کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1560528 1513919 2014 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Large-strain viscoelastic-viscoplastic constitutive modeling of semi-crystalline polymers and model identification by deterministic/evolutionary approach
ترجمه فارسی عنوان
مدل سازی سازنده اساسی کلاسیک-ویسکوکالستیک با استفاده از پلیمرهای نیمه بلوری و شناسایی مدل با رویکرد مؤثر / تکاملی
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مکانیک محاسباتی
چکیده انگلیسی
Above the glass transition temperature, a semi-crystalline polymer can behave like an elastomer or a stiff polymer according to the crystal content. For a reliable design of such polymeric materials, it is of prime importance to dispose a unified constitutive modeling able to capture the transition from thermoplastic-like to elastomeric-like mechanical response, as the crystal content changes. This work deals with polyethylene materials containing a wide range of crystal fractions, stretched under large strains at room temperature and different strain rates. A large-strain viscoelastic-viscoplastic approach is adopted to describe the mechanical response of these polymers. In order to identify the model parameters, an analytical deterministic scheme and a practical, “engineering-like”, numerical tool, based on a genetic algorithm are developed. A common point of manipulated constitutive models is that the elementary deformation mechanisms are described by two parallel resistances; one describes the intermolecular interactions and the other deals with the molecular network stretching and orientation process. In a first approach, the semi-crystalline polymers are considered as homogeneous media; at each crystal content, the semi-crystalline polymer is thus considered as a new material and a new set of model parameters is provided. In a second approach, the semi-crystalline polymer is seen as a two-phase composite, and the effective contribution of the crystalline and amorphous phases to the overall mechanical response is integrated in the constitutive model, which allows simulating the transition from thermoplastic-like to elastomeric-like mechanical response. In this case, one set of model parameters is needed, the only variable being the crystal volume fraction. The identification results obtained using deterministic and numerical methods are discussed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Computational Materials Science - Volume 90, July 2014, Pages 241-252
نویسندگان
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