In this work, we propose a new four-parameter micromechanical model to describe the hyperelastic behavior of elastomeric materials. The proposed model extends and improves a previously developed three-parameter micromechanical approach. As in earlier studies, the constitutive behavior is obtained by minimizing the potential energy of a Representative Volume Element (RVE) composed of multiple macromolecular chains. Each chain segment is modeled as a linear spring with stiffness $K$, acting in both tension and compression. To account for rotational flexibility between consecutive segments, nonlinear torsional springs are introduced, whose behavior is described as the sum of two contributions:... More >