Circular rings are used in various engineering structures because of their nonlinear properties. The use of large assemblies of steel rings in flexible ring nets is widespread in recent technologies of protection structures and their design requires a nonlinear and computationally efficient mechanical modeling. This paper presents an innovative discrete model of steel rings for application in flexible protection structures. The model aims at providing an effective mechanical response of the net at both the local ring scale and the global net scale. Two different uniaxial tension configurations are defined as reference loading cases and the nonlinear analytical response of the ring model to these loading cases is established. A multicriteria numerical method based on the Levenberg-Marquardt algorithm is developed to calibrate the model parameters from experimental data. An experimental campaign on steel wire spliced rings of different dimensions is conducted and permits the calibration and validation of the model.