Method for simulating and analyzing expansion condition of corrugated sheet of corrugated oil tank

Abstract

The invention belongs to the technical field of corrugated oil tank corrugated sheet analysis, and particularly relates to a corrugated oil tank corrugated sheet expansion condition simulation analysis method, which comprises the following steps of: firstly, constructing a half simulation model of a corrugated sheet based on a symmetrical structure of the corrugated sheet of a corrugated oil tank; secondly, welding spots of the half simulation model are replaced with bosses, and symmetric boundary conditions are applied to symmetric planes; then, material parameters are given to the half simulation model, the face where a welding spot is located is set to be a fixed geometry, all degrees of freedom are limited, and the welding spot and a corrugated sheet are set to be in binding contact; and finally, applying a load to the half simulation model, executing static linear analysis, generating an analysis result, and judging whether each index in the analysis result meets a preset index requirement or not, if not, optimizing the simulation model parameters, repeating the steps, and performing static linear analysis again until the output meets the preset index requirement. The problem that in the prior art, a traditional corrugated sheet deformation analysis method is high in cost can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of corrugated sheet analysis of a corrugated oil tank, and in particular relates to a method for simulating and analyzing the expansion of a corrugated sheet of a corrugated oil tank. Background Art

[0002] The expansion of the corrugated sheet of the corrugated oil tank is crucial to the performance and safe operation of the transformer as it is a key component of the transformer. During the operation of the transformer, the increase in oil temperature will increase the oil volume, which requires the corrugated sheet to have a certain expansion space; however, excessive deformation of the corrugated sheet will have an adverse effect on the heat dissipation performance, thereby affecting the overall performance of the transformer. Therefore, accurately grasping the expansion of the corrugated sheet and effectively controlling its deformation is of great significance for optimizing the design of the corrugated oil tank and ensuring the stable operation of the transformer.

[0003] In the current corrugated fuel tank manufacturing field, the processing of corrugated sheets involves key processes such as reinforcement and resistance welding, which play a key role in controlling the deformation of the corrugated sheets. However, in the traditional production process, there are obvious deficiencies in the evaluation of the impact of the size and position of the reinforcement ribs and the position and number of the resistance welding points on the deformation of the corrugated sheets. Usually, it is necessary to complete the production of the product first, and then conduct strength sealing experiments to obtain relevant measurement data to determine the impact of various factors on the deformation of the corrugated sheets. This method not only consumes a lot of time, but also has high verification costs, which seriously restricts the improvement of production efficiency and the control of production costs.

[0004] Traditional professional analysis software has significant advantages in analyzing the expansion and deformation of corrugated sheets. With its powerful functions, this type of software can conduct professional and accurate analysis of the deformation of corrugated sheets. They use complex algorithms and models, take into account multiple factors, and obtain highly accurate analysis results.

[0005] Although traditional professional analysis software performs well in analysis accuracy, it has many limitations in practical applications. On the one hand, the analysis conditions of these software are extremely strict, and they have high requirements for hardware equipment and operating environment, which increases the difficulty and cost of use; on the other hand, the learning cost of the software is high, and operators need to invest a lot of time and energy to learn and master complex operating procedures and professional knowledge. For the analysis of the deformation of corrugated sheets, actual production does not require such high-precision data. It is more hoped that a feasible solution can be obtained through software simulation, and basic theoretical data can be provided to guide subsequent production practices. Therefore, these defects of traditional professional analysis software have greatly limited its practical application in the analysis of the deformation of corrugated sheets, and it is difficult to meet the needs of production companies for high efficiency and low cost. Summary of the invention

[0006] The technical problem solved by the present invention is to provide a method for simulating and analyzing the expansion of corrugated sheets of a corrugated fuel tank, so as to solve the problem of high cost in the traditional corrugated sheet deformation analysis method in the prior art.

[0007] The basic solution provided by the present invention: A method for simulating and analyzing the expansion of corrugated sheets of a corrugated fuel tank, including:

[0008] S1: Based on the symmetric structure of the corrugated sheet of the corrugated fuel tank, construct a half simulation model of the corrugated sheet;

[0009] S2: Replace the solder joints of the half simulation model of the corrugated sheet with bosses, apply symmetric boundary conditions on the symmetric plane, and restrict the normal displacement, allowing free expansion in the plane;

[0010] S3: Assign material parameters to the half simulation model of the corrugated sheet, set the surface where the solder joints are located as a fixed geometric body, restrict all degrees of freedom, and set a bonded contact between the solder joints and the corrugated sheet;

[0011] S4: Apply a load to the half simulation model of the corrugated sheet that has gone through S2 - S3, perform a static linear analysis, generate an analysis result, and determine whether each index in the analysis result meets the preset index requirements. If not, optimize the simulation model parameters, repeat S1 - S3, and perform a static linear analysis again until an output that meets the preset index requirements is obtained.

[0012] Further, the S1 includes:

[0013] S1 - 1: Based on the symmetric structure of the corrugated sheet of the corrugated fuel tank, identify the symmetric features of the corrugated sheet;

[0014] S1 - 2: Construct a corrugated sheet simulation model, generate a symmetric reference plane based on the identified symmetric features of the corrugated sheet, and divide the corrugated sheet simulation model into a half simulation model of the corrugated sheet according to the symmetric reference plane;

[0015] S1 - 3: Perform symmetry verification and lightweight processing on the divided half simulation model of the corrugated sheet to obtain a half simulation model that meets the actual performance of the corrugated sheet.

[0016] Further, the S2 includes:

[0017] S2 - 1: Obtain the actual solder joint positions and dimensions of the corrugated sheet, and create cylindrical bosses with a height of 0.01 mm at the corresponding positions on the half simulation model of the corrugated sheet based on the actual solder joint positions and dimensions;

[0018] S2 - 2: Apply symmetric boundary conditions based on the symmetric reference plane of the half simulation model of the corrugated sheet, and the symmetric boundary conditions are: Restrict the normal displacement U z= 0, allowing free expansion in the plane U x , U y Free.

[0019] Furthermore, the S3 includes:

[0020] S3-1: Assign material parameters to half of the simulation model of the corrugated sheet, and the material parameters include elastic modulus, Poisson's ratio, and density;

[0021] S3-2: Set the surface where the solder joint is located as a fixed geometric body, and constrain all degrees of freedom, where U x = U y = U z = 0;

[0022] S3-3: Set the bottom surface of the cylindrical boss where the solder joint is located and the surface of the corrugated sheet as the contact surface, and bind and contact the contact surface where the solder joint is located and the contact surface where the corrugated sheet is located.

[0023] Furthermore, the S4 includes:

[0024] S4-1: Uniformly apply a normal pressure to the contact oil side of half of the simulation model of the corrugated sheet, and the direction is perpendicular to the surface;

[0025] S4-2: Locally refine the mesh in the solder joint area of half of the simulation model of the corrugated sheet. The main body of the simulation model uses a gradient mesh process. Perform a static linear analysis on half of the simulation model of the corrugated sheet, enable the sparse matrix solver for iteration, and obtain the analysis results of key indicators;

[0026] S4-3: If the analysis results of the key indicators do not meet the preset requirements, then adjust the model parameters of half of the simulation model of the corrugated sheet, and repeat S1-S3 until the analysis results of the key indicators meet the preset requirements.

[0027] Furthermore, the normal pressure expression in the S4-1 is:

[0028]

[0029] where P represents the equivalent static pressure, ΔV represents the change in oil volume, V represents the initial oil volume, and K oil represents the bulk modulus of elasticity of the oil.

[0030] The principle and advantages of the present invention are as follows: In this application, by utilizing the symmetric structure of the corrugated sheet of the corrugated fuel tank, a half simulation model is constructed to simplify the calculation. The model construction is completed by identifying the symmetric features, creating a symmetric datum plane, and dividing the model. The solder joints are replaced by bosses, and symmetric boundary conditions are applied to restrict the normal displacement while allowing free expansion in the plane. The material parameters are assigned to the model, the plane where the solder joints are located is fixed, and the solder joints and the corrugated sheet are set as bonded contacts. A normal pressure calculated based on factors such as the change in oil volume is applied to the side in contact with the oil, the local mesh of the solder joint area is refined, and the main body uses a gradient mesh for static linear analysis. The sparse matrix solver is enabled to iterate to obtain the analysis results of key indicators. If the results do not meet the preset requirements, the model parameters are adjusted and the above process is repeated.

[0031] The advantages are as follows: The method in this application can effectively evaluate the performance of the corrugated sheet by accurately simulating the expansion of the corrugated sheet under oil pressure. By adopting a symmetric model and reasonable boundary condition settings, while ensuring the calculation accuracy, the calculation amount is greatly reduced, the calculation efficiency is improved, and the technical cost is reduced. The accurate simulation of the solder joints and the mesh processing method make the analysis results more in line with the actual situation, providing a reliable basis for the design optimization of the corrugated fuel tank, helping to improve the safety and stability of the corrugated fuel tank in actual use, and reducing the failure risk caused by unreasonable design. Brief Description of the Drawings

[0032] Figure 1 is a flowchart of an embodiment of the present invention;

[0033] Figure 2 is a schematic structural diagram of a half simulation model of the corrugated sheet in an embodiment of the present invention;

[0034] Figure 3 is a schematic diagram of the solder joints of the half simulation model in an embodiment of the present invention;

[0035] Figure 4 is a schematic diagram of the maximum deformation amount in the analysis results of key indicators in an embodiment of the present invention;

[0036] Figure 5 is an example diagram of the maximum stress value in the analysis results of key indicators in an embodiment of the present invention. Detailed Embodiment

[0037] The following is a further detailed description through specific embodiments:

[0038] The embodiment is basically as shown in the attached Figure 1 figures: A method for simulating and analyzing the expansion of a corrugated sheet of a corrugated fuel tank includes:

[0039] S1: Based on the symmetric structure of the corrugated sheet of the corrugated fuel tank, construct a half simulation model of the corrugated sheet; wherein, S1 includes:

[0040] S1-1: Identify the symmetry features of the corrugated sheet based on the symmetric structure of the corrugated sheet of the corrugated tank.

[0041] S1-2: Construct a simulation model of the corrugated sheet, generate a symmetric reference plane based on the identified symmetry features of the corrugated sheet, and divide the simulation model of the corrugated sheet into a half-simulation model of the corrugated sheet according to the symmetric reference plane.

[0042] S1-3: Perform symmetry verification and lightweight processing on the half-simulation model of the corrugated sheet after division to obtain a half-simulation model that meets the actual performance of the corrugated sheet.

[0043] In this embodiment, for the corrugated sheet of the corrugated tank, first construct a simulation model of the corrugated sheet, identify its symmetric structure, such as mirror symmetry or periodic symmetric structure, select a symmetric plane, such as the mid-plane of the corrugation peak / valley, as the symmetric reference plane, and divide the simulation model of the corrugated sheet with the symmetric reference plane to obtain a half-simulation model of the corrugated sheet, as Figure 2 shown. In this application, the force conditions on each surface of the corrugated sheet are the same under the expansion condition, and the force conditions inside the corrugated sheet are also uniformly symmetric. Therefore, when performing simulation analysis, designing the model as half of a single sheet can save a lot of time in simulation analysis.

[0044] After the half-simulation model of the corrugated sheet is constructed, it is inspected and optimized. Among them, symmetry verification is first performed. Specifically, check that the flatness error of the cutting surface ≤ 0.1 mm, confirm that the symmetry deviation of the solder joint position < the design tolerance, and verify the periodic characteristics of the corrugation pitch; then perform lightweight processing on the model, including removing non-loaded features, such as process holes, chamfers, etc., simplifying complex curved surfaces into resolvable geometric surfaces, and maintaining the key dimensional tolerance of ±0.5 mm.

[0045] S2: Replace the solder joints of the half-simulation model of the corrugated sheet with bosses, apply symmetric boundary conditions on the symmetric plane, and restrict the normal displacement, allowing free expansion in the plane; where S2 includes:

[0046] S2-1: Obtain the actual solder joint positions and dimensions of the corrugated sheet, and create cylindrical bosses with a height of 0.01 mm at the corresponding positions of the half-simulation model of the corrugated sheet based on the actual solder joint positions and dimensions.

[0047] S2-2: Apply symmetric boundary conditions based on the symmetric reference plane of the half-simulation model of the corrugated sheet, and the symmetric boundary conditions are: restrict the normal displacement U z = 0, allowing free expansion in the plane U x 、U y free.

[0048] In this embodiment, for the modeling of the solder joints on the half simulation model of the corrugated sheet, according to the actual positions and sizes of the solder joints, such as Figure 3 shown, for example, for a solder joint with a diameter of 2 mm, a cylindrical boss with a height of 0.01 mm is created on the surface of the corrugated sheet, and the number and positions of the cylindrical bosses are the same as those of the actual solder joints.

[0049] Next, apply symmetric boundary conditions to the symmetric reference plane of the half simulation model of the corrugated sheet, including restricting the normal displacement U z = 0, and allowing free expansion in the plane U x 、U y to be free.

[0050] S3: Assign material parameters to the half simulation model of the corrugated sheet, set the surface where the solder joints are located as a fixed geometric body, restrict all degrees of freedom, and set the contact between the solder joints and the corrugated sheet as a bonded contact; where S3 includes:

[0051] S3-1: Assign material parameters to the half simulation model of the corrugated sheet, and the material parameters include elastic modulus, Poisson's ratio, and density;

[0052] S3-2: Set the surface where the solder joints are located as a fixed geometric body, and constrain all degrees of freedom, where U x = U y = U z = 0;

[0053] S3-3: Set the bottom surface of the cylindrical boss where the solder joint is located and the surface of the corrugated sheet as the contact surface, and perform a bonded contact between the contact surface where the solder joint is located and the contact surface where the corrugated sheet is located.

[0054] In this embodiment, the material parameters assigned to the half simulation model of the corrugated sheet are set according to the material of the corrugated sheet. For example, for a corrugated sheet made of SUS304 stainless steel, its material parameters are: elastic modulus E = 200 GPa, Poisson's ratio ν = 0.3, density ρ = 7850 kg / m 3 ; Subsequently, select all the surfaces where the solder joint cylindrical bosses are located, set them as fixed geometric bodies, and constrain all degrees of freedom Y x = U y = Y z = 0, and simulate the rigid fixation of the welding area. Finally, define the contact relationship between the solder joint and the corrugated sheet as a bonded contact, and the contact surfaces are the bottom surface of the cylindrical boss and the surface of the corrugated sheet to ensure complete bonding of the contact area.

[0055] S4: Apply a load to the half simulation model of the corrugated sheet that has gone through S2 - S3, perform a static linear analysis, generate the analysis results, and determine whether the indicators in the analysis results meet the preset indicator requirements. If not, optimize the simulation model parameters, repeat S1 - S3, and conduct the static linear analysis again until the output meets the preset indicator requirements. Among them, S4 includes:

[0056] S4 - 1: Uniformly apply a normal pressure to the oil - contacting side of the half simulation model of the corrugated sheet, with the direction perpendicular to the surface.

[0057] S4 - 2: Locally refine the mesh in the solder joint area of the half simulation model of the corrugated sheet. The main body of the simulation model adopts a gradually changing mesh. Conduct a static linear analysis on the half simulation model of the corrugated sheet, enable the sparse matrix solver for iteration, and obtain the analysis results of the key indicators.

[0058] S4 - 3: If the analysis results of the key indicators do not meet the preset requirements, adjust the model parameters of the half simulation model of the corrugated sheet, repeat S1 - S3 until the analysis results of the key indicators meet the preset requirements.

[0059] In this embodiment, simulate the oil pressure expansion effect on the half simulation model of the corrugated sheet with the modeling and parameter settings completed to verify whether the deformation and stress meet the standards. Specifically, first calculate the equivalent static pressure, and the calculation formula is:

[0060]

[0061] where P represents the equivalent static pressure, ΔV represents the change in oil volume, V represents the initial oil volume, and K oil represents the bulk modulus of elasticity of the oil.

[0062] Then, uniformly apply a pressure on the inner surface of the corrugated sheet, that is, the oil - contacting side, with the direction perpendicular to the surface, and then perform a static linear analysis. Specifically, first locally refine the mesh in the solder joint area of the half simulation model of the corrugated sheet so that the element size ≤ 0.5 mm. Then, the main body of the corrugated sheet adopts a gradually changing mesh, with the wave peak / wave valley ≤ 2 mm and the gentle area ≤ 3 mm. Then select the static linear analysis, enable the coefficient matrix solver, set the iteration tolerance to 0.1%, and enable the large displacement effect to obtain the analysis results of the key indicators. In this application, the key indicators include the maximum equivalent stress and the maximum normal displacement. As Figure 4 and Figure 5 shown, among them, the preset requirement for the maximum equivalent stress is that it needs to be less than the material yield strength. Taking SUS304 stainless steel as an example, it needs to be less than 205 Mpa. The preset requirement for the maximum normal displacement is set according to the corrugated sheet material. Taking SUS304 stainless steel as an example, the allowable value ≤ 1.5 mm.

[0063] For the results that do not meet the preset requirement indicators, when the maximum equivalent stress exceeds the standard, increase the number of solder joints, adjust the solder joint spacing, or increase the stiffening height, and vice versa; when the maximum normal displacement exceeds the standard, increase the thickness of the corrugated sheet or optimize the geometry of the wave crest / trough, and vice versa; after optimizing the parameters, perform the above steps again to effectively obtain the parameters of the corrugated sheet that meet the preset requirements.

[0064] The above are only embodiments of the present invention. Specific structures and common knowledge such as characteristics that are well known in the art are not described in detail herein. Those of ordinary skill in the art know all the common general technical knowledge in the technical field to which the invention belongs before the filing date or the priority date, can know all the prior art in this field, and have the ability to apply conventional experimental means before this date. Those of ordinary skill in the art can, under the inspiration given in this application, combine their own abilities to improve and implement this solution. Some typical well-known structures or well-known methods should not become obstacles for those of ordinary skill in the art to implement this application. It should be noted that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, and these should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicality of the patent. The protection scope required by this application should be based on the content of its claims, and the specific implementation manners and the like recorded in the specification can be used to explain the content of the claims.

Claims

1. A method for simulating and analyzing the expansion of a corrugated sheet of a corrugated fuel tank, characterized in that: include: S1: Based on the symmetrical structure of the corrugated sheet of the corrugated oil tank, a simulation model of one-half of the corrugated sheet is constructed; S2: The weld points of the half simulation model of the corrugated sheet are replaced by bosses, symmetric boundary conditions are applied on the symmetric plane, and the normal displacement is restricted, allowing free expansion in the plane; S3: Assign material parameters to the half simulation model of the corrugated sheet, set the surface where the welding point is located as a fixed geometry, restrict all degrees of freedom, and set the welding point and the corrugated sheet to be in binding contact; S4: Apply load to the half simulation model of the corrugated sheet after S2-S3, perform static linear analysis, generate analysis results, and determine whether the various indicators in the analysis results meet the preset indicator requirements. If not, optimize the simulation model parameters, repeat S1-S3, and perform static linear analysis again until the output meets the preset indicator requirements.

2. The method for simulating and analyzing the expansion of a corrugated sheet of a corrugated oil tank according to claim 1, characterized in that: The S1 includes: S1-1: Based on the symmetrical structure of the corrugated sheet of the corrugated fuel tank, identify the symmetrical features of the corrugated sheet; S1-2: constructing a corrugated sheet simulation model, generating a symmetry reference plane based on the identified symmetry features of the corrugated sheet, and dividing the corrugated sheet simulation model into half simulation models of the corrugated sheet according to the symmetry reference plane; S1-3: The symmetry of the split half simulation model of the corrugated sheet is verified and lightweighted to obtain a half simulation model that meets the actual performance of the corrugated sheet.

3. The method for simulating and analyzing the expansion of a corrugated sheet of a corrugated oil tank according to claim 2, characterized in that: The S2 includes: S2-1: Obtain the actual welding point position and size of the corrugated sheet, and create a cylindrical boss with a height of 0.01 mm at the corresponding position of the half simulation model of the corrugated sheet based on the actual welding point position and size; S2-2: Apply symmetric boundary conditions based on the symmetric reference plane of the half simulation model of the corrugated sheet, and the symmetric boundary conditions are: limit the normal displacement U z = 0, allowing free expansion in the plane U x , U y free.

4. The method for simulating and analyzing the expansion of a corrugated sheet of a corrugated oil tank according to claim 3, characterized in that: The S3 includes: S3-1: assigning material parameters to the half simulation model of the corrugated sheet, wherein the material parameters include elastic modulus, Poisson's ratio and density; S3-2: Set the surface where the weld point is located as a fixed geometry and constrain all degrees of freedom, where U x =U y =U z =0; S3-3: The bottom surface of the cylindrical boss where the welding point is located and the surface of the corrugated sheet are set as contact surfaces, and the contact surface where the welding point is located and the contact surface where the corrugated sheet is located are bound and contacted.

5. The method for simulating and analyzing the expansion of a corrugated sheet of a corrugated oil tank according to claim 4, characterized in that: The S4 includes: S4-1: Apply normal pressure uniformly to the oil contact side of the half simulation model of the corrugated sheet, in a direction perpendicular to the surface; S4-2: Perform local mesh encryption on the weld area in the half simulation model of the corrugated sheet, use gradient mesh processing on the main body of the simulation model, perform static linear analysis on the half simulation model of the corrugated sheet, enable the sparse matrix solver for iteration, and obtain the key indicator analysis results; S4-3: If the key indicator analysis result does not meet the preset requirements, adjust the model parameters of the half simulation model of the corrugated sheet, and repeat S1-S3 until the key indicator analysis result meets the preset requirements.

6. The method for simulating and analyzing the expansion of the corrugated sheet of a corrugated oil tank according to claim 5, characterized in that: The normal pressure expression in S4-1 is: Where P represents the equivalent static pressure, ΔV represents the change in oil volume, V represents the initial oil volume, and K oil Represents the bulk elastic modulus of oil.

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