Ship block lifting lug arrangement method

Abstract

The invention discloses a ship block lifting lug arrangement method. The method comprises the following steps that S1, a lifting lug type structure adopted by a block body is determined; s2, determining the mounting position of a lifting lug of the segmented main body, and analyzing the mounting position of the lifting lug according to the gravity center position, the structural strength distribution and the lifting height of the segmented main body; s3, the hoisting strength of the segmented lifting lugs is determined, and the obtained hoisting strength result is compared with the shear resistance design strength of the selected steel to determine the specification and size of the lifting lugs; and S4, the installation requirement of the lifting lug is determined, specifically, the axis of a through hole of the lifting lug is arranged in the gravity center direction of the segmented body, the axis of the through hole and the stress direction of the sling are collinear, and the lifting lug and the segmented structure are connected in a full penetration weld joint mode. The problem that the safety of an existing segmented lifting lug cannot be guaranteed is solved.

Description

Technical Field

[0001] The invention relates to the field of technical ship hoisting, and in particular to a method for arranging ship segmented lifting lugs. Background Art

[0002] The 2200t multipurpose semi-submersible crane vessel is divided into 155 sections in total, which is a large number of sections compared with general conventional ships. The layout of the section lifting lugs, turning lugs and lifting lugs has the following difficulties: the ship section area is divided into the main sections of bow, midship and stern, as well as the sections built on the dock wall. In particular, the bow and stern have large changes in the lines, resulting in different section shapes and large changes in the layout of the lifting lugs with different rules. In addition, the limitations of the load size and lifting height of the lifting equipment make it difficult to guarantee the safety of section lifting or transportation. Summary of the Invention

[0003] In view of the above defects in the prior art, the present invention provides a method for arranging segmented lifting eyes of a ship to ensure the safety and stability of the segmented lifting eyes during the lifting process.

[0004] The present invention is achieved by adopting the following technical solutions: A method for laying out segmented lifting lugs for a ship comprises the following steps: Step S1, determining the lug type structure adopted by the segmented body; Step S2: Determine the installation position of the lifting lugs of the segmented body. The installation position of the lifting lugs is set according to the center of gravity, structural strength distribution and hoisting height of the segmented body so that the segmented body remains stable during the hoisting process. Step S3: Determine the lifting strength of the segmented lifting lugs, and compare the obtained lifting strength results with the shear design strength of the selected steel. If the lifting strength results are less than or equal to the shear design strength of the selected steel, the specifications and dimensions of the lifting lugs are selected to correspond to the shear design strength of the selected steel. If the lifting strength results are greater than the shear design strength of the selected steel, the specifications and dimensions of the lifting lugs are adjusted. The calculation formula for the lifting strength is: , In the formula, k is the dynamic load coefficient, is the compressive stress of the plate hole wall, P is the external force on the lug plate, δ is the plate hole wall thickness, d is the plate hole diameter, R is the effective radius of the lug plate outer edge, r is the plate hole radius, and [fᵥ] is the design value of the shear strength of the lug plate material; Step S4, determine the installation requirements of the lifting lug: the through hole axis of the lifting lug is set towards the center of gravity of the segmented body, and the through hole axis is collinear with the force direction of the sling, and the connection between the lifting lug and the segmented body adopts the form of full penetration weld.

[0005] Furthermore, in step S1 , the type and structure of the segmented lifting lugs are determined according to the construction method of the segmented body.

[0006] Furthermore, D-shaped lifting lugs are used when constructing the segmented main body using the positive construction method.

[0007] Furthermore, when the segmented main body is constructed using the inverted or horizontal construction method, the main turning lugs use B-type lifting lugs and the auxiliary lifting lugs use D-type lifting lugs.

[0008] Furthermore, in step S2, the installation position of the lifting lug must satisfy the following requirement: the line of action of the resultant force of the sling passes through the projection point of the center of gravity on the horizontal plane.

[0009] Furthermore, in step S2, The center of gravity position is determined by the following steps: Constructing a 3D digital model of the segmented body; Calculate theoretical center of gravity coordinates based on material density distribution; Check the center of gravity offset in combination with segmented manufacturing tolerances.

[0010] Furthermore, in step S2, the installation position of the lifting lug is set as a lifting point, and the distance L between two adjacent lifting points and the lifting height satisfy the functional relationship: ,in, is the angle between a single sling and the plumb line, and H is the vertical height from the lifting eye to the top surface of the segmented body.

[0011] Furthermore, in step S3, the external force P acting on the lifting lug plate is determined by the weight of the segmented body, the installation position of the lifting lug, and the angle between the lifting rope and the plumb line.

[0012] Furthermore, in step S3, the relationship between the weight of the segmented body and the tension S of a single sling is: , where Q is the weight of the segmented body, P is the tension borne by a single sling, It is the angle between a single sling and the plumb line.

[0013] Furthermore, in step S4, the horizontal heights of the lifting ears on the same plane are the same.

[0014] Furthermore, in step S4, the weld between the lifting lug and the segmented body is inspected by an ultrasonic flaw detector to determine whether the weld is qualified.

[0015] Compared with the prior art, the beneficial effects of the present invention include at least: The segmented lifting ears of the present invention can ensure the safety and stability of the segmented lifting ears during the lifting process through the control of selection, installation position, lifting strength and installation process, reduce safety hazards, ensure the installation quality of the segments, and can reasonably design the lifting ear layout according to the segmented bodies of different structures, with strong versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1is a schematic diagram of a D-shaped lifting lug according to an embodiment of the present invention; Figure 2 Schematic diagram of a B-type lifting lug according to an embodiment of the present invention; Figure 3 yes Figure 2 Cross-sectional view at MM; Figure 4 1 is a schematic diagram of the hoisting of a segmented body according to an embodiment of the present invention; Figure 5 is a force analysis diagram of the hoisting load of the sling according to an embodiment of the present invention; Figure 6 Schematic diagram showing the installation orientation of the lifting lugs and the line of action of the combined force of the lifting rope passing through the center of gravity of the segmented body according to an embodiment of the present invention; Figure 7 is a partial perspective view of the stern portion of an embodiment of the present invention; Figure 8 This is a perspective view of a partial section of the bow of an embodiment of the present invention; Figure 9 Schematic diagram of design strength index of steel according to an embodiment of the present invention; In the figure: 1. Lifting lug; 2. Segmented body; 3. Lifting rope; 4. Center of gravity. DETAILED DESCRIPTION

[0017] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concepts of the example embodiments to those skilled in the art. Identical reference numerals in the drawings represent identical or similar structures, and thus repeated descriptions thereof will be omitted.

[0018] The words expressing positions and directions described in the present invention are all explained with reference to the accompanying drawings as examples, but can be modified as needed, and all such modifications are within the scope of protection of the present invention.

[0019] like Figures 1 to 9 As shown, a method for laying out segmented lifting lugs for ships provided by the present invention comprises the following steps: Step S1, determining the type of lug 1 structure used by the segmented body 2; Step S2: determining the installation position of the lifting lug 1 of the segmented body 2. The installation position of the lifting lug 1 is set according to the center of gravity position 4 of the segmented body 2, the structural strength distribution, and the hoisting height, so that the segmented body 2 remains stable during the hoisting process. Step S3: Determine the lifting strength of the segmented lifting lug 1, and compare the obtained lifting strength result with the shear design strength of the selected steel. If the lifting strength result is less than or equal to the shear design strength of the selected steel, the size of the lifting lug 1 is selected to correspond to the shear design strength of the selected steel. If the lifting strength result is greater than the shear design strength of the selected steel, adjust the size of the lifting lug 1. The calculation formula for the lifting strength is: , In the formula, k is the dynamic load coefficient; is the compressive stress on the plate hole wall, P is the external force on the lug plate, is the plate hole wall thickness, d is the plate hole diameter, R is the effective radius of the lug plate outer edge, r is the plate hole radius, and [fᵥ] is the design value of the shear strength of the lug plate material; Step S4, determine the installation requirements of the segmented lifting lug 1: the through hole axis of the lifting lug 1 is set towards the center of gravity of the segmented body 2, and the through hole axis is collinear with the force direction of the sling 3, and the connection between the lifting lug 1 and the segmented body 2 adopts the form of full penetration weld.

[0020] In this embodiment, the ship sections are divided into four sections: the bow section, the midship section, the stern section and the dock wall section. Before laying out the lifting lug 1, the type and structure of the lifting lug 1 are determined first to ensure the safety and efficiency of the lifting process; after determining the type and structure of the lifting lug 1, the installation position of the lifting lug 1 is analyzed according to the center of gravity position, structural strength distribution and lifting height of the segmented body 2, so that the lifting lug 1 can be accurately laid out on the segmented body 2 to ensure stable lifting; after the lifting point position is determined, the lifting strength of the lifting lug 1 is determined. The lifting strength reflects the ability of the lifting lug 1 to resist damage. The lifting strength is compared with the shear design strength of the selected steel material, such as Figure 9 , the specifications and dimensions of the lifting eye 1 can be determined, thereby eliminating the risk of breakage caused by empirical selection; since the change in the direction of the lifting eye 1 will cause the lifting eye 1 to bear a sharp load, the through-hole axis of the lifting eye 1 is set towards the center of gravity of the segmented body 2, and the through-hole axis is collinear with the force direction of the sling 3. In this way, the tension of the sling 3 can be converted into a pure axial load and transmitted to the segmented body 2 to eliminate the lateral bending moment component. At the same time, the connection between the lifting eye 1 and the segmented structure adopts the form of full penetration welds to ensure the balance and stability of the segmented body 2 during the lifting process, avoid dangerous situations such as tilting, shaking or even flipping during the lifting process, and ensure the safety and smooth progress of the lifting operation.

[0021] The segmented lifting ear 1 of the present invention can ensure the safety and stability of the segmented lifting ear 1 during the lifting process through the control of selection, installation position, lifting strength and installation process, reduce safety hazards, ensure the installation quality of the segments, and can reasonably design the layout of the lifting ear 1 according to the segmented main body 2 with different structures, and has strong versatility. It should be noted that k is the dynamic load coefficient, and K in this embodiment is 1.1.

[0022] As a preferred embodiment, in step S1 , the type and structure of the segmented lifting lug 1 is determined according to the construction method of the segmented body 2 .

[0023] In this embodiment, due to different construction methods, differences in welding methods, material properties, process requirements, etc., the weight distribution, center of gravity position, shape characteristics, etc. of the segments will be different. Selecting the appropriate type of lifting lug 1 according to the specific construction method can ensure the safety and stability of the segments during the lifting process.

[0024] As a preferred embodiment, the segmented body 2 is constructed using a D-shaped lifting lug 1 when constructed using a positive construction method.

[0025] In this embodiment, the vertical construction method is a specific construction method for constructing the segmented body 2. Generally, the structure is constructed from the bottom up, starting with the foundation and gradually moving upwards, following the normal structural assembly sequence. The D-shaped lifting lug 1 is named because its shape resembles the letter "D." During the construction of the segmented body 2, when the segment needs to be lifted or moved, the D-shaped lifting lug 1 is used to connect the lifting equipment (such as a crane hook) to the segmented body 2 for safe and stable lifting.

[0026] As a preferred embodiment, when the segmented main body 2 is constructed using an inverted or horizontal installation method, the main turning over adopts a B-type lifting lug 1 and the auxiliary lifting lug 1 adopts a D-type lifting lug 1.

[0027] In this embodiment, when the segmented body 2 is turned over, the primary lifting and turning tasks are performed by the B-type lifting lugs 1. The B-type lifting lugs 1 possess sufficient strength and stability to withstand the primary weight and tension of the segmented body 2 during the turning process, ensuring a safe and stable turning process. The auxiliary lifting lugs 1 utilize D-type lifting lugs 1 to assist in positioning, balancing, and stabilizing the segmented body 2 during the turning process. These lugs, in conjunction with the B-type main lifting lugs 1, complete the turning operation of the segmented body 2, ensuring a safe and stable lifting and turning process.

[0028] As a preferred embodiment, in step S2, The center of gravity position 4 is determined by the following steps: Constructing a 3D digital model of the segmented body 2; Calculate theoretical center of gravity coordinates based on material density distribution; Check the center of gravity offset in combination with segmented manufacturing tolerances.

[0029] In this embodiment, professional 3D modeling software is used to construct an accurate 3D digital model of each segment based on the actual geometric shape, dimensions, and other information of the segmented body 2. After the 3D digital model is constructed, the theoretical center of gravity coordinates of the object are calculated by analyzing the material density distribution and applying relevant physical formulas and mathematical methods, as different materials may be used in different parts or the same material may be unevenly distributed in different locations. However, during the actual manufacturing process, due to factors such as the manufacturing process and processing accuracy, the actual size and shape of each segmented body 2 may deviate from the designed 3D digital model to a certain extent, namely, manufacturing tolerances. These deviations may cause the center of gravity position 4 of the object to shift. Therefore, it is necessary to verify the previously calculated theoretical center of gravity coordinates based on the manufacturing tolerances of the segments to determine the offset of the actual center of gravity from the theoretical center of gravity, thereby obtaining a center of gravity position 4 that is more consistent with the actual situation, thereby ensuring the precise placement of the lifting lugs 1 on the segmented body 2 and optimizing lifting stability.

[0030] As a preferred embodiment, in step S2, the installation position of the lifting lug 1 is set as a lifting point, and the distance L between two adjacent lifting points and the lifting height satisfy the functional relationship: ,in, is the angle between a single sling 3 and the plumb line, and H is the vertical height from the lifting eye 1 to the top surface of the segmented body 2.

[0031] In this embodiment, in order to ensure the safety and stability of the hoisting operation, the distance L between adjacent hoisting points and the hoisting height H are designed ( ) constraints, in actual operation, can be based on the lifting height H and the angle To reasonably set the distance between adjacent lifting ears 1.

[0032] As a preferred embodiment, in step S3, the external force P acting on the lifting lug plate is determined by the weight of the segmented body 2, the installation position of the lifting lug 1, and the angle between the lifting rope 3 and the plumb line.

[0033] In this embodiment, the installation position of the lifting lug 1 on the segmented body 2 affects the distribution and transmission path of force. Different installation positions cause the lifting lug plate to bear different forces. During lifting, the sling 3 forms a certain angle with the plumb line, which changes the vertical and horizontal components of the sling 3's tension, thereby affecting the load borne by the lifting lug 1. By comprehensively considering these three factors, the load borne by the segmented lifting lug 1 during lifting can be more accurately determined, ensuring the safety and reliability of the lifting operation.

[0034] As a preferred embodiment, in step S3, the relationship between the weight of the segmented body 2 and the tension S of a single sling 3 is: , where Q is the weight of the segmented body 2, P is the tension borne by a single sling 3, It is the angle between a single sling 3 and the plumb line.

[0035] In this embodiment, reference Figure 5 According to the relationship between the weight Q of the segmented body 2 and the tension P of the single sling 3, when Increase, decreases, S increases sharply, on the contrary, The tension S on a single sling 3 decreases. By constraining the weight of the segmented body 2 and the tension S on a single sling 3, the specifications and arrangement of the slings 3 can be reasonably determined to ensure safety and stability during the lifting process.

[0036] As a preferred embodiment, in step S4, the horizontal heights of the lifting ears 1 on the same plane are the same, so that the angle caused by the misalignment of the lifting ears 1 can be eliminated. Distortion ensures the calculation accuracy of the lifting strength, while ensuring that the shear force of each lifting lug 1 is evenly distributed to avoid local stress breaking through the critical line of fracture.

[0037] As a preferred embodiment, in step S4, the weld between the lifting lug 1 and the segmented body 2 is inspected with an ultrasonic flaw detector to determine whether the weld is qualified. By inspecting the weld to determine whether it is qualified, the reliability of the connection between the lifting lug 1 and the segmented body 2 is ensured, further improving the safety of the lifting operation.

[0038] It should be noted that the detection principle of ultrasonic flaw detectors is an existing technology and will not be described in detail here.

[0039] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limiting the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the invention without departing from the principles and purpose of the present invention. All such changes shall fall within the scope of protection of the claims of the present invention.

Claims

1. A method for laying out segmented lifting lugs for ships, characterized in that: The following steps are involved: Step S1, determining the type of lug (1) structure used by the segmented body (2); Step S2, determining the installation position of the lug (1) of the segmented body (2), wherein the installation position of the lug (1) is set based on the center of gravity position (4), the structural strength distribution and the hoisting height of the segmented body (2), so that the segmented body (2) remains stable during the hoisting process; Step S3, determine the lifting strength of the segmented lifting lug (1), compare the obtained lifting strength result with the shear design strength of the selected steel material, if the lifting strength result is less than or equal to the shear design strength of the selected steel material, then the specification size of the lifting lug (1) is selected to be the specification size corresponding to the shear design strength of the selected steel material, if the lifting strength result is greater than the shear design strength of the selected steel material, then adjust the specification size of the lifting lug (1), the calculation formula of the lifting strength is: , In the formula, k is the dynamic load coefficient, is the compressive stress on the plate hole wall, P is the external force on the lug plate, is the plate hole wall thickness, d is the plate hole diameter, R is the effective radius of the lug plate outer edge, and r is the plate hole radius; is the design value of shear strength of the lug plate material; Step S4, determining the installation requirements of the lifting lug (1): the through hole axis of the lifting lug (1) is arranged toward the center of gravity of the segmented body (2), and the through hole axis is collinear with the force direction of the sling (3), and the connection between the lifting lug (1) and the segmented body (2) adopts the form of a full penetration weld.

2. The method for laying out the ship segmented lifting lugs according to claim 1, characterized in that: In step S1, the type structure of the segmented lifting lug (1) is determined according to the construction method of the segmented body (2).

3. The method for laying out the ship segmented lifting lugs according to claim 2, characterized in that: The segmented main body (2) is constructed using a D-shaped lifting lug (1) when the vertical construction method is used.

4. The method for laying out segmented lifting lugs for ships according to claim 2, characterized in that: When the segmented main body (2) is constructed by an inverted or horizontal installation method, the main turning over adopts a B-type lifting lug (1), and the auxiliary lifting lug (1) adopts a D-type lifting lug (1).

5. The method for laying out segmented lifting lugs for ships according to claim 1, characterized in that: In step S2, The center of gravity position (4) is determined by the following steps: Constructing a 3D digital model of the segmented body (2); Calculate theoretical center of gravity coordinates based on material density distribution; Check the center of gravity offset in combination with segmented manufacturing tolerances.

6. The method for laying out segmented lifting lugs for ships according to claim 1, characterized in that: In step S2, the installation position of the lifting lug (1) is set as a lifting point, and the distance L between two adjacent lifting points and the lifting height satisfy the functional relationship: ,in, is the angle between a single sling (3) and the plumb line, and H is the vertical height from the lifting lug (1) to the top surface of the segmented body (2).

7. The method for laying out segmented lifting lugs for ships according to claim 1, characterized in that: In step S3, the external force P applied to the lug plate is determined based on the weight of the segmented body (2), the installation position of the lug (1), and the angle between the sling (3) and the plumb line.

8. The method for laying out segmented lifting lugs for ships according to claim 7, characterized in that: In step S3, the relationship between the weight of the segmented body (2) and the tension S of the single sling (3) is: , where Q is the weight of the segmented body (2), S is the tension borne by a single sling (3), It is the angle between a single sling (3) and the plumb line.

9. The method for laying out segmented lifting lugs for ships according to claim 1, characterized in that: In step S4, the horizontal heights of the lifting lugs (1) on the same plane are the same.

10. The method for laying out segmented lifting lugs for ships according to claim 1, characterized in that: In step S4, the weld between the lifting lug (1) and the segmented body (2) is detected by an ultrasonic flaw detector to determine whether the weld is qualified.

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