomial basis function, converts the oil film sub-distribution load into a series of concentrated loads, and improves the efficiency of transient response calculation under the time-space coupled oil film distribution load.

[0089] 3) The method of the present invention enhances the engineering practicability of the transient response analysis method of concentrated loads.

[0090] Embodiment 3

[0091] Fig.14 Schematic diagram of a transient response calculation system for a rotating shaft under a time-space coupled oil film distribution load provided by an embodiment of the present invention. Fig.14 As shown, the system includes: a decomposition module 10, a fitting module 20, a conversion module 30, a calculation module 40 and a superposition module 50.

[0092] Specifically, the decomposition module 10 is used to decouple the oil film distribution load coupled with the time history associated with the oil film thickness change and the spatial distribution function to obtain a linear combination of a series of oil film sub-distribution loads that are independent of each other in terms of time history and oil film thickness spatial distribution function.

[0093] The fitting module 20 is used to fit the oil film thickness spatial distribution function of the oil film sub-distributed load using the target orthogonal polynomial function to obtain the fitting coefficient of each oil film thickness spatial distribution function under the target orthogonal polynomial function.

[0094] Preferably, the target orthogonal polynomial function comprises a Chebyshev polynomial basis function.

[0095] The conversion module 30 is used to convert the oil film sub-distributed load into a concentrated load acting on a finite number of oil film load action points on the rotating shaft according to the fitting coefficient.

[0096] Preferably, the limited action points include a plurality of oil film action points on the main shaft of the wind turbine gearbox coupled to the sliding bearing.

[0097] The calculation module 40 is used to calculate the transient response of the shaft under the oil film sub-distributed load based on the oil film time history of the oil film sub-distributed load and the time series response analysis of the concentrated load.

[0098] The superposition module 50 is used to linearly superimpose the transient responses of the shaft under each oil film sub-distribution load to obtain the transient response of the shaft under the time-space coupled oil film distribution load.

[0099] Specifically, the decomposition module 10 is also used for:

[0100] Establish the covariance matrix of oil film distribution load;

[0101] According to the covariance matrix, the intrinsic eigenvalue and intrinsic eigenvector of the oil film distribution load are decomposed, wherein the intrinsic eigenvector of the oil film distribution load is used as the spatial distribution function of the oil film thickness;

[0102] Based on the proper orthogonal decomposition algorithm, the principal coordinates of the oil film distribution load are determined, and the principal coordinates are used as the oil film time history of the oil film distribution load.

[0103] The oil film distribution load is decomposed into a linear combination of the product of a series of oil film thickness spatial distribution functions and the corresponding oil film time history.

[0104] An embodiment of the present invention further provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method provided by the present invention when executing the computer program.

[0105] An embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and when the computer instructions are executed by a processor, the method provided by the present invention is implemented.

[0106] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0107] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for calculating the transient response of a rotating shaft under a time-space coupled oil film distribution load. It is characterized in that include: The oil film distribution load coupled with the time history and spatial distribution function associated with the oil film thickness change is decoupled and decomposed to obtain a series of linear combinations of oil film sub-distribution loads whose time history and spatial distribution function of oil film thickness are independent of each other. The oil film distribution load coupled with the time history associated with the oil film thickness change and the spatial distribution function is decoupled and decomposed to obtain a series of linear combinations of oil film sub-distribution loads whose time history and the oil film thickness spatial distribution function are independent of each other, including: Establishing a covariance matrix of the oil film distribution load; Decomposing the intrinsic eigenvalue and the intrinsic eigenvector of the oil film distributed load according to the covariance matrix, wherein the intrinsic eigenvector of the oil film distributed load is used as a spatial distribution function of the oil film thickness; Based on the intrinsic orthogonal decomposition algorithm, the principal coordinates of the oil film distributed load are determined, and the principal coordinates are used as the oil film time history of the oil film distributed load; Decomposing the oil film distribution load into a series of linear combinations of products of the oil film thickness spatial distribution functions and the corresponding oil film time histories; Using a target orthogonal polynomial function to fit the oil film thickness spatial distribution function of the oil film sub-distributed load, to obtain the fitting coefficients of each of the oil film thickness spatial distribution functions under the target orthogonal polynomial function; wherein the target orthogonal polynomial function includes a Chebyshev polynomial basis function; According to the fitting coefficient, the oil film sub-distributed load is equivalent to a concentrated load acting on a finite number of oil film load action points on the rotating shaft; Based on the oil film time history of the oil film sub-distributed load and the time series response analysis of the concentrated load, calculating the transient response of the shaft under the oil film sub-distributed load; The transient responses of the shaft under the oil film sub-distributed loads are linearly superimposed to obtain the transient response of the shaft under the time-space coupled oil film distributed loads.

2. The method according to claim 1, Features: According to the covariance matrix, the intrinsic eigenvalue and the intrinsic eigenvector of the oil film distributed load are decomposed, including: Determining a plurality of eigenvalues ​​of the covariance matrix based on an eigenvalue equation of the covariance matrix; An eigenvector of the covariance matrix is ​​calculated based on a maximum eigenvalue among the plurality of eigenvalues.

3. The method according to claim 1, Features: After obtaining a series of linear combinations of oil film sub-distribution loads that are independent of each other in terms of time history and oil film thickness spatial distribution function, the method further includes: Linearly superimposing the separated series of oil film sub-distribution loads that are independent of each other in terms of time history and oil film thickness spatial distribution function to obtain a superimposed oil film distribution load; Based on the relative error between the superimposed oil film distributed load and the oil film distributed load, the number of groups of the oil film sub-distributed loads of the intrinsic orthogonal decomposition is determined.

4. The method according to claim 1, Features: According to the fitting coefficient, the oil film sub-distributed load is equivalent to a concentrated load acting on a finite number of oil film load action points on the shaft, including: The spatial distribution functions of each group of oil film thickness are converted to a finite number of action points on the rotating shaft, and the concentrated loads acting on the finite number of action points on the rotating shaft are obtained.

5. The method according to claim 1 or 4, Features: The finite number of oil film load action points on the rotating shaft are multiple oil film action points on the main shaft of the wind turbine gearbox coupled with the sliding bearing.

6. A transient response calculation system for a rotating shaft under a time-space coupled oil film distribution load, It is characterized in that include: Decomposition module, fitting module, conversion module, calculation module and superposition module; among them, The decomposition module is used to decouple and decompose the oil film distribution load coupled with the time history associated with the oil film thickness change and the spatial distribution function to obtain a linear combination of a series of oil film sub-distribution loads whose time history and the oil film thickness spatial distribution function are independent of each other; The oil film distribution load coupled with the time history associated with the oil film thickness change and the spatial distribution function is decoupled and decomposed to obtain a series of linear combinations of oil film sub-distribution loads whose time history and the oil film thickness spatial distribution function are independent of each other, including: Establishing a covariance matrix of the oil film distribution load; Decomposing the intrinsic eigenvalue and the intrinsic eigenvector of the oil film distributed load according to the covariance matrix, wherein the intrinsic eigenvector of the oil film distributed load is used as a spatial distribution function of the oil film thickness; Based on the intrinsic orthogonal decomposition algorithm, the principal coordinates of the oil film distributed load are determined, and the principal coordinates are used as the oil film time history of the oil film distributed load; Decomposing the oil film distribution load into a series of linear combinations of products of the oil film thickness spatial distribution functions and the corresponding oil film time histories; The fitting module is used to fit the oil film thickness spatial distribution function of the oil film sub-distributed load using a target orthogonal polynomial function to obtain the fitting coefficients of each of the oil film thickness spatial distribution functions under the target orthogonal polynomial function; wherein the target orthogonal polynomial function includes a Chebyshev polynomial basis function; The conversion module is used to convert the oil film sub-distributed load into a concentrated load acting on a finite number of oil film load action points on the rotating shaft according to the fitting coefficient; The calculation module is used to calculate the transient response of the shaft under the oil film sub-distributed load based on the oil film time history of the oil film sub-distributed load and the time series response analysis of the concentrated load; The superposition module is used to linearly superimpose the transient responses of the rotating shaft under each of the oil film sub-distributed loads to obtain the transient response of the rotating shaft under the time-space coupled oil film distributed load.

7. An electronic device, It is characterized in that include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method according to any one of claims 1 to 5 when executing the computer program.

8. A computer-readable storage medium, It is characterized in that The computer-readable storage medium stores computer instructions, and when the computer instructions are executed by a processor, the method according to any one of claims 1 to 5 is implemented.

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