Steel-aluminum hybrid ship deck structure and design method thereof

Abstract

The application relates to the technical field of large ships and ocean engineering, and discloses a steel-aluminum mixed ship deck structure and a design method thereof. The deck structure comprises an aluminum alloy deck, aluminum alloy longitudinal spars of a groove-shaped section arranged uniformly and parallel to each other along the ship length direction under the aluminum alloy deck, and a steel frame connected with the aluminum alloy longitudinal spars through steel-aluminum transition joints. The steel frame comprises strong transverse beams and weak transverse beams arranged along the ship width direction and longitudinal girders arranged along the ship length direction. The section of the components of the steel frame is all I-shaped section. The strong transverse beams and the weak transverse beams are arranged in parallel and at intervals, and the longitudinal girders are arranged in parallel and perpendicularly intersect the strong transverse beams and the weak transverse beams. The application adopts a design concept without a belt plate, the thickness of the deck plate does not need to meet the minimum thickness size requirement in the specification, the width of the deck belt plate is not taken into account when the moment of inertia and the section modulus of the components are calculated, the lightweight design of the deck is realized, the center of gravity is reduced, the stability of the ship is improved, the fuel consumption is reduced, and the navigation cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of large ship and marine engineering technology, specifically to a steel-aluminum hybrid ship deck structure and its design method. Background Technology

[0002] Current ship hull structural designs primarily utilize marine steel, and hull structures are based on the strip plate theory. Classification society regulations calculate the section modulus and moment of inertia of components along with the strip plate, and deck plate thickness must meet the minimum thickness requirements specified in the regulations. However, steel plates constitute a significant proportion of a ship's weight, and based on the strip plate theory, there is very limited design space for lightweighting this portion of deck plate. While classification society regulations allow the use of aluminum alloys to replace marine steel to achieve lightweighting, the yield strength of welded aluminum alloys is significantly reduced (e.g., the yield strength of 5083 series is only 125 MPa). Furthermore, aluminum alloys have a lower elastic modulus E, only about one-third that of steel. Since structural deformation is inversely proportional to the elastic modulus E, large-span aluminum alloy structures suffer from insufficient strength redundancy and stiffness. This has limited the application of aluminum alloys in the structural design of smaller ships, preventing their widespread use in large-scale ship designs. Therefore, a new technical solution is needed to address these issues. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a lighter deck structure form and its design method while ensuring structural strength and stiffness.

[0004] To solve the above technical problems, the present invention provides a steel-aluminum hybrid ship deck structure, which includes an aluminum alloy deck. Under the aluminum alloy deck, parallel aluminum alloy longitudinals are evenly arranged along the ship's length. The aluminum alloy longitudinals are connected to the underlying steel strong beams, weak beams and longitudinal girder through steel-aluminum transition joints. The strong beams and weak beams are spaced apart and parallel to each other along the ship's width. The longitudinal girder is arranged parallel along the ship's length and intersects the strong beams and weak beams perpendicularly.

[0005] By adopting the above technical solutions, steel-aluminum hybrid ship deck structures can effectively reduce structural weight and achieve larger spans, enabling aluminum alloys to be used in the deck structure design of large ships.

[0006] Preferably, the aluminum alloy longitudinal rib has a channel-shaped cross section, and its top panel is welded to the aluminum alloy deck.

[0007] By adopting the above technical solution, without considering the deck plate, using aluminum alloy longitudinal ribs with a channel cross section can provide a larger section modulus and provide sufficient strength for the ship deck structure.

[0008] Preferably, the strong crossbeams, weak crossbeams, and longitudinal girder are made of AH36 high-strength steel, and all have I-shaped cross sections, with their tops on the same horizontal plane.

[0009] By adopting the above technical solutions and using high-strength steel, the size of the components under the same stress level is smaller than that of ordinary steel, and the I-shaped cross-section further provides a larger section modulus, thus meeting the strength requirements of the specifications.

[0010] Preferably, the steel-aluminum transition joint adopts an aluminum-titanium-steel composite transition joint.

[0011] By adopting the above technical solution, the aluminum-titanium-steel composite transition joint has high tensile strength and large strength redundancy.

[0012] A design method for a steel-aluminum hybrid ship deck structure includes the following steps: S1) In accordance with the requirements of ship specifications, first design a conventional longitudinal frame deck structure, including the form, size and spacing of the deck components when the material is high-strength steel, including the deck thickness, the cross-sectional dimensions of the bulb flat steel longitudinal ribs, the longitudinal rib spacing, the dimensions of the T-section beams, the beam spacing, the dimensions of the T-section longitudinal girder, and the longitudinal girder spacing.

[0013] S2) Initiate the lightweight design without deck plates, determining the materials, forms, dimensions, and spacing of the deck plates, longitudinal stiffeners, strong crossbeams, weak crossbeams, and longitudinal girder in the deck structure. The strong crossbeams, weak crossbeams, and longitudinal girder are made of AH36 high-strength steel with I-beam sections; the longitudinal stiffeners are made of aluminum alloy with channel sections; and the deck plates are made of aluminum alloy. The spacing of the components remains consistent with the conventional deck structure spacing in S1). Strong and weak crossbeams and longitudinal girder must ensure that their section modulus is not lower than that of the high-strength steel crossbeams and longitudinal girder designed in S1); the section modulus of aluminum alloy longitudinal girders shall not be lower than the value calculated according to the following formula: cm 3 ,in The section modulus of the high-strength steel longitudinal skeleton designed in S1, in cm. 3 ; The material coefficient of aluminum alloy; The initial thickness of the aluminum alloy deck is set at 4mm.

[0014] S3) Perform finite element analysis on the steel strong and weak crossbeams, longitudinal girder, and aluminum alloy longitudinal stiffeners designed in S2). Calculate the maximum equivalent stress and deformation of the strong and weak crossbeams, longitudinal girder, and aluminum alloy longitudinal stiffeners under the self-weight, inertial load, and deck load required by the specification. Verify whether the structure meets the strength and stiffness design requirements specified in the specification without the participation of the aluminum alloy deck. If it does not meet the strength and stiffness design requirements specified in the specification, increase the component dimensions according to the section modulus requirements in S2), reselect the dimensions of the steel strong and weak crossbeams, longitudinal girder, and aluminum alloy longitudinal stiffener components, and repeat S3) until the strength and stiffness design requirements specified in the specification are met.

[0015] S4) Determine the connection methods for the strong crossbeams, weak crossbeams, longitudinal girder and aluminum alloy longitudinal stiffeners, as well as the connection methods for the aluminum alloy longitudinal stiffeners and aluminum alloy deck. Structural transition joints are used to achieve direct welding between the aluminum alloy and steel. The connection method is a suspended connection, meaning that the steel crossbeams and longitudinal girder are connected to the aluminum alloy longitudinal stiffeners via steel-aluminum transition joints, without contacting the aluminum alloy deck. The upper panel of the channel-shaped aluminum alloy longitudinal stiffener is welded to the bottom surface of the aluminum alloy deck. Using a suspended connection significantly reduces the contact area between the steel and aluminum alloy, reduces the use of structural transition joints, saves costs, and contributes to structural lightweighting.

[0016] S5) Select a suitable steel-aluminum transition joint, or select an aluminum-titanium-steel composite transition joint.

[0017] S6) Verify the performance of the aluminum alloy deck. If the strength and stiffness of the aluminum alloy deck do not meet the specifications, increase the thickness of the aluminum alloy deck and repeat step S6) for verification until the strength and stiffness of the aluminum alloy deck meet the specifications.

[0018] By adopting the above technical solution, this design method is based on the concept of stripless design and supplemented by the section modulus formula required by ship specifications. When calculating the moment of inertia and section modulus of the components, the width of the aluminum alloy deck strip is not taken into account, and the deck thickness does not need to meet the minimum thickness requirement in the specifications. The designed deck structure has a significant weight reduction effect, which helps to lower the center of gravity, improve ship stability, and help reduce fuel consumption and reduce navigation costs.

[0019] Preferably, in step S2), the component dimensions are determined based on the design concept of no-strip plate: the aluminum alloy deck does not participate in strength and is only considered as the frame skin. The thickness of the aluminum alloy deck does not need to meet the minimum thickness requirement in the specification. The width of the deck strip is not included when calculating the moment of inertia and section modulus of the component.

[0020] By adopting the above technical solutions, the thickness of aluminum alloy decks is no longer constrained by the minimum plate thickness specified in the regulations, which increases the space for lightweight design of ship deck plates.

[0021] Preferably, in step S6), a finite element analysis is performed on the steel-aluminum hybrid ship deck structure to calculate the maximum equivalent stress and deformation of the aluminum alloy deck under the self-weight, inertial load, and deck load required by the specification, and to check its strength and stiffness to see if they meet the specification requirements.

[0022] By adopting the above technical solutions and using finite element simulation, the stress conditions of the structure can be simulated and predicted during the design process, proving that the steel-aluminum hybrid structure has the strength and stiffness required for ship applications, thus improving the safety of the design scheme.

[0023] Compared with the prior art, the present invention has the following advantages: 1. The steel-aluminum hybrid ship deck structure of the present invention can effectively reduce the structural weight and achieve a larger span, enabling aluminum alloys to be used in the deck structure design of large ships.

[0024] 2. The design method of this invention is based on the design concept of a stripless deck, supplemented by the section modulus formula required by ship specifications. When calculating the moment of inertia and section modulus of the components, the width of the aluminum alloy deck strip is not taken into account, and the deck thickness does not need to meet the minimum thickness requirement in the specifications. The designed deck structure has a significant weight reduction effect, which helps to lower the center of gravity, improve ship stability, and help reduce fuel consumption and reduce navigation costs.

[0025] 3. The aluminum alloy deck of this invention does not participate in strength and is only considered as the frame skin. Its deck thickness is not constrained by the minimum plate thickness in the specification. When calculating the moment of inertia and section modulus of the components, the width of the aluminum alloy deck strip is not included, thereby increasing the space for lightweight design of the deck material. Attached Figure Description

[0026] Figure 1 is a structural diagram of the steel-aluminum hybrid ship deck of the present invention.

[0027] Figure 2 This is a cross-sectional schematic diagram of the steel-aluminum hybrid ship deck structure of the present invention.

[0028] Figure 3 This is a longitudinal cross-sectional schematic diagram of the steel-aluminum hybrid ship deck structure of the present invention.

[0029] Figure 4 yes Figure 1 Enlarged schematic diagram of the Sinosteel-aluminum transition joint 3.

[0030] The components include: 1. Aluminum alloy deck; 2. Aluminum alloy longitudinal beams; 3. Steel-aluminum transition joints; 4. Strong crossbeams; 5. Weak crossbeams; and 6. Longitudinal girder. Detailed Implementation

[0031] As shown in Figures 1-3, a steel-aluminum hybrid ship deck structure includes an aluminum alloy deck 1. Parallel aluminum alloy longitudinals 2 are evenly arranged along the ship's length below the aluminum alloy deck 1. The aluminum alloy longitudinals 2 are connected to the underlying strong transverse beams 4, weak transverse beams 5, and longitudinal girder 6 via steel-aluminum transition joints 3. The strong transverse beams 4 and weak transverse beams 5 are spaced apart and parallel to each other along the ship's width. The longitudinal girder 6 is arranged parallel to the ship's length and intersects the strong transverse beams 4 and weak transverse beams 5 perpendicularly. This steel-aluminum hybrid structure, while ensuring strength and stiffness, effectively reduces structural weight, achieving a lightweight deck design, and allows for larger spans, enabling the application of aluminum alloys in the deck structure design of large ships.

[0032] The aluminum alloy longitudinal stiffener 2 has a channel-shaped cross-section, and its top panel is welded to the aluminum alloy deck 1. Ignoring the deck plate, the channel-shaped cross-section of the component provides a larger section modulus, ensuring sufficient strength for the ship's deck structure.

[0033] The strong crossbeam 4, weak crossbeam 5, and longitudinal girder 6 are all made of AH36 high-strength steel, with I-beam cross sections and their tops on the same horizontal plane. Using high-strength steel results in smaller dimensions for horizontal members under the same stress compared to ordinary steel, and the I-beam cross section further provides a larger section modulus to meet the strength requirements specified in the code.

[0034] like Figure 4 As shown, the steel-aluminum transition joint 3 is an aluminum-titanium-steel composite transition joint. Its upper end is welded to the aluminum alloy longitudinal stiffener 2, and its lower end is welded to the strong crossbeam 4, the weak crossbeam 5, and the longitudinal girder 6. The aluminum-titanium-steel composite transition joint has high tensile strength and a large strength redundancy.

[0035] A design method for a steel-aluminum hybrid ship deck structure includes the following steps: S1) In accordance with the requirements of ship specifications, first design a conventional longitudinal frame deck structure, including the form, size and spacing of the deck components when the material is high-strength steel, including the deck thickness, the cross-sectional dimensions of the bulb flat steel longitudinal ribs, the longitudinal rib spacing, the dimensions of the T-section beams, the beam spacing, the dimensions of the T-section longitudinal girder, and the longitudinal girder spacing.

[0036] S2) Initiating the lightweight design without slabs, the materials, forms, dimensions, and spacing of the deck plates, longitudinal stiffeners, strong transverse beams 4, weak transverse beams 5, and longitudinal girder 6 in this application's deck structure were determined. Strong transverse beams 4, weak transverse beams 5, and longitudinal girder 6 are made of AH36 high-strength steel with I-beam cross-sections. The longitudinal stiffeners are made of aluminum alloy with channel cross-sections. The deck plates are made of aluminum alloy. The spacing of the components is consistent with the spacing of the conventional deck structure in S1).

[0037] The section modulus of the steel strong and weak crossbeams and longitudinal girder 6 must be no less than that of the high-strength steel crossbeams and longitudinal girder designed in S1); the section modulus of the aluminum alloy longitudinal girder 2 must be no less than the value calculated according to the following formula: cm 3 ,in The section modulus of the high-strength steel longitudinal skeleton designed in S1), in cm 3 ; The material coefficient of aluminum alloy; The component dimensions are determined based on the stripless design concept: Stripless design assumes that the aluminum alloy deck 1 does not contribute to strength but is only considered as the frame skin. Therefore, the thickness of the aluminum alloy deck 1 does not need to meet the minimum thickness requirement in the specifications, and the deck strip width is not included when calculating the moment of inertia and section modulus of the component. However, according to ship specifications, the cross sections of beam 4, weak beam 5, and longitudinal girder 6 are all T-shaped. The specifications require that a portion of the width of the aluminum alloy deck 1 be included in the cross section calculation; this portion of the aluminum alloy deck 1 width is called the deck strip. The thickness of the aluminum alloy deck 1 is not constrained by the minimum thickness requirement in the specifications, increasing the design flexibility for lightweight ship deck plates. The initial thickness of the aluminum alloy deck 1 is taken as 4mm.

[0038] S3) Perform finite element analysis on the steel strong and weak crossbeams, longitudinal girder 6, and aluminum alloy longitudinal stiffener 2 designed in S2). Calculate the maximum equivalent stress and deformation of the strong crossbeam 4, weak crossbeam 5, longitudinal girder 6, and aluminum alloy longitudinal stiffener 2 under the self-weight, inertial load, and deck load required by the specification. Verify whether the structure meets the strength and stiffness design requirements specified in the specification without the participation of aluminum alloy deck 1. If it does not meet the strength and stiffness design requirements specified in the specification, increase the component dimensions appropriately according to the section modulus requirements in S2), reselect the dimensions of the steel strong crossbeam 4, weak crossbeam 5, longitudinal girder 6, and aluminum alloy longitudinal stiffener 2, and repeat S3) until the strength and stiffness design requirements specified in the specification are met.

[0039] S4) Determine the connection methods between the strong crossbeam 4, weak crossbeam 5, longitudinal girder 6 and aluminum alloy longitudinal stiffener 2, as well as between the aluminum alloy longitudinal stiffener 2 and aluminum alloy deck 1. Due to the differences in physical properties and metallurgical incompatibility between aluminum alloy and steel, it is difficult to achieve an effective connection between the two by direct welding. Therefore, structural transition joints are needed to achieve direct welding between aluminum alloy and steel. The connection method is a suspended connection, that is, the steel crossbeams and longitudinal stiffeners 6 are connected to the aluminum alloy longitudinal stiffener 2 through steel-aluminum transition joints 3, without contacting the aluminum alloy deck 1. The upper panel of the channel-shaped aluminum alloy longitudinal stiffener 2 is welded to the bottom surface of the aluminum alloy deck 1. The suspended connection will greatly reduce the contact area between the steel and the aluminum alloy deck 1, reduce the use of structural transition joints, save costs, and contribute to structural lightweighting.

[0040] S5) Select a suitable steel-aluminum structural transition joint, taking into account the tensile strength and weight of the joint. Due to the high tensile strength of the aluminum-titanium-steel composite transition joint, it is recommended.

[0041] S6) Verify the performance of aluminum alloy deck 1. Although the stripless design concept does not consider the participation of deck strips in the design, the aluminum alloy deck 1 does participate in the stress when the actual structure is under load. Finite element analysis is performed on the steel-aluminum hybrid ship deck structure to calculate the maximum equivalent stress and deformation of aluminum alloy deck 1 under the self-weight, inertial load, and deck load required by the specifications, and to verify its strength and stiffness to ensure they meet the specifications. Finite element simulation is used to simulate and predict the stress situation of the structure during the design phase, proving that the steel-aluminum hybrid structure has the strength and stiffness required for ship applications, thus improving the safety of the design scheme. If the strength and stiffness of aluminum alloy deck 1 do not meet the specifications, the thickness of aluminum alloy deck 1 is increased, and step S6) is repeated for verification until the strength and stiffness of aluminum alloy deck 1 meet the specifications.

[0042] This application's design method is based on the concept of a stripless design, supplemented by the section modulus formula required by ship specifications. When calculating the moment of inertia and section modulus of the components, the width of the aluminum alloy deck 1 strip is not taken into account, and the thickness of the aluminum alloy deck 1 strip does not need to meet the minimum thickness requirements in the specifications. The designed deck structure has a significant weight reduction effect, which helps to lower the center of gravity, improve ship stability, and help reduce fuel consumption and navigation costs. Steel-aluminum hybrid ship deck structures can achieve larger spans, allowing aluminum alloys to be used in the deck structure design of large ships.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A design method for a steel-aluminum hybrid ship deck structure, characterized in that, The structure includes a steel-aluminum hybrid ship deck, which includes an aluminum alloy deck. Underneath the aluminum alloy deck, parallel aluminum alloy longitudinals are evenly arranged. The aluminum alloy longitudinals are connected to the underlying steel strong beams, weak beams and longitudinal girder via steel-aluminum transition joints. The strong beams and weak beams are spaced apart and parallel to each other along the ship's width. The longitudinal girder is arranged parallel to the ship's length and intersects the strong beams and weak beams perpendicularly. The design method includes the following steps: S1) In accordance with the requirements of ship specifications, first design a conventional longitudinal frame deck structure according to the specifications, including the form, size and spacing of the deck components when the material is high-strength steel, including the deck thickness, the cross-sectional dimensions of the bulb flat steel longitudinal ribs, the longitudinal rib spacing, the dimensions of the T-section beams, the beam spacing, the dimensions of the T-section longitudinal girder, and the longitudinal girder spacing. S2) Begin the lightweight design without deck plates, determining the materials, forms, dimensions, and spacing of the deck plates, longitudinal girders, strong beams, weak beams, and longitudinal girder in the deck structure; the strong beams, weak beams, and longitudinal girder are made of AH36 high-strength steel with I-beam sections, the longitudinal girders are made of aluminum alloy with channel sections, and the deck plates are made of aluminum alloy; the spacing of the components is consistent with the spacing of the conventional deck structure in S1); Strong and weak crossbeams and longitudinal girder must ensure that their section modulus is not lower than that of the high-strength steel crossbeams and longitudinal girder designed in S1); the section modulus of aluminum alloy longitudinal girders shall not be lower than the value calculated according to the following formula: cm 3 ,in The section modulus of the high-strength steel longitudinal skeleton designed in S1), in cm 3 ; The material coefficient of aluminum alloy; The initial thickness of the aluminum alloy deck is 4mm; S3) Perform finite element analysis on the steel strong and weak crossbeams, longitudinal girder, and aluminum alloy longitudinal stiffeners designed in S2). Calculate the maximum equivalent stress and deformation of the strong and weak crossbeams, longitudinal girder, and aluminum alloy longitudinal stiffeners under the self-weight, inertial load, and deck load required by the specification. Verify whether the structure meets the strength and stiffness design requirements specified in the specification without the participation of the aluminum alloy deck. If it does not meet the strength and stiffness design requirements specified in the specification, increase the component size according to the section modulus requirements in S2), reselect the size of the steel strong and weak crossbeams, longitudinal girder, and aluminum alloy longitudinal stiffener components, and repeat S3) until the strength and stiffness design requirements specified in the specification are met. S4) Determine the connection methods of strong crossbeams, weak crossbeams, longitudinal girder and aluminum alloy longitudinal stiffener, as well as the connection methods of aluminum alloy longitudinal stiffener and aluminum alloy deck; use structural transition joints to achieve direct welding of aluminum alloy and steel; the connection method is a suspended connection, that is, the steel crossbeams and longitudinal girder are connected to the aluminum alloy longitudinal stiffener through steel-aluminum transition joints and do not contact the aluminum alloy deck; the upper panel of the channel-shaped aluminum alloy longitudinal stiffener is welded to the bottom surface of the aluminum alloy deck. S5) Select a suitable steel-aluminum transition joint: aluminum-titanium-steel composite transition joint; S6) Verify the performance of the aluminum alloy deck; if the strength and stiffness of the aluminum alloy deck do not meet the specifications, increase the thickness of the aluminum alloy deck and repeat step S6) to verify until the strength and stiffness of the aluminum alloy deck meet the specifications.

2. The design method for a steel-aluminum hybrid ship deck structure according to claim 1, characterized in that: The aluminum alloy longitudinal rib has a channel-shaped cross section, and its top panel is welded to the aluminum alloy deck.

3. The design method for a steel-aluminum hybrid ship deck structure according to claim 1, characterized in that: The strong crossbeams, weak crossbeams, and longitudinal girder are all made of AH36 high-strength steel, and their cross-sections are all I-shaped, with their tops on the same horizontal plane.

4. The design method for a steel-aluminum hybrid ship deck structure according to claim 1, characterized in that: The steel-aluminum transition joint is an aluminum-titanium-steel composite transition joint.

5. The design method for a steel-aluminum hybrid ship deck structure according to claim 1, characterized in that: In step S2), the component dimensions are determined based on the design concept of no-strip plate: the aluminum alloy deck does not participate in strength and is only considered as the frame skin. The thickness of the aluminum alloy deck does not need to meet the minimum thickness requirement in the specification. The width of the deck strip is not included when calculating the moment of inertia and section modulus of the component.

6. The design method for a steel-aluminum hybrid ship deck structure according to claim 1, characterized in that: In step S6), a finite element analysis is performed on the steel-aluminum hybrid ship deck structure to calculate the maximum equivalent stress and deformation of the aluminum alloy deck under the self-weight, inertial load, and deck load required by the specifications, and to check its strength and stiffness to see if they meet the specifications.

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