CN114919710B - Grid type box body floating raft structure and design method thereof - Google Patents
Grid type box body floating raft structure and design method thereof Download PDFInfo
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- 229910000746 Structural steel Inorganic materials 0.000 description 5
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- 239000002356 single layer Substances 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
- B63B35/58—Rafts, i.e. free floating waterborne vessels, of shallow draft, with little or no freeboard, and having a platform or floor for supporting a user
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B71/00—Designing vessels; Predicting their performance
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B73/00—Building or assembling vessels or marine structures, e.g. hulls or offshore platforms
- B63B73/20—Building or assembling prefabricated vessel modules or parts other than hull blocks, e.g. engine rooms, rudders, propellers, superstructures, berths, holds or tanks
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/70—Wind energy
- Y02E10/727—Offshore wind turbines
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
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Abstract
The invention relates to a net frame type box body floating raft structure and a design method, wherein the structure comprises a net frame structure, an upper panel, a lower panel and a bulkhead; the grid structure is a space three-dimensional frame structure consisting of a transverse plane truss structure, a longitudinal plane truss structure and a horizontal plane truss structure; the plane truss structure is a hollow lattice type flexural member formed by connecting rod pieces, and the rod pieces comprise chord members and web members; the upper panel is arranged on the upper surface of the horizontal plane truss at the top, and the lower panel is arranged on the upper surface of the horizontal plane truss at the bottom; the bulkhead is arranged inside the grid structure and is connected with the upper panel and/or the lower panel; the method comprises the steps of grid structure design, plate design and integral check of the buoyant raft. According to the invention, the grid structure is applied to the traditional floating raft structure design to form the grid type box floating raft structure, so that the integration design of the raft structure and the cabin structure and the lightweight design of the cabin raft vibration isolation system can be realized, and the grid type box floating raft structure has better vibration and noise reduction effects compared with the traditional plate type floating raft structure under the same weight.
Description
Technical Field
The invention belongs to the technical field of ship vibration isolation structures, and particularly relates to a grid type box body floating raft structure and a design method thereof.
Background
In the sailing process of a ship, a power system consisting of a plurality of power devices inevitably brings vibration and noise effects to a main body. Although complete elimination of structural vibrations and noise is not possible under existing conditions, it is necessary to limit the vibrations of the vessel to an acceptable range in order for the entire system to operate safely and stably.
In the past thirty years, a great deal of theoretical and experimental researches are carried out on the aspects of vibration reduction and noise reduction of underwater vehicles at home and abroad, the design of a vibration isolation system of mechanical equipment is developed from an early single-layer unidirectional simple vibration isolation device to a current multi-layer multidirectional space three-dimensional floating raft vibration isolation device, and the vibration isolation performance is greatly improved. The floating raft vibration isolation is a novel and complex vibration isolation method, and is used in projects with high requirements on installation environment and vibration isolation effect, wherein vibration isolation is carried out on a plurality of power devices at the same time. The main principle of the vibration isolation of the floating raft is that a plurality of mechanical devices are arranged on the same raft frame through vibration isolators, and the raft frame and the base are also connected through the vibration isolators, so that the devices, the raft frame and the base form a multi-degree-of-freedom multi-layer vibration isolation system. The floating raft vibration isolation system is mainly applied to ship vibration isolation engineering, and the vibration isolation performance of the floating raft vibration isolation system is superior to that of a single-layer vibration isolation system and a double-layer vibration isolation system.
The traditional buoyant raft structure is used as the middle quality of the buoyant raft vibration isolation device, generally adopts a planar plate frame type structural design, can only realize the functions of an equipment installation platform and damping vibration, and has single function and structural style. On the other hand, the realization of vibration damping effect of the traditional floating raft vibration isolation device mainly depends on the 'mass effect', the vibration damping effect is in direct proportion to the weight of the middle raft frame structure, and more weight and space resources are needed to be consumed for achieving better vibration damping effect. Therefore, a new method for designing a raft structure is required, and the raft structure is light in weight and has an excellent vibration reduction effect.
Disclosure of Invention
The invention aims to solve the technical problems of the prior art and provides a grid type box body floating raft structure and a design method thereof, wherein the grid type box body floating raft structure in a three-dimensional space is formed by applying a grid structure to the traditional floating raft structure design.
The technical scheme adopted by the invention for solving the technical problems is as follows:
a grid type box body floating raft structure comprises a grid structure, an upper panel, a lower panel and a bulkhead; the grid structure is a space three-dimensional frame structure formed by a transverse, longitudinal and horizontal plane truss structure; the plane truss structure is a hollow lattice type flexural member formed by connecting rod pieces, and the rod pieces comprise chord members and web members; the upper panel is arranged on the upper surface of the horizontal plane truss at the top, and the lower panel is arranged on the upper surface of the horizontal plane truss at the bottom; the bulkhead is arranged inside the grid structure and is connected with the upper panel and/or the lower panel.
In the scheme, the bulkhead adopts a plane bulkhead formed by the stiffening material and the bulkhead plate.
In the scheme, the grid structure, the upper panel, the lower panel and the bulkhead are connected in a welding mode.
In the scheme, the net frame type box body floating raft structure also serves as a ship cabin.
Correspondingly, the invention also provides a design method of the net frame type box body buoyant raft structure, which comprises the following steps:
S1, designing a grid structure, comprising
S1.1, selecting a proper material based on the action of each rod piece on the grid structure;
s1.2, designing a grid structure type based on a vibration isolation design target;
S1.3, designing parameters including rod length, section form and slenderness ratio of the rod piece according to the determined grid structure type;
s1.4, designing nodes based on the determined rod pieces;
S1.5, carrying out load design of the planar truss structure according to the actual use environment of the grid structure, wherein the load comprises a permanent load and a variable load; for the plane truss structure, according to the designed load, carrying out cross-section strength, stability, rigidity and node check of the plane truss structure based on internal force analysis;
s2, designing a plate, comprising
S2.1, selecting proper materials according to the application of the plate and the load born by the plate, wherein the plate comprises an upper panel, a lower panel and a bulkhead;
s2.2, designing the panel, wherein the maximum bending stress and deflection value of the designed panel are smaller than the allowable value in consideration of the weight of equipment on the panel;
S2.3, designing the bulkhead, including designing the thickness of the bulkhead plate and the size of the stiffening material, and arranging and number of the bulkheads;
S3, integral check of the buoyant raft, which comprises
Static checking is carried out on the whole floating raft, including checking in forward floating and inclined states, and the maximum stress of the structure in the two states is smaller than the yield stress of the material;
vibration isolation checking is carried out on the whole floating raft, and the vibration isolation capability of the designed net rack floating raft in the full frequency band is larger than that of the traditional plate rack floating raft under the same weight.
In the method, the selection range of the rod piece material and the plate material is as follows: 16Mn steel, Q235, Q345, Q390, Q420, Q460 steel.
In the above method, in step S1.2, the design of the grid structure pattern includes determining a planar truss structure pattern, a grid height, and a grid size; the planar truss structure types include prasux trusses, waln trusses, feng trusses, and arch trusses.
In the above method, in step S1.4, the node type includes lap K shape, T shape, and plane KT shape; the joint of the welded branch pipe and the main pipe avoids eccentricity as much as possible, and if the eccentricity cannot be avoided, the value of the joint is not suitable to exceed the limit of the following formula:
-0.55.ltoreq.e/D (or e/h). Ltoreq.0.25
Wherein e is the eccentricity;
D, the outer diameter of the circular tube main pipe;
h, the section height of the rectangular pipe main pipe in the connecting plane;
When a plurality of branch pipes are lapped at the joints of the steel pipe net frame, the lapped pipes are selected in a certain sequence, and in the K-shaped or N-shaped joint with gaps, the gaps of the branch pipes are not smaller than the sum of the wall thicknesses of the two branch pipes; in the overlapping K-shaped or N-shaped joint, the overlapping rate should satisfy 25% or more and less than or equal to O v% or less and 100% or less, and the connection weld between the branch pipes of the overlapping portion should be ensured to reliably transmit the internal force.
In the method, in the step S2.3, the thickness of the bulkhead plate and the section modulus of the stiffening material meet the standard requirements; the arrangement and the number of the bulkheads are divided by the internal space of the floating raft, and the longitudinal bulkheads, the transverse bulkheads or the half bulkheads are selected at proper positions to realize uniform arrangement, so that the number of the bulkheads is reduced as much as possible under the condition of meeting the requirement of strength design.
In the above method, in step S3, the integral checking of the buoyant raft further includes performing impact resistance checking on the buoyant raft structure, and the stress response of the structure under the effect of environmental impact should meet the structural strength requirement.
The invention has the beneficial effects that:
1. the net frame type box body floating raft structure has the following advantages:
1) The raft structure and the cabin structure can be fused, the reinforcement design of cabin bulkhead reinforcement materials can be utilized, the overall rigidity and the strength level of the middle part of the raft frame can be effectively improved, and the light weight design effect of the cabin raft vibration isolation system can be achieved on the basis that the rod member structure is utilized on the periphery to meet the requirements of rigidity and strength;
2) The raft frame structure is not only an installation platform of equipment, but also has a cabin function, can improve the loading capacity of the whole cabin floating raft, is convenient for integrally and intensively arranging all auxiliary machine systems on the floating raft, and solves the problem of vibration reduction and isolation of a pipeline system by isolating equipment, pipelines and related auxiliary devices through the floating raft; the system on the floating raft can realize fluid exchange in the floating raft as much as possible, so that pipelines for connecting the floating raft with the outside can be reduced, and vibration transmission channels between the cabin raft and the boat body can be effectively reduced;
3) The box body floating raft structure can realize the integrated installation of more equipment, and vibration isolation system mass effect is big, and mass effect is more obvious, helps promoting low frequency vibration isolation effect.
2. The design method of the net frame type box body floating raft structure has the following advantages:
1) The grid type box body floating raft based on the flow design can realize the fusion design of a raft frame structure and a cabin structure and the lightweight design of a cabin raft vibration isolation system, and has better vibration reduction and noise reduction effects compared with the traditional plate frame type floating raft structure under the same weight;
2) Can guide the design of the floating raft structure similar to the net rack box body.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
FIG. 1 is a schematic structural view of a floating raft structure of a net frame type box body of the invention;
FIG. 2 is a flow chart of the design method of the net rack type box body buoyant raft structure of the invention;
FIG. 3 is a schematic representation of the type of planar truss structure;
FIG. 4 is a schematic view of a longitudinal planar truss structure in an embodiment of the invention;
FIG. 5 is a schematic illustration of a transverse planar truss structure in an embodiment of the invention;
FIG. 6 is a schematic diagram of nodes of a floating raft structure of a cage type box body according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of the main arrangement of the upper layer device in the embodiment of the invention;
fig. 8 is a diagram showing a comparison of vibration isolation effect between a grid-type box body raft structure and a conventional grid-type raft in an embodiment of the present invention.
In the figure: 11. a longitudinal planar truss structure; 12. a transverse planar truss structure; 13. a horizontal planar truss structure; 14. a chord; 15. a web member; 21. an upper panel; 22. a lower panel; 23. a bulkhead.
Detailed Description
For a clearer understanding of technical features, objects and effects of the present invention, a detailed description of embodiments of the present invention will be made with reference to the accompanying drawings.
The invention provides a net rack type box body floating raft structure which is mainly used for being elastically installed in a cabin section of a ship, and achieves the purposes of impact resistance protection and equipment vibration isolation for important equipment and personnel while realizing the functions of an equipment installation platform and the cabin. As shown in fig. 1, the lattice frame type box body buoyant raft structure comprises a lattice frame structure, an upper panel 21, a lower panel 22 and a bulkhead 23. The grid structure is a space three-dimensional frame structure consisting of a transverse, longitudinal and horizontal plane truss structure; the plane truss structure is a hollow lattice type flexural member formed by connecting rods, and the rods comprise chords 14 and web members 15. The upper panel 21, the lower panel 22 and the bulkhead 23 are plate structures, wherein the upper panel 21 is mounted on the upper surface of the top horizontal planar truss structure 13, and the lower panel 22 is mounted on the upper surface of the bottom horizontal planar truss structure 13. The bulkhead 23 is a planar bulkhead composed of stiffening members and bulkhead plates, the bulkhead 23 being mounted inside the grid structure, the bulkhead plates being connected to the upper panel 21 and/or the lower panel 22. The grid structure, the upper panel 21, the lower panel 22 and the bulkhead 23 are connected by adopting a welding mode.
The design flow of the above-mentioned net frame type box body floating raft structure is shown in fig. 2, and comprises the following steps:
s1, grid structure design
S1.1, rod material determination
Based on the function of each rod (chord member and web member) on the grid structure, a proper material is selected. The steel of the grid rod structure is preferably 16Mn steel, Q235, Q345, Q390, Q420 and Q460 steel, and can be selected according to actual needs, and the quality of the steel meets the regulations of the current national standards of carbon structural steel GB/T700 and low alloy high strength structural steel GB/T1591 respectively. In this embodiment, the rod member is made of Q345 steel with a material density of 7.85×10 3kg/m3 and an elastic modulus e=2.06×10 11N/m2, and poisson's ratio σ=0.3.
S1.2 grid Structure type design
The grid structure type is designed based on vibration isolation design targets, including determining a planar truss structure type, a grid height and a grid size.
The planar truss structure is classified into a Pratt truss, a Warren (Warren) truss, a Fink (Fink) truss, and an arch truss according to the stress characteristics and the arrangement of the bars, see fig. 3. The box body buoyant raft structure is influenced by the arrangement of the ship cabins, the height of the box body buoyant raft structure is basically determined, and the box body buoyant raft structure comprises an upper panel and a lower panel which are parallel to each other, and the whole buoyant raft is of a box structure, so that the box body buoyant raft is preferably designed in a parallel chord grid structure, namely a rectangular grid structure, and a regularized Hualunar truss and a praat truss type can be selected for reference design. In combination with the cabin bulkhead 23 arrangement position and the grid structure pattern, a corresponding grid size is obtained.
S1.3, rod parameter determination
According to the determined grid structure type, the rod members (chord members and web members) are designed, and proper rod length, section form, slenderness ratio and the like are selected. The steel pipe structure can comprehensively consider to adopt a round pipe or rectangular pipe structure according to the specific conditions of the components such as stress condition, manufacturing and installation conditions, appearance requirements, economy and the like, and can also be used by mixing the two steel pipes. When the air conditioner is used in a mixing mode, the chord members are rectangular pipes, and the web members are round pipes. The chord member can also adopt H-shaped steel, and the web member adopts rectangular pipes or round pipes. The calculated length and permissible slenderness ratio of the rod should meet the requirements of the relevant regulations. The node design of the structure is reasonable in stress and accords with practical economic benefits.
In this embodiment, the rod members all select rectangular pipe net frame cross sections, and specific dimensions are determined according to actual requirements. The calculated length of the rod piece of the net rack is set smaller than the geometric length of the net rack, the web members are designed in the form of single-layer web members (namely, only one layer of net rack), and the factors of the allowable slenderness ratio of the rod piece are considered as well as the chord members.
S1.4 node design
Based on the determined rod piece, node design is carried out, and the types of the contained nodes are lap joint K-shaped, T-shaped, plane KT-shaped and the like.
For the node design of this embodiment, it should be noted that the directly welded steel pipe node requires that the connection of the branch pipe and the main pipe be as free of eccentricity as possible. If eccentricity cannot be avoided, the value should not exceed the limit of the following formula:
-0.55.ltoreq.e/D (or e/h). Ltoreq.0.25
Wherein e is the eccentricity;
D, the outer diameter of the circular tube main pipe;
h, the section height of the rectangular pipe main pipe in the connecting plane.
When a plurality of branch pipes are lapped at the joints of the steel pipe net frame, the lapped pipes are selected in a certain sequence, and in the K-shaped or N-shaped joint with gaps, the gaps of the branch pipes are not smaller than the sum of the wall thicknesses of the two branch pipes. In the overlapping K-shaped or N-shaped joint, for example, the overlap ratio should satisfy 25% to less than or equal to O v to less than or equal to 100%, and the joint weld between the branch pipes of the overlap should be ensured to reliably transmit the internal force.
In summary, the above factors and the plane truss structures of the buoyant raft in the transverse direction and the longitudinal direction are different, the two-way plane truss structures are respectively designed, the structural forms of the longitudinal plane truss structure 13 and the transverse plane truss structure 12 which are preliminarily designed are respectively shown in fig. 4 and 5, wherein the node types are lap joint K-shaped, T-shaped and plane KT-shaped, and the node types are respectively 1, 2 and 3 nodes in fig. 6. The horizontal grid structure is a strengthening material with the strength being connected, and the design of the horizontal grid structure can be designed by referring to the deck structure of steel sea vessel entering and building standard of China class society.
S1.5 design load determination
For rod piece design, for the initially designed planar net rack (i.e. planar truss structure), the section strength, stability, rigidity and nodes of the net rack rod piece need to meet the calculation requirements in the standard, and when the calculation requirements are checked, the planar net rack load design should be carried out. In a static state, the net rack bears the weight of the upper panel 21 and equipment and personnel on the upper panel 21. Therefore, the dead load of the planar net frame is designed according to the upper panel 21 and the weight of the equipment and personnel on the upper panel 21. The weight statistics of the equipment and personnel on the upper panel 21 are shown in table 1, the main equipment arrangement of the upper layer is shown in fig. 7 (equipment E is numerous and distributed scattered, the mass is much smaller than other structures and is omitted in fig. 7), the weight of the upper panel 21 is used as load input, the load action of the upper panel 21 and the equipment weight is recorded as constant load, and the load action of the personnel weight is recorded as live load. It is assumed that the weight is carried by the grid structure in the raft and the weight is reduced to an equivalent load acting on the nodes of the chords on the grid structure.
Table 1 upper layer preliminary design equipment and personnel weight table
| Device name | Weight (kg) | Quantity of | Total of kg |
| Personnel (personnel) | 75 | 20 | 1500 |
| Device A | 200 | 5 | 1000 |
| Device B | 500 | 1 | 500 |
| Device C | 500 | 1 | 500 |
| Device D | 200 | 5 | 1000 |
| Equipment E | 23 | 14 | 322 |
| Device F | 180 | 3 | 540 |
| Device G | 208 | 3 | 624 |
| Device H | 178 | 2 | 356 |
| Device I | 186 | 2 | 372 |
The constant load born by the grid structure is 11.024t, and the live load is 1.5t. In order to ensure the safety and reliability of the structure, the safety coefficient of the general building structure design takes the value K=1.5, but in order to ensure the safety coefficient of the raft structure different from the general building structure, the safety coefficient takes the value K=2.0 during checking. The loads on each side of the planar grid structure are shown in table 2 below.
Table 2 Single sided grid structure load (Unit: kN)
| Constant load | Live load | K constant load | K.times.live load | |
| Longitudinal plane net rack | 36.00 | 4.32 | 72.00 | 8.64 |
| Transverse plane net rack | 26.48 | 3.18 | 52.96 | 6.35 |
Checking the stress of the plane net rack:
after the design load is determined, the section strength, stability, rigidity and nodes of the net rack rod piece are calculated, checked and analyzed.
For the axial tension member, when the end connection and the middle splice form the plates with the section directly transferring force by the connecting piece, the section strength calculation meets the following regulations:
in addition to the high strength bolt friction type connector, the section strength thereof should be calculated using the following formula (1) and formula (2):
Mao Jiemian yield:
net cross section fracture:
wherein: n-design value of the tension at the calculated section (N)
F-design value of tensile Strength of Steel (N/mm 2)
A-wool cross-sectional area of the component (mm 2)
A n -the net cross-sectional area of the component, when multiple cross-sections of the component are perforated, the most disadvantageous cross-section (mm 2) is taken
F u -minimum design for tensile strength of steel (N/mm 2)
For the axial compression component, when the plates of which the sections are formed at the joints of the end parts and the middle parts are directly transmitted by the connecting piece, the section strength is calculated according to the formula (1), and the component containing the virtual hole is calculated according to the formula (2) at the section of the hole center. The checking standard is calculated based on the axle center stress component of the seventh chapter of the national standard steel structure design Standard (GB 50017-2017).
And checking the stability of members such as chord members, web members and the like in the net rack according to the axle center stress members according to national standard steel structure design standards (GB 50017-2017). The initial defect of the component is considered in the standard formula, and certain plastic development of the section is allowed. Except for solid-web components which can consider post-yield strength, the axial compression component adopts formula (3) to calculate stability:
wherein: n, the axial stress of the rod piece;
A f -rod cross-sectional area;
-the stability factor of the axial compression member (the smaller of the two principal axis stability factors of the section is taken). Stability factor The method is obtained according to the slenderness ratio (or converted slenderness ratio) of the components, the yield strength of steel and the section classification of the axial core compression component in the seventh chapter of steel structure design standard (GB 50017-2017).
In the design of the planar net frame, a method for limiting the slenderness ratio of a component is adopted to ensure the structural rigidity, and according to steel structural design standards (GB 50017-2017), the component adopts a formula (4) to calculate the rigidity:
Wherein: l-calculating the length of the rod piece;
r—the effective radius of gyration of the rod member;
[ lambda ] -the rod permits a slenderness ratio.
The safety of the node is mainly determined by the strength and the rigidity of the node, and the node failure caused by cracking of the joint parts such as welding lines, bolts and the like or the redistribution of the internal force caused by overlarge deformation of the node is prevented. There are different design verification requirements for different node forms. When checking, firstly, the requirement that the axial force of the component is not more than the design value of the bearing capacity is met, then, the node can be checked according to the design requirement in the node design part, and when checking, the calculation can be performed by referring to the specified formulas in chapters 12 and 13 in the steel structure design standard (GB 50017-2017).
S2, structural design of plate
S2.1 determination of sheet Material
For the design of the plate structure, 16Mn steel, Q235, Q345, Q390, Q420 and Q460 steel are preferably adopted, and can be specifically selected according to actual needs, and the quality of the steel meets the specifications of the current national standards of carbon structural steel GB/T700 and low alloy high strength structural steel GB/T1591 respectively. For a structure bearing vibration or impact and other dynamic loads, the standard requirements of GB 712-2011 structural steel for ships and ocean engineering can be referred to in selection, and high-strength steel with enough ductility and toughness can be selected to meet the bearing requirements. The present example selected Q345 steel for further analysis.
S2.2 Panel design
When the panel is designed, the design is carried out according to the size of the space where the structure is located, so that on one hand, the whole weight control of the floating raft is required to be met, and on the other hand, the design requirement under the action of load is required to be met. When designing, the maximum bending stress and the maximum deflection value of the panel under the effect of the design load are required to be calculated, so that the requirement of being smaller than the design value is met. The calculation model in calculation can be simplified into a rectangular plate with equal thickness and simple four sides, and the rectangular plate is uniformly distributed with load. The maximum bending stress value is calculated according to formula (5):
Wherein the formula is: alpha-calculating coefficients;
b-panel width;
t-panel thickness;
q-designing uniform load;
[ sigma ] -allowable stress value.
The maximum deflection is calculated according to the formula (6):
wherein: beta-calculating coefficients;
b-panel width;
t-panel thickness;
E-elastic modulus;
q-designing uniform load;
[ omega ] -deflection control value.
The thickness of the upper panel and the lower panel is 12mm after calculation.
S2.3 bulkhead design
The bulkhead of the net frame box body floating raft structure is mainly designed by adopting a plane bulkhead formed by strengthening materials and bulkhead plates, and the bulkhead in the raft structure is mainly used for separating cabins or is arranged due to strength requirements, so that a water bulkhead is not required. The arrangement and the number of the bulkheads are determined according to the division of the internal space of the raft frame, and longitudinal bulkheads, transverse bulkheads or half bulkheads are selected at proper positions to realize uniform arrangement. The number of bulkheads is reduced as much as possible under the condition of meeting the requirement of strength design. The thickness of the bilge plate and the size of the stiffening material can be designed according to the following calculation requirements by referring to steel sea ship entry level and construction Specification:
The bulkhead sheet thickness t should be not smaller than the value calculated by the formula (7):
Wherein: K. c-coefficients, selected according to Table 3;
s, spacing between strengthening materials, m;
h-the vertical distance from the lower edge of the bulkhead to the top of the bulkhead (the deep bulkhead is additionally 0.5 m), m;
table 3 coefficient K, c values
| Bulkhead type | Anti-collision bulkhead | Storage cabin wall | Deep cabin wall |
| K | 4.0 | 3.2 | 4.2 |
| c | 0.5 | 0 | 1.0 |
The bulkhead reinforcement is generally vertically arranged and has a section modulus W not less than that calculated by equation (8)
W＝Kshl2 cm3 (8)
Wherein: k-coefficient, selected according to Table 4;
s, spacing between strengthening materials, m;
h, a vertical distance from the middle point of the strengthening material to the top end of the bulkhead (0.5 mm is added to the deep cabin wall), and m;
l, the span of the strengthening material, m, the length of the strengthening material including the toggle plate is taken.
Table 4 value of the reinforcing material coefficient K of the planar bulkhead
The final bulkhead design is shown in figure 1, with a bulkhead in the middle of the longitudinal and transverse directions of the entire raft, and a short transverse bulkhead below the devices F and G.
And combining the designed planar grid structure with the plate frame structure to form a typical grid type box body floating raft structure. The thickness of the upper panel and the lower panel is 12mm, the overall weight of the net rack type floating raft is 23.84t, and the net rack type floating raft is almost equal to the plate rack type floating raft (23.95 t).
S3, integral checking and calculating of net frame type box body floating raft structure
The method comprises the steps of carrying out static checking on the whole floating raft, including checking in positive floating and inclined states, wherein the maximum stress of the structure in the two states is smaller than the yield stress of the material; vibration isolation checking is carried out on the whole floating raft, and the vibration isolation capability of the designed net rack floating raft in the full frequency band is larger than that of the traditional plate rack floating raft under the same weight.
Taking a positive floating state as an example, static force checking is carried out on the whole raft frame and the upper and lower panels, and the inclination and swinging quasi-static analysis is the same. Analyzing whether static response of designed grid type box body buoyant raft and traditional plate type buoyant raft in the forward floating state meets design requirements or not. The method is characterized in that fixed constraint boundary conditions are adopted on two sides of the lower boundary of the whole model, and the freedom degree of the model in six directions is limited. In the calculation, only the weight of the equipment and the raft frame itself is considered, and the model is subjected to calculation of a gravitational field (gravitational acceleration gy=9810 mm/s 2). The calculation results are shown in table 5, and the final results show that the static response performance of the grid-type buoyant raft in the forward floating state is superior to that of the traditional grid-type buoyant raft.
And (3) carrying out vibration isolation checking analysis on the whole net rack type box body buoyant raft structure according to the net rack type box body buoyant raft structure design flow. And a finite element model established by adopting ABAQUS is imported into VA one calculation software, and finally calculation results under different frequency bands are obtained, as shown in figure 8. Finally, the vibration level drop curves of the two structures show that the vibration isolation effect of the net rack type floating raft is better than that of the plate rack type floating raft.
TABLE 5 maximum stress and maximum displacement values of each structure of the raft in the forward floating state
If necessary, dynamic impact resistance check (namely dynamic check) is carried out on the floating raft structure, and the stress response of the structure under the action of environmental impact should meet the structural strength requirement.
The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present invention and the scope of the claims, which are to be protected by the present invention.
Claims (5)
1. The design method of the grid-type box body floating raft structure comprises a grid structure, an upper panel, a lower panel and a bulkhead; the grid structure is a space three-dimensional frame structure formed by a transverse, longitudinal and horizontal plane truss structure; the plane truss structure is a hollow lattice type flexural member formed by connecting rod pieces, and the rod pieces comprise chord members and web members; the upper panel is arranged on the upper surface of the horizontal plane truss at the top, and the lower panel is arranged on the upper surface of the horizontal plane truss at the bottom; the bulkhead is arranged in the grid structure and connected with the upper panel and/or the lower panel, and the bulkhead adopts a plane bulkhead formed by a stiffening material and a bulkhead plate; the design method is characterized by comprising the following steps of:
S1, designing a grid structure, comprising
S1.1, selecting a proper material based on the action of each rod piece on the grid structure;
S1.2, designing a grid structure type based on a vibration isolation design target, wherein the design comprises the steps of determining a plane truss structure type, a grid height and a grid size; the planar truss structure comprises a prasux truss, a wale truss, a feng truss and an arch truss;
S1.3, designing parameters including rod length, section form and slenderness ratio of the rod piece according to the determined grid structure type;
S1.4, carrying out node design based on the determined rod piece, wherein the node type comprises lap joint K shape, T shape and plane KT shape; the joint of the welded branch pipe and the main pipe is prevented from being eccentric, and if the eccentric cannot be avoided, the value of the joint does not exceed the limit of the following formula:
-0.55.ltoreq.e/D or e/h.ltoreq.0.25
Wherein e is the eccentricity;
D, the outer diameter of the circular tube main pipe;
h, the section height of the rectangular pipe main pipe in the connecting plane;
When a plurality of branch pipes are lapped at the joints of the steel pipe net frame, the lapped pipes are selected in a certain sequence, and in the K-shaped or N-shaped joint with gaps, the gaps of the branch pipes are not smaller than the sum of the wall thicknesses of the two branch pipes; in the overlapped K-shaped or N-shaped node, the overlap ratio O v is more than or equal to 25% and less than or equal to 100% O v, and the connection welding seam between the branch pipes of the overlapped part is ensured to reliably transmit internal force;
S1.5, carrying out load design of the planar truss structure according to the actual use environment of the grid structure, wherein the load comprises a permanent load and a variable load; for the plane truss structure, according to the designed load, carrying out cross-section strength, stability, rigidity and node check of the plane truss structure based on internal force analysis;
s2, designing a plate, comprising
S2.1, selecting proper materials according to the application of the plate and the load born by the plate, wherein the plate comprises an upper panel, a lower panel and a bulkhead;
s2.2, designing the panel, wherein the maximum bending stress and deflection value of the designed panel are smaller than the allowable value in consideration of the weight of equipment on the panel;
The maximum bending stress value is calculated according to formula (5):
In the formula, alpha is a calculation coefficient;
b-panel width;
t-panel thickness;
q-designing uniform load;
[ sigma ] -allowable stress value;
The maximum deflection is calculated according to the formula (6):
wherein: beta-calculating coefficients;
b-panel width;
t-panel thickness;
E-elastic modulus;
q-designing uniform load;
[ omega ] -deflection control value;
S2.3, designing the bulkhead, including designing the thickness of the bulkhead plate and the size of the stiffening material, and arranging and number of the bulkheads; the thickness of the bulkhead plate and the section modulus of the stiffening material meet the standard requirements; the arrangement and the number of the bulkheads are divided by the internal space of the floating raft, and longitudinal bulkheads, transverse bulkheads or half bulkheads are selected at proper positions;
The bulkhead sheet thickness t should be not smaller than the value calculated by the formula (7):
Wherein: K. c-coefficients, selected according to Table 3;
s, spacing between strengthening materials, m;
h, the vertical distance from the lower edge of the bulkhead to the top end of the bulkhead, m; the wall of the deep cabin is additionally added with 0.5m;
table 3 coefficient K, c values
The bulkhead reinforcement is vertically arranged, and the section modulus W of the bulkhead reinforcement is not smaller than the value calculated according to the formula (8)
W＝Kshl2 cm3 (8)
Wherein: k-coefficient, selected according to Table 4;
s, spacing between strengthening materials, m;
h, the vertical distance from the midpoint of the strengthening material to the top end of the bulkhead, m; adding 0.5mm to the wall of the deep cabin;
l, the span of the strengthening material, m, taking the length of the strengthening material including a toggle plate;
Table 4 value of the reinforcing material coefficient K of the planar bulkhead
S3, integral check of the buoyant raft, which comprises
Static checking is carried out on the whole floating raft, including checking in forward floating and inclined states, and the maximum stress of the structure in the two states is smaller than the yield stress of the material;
vibration isolation checking is carried out on the whole floating raft, and the vibration isolation capability of the designed net rack floating raft in the full frequency band is larger than that of the traditional plate rack floating raft under the same weight.
2. The method for designing a net cage floating raft structure according to claim 1, wherein the selection range of the rod material and the plate material is: 16Mn steel, Q235, Q345, Q390, Q420, Q460 steel.
3. The method for designing a floating raft structure of a net frame type box body according to claim 1, wherein in the step S3, the whole checking of the floating raft further comprises performing impact resistance checking on the floating raft structure, and the stress response of the structure under the effect of environmental impact should meet the structural strength requirement.
4. The method for designing a floating raft structure of a net frame type box body according to claim 1, wherein the net frame structure, the upper panel, the lower panel and the bulkhead are connected in a welding mode.
5. The method of designing a lattice framed box raft structure of claim 1, wherein the lattice framed box raft structure doubles as a ship cabin.
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Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN86103393A (en) * | 1985-05-17 | 1986-11-12 | 布隆福斯造船公司 | Catamaran |
| US6142090A (en) * | 1998-10-07 | 2000-11-07 | Electric Boat Corporation | Power converter arrangement for integration into a ship structure |
| CN1582240A (en) * | 2001-10-16 | 2005-02-16 | 马太及肖特工程师公司 | Ship with composite structure |
| CN201457700U (en) * | 2009-08-06 | 2010-05-12 | 天津天易海上工程有限公司 | Bottom mounted pipe-laying ship |
| CN105667705A (en) * | 2016-03-18 | 2016-06-15 | 江苏科技大学 | Ship cabin with bulkhead capable of loading mass in line connecting position |
| CN106741674A (en) * | 2015-11-20 | 2017-05-31 | 中国舰船研究设计中心 | A kind of ice breaker iceproof Double-skinned structure at tank stabilizer |
| CN206569221U (en) * | 2017-03-17 | 2017-10-20 | 上海船舶研究设计院（中国船舶工业集团公司第六0四研究院） | A kind of bulkhead structure in main hull |
| CN110987345A (en) * | 2019-12-13 | 2020-04-10 | 中国人民解放军海军工程大学 | Performance optimization detection test bed for ship buoyant raft vibration isolation system |
| CN111532403A (en) * | 2020-05-15 | 2020-08-14 | 中国科学院声学研究所 | Formula cabin raft is embraced in sinking |
| CN113895559A (en) * | 2021-09-29 | 2022-01-07 | 广船国际有限公司 | Ship structure reinforcement and ship manufacturing method |
| CN113911308A (en) * | 2021-10-26 | 2022-01-11 | 湖北宜昌精森机械有限公司 | Raft frame of power cabin raft of ship |
-
2022
- 2022-06-09 CN CN202210649897.5A patent/CN114919710B/en active Active
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN86103393A (en) * | 1985-05-17 | 1986-11-12 | 布隆福斯造船公司 | Catamaran |
| US4766829A (en) * | 1985-05-17 | 1988-08-30 | Blohm + Voss Ag | Catamaran-type marine craft |
| US6142090A (en) * | 1998-10-07 | 2000-11-07 | Electric Boat Corporation | Power converter arrangement for integration into a ship structure |
| CN1582240A (en) * | 2001-10-16 | 2005-02-16 | 马太及肖特工程师公司 | Ship with composite structure |
| CN201457700U (en) * | 2009-08-06 | 2010-05-12 | 天津天易海上工程有限公司 | Bottom mounted pipe-laying ship |
| CN106741674A (en) * | 2015-11-20 | 2017-05-31 | 中国舰船研究设计中心 | A kind of ice breaker iceproof Double-skinned structure at tank stabilizer |
| CN105667705A (en) * | 2016-03-18 | 2016-06-15 | 江苏科技大学 | Ship cabin with bulkhead capable of loading mass in line connecting position |
| CN206569221U (en) * | 2017-03-17 | 2017-10-20 | 上海船舶研究设计院（中国船舶工业集团公司第六0四研究院） | A kind of bulkhead structure in main hull |
| CN110987345A (en) * | 2019-12-13 | 2020-04-10 | 中国人民解放军海军工程大学 | Performance optimization detection test bed for ship buoyant raft vibration isolation system |
| CN111532403A (en) * | 2020-05-15 | 2020-08-14 | 中国科学院声学研究所 | Formula cabin raft is embraced in sinking |
| CN113895559A (en) * | 2021-09-29 | 2022-01-07 | 广船国际有限公司 | Ship structure reinforcement and ship manufacturing method |
| CN113911308A (en) * | 2021-10-26 | 2022-01-11 | 湖北宜昌精森机械有限公司 | Raft frame of power cabin raft of ship |
Non-Patent Citations (3)
| Title |
|---|
| 《中国造船质量标准》（CSQS）与《船舶建造与修理质量标准》（Rec.47）对比分析研究;刘伟;李天煜;曾红莉;匡文琪;;船舶标准化与质量;20191031(第05期);全文 * |
| 新型桁架箱体浮筏结构重量优化研究;王壮 等;舰船科学技术;43(2);40-43 * |
| 杨睿 等.舰艇浮筏隔振系统的发展与趋势.船舶工程.2020,(7),N18-N24. * |
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