A Design Method for Parametric Nodes of Offshore Substations

Abstract

The present invention relates to the technical field of offshore engineering structure design, and discloses a design method for a parametric node of an offshore substation, including the following steps: S1. Find out the most important preset working conditions according to the structural calculation results; S2. Determine the thickness of the flange plate in the node area; S3. Intercept a horizontal section of a diagonal brace from the substation model set in the preset working condition, and obtain the axial force F and bending moment M on this horizontal section; S4. Make the thickness of the web connection plate equal to the thickness of the adjacent section steel, assuming that there are n gussets, and the distance between two adjacent gussets is d; S5. Assume that the angle a between the diagonal brace and the beam is 30°, 45° or 60°, and calculate the strength of the node at the three angles in turn according to the parameters in step S4; When the number of a group of gussets and reducing the distance d between two adjacent gussets meet the strength requirements of the node at the three angles, the design of the node is completed. The present invention has the advantages of high design efficiency, few node drawings and stable structure.

Description

Technical Field

[0001] The present invention relates to the field of offshore engineering structure design, and particularly to a design method for parametric joints of an offshore booster station. Background Art

[0002] The upper module joints of an offshore booster station are mainly composed of H-shaped steel and steel pipes. The joint strength of the offshore booster station is crucial. In traditional offshore engineering, for the design of each joint, the number and thickness of gusset plates of the joint need to be designed according to the thickness of the H-shaped steel plate in each joint area, the internal force and angle of the steel pipe, and the thickness of the steel pipe plate for each working condition. Then, the maximum gusset plate thickness and the number of gusset plates are selected according to the envelope principle, and then the joint drawing is drawn to complete the design of the joint. However, there are generally dozens of main joints in the offshore booster station, which is completely mechanical and repetitive work with a huge amount of work. The design and manufacture of joints generally take about 2 months, requiring a large number of designers and design time, seriously affecting production modeling, material procurement and project progress; and there will also be phenomena such as joint mismatch and drawing modification. Figure 1 Generally, it takes about 2 months, requiring a large number of designers and design time, seriously affecting production modeling, material procurement and project progress; and there will also be phenomena such as joint mismatch and drawing modification. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a design method for parametric joints of an offshore booster station with high design efficiency, few joint drawings and stable structure.

[0004] To solve the above technical problem, the present invention provides a design method for parametric joints of an offshore booster station. A plurality of beams intersect to form a joint structure. At least one diagonal brace is provided on the beam. The joint structure includes gusset plates, web connection plates, flange plates, a plurality of steel sections and at least one diagonal brace, and includes the following steps:

[0005] S1. Find the most important preset working condition according to the structural calculation results;

[0006] S2. Determine the thickness of the flange plate in the joint area, and select the maximum value from the thickness values of a plurality of steel sections as the thickness of the flange plate;

[0007] S3. Intercept a horizontal section of a diagonal brace from the booster station model set in the preset working condition, and obtain the axial force F and bending moment M on the horizontal section;

[0008] S4. Take the thickness of the web connection plate equal to the thickness of the adjacent steel section. Assume that there are n gusset plates, and the distance between two adjacent gusset plates is d;

[0009] S5. Respectively set the angle a between the diagonal brace and the beam to 30°, 45° and 60°, and calculate the total stress of the joint at the three angles in turn according to the total stress αtotal. αtotal = F / A + M / (A * L * 2), where A is the total contact area between the gusset plate and the diagonal brace, and L is the distance between the two end gusset plates;

[0010] S6. Compare the total stress with the allowable stress of the material:

[0011] If the total stress α is less than the allowable stress of the material, the strength requirement is met;

[0012] If the total stress α is greater than the allowable stress of the material, modify the parameters assumed in step S4, increase the number of gusset plates and reduce the distance d between two adjacent gusset plates, and then calculate the total stress according to steps S5.1 to S5.3 until the total stress is less than the allowable stress of the material;

[0013] When the parameters assumed in step S4 meet the strength requirements at the angles a of 30°, 45°, and 60° between the diagonal brace and the beam, the assumed parameters are the design parameters of the node, and the design of the node is completed.

[0014] As a preferred solution of the present invention, in step S1, the working conditions of the offshore booster station include offshore ship transportation working conditions, hoisting working conditions, earthquake working conditions, ship loading working conditions, and positioning working conditions. Calculate the structural strength safety values of the working conditions in sequence, and select the working condition with the largest structural strength safety value as the preset working condition.

[0015] As a preferred solution of the present invention, in step S2, when there are upper columns and lower columns at the intersection of multiple beams, select the maximum value from the thickness values of multiple steel sections, the diameter of the upper column, and the diameter of the lower column as the thickness of the flange plate.

[0016] As a preferred solution of the present invention, in step S4, make the distance between the gusset plate and the diagonal brace equal to the distance between two adjacent gusset plates.

[0017] As a preferred solution of the present invention, the specific calculation of step S5 is as follows;

[0018] S5.1. Calculate the contact stress α1 generated by the axial force F: α1 = F / A;

[0019] S5.2. Calculate the contact stress α2 generated by the bending moment M: α2 = M / (A * L * 2);

[0020] S5.3. Calculate the total stress α 总 : α 总 = α1 + α2.

[0021] As a preferred solution of the present invention, it further includes step S6, which is specifically as follows:

[0022] S6. Determine the arc transition radius of the flange plate, the aperture of the weld-through hole, and the welding requirements.

[0023] As a preferred solution of the present invention, it further includes step S7, which is specifically as follows:

[0024] S7. Summarize the parameters such as the thickness of the flange plate, the thickness of the web connection plate, the number of gussets, and the distance between two adjacent gussets determined in the above steps in a table.

[0025] Compared with the prior art, the beneficial effect of the design method of the parametric joint of the offshore booster station in the embodiment of the present invention lies in:

[0026] After the joint is designed once in the present invention, the joint parameters can be set as standard parameters, and the joints in other positions can directly use these parameters, thereby greatly reducing the drawing time of the main structure of the booster station, greatly reducing the workload of the structural designers, improving the design efficiency, reducing the number of joint drawings, reducing the workload of the drawing viewers, and also reducing the inconsistent situations such as joint mismatching and drawing modification caused by structural modification, ensuring the overall safety of the offshore booster station structure, and at the same time ensuring that the joints of the offshore booster station remain stable under different working conditions. Description of the Drawings

[0027] Figure 1 is a structural schematic diagram of a design method of a parametric joint of an offshore booster station provided by an embodiment of the present invention;

[0028] Figure 2 is Figure 1 the sectional view in the A-A direction in Detailed Embodiments

[0029] The following combines the drawings and embodiments to further describe in detail the specific embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0030] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. in the present invention is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0031] Such as Figure 1 and Figure 2As shown in the figure, a preferred embodiment of a design method for parametric nodes of an offshore booster station provided by the present invention. A node structure is formed by the intersection of multiple beams. There is at least one diagonal brace 1 on the beams. The node structure includes gusset plates 2, web connection plates 3, flange plates 4, multiple sections 5 and at least one diagonal brace 1. The structure of the node is an existing structure. In this embodiment, there are four beams, and there are upper diagonal braces 11 and lower diagonal braces 12 on each beam, including the following steps:

[0032] S1. Find the most important preset working conditions according to the structural calculation results;

[0033] S2. Determine the thickness of the flange plate 4 in the node area, and select the maximum value from the thickness values of multiple sections 5 as the thickness of the flange plate 4;

[0034] S3. Intercept a horizontal section of a diagonal brace 1 from the booster station model set in the preset working conditions, and obtain the axial force F and bending moment M on this horizontal section. Specifically, in the booster station model, it is known that the maximum envelope internal forces F1 and M1 of the upper diagonal brace 11 section and the maximum envelope internal forces F2 and M2 of the lower diagonal brace 12 section are shown in Table 1:

[0035] Table 1 Force table of partial section diagonal braces 1 of the offshore booster station in this embodiment

[0036]

[0037] S4. Take the thickness of the web connection plate 3 equal to the thickness of the adjacent section 5. Assume that there are n gusset plates 2, and the distance between two adjacent gusset plates 2 is d;

[0038] S5. Assume that the angle a between the diagonal brace 1 and the beam is 30°, 45° or 60°, and calculate the strength of the node at the three angles in turn according to the parameters in step S4. The calculation steps are as follows;

[0039] S5.1. Calculate the contact stress α1 generated by the axial force F: α1 = F / A, where A is the total contact area between the gusset plate 2 and the diagonal brace 1;

[0040] S5.2. Calculate the contact stress α2 generated by the bending moment M: α2 = M / (A*L*2), where L is the distance between the two end gusset plates 2;

[0041] S5.3. Calculate the total stress α 总 : α 总 = α1 + α2;

[0042] S5.4. If α 总 is less than the allowable stress of the material, the strength requirement is met;

[0043] If α 总If it is greater than the allowable stress of the material, modify the parameters assumed in step S4, increase the number of gusset plates 2 and reduce the distance d between two adjacent gusset plates 2, and then calculate the total stress according to steps S5.1 to S5.3 until the total stress is less than the allowable stress of the material;

[0044] When the number of a set of gusset plates 2 and the reduced distance d between two adjacent gusset plates 2 satisfy the strength at the nodes of the three included angles, the design of the nodes is completed;

[0045] S6. Determine the arc transition radius of the flange plate 4, the aperture of the through-welding hole and the welding requirements;

[0046] S7. Summarize the parameters such as the thickness of the flange plate 4, the thickness of the web connection plate 3, the number of gusset plates 2 and the distance between two adjacent gusset plates 2 determined in the above steps through a table; thus, by modeling according to the table parameters, the production modeling workload of the construction unit will not be increased, and if the structural design is modified, it is easier to modify the model. However, for the traditional repetitive step-by-step modeling design method, the modification workload is large and it is easy to make mistakes.

[0047] After the nodes are designed once in the present invention, the node parameters can be set as standard parameters, and the nodes in other positions can directly use these parameters, thereby greatly reducing the drawing time of the main structure of the booster station, greatly reducing the workload of the structural designers, improving the design efficiency, reducing the number of node drawings, reducing the workload of the drawing viewers, and also reducing the inconsistent situations such as node mismatch and drawing modification caused by structural modification, ensuring the overall safety of the offshore booster station structure, and at the same time ensuring that the nodes of the offshore booster station remain stable under different working conditions.

[0048] Exemplarily, in step S1, the preset working conditions of the offshore booster station include the offshore ship transportation working condition, the hoisting working condition, the earthquake working condition, the ship loading working condition and the in-place working condition. Calculate the structural strength safety values of the working conditions in sequence, and select the working condition with the largest structural strength safety value as the most important preset working condition. In this embodiment, the offshore ship transportation working condition > the hoisting working condition > the earthquake working condition > the ship loading working condition > the in-place working condition. Therefore, the offshore ship transportation working condition is selected as the most important preset working condition, wherein the calculation method of the structural strength safety value is existing.

[0049] Exemplarily, in step S2, when there are upper columns 6 and lower columns 7 at the intersection of multiple beams, select the maximum value from the thickness values of multiple profiled steels 5, the diameter of the upper column 6 and the diameter of the lower column 7 as the thickness of the flange plate 4; thus, designers can adopt different data to obtain the thickness of the flange plate 4 according to different node structures, with a wide application range and strong practicability.

[0050] Exemplarily, in step S4, the distance between the gusset plate and the diagonal brace is made equal to the distance between two adjacent gusset plates, ensuring that the contact stress between the gusset plate and the diagonal brace is more uniform.

[0051] In the description of the present invention, it should be understood that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" used in the present invention should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0052] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A design method for parametric nodes of an offshore booster station, where multiple beams intersect to form a node structure, at least one diagonal brace is provided on the beams, and the node structure includes gusset plates, web connecting plates, flange plates, multiple sections steel, and at least one diagonal brace, characterized in that, The steps include: S1. Find the preset working condition according to the structural calculation results; S2. Select the maximum value from the thickness values ​​of multiple steel sections as the thickness of the flange plate; S3, cutting a horizontal section of a diagonal brace from the booster station model set in the preset working condition, and obtaining the axial force F and bending moment M on the horizontal section; S4. Take the thickness of the web connecting plate equal to the thickness of the adjacent steel section. Assume that there are n brackets and the distance between two adjacent brackets is d; S5. Set the angles a between the diagonal braces and the beam to 30°, 45°, and 60° respectively, and calculate the total stress α of the nodes at these three angles according to the total stress α 总 Calculate the total stress of the nodes at the three angles in sequence, α 总 = F / A + M / (A*L*2), where A is the total contact area between the gusset plate and the diagonal brace, and L is the distance between the gusset plates at both ends; S6. Compare the total stress with the allowable stress of the material: If α 总 is less than the allowable stress of the material, the strength requirement is met; If α 总 is greater than the allowable stress of the material, modify the parameters assumed in step S4, increase the number of gussets and reduce the distance d between two adjacent gussets, and then calculate the total stress according to step S5 until the total stress is less than the allowable stress of the material; When the parameters assumed in step S4 meet the strength requirements when the angle a between the brace and the beam is 30°, 45° and 60°, the assumed parameters are the design parameters of the node, and the design of the node is completed.

2. The design method of the parametric node of the offshore booster station according to claim 1, wherein In step S1, the working conditions of the offshore booster station include offshore ship transportation conditions, lifting conditions, earthquake conditions, loading conditions and situ conditions. The structural strength safety values ​​of the working conditions are calculated in turn, and the working condition with the largest structural strength safety value is selected as the preset working condition.

3. The design method of the parametric node of the offshore booster station according to claim 1, wherein, In step S2, when an upper column and a lower column are provided at the intersection of multiple beams, the maximum value is selected from the thickness values ​​of multiple steel sections, the diameter of the upper column and the diameter of the lower column as the thickness of the flange plate.

4. The design method of the parametric node of the offshore booster station according to claim 1, characterized in that, In step S4, the distance between the bracket and the diagonal brace is made equal to the distance between two adjacent brackets.

5. The design method of the parametric node of the offshore booster station according to claim 1, wherein, The specific calculation of step S5 is as follows: S5.

1. Calculate the contact stress α1 generated by the axial force F: α1 = F / A; S5.

2. Calculate the contact stress α2 generated by the bending moment M: α2 = M / (A*L*2); S5.

3. Calculate the total stress α 总 : α 总 = α1 + α2.

6. The design method of the parametric node of the offshore booster station according to claim 1, characterized in that, The step S6 is further included, which is as follows: S6. Determine the arc transition radius of the flange plate, the hole diameter of the weld hole and the welding requirements.

7. The design method of the parametric node of the offshore booster station according to claim 1, characterized in that, The step S7 is further included, which is as follows: S7. Summarize the parameters such as the thickness of the flange plate, the thickness of the web connecting plate, the number of brackets and the distance between two adjacent brackets determined in the above steps in a table.

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