Energy storage container earthquake simulation method and system

Abstract

The invention discloses an earthquake simulation method for an energy storage container. The method comprises the following steps: acquiring an initial three-dimensional model of the energy storage container; constructing a corresponding multi-rigid body system; carrying out modal analysis on the multi-rigid-body system by adopting an SRSS method to obtain the sum of rigid modals so as to generate a corresponding time domain-multi-rigid-body system seismic response spectrum; and converting the time domain-multi-rigid-body system seismic response spectrum into a corresponding frequency domain-multi-rigid-body system seismic response spectrum, and solving an equation under the action of seismic acceleration based on the frequency domain-multi-rigid-body system seismic response spectrum to obtain an acceleration response curve of each rigid body. The invention further provides an energy storage container earthquake simulation system. According to the method provided by the invention, the response of the energy storage container under the earthquake action can be quickly and accurately simulated, so that a scientific basis is provided for design, installation and operation of the energy storage container.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of energy storage, and particularly relates to an energy storage container earthquake simulation method and system. BACKGROUND

[0002] With the increasing demand for energy and the widespread use of renewable energy, energy storage technology has developed rapidly. Energy storage containers, as an efficient and convenient energy storage solution, are widely used in power systems, industrial fields and emergency backup power supply scenarios. However, in the event of earthquakes and other natural disasters, energy storage containers may be severely damaged, affecting their normal operation and safety. Therefore, it is of great practical significance to conduct earthquake simulation analysis on energy storage containers to evaluate their response and reliability under earthquake action.

[0003] The main method for seismic design and verification of large containers is through theoretical calculation of finite elements. Currently, there are few studies on such simulation methods, and existing research mainly focuses on linear theoretical calculations of simplified container frame models. However, in actual container applications, many key components such as battery boxes and container supports are not pure linear connection processing methods. The earthquake intensity equivalent evaluation method of key components such as battery racks and the influence of mechanical parameters of battery pack boxes on system stiffness are not considered. In addition, the evaluation method for the nonlinear section of the main frame of the energy storage container is not perfect, which is difficult to meet the needs of actual engineering applications.

[0004] Patent document CN119066949A discloses a power infrastructure resilience evaluation method considering multi-factor coupling influence, including: based on seismic intensity historical data, calculating the response result data corresponding to each preset index type; according to the maximum correlation minimum redundancy algorithm, processing the response result data to determine the key influence factor type and the secondary influence factor type from the preset index type; based on Monte Carlo simulation, creating multiple power infrastructure earthquake simulation events, and according to the simulation results, extracting first simulation data corresponding to the key influence factor type and second simulation data corresponding to the secondary influence factor type; according to the first simulation data and the second simulation data, correcting the response result data to obtain corrected result data; inputting the corrected result data into a preset evaluation result calculation formula to obtain the power infrastructure resilience evaluation result.

[0005] Patent document CN112560177A discloses an improved anti-seismic characteristic simulation calculation method for response synthesis of reaction spectrum excitation, including reaction spectrum envelope and interpolation calculation of corresponding damping coefficients under different seismic load; three-dimensional solid geometric model establishment; node group and contact surface group setting; load combination and working condition; boundary constraint and load application; mesh division and independence test; simulation calculation and response synthesis; evaluation criteria and result evaluation; connection bolt or weld joint checking. SUMMARY

[0006] The application aims to provide a method and system for simulating the response of an energy storage container under earthquake, which can quickly and accurately simulate the response of an energy storage container under earthquake, thereby providing a scientific basis for the design, installation and operation of the energy storage container.

[0007] In order to achieve the first object of the application, the following technical solution is provided: a method for simulating the response of an energy storage container under earthquake, comprising the following steps: obtaining an initial three-dimensional model of the energy storage container, the initial three-dimensional model comprising a container structure, energy storage devices and connecting components, the container structure comprising a base support, support columns erected on the base support and crossbars connecting adjacent support columns and serving as the bottom support of the energy storage devices; regarding the connection of the base support, the support columns and the crossbars as welding, regarding the bolt connection between one side of the energy storage devices and the container structure as rigid connection, and regarding the remaining contact surface between the energy storage devices and the container structure as weak rigid connection, to construct a corresponding multi-rigid-body system; performing modal analysis and the sum of rigid modes on the multi-rigid-body system by using the SRSS method, to generate a corresponding time-domain multi-rigid-body system earthquake response spectrum; converting the time-domain multi-rigid-body system earthquake response spectrum to a corresponding frequency-domain multi-rigid-body system earthquake response spectrum, and solving the equation under the action of earthquake acceleration based on the frequency-domain multi-rigid-body system earthquake response spectrum, to obtain the acceleration response curve of each rigid body.

[0008] The application divides the connection mode between the batteries and the beam body in the energy storage container into rigid connection and weak rigid connection, so that the equivalent stiffness is close to the actual value in the subsequent simulation process, and the accuracy of the final simulation result is further improved.

[0009] Specifically, the multi-rigid-body system comprises the mass, the moment of inertia and the connection relationship of the container structure and each energy storage device.

[0010] Specifically, the moment of inertia of the energy storage device is obtained by equivalent calculation based on the straight-line distance between the center of mass of the energy storage device and the center of mass of the container structure.

[0011] Specifically, the moment of inertia of the energy storage device is represented as follows: ; wherein, wi represents the weight of the i-th energy storage device, di represents the straight-line distance from the center of mass of the i-th energy storage device to the center of mass of the container structure.

[0012] Specifically, the expression of the equation under the action of earthquake acceleration is as follows: ; After moving the formula: ; Wherein, represents the seismic action value, represents the equivalent static force, represents the absolute acceleration inertial force, represents the damping, represents the ground acceleration, represents the structure relative acceleration.

[0013] Specifically, the SRSS method uses horizontal seismic components and vertical seismic components to perform modal analysis on the multi-rigid body system.

[0014] Specifically, the horizontal seismic component and the vertical seismic component are combined using the 100 / 40 / 40 rule, and the seismic component is combined using the 100 / 40 / 40 rule. One of the three directions is taken as the main earthquake direction, and three kinds of working condition earthquake analysis are calculated respectively. The results are more in line with the actual application working condition.

[0015] Specifically, the expression of the sum of the rigid modes is as follows: ; Wherein, represents the physical quantity caused by the excitation of the I direction, R pI represents periodic part, R rI represents rigid part.

[0016] Specifically, the physical quantity includes displacement, velocity, acceleration, strain component, stress component, effective stress or beam cross section force.

[0017] In order to realize the second object of the application, a energy storage container earthquake simulation system is provided for executing the steps of the energy storage container earthquake simulation method as described above, comprising: An input unit is used to input the initial three-dimensional model of the energy storage container; An equivalent change unit is used to equivalently convert the input initial three-dimensional model into a multi-rigid body system; A simulation unit performs simulation analysis according to the preset seismic action value and the converted multi-rigid body system to output the corresponding frequency domain-multi-rigid body system seismic response spectrum; An output unit outputs the acceleration response curve of each rigid body according to the generated frequency domain-multi-rigid body system seismic response spectrum.

[0018] Compared with the prior art, the present application has the following advantages: The connection between the battery and the beam is subdivided, i.e. end bolt connection, tail nonlinear connection, and linear analysis based on modal response spectrum, thereby realizing high-quality equivalent modeling and improving the accuracy of the final simulation result.

[0019] In addition, rigid connection is adopted, and mass point and moment of inertia properties are assigned instead of energy storage devices, thereby reducing the grid and increasing the calculation speed. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A schematic diagram of a seismic simulation method of an energy storage container is provided for the present embodiment; Figure 2 A schematic diagram of a box structure is provided for the present embodiment; Figure 3 A partial schematic diagram of a box structure is provided for the present embodiment; Figure 4 A schematic diagram of the center of mass of the energy storage device at the corresponding position is provided for the present embodiment; Figure 5 A schematic diagram of the force direction in the simulation process is provided for the present embodiment; In the figure, 1 is the tail of the support, 2 is the crossbar, 3 is the end of the support, 4 is the weak rigid connection, 5 is the rigid connection, 6 is the base support, and 7 is the support column. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0022] As Figure 1 shown, a seismic simulation method of an energy storage container is provided for the present embodiment, and the steps are as follows: An initial three-dimensional model of the energy storage container is obtained, which includes a box structure, an energy storage device and a connecting component.

[0023] As Figure 2 and Figure 3As shown, the box structure includes a base support 6, support columns 7 erected on the base support 6, and crossbars 2 connecting adjacent support columns 7 and used as bottom support of the energy storage device.

[0024] For the initial three-dimensional model, the base support, the support column, and the connection of the crossbar are regarded as welding, the bolt connection between one side of the energy storage device and the box structure is regarded as rigid connection, and the remaining contact surface of the energy storage device and the box structure is regarded as weak rigid connection, to construct a corresponding multi-rigid body system.

[0025] More specifically, the front end of the battery pack is fixed by bolts and fixed with the bracket end 3, the tail is not fixed between the bracket tail 1, and the battery and the crossbar are bolted, so as shown in the modeling of the model, the battery pack end fixing bracket is retained and the bolt is replaced by an rbe2 rigid connection 5, and the tail of the battery pack is equivalent to an rbe3 weak rigid connection 4. Such modeling method does not increase the rigidity of the system, and the calculation result is more accurate. Figure 4

[0026] In addition, the inertia moment of the battery centroid is defined as follows: According to the momentum theorem of theoretical mechanics: And the momentum theorem: It is known that the size of the mass inertia moment represents the ability of the object to rotate, which has an impact on the system stiffness, so the equivalent calculation needs to be considered; At the same time, from the perspective of multi-body dynamics, when calculating the rotational inertia of the system, the parallel axis principle is needed to convert the rotational inertia of the battery centroid in the battery centroid to the centroid of the system, that is , m is the mass of one of the battery centroids, r is the distance from the battery centroid to the centroid of the system, and J is the rotational inertia of the Pack box itself centroid. Obviously, the value of J affects the size of the rotational inertia of the system, and the rotational inertia affects the system modal, and then affects the response of the system to vibration.

[0027] The calculation process is as follows: The mass inertia moment, also known as the moment of inertia, has the same important position as the mass, which is the second moment of mass with respect to distance in space, and has a direct impact on the system stiffness For a discrete particle system, it can be expressed as: ; Wherein, represents the weight of the i-th energy storage device, represents the linear distance from the centroid of the i-th energy storage device to the centroid of the box structure, and for a continuous body, it can be expressed as: .

[0028] ​Meanwhile, since earthquakes are low-frequency responses with a resonant frequency of only about 8Hz, for large energy storage systems with high tonnage, the 1-2Hz stiffness increase of the support structure can greatly help with earthquake intensity. This is because the equivalent modeling at the details directly affects the accuracy of the simulation results and is crucial for the lightweight design of the system.

[0029] In this embodiment, the SRSS method is used to perform modal analysis and summation of rigid modes on the multi-rigid-body system to generate the corresponding time-domain multi-rigid-body system seismic response spectrum. In practical operation, hierarchical modeling is employed, and the boundary conditions for its calculation are based on… Figure 5 The boundary acceleration conditions of the support structure extracted from the seismic modeling calculation are used as the input conditions for this hierarchical modeling. The acceleration loads at key locations in the seismic dynamics analysis of the system are extracted, and the equivalent anisotropic acceleration loads are converted into static analysis. Then, nonlinear analysis can be used to accurately model local key areas and accurately evaluate the strength of key components such as the support structure. In addition, in the calculation of low-cycle fatigue life, hot spot stress is often plastically corrected by the Neuber assumption and transformed into pseudo-hot spot stress. Then, the fatigue life is calculated using the low-cycle fatigue life design curve based on the pseudo-hot spot stress.

[0030] The number of natural modes is selected such that the cumulative participating mass is at least 90% of the total seismic mass; the periodic and rigid responses of all modes are summed separately and then combined as follows: ; in, This represents the physical quantity caused by excitation in the I direction. R pI express The periodic part, R rI express The rigid part.

[0031] Modal combination was performed using the SRSS method, which is suitable for container systems where the modal spacing is not tight. The SRSS method does not include any interactions between modes, i.e.: .

[0032] The seismic response spectrum of the time-domain multi-rigid-body system is converted to the corresponding seismic response spectrum of the frequency-domain multi-rigid-body system, and the equations under seismic acceleration are solved based on the seismic response spectrum of the frequency-domain multi-rigid-body system to obtain the acceleration response curves of each rigid body.

[0033] More specifically, through visual observation of the signal, the main frequency components are in the range of 3~8Hz and the duration is about 30s. Therefore, these conditions cannot be regarded as steady state. The seismic spectrum in the time domain is converted to the response spectrum curve in the frequency domain to calculate the seismic response spectrum analysis.

[0034] The equation under the single degree of freedom seismic acceleration action is: ; After moving the formula: ; Wherein, represents the seismic action value, represents the equivalent static force, represents the absolute acceleration inertial force, represents the damping, represents the ground acceleration, represents the structure relative acceleration.

[0035] Based on the results of the previous modal analysis, input the acceleration response spectrum at the corresponding frequency and the corresponding damping for seismic response spectrum analysis (two horizontal and vertical seismic components are combined using the 100 / 40 / 40 rule. As the damping value, it uses a damping of 2%.) Collect the acceleration response curve on each layer pack / key energy storage device support, and finally analyze the overall structure response of the energy storage container according to the response of each rigid body, including box deformation, connecting component stress, etc.; Synchronous key components such as battery centroid detailed equivalent modeling, input equivalent maximum acceleration response as input condition, consider contact nonlinearity / material nonlinearity and equivalent modeling influence of limiting structure, equivalent conversion to statics calculation to evaluate.

[0036] In the usual seismic response spectrum analysis calculation, due to the limitation of modal linear calculation, the linear elastic calculation result of the response output may be far beyond the actual stress value of the structure, resulting in too conservative evaluation result. Therefore, based on the low cycle fatigue life calculation process, Neuber criterion is introduced to evaluate the actual local stress and strain of the structure, and the Neuber criterion is as follows: .

[0037] The embodiment also provides an energy storage container earthquake simulation system for executing the steps of the energy storage container earthquake simulation method provided by the above-mentioned embodiment, comprising: An input unit for inputting an initial three-dimensional model of an energy storage container; An equivalent change unit for equivalently converting the input initial three-dimensional model into a multi-rigid body system; A simulation unit for performing simulation analysis according to a preset seismic action value and the converted multi-rigid body system to output a corresponding frequency domain-multi-rigid body system seismic response spectrum; An output unit for outputting the acceleration response curve of each rigid body according to the generated frequency domain-multi-rigid body system seismic response spectrum.

[0038] In order to better illustrate the technical effect of the method provided in the present application, the following calculation process takes the elastic stress result of 690.1 MPa as an example.

[0039] The elastic stress of the centroid position is calculated: .

[0040] The digital hyperbolic formula is introduced: .

[0041] The actual stress and strain of the centroid position are calculated: ; .

[0042] The above results are brought into the stress-strain curve of the material, and the intersection of the two curves is the actual stress-strain of the centroid position, so as to obtain the actual stress and strain of the centroid position: ; .

[0043] In addition, in the above calculation process, because , then to meet the requirements of seismic strength design.

[0044] In addition, the terms "upper", "lower", "inner", "outer", "front", "rear" are only used for description purposes, and cannot be understood as indicating or implying relative importance. Unless otherwise specified, the relative steps, numerical expressions and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0045] Of course, the above only describes specific embodiments of the present application, and does not limit the scope of the present application. Any equivalent changes or modifications made in accordance with the structure, features and principles described in the patent application scope of the present application shall be included in the patent application scope of the present application.

[0046] Finally, it should be noted that the above-described embodiments are only specific implementations of the present application, which are used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can make modifications or easily think of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed by the present application, or make equivalent substitutions for some technical features; and these modifications, changes or substitutions do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A seismic simulation method for energy storage containers, characterized in that, The method comprises the following steps: An initial three-dimensional model of the energy storage container is obtained, the initial three-dimensional model comprising a box structure, energy storage devices, and connecting components, the box structure comprising a base support, support columns erected on the base support, and crossbars connecting adjacent support columns and used as bottom supports for the energy storage devices; The base support, the support columns, and the connections of the crossbars are regarded as welded connections, the bolt connections between one side of the energy storage devices and the box structure are regarded as rigid connections, and the remaining contact surfaces between the energy storage devices and the box structure are regarded as weak rigid connections, based on the initial three-dimensional model, to construct a corresponding multi-rigid-body system; SRSS is used to perform modal analysis on the multi-rigid-body system and the sum of rigid modes, to generate a corresponding time-domain multi-rigid-body system seismic response spectrum; The time-domain multi-rigid-body system seismic response spectrum is converted into a corresponding frequency-domain multi-rigid-body system seismic response spectrum, and the equation under seismic acceleration is solved based on the frequency-domain multi-rigid-body system seismic response spectrum, to obtain the acceleration response curves of the rigid bodies.

2. The energy storage container seismic simulation method of claim 1, wherein, The multi-rigid-body system comprises the mass, the moment of inertia, and the connection relationship of the box structure and the energy storage devices.

3. The energy storage container seismic simulation method of claim 2, wherein, The moment of inertia of the energy storage devices is obtained by equivalent calculation of the linear distance between the center of mass of the energy storage devices and the center of mass of the box structure.

4. The energy storage container seismic simulation method of claim 3, wherein, The moment of inertia of the energy storage devices is represented as follows: ； wherein, represents the weight of the i-th energy storage device, represents the straight-line distance from the center of mass of the i-th energy storage device to the center of mass of the box structure.

5. The energy storage container seismic simulation method of claim 1, wherein, The expression of the equation under seismic acceleration is as follows: ； After moving the formula: ； wherein, denotes the seismic action value, denotes the equivalent static force, denotes the absolute acceleration inertial force, denotes the damping, denotes the ground acceleration, denotes the structural relative acceleration.

6. The energy storage container seismic simulation method of claim 1, wherein, The SRSS method uses horizontal seismic components and vertical seismic components to perform modal analysis on the multi-rigid-body system.

7. The energy storage container seismic simulation method of claim 6, wherein, The horizontal seismic components and the vertical seismic components are combined using the 100 / 40 / 40 rule.

8. The energy storage container seismic simulation method of claim 1, wherein, The expression of the sum of rigid modes is as follows: ； wherein represents a physical quantity caused by the excitation in the I direction, R pI represents a periodic part of R rI represents a rigid part of 9. The energy storage container seismic simulation method of claim 8, wherein, The physical quantities include displacement, velocity, acceleration, strain components, stress components, effective stress, or beam cross-section force.

10. An energy storage container seismic simulation system, comprising: A device for performing the steps of the energy storage container seismic simulation method according to any one of claims 1-9, comprising: An input unit configured to input an initial three-dimensional model of the energy storage container; An equivalent change unit configured to equivalently convert the input initial three-dimensional model into a multi-rigid-body system; A simulation unit configured to perform simulation analysis according to a predetermined seismic action value and the converted multi-rigid-body system, to output a corresponding frequency-domain multi-rigid-body system seismic response spectrum; An output unit configured to output the acceleration response curves of the rigid bodies based on the generated frequency-domain multi-rigid-body system seismic response spectrum.

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