A lofting method for a bow side thrust hole of a ship outer plate

Abstract

A hull plating bow side thrust hole lofting method is disclosed, which designs the structure cylinder and trumpet mouth of the hull bow side thrust. The bow side thrust structure is generally divided into three parts: the side thrust cylinder body connected with the bow side thrust equipment, the flow guide groove and the trumpet mouth. According to the linear type and the type value of the curved surface plate, it is obtained that the welding surface of the bow side thrust cylinder body and the trumpet mouth is a plane A, another plane B parallel to the plane A is obtained according to the angle of the trumpet mouth extending outward, and a conical surface is formed by the two planes. In the normal plane, the two curved surfaces are considered as approximate straight lines, the curved surface is unfolded to give a processing template for processing. According to the hull plate linear type, the intersection line with the curved surface, that is, the actual material line of the trumpet mouth and the hull plate, is obtained, and the trumpet mouth is assembled in sections, and then the actual situation is cut and bevel welded according to the actual situation. The method can improve the lofting efficiency of the water droplet-shaped bow side thrust hole structure, reduce the processing difficulty and improve the assembly precision.

Description

Technical Field

[0001] This invention belongs to the field of shipbuilding and design, and specifically relates to a method for laying out the bow thrust holes of a ship's outer plating. Background Technology

[0002] With economic globalization and the booming development of world trade, the shipping industry has also continued to grow. As the volume and density of ships in ports gradually increase, higher demands are placed on the maneuverability and maneuverability of ships in order to improve navigation efficiency. The emergence of bow thrusters has provided a preliminary solution to this problem. Many large ships are equipped with auxiliary propulsion devices such as bow thrusters. The bow thruster is the device installed at the bow. When maneuvering in a port, the bow thruster can be used to facilitate turning and lateral displacement at low speeds. At the same time, when these ships are sailing at low speeds in restricted waters, the bow thruster can also be used to overcome the "bank effect" and "ship-to-ship effect".

[0003] In production design, based on the form data provided by the detailed design company for the bow thruster opening, and combined with the outer plating lines of the actual ship in the production design, a smooth transition needs to be made at the connection points between the flare and the guide channel and the outer plating. This minimizes the drag caused by the roughness of the hull surface due to the installation of the bow thruster. Simultaneously, during the lofting process, optimization of the lofting method, such as the selection of the flare surface curvature and the addition of breaks, reduces the difficulty of plate processing, thereby improving the accuracy of the machined parts and reducing the workload of subsequent on-site fitting. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for laying out the bow thrust hole on the outer plating of a ship. The aim is to achieve a smooth and fluid profile at the connection between the barrel and the outer plating at the bow thrust hole, as well as a smooth guide groove at the tail of the thrust hole aligned with the water flow direction. This effectively reduces resistance caused by turbulence and cavitation. The technical solution employed is as follows:

[0005] A method for laying out a bow thrust hole on a ship's outer plate. The bow thrust consists of a cylinder, a bell mouth, and a guide groove. The cylinder is connected to the ship's outer plate through the bell mouth. One end of the guide groove is smoothly connected to the bell mouth, and the width of the guide groove gradually decreases from the end connected to the bell mouth to the other end.

[0006] The procedure for determining the layout of the cylinder body and bell mouth at the opening in the ship's outer plating is as follows:

[0007] S1: Determine the range of the bow thruster opening on the ship's outer plating. Determine the center position of the bow thruster based on its arrangement. Determine the barrel diameter based on the equipment drawings. Then, based on the shape data of the barrel and bell mouth connection given in the bow thruster opening profile drawing, determine the intersection line A of the barrel and bell mouth connection. Define the inclined plane containing the intersection line A as plane A.

[0008] Among them, the shape data are the half-width values ​​at the bow and stern openings of the cylinder and the height values ​​from the baseline.

[0009] S2: Divide the cylinder containing the hull into 24 equal parts, and define a plane every 15 degrees. This plane is the normal plane for each angle. Then, according to the angle of the flared mouth expanding outward, draw extension lines in each normal plane. Determine a plane B parallel to plane A outside the outer plate of the hull. Cut plane B through each normal plane. Find the intersection line between each normal plane and plane B on plane B. Then find the intersection point of this intersection line and the extension line of the flared mouth on the corresponding normal plane. Smoothly connect each intersection point in plane B. This is the intersection line B of the flared mouth extension and the intersection line with plane B.

[0010] S3: When intersection lines A and B are connected, they form a conical surface, which is the surface where the flared end is located. Each normal surface intersects with intersection lines A and B respectively. The intersection point formed by intersection line A and the normal surface corresponds to the intersection point formed by intersection line B and the normal surface. The line connecting the corresponding intersection points is regarded as a straight line.

[0011] S4: Within the range of the bow-side push-opening hole, the waterline and rib line are densified. The densified waterline and rib line are obtained by calculating the difference between the waterline and rib line values ​​of the outer panel. Then, the intersection points of the densified waterline and rib line within the range and the corresponding normal surface are obtained. After these intersection points are smoothly connected in sequence, they become the solid material line connecting the flared mouth and the outer panel.

[0012] S5: Divide the flared mouth into multiple plates for assembly, avoiding the internal reinforcement structure position when making cuts. Using intersection line A and intersection line B as the inner and outer boundaries, determine the neutral axis according to the plate thickness and then lay out and unfold. Mark the normal line, solid line, internal reinforcement structure line and the position lines of the upper and lower bow and stern on each plate.

[0013] The intersection line A between the cylinder body and the flared mouth is a solid material. Welding nodes are set and bevels are opened. The bevels are full-penetration bevels. Each plate is processed according to the inner and outer processing templates of the intersection line A and the intersection line B. A processing allowance is added on the side of the intersection line B. A processing allowance is added at the break point of each plate.

[0014] After the opening layout of the cylinder body and the bell mouth is determined, the layout of the guide channel is based on the line shape given in the bow side push opening line shape diagram. First, the angle between the center line and the waterline is determined. On the longitudinal section, the guide channel is approximately divided into two equal parts on both sides according to the center line to obtain the dense auxiliary line. The plane where the auxiliary line is located is the guide channel auxiliary surface.

[0015] Then, using the lines of each rib of the guide channel given in the bow thrust opening line shape diagram as a reference, the intersection points are obtained by cutting through the guide channel auxiliary surface and the rib surface. These intersection points are the points on the curved surface where the guide channel is located. After smoothing these intersection points on the guide channel auxiliary surface and the rib surface, the curved surface of the guide channel can be obtained.

[0016] Finally, the curved surface of the guide channel is used to cut the conical surface where the horn mouth is located to obtain the intersection line, ensuring a smooth transition between the guide channel and the horn mouth.

[0017] Finally, the overall layout of the bow thrust hole was completed.

[0018] In a further step, the above-mentioned method for laying out the bow thrust hole on the outer plate of a ship is to make the cylinder body a cylindrical body processed from steel plate rolls, mark the upper and lower position lines of the bow and stern on the cylinder body, and add a machining allowance of 80mm on each side at the cut position.

[0019] In a further step, the above-mentioned method for laying out the bow side push hole of the ship's outer plate includes an additional machining allowance of 100mm on the side of the intersection line B for each plate in step S5, and an additional machining allowance of 80mm at the break point for each plate.

[0020] Furthermore, in the above-mentioned method for laying out the bow thrust hole on the outer plate of a ship, the guide channel is shaped like a water droplet.

[0021] Furthermore, when multiple bow thrusters need to be installed on the ship's outer plate, a guide channel is provided between the multiple bow thrusters, and the two ends of the guide channel are smoothly connected to the bow thrusters.

[0022] The above-mentioned method for laying out the bow thrust hole of a ship's outer plate is further improved by dividing the flared mouth into three plates for assembly in S5.

[0023] The beneficial effects of this invention are: the smooth and fluid lines at the connection between the bow-side thrust cylinder and the outer plate, and the smoothness of the guide groove at the tail of the thrust hole following the water flow direction, can effectively reduce the resistance caused by turbulence and cavitation. This improves the layout efficiency of this teardrop-shaped bow-side thrust hole structure, reduces processing difficulty, and improves assembly accuracy. Attached Figure Description

[0024] Figure 1 This is a side view schematic diagram of the bow-side thrust line type of the present invention;

[0025] Figure 2 This is a schematic diagram of the normal plane of the present invention divided into 24 equal parts;

[0026] Figure 3 These are schematic diagrams of plane A and plane B of the present invention;

[0027] Figure 4This is a schematic diagram of the intersection line A, intersection line B, and actual material line of the present invention;

[0028] Figure 5 This is a schematic diagram of the center line of the guide channel and the encryption auxiliary structure line of the present invention;

[0029] Figure 6 This is a schematic diagram of the connection structure between the barrel of the bow thruster of the present invention and the outer plate of the ship;

[0030] Figure 7 This is a schematic diagram of the connection structure between the barrel, guide channel, flare, and ship outer plate of the bow thruster of the present invention;

[0031] Figure 8 This is a schematic diagram of the extension line of the bow-side thrust flare of the present invention within the normal plane;

[0032] Among them, 1-guide channel, 2-ship outer plate, 3-flare mouth, 4-cylinder, 5-plane A, 6-plane B, 7-normal plane, 8-intersection line of plane B and each normal plane, 9-center line of guide channel, 10-densification auxiliary line. Detailed Implementation

[0033] The invention will be further described with reference to the accompanying drawings.

[0034] A method for laying out thrust holes on the bow side of a ship's outer plating, such as... Figure 1 , 6 As shown, the bow thruster consists of a barrel 4, a bell mouth 3, and a guide channel 1. The barrel is connected to the outer plate 2 of the ship through the bell mouth.

[0035] like Figure 7 As shown, there are two bow thrusters, arranged at different heights at the bow and stern. The openings of the bow thrusters on the ship's outer plating need to be laid out. The center of bow thruster NO.1 is located at FR234, 3000mm from the baseline; the center of bow thruster NO.2 is located at FR230, 2500mm from the baseline. The angle between the line connecting the centers of the two thrusters and the horizontal baseline is 11 degrees. Since there are two thruster holes, the structure at the thruster hole location includes not only the barrel, the stern guide channel, and the bell-shaped opening connecting the barrel and the outer plating, but also the guide channel between the two thruster holes.

[0036] The opening layout of bow thrusters No. 1 and No. 2 was carried out sequentially, and the specific layout method is as follows:

[0037] The extent of the bow thruster opening is determined on the ship's outer plating. The center position of the bow thruster is determined based on its arrangement. The barrel diameter is determined to be 1903 mm according to the equipment drawings. Then, the shape data of the barrel-to-bell connection point given in the bow thruster opening profile drawing is used, such as... Figure 1As shown, the intersection line A at the connection between the cylinder body and the flared mouth is determined, and the inclined plane where the intersection line A is located is defined as plane A5.

[0038] Among them, the shape data are the half-width values ​​at the bow and stern openings of the cylinder and the height values ​​from the baseline.

[0039] Based on the width values ​​at three and a half points and the height values ​​from the baseline at four positions (bow and stern) where each thruster's bellhead connects to the fuselage, given in the bow thruster's opening profile diagram, the inclined plane containing the intersection line A can be determined; this is plane A. Plane A for each thruster is independent and determined based on its respective profile values.

[0040] Define normal planes by dividing each thruster section into 24 equal parts. Define a plane every 15 degrees, which is normal plane 7. Based on the bow thruster opening profile diagram, the outward extension angle of the bell mouth in each section is 30 degrees. According to this condition, within each normal plane, draw an extension line extending outward at 30 degrees, as shown below. Figure 8 As shown.

[0041] like Figure 2-5 As shown, based on the outer panel profile, plane B6 is determined at a position 270mm from plane A of side pusher NO.1. This plane must be outside the outer panel, and the minimum distance between the lines connecting the intersection points of planes A and B on each normal surface should exceed the outer panel by approximately 100mm; this distance should not be too large to avoid material waste. Similarly, plane B is determined at a position 250mm from side pusher NO.2. The conical surface determined by planes A and B is the curved surface where the flared opening is located. Plane B is sectioned through each normal surface, and the intersection lines between each normal surface and plane B are determined. Then, the intersection point of this intersection line with the extended line of the flared opening on the corresponding normal surface is obtained. Smoothly connecting these intersection points on plane B sequentially yields the intersection line B, which is the line of intersection where the flared opening extends and intersects plane B.

[0042] Add half-rib lines between FR225 and FR236, and add water lines every 250mm between 1000mm and 4500mm. Calculate the intersection of the densified rib and water line surfaces with the conical surface of the flared end. After smooth connection, this becomes the solid material line connecting to the outer plate. When laying out the flared end plate, assemble it as three pieces. Because the material is cut to size at intersection A, determine the bevel angle according to the welding joints within each normal surface. Mark the normal lines, upper and lower bow / stern position lines, internal reinforcement structure lines, solid material lines, and the bevel angle at intersection A on the laid-out plate parts. Also, add machining allowances.

[0043] The layout of the guide channels includes the fan-shaped guide channel at the stern of the NO.2 side thruster and the guide channel between the two side thrusters. On the longitudinal section, the guide channels are approximately divided into two equal parts based on the centerline, resulting in auxiliary lines for reinforcement. The plane containing these auxiliary lines is the auxiliary surface. Intersections are obtained by cutting through the auxiliary surface and the rib surface. These intersections are the points on the curved surface where the guide channels are located. After smoothing these intersections in three directions on the auxiliary surface and the rib surface, the curved surface of the guide channels can be obtained. The intersection line between the curved surface of the guide channels and the curved surfaces of the two side thrusters is determined. Based on the line shape given in the bow side thruster opening line shape diagram, the intersection line position needs to be smoothed in three directions to ensure a smooth transition between the guide channels and the bell mouth. The cylinder body is laid out according to the cylinder shape with the intersection line A as the boundary. It is formed by rolling steel plates, avoiding the internal reinforcing structure at the cut position, and adding an 80mm machining allowance.

[0044] The present invention features a smooth and fluid profile at the connection between the bow thruster body and the outer plate, as well as a smooth guide groove at the tail of the thruster hole following the water flow direction. This effectively reduces the resistance caused by turbulence and cavitation. It also improves the layout efficiency of this teardrop-shaped bow thruster hole structure, reduces processing difficulty, and enhances assembly accuracy.

Claims

1. A method for laying out thrust holes on the bow side of a ship's outer plating, characterized in that, The bow thruster consists of a barrel, a bell mouth, and a guide channel. The barrel is connected to the ship's outer plate through the bell mouth. One end of the guide channel is smoothly connected to the bell mouth, and the width of the guide channel gradually decreases from the end connected to the bell mouth to the other end. The procedure for determining the layout of the cylinder body and bell mouth at the opening in the ship's outer plating is as follows: S1: Determine the range of the bow thruster opening on the ship's outer plating. Determine the center position of the bow thruster based on its arrangement. Determine the barrel diameter based on the equipment drawings. Then, based on the shape data of the barrel and bell mouth connection given in the bow thruster opening profile drawing, determine the intersection line A of the barrel and bell mouth connection. Define the inclined plane containing the intersection line A as plane A. Among them, the shape value data are the half-width values ​​at the upper and lower bow and stern openings of the cylinder and the height value from the baseline; S2: Divide the cylinder containing the hull into 24 equal parts, and define a plane every 15 degrees. This plane is the normal plane for each angle. Then, according to the angle of the flared mouth expanding outward, draw the extension line in each normal plane. Determine a plane B parallel to plane A outside the outer plate of the ship's body. Cut plane B through each normal plane. Find the intersection line between each normal plane and plane B on plane B. Then find the intersection point of this intersection line and the flared mouth extension line on the corresponding normal plane. Smoothly connect each intersection point in plane B. This is the intersection line B of the flared mouth extension and the intersection line with plane B. S3: When intersection lines A and B are connected, they form a cone surface, which is the surface where the bell mouth is located. Each normal surface has an intersection point with intersection lines A and B. The intersection point formed by intersection line A and the normal surface corresponds to the intersection point formed by intersection line B and the normal surface. The line connecting the corresponding intersection points is regarded as a straight line. S4: Within the range of the bow-side push-opening hole, the waterline and rib line are densified. The densified waterline and rib line are obtained by calculating the difference between the waterline and rib line type values ​​of the outer panel. Then, the intersection points of the densified waterline and rib line within the range and the corresponding normal surface are obtained. After these intersection points are smoothly connected in sequence, they become the solid material line connecting the flared mouth and the outer panel. S5: Divide the flared mouth into multiple plates for assembly, avoiding the internal reinforcement structure position when making cuts, with intersection line A and intersection line B as the inner and outer boundaries, and after determining the neutral axis according to the plate thickness, lay out and unfold. Mark the normal line, solid line, internal reinforcement structure line and the position lines of the upper and lower bow and stern on each plate. The intersection line A between the cylinder body and the flared mouth is a solid material. Welding nodes are set and bevels are opened. The bevels are full penetration bevels. Each plate is processed according to the inner and outer processing templates of the intersection line A and the intersection line B. A processing allowance is added on the side of the intersection line B. A processing allowance is added at the break point of each plate. After the opening layout of the cylinder body and the bell mouth is determined, the layout of the guide channel is based on the line shape given in the bow side push opening line shape diagram. First, the angle between the center line and the waterline is determined. On the longitudinal section, the guide channel is approximately divided into two equal parts on both sides according to the center line to obtain the dense auxiliary line. The plane where the auxiliary line is located is the guide channel auxiliary surface. Then, based on the lines of each rib of the guide channel given in the bow thrust opening line diagram, the intersection points are obtained by cutting through the guide channel auxiliary surface and the rib surface. These intersection points are the points on the curved surface where the guide channel is located. After smoothing these intersection points on the guide channel auxiliary surface and the rib surface, the curved surface of the guide channel can be obtained. Finally, the curved surface of the guide channel is used to cut the conical surface where the horn mouth is located to obtain the intersection line, ensuring a smooth transition between the guide channel and the horn mouth. Finally, the overall layout of the bow thrust hole was completed.

2. The method for laying out the bow thrust hole of a ship's outer plating according to claim 1, characterized in that, The cylinder body is cylindrical and is processed from rolled steel plate. The bow and stern position lines are marked on the cylinder. A machining allowance of 80mm needs to be added to each side at the cut position.

3. The method for laying out the bow thrust hole of a ship's outer plating according to claim 1, characterized in that, In step S5, each board has an additional machining allowance of 100mm on one side of the intersection line B, and each board has an additional machining allowance of 80mm at the break point.

4. The method for laying out the bow thrust hole of a ship's outer plating according to claim 1, characterized in that, The guide channel is shaped like a water droplet.

5. The method for laying out the bow thrust hole of a ship's outer plating according to claim 1, characterized in that, When multiple bow thrusters need to be installed on the outer plating of a ship, a flow channel is provided between the multiple bow thrusters, and the two ends of the flow channel are smoothly connected to the bow thrusters.

6. The method for laying out the bow thrust hole of a ship's outer plating according to claim 1, characterized in that, In the S5, the horn opening is assembled by dividing it into three plates.

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