LNG ship transverse bulkhead block carrying margin measuring method

Abstract

The invention relates to a method for measuring the carrying margin of a transverse bulkhead block of an LNG (Liquefied Natural Gas) ship, which comprises the following steps of: sequentially and respectively carrying out three-dimensional measurement on the constructed transverse bulkhead block and a carrying reference block by utilizing a total station, and then carrying state adjustment and carrying margin analysis on the transverse bulkhead block through carrying simulation software. And then lower bevel edge measuring point coordinates of the transverse bulkhead block model in the simulated carrying final state and corresponding point coordinates of the carrying reference block model are imported into general three-dimensional design software for measurement and analysis, and finally the carrying margin value of the transverse bulkhead block is determined. According to the method, the actual size of the transverse bulkhead block and the actual size of the carrying reference block are collected through three-dimensional measurement and input into simulation carrying software for simulation carrying, then the carrying allowance of the transverse bulkhead block needing to be measured is obtained, the full penetration welding groove is formed after the cutting allowance is accurately removed, and the full penetration welding precision is improved. The transverse bulkhead block and the carrying reference block are tightly attached and carried, and the carrying precision is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to shipbuilding, in particular to a method for measuring the remaining amount of an LNG ship transverse bulkhead section. BACKGROUND

[0002] In the construction of an LNG ship, the transverse bulkhead section is an important structure for dividing the cargo hold area, and has high strength requirements. The butt joint surfaces of the transverse bulkhead section are all full penetration welding grooves. After the transverse bulkhead section is mounted, the transverse bulkhead is closely attached to the mounting reference. If the excess amount is not removed in advance and the groove is not opened, it is difficult to open the groove according to the standard after the mounting.

[0003] After the cargo hold area bottom section and the bottom edge water tank section are mounted, the mounting of the 8-face transverse bulkhead section begins. The bottom surface and the lower inclined surface of the transverse bulkhead section will be butt jointed with the cargo hold area mounting reference. It is necessary to remove the excess amount in advance, open the full penetration welding groove, and then perform the mounting. However, since the excess amount displayed by the simulation mounting software is the difference between the X, Y, and Z values in the three-dimensional coordinates, that is, only the positive direction excess amount is displayed, the excess amount of the lower inclined surface of the transverse bulkhead section cannot be determined. Therefore, the visual excess amount of the lower inclined surface often has errors, which leads to uneven and incomplete cutting, and also leads to errors in opening the full penetration welding groove, thereby hindering the mounting precision and efficiency of the transverse bulkhead section and the mounting reference section. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide a method for measuring the excess amount of an LNG ship transverse bulkhead section. The method of the present application accurately determines the cutting position and the cutting excess amount according to the actual construction progress of the LNG ship transverse bulkhead section and the mounting reference section, so that the subsequent mounting is accurate in position, the butt joint is close, and the mounting is of high quality and high efficiency.

[0005] In order to achieve the above-mentioned purpose of the application, the technical solution provided by the present application is as follows: A method for measuring the excess amount of an LNG ship transverse bulkhead section, when the octahedral transverse bulkhead on the LNG ship is mounted, the bottom surface and the lower inclined surface of the transverse bulkhead section are butt jointed with the mounting reference section. The transverse bulkhead section needs to be cut and removed in advance before being mounted with the mounting reference section. The mounting excess amount to be measured includes the lower bottom surface cutting excess amount and the lower inclined surface cutting excess amount. The feature of the cutting excess amount measurement method comprises the following steps: First, use a total station to perform three-dimensional measurement on the assembled transverse bulkhead section. The first measurement point is the intersection of the bulkhead front and rear walls and the frame, and the intersection of the centerline and the front and rear bulkhead walls. Second step, according to the point of the first measuring point on the transverse bulkhead section, find the corresponding intersection on the loading reference section, and then use the total station to measure the three-dimensional of the loading reference section, the second measuring point is two points on the center line of the inner bottom plate of the loading reference section; The three-dimensional size of the section is obtained by measuring the intersection point, and the three-dimensional coordinates are obtained by space calculation, and the intersection point is measured to obtain the size and shape information of the whole section; Third step, the second measuring point on the loading reference section is introduced into the simulation loading software, the ship X direction is determined according to the two points on the center line of the inner bottom plate, and the transverse state of the loading reference section is determined according to the height value measured by the two symmetrical points on the inner bottom plate, and the actual state of the loading reference section is simulated in the simulation loading software. Fourth step, the first measuring point on the transverse bulkhead section is introduced into the simulation loading software, the state of the transverse bulkhead section model is adjusted, so that the center line of the transverse bulkhead section model coincides with the theoretical center line, and the left and right synchronization is adjusted uniformly. Fifth step, in the simulation loading software, the transverse bulkhead section model and the loading reference section model are simulated, the height and width of the transverse bulkhead section model are adjusted to the theoretical state, and the center line coincidence degree is adjusted to the theoretical state, then the lower bottom surface measuring point of the transverse bulkhead section model is compared with the corresponding measuring point on the loading reference section, and the difference between the Z values of the lower bottom surface measuring point of the transverse bulkhead section model and the corresponding measuring point on the loading reference section is the excess value of the lower bottom surface, that is, the cutting allowance of the lower bottom surface. Sixth step, after the transverse bulkhead section loading state is adjusted in the simulation loading software, the three-dimensional coordinates of the lower inclined surface measuring point and the three-dimensional coordinates of the corresponding point of the loading reference section are read, and the two groups of three-dimensional coordinates are input into the general measuring software, and the vertical difference of each point is measured after connecting into a line, which is the lower inclined surface allowance, that is, the cutting allowance of the lower inclined surface.

[0006] In the measurement method of the transverse bulkhead section loading allowance of the LNG ship, the simulation loading software stores the transverse bulkhead section model and the loading reference section model, and simulates the loading process and state of the transverse bulkhead section model and the loading reference section model, and can display the X, Y and Z values of the three-dimensional coordinates of each point in the model.

[0007] In the measurement method of the transverse bulkhead section loading allowance of the LNG ship, when the transverse bulkhead section and the loading reference section are connected, the bottom of the transverse bulkhead section is the bottom surface, the two sides of the bottom surface are two lower inclined surfaces, and the bottom surface and the lower inclined surface are respectively connected with the top surface and the inclined side surface of the loading reference section.

[0008] In the measuring method of the transverse cabin section of the LNG ship, in the sixth step, the coordinates of the lower inclined edge measuring points of the transverse cabin section and the coordinates of the corresponding points of the loading reference are respectively introduced into Auto cad for analysis, and the vertical difference of each point is measured after being connected into a line, and the excess value of the lower inclined surface is obtained, and finally the excess value of the transverse cabin section is determined.

[0009] In the measuring method of the transverse cabin section of the LNG ship, the excess value of the lower bottom surface and the excess value of the lower inclined surface of the transverse cabin section are obtained, and the lower bottom surface and the lower inclined surface of the transverse cabin section are trimmed, and after the cutting excess is removed, the full penetration welding groove is opened, and the transverse cabin section is closely fitted and loaded with the loading reference section, and the loading precision of the transverse cabin section and the loading reference section is ensured.

[0010] Based on the above invention, the measuring method of the transverse cabin section of the LNG ship is applied in the construction of a plurality of LNG ships, and the following technical effects are achieved: 1. The measuring method of the transverse cabin section of the LNG ship is based on the actual construction of the transverse cabin section and the loading reference section, and the measured three-dimensional data is input into the existing simulation loading software, and the model of the transverse cabin section and the model of the loading reference section are adjusted, and the actual measured value and the theoretical value are compared, so as to obtain the accurate cutting excess.

[0011] 2. In the measuring method of the transverse cabin section of the LNG ship, the simulation loading software is mainly used for adjusting the loading state of the transverse cabin section and analyzing the excess, and the coordinates of the lower inclined edge measuring points of the transverse cabin section in the final state of the simulation loading are introduced into AutoCAD for analysis, and the excess value of the transverse cabin section is determined, and after trimming, the full penetration groove is opened, and finally the high-precision loading of the transverse cabin section is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is a three-dimensional measurement schematic diagram of the transverse cabin section of the LNG ship in the present application.

[0013] Figure 2 It is a three-dimensional measurement schematic diagram of the loading reference section of the LNG ship in the present application.

[0014] Figure 3 It is a three-dimensional data analysis schematic diagram of the transverse cabin section of the LNG ship in the present application.

[0015] Figure 4 It is a three-dimensional data analysis schematic diagram of the loading reference section of the LNG ship in the present application.

[0016] Figure 5The application is a simulation analysis diagram of the simulation docking of the LNG ship transverse bulkhead section and the docking reference section.

[0017] Figure 6 The application is a simulation analysis diagram of the simulation docking of the LNG ship transverse bulkhead section and the docking reference section. DETAILED DESCRIPTION

[0018] The application is a simulation analysis diagram of the simulation docking of the LNG ship transverse bulkhead section and the docking reference section.

[0019] The application is a simulation analysis diagram of the simulation docking of the LNG ship transverse bulkhead section and the docking reference section. Figure 1 — Figure 4 As shown in the figure, Figure 1 As shown in the figure, Figure 2 : The application is a simulation analysis diagram of the simulation docking of the LNG ship transverse bulkhead section and the docking reference section. Figure 3 : The application is a simulation analysis diagram of the simulation docking of the LNG ship transverse bulkhead section and the docking reference section. Figure 4 : The application is a simulation analysis diagram of the simulation docking of the LNG ship transverse bulkhead section and the docking reference section.

[0020] In the docking process, the docking reference section is connected with the transverse bulkhead section, the docking reference section is in a concave shape, including the top surface and the upper inclined surface, and the connecting position line for connecting with the transverse bulkhead section is arranged on the docking reference section, the transverse bulkhead section and the docking reference section are docked to be integrated.

[0021] During the construction of LNG cargo tanks, when mounting transverse bulkheads, the bottom and lower sloping surfaces of the bulkhead assembly are aligned with the mounting reference assembly. The bulkhead assembly needs to have its excess material pre-cut before mounting. This necessitates a new process to measure the mounting allowance. This excess material includes the cutting allowance on the bottom surface of the bulkhead assembly and the cutting allowance on the lower sloping surface. The method for measuring this cutting allowance includes the following steps: First step, such as Figure 1 As shown, a total station is used to perform three-dimensional measurements on the assembled transverse bulkhead section, obtaining the first measurement point. This first measurement point includes the intersections of the bulkhead's fore and aft bulkheads with the frame, as well as the intersections of the mid-length section with the fore and aft bulkheads. In shipbuilding, the three-dimensional dimensions of a section are usually calculated by measuring the three-dimensional coordinates obtained from the intersections of the fore and aft bulkheads with the frame. Measuring these intersections reveals the dimensions, shape, and other information of the entire section.

[0022] The second step involves finding the corresponding intersection point on the completed mounting reference section based on the location of the first measurement point on the transverse bulkhead section. Then, a total station is used to perform a three-dimensional measurement of the mounting reference section. The second measurement point consists of two points on the centerline of the inner floor plate within the mounting reference section. Figure 2 As shown, the three-dimensional dimensions of the entire segment are obtained by measuring the intersection points, obtaining its three-dimensional coordinates, and then performing spatial calculations. Measuring the intersection points is to measure the dimensions and shape of the entire segment.

[0023] The third step is to import the second measurement point on the reference section into the simulation mounting software for three-dimensional data analysis, such as... Figure 4 As shown, the X-direction of the hull is determined by two points on the center line of the inner bottom plate, and the heel state of the loading reference section is determined by measuring the height values ​​of two symmetrical points on the inner bottom plate. Thus, the actual state of the loading reference section is simulated in the loading simulation software. The loading simulation software used in this patent is SPD ship design software from Dongxin Software Company, and is not limited to any particular version number.

[0024] The fourth step involves importing the first measurement point on the transverse bulkhead section into the simulation software, adjusting the state of the transverse bulkhead section model to ensure that the centerline of the model coincides with the theoretical centerline, and uniformly adjusting the left-right synchronization. Then, the three-dimensional data analysis of the transverse bulkhead section is performed in the simulation software. Figure 3 As shown.

[0025] As a conventional existing technology, the simulation loading software stores the overall ship design model of the LNG ship and models of each component section, including the transverse bulkhead section model made according to theoretical dimensions and the loading reference section model. It can simulate the loading process and status of the transverse bulkhead section model and the loading reference section model, and can display the X, Y and Z values ​​of the three-dimensional coordinates of each point in the model.

[0026] Step 5, as Figure 5 As shown, in the simulation software, the transverse bulkhead assembly model and the reference assembly model are simulated for assembly. After adjusting the height, width, and centerline overlap of the transverse bulkhead assembly model to the theoretical state, the measurement points on the bottom surface of the transverse bulkhead assembly model are compared with the corresponding measurement points on the reference assembly. The difference in Z-value between the measurement points on the bottom surface of the transverse bulkhead assembly model and the corresponding measurement points on the reference assembly is the allowance value of the bottom surface of the transverse bulkhead assembly, which is the cutting allowance of the bottom surface. When the transverse bulkhead assembly is docked with the reference assembly, the bottom center of the transverse bulkhead assembly is the bottom surface, and the two sides of the bottom surface are two downward slopes. The bottom surface and the downward slopes are docked with the top surface and the inclined side surface on the reference assembly, respectively.

[0027] Step 6, as follows Figure 6 As shown, after the transverse bulkhead section is adjusted in the simulation loading software, the three-dimensional coordinates of its lower slope measurement point and the three-dimensional coordinates of the corresponding point of the loading reference section are read. The two sets of three-dimensional coordinates are input into the general measurement software, connected into a line, and the vertical difference of each point is measured as the lower slope allowance value, which is the lower slope cutting allowance.

[0028] In the above steps, Figure 5 Within the simulation software, the three-dimensional measurement results of the transverse bulkhead section are matched with the measurement results of the transverse bulkhead section mounting reference surface to obtain the relative deviation value of each point. The deviation value is the margin or clearance. Figure 6 This is because the simulation software analysis results only show the deviation of the point along the positive direction of the ship's length, width, and height. However, there is an angle between the lower slope of the compartment and the positive direction. Therefore, the analysis results need to be presented in AutoCAD, and the margin direction needs to be measured to finally obtain the simulated loading margin value.

[0029] In the final simulated mounting state, the coordinates of the measurement points on the lower inclined side of the transverse bulkhead section and the corresponding coordinates of the mounting reference points were imported into CAD software for analysis. After connecting them into a line, the vertical difference between each point was measured as the lower inclined surface allowance value, thus determining the mounting allowance value of the transverse bulkhead section. Using the obtained allowance values ​​of the lower bottom surface and lower inclined surface of the transverse bulkhead section, the lower bottom surface and lower inclined surface of the transverse bulkhead section were trimmed to remove the cutting allowance. Then, a full penetration welding bevel was created to ensure a tight fit between the transverse bulkhead section and the mounting reference section, guaranteeing the mounting accuracy of the transverse bulkhead section and the mounting reference section.

[0030] Undoubtedly, the above is only a limited implementation of the method for measuring the carrying capacity of the transverse bulkhead section of an LNG carrier, as per this invention patent. Other alternative operating methods and implementation processes are also possible. In conclusion, the scope of protection of this invention patent also includes other variations and substitutions that are obvious to those skilled in the art.

Claims

1. A method for measuring the loading allowance of a transverse bulkhead section on an LNG carrier, wherein when loading an octahedral transverse bulkhead on an LNG carrier, the bottom surface and lower inclined surface of the transverse bulkhead section are aligned with a loading reference section, the transverse bulkhead section needs to be pre-cut to remove any remaining allowance before being loaded with the loading reference section, and the loading allowance to be measured includes the cutting allowance of the bottom surface and the cutting allowance of the lower inclined surface, characterized in that... The method for measuring the cutting allowance includes the following steps: The first step is to use a total station to perform a three-dimensional measurement of the transverse bulkhead section after assembly. The first measurement points are the intersections of the front and rear bulkheads of the bulkhead with the frame, and the intersections of the central longitudinal section with the front and rear bulkheads. The second step is to find the corresponding intersection point on the mounting reference section based on the location of the first measurement point on the transverse bulkhead section, and then use a total station to perform three-dimensional measurement on the mounting reference section. The second measurement point is two points on the center line of the inner bottom plate in the mounting reference section. The third step is to import the second measurement point on the mounting reference section into the simulation mounting software, determine the hull X direction based on two points on the center line of the inner bottom plate, determine the heel state of the mounting reference section based on the height values ​​measured at two symmetrical points on the inner bottom plate, and simulate the actual state of the mounting reference section in the simulation mounting software. The fourth step is to import the first measurement point on the transverse bulkhead section into the simulation software, adjust the state of the transverse bulkhead section model so that the center line of the transverse bulkhead section model coincides with the theoretical center line, and adjust the left and right synchronization evenly. The fifth step is to simulate the assembly of the transverse bulkhead section model and the assembly reference section model in the simulation software. After adjusting the height, width, and centerline overlap of the transverse bulkhead section model to the theoretical state, the measurement points on the bottom surface of the transverse bulkhead section model are compared with the corresponding measurement points on the assembly reference section. The difference between the Z values ​​of the measurement points on the bottom surface of the transverse bulkhead section model and the corresponding measurement points on the assembly reference section is the allowance value of the bottom surface of the transverse bulkhead section, which is the cutting allowance of the bottom surface. Step 6: After the transverse bulkhead section is adjusted in the simulation software, read the three-dimensional coordinates of its lower slope measurement point and the three-dimensional coordinates of the corresponding point of the mounting reference section. Input the two sets of three-dimensional coordinates into the general measurement software, connect them into a line, and measure the vertical difference of each point as the lower slope allowance value, which is the lower slope cutting allowance.

2. The method for measuring the carrying capacity of the transverse bulkhead section of an LNG carrier according to claim 1, characterized in that, The simulation loading software stores a transverse bulkhead assembly model and a loading reference assembly model, and simulates the loading process and status of the transverse bulkhead assembly model and the loading reference assembly model, and can display the X, Y and Z values ​​in the three-dimensional coordinates of each point in the model.

3. The method for measuring the carrying capacity of the transverse bulkhead section of an LNG carrier according to claim 1, characterized in that, When the transverse bulkhead section is docked with the mounting reference section, the bottom center of the transverse bulkhead section is the bottom surface, and the two sides of the bottom surface are two downward slopes. The bottom surface and the downward slopes are docked with the top surface and the inclined side surface of the mounting reference section, respectively.

4. The method for measuring the carrying capacity of the transverse bulkhead section of an LNG carrier according to claim 1, characterized in that, In the sixth step, under the simulated final loading state, the coordinates of the measurement points on the lower slope of the transverse bulkhead section and the corresponding coordinates of the loading reference points are imported into AutoCAD for analysis. After connecting them into a line, the vertical difference between each point is measured as the lower slope margin value, and the loading margin value of the transverse bulkhead section is finally determined.

5. The method for measuring the carrying capacity of the transverse bulkhead section of an LNG carrier according to claim 1, characterized in that, Using the obtained allowance values ​​of the bottom surface and the bottom slope of the transverse bulkhead section, the bottom surface and the bottom slope of the transverse bulkhead section are trimmed to remove the cutting allowance. Then, the full penetration welding bevel is opened to achieve a tight fit between the transverse bulkhead section and the mounting reference section, ensuring the mounting accuracy between the transverse bulkhead section and the mounting reference section.

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