CN-121980737-A - Offshore structure pipe node lightweight design method and system based on response surface method

CN121980737ACN 121980737 ACN121980737 ACN 121980737ACN-121980737-A

Abstract

The invention belongs to the technical field of offshore converter station construction design, and provides a response surface method-based offshore structure pipe node lightweight design method and system, wherein the minimum total weight of the structure pipe node is taken as a target, and an ultimate strength stress ratio is not more than a preset allowable value as a constraint condition, so as to establish an objective function; A series of test sample points are generated by Latin hypercube sampling, a structural response value corresponding to each sample point is extracted, a polynomial function is obtained by fitting a response surface method according to the structural response value, a lightweight design scheme is obtained according to the polynomial function, and the stress ratio response surface in a high-dimensional design space can be effectively fitted based on a sampled high-precision response surface model.

Inventors

CHEN CHANGBING
YANG CAN
HOU SHIJIN
DING XIAOQIANG
SUN XIAOHONG
LI XU
WANG YANQIANG
LIU CHANGBIN
CHEN JIE
SUN SHUZHENG
DONG YAN

Assignees

山东电力工程咨询院有限公司

Dates

Publication Date: 20260505
Application Date: 20251205

Claims (10)

1. The lightweight design method for the offshore structure pipe node based on the response surface method is characterized by comprising the following steps of: Establishing a target function by taking the minimum total weight of the structural pipe nodes as a target and taking the limit strength stress ratio not larger than a preset allowable value as a constraint condition; According to the three-dimensional entity model and the objective function, latin hypercube sampling is adopted to generate a series of test sample points; extracting a structural response value corresponding to each sample point; fitting by adopting a response surface method according to the structural response value to obtain a polynomial function; And obtaining a lightweight design scheme according to the polynomial function.
2. The response surface method-based lightweight design method for offshore structure pipe nodes of claim 1, wherein the strength check stress ratio of all the joints is required to meet allowable stress ratio limit when determining the constraint condition, and the constraint condition further comprises geometric dimensions.
3. The response surface method-based lightweight design method for the offshore structure pipe node, as claimed in claim 1, is characterized in that when Latin hypercube sampling is adopted to generate a sample, the constraint is satisfied that the wall thickness of a main pipe is larger than that of a branch pipe, and the combination of sample points is ensured to conform to the mechanical constraint.
4. The response surface method-based offshore structure pipe node lightweight design method according to claim 1, wherein for each sample point combination, structural analysis is performed by using a numerical simulation method, firstly, a platform integral model is established to extract axial force, shearing force and bending moment of an adjacent section of a target node, then, a solid sub-model is established, internal force data is applied and analyzed as boundary load according to the rule of node load along global coordinates and rod load along local coordinates, and finally, an accurate stress ratio is obtained.
5. The response surface method-based lightweight design method for the offshore structure pipe node of claim 1, wherein the fitting results in a polynomial function as follows: ; Wherein, the Is a structural response value predicted by the model; And Is a design variable; is the undetermined coefficient obtained by regression analysis.
6. The response surface method-based lightweight design method for offshore structure pipe nodes according to claim 1, wherein the solution is performed by adopting a sequential quadratic programming algorithm according to a polynomial function, an objective function and constraint conditions, so as to obtain a design variable combination which minimizes the total weight of the structure and simultaneously satisfies all stress ratios and other constraint conditions.
7. Offshore structure pipe node lightweight design system based on response surface method, characterized by comprising: the objective function establishing module is configured to establish a parameterized three-dimensional entity model of the objective pipe node, establish an objective function by taking the minimum total weight of the structural pipe node as a target and taking the limit strength stress ratio not larger than a preset allowable value as a constraint condition; The sample point generation module is configured to generate a series of test sample points by using Latin hypercube sampling according to the three-dimensional entity model and the objective function; the response value extraction module is configured to extract a structural response value corresponding to each sample point; the polynomial function building module is configured to obtain a polynomial function by fitting by adopting a response surface method according to the structural response value; and the design module is configured to obtain a lightweight design scheme according to the polynomial function.
8. A computer-readable storage medium, on which a computer program is stored, characterized in that the program, when executed by a processor, realizes the steps of the response surface method-based lightweight design method for an offshore structure pipe node according to any one of claims 1 to 6.
9. An electronic device comprising a memory, a processor and a computer program stored on the memory and capable of running on the processor, characterized in that the processor implements the steps of the response surface method based lightweight design method for offshore structure pipe nodes according to any one of claims 1-6 when executing the program.
10. A computer program product, characterized in that it comprises a computer program which, when executed by a processor, implements the steps of the response surface method based lightweight design method for offshore structure tube nodes according to any one of claims 1-6.

Description

Offshore structure pipe node lightweight design method and system based on response surface method Technical Field The invention belongs to the technical field of offshore converter station construction design, and particularly relates to a lightweight design method and system for offshore structure pipe nodes based on a response surface method. Background The complex pipe node of the offshore structure is a key force transfer unit for connecting each rod piece, and a plurality of pipe fittings with different diameters and different directions are spatially intersected in the same area. The intersecting lines approach or even intersect each other at the main pipe surface, resulting in dense and staggered welds, forming highly complex space curves, resulting in complex multiaxial stress states and multiple high stress regions. For complex pipe joints connecting upright posts with a plurality of diagonal braces and cross beams, designers often adopt conservative strategies, such as increasing the wall thickness of a member, so as to ensure that the joint has sufficient safety margin. However, this overly conservative design, while ensuring safety, results in a significant amount of strength redundancy at the nodes, and for large offshore platforms, the total weight of the steel structure of the upper assembly may be tens of thousands of tons, with any local overweight structure accumulating a significant economic burden. Disclosure of Invention In order to solve the problems, the invention provides a lightweight design method and a lightweight design system for offshore structure pipe nodes based on a response surface method, the invention is based on a sampled high-precision response surface model, can effectively fit a stress ratio response surface in a high-dimensional design space, and under the premise of meeting safety specifications, the complex pipe node is subjected to collaborative optimization on a plurality of key design parameters of the complex pipe node, so that constraint conditions of different inclined struts are met, structural redundancy can be accurately released, significant weight reduction is realized on the basis of not sacrificing safety, and the contradiction of safety, economy and high efficiency in the current design is solved. In order to achieve the above object, the present invention is realized by the following technical scheme: in a first aspect, the present invention provides a lightweight design method for an offshore structure pipe node based on a response surface method, including: Establishing a target function by taking the minimum total weight of the structural pipe nodes as a target and taking the limit strength stress ratio not larger than a preset allowable value as a constraint condition; According to the three-dimensional entity model and the objective function, latin hypercube sampling is adopted to generate a series of test sample points; extracting a structural response value corresponding to each sample point; fitting by adopting a response surface method according to the structural response value to obtain a polynomial function; And obtaining a lightweight design scheme according to the polynomial function. Furthermore, when the constraint condition is determined, the strength check stress ratio of all the connecting weld joints is required to meet the allowable stress ratio limit value, and the constraint condition also comprises the geometric dimension. Furthermore, when Latin hypercube sampling is adopted to generate a sample, the constraint meets the condition that the wall thickness of a main pipe is larger than that of a branch pipe, and the combination of sample points is ensured to accord with the mechanical constraint. Further, for each sample point combination, a numerical simulation method is utilized to carry out structural analysis, firstly, a platform integral model is established to extract axial force, shearing force and bending moment of the adjacent section of the target node, then, a solid sub-model is established, internal force data is applied and analyzed as boundary load according to the rule of node load along global coordinates and rod load along local coordinates, and finally, the accurate stress ratio is obtained. Further, the fitting obtains a polynomial function as follows: ; Wherein, the Is a structural response value predicted by the model; And Is a design variable; is the undetermined coefficient obtained by regression analysis. Further, according to the polynomial function, the objective function and the constraint condition, a sequence quadratic programming algorithm is adopted for solving, so that the total weight of the structure is minimum, and meanwhile, the design variable combination meeting all stress ratios and other constraint conditions is obtained. In a second aspect, the present invention further provides a lightweight design system for offshore structure pipe nodes based on a response surface method, including: