Modeling Finite Deformation Behavior of Semicrystalline Polymers under Uniaxial Loading—Unloading

The aim of this work is to investigate the finite deformation behavior of polymeric materials under monotonic loading—unloading. The strain rate sensitivity behaviors of polymeric materials were modeled using viscoplasticity theory based on an overstress (VBO) model. The modeling capability of the VBO model was improved to describe the nonlinear stress—strain behavior of the fully inelastic flow region in loading at small strain level. In this model, the tangent modulus (Et) is taken nonlinearly to simulate this polymeric material behavior. The numerical results were compared to the experimental data in the literature. These results were in good agreement with the experimental data.