Calculation Method, System, Medium and Electronic Device for Pressure and Plate Thickness of Ship Liquid Tank

Abstract

The present invention provides a method, a system, a medium and an electronic device for calculating the pressure and plate thickness of a ship liquid tank. Among them, the method includes creating a curved surface of the liquid tank outer shell plate by using a parametric template; taking a reference point on the curved surface of the liquid tank outer shell plate to create a three-dimensional surface so as to obtain the maximum value of the internal pressure of the liquid at the reference point; calculating the maximum value of the internal pressure of the liquid tank at each reference point on the curved surface of the liquid tank outer shell plate, and calculating the thickness value of the liquid tank outer shell plate according to the maximum value of the pressure. The method, system, medium and electronic device for calculating the pressure and plate thickness of the ship liquid tank according to the present invention create a curved surface of the liquid tank outer shell plate by inputting geometric shape parameters, and then obtain the thickness of the outer shell plate through the created curved surface of the liquid tank outer shell plate, the input liquid parameters in the liquid tank and the ship parameters. The operation is simple and convenient, the integration level is high, and it is applicable to various types of ship liquid tanks, greatly improving the efficiency of pressure calculation in ship liquid tank design.

Description

Technical Field

[0001] The present invention relates to the technical field of ship design, and particularly to a method, system, medium and electronic device for calculating the pressure and plate thickness of a ship liquid tank. Background Art

[0002] The internal pressure of a liquid tank is an important parameter to be considered in the initial stage of the liquid tank structure design. Its value determines the thickness of the plate of the liquid tank shell. The new edition of the "International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk" (IGC Code) that came into effect in 2016 compulsorily requires the use of the ellipsoid method including three-direction acceleration components to calculate the internal pressure of the liquid tank of a liquefied gas carrier. Usually, the discrete method is used to calculate the maximum pressure inside the liquid tank, that is, the liquid tank shell is discretized into a series of discrete points, and several reference points (usually the reference points of the outer shell plate) are selected, and then the formula is used to calculate the internal pressure value of the liquid at each discrete point corresponding to the reference point, and the maximum value is taken.

[0003] The calculation accuracy of the discrete method depends on the number of discrete points. The more the number of discrete points, the more accurate the calculation result and the smaller the calculation error; on the contrary, the calculation error is larger, and the increase in the number of discrete points will also lead to a multiple increase in the calculation amount and an extension of the calculation time. At the same time, the discretization process of the liquid tank model is usually generated by means of finite element mesh division, which involves multi-platform operations, model conversion, data extraction and calculation. The operation process is more, the calculation efficiency is lower, and it is easy to produce errors and omissions. Therefore, a method with higher efficiency is needed to handle this problem. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a method, system, medium and electronic device for calculating the pressure and plate thickness of a ship liquid tank, which is used to solve the problem of low pressure calculation efficiency in the design of ship liquid tanks in the prior art.

[0005] To achieve the above purpose and other related purposes, the present invention provides a method for calculating the pressure and plate thickness of a ship liquid tank, the method comprising: creating a liquid tank outer shell plate surface by using a parametric template; taking a reference point on the liquid tank outer shell plate surface to create a three-dimensional surface to obtain the maximum value of the internal pressure of the liquid at the reference point; calculating the maximum value of the internal pressure of the liquid tank at each reference point on the liquid tank outer shell plate surface, and calculating the liquid tank outer shell plate thickness value according to the maximum pressure value.

[0006] In an embodiment of the present invention, the method further comprises creating a three-dimensional model of the liquid tank outer shell plate according to the liquid tank outer shell plate surface and the outer shell plate thickness value.

[0007] In an embodiment of the present invention, the method further comprises adding the material information of the outer shell plate and the outer shell plate thickness value information to the three-dimensional model in the form of attributes.

[0008] In an embodiment of the present invention, by inputting geometric shape parameters, the liquid tank outer shell plate surface is created using the parametric template.

[0009] In an embodiment of the present invention, taking a reference point on the liquid tank outer shell plate surface to create a three-dimensional surface and obtaining the maximum value of the internal liquid pressure at the reference point specifically includes:

[0010] Obtaining each reference point on the liquid tank outer shell plate surface;

[0011] Taking one of the reference points and fixing the internal liquid pressure value at the reference point to create the corresponding three-dimensional surface;

[0012] By adjusting the internal liquid pressure value at the reference point and using the bisection method to iteratively solve the surface equation successively to adjust the three-dimensional surface;

[0013] Based on the premise that the three-dimensional surface intersects with the liquid tank outer shell plate surface, obtaining the maximum value of the internal liquid pressure at the reference point.

[0014] In an embodiment of the present invention, the method further includes judging each reference point on the liquid tank outer shell plate surface.

[0015] In an embodiment of the present invention, if the included angle is less than a preset value, the intersection point of adjacent topological edges is taken as the reference point; otherwise, this intersection point is not taken as the reference point.

[0016] To achieve the above object and other related objects, the present invention provides a calculation system for the pressure and plate thickness of a ship's liquid tank as described above. The system includes:

[0017] A creation module for creating the liquid tank outer shell plate surface using a parametric template;

[0018] An acquisition module for taking a reference point on the liquid tank outer shell plate surface to create a three-dimensional surface to obtain the maximum value of the internal liquid pressure at the reference point;

[0019] A calculation module for calculating the maximum value of the internal liquid pressure at each reference point on the liquid tank outer shell plate surface and calculating the liquid tank outer shell plate thickness value according to the maximum pressure value.

[0020] To achieve the above object and other related objects, the present invention provides a computer-readable storage medium as described above, on which a computer program is stored, and when the program is executed by a processor, the calculation method for the pressure and plate thickness of the ship's liquid tank is implemented.

[0021] To achieve the above and other related objectives, the present invention provides an electronic device as described above. The electronic device includes: a memory for storing a computer program, and a processor for loading and executing the computer program so that the electronic device executes the method for calculating the pressure and plate thickness of a ship liquid tank as described above.

[0022] As described above, the method, system, medium, and electronic device for calculating the pressure and plate thickness of a ship liquid tank according to the present invention create a liquid tank outer shell plate surface by inputting geometric shape parameters to obtain the outer shell plate thickness. The operation is simple and convenient, the integration level is high, and it is applicable to various types of ship liquid tanks, greatly improving the efficiency of pressure calculation in ship liquid tank design. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It shows a method step diagram of the method for calculating the pressure and plate thickness of a ship liquid tank according to the present invention in an embodiment;

[0024] Figure 2 It shows a method step diagram of the method for calculating the pressure and plate thickness of a ship liquid tank according to the present invention in another embodiment;

[0025] Figure 3 It shows a three-dimensional surface schematic diagram of the method for calculating the pressure and plate thickness of a ship liquid tank according to the present invention in an embodiment;

[0026] Figure 4 It shows a structural schematic diagram of the system for calculating the pressure and plate thickness of a ship liquid tank according to the present invention in an embodiment;

[0027] Figure 5 It shows a structural schematic diagram of an electronic device according to an embodiment of the present invention.

[0028] DESCRIPTION OF REFERENCE NUMERALS

[0029] Steps S11 - S13

[0030] Steps S21 - S24

[0031] 40 System for calculating the pressure and plate thickness of a ship liquid tank

[0032] 41 Creation module

[0033] 42 Acquisition module

[0034] 43 Calculation module DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0036] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0037] Please refer to Figure 1 , in an embodiment of the invention, the calculation method for the pressure and plate thickness of a ship's liquid tank of the present invention includes the following steps:

[0038] Step S11: Create a liquid tank outer shell plate surface using a parametric template;

[0039] Step S12: Take a reference point on the liquid tank outer shell plate surface to create a three-dimensional surface to obtain the maximum value of the internal liquid pressure at the reference point;

[0040] Step S13: Calculate the maximum value of the internal liquid pressure at each reference point on the liquid tank outer shell plate surface, and calculate the thickness value of the liquid tank outer shell plate according to the maximum pressure value.

[0041] It should be noted that based on the liquid tank design parameters (i.e., geometric shape parameters) input by the user, the liquid tank outer shell plate surface is created through the parametric template, and the extreme values x min 、y min 、z min 、x max 、y max and z max of the liquid tank outer shell plate surface in the XYZ three directions are calculated. Among them, the parametric template is a standard template. Each reference point on the liquid tank outer shell plate surface is obtained, a reference point is taken to create a three-dimensional surface, and the maximum value of the internal liquid pressure at the reference point is obtained. Further, as Figure 2 shown, it specifically includes the following steps:

[0042] Step S21: Obtain each reference point on the liquid tank outer shell plate surface;

[0043] Step S22, taking a reference point, fixing the internal pressure value of the liquid at the reference point to create the corresponding three-dimensional curved surface;

[0044] Step S23, adjusting the internal pressure value of the liquid at the reference point and iterating the surface equation successively by using the dichotomy method to adjust the three-dimensional surface;

[0045] Step S24: based on the premise that the three-dimensional curved surface intersects with the curved surface of the outer shell plate of the liquid tank, the maximum internal pressure of the liquid at the reference point is obtained.

[0046] Specifically, the ellipsoid method including acceleration components in three directions is used to calculate the internal pressure of the liquid tank of the liquefied gas carrier, and the calculation formula is:

[0047] P eq =P0+(P gd ) max ; (1)

[0048] Among them, P eq is the internal pressure of the liquid tank, P0 is the steam pressure, P gd is the internal pressure of the liquid. When calculating the pressure, P0 is a known quantity, and only P gd Therefore, the P of any point on the tank shell relative to another point gd The calculation formula is:

[0049]

[0050] Where ρ is the maximum density of liquid cargo that can be loaded in the tank at the design temperature, g is the acceleration of gravity, and a is x 、a y 、a z are longitudinal, lateral and vertical dimensionless acceleration components respectively, (x1, y1, z1) is used to calculate (P gd ) max The coordinates of the reference point, (x, y, z) are the coordinates of any point on the surface of the tank shell, and P can be obtained based on formula (2). gd is the surface represented by a certain constant, and then by adjusting the internal pressure value P of the liquid gd , the surface equation is iterated by bisection method, the three-dimensional surface is adjusted, and based on the premise that the three-dimensional surface intersects with the surface of the tank shell plate, the maximum internal pressure of the liquid under a given accuracy (P gd ) max , where the accuracy can be taken as the time between two calculations (P gd ) max The change is less than "0.001Mpa", and the three-dimensional surface here is actually the internal pressure value P of the liquid gdTake different values ​​for the corresponding different surfaces, take a reference point, and calculate P based on formula (2) when x, y, z take extreme values ​​at this reference point gd The maximum value of (P gd ) max As an rvalue P gd-r , since the right value P gd-r is the reference point (P gd ) max , so the P of any point on the surface of the liquid tank at the reference position gd are both less than the right value P gd-r , take the left value P gd-l is zero, at this time the discrete point on the tank is the reference point itself, so the reference point (P gd ) max Must be located on the left value P gd-l With the rvalue P gd-r between.

[0051] Further, take the left value P gd-l With the rvalue P gd-r The average value P gd-m , the average value P gd-m Substituting into formula (2), a three-dimensional surface with variables (x, y, z) is created. Specifically, the three-dimensional surface, reference point, and tank surface are as follows: Figure 3 As shown, get the distance between the three-dimensional surface and the liquid tank surface. If the distance is greater than zero, set the right value P gd-r Equal to the average value P gd-m , if the distance is zero, calculate P gd-r -P gd-m Is the value of less than the given tolerance? If so, output (P gd ) max =P gd-m , otherwise, let the left value P gd-l Equal to the average value P gd-m , where the given tolerance is the given accuracy, which can be "0.001Mpa".

[0052] Furthermore, the P at each reference point on the tank shell plate is calculated by formula (1): eq Since P0 is a known quantity, P eq The maximum value of the internal pressure of the liquid can be calculated based on the maximum value of the internal pressure of the liquid (P gd ) max To obtain, and then calculate the tank shell thickness value, specifically according to the relevant classification society specifications to calculate the tank shell thickness, in this embodiment, taking Lloyd's Register as an example, the tank plate thickness calculation formula is as follows:

[0053]

[0054]

[0055] t ≥ D i / 1500 + 3mm;(5)

[0056] Wherein, t is the thickness of the liquid tank plate, and D i is the diameter of the liquid tank plate, and σ m is the material strength. Among them, formula (3) is applicable to the calculation of the thickness of the cylindrical shell plate, formula (4) is applicable to the calculation of the thickness of the spherical head plate, and formula (5) is applicable to the calculation of the thickness of all liquid tank plates.

[0057] It is worth mentioning that the method further includes judging each reference point on the surface of the liquid tank outer shell plate, obtaining the reference point by calculating the included angle between adjacent topological edges on the surface of the liquid tank outer shell plate. If the included angle is greater than a preset value, the intersection of the adjacent topological edges is used as the reference point; otherwise, the intersection is not used as the reference point. Preferably, the preset value can be selected as 160°.

[0058] It is worth mentioning that in an embodiment of the invention, the method further includes creating a three-dimensional model of the liquid tank outer shell plate according to the surface of the liquid tank outer shell plate and the value of the outer shell plate thickness.

[0059] It should be noted that according to the created surface of the liquid tank outer shell plate and the value of the liquid tank outer shell plate thickness, the three-dimensional model can be created, and then the material information of the outer shell plate and the information of the outer shell plate thickness value are added to the three-dimensional model in the form of attributes for visual display.

[0060] Please refer to Figure 4 , in an embodiment, a calculation system 40 for the pressure and plate thickness of a ship liquid tank provided in this embodiment, the system includes:

[0061] A creation module 41, configured to create a surface of the liquid tank outer shell plate by using a parametric template;

[0062] An acquisition module 42, which takes a reference point on the surface of the liquid tank outer shell plate to create a three-dimensional surface, so as to obtain the maximum value of the internal pressure of the liquid at the reference point;

[0063] A calculation module 43, configured to calculate the maximum value of the internal pressure of the liquid tank at each reference point on the surface of the liquid tank outer shell plate, and calculate the thickness value of the liquid tank outer shell plate according to the maximum pressure value.

[0064] Since the specific implementation manner of this embodiment corresponds to the foregoing method embodiment, the same details will not be repeated here. Those skilled in the art should also understand that Figure 4The division of each module in the embodiments is only a division of logical functions. In actual implementation, all or part of them can be integrated into one or more physical entities. And these modules can all be implemented in the form of software called by processing elements, or all be implemented in the form of hardware, or some modules be implemented in the form of software called by processing elements and some modules be implemented in the form of hardware.

[0065] In addition, the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the calculation method of the pressure and plate thickness of any ship liquid tank described above.

[0066] Refer to Figure 5 , this embodiment provides an electronic device. Specifically, the electronic device at least includes: a memory and a processor connected by a bus. Among them, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to execute all or part of the steps in the foregoing method embodiments.

[0067] In summary, the present invention creates the liquid tank outer shell plate surface by inputting geometric shape parameters, and then obtains the outer shell plate thickness through the created liquid tank outer shell plate surface, the input liquid parameters in the liquid tank and the ship parameters. The operation is simple and convenient, the degree of integration is high, and it is applicable to various types of ship liquid tanks, greatly improving the efficiency of pressure calculation in ship liquid tank design.

[0068] The above embodiments are only illustrative of the principles and effects of the present invention, and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A calculation method for the pressure and plate thickness of a ship's liquid tank, characterized in that, Including: Creating the curved surface of the liquid tank outer shell plate using a parametric template; Taking a reference point on the curved surface of the liquid tank outer shell plate to create a three-dimensional surface so as to obtain the maximum value of the internal pressure of the liquid at the reference point, where specifically it includes: obtaining each reference point on the curved surface of the liquid tank outer shell plate; taking one of the reference points, fixing the internal pressure value of the liquid at the reference point to create the corresponding three-dimensional surface; by adjusting the internal pressure value of the liquid at the reference point, using the bisection method to iteratively solve the surface equation successively to adjust the three-dimensional surface; based on the premise that the three-dimensional surface intersects with the curved surface of the liquid tank outer shell plate, obtaining the maximum value of the internal pressure of the liquid at the reference point; Calculating the maximum value of the internal pressure of the liquid tank at each reference point on the curved surface of the liquid tank outer shell plate, and calculating the thickness value of the liquid tank outer shell plate according to the maximum pressure value.

2. The calculation method of the pressure and plate thickness of the ship liquid tank according to claim 1, characterized in that, The method further includes creating a three-dimensional model of the liquid tank outer shell plate according to the curved surface of the liquid tank outer shell plate and the thickness value of the outer shell plate.

3. The calculation method of the pressure and plate thickness of the ship liquid tank according to claim 2, characterized in that The method further includes adding the material information of the outer shell plate and the information of the thickness value of the outer shell plate to the three-dimensional model in the form of attributes.

4. The calculation method of the pressure and plate thickness of the ship liquid tank according to claim 1, characterized in that, Creating the curved surface of the liquid tank outer shell plate using the parametric template by inputting geometric shape parameters.

5. The calculation method of the pressure and plate thickness of the ship's liquid tank according to claim 1, characterized in that, The method further includes judging each reference point on the curved surface of the liquid tank outer shell plate.

6. The calculation method of the pressure and plate thickness of the ship's liquid tank according to claim 5, characterized in that, If the included angle is less than a preset value, then taking the intersection point of adjacent topological edges as the reference point; otherwise, this intersection point is not taken as the reference point.

7. A calculation system for the pressure and plate thickness of a ship's liquid tank, characterized in that, Including: A creating module for creating the curved surface of the liquid tank outer shell plate using a parametric template; An obtaining module for taking a reference point on the curved surface of the liquid tank outer shell plate to create a three-dimensional surface so as to obtain the maximum value of the internal pressure of the liquid at the reference point, where specifically it includes: obtaining each reference point on the curved surface of the liquid tank outer shell plate; taking one of the reference points, fixing the internal pressure value of the liquid at the reference point to create the corresponding three-dimensional surface; by adjusting the internal pressure value of the liquid at the reference point, using the bisection method to iteratively solve the surface equation successively to adjust the three-dimensional surface; based on the premise that the three-dimensional surface intersects with the curved surface of the liquid tank outer shell plate, obtaining the maximum value of the internal pressure of the liquid at the reference point; A calculating module for calculating the maximum value of the internal pressure of the liquid tank at each reference point on the curved surface of the liquid tank outer shell plate, and calculating the thickness value of the liquid tank outer shell plate according to the maximum pressure value.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by a processor, it implements the calculation method of the pressure and plate thickness of the ship liquid tank according to any one of claims 1 to 6.

9. An electronic device, characterized in that, The electronic device includes: a processor and a memory; wherein, the memory is used for storing a computer program, and the processor is used for executing the computer program stored in the memory so that the electronic device executes the calculation method of the pressure and plate thickness of the ship liquid tank according to any one of claims 1 to 6.

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