A static analysis of the tension and configuration of submerged plane nets

Abstract

A non-linear finite element method is employed to determine the equilibrium configuration and tension distribution of a net set in a uniform current. The method models each mesh bar in the net as an infinitely flexible rope element connected at each end to other elements by a frictionless hinge. The Newton-Raphson method is used to solve the basic non-linear simultaneous equations with respect to tension in mesh bar and knot displacements. Global convergence to the correct solution from an initially estimated state is ensured using a loading iteration in addition to the common configuration iterative procedure in order to accurately model the shape-dependent characteristic of hydrodynamic forces. The method is shown to predict the shape and tension distribution of fishing nets with reasonable accuracy in the case examined in the present study.