Finite element model for the assessment of the mesh resistance to opening of fishing nets

The evaluation of the mesh resistance to opening of fishing nets is an important issue in assessing the selectivity of trawls by numerical methods. Sala et al. (2007) proposed a method using a relatively expensive experimental device ensuring the 2D deformation of net sample. De la Prada and Gonzales (2015) proposed a simple uni-axial experimental set-up, which stretches a sample in the transverse direction of the meshes while leaving free its deformation in the normal direction. Both authors (Sala and De la Prada) assumed that the deformation is uniform in the sample. The present study aims at developing a finite element model taking into account the mesh resistance to opening of nets, allowing the simulation of non-uniform deformation. Mechanical experimental tests were performed on a range of fishing nets commonly used in trawl codends, with varied dimensions of the sample and loading. The proposed model is in good agreement with these experimental results, and it captures the heterogeneous deformation of the netting samples. Consequently, a procedure for the assessment of the mesh resistance to opening using this model and a simple non-expensive experimental setup are proposed.