A method for monitoring the lightweight design of an LNG ship structure

Abstract

The application discloses a kind of for LNG ship structure light weight design monitoring method, and the method specifically includes the following steps: S1, the composition of design stage in ship design life cycle is clear, the factor of influencing ship light weight in each stage is analyzed;S2, the light weight of ship is calculated by empirical formula in preliminary design stage;S3, in detail design stage, the ship weight gravity of different regions is clear detailed;S4, according to the ship weight gravity of different regions that is clear detailed, optimize ship structure form and equipment pedestal and reinforcement;S5, production design stage, according to integrated whole ship model information, the light weight design is carried out to ship equipment pedestal and reinforcement;S6, completion design stage, the weight change of each part of ship in different stage is checked.The application solves the problems of ship weight information not comprehensive, ship structure design extensive, and ship design weight not controlled by finite element analysis and reducing structure redundancy in different stages of ship design.

Description

Technical Field

[0001] This invention belongs to the field of shipbuilding technology, specifically relating to a monitoring method for lightweight structural design of LNG ships. Background Technology

[0002] With the growing international demand for energy conservation and emission reduction, lightweight technology, as one of the internationally recognized energy conservation and emission reduction technologies in the maritime community, helps reduce energy and resource consumption and lower shipbuilding costs. Ships equipped with lightweight technology can optimize various maneuvering performances during navigation, increase ship speed, achieve the goal of reducing fuel consumption under the same power conditions, and effectively improve the overall economic performance of the ship.

[0003] Lightweight hull is a crucial indicator for evaluating ship design, encompassing hull steel, timberwork and outfitting, electromechanical components, and specialized equipment such as anti-roll fins and vibration damping devices. For LNG carriers, hull steel accounts for approximately 65%-70% of the total weight, representing about 10.3% of the total cost. Therefore, hull structural weight is a major component of lightweight hull weight; controlling hull steel weight essentially controls the overall design weight. In conclusion, lightweighting the hull structure is the primary task in ship lightweighting.

[0004] Ship design cycles typically last for months or even years. During the design process, the structural weight can change due to various factors, and these changes generally show an upward trend. Therefore, managing the structural weight throughout the entire design lifecycle is of paramount importance. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for monitoring the lightweight design of LNG ship structures. This invention solves the problems of insufficient weight information, rough ship structural design, lack of means to control ship design weight, and uncontrolled ship design weight by using finite element analysis and reducing structural redundancy at different stages of ship design.

[0006] To achieve the above-mentioned objectives, the technical solution provided by this invention patent is as follows:

[0007] A monitoring method for lightweight structural design of LNG ships, the method specifically includes the following steps:

[0008] S1 clarifies the composition of the design phases within the ship design lifecycle, which includes the preliminary design phase, detailed design phase, production design phase, and final design phase, and analyzes the factors affecting the ship's lightship weight in each phase.

[0009] S2, Preliminary design phase, calculating the empty weight of the ship using empirical formulas;

[0010] S3, Detailed Design Stage: Based on the empty ship weight calculated in S2 and the ship design software, the full ship model information is integrated to clarify the ship weight center details in different areas.

[0011] S4. Based on the detailed information on the ship's weight center of gravity in different regions, optimize the hull structure and the equipment base and reinforcement scheme.

[0012] S5, Production Design Stage: Based on the integrated full-ship model information, reduce the various allowance values ​​for ship sections and carry out lightweight design for ship equipment bases and reinforcements.

[0013] S6, the final design stage, is based on domestically produced ship design software and relies on the ship model information completed at each stage. The weight information of each part of the hull in different stages is extracted and compared with the relevant areas of the hull in different stages to check the weight changes of each part of the ship at different stages. When the weight of each part of the ship at different stages does not meet the design requirements, the hull structure and equipment base are re-optimized and strengthened in the detailed design stage until the design requirements are met.

[0014] Furthermore, the factors affecting the empty weight of a ship specifically include: equipment selection in the preliminary design stage, plate thickness selection in the detailed design stage, and design reinforcement arrangements in the production design stage.

[0015] Furthermore, the calculation of the ship's empty weight in S2 is specifically as follows:

[0016] WH=k*L*B*D+C

[0017] Where WH is the weight of hull steel in tons; k is the hull steel weight coefficient; C is the regression coefficient; L is the ship length; B is the ship breadth; and D is the ship depth.

[0018] Furthermore, the ship design software is SPD, and the ship design software integrates the whole ship model information including the bow area, cargo hold area, engine room area, stern area and superstructure area. The ship weight and center of gravity details of different areas include outputting the weight and center of gravity information of the cargo hold area, the engine room area, the bow and stern areas, the superstructure, the bulwark, and the funnel.

[0019] Furthermore, the hull structure includes large openings in the main structure, and the equipment reinforcement includes ship equipment bases and reinforcement forms. The large openings in the main structure include large openings in the chimney, large openings in the hoisting opening, and large openings in the engine room. The ship equipment bases and reinforcements include generator bases and deck crane bases. By performing finite element analysis on the hull structure and ship equipment bases and reinforcement forms, the location and size of the large openings in the structure are optimized, and the redundancy of the hull structure and ship equipment bases and reinforcements is obtained. When there is redundancy in the hull structure, the plate thickness at the corresponding location of the hull is reduced.

[0020] Furthermore, the reduction of various allowance values ​​for ship sections is achieved by setting the ship section mounting to a zero-allowance docking, thereby reducing the weight of the ship sections. The lightweight design of the ship equipment base and reinforcement specifically involves reducing the use of permanent tooling for fixing the ship equipment base.

[0021] Furthermore, the extraction of weight information for various parts of the hull in different stages includes weight information for the bow region, cargo hold region, engine room region, stern region, and superstructure region. The weight changes of various parts of the hull in the detailed design stage and the production design stage are compared to ensure that the weight of various parts of the hull changes in an orderly manner in each stage.

[0022] Based on the above technical solution, the monitoring method for lightweight structural design of LNG ships, as proposed in this invention, has achieved the following technical advantages through practical application:

[0023] 1. The present invention provides a method for monitoring lightweight design of LNG ship structures. By using finite element analysis and reducing structural redundancy at different stages of ship design, this method addresses the problems of insufficient weight information, rough structural design, lack of means to control ship design weight, and uncontrolled ship design weight. Attached Figure Description

[0024] Figure 1 This is a flowchart of a lightweight design monitoring method for LNG ship structures, as described in this invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific examples shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0026] like Figure 1 As shown, this invention pertains to a monitoring method for lightweight structural design of LNG ships, and the method specifically includes the following steps:

[0027] S1 clarifies the composition of the design phases within the ship design lifecycle, which includes the preliminary design phase, detailed design phase, production design phase, and final design phase, and analyzes the factors affecting the ship's lightship weight in each phase.

[0028] S2, Preliminary design phase, calculating the empty weight of the ship using empirical formulas;

[0029] S3, Detailed Design Stage: Based on the empty ship weight calculated in S2 and the ship design software, the full ship model information is integrated to clarify the ship weight center details in different areas.

[0030] S4. Based on the detailed information on the ship's weight center of gravity in different regions, optimize the hull structure and the equipment base and reinforcement scheme.

[0031] S5, Production Design Stage: Based on the integrated full-ship model information, reduce the various allowance values ​​for ship sections and carry out lightweight design for ship equipment bases and reinforcements.

[0032] S6, the final design stage, is based on domestically produced ship design software and relies on the ship model information completed at each stage. The weight information of each part of the hull in different stages is extracted and compared with the relevant areas of the hull in different stages to check the weight changes of each part of the ship at different stages. When the weight of each part of the ship at different stages does not meet the design requirements, the hull structure and equipment base are re-optimized and strengthened in the detailed design stage until the design requirements are met.

[0033] From the detailed design stage to the production design stage and then to the final design stage, from a weight perspective alone, it is basically an increase on the original structural design, that is, an incremental weight process. This incremental process covers the detailed design stage at different times, structural safety assessment and other calculations, and the reinforcement of equipment openings under the coordination of relevant professionals. The results of these designs are directly reflected in the structure as a gradual increase in weight.

[0034] From the preliminary design stage to the detailed design stage and even the production design stage, the progress of each design stage is mostly additive, and various factors will cause weight increases; therefore, the lightweighting of ship structures requires a series of measures such as process monitoring and structural optimization at each stage.

[0035] The factors affecting the empty weight of a ship are specifically: equipment selection in the preliminary design stage, plate thickness selection in the detailed design stage, and design reinforcement arrangements in the production design stage.

[0036] The calculation of the empty ship weight in S2 is as follows:

[0037] WH=k*L*B*D+C

[0038] Where WH is the weight of hull steel in tons; k is the hull steel weight coefficient; C is the regression coefficient; L is the ship length; B is the ship breadth; and D is the ship depth.

[0039] The ship design software is SPD. The ship design software integrates the whole ship model information, including the bow area, cargo hold area, engine room area, stern area, and superstructure area. The ship weight and center of gravity details for different areas include the output of weight and center of gravity information for the cargo hold area, engine room area, bow and stern areas, superstructure, bulwark, and funnel.

[0040] The hull structure includes large openings in the main structure. The equipment reinforcement includes ship equipment bases and reinforcement forms. The large openings in the main structure include large openings in the funnel, large openings in the hoisting opening, and large openings in the engine room. The ship equipment bases and reinforcements include generator bases and deck crane bases. By performing finite element analysis on the hull structure and ship equipment bases and reinforcement forms, the location and size of the large openings in the structure are optimized, and the redundancy of the hull structure and ship equipment bases and reinforcements is obtained. When there is redundancy in the hull structure, the plate thickness at the corresponding location of the hull is reduced.

[0041] The completion of the foundations and reinforcements for major equipment such as generator foundations and deck crane foundations, as well as the determination of major structural openings such as chimney openings, hoisting openings, and large openings in the engine room, are key points for controlling structural weight. New structural forms, such as new foundation designs (which require fewer plates or profiles than older foundations, resulting in lighter weight), are employed. SPD software analysis is used to optimize structural dimensions. New equipment foundations and reinforcement methods are adopted to reduce structural redundancy. New lightweight structural materials are used to further reduce weight.

[0042] The reduction of various allowances in ship sections is achieved by setting the ship section mounting to a zero-allowance docking configuration, thereby reducing the weight of the ship sections. Lightweight design of ship equipment bases and reinforcements specifically involves reducing the use of permanent tooling to fix ship equipment bases. On one hand, the number of components to be welded on the plate frame is strictly counted, the amount of welding on the plate frame is calculated, and welding shrinkage compensation values ​​are set meticulously according to the "Precision Planning Guide," changing the previous method of roughly setting welding shrinkage compensation values ​​and other allowances and then trimming them later. This effectively reduces the weight of the hull structure during the sectioning stage. On the other hand, with the upgrading and optimization of production equipment and the improvement of the technical level of on-site construction personnel, the deformation of sections during construction can be effectively controlled. By continuously absorbing the experience of on-site construction personnel, the mounting allowances and other construction allowances of sections are iteratively optimized, gradually reducing the mounting allowances.

[0043] The extraction of weight information for various parts of the hull at different stages includes weight information for the bow region, cargo hold region, engine room region, stern region, and superstructure region. The weight changes of various parts of the hull during the detailed design stage and the production design stage are compared to ensure that the weight of various parts of the hull changes in an orderly manner at each stage.

[0044] When building a ship, we typically divide the entire vessel into several regions based on its location. Each region contains several sections. The SPD software's built-in weight center of gravity extraction function can extract the detailed weight center of gravity of a single section, or output the weight center of gravity information for all sections of the entire ship. Once we have the weight information for all sections, we can compare the changes in the weight center of gravity of the same region at different stages, and also compare the changes in the weight center of gravity of a single section at different stages.

[0045] The main tasks of the production design phase are to combine the specific technological conditions of the shipyard to draw and convert all the construction drawings required for construction, and to compile specific construction process specifications and other technical documents. While the main structural dimensions have been confirmed in the detailed design phase, some factors still affect the weight of the hull structure, such as various welding shrinkage allowances added due to construction process requirements. These factors affecting the hull structure weight cannot be avoided, nor can they be completely eliminated during the section completion and assembly phases. Furthermore, the production design phase requires reinforcement of many small pieces of equipment, such as pump sets, cooling units, oil separators, air cylinders, and lifting beams. Therefore, weight control measures in the production design phase mainly focus on improving section and assembly accuracy, reducing the required allowance values, implementing lightweight design for the base and reinforcements to reduce structural redundancy, researching new tooling forms to reduce permanent tooling, and establishing rigorous material usage principles to reduce material substitutions.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A monitoring method for lightweight structural design of LNG ships, characterized in that, The method specifically includes the following steps: S1 clarifies the composition of the design phases within the ship design lifecycle, which includes the preliminary design phase, detailed design phase, production design phase, and final design phase, and analyzes the factors affecting the ship's lightship weight in each phase. S2, Preliminary design phase, calculating the empty weight of the ship using empirical formulas; S3, Detailed Design Stage: Based on the empty ship weight calculated in S2 and the ship design software, the full ship model information is integrated to clarify the ship weight center details in different areas. S4. Based on the detailed information on the ship's weight center of gravity in different regions, optimize the hull structure and the equipment base and reinforcement scheme. The hull structure includes large openings in the main structure. The reinforcement scheme includes ship equipment bases and reinforcement methods. The large openings in the main structure include large openings in the funnel, large openings in the hoisting opening, and large openings in the engine room. The ship equipment bases and reinforcements include generator bases and deck crane bases. By performing finite element analysis on the hull structure and ship equipment bases and reinforcement methods, the location and size of the large openings in the structure are optimized, and the redundancy of the hull structure and ship equipment bases and reinforcements is obtained. When there is redundancy in the hull structure, the plate thickness at the corresponding location of the hull is reduced. S5, Production Design Stage: Based on the integrated full-ship model information, reduce the various allowance values ​​for ship sections and carry out lightweight design for ship equipment bases and reinforcements. The reduction of various allowance values ​​for ship sections is achieved by setting the ship section mounting to a zero-allowance docking, reducing the weight of the ship sections, and by carrying out lightweight design of the ship equipment base and reinforcement, specifically by reducing the use of permanent tooling for fixing the ship equipment base. S6, the final design stage, is based on domestically produced ship design software and relies on the ship model information completed at each stage. The weight information of each part of the hull at different stages is extracted and compared with the relevant areas of the hull at different stages to check the weight changes of each part of the ship at different stages. When the weight of each part of the ship at different stages does not meet the design requirements, the hull structure and equipment base are re-optimized and strengthened in the detailed design stage until the design requirements are met.

2. The monitoring method for lightweight design of LNG ship structures according to claim 1, characterized in that, The factors affecting the empty weight of a ship are specifically: equipment selection in the preliminary design stage, plate thickness selection in the detailed design stage, and design reinforcement arrangements in the production design stage.

3. The monitoring method for lightweight structural design of LNG ships according to claim 1, characterized in that, The calculation of the empty ship weight in S2 is as follows: ， Where WH is the weight of hull steel in tons; k is the hull steel weight coefficient; C is the regression coefficient; L is the ship length; B is the ship breadth; and D is the ship depth.

4. The monitoring method for lightweight design of LNG ship structures according to claim 1, characterized in that, The ship design software is SPD. The ship design software integrates the whole ship model information including the bow area, cargo hold area, engine room area, stern area and superstructure area. The ship weight and center of gravity details of different areas include outputting the weight and center of gravity information of the cargo hold area, the engine room area, the bow and stern areas, the superstructure, the bulwark, and the funnel.

5. A monitoring method for lightweight structural design of LNG ships according to claim 1, characterized in that, The extraction of weight information for various parts of the hull at different stages includes weight information for the bow region, cargo hold region, engine room region, stern region, and superstructure region. The weight changes of various parts of the hull during the detailed design stage and the production design stage are compared to ensure that the weight of various parts of the hull changes in an orderly manner at each stage.

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