CN112231954B - Method for establishing digital twin model of hydraulic structure - Google Patents

Abstract

The invention discloses a method for establishing a digital twin model of a hydraulic structure, which comprises the following steps: s1, constructing a finite element model according to known physical parameters of a hydraulic structure; s2, acquiring self-vibration frequency and vibration mode information of a hydraulic structure in the actual operation process of 1 st order and above, wherein the self-vibration frequency and vibration mode information is obtained by calculation of a finite element model; s3, establishing a deterministic power model updating target equation for physical parameters of the hydraulic structure to be adjusted according to the data obtained in the step S2; s4, acquiring a value of a physical parameter of the hydraulic structure to be adjusted, which corresponds to the minimum value of the deterministic power model updating target equation, and finishing updating of the finite element model, namely finishing establishment of the hydraulic structure digital twin model. The method only needs to consider the basic information of the hydraulic structure, and can automatically complete the update of the finite element model according to the basic information and the change process, thereby realizing the establishment of the digital twin model of the hydraulic structure.

Description

A method for establishing digital twin models of hydraulic structures

Technical field

The invention relates to the field of computer simulation, and specifically relates to a method for establishing a digital twin model of a hydraulic structure.

Background technique

Digital twins make full use of methods based on mathematical models, sensor updates, big data, machine learning, probability analysis and other methods to integrate multi-disciplinary, multi-physical quantities, multi-scale, multi-probability simulation processes to achieve complete mapping of structures and virtual models, thereby completing Technology for full life cycle management of simulation objects. Digital twin is a concept that transcends reality and can be regarded as a digital mapping system of one or more important and interdependent equipment systems. The key to digital twin technology is to create a digital twin model of the application object, that is, the physical entity, the virtual entity and the connection between the two. How to accurately create a digital model that can accurately reflect the structural characteristics based on the physical parameters of the entity structure mastered by testing equipment, sensors, big data and other means. At the same time, the model can adjust the corresponding parameters in a timely manner based on the operating status of the structure to maintain consistency. The consistent running status of the physical model is a difficult problem to be solved by the digital twin model.

The overall characteristics of my country's hydraulic structures are large size, complex structure, and changing construction environment factors. As of the end of 2018, among the top 100 dams in the world that have been built or are under construction, my country accounts for 30 dams; the height is more than 200 meters. There are 82 dams, 25 of which are in my country. With the vigorous development of my country's hydropower industry in the past 20 years, a number of high dams or ultra-high dams have been constructed one after another. Therefore, if you want to establish a digital twin model for this type of hydraulic structure, you need to consider not only the characteristics of the structure itself, but also the impact of environmental factors and operating conditions. It is very difficult to establish an accurate digital model, and it requires its adaptive and timely It is even more difficult to adjust the corresponding parameters to maintain the same operating status as the physical model.

Contents of the invention

In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for establishing a digital twin model of a hydraulic structure, which solves the problem of difficulty in establishing a digital twin model of an existing hydraulic structure.

In order to achieve the above-mentioned object of the invention, the technical solutions adopted by the present invention are:

A method for establishing a digital twin model of a hydraulic structure is provided, which includes the following steps:

S1. Based on finite element software, build a finite element model based on the known physical parameters of the hydraulic structure;

S2. Obtain the first-order and above natural vibration frequency and vibration shape information of the hydraulic structure during actual operation, obtain the natural vibration frequency and vibration shape information calculated by the finite element model, and select the physical parameters of the hydraulic structure that need to be adjusted. ;

S3. Establish a deterministic dynamic model to update the target equation for the physical parameters of the hydraulic structure that need to be adjusted based on the data obtained in step S2;

S4. Obtain the values of the physical parameters of the hydraulic structure that need to be adjusted corresponding to the minimum value of the deterministic dynamic model update objective equation, and complete the update of the finite element model, that is, the establishment of the digital twin model of the hydraulic structure.

Further, the specific method of selecting the physical parameters of the hydraulic structure that needs to be adjusted in step S2 includes the following sub-steps:

S2-1. Obtain all material parameters of the hydraulic structure. Use the single variable method in the finite element model to increase one material parameter by 20% at a time until the material parameter increases to 160% of the original value. Obtain each increase. The natural frequency of the finite element model corresponding to the material parameters;

S2-2. Obtain the corresponding natural frequency change rate based on the natural frequency of the finite element model after each material parameter increases;

S2-3. Sort the corresponding material parameters in the order of natural frequency change rate from large to small, and select the first n material parameters as the physical parameters of the hydraulic structure that need to be adjusted.

Further, in step S2-1, the natural frequency of the finite element model is the first 3 to 6 order natural frequencies in the finite element model.

Further, the deterministic dynamic model update target equation in step S3 is specifically:

f(θ)＝r(θ) ^T Wr(θ)+(θ-θ ₀ ) ^T W _θ (θ-θ ₀ )

where f(θ) is the value of the deterministic dynamic model update objective equation; r(θ) is the residual vector; r _f (θ) is the frequency residual vector, including the frequency residual vector of each order; r _s (θ) is the mode shape Residual vectors, including the residual vector of each mode mode; W is the diagonal weight matrix; W _θ is the diagonal regularization weight matrix; θ is the physical parameter of the hydraulic structure that needs to be adjusted; θ ₀ is the value in the finite element model The current values of the physical parameters of the hydraulic structure that need to be adjusted; (·) ^T is the transpose of the matrix; is the i-th order frequency residual vector of the hydraulic structure; λ _i (θ) is the i-th order frequency calculated by the finite element model based on the physical parameters of the hydraulic structure that currently need to be adjusted;/> is the measured i-th order frequency of the hydraulic structure;/> is the residual vector of the i-th vibration mode of the hydraulic structure; φ ⁱ (θ) is the i-th overall mode shape calculated by the finite element model based on the physical parameters of the hydraulic structure that currently need to be adjusted; The mode shape of each measuring point of the i-th order calculated for the finite element model based on the physical parameters of the hydraulic structure that currently needs to be adjusted;/> is the measured i-th overall vibration shape of the hydraulic structure;/> is the measured mode shape of each measuring point of the i-th order of the hydraulic structure.

Further, in step S4, the specific method of obtaining the values of the physical parameters of the hydraulic structure that need to be adjusted corresponding to the minimum value of the deterministic dynamic model update objective equation is:

Obtain the values of the physical parameters of the hydraulic structure that need to be adjusted corresponding to the minimum value of the deterministic dynamic model update objective equation through MATLAB.

The beneficial effects of the present invention are: this method only needs to consider the basic information of the hydraulic structure, and can automatically complete the update of the finite element model based on the basic information and the change process, thereby realizing the establishment of a digital twin model of the hydraulic structure.

Description of the drawings

Figure 1 is a schematic flow diagram of the present invention;

Figure 2 is a schematic diagram of the finite element model of a gravity dam release dam in the embodiment;

Figure 3 is a schematic diagram of the first-order vibration shape in the embodiment;

Figure 4 is a schematic diagram of the second-order vibration shape in the embodiment;

Figure 5 is a schematic diagram of the third-order vibration shape in the embodiment;

Figure 6 is a schematic diagram of the first three measured vibration shapes;

Figure 7 shows the natural vibration frequency of the finite element model corresponding to some material parameters in the embodiment.

Detailed ways

The specific embodiments of the present invention are described below to facilitate those skilled in the art to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the technical field, as long as various changes These changes are obvious within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions and creations utilizing the concept of the invention are protected.

As shown in Figure 1, the establishment method of the digital twin model of the hydraulic structure includes the following steps:

S1. Based on finite element software, build a finite element model based on the known physical parameters of the hydraulic structure;

S2. Obtain the natural frequency and vibration shape information of the first order and above of the hydraulic structure during actual operation, obtain the natural frequency and vibration shape information calculated by the finite element model, and select the physical parameters of the hydraulic structure that need to be adjusted. ;

S3. Establish a deterministic dynamic model to update the target equation for the physical parameters of the hydraulic structure that need to be adjusted based on the data obtained in step S2;

S4. Obtain the values of the physical parameters of the hydraulic structure that need to be adjusted corresponding to the minimum value of the deterministic dynamic model update objective equation, and complete the update of the finite element model, that is, the establishment of the digital twin model of the hydraulic structure.

Large hydraulic structures are often composed of a variety of materials, and each material has different material parameters. If all material parameters are adjusted, there will generally be two results: (1) Time-consuming, and the number of iterations will increase with the material parameters. The increase increases with the index. (2) Diversity of results, more than one optimal solution may appear for a material parameter. Therefore, in the specific implementation process, the specific method of selecting the physical parameters of the hydraulic structure that needs to be adjusted in step S2 includes the following sub-steps:

S2-1. Obtain all material parameters of the hydraulic structure. Use the single variable method in the finite element model to increase one material parameter by 20% at a time until the material parameter increases to 160% of the original value. Obtain each increase. The natural frequency of the finite element model corresponding to the material parameters; the natural frequency of the finite element model is the first 3 to 6 order natural frequencies in the finite element model;

S2-2. Obtain the corresponding natural frequency change rate based on the natural frequency of the finite element model after each material parameter increases;

S2-3. Sort the corresponding material parameters in the order of natural frequency change rate from large to small, and select the first n material parameters as the physical parameters of the hydraulic structure that need to be adjusted. The value of n can depend on the specific situation.

The deterministic dynamic model update objective equation in step S3 is specifically:

f(θ)＝r(θ) ^T Wr(θ)+(θ-θ ₀ ) ^T W _θ (θ-θ ₀ )

where f(θ) is the value of the deterministic dynamic model update objective equation; r(θ) is the residual vector; r _f (θ) is the frequency residual vector, including the frequency residual vector of each order; r _s (θ) is the mode shape Residual vectors, including the residual vector of each mode mode; W is the diagonal weight matrix; W _θ is the diagonal regularization weight matrix; θ is the physical parameter of the hydraulic structure that needs to be adjusted; θ ₀ is the value in the finite element model The current values of the physical parameters of the hydraulic structure that need to be adjusted; (·) ^T is the transpose of the matrix; is the i-th order frequency residual vector of the hydraulic structure; λ _i (θ) is the i-th order frequency calculated by the finite element model based on the physical parameters of the hydraulic structure that currently need to be adjusted;/> is the measured i-th order frequency of the hydraulic structure;/> is the residual vector of the i-th vibration mode of the hydraulic structure; φ ⁱ (θ) is the i-th overall mode shape calculated by the finite element model based on the physical parameters of the hydraulic structure that currently need to be adjusted; The mode shape of each measuring point of the i-th order calculated for the finite element model based on the physical parameters of the hydraulic structure that currently needs to be adjusted;/> is the measured i-th overall vibration shape of the hydraulic structure;/> is the measured mode shape of each measuring point of the i-th order of the hydraulic structure.

In one embodiment of the present invention, as shown in Figure 2, a certain gravity dam leakage dam includes a dam body and a gate pier. The material parameters of the gravity dam leakage dam are as shown in Table 1. According to the gravity dam leakage dam The natural frequencies calculated with the known parameters are shown in Table 2. Figure 3, Figure 4 and Figure 5 are the schematic diagrams of the first-order vibration shape, the second-order vibration shape and the third-order vibration shape respectively. The measured first three-order natural frequencies are shown in Table 3, and the measured first three-order vibration shapes are shown in Figure 6.

Table 1: Material parameters

Table 2: Natural vibration frequency calculated based on the known parameters of the gravity dam discharge dam

Modal order Natural frequency (Hz) 1 4.30 2 4.31 3 4.35 4 6.37 5 6.38 6 6.41 7 10.79 8 11.08 9 11.09 10 11.11

Table 3: The first three natural vibration frequencies

The first three natural vibration frequencies and vibration shapes are taken for calculation, and a total of eight parameters including the density and dynamic elastic modulus of the four types of concrete C25, C30, C35, and C40 are used as the physical parameters of the hydraulic structure that need to be adjusted, and are obtained through MATLAB. The deterministic dynamic model updates the values of the physical parameters of the hydraulic structure that need to be adjusted corresponding to the minimum value of the objective equation, completing the update of the finite element model, that is, completing the establishment of the digital twin model of the hydraulic structure.

The selection process of some physical parameters of the hydraulic structure that need to be adjusted is shown in Figure 7. The abscissa numbers in the figure correspond to a material parameter, the ordinate is the natural frequency value of the finite element model, and the abscissas correspond from left to right. The material parameters are: density _{C25 ,} elastic modulus _C25 , Poisson's ratio C25, density _C30 , elastic modulus _C30 , Poisson's ratio _C30 , density _C35 , elastic modulus _C35 , Poisson's ratio _C35 , density _C40 , elastic modulus _C40 and Poisson's ratio _C40 . As can be seen from Figure 7, in this embodiment, the elastic modulus _C25 , density _C30 , elastic modulus _C30 , density _C35 and elastic modulus _C35 have a greater impact on the natural frequency of the hydraulic structure. Therefore, the above five material parameters are selected as the parameters that need to be adjusted. physical parameters of the hydraulic structure.

To sum up, the present invention only needs to consider the basic information of the hydraulic structure, and can automatically complete the update of the finite element model based on the basic information and the change process, thereby realizing the establishment of a digital twin model of the hydraulic structure.

Claims (2)

1. The method for establishing the digital twin model of the hydraulic structure is characterized by comprising the following steps of:

s1, constructing a finite element model according to known physical parameters of a hydraulic structure based on finite element software;

s2, acquiring self-vibration frequency and vibration mode information of the hydraulic structure at 1 st order or above in the actual operation process, acquiring the self-vibration frequency and vibration mode information obtained by calculation of the finite element model, and selecting physical parameters of the hydraulic structure to be adjusted;

s3, establishing a deterministic power model updating target equation for physical parameters of the hydraulic structure to be adjusted according to the data obtained in the step S2;

s4, acquiring a value of a physical parameter of the hydraulic structure to be adjusted, which corresponds to the minimum value of the deterministic power model updating target equation, and finishing updating of the finite element model, namely finishing establishment of the hydraulic structure digital twin model;

the specific method for selecting the physical parameters of the hydraulic structure to be adjusted in the step S2 comprises the following substeps:

s2-1, acquiring all material parameters of a hydraulic structure, and increasing one material parameter by 20% each time in a finite element model by adopting a single variable method until the material parameter is increased to 160% of an original value, and acquiring the self-vibration frequency of the finite element model corresponding to the material parameter which is increased each time; the natural frequency of the finite element model is the first 3-6 order natural frequency in the finite element model;

s2-2, acquiring a corresponding self-vibration frequency change rate according to the self-vibration frequency of the finite element model after each increase of each material parameter;

s2-3, sequencing corresponding material parameters according to the change rate of the self-vibration frequency in a mode from large to small, and selecting the first n material parameters as physical parameters of the hydraulic structure to be adjusted;

in the step S3, the deterministic power model updating target equation specifically includes:

f(θ)＝r(θ) ^T Wr(θ)+(θ-θ ₀ ) ^T W _θ (θ-θ ₀ )

wherein f (θ) is the value of the deterministic power model update target equation; r (θ) is the residual vector; r is (r) _f (θ) is a frequency residual vector comprising each order of frequency residual vector; r is (r) _s (θ) is a vibration mode residual vector including eachA residual vector of the order vibration mode; w is a diagonal weight matrix; w (W) _θ Regularizing the weight matrix for the diagonal direction; θ is a physical parameter of the hydraulic structure to be adjusted; θ ₀ The current value of the physical parameter of the hydraulic structure to be adjusted in the finite element model is the current value of the physical parameter of the hydraulic structure to be adjusted; (. Cndot. ^T Is the transpose of the matrix;the i-th order frequency residual vector is the hydraulic structure; lambda (lambda) _i (theta) is the ith order frequency calculated by the finite element model based on the physical parameters of the hydraulic structure which is currently required to be adjusted; />The measured i-th order frequency of the hydraulic structure; />The residual vector is the ith vibration receiving type residual vector of the hydraulic structure; phi (phi) ⁱ (theta) is the i-th order overall vibration mode obtained by calculating the finite element model based on the physical parameters of the hydraulic structure which is required to be adjusted currently; />The method comprises the steps that the vibration mode of each measuring point of an ith order is calculated for a finite element model based on physical parameters of a hydraulic structure which needs to be adjusted currently; />The actual measurement of the ith order overall vibration mode of the hydraulic structure; />The vibration mode of each measuring point of the i th order of the actual measurement of the hydraulic structure is obtained.

2. The method for establishing a digital twin model of a hydraulic structure according to claim 1, wherein the specific method for obtaining the value of the physical parameter of the hydraulic structure to be adjusted corresponding to the minimum value of the deterministic power model update target equation in step S4 is as follows:

and obtaining the value of the physical parameter of the hydraulic structure to be adjusted corresponding to the minimum value of the deterministic power model updating target equation through MATLAB.