CN-122021450-A - Intensity evaluation method for deep-open-sea multi-scale plate girder coupling truss cultivation net cage

CN122021450ACN 122021450 ACN122021450 ACN 122021450ACN-122021450-A

Abstract

The invention discloses a strength evaluation method of a deep-open sea multi-scale plate girder coupling truss cultivation net cage, which comprises the steps of calculating wave loads of a hydrodynamic model generated in step S2 under marine environment working condition parameters set in step S3 through step S4, fully considering wave force differences acting on a large-scale ballast tank and a small-scale truss structure, mapping the calculated panel wave force and truss wave force onto a structural unit model generated in step S1 through step S5 for coupling so as to establish load mapping between the hydrodynamic model and the structural unit model, and rapidly and accurately evaluating structural strength information of the multi-scale net cage with a variable-scale complex structure comprising the large-scale ballast tank and the small-scale truss structure under the wave condition through step S6, providing data support for design, optimization and safety evaluation of deep-open sea cultivation facility equipment, saving a large amount of manpower, material resources and financial resources, and having practical engineering significance.

Inventors

LIU HANGFEI
Chen Xinding
ZHANG XIAOFENG
HUANG XIAOHUA
PANG GUOLIANG
LI GEN
YUAN TAIPING
HU YU
TAO QIYOU
DING MU

Assignees

中国水产科学研究院南海水产研究所

Dates

Publication Date: 20260512
Application Date: 20260211

Claims (6)

1. The strength evaluation method of the deep-open-sea multi-scale plate girder coupling truss cultivation net cage is suitable for a multi-scale net cage formed by connecting a plurality of large-scale ballast tanks (1) and small-scale truss structures (2); Characterized by comprising the following steps: S1, generating a panel unit model, a truss unit model and a structure unit model of the multi-scale net cage, wherein the panel unit structure, the truss unit structure of the small-scale truss structure (2) and the whole unit structure of the multi-scale net cage can be respectively represented by the panel unit model, the truss unit model and the structure unit model of the multi-scale net cage, and the whole unit structure comprises the panel unit structure, the truss unit structure and the internal reinforcing rib unit structure of the large-scale ballast tank (1); S2, generating the panel unit model and the truss unit model into hydrodynamic models, and setting the volume of water in a ballast tank of the panel unit model so that the hydrodynamic models reach a target draft; s3, setting marine environment working condition parameters of the position of the multi-scale net cage; S4, calculating panel wave force acting on the panel unit (1-1A) by adopting a radiation diffraction method based on the hydrodynamic model and marine environment working condition parameters, and calculating truss wave force acting on the truss unit (2A) by using a Morisen equation; s5, mapping the panel wave force and the truss wave force to a panel unit (1-1A) and a truss unit (2A) corresponding to the structural unit model respectively; And S6, adopting a quasi-static force method to carry out linear solution on the structural unit model obtained in the step S5 so as to obtain the stress, shearing force and bending moment distribution condition of the multi-scale net cage.
2. The method for evaluating the strength of the deep-open-sea multi-scale plate girder coupling truss cultivation net cage according to claim 1, wherein the step S1 specifically comprises the following steps: S1-1, establishing a geometric model of the multi-scale net cage, and realizing connection and load transfer between a small-scale truss structure (2) in the geometric model and a ballast tank panel (1-1) of a large-scale ballast tank (1) and between the ballast tank panel (1-1) and a ballast tank internal reinforcing rib (1-2) through topological sharing; s1-2, setting structural properties and material properties of the geometric model; S1-3, mesh dissection is carried out on the geometric model so as to divide a ballast tank panel (1-1), a ballast tank internal reinforcing rib (1-2) and a small-scale truss structure (2) into a plurality of panel units (1-1A), reinforcing rib units and truss units (2A), wherein the panel units (1-1A) adopt shell units, and the reinforcing rib units and the truss units (2A) adopt beam units; Step S1-4, setting boundary conditions for constraining six degrees of freedom of the geometric model; And step S1-5, generating a panel unit model, a truss unit model and a structural unit model of the multi-scale net cage based on the steps S1-1 to S1-4, wherein the panel unit model comprises all panel units (1-1A), the truss unit model comprises all truss units (2A), and the structural unit model comprises all panel units (1-1A), reinforcing rib units and truss units (2A).
3. The method for evaluating the strength of a deep-open-sea multi-scale plate girder coupling truss aquaculture net cage according to claim 1, wherein in the step S2, the buoyancy and the gravity of the hydrodynamic model are evaluated through static calculation according to the hydrodynamic model and the target draft, and the volume of the water in the ballast tank required by the hydrodynamic model to reach the target draft is calculated.
4. The method for evaluating the strength of a deep-open-sea multi-scale plate girder coupling truss cultivation net cage according to claim 1, wherein in the step S3, the marine environment working condition parameters comprise gravitational acceleration, sea water density, water depth, wave period and wave direction.
5. The method for evaluating the strength of the deep-open-sea multi-scale plate girder coupling truss cultivation net cage according to claim 1, wherein in the mapping process of the step S5, the load mapping angle between the hydrodynamic model and the structural unit model is controlled within 20 degrees.
6. The method for evaluating the strength of the deep-open-sea multi-scale plate girder coupling truss cultivation net cage according to claim 1, wherein the method for evaluating the strength is further characterized by comprising the following steps: and S7, comparing the stress, shear force and bending moment distribution conditions obtained in the step S6 with the yield strength of the structural material at the corresponding position of the multi-scale net cage so as to evaluate the structural safety of the multi-scale net cage.

Description

Intensity evaluation method for deep-open-sea multi-scale plate girder coupling truss cultivation net cage Technical Field The invention relates to structural safety assessment of a culture net cage, in particular to a strength assessment method of a deep-open-sea multi-scale plate girder coupling truss culture net cage. Background The deep-open sea multi-scale plate girder coupling truss aquaculture net cage is a multi-scale net cage formed by connecting a plurality of large-scale ballast tanks and small-scale truss structures and has a variable-scale complex structure, and for example, the multi-scale net cage shown in fig. 1 and 2 is formed by connecting four large-scale ballast tanks 1 positioned at a bow position, a small-scale truss structure 2 positioned at a middle position and two large-scale ballast tanks 1 positioned at a stern position. The large scale ballast tank 1 and the small scale truss structure 2 are of different scales in that the cross section of the individual round tubes that make up the truss structure is much smaller than the cross section of the ballast tank. In the prior art, the strength calculation method of the multi-scale net cage under the wave action mostly adopts Morisen theory to evaluate the deformation and stress of the gravity net cage, and adopts radiation diffraction theory to analyze the hydrodynamic force of a large-scale structure, which has the following defects: Firstly, calculating wave force acting on a traditional gravity net cage based on Morisen equation by adopting a centralized mass method and evaluating deformation of the net cage, so that influence of radiation diffraction wave force on structural strength of the net cage cannot be considered; secondly, calculating hydrodynamic response of the large-scale net cage by adopting potential flow theory, wherein the hydrodynamic response comprises mooring force and motion response, but the hydrodynamic response is mostly based on rigid body theory, so that deformation and stress distribution of the structure cannot be considered; Thirdly, the CFD method can evaluate the water resistance acting on the net cage and the flow field distribution near the net cage, which assumes that the net cage is a rigid body and cannot take the deformation and stress distribution of the structure into consideration. In summary, the existing strength calculation method cannot evaluate the strength of the deep open sea multi-scale plate girder coupling truss cultivation net cage formed by connecting the large-scale ballast tank 1 and the small-scale truss structure 2. The existing method is single, and cannot process the strength evaluation of the variable-scale complex structure. Disclosure of Invention The invention aims to solve the technical problem of providing a strength evaluation method for a deep-open sea multi-scale plate girder coupling truss cultivation net cage, which aims to solve the problem that the prior art cannot accurately evaluate the structural strength of the multi-scale net cage comprising a large-scale ballast tank and a small-scale truss structure under the action of waves. The technical scheme adopted by the invention is as follows: As shown in fig. 3, the strength evaluation method of the deep-open sea multi-scale plate girder coupling truss cultivation net cage is applicable to the multi-scale net cage formed by connecting a plurality of large-scale ballast tanks and small-scale truss structures; Comprising the following steps: Step S1, generating a panel unit model, a truss unit model and a structural unit model of the multi-scale net cage, wherein the panel unit structure, the truss unit structure of the small-scale truss structure and the whole unit structure of the multi-scale net cage can be respectively represented, and the whole unit structure comprises the panel unit structure, the truss unit structure and the internal reinforcing rib unit structure of the large-scale ballast tank; S2, generating the panel unit model and the truss unit model into hydrodynamic models, and setting the volume of water in a ballast tank of the panel unit model so that the hydrodynamic models reach a target draft; s3, setting marine environment working condition parameters of the position of the multi-scale net cage; s4, calculating panel wave force acting on the panel unit by adopting a radiation diffraction method based on the hydrodynamic model and marine environment working condition parameters, and calculating truss wave force acting on the truss unit by using a Morisen equation; s5, mapping the panel wave force and the truss wave force to a panel unit and a truss unit corresponding to the structural unit model respectively; And S6, carrying out linear solving on the structural unit model obtained in the step S5 by adopting a quasi-static force method so as to obtain stress, shearing force and bending moment distribution conditions including ballast tank panels, reinforcing ribs in the ballast tanks and small-