Method for controlling accuracy of a transom round line of an LNG ship and a transom section

Abstract

The application relates to a method for controlling the accuracy of a transom round line type of an LNG ship and a transom section, which comprises the following steps: temporarily not welding after splicing the transom plate area, selecting a plurality of management points along the line type of the transom plate, selecting a plurality of theoretical management points in the model of the transom section in the ECO-BLOCK software, and corresponding one-to-one correspondence between the management point marks and the theoretical management points; taking the first and last theoretical management points as the horizontal reference in the ECO-BLOCK software, obtaining the distance l of the remaining theoretical management points from the horizontal reference; pulling a line rope between the first and last management point marks, measuring the vertical distance L of the management point marks from the line rope, if the deviation between L and l is within 3mm, the line type meets the requirements, and if the deviation exceeds 3mm, the line type of the transom plate area is adjusted, and the spliced plate joints are welded after adjustment. The application can greatly improve the efficiency of the section construction by measuring on site in a two-dimensional way, adjusting the line type according to the two-dimensional measurement results, and reducing the time for three-dimensional measurement and analysis.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding, specifically to a method for controlling the accuracy of the bilge profile of an LNG carrier and a bilge section. Background Technology

[0002] Currently, the construction precision of LNG ship bilge sections is becoming increasingly refined. Circumference control typically employs three-dimensional inspection. If the circumference is too large, it requires cutting or heat treatment; if it is too small, it also requires cutting. As long as corrections are made, the circumference accuracy of the circumference section cannot be guaranteed to be completely satisfactory and smooth. This severely impacts the accuracy of subsequent section assembly and mounting, significantly hindering the high efficiency of shipbuilding. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method and bilge section for controlling the accuracy of bilge styling during circular transitions in LNG vessels. This method achieves accurate control of the bilge styling during circular transitions, reduces the time required for three-dimensional measurement and analysis, and improves construction efficiency.

[0004] The technical objective of this invention is achieved through the following technical solution:

[0005] A method for controlling the accuracy of the bilge profile of an LNG carrier during circular turning, the method comprising the following steps:

[0006] Step 1: Assemble the inner bottom plate and the rotating plate of the bilge section on the jig;

[0007] Step 2: After the panels are assembled, weld the joints of the inner bottom plate. Do not weld the joints of the round plate yet. Mark lines on the inner bottom plate and the round plate, and install the components according to the marked lines.

[0008] Step 3: Select several management points at equal intervals along the outer linear plate of the rotating plate. The first management point is marked as point A, and the last management point is marked as point B. Point A and point B are connected by a string. Measure the vertical distance L between the management point mark and the string between points A and B.

[0009] Using ECO-BLOCK software, select several theoretical management points at equal intervals in the bilge segment model, corresponding to the management point markers. The spacing between theoretical management points is the same as the spacing between management point markers. The first theoretical management point is 'a', and the last theoretical management point is 'b'. Adjust the angle of the bilge segment model in ECO-BLOCK software so that the line ab connecting points a and b is horizontal. Record the vertical distance l between the theoretical management point and the line ab in ECO-BLOCK software.

[0010] Step 4: Compare the values ​​of L and l. If the deviation between L and l is greater than 3mm, the splicing plates of the rotating plate need to be adjusted to adjust the shape of the rotating plate until the deviation between L and l is ≤3mm. Then, weld the splicing plate seams of the rotating plate.

[0011] Further, in step 3, the distance from point a to the foot of the perpendicular from the theoretical management point between points a and b to the line ab is m. Based on m, starting from point A, measure the position of the perpendicular from the management point mark between points A and B to the line. The distance between the position of the perpendicular on the line and the corresponding management point mark is L.

[0012] Furthermore, before assembling the inner bottom plate and the round plate, the outer plates of the bilge section are also cut and assembled. During the cutting process, the length accuracy of the inner bottom plate assembly is controlled within ±1mm and the diagonal accuracy is controlled within ±3mm.

[0013] Furthermore, the outer panel at the rounded position after cutting is cold-bent. The accuracy of the length and width of the cold-bent outer panel is controlled within ±1mm, and the accuracy of the line shape is controlled within ±2mm.

[0014] Furthermore, in step 1, the end face accuracy after splicing is controlled within ±2mm, and the length and width accuracy after splicing are controlled within ±1mm; the horizontal accuracy of the end face of the top edge of the rotating plate is controlled within ±3mm.

[0015] Furthermore, in step 3, point A is determined along the outer edge of the rotating plate, starting from the first component on the rotating plate.

[0016] Furthermore, in step 3, the spacing between theoretical management points and the spacing between management point markers are both 500mm.

[0017] Furthermore, after step 4 is completed, the alignment of the bilge segment at the turning point is re-measured and recorded; the re-measured alignment of the bilge segment to be connected is compared with the alignment of the bilge segment to be connected. If the alignment of the bilge segment to be connected matches, it meets the requirements; if the alignment of the bilge segment to be connected does not match, the alignment of the bilge segment is corrected.

[0018] The present invention also provides an LNG ship bilge section, which performs bilge rotation accuracy control according to the above method.

[0019] Compared to existing technologies, the advantages of this invention are that it controls the accuracy of the bilge hull shape transition of LNG ships using a two-dimensional method on-site. The hull shape is adjusted based on the two-dimensional measurement results, and then the bilge hull shape transition is controlled again after the adjustment is completed. This reduces the time required for three-dimensional measurement and analysis, and can significantly improve the efficiency of segmented construction. In addition, compared to measuring and correcting the accuracy of the hull shape transition after welding, it can reduce the amount of correction and reduce the impact of the correction process on the hull shape. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the inner bottom plate and rotating plate assembly of the bilge section in this invention.

[0021] Figure 2 This is a schematic diagram of the installation of components on the inner bottom plate and rotating plate of the bilge section in this invention.

[0022] Figure 3 This is a schematic diagram of the theoretical management point setting in this invention.

[0023] Figure 4 This is a schematic diagram of the management point marking settings in this invention. Detailed Implementation

[0024] The technical solution of the present invention will be further described below with reference to specific embodiments:

[0025] A method for controlling the accuracy of the bilge profile of an LNG carrier during circular turning, the method comprising the following steps:

[0026] Step 1: On the jig, assemble the inner bottom plate and the rotating plate of the bilge section, as follows: Figure 1 As shown;

[0027] Before assembly, the materials used for assembling the inner base plate area and the outer plate of the turntable area need to be cut. For the materials used for assembling the inner base plate 1, the length accuracy of each individual material is controlled within ±1mm, and the diagonal accuracy within ±3mm. For the materials used for assembling the turntable 2, after cutting, the materials are bent using a cold bending process. The length and width accuracy of the cold-bent materials are both controlled within ±1mm, and the line accuracy is controlled within ±2mm. This precision control during cutting reduces errors in subsequent assembly.

[0028] During the assembly process, the assembly is carried out on the jig. The jig manufacturing accuracy is controlled within ±2mm. After the jig accuracy is qualified, the assembly operation is carried out. The end face accuracy of the assembled plate is controlled within ±2mm, and the length and width accuracy of the assembled plate are controlled within ±1mm. The horizontal accuracy of the end face of the top 4 of the round plate is controlled within ±3mm.

[0029] Step 2: After the panels are assembled, weld the joints of the inner bottom plate 1. Do not weld the joints of the rotating plate 2 yet (the joint between the inner bottom plate and the rotating plate needs to be welded). Using the midship side and bow as references, mark the transverse and longitudinal components according to the marking construction drawings to determine the installation positions of the transverse and longitudinal components. The marking accuracy should be controlled within ±2mm. Then install the transverse and longitudinal components according to the marked positions.

[0030] Step 3, as follows Figure 3 As shown, several management points are selected at equal intervals along the linear outer plate of the rotating plate. The first management point is marked as point A. Figure 4 As shown, in this embodiment, point A is determined with the first component 3 (T row) on the rotating plate as the starting point along the outer plate of the rotating plate. A management point mark is determined every 500mm along the outer plate, and the last management point mark is point B. Point A and point B are connected by a rope. The vertical distance L between the management point mark and the rope between point A and point B is measured.

[0031] Using ECO-BLOCK software, select several theoretical management points at equal intervals in the model corresponding to the management point markers. The spacing between theoretical management points is the same as the spacing between management point markers. The first theoretical management point is 'a'. Along the outer plate's line, determine a theoretical management point every 500mm in the model. Point 'a' is taken as the starting point of the first component on the circular plate in the bilge segment model, and the last theoretical management point is 'b'. Adjust the angle of the bilge segment model in ECO-BLOCK software so that the line 'ab' connecting points 'a' and 'b' is horizontal. Record the vertical distance 'l' between the theoretical management point and the line 'ab' in ECO-BLOCK software.

[0032] Specifically, 11 management point markers were selected on the linear outer plate of the rotating plate, with the first being point A and the last being point B. There are 9 management point markers between point A and point B. Correspondingly, 11 theoretical management points were also selected in the model of the bilge segment, with the first being point a, which has the same starting position as point A, and the last being point b. There are 9 theoretical management points between point a and point b.

[0033] With line ab horizontal, the 3D coordinates (X, Y, Z) of each theoretical management point under this horizontal condition are obtained using ECO-BLOCK software. The coordinates of point a are (0, 0, 0), and the coordinates of point b are (0, 4510, 0). The coordinates of the nine theoretical management points between points a and b are (0, 398, -302), (0, 835, -543), (0, 1303, -718), (0, 1792, -823), (0, 2290, -854), (0, 278), and (0, 278). 8, -813), (0, 3274, -698), (0, 3738, -513), (0, 4171, -264); The perpendicular distance of these 9 theoretical management points between point a and point b from the line ab is also the Z value (i.e., l) of the coordinates. Taking the second theoretical management point as an example, its distance from the line ab is 302. Draw a perpendicular line from the second theoretical management line to the line ab, and denote the foot of the perpendicular as c. The distance of the foot of the perpendicular c from point a on the line ab is the Y value (i.e., m is the Y coordinate value). The distance between point c and point a is 398.

[0034] On the actual rotating plate's outer linear plate, the theoretical vertical distance between the second management point mark and the line AB is 302. The actual vertical distance L between the second management point mark and the line AB is measured using a measuring tape.

[0035] To facilitate measurement with a measuring tape, starting from point A, measure the position of the perpendicular foot along the line AB according to the Y value of the theoretical management point. Directly measure the distance between the management point mark and the corresponding perpendicular foot, which is the vertical distance (L) from the management point mark to the line AB. Use this method to measure the vertical distances of the 9 management point marks between points A and B from the line AB.

[0036] Step 4: Compare the values ​​of L and l. If the deviation between L and l is greater than 3mm, the splicing plates of the rotating plate need to be adjusted to adjust the shape of the rotating plate until the deviation between L and l is ≤3mm. Then, weld the splicing plate seams of the rotating plate.

[0037] After step 4 is completed, the alignment of the bilge section at the turning point is re-measured and recorded. The re-measured alignment of the bilge section to be docked is compared with the alignment of the bilge section to be docked. If the alignment of the bilge section to be docked matches, it meets the requirements; if the alignment of the bilge section to be docked does not match, the alignment of the bilge section is corrected. This embodiment also provides an LNG ship bilge section, which is constructed with precision control according to the above method to ensure that the accuracy meets the requirements after construction and improves construction efficiency.

[0038] This embodiment is merely a further explanation of the present invention and is not intended to limit the present invention. Those skilled in the art can make non-inventive modifications to this embodiment as needed after reading this specification, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for controlling the accuracy of a bilge round-bulb line of an LNG carrier, characterized by, The method comprises the following steps: Step 1, performing inner bottom plate splicing and turning plate splicing of the bilge section on a cradle; Step 2, after the splicing is completed, performing splicing seam welding on the inner bottom plate, and the splicing seam of the turning plate is not welded temporarily; performing line marking on the inner bottom plate and the turning plate, and installing components according to the line marking; Step 3, selecting a plurality of management point marks along the line type outer plate of the turning plate at equal intervals, the first management point mark is A point, and the last management point mark is B point, the A point and the B point are connected through a line rope, and the vertical distance L of the management point mark between the A point and the B point from the line rope is measured; a plurality of theoretical management points are selected at equal intervals in the model of the bilge section corresponding to the management point marks by using ECO-BLOCK software, the interval between the theoretical management points is the same as the interval between the management point marks, the first theoretical management point is a, and the last theoretical management point is b, the angle of the model of the bilge section is adjusted in the ECO-BLOCK software so that the line ab between the a point and the b point is in a horizontal state, and the vertical distance l of the theoretical management point between the a point and the b point from the line ab in the ECO-BLOCK software is recorded; Step 4, comparing the values of L and l, if the deviation between L and l is greater than 3 mm, the splicing of the turning plate needs to be adjusted to adjust the line type of the turning plate until the deviation between L and l is less than or equal to 3 mm, and then the splicing seam of the turning plate is welded.

2. A method of controlling the accuracy of a bilge round line of an LNG ship according to claim 1, wherein, In the step 3, the distance from the foot point a of the perpendicular line to the ab line through the theoretical management points between the a point and the b point is m, the positions of the perpendicular feet of the management point marks between the A point and the B point from the line rope are measured from the A point as the starting point along the line rope according to m, and the distance between the position of the perpendicular foot on the line rope and the corresponding management point mark is L.

3. A method for controlling the accuracy of a bilge round line of an LNG ship according to claim 1, wherein, Before the inner bottom plate splicing and the turning plate splicing are performed, the outer plate of the bilge section is also subjected to splicing blanking and cutting, and the length accuracy of the plate material for the inner bottom plate splicing is controlled within ±1 mm, and the diagonal accuracy is controlled within ±3 mm.

4. A method of controlling the accuracy of a bilge round line of an LNG ship according to claim 3, wherein The outer plate at the turning position is subjected to cold bending treatment after the blanking and cutting, and the length and width accuracies of the cold-bent outer plate are both controlled within ±1 mm, and the line type accuracy is controlled within ±2 mm.

5. A method of controlling the accuracy of a bilge round line of an LNG ship according to claim 4, wherein The end face accuracy after the splicing in the step 1 is controlled within ±2 mm, the length and width accuracies after the splicing are controlled within ±1 mm, the horizontal accuracy of the end face of the upper opening of the turning plate is controlled within ±3 mm.

6. A method of controlling the accuracy of a bilge round line of an LNG ship according to claim 1, wherein, In the step 3, the A point is determined along the line type outer plate of the turning plate with the first component on the turning plate as the starting point.

7. A method of controlling the accuracy of a bilge round line of an LNG ship according to claim 1, wherein In the step 3, the interval between the theoretical management points and the interval between the management point marks are both 500 mm.

8. A method of controlling the accuracy of a bilge round-bulb line of an LNG ship according to any one of claims 1 to 7, characterized in that, After the step 4 is completed, the line type of the turning position of the bilge section is re-measured and recorded, the line type re-measured structure of the bilge section to be butt-jointed is compared, if the line types of the bilge sections to be butt-jointed are matched, the requirement is met, and if the line types of the bilge sections to be butt-jointed are not matched, the line type of the bilge section is corrected.

9. An LNG ship bottom section, characterized by The method according to claim 8 is used for controlling the turning line type accuracy of the bilge.

Images