Numerical Analysis of Mechanical Behavior of Semi-Crystalline Polymers Based on Continuum Damage Mechanics

In the current study, semi-crystalline polymers and their properties are introduced, and then a mechanical model is precisely presented in order to predict the behavior of these materials. In this model, a material point of the semi-crystalline polymer is considered as an aggregate of inclusions of two phases, namely, the crystalline and the amorphous phase, with the interface plane of these two phases. Constitutive equations of each phase are demonstrated. A numerical algorithm is presented for solving the constitutive equations of each phase, in stages. Moreover, the general behavior of the material is determined in terms of each phase behavior using volume averaging. Because of the availability of the material parameters for polyethylene, this material has been taken into account. Obtained numerical results are reported and compared to that of previous models. After supporting the validity of the presented model, the effect of some material parameters including crystalline phase damage rate, release parameter, amorphous phase damage rate, saturation damage, rubber shear modulus, and amorphous phase strength on polyethylene behavior has been discussed in details.