CN-122020775-A - Pile type fence structure load dynamic response model construction method

Abstract

The invention belongs to the field of marine devices, and provides a pile type fence structure load dynamic response model construction method, which comprises the steps of obtaining engineering arrangement parameters of a fence structure, constructing a wave flow field near the fence structure based on potential flow theory, and calculating the speed and acceleration of water particles; the pile and the connecting member are regarded as rigid structures, a rigid dynamic motion equation is established, the netting system is regarded as a flexible structure, a dynamic model is established by adopting a concentrated mass point method, hydrodynamic loads of the pile, the netting and the connecting member are calculated, effective tension of the thin rod member is calculated, horizontal bearing capacity of the pile foundation is calculated to simulate pile-soil interaction, and finally, a semi-implicit Euler method is adopted to carry out numerical solution on the dynamic equation, so that dynamic response results of pile bending moment, netting tension and node displacement are obtained. The invention can comprehensively reflect the multisystem coupling power response characteristic of the pile type fence structure under the wave action, and is suitable for safety evaluation and engineering design of the fence structure.

Inventors

• CHEN HONGZHOU
• MEI LILI
• GUI FUKUN
• FENG DEJUN

Assignees

• 浙江海洋大学

Dates

Publication Date

20260512

Application Date

20251224

Claims (10)

1. 1. The construction method of the pile type fence structure load dynamic response model is characterized in that the pile type fence structure comprises a pile system, a netting system and a connecting member, and comprises the following steps: Obtaining structural parameters of a pile system, a netting system and an upper connecting member according to the engineering arrangement form of the pile type fence structure; adopting potential flow theory to treat fluid near the fence as ideal fluid with no rotation, no viscosity and velocity potential, and simplifying the velocity potential problem in the flow field into a Laplacian equation with fluid boundary conditions; The pile and the connecting member are regarded as rigid structures, rigid motion equation is established by adopting rigid motion theory, Regarding the netting as a flexible structure, equivalently acting the load acting on the units on the concentrated mass points, and establishing a motion differential equation about the mass points; Calculating hydrodynamic loads of piles, netting and connecting members based on an improved Morison equation; taking piles, netting and connecting member thin rod members as line units of a hollow pipe structure, and calculating effective tension of the line units; calculating the horizontal bearing capacity of the pile foundation by adopting a p-y curve method; and solving the acceleration, the speed and the displacement of the pile and the net node under a fixed time step by adopting a semi-implicit Euler method, and updating the positions and the directions of the free body and the flexible node in a prediction-correction-iteration mode until the continuous two iteration errors meet the convergence condition to obtain the dynamic response result of pile bending moment, net tension and node displacement.
2. 2. The method for constructing a pile type fence structure load dynamic response model according to claim 1, wherein the structural parameters include: Diameter of pile, length of pile, density of pile material and elastic modulus of pile material; The wire diameter, mesh size, density and elastic modulus of the netting material; The spacing between adjacent piles, the hanging height of the netting on the piles and the arrangement mode of the connecting members.
3. 3. The method for constructing a pile-type fence structure load dynamic response model according to claim 1, wherein the laplace equation with fluid boundary conditions is: , In the formula, 、 、 、 Respectively representing a first order velocity potential, a first order incident potential, a first order radiation potential and a first order diffraction potential, 、 、 Is a spatial coordinate.
4. 4. The method for constructing a pile type fence structure load dynamic response model according to claim 1, wherein the rigid motion equation is: , In the formula, Is the inertial load of the system unit, Is the damping force of the system and, Is the rigidity load of the system, Is the cell external load, p, v and a are the cell position, velocity and acceleration vectors, respectively, and t is the simulation time.
5. 5. The method for constructing a pile type fence structure load dynamic response model according to claim 1, wherein the differential equation of motion of the mass point is: , In the formula, In order to concentrate the mass of the mass points, For the acceleration of the vehicle body, Is the drag force of the drag force and, Is the force of inertia and is the force of inertia, Is the tension of the net wires, and the net wires are stretched, And Representing the buoyancy and gravity forces experienced by the mass point, respectively.
6. 6. The method for constructing a pile-type fence structure load dynamic response model according to claim 1, wherein the improvement Morison equation is: , Wherein: representing fluid load; representing a drag coefficient; Representing fluid density; Representing the projected area of the structure along the flow velocity direction; Representing the speed of the structural unit; representing the structural unit acceleration; Indicating the water quality point speed; Indicating water particle acceleration; Representing the volume of drainage; Representing an additional quality factor.
7. 7. The method for constructing the pile type fence structure load dynamic response model according to claim 6, wherein the drag coefficient takes a value of 1.4.
8. 8. The construction method of pile type fence structure load dynamic response model according to claim 6, characterized in that the additional mass coefficient takes a value of 2.0.
9. 9. The method for constructing a pile type fence structure load dynamic response model according to claim 1, wherein the effective tension of the wire unit is calculated by the following method: , In the formula, Is the effective tension of the wire unit, Is the tension of the outer wall of the pipeline, Is the internal pressure of the fluid in the fluid, Is the external pressure of the air, which is, Is the internal cross-sectional area of the pipeline, Is the external cross-sectional area.
10. 10. The construction method of pile type fence structure load dynamic response model according to claim 9, characterized in that the outer wall tension force The formula of (2) is as follows: , In the formula, Is the modulus of elasticity of the thread unit, Is the effective cross-sectional area of the device, For the axial strain of the unit cell, Is the poisson's ratio, 、 The inner and outer cross-sectional areas of the pipeline units, Is the damping coefficient of the material, and, Is the initial length of the line element, Is the current length of the line element, Is the iteration time.

Description

Pile type fence structure load dynamic response model construction method Technical Field The invention belongs to the field of marine devices, and particularly relates to a pile type fence structure load dynamic response model construction method. Background Along with the continuous expansion of the offshore fishery cultivation scale, rail cultivation is taken as an important marine cultivation mode and is widely applied to the large-scale cultivation process of aquatic economic animals such as fishes and the like. The fence culture generally forms a relatively closed culture water body in an offshore water area through engineering facilities such as piles, netting, ropes, connecting members and the like, so that effective enclosure and management of a culture object are realized. According to different structural forms, the existing fence culturing facilities mainly can be divided into two types of floating rope type fences and pile type fences. The floating rope type fence usually adopts a structural form of combining a flexible floating body and a net, is flexible to lay, has relatively low requirements on sea conditions, is easy to deform greatly and even is damaged in structure under strong wind and wave conditions due to low rigidity of the whole structure, and is difficult to meet the requirements on safe operation under high-risk sea conditions. In contrast, the pile type fence provides higher overall rigidity and bending resistance for the fence structure by anchoring the pile in the seabed, has obvious advantages in resisting ocean power actions such as waves, currents and the like, and is widely applied to cultivation projects with larger investment scale and higher structural safety requirements. However, as a relatively emerging ocean engineering structure form, pile type fences still lack systematic and mature technical support in engineering design theory. The prior researches focus on hydrodynamic characteristic analysis of fence structures or components thereof under the action of waves and water currents, such as researching tension distribution and deformation characteristics of a netting system by utilizing a centralized mass point method, or analyzing the influence of factors such as wave parameters, netting size, pile row number and the like on local stress by numerical simulation and test means. Such studies reveal to some extent the stressed characteristics of the rail structure, but mostly stay at the analytical level of a single structural component or a single physical process, and no complete load dynamic response model facing the engineering design needs has been formed. In the prior art, for hydrodynamic analysis of pile-type fence structures, static or quasi-static methods are mostly adopted, or the adverse effect of structural motion on hydrodynamic load is ignored in a numerical model. Under the condition of obvious following of strong nonlinear wave working conditions or structures, the method is easy to cause load estimation deviation, and is difficult to provide reliable basis for safety evaluation and structure optimization of fence structures. Especially when different pile arrangement forms, different surmounting design schemes and different foundation conditions are involved, the prior art is lack of a unified modeling method capable of comprehensively considering wave flow fields, structural power response and pile-soil interaction. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a pile type fence structure load power response model construction method, wherein the pile type fence structure comprises a pile system, a netting system and a connecting member, and the method comprises the following steps: Obtaining structural parameters of a pile system, a netting system and an upper connecting member according to the engineering arrangement form of the pile type fence structure; adopting potential flow theory to treat fluid near the fence as ideal fluid with no rotation, no viscosity and velocity potential, and simplifying the velocity potential problem in the flow field into a Laplacian equation with fluid boundary conditions; The pile and the connecting member are regarded as rigid structures, rigid motion equation is established by adopting rigid motion theory, Regarding the netting as a flexible structure, equivalently acting the load acting on the units on the concentrated mass points, and establishing a motion differential equation about the mass points; Calculating hydrodynamic loads of piles, netting and connecting members based on an improved Morison equation; taking piles, netting and connecting member thin rod members as line units of a hollow pipe structure, and calculating effective tension of the line units; calculating the horizontal bearing capacity of the pile foundation by adopting a p-y curve method; and solving the acceleration, the speed and the displacement of the pile and the net node under a fixed