A verification and evaluation method for column ring plate joints

Abstract

The present invention discloses a column ring plate node verification and evaluation method, which relates to the technical field of column ring plate node verification. The method comprises the following steps: S1, extracting the member loads of the relevant members of the offshore platform column ring plate node under various working conditions; S2, for the convenience of calculation, decomposing the column ring plate node into upper and lower ring plate nodes and calculating their cross-sectional properties respectively; S3, according to the load conditions of each structural member at the node and the stress characteristics of the steel section, the axial load of each member is evenly divided into the axial loads on the upper ring plate and the lower ring plate; S4, according to the stress characteristics of the steel section, the in-plane bending load of each member is converted into the axial force on the upper ring plate and the lower ring plate. The present invention can realize the accurate evaluation of the force of the column ring plate node by means of load superposition, thereby avoiding the deficiency of the existing engineering software in the verification of the column ring plate node. Compared with the finite element method, it can save a lot of evaluation time and simplify the evaluation work.

Description

Technical Field

[0001] The present invention relates to the technical field of column ring plate node verification, and in particular to a column ring plate node verification and evaluation method. Background Art

[0002] Offshore platforms are a common structural form used for offshore oil and gas extraction and processing. Their upper modules are space frame structures composed of a plate-beam structure, used to support production and living equipment and facilities. The column-ring plate node is a node composed of the main deck frame beams, platform columns, and corresponding reinforcing ring plates. It is used to transfer loads between the frame beams and columns and plays a vital role in the structural safety of offshore platforms. Therefore, evaluating the strength of the column-ring plate node is of great significance to the safety of the module structure.

[0003] In actual engineering, existing engineering software uses rod units to simulate frame beams and columns, and it is impossible to achieve effective evaluation of such nodes in the software. If the finite element method is used, it is necessary to model and load according to different design conditions, and perform corresponding calculation analysis and result evaluation. The corresponding design workload is large and the technical solution is complex, which is not conducive to engineering implementation. Therefore, the applicant proposes a method to solve the above-mentioned problems. Summary of the Invention

[0004] The object of the present invention is to provide a column ring plate node verification and evaluation method to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a column ring plate node verification and evaluation method, comprising the following steps:

[0006] S1. Extract the member loads of the relevant members of the offshore platform column ring plate node under various working conditions;

[0007] S2. To facilitate calculation, the column ring plate node is decomposed into upper and lower ring plate nodes and their cross-sectional properties are calculated separately.

[0008] S3. Based on the load conditions of each structural member at the node and the stress characteristics of the steel section, the axial load of each member is evenly divided into the axial loads on the upper ring plate and the lower ring plate;

[0009] S4. According to the stress characteristics of the steel section, the in-plane bending load of each member is converted into axial force on the upper and lower ring plates;

[0010] S5. Based on the stress characteristics of the steel section, the out-of-plane bending load of each member is evenly divided into the torsional load on the upper and lower ring plates;

[0011] S6. Combine the loads in S3 and S4 to obtain the comprehensive axial loads of the relevant members of the upper and lower ring plate nodes;

[0012] S7. Substitute the comprehensive axial load obtained in S6 into the ring plate node stress calculation formula to obtain the stress of the column ring plate node under the axial load;

[0013] S8. Substitute the torsional load obtained in S5 into the ring plate node stress calculation formula to obtain the stress of the column ring plate node under the torsional load;

[0014] S9. Superimpose the node stresses obtained in S7 and S8 to obtain the comprehensive stress conditions of the upper and lower ring plate nodes respectively; compare the stress with the allowable stress of the node steel to obtain the verification and evaluation results of the column ring plate node.

[0015] Furthermore, the working conditions mentioned in step S1 include in-situ working conditions and installation working conditions, wherein the in-situ working conditions are one or more combinations of static, earthquake and collapse, and the installation working conditions are one or more combinations of loading, towing and lifting.

[0016] Furthermore, the column ring plate node mentioned in step S2 is divided into an upper and lower ring plate, and a spacing is left between the upper and lower ring plates so as not to affect each other.

[0017] Furthermore, the axial load on the web fixed to the outside of the rod mentioned in step S3 is also converted to the two layers of annular plates and combined with the axial load of the two layers of annular plates.

[0018] Furthermore, the two ring plates mentioned in step S4 generate axial tension / compression forces of equal magnitude and opposite directions according to different bending load directions.

[0019] Furthermore, the comprehensive axial load mentioned in step S6 may be superimposed or offset depending on the specific working conditions.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This column-ring-plate node verification and evaluation method can achieve accurate evaluation of the column-ring-plate node forces through load superposition, thereby avoiding the shortcomings of existing engineering software in the verification of column-ring-plate nodes. Compared with the finite element method, it can greatly save evaluation time and simplify the evaluation work.

[0022] This column-ring-plate node verification and assessment method uses specifications to verify the strength of the upper module under in-situ working conditions after considering the influence of settlement, and completes the impact assessment. If the assessment results fail to meet the design specifications, feedback is provided to the design unit, and adjustments and reinforcements are made to the corresponding structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1Schematic diagram of column ring plate node;

[0024] Figure 2 Schematic diagram of the upper and lower ring plates;

[0025] Figure 3 It is a top view of the combination of column and ring plate;

[0026] Figure 4 Schematic diagram of the cross section of the column and ring plate combination;

[0027] Figure 5 The force analysis diagram of column ring plate linear load and concentrated load;

[0028] Figure 6 This is the force analysis diagram of the concentrated load on the column ring plate;

[0029] Figure 7 This is the force analysis diagram of the column ring plate under torsional load;

[0030] Figure 8 Flowchart of the evaluation methodology for this application.

[0031] In the figure: 11, column; 12, upper ring plate; 13, lower ring plate; 14, beam web; 15, upper and lower ring plates; 21, action of line load and concentrated load; 22, action of concentrated load; 23, action of torsional load. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] It should be noted that, in the description of the present invention, the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply 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 on the present invention.

[0034] Furthermore, it should be understood that for the sake of ease of description, the sizes of the various components shown in the drawings are not drawn according to actual proportions. For example, the thickness or width of certain layers may be exaggerated relative to other layers.

[0035] It should be noted that like numbers and letters represent similar items in the following figures, so once an item is defined or described in one figure, it will not need to be further discussed and described in detail in the description of the subsequent figures.

[0036] In actual engineering, existing engineering software uses rod units to simulate frame beams and columns 11, and it is impossible to achieve effective evaluation of such nodes in the software. If the finite element method is used, it is necessary to model and load according to different design conditions, and perform corresponding calculation analysis and result evaluation. The corresponding design workload is large and the technical solution is complex, which is not conducive to engineering implementation. Therefore, the applicant proposes a method to solve the above-mentioned problems.

[0037] like Figure 1 - Figure 7 As shown, the present invention provides a technical solution:

[0038] S1, extract the ring plate nodes of the offshore platform column 11 (such as Figure 1 Member loads of relevant members under various working conditions (in position and installed) are shown.

[0039] It should be noted that the calculation conditions of the offshore platform in this application usually include in-situ conditions (static, earthquake, collapse) and installation conditions (shipping, towing, lifting). The node-related member loads under all conditions need to be extracted to avoid omissions.

[0040] S2. To facilitate calculation, the column 11 ring plate node is decomposed into upper and lower ring plate 15 nodes.

[0041] Among them Figure 4 As shown, their cross-sectional properties are calculated separately. In addition, the ring plate node of the column 11 is divided into the upper and lower ring plates 15. Since the distance between them is large and the influence between them is small, decomposing them can better reflect the load conditions of the upper and lower ring plates 15.

[0042] S3, according to the load conditions of each structural member at the node and the steel section (such as Figure 1 According to the stress characteristics of the rod (as shown), the axial load of each rod is evenly divided into the axial loads on the upper ring plate 12 and the lower ring plate 13; the axial load borne by the beam web 14 in the rod is also converted to the upper and lower ring plates 15 and combined with the axial loads of the upper and lower ring plates 15.

[0043] S4, according to the steel section (such as Figure 1 The force characteristics of the rods are converted into axial forces on the upper ring plate 12 and the lower ring plate 13.

[0044] It should be noted that, in the present application, according to different bending load directions, the upper and lower ring plates 15 will respectively generate axial tension / compression forces of equal magnitude and opposite directions.

[0045] S5, according to the steel section (such as Figure 1 According to the stress characteristics of the upper ring plate 12 and the lower ring plate 13, the out-of-plane bending load of each rod is evenly divided into the torsional load.

[0046] S6. Combine the loads in S3 and S4 to obtain the comprehensive axial loads of the relevant rods at the 15 nodes of the upper and lower ring plates.

[0047] It should be noted that in this application, the axial loads contained in S3 and S4 may be superimposed or offset according to specific working conditions, and need to be combined according to different working conditions to obtain the linear load and concentrated load effects 21.

[0048] S7. Substitute the comprehensive axial load obtained in S6 into the ring plate node stress calculation formula to obtain the stress of the ring plate node of the column 11 under the action of the axial concentrated load 22.

[0049] S8. Substitute the torsional load obtained in S5 into the ring plate node stress calculation formula to obtain the stress of the ring plate node of column 11 under the torsional load.

[0050] S9. Superimpose the node stresses obtained in S7 and S8 to obtain the comprehensive stress conditions of the upper and lower ring plate 15 nodes respectively; compare the stress with the allowable stress of the node steel to obtain the verification and evaluation results of the column 11 ring plate node.

[0051] It should be emphasized that this application can achieve accurate evaluation of the force on the column 11 ring plate node through load superposition, thereby avoiding the shortcomings of existing engineering software in the verification of the column 11 ring plate node. Compared with the finite element method, it can save a lot of evaluation time and simplify the evaluation work.

[0052] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A column ring plate joint verification and evaluation method, characterized by: The evaluation method comprises the following steps: S1. Extract the member loads of the relevant members of the offshore platform column ring plate node under various working conditions; S2. To facilitate calculation, the column ring plate node is decomposed into upper and lower ring plate nodes and their cross-sectional properties are calculated separately. S3. Based on the load conditions of each structural member at the node and the stress characteristics of the steel section, the axial load of each member is evenly divided into the axial loads on the upper ring plate and the lower ring plate; S4. According to the stress characteristics of the steel section, the in-plane bending load of each member is converted into axial force on the upper and lower ring plates; S5. Based on the stress characteristics of the steel section, the out-of-plane bending load of each member is evenly divided into the torsional load on the upper and lower ring plates; S6. Combine the loads in S3 and S4 to obtain the comprehensive axial loads of the relevant members of the upper and lower ring plate nodes; S7. Substitute the comprehensive axial load obtained in S6 into the ring plate node stress calculation formula to obtain the stress of the column ring plate node under the axial load; S8. Substitute the torsional load obtained in S5 into the ring plate node stress calculation formula to obtain the stress of the column ring plate node under the torsional load; S9. Superimpose the node stresses obtained in S7 and S8 to obtain the comprehensive stress conditions of the upper and lower ring plate nodes respectively; compare the stress with the allowable stress of the node steel to obtain the verification and evaluation results of the column ring plate node.

2. The column ring plate joint verification and evaluation method according to claim 1 is characterized in that: The working conditions mentioned in step S1 include in-situ working conditions and installation working conditions, wherein the in-situ working conditions are one or more combinations of static, earthquake and collapse, and the installation working conditions are one or more combinations of loading, towing and lifting.

3. The column ring plate joint verification and evaluation method according to claim 1 is characterized in that: The column ring plate node mentioned in step S2 is divided into an upper and lower ring plate, and a gap is left between the upper and lower ring plates so as not to affect each other.

4. The column ring plate joint verification and evaluation method according to claim 3 is characterized in that: The axial load on the web fixed to the outside of the rod mentioned in step S3 is also converted to the two layers of annular plates and combined with the axial load of the two layers of annular plates.

5. The column ring plate joint verification and evaluation method according to claim 1 is characterized in that: The two ring plates mentioned in step S4 generate axial tension / compression forces of equal magnitude and opposite directions according to different bending load directions.

6. The column ring plate joint verification and evaluation method according to claim 1 is characterized in that: The comprehensive axial load mentioned in step S6 may be superimposed or offset according to specific working conditions.

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