A method for determining a bending direction of a ship profile

Abstract

The application belongs to the ship structure technical field and is a ship profile bending direction determination method. The rib line is set to the starboard, that is, the rib line corresponds to the mathematical XY coordinate system, the X axis is positive to the right, and the Y axis is positive upward. Through a program for extracting CAD multi-segment line point coordinates, the point coordinate data of the rib line from the first end point to the tail end point is obtained. The sequentially arranged point coordinate data and the mathematical three-point vector product calculation formula are arranged in EXECL to obtain the bending characteristics of the corresponding circular arc of each continuous three points. Greater than zero is counterclockwise, that is, outward bending; less than zero is clockwise, that is, inward bending. The ship profile bending direction determination method has simple steps, can cooperate with a three-point circular arc radius calculation program, accurately distinguishes the inward and outward bending of the non-bendable processing area of the batch point coordinate data, and is convenient for subsequent processing of the ship body structure, solves the problems of the prior art, and improves the shipbuilding process quality.

Description

Technical Field

[0001] This invention belongs to the field of ship structure technology, and more specifically, relates to a method for determining the bending direction of ship profiles. Background Technology

[0002] Ship structure, also known as "hull structure," refers to the collective term for ship hull structures composed of plates and frames. It mainly includes the bottom structure, side structure, deck structure, bulkhead structure, bow and stern structure, and superstructure. The main structural components of a ship are the primary supporting members of the hull, such as strong ribs, side longitudinal girder, strong transverse beams, deck longitudinal girder, solid ribs, bottom longitudinal girder, and bulkhead longitudinal girder. The web plates and face plates / stiffening plates of these main components are generally assembled from cut plates and are not affected by the curvature of the hull lines. Secondary components generally refer to the reinforcing members of the plates, such as ribs, longitudinal beams, transverse beams, bulkhead reinforcing members, and the skeleton of composite ribs. Secondary components are usually composed of hot-rolled profiles, such as bulb flats and unequal angle steel. For straight bulkhead reinforcing members and outer plate profiles in straight areas of the hull, no processing is required. For the midship area and areas with gentler curvature at the bow and stern, profile processing can proceed normally. For the outer plate ribs of the bulbotor region (see...) Figure 1 The longitudinal ribs on the side of the forepost plating area, the outer plating ribs at the engine room stern shaft outlet, and the outer plating ribs at the upward transition inward bend, etc., due to the large curvature of the profiles, and the limitation of steel shrinkage rate, may encounter problems with the bending process not being completed to the required extent. Generally, the minimum bending radius for rib bending machines is 10 times the height of the profile web (see...). Figure 2 Bending radii less than 10 times the height of the profile web usually need to be replaced by a composite structure of plates to achieve better construction convenience.

[0003] The drawback of existing technology is that the minimum bending radius processed by a typical rib bending machine is 10 times the profile web height. This usually refers to the profile being placed on the bending machine's workbench, where it can bend freely. That is, the profile can bend inwards (with the welded edge on the inside of the bend) or outwards (with the welded edge on the outside of the bend) along its web surface, with the minimum bending radius always being the inner side of the profile's bending arc (see Figure 3). However, the ball head of the profile (bulk flat steel) is always a free edge, meaning the non-ball head side is always welded tightly to the outer plate. If the bending radius of the profile is directly represented by the bending arc of the outer plate rib line, when the profile bends outwards, the radius of the arc (welded edge) on the non-ball head side must be larger than the radius of the inner side of the bending arc by a profile web height "B". This means the minimum bending arc radius of the outer plate rib line is 11 times the profile web height; otherwise, the profile cannot be bent to the correct position. This will affect the difficulty and quality of subsequent shipbuilding processing. Therefore, it is necessary to determine the bending direction of the profile and then take appropriate action based on the determination.

[0004] Existing technology includes a method for detecting the profile of a striped profile, published under number JPS5930009A. This method, for high-precision detection, obtains a baseline for the curved line by connecting the minimum points of the profile of the strip-shaped component, and identifies high points where the deviation between the reference line and the actual measured value exceeds the allowable value. The method involves an X-ray plate thickness gauge 12 that can move freely in the width direction of the steel strip 10 via a wheel 12a. A measuring device 14 detects the amount of movement of the X-ray plate thickness gauge 12 in the width direction. The detected and actual measured values ​​of the plate thickness at each point are inserted into an operating device 16. The operating device 16 sequentially scans the measured values ​​at each point in the width direction to determine the minimum points. Then, the minimum points are continuously connected to obtain the curved line. The deviation between the reference line and the actual measured value is obtained. Points with deviations exceeding the allowable value are identified as high points. The determination results of the operating device 16 are displayed on an oscilloscope 18 and printed by an XY plotter 20.

[0005] However, this technology does not address the technical issues and solutions of this application. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a simple method for determining the bending direction of ship profiles. This method can be used in conjunction with a three-point arc radius calculation program to accurately identify the inner and outer bending of the non-bendable arc processing area (combined with profile specifications) of batch point coordinate data (station lines / rib lines), thereby facilitating subsequent processing of the hull structure, solving the problems existing in the prior art, and improving the quality of shipbuilding process.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] This invention relates to a method for determining the bending direction of ship profiles. The determination steps of the method are as follows:

[0009] S1. Use the product of three points in a mathematical coordinate system to determine the direction of curvature of the arc passing through the three points. Before making the determination, define the starting point and the ending point, i.e.:

[0010] P1=(x1,y1), P2=(x2,y2), P3=(x3,y3),

[0011] Find vectors P12 = (x2 - x1, y2 - y1) and P23 = (x3 - x2, y3 - y2).

[0012] Then the cross product (vector product) of P12 and P23 is:

[0013] P12xP23=(x2-x1)*(y3-y2)-(y2-y1)*(x3-x2),

[0014] When the value is positive, the path of P1-P2-P3 is counterclockwise; when the value is negative, the path of P1-P2-P3 is clockwise; when the value is zero, the direction of P1-P2-P3 remains unchanged, that is, the three points are on a straight line.

[0015] S2. The rib line is uniformly set as starboard, that is, the rib line corresponds to the mathematical XY coordinate system, with the X-axis to the right being positive and the Y-axis upward being positive. By extracting the coordinates of the points of the CAD polyline, the coordinate data of each point from the bow end to the stern end of the rib line is obtained. These sequentially arranged point coordinate data and the mathematical three-point vector product calculation formula are arranged in EXECL to obtain the curvature characteristics of the arc corresponding to each consecutive three points. A value greater than zero indicates counterclockwise, i.e., outward curvature; a value less than zero indicates clockwise, i.e., inward curvature.

[0016] S3. Three-point arcs with a value greater than zero should be judged according to 11 times the profile web height, while three-point arcs with a value less than zero should be judged according to 10 times the profile web height.

[0017] In Excel, according to the mathematical formula for the cross product of vectors:

[0018] (P12xP23=(x2-x1)*(y3-y2)-(y2-y1)*(x3-x2)),

[0019] The coordinate data of continuous points (X and Y values) are placed on the left side of the calculation table. At the same time, the coordinate value of the second point is aligned with the calculation result rows on the right. That is, the "vector product" value corresponding to the point is the direction of the arc curvature at that point. A value greater than zero indicates counterclockwise curvature, i.e., outward curvature; a value less than zero indicates clockwise curvature, i.e., inward curvature.

[0020] Organize the station lines / rib lines using CAD software (uniformly on the starboard side). If represented by spline curves, they need to be converted into polylines. Use software or tools to extract the point coordinates of the polylines (station lines / rib lines) in CAD format to obtain point coordinate data. These data are sorted from bottom to top, that is, the Y values ​​are arranged in ascending order.

[0021] Input the coordinates of each station line / rib line point into the EXECL calculation program and the corresponding coordinates "X" and "Y" in the table below.

[0022] Based on the analysis of the vector product calculation results, a vector product greater than zero indicates counterclockwise rotation, i.e., outward bending.

[0023] Based on the analysis of the vector product calculation results, a vector product less than zero indicates clockwise rotation, i.e., an inward curve.

[0024] For three-point arc radii with a calculated vector product greater than zero, the radius should be determined based on 11 times the profile web height, while for three-point arc radii with a calculated vector product less than zero, the radius should be determined based on 10 times the profile web height.

[0025] When determining whether a profile can be bent and formed using the radius of curvature of the outer rib line, the above steps are used to determine whether the profile is bent inward or outward; when the profile is bent inward, the minimum radius of curvature of the rib line is R = 10B, and when the profile is bent outward, the minimum radius of curvature of the rib line is R = 11B.

[0026] The working principle and beneficial effects of the technical solution adopted in this invention are as follows:

[0027] The method for determining the bending direction of ship profiles described in this invention is simple in steps and reliable in judgment. When determining whether a profile can be bent and formed using the bending arc radius of the outer plate rib line, it is necessary to determine whether the profile is bent inward or outward. The above steps conveniently and quickly determine whether the profile is bent inward or outward. Then, based on the judgment result, the minimum radius of the rib line arc is selected. When the profile is bent inward, the minimum radius of the rib line arc is R = 10B; when the profile is bent outward, the minimum radius of the rib line arc is R = 11B. This facilitates the bending operation of the profile and ensures the quality of the ship hull processing. The method of this invention uses the reliable calculation method of the product of three consecutive points, and the program calculation is convenient and quick. It is beneficial for the analysis of the arc bending direction of batch point coordinates. Combined with the three-point arc radius calculation program, it can accurately distinguish between inward and outward bending of the arc non-bending processing area (combined with profile specifications) of batch point coordinate data (station line / rib line). Attached Figure Description

[0028] The following is a brief explanation of the contents depicted in the accompanying drawings and the markings therein:

[0029] Figure 1 This is a schematic diagram of the structure of the outer plate ribs in the bulbous bow region of the ship described in this invention;

[0030] Figure 2 The main technical parameters of the rib cold bending machine described in this invention are as follows:

[0031] Figure 3a This is a schematic diagram of the internal bending of the profile according to the present invention;

[0032] Figure 3b This is a schematic diagram of the internal bending of the profile according to the present invention;

[0033] Figure 3c This is a schematic diagram of the external bending of the profile according to the present invention;

[0034] Figure 3d This is a schematic diagram of the external bending of the profile according to the present invention;

[0035] Figure 4 This is a flowchart illustrating the process of determining the bending direction of the profile as described in this invention.

[0036] Figure 5This refers to the vector product data of the three-point circular arc of the profile described in this invention;

[0037] Figure 6 The rib line / station line point coordinate data of the profile described in this invention;

[0038] Figure 7 This is a vector product verification data diagram of the profile described in this invention;

[0039] The labels in the attached diagram are: 1. Inward curve of the ribs; 2. Outward curve of the ribs. Detailed Implementation

[0040] The following description, with reference to the accompanying drawings, provides a more detailed explanation of the specific embodiments of the present invention, including the shape and structure of each component, the relative positions and connections between the parts, the functions and working principles of each part:

[0041] As attached Figure 1 -Appendix Figure 7 As shown, this invention provides a method for determining the bending direction of ship profiles. The determination steps of this method are as follows:

[0042] S1. Use the product of three points in a mathematical coordinate system to determine the direction of curvature of the arc passing through the three points. Before making the determination, define the starting point and the ending point, i.e.:

[0043] P1=(x1,y1), P2=(x2,y2), P3=(x3,y3),

[0044] Find vectors P12 = (x2 - x1, y2 - y1) and P23 = (x3 - x2, y3 - y2).

[0045] Then the cross product (vector product) of P12 and P23 is:

[0046] P12xP23=(x2-x1)*(y3-y2)-(y2-y1)*(x3-x2),

[0047] When the value is positive, the path of P1-P2-P3 is counterclockwise; when the value is negative, the path of P1-P2-P3 is clockwise; when the value is zero, the direction of P1-P2-P3 remains unchanged, that is, the three points are on a straight line.

[0048] S2. The rib line is uniformly set as starboard, that is, the rib line corresponds to the mathematical XY coordinate system, with the X-axis to the right being positive and the Y-axis upward being positive. By extracting the coordinates of the points of the CAD polyline, the coordinate data of each point from the bow end to the stern end of the rib line is obtained. These sequentially arranged point coordinate data and the mathematical three-point vector product calculation formula are arranged in EXECL to obtain the curvature characteristics of the arc corresponding to each consecutive three points. A value greater than zero indicates counterclockwise, i.e., outward curvature; a value less than zero indicates clockwise, i.e., inward curvature.

[0049] S3. Three-point arcs with a value greater than zero should be judged according to 11 times the profile web height, while three-point arcs with a value less than zero should be judged according to 10 times the profile web height.

[0050] The above steps address the shortcomings of existing technologies and propose improved technical solutions. When determining whether a profile can be bent and formed using the bending arc radius of the outer plate rib line, it is necessary to determine whether the profile is bent inwards or outwards. The above steps facilitate a quick and easy determination of whether the profile is bent inwards or outwards. Based on the determination result, the minimum radius of the rib line arc is selected. When the profile is bent inwards, the minimum radius of the rib line arc is R = 10B; when the profile is bent outwards, the minimum radius of the rib line arc is R = 11B. This facilitates the bending operation of the profile and ensures the quality of the hull processing. The method of this invention utilizes a reliable calculation method based on the product of three consecutive points, and the program calculation is convenient and quick. It is beneficial for analyzing the arc bending direction of batch point coordinates. Combined with the three-point arc radius calculation program, it can accurately distinguish between inward and outward bending in areas of batch point coordinate data (station lines / rib lines) where the arc cannot be bent (in conjunction with profile specifications). The method for determining the bending direction of ship profiles described in this invention has simple steps and can be used in conjunction with a three-point arc radius calculation program to accurately distinguish between internal and external bends in the non-bendable arc processing area (combined with profile specifications) of batch point coordinate data (station lines / rib lines). This facilitates subsequent processing of the hull structure, solves the problems of existing technologies, and improves the quality of shipbuilding processes.

[0051] In Excel, according to the mathematical formula for the cross product of vectors:

[0052] (P12xP23=(x2-x1)*(y3-y2)-(y2-y1)*(x3-x2)),

[0053] The coordinates of continuous points (X and Y values) are placed on the left side of the calculation table. The coordinates of the second point are aligned with the rows of calculation results on the right. The "vector product" value corresponding to that point indicates the direction of the arc's curvature at that point: a value greater than zero indicates counter-clockwise (outward curve), and a value less than zero indicates clockwise (inward curve). See... Figure 5 .

[0054] Organize the station lines / rib lines using CAD software (uniformly based on the starboard side). If represented by spline curves, they need to be converted to polylines. Use software or tools to extract point coordinates from the CAD format polylines (station lines / rib lines) to obtain point coordinate data. This data is sorted from bottom to top, i.e., Y values ​​are arranged in ascending order. See... Figure 6 .

[0055] Input the coordinates of each station / rib line point into the EXECL calculation program; the corresponding "X" and "Y" coordinates are shown in the table below. See... Figure 5.

[0056] Based on the analysis of the vector product calculation results, a vector product greater than zero indicates counterclockwise rotation, i.e., outward bending.

[0057] Based on the analysis of the vector product calculation results, a vector product less than zero indicates clockwise rotation, i.e., an inward curve.

[0058] For three-point arc radii with a calculated vector product greater than zero, the radius should be determined based on 11 times the profile web height, while for three-point arc radii with a calculated vector product less than zero, the radius should be determined based on 10 times the profile web height.

[0059] When determining whether a profile can be bent and formed using the radius of curvature of the outer rib line, the above steps are used to determine whether the profile is bent inward or outward; when the profile is bent inward, the minimum radius of curvature of the rib line is R = 10B, and when the profile is bent outward, the minimum radius of curvature of the rib line is R = 11B.

[0060] The innovative aspects of the ship profile bending direction determination method described in this invention are: 1. Utilizing the properties of the product of three points in mathematics to determine the bending direction of an arc passing through three consecutive points; 2. Station lines / rib lines are uniformly adopted on the starboard side, corresponding to the mathematical XY coordinate system; 3. The coordinates of station lines / rib lines and the formula for the product of three points are edited in a table in "EXCEL" to facilitate batch processing of single station line / rib line coordinate point data, obtaining the arc bending direction at different positions of the station line / rib line; 4. The physical characteristics of station line / rib line bending are transformed into digital characteristics, facilitating combination with other determination programs for specific analysis, thus advancing shipbuilding process problems towards automatic computer program judgment. This method conveniently and quickly determines whether the profile is internally or externally bent, and then, based on the determination result, selects the minimum radius of the rib line arc. When the profile is internally bent, the minimum radius of the rib line arc is R = 10B; when the profile is externally bent, the minimum radius of the rib line arc is R = 11B. This facilitates the bending of the profiles, thereby ensuring the quality of the ship hull processing.

[0061] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A method for determining the bending direction of ship profiles, characterized in that: The determination steps of the method for determining the bending direction of ship profiles are as follows: S1. Use the product of three points in a mathematical coordinate system to determine the direction of curvature of the arc passing through the three points. Before making the determination, define the starting point and the ending point, i.e.: P1=(x1,y1), P2=(x2,y2), P3=(x3,y3), Find vectors P12=(x2-x1, y2-y1) and P23=(x3-x2, y3-y2). Then the vector product of P12 and P23 is: P12xP23=(x2-x1)*(y3-y2)-(y2-y1)*(x3-x2), When the value is positive, the path of P1-P2-P3 is counterclockwise; when the value is negative, the path of P1-P2-P3 is clockwise; when the value is zero, the direction of P1-P2-P3 remains unchanged, that is, the three points are on a straight line. S2. The rib line is uniformly set as starboard, that is, the rib line corresponds to the mathematical XY coordinate system, with the X-axis to the right being positive and the Y-axis upward being positive. By extracting the coordinates of the points of the CAD polyline, the coordinate data of each point from the bow end to the stern end of the rib line is obtained. These sequentially arranged point coordinate data and the mathematical three-point vector product calculation formula are arranged in EXECL to obtain the curvature characteristics of the arc corresponding to each three consecutive points. A value greater than zero indicates counterclockwise, that is, outward curvature. A value less than zero indicates clockwise rotation, i.e., an inward curve. S3. Three-point arcs with a value greater than zero are judged according to 11 times the profile web height, while three-point arcs with a value less than zero are judged according to 10 times the profile web height.

2. The method for determining the bending direction of ship profiles according to claim 1, characterized in that: In Excel, according to the mathematical formula for the cross product of vectors: (P12xP23=(x2-x1)*(y3-y2)-(y2-y1)*(x3-x2)), The coordinate data of continuous points (X and Y values) are placed on the left side of the calculation table. At the same time, the coordinate value of the second point is aligned with the calculation result rows on the right. That is, the "vector product" value corresponding to the point is the direction of the arc curvature at that point. A value greater than zero indicates counterclockwise curvature, i.e., outward curvature; a value less than zero indicates clockwise curvature, i.e., inward curvature.

3. The method for determining the bending direction of ship profiles according to claim 1 or 2, characterized in that: Use CAD software to organize station lines / rib lines. If the lines are represented by spline curves, they need to be converted into polylines. Use software or tools to extract point coordinates from the polylines in CAD format to obtain point coordinate data. These data are sorted from bottom to top, that is, the Y values ​​are arranged in ascending order.

4. The method for determining the bending direction of ship profiles according to claim 1 or 2, characterized in that: Input the coordinates of each station line / rib line point into the EXECL calculation program and the corresponding coordinates "X" and "Y" in the table below.

5. The method for determining the bending direction of ship profiles according to claim 1 or 2, characterized in that: Based on the analysis of the vector product calculation results, a vector product greater than zero indicates counterclockwise rotation, i.e., outward bending.

6. The method for determining the bending direction of ship profiles according to claim 5, characterized in that: Based on the analysis of the vector product calculation results, a vector product less than zero indicates clockwise rotation, i.e., an inward curve.

7. The method for determining the bending direction of ship profiles according to claim 1 or 2, characterized in that: For three-point arc radii with a calculated vector product greater than zero, the radius is determined by 11 times the profile web height; for three-point arc radii with a calculated vector product less than zero, the radius is determined by 10 times the profile web height.

8. The method for determining the bending direction of ship profiles according to claim 1 or 2, characterized in that: When determining whether a profile can be bent and formed using the bending radius of the outer rib line, the above steps are used to determine whether the profile is bent inward or outward; when the profile is bent inward, the minimum radius of the rib line arc is R=10B, and when the profile is bent outward, the minimum radius of the rib line arc is R=11B.

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