Modeling of Underwater Flexible Structures and Its Application to the Fishing Gear System Simulation

This paper describes a physically based model for underwater flexible systems and presents its simulation results. In this study, a flexible structure is divided into a finite number of elements and those elements are connected with flexible lines. The elements of a structure can be modeled using the mass-spring model. The model is described as a nonlinear and stiff equation by considering the elasticity of the lines and external forces. The Newmark β method is used for the numerical integration of the system. It is found that this method offers low computational times and a stable solution. Also introduced is an algorithm to design various flexible systems using computer graphics, an automatic model creating system from the designed plan and a three-dimensional graphics tool that can show the calculated results. Application examples in design and simulation for the commercial fishing gears are presented.