Strength Analysis of Offshore Aquaculture Net Structure under Wave and Current Loads

One of the main problems of floating net cages when operating is the escape of fish caused by breaking or tearing of the net. This is due to the influence of environmental loads that have been studied by several researchers. However, the influence of fish on net strength has not been considered. The schooling of fish in the cage can make the hydrodynamic flow change downstream of the cage. The collision of fish in groups on the net can increases 10-28% of the environmental load received by the net. Besides, fish bites on the net reduce the net cross-sectional area and lead to axial stiffness reduction. So, this study focuses on the analysis of the net strength to determine the net maximum tension, deformation, and the location of each parameter by considering the influence of fish in the net cage Simulations are conducted out using finite element method software with cage models based on physical and numerical experiments from prior studies. The results show that the net could withstand operating conditions. Meanwhile, in extreme conditions, the net could only survive in the 0° loading direction. The largest deformation reached 2.5 times the diameter of the cage. The collision of fish in groups on the net showed that the tensile force increased significantly when adding stress loading factor. While the effect of fish bites showed that the tensile force significantly decreased on all threads with a reduction in cross-sectional area.