Numerical Simulation Of The Structural Strength Of Large-scale Net Cages Under The Action Of Waves And Current

In the shrinking of the fishery resources,and human is under the situation of increasing demand for seafood,commercial Marine fish farming is becoming more and more common.Offshore aquaculture is restricted by the environment of aquaculture,and deep-sea cage aquaculture has become an inevitable strategic choice for the further development of China's fisheries.Under the action of different waves and ocean currents and other Marine engineering environmental loads,the displacement,anchoring force and structural stress of the large cage,and when the cage structure occurs after the sea biological attachment,the cage will be subjected to increased load,it will endanger the safety of the cage structure.This paper firstly studies the hydrodynamic response and structural internal forces of large-scale deep-sea cages under the action of waves and currents.A numerical model of single water surface grid anchored cage is established,and the model is used as the research object for dynamic response analysis,and numerical simulation work is carried out based on related theories.Secondly,the monomer water grid anchorage area in different hydrodynamic analysis under the action of wave and current,calculate the overall deformation of the cages?the mooring lines tension,the movement and effective stress of the floating collars,mainly from the waves?currents?direction and adhesion of fouling on fish cages hydrodynamic characteristic and the structure parameter sensitivity analysis.In addition,this paper also studies the allowable extreme sea conditions of single surface grid anchoring cage under the condition of uniform adhesion of Marine organisms.The results show that the sea current velocity and the thickness of marine organisms have a great influence on the deformation?movement and force of the cage.Under different wave conditions,the maximum stress value of the floating collar appears at the back flow surface,and the type of waveform has little effect on the stress of the floating collars and the effective tension of the mooring lines.Compared with waves,ocean currents are more likely to cause deformation of cages.The force of the cage floating frame and the effective tension of the mooring lines at the wave front surface are greater than those at other positions,and the shear flow has a greater impact on the cage than the uniform flow.The effective tension of the mooring lines laid along the directions of the incoming flow is the largest,and the directions of the incoming flow has a greater influence on the displacement and stress of the floating collar.The floating collar is more susceptible to the direction of the incoming flow under irregular waves than regular waves.The attachment of sea creatures can seriously affect the force of the cage floating frame,and the impact of ocean currents on the floating frame is significantly greater than that of waves.Through the above analysis,the influence law of factors such as waves,currents and marine organisms attachment on the hydrodynamic characteristics and structural strength of the cage is obtained,which has important reference significance for the analysis of the cause of the cage damage and the design of the cage.