Observations are reported on isotactic poly(propylene) (iPP) in a series of tensile loading‐unloading tests with a constant strain rate at room temperature. A constitutive model is developed for the elastoplastic behavior of a semicrystalline polymer at isothermal uniaxial deformations with small strains. The stress‐strain relations are determined by 5 adjustable parameters which are found by fitting the experimental data.
The stress σ (MPa) versus strain ε in a tensile loading‐unloading test with the maximum strain εmax = 0.09. Circles: experimental data. Solid line: results of numerical simulation.
