Modeling the effect of temperature and degree of crystallinity on the mechanical response of Polyamide 6
Modeling the effect of temperature and degree of crystallinity on the mechanical response of Polyamide 6
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DOI：
10.1016/j.mechmat.2020.103476
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发表时间：
2020-09-01
影响因子：
3.9
通讯作者：
Simon, J-W
中科院分区：
文献类型：
--
作者：
Felder, S.;Vu, N. A.;Simon, J-W
在目前的工作中，进行了广泛的实验研究，以调查两者的影响，在很宽的温度范围内的应用的热条件和制造工艺诱导的结晶度的半结晶聚合物的机械响应。为此，大应变拉伸实验与不同的加载程序（即单调，循环，松弛试验）进行聚酰胺6不同的加载速率。实验数据库为有效材料性能对上述因素的复杂依赖关系提供了新的见解，并作为连续体力学本构框架发展的基础。现象学、等温模型以合理通用、热力学一致的方式开发，以预测应变率，温度和结晶度依赖的半结晶聚合物的大变形响应。本文提出了一种非线性粘弹性、弹塑性耦合理论，该理论结合了非线性各向同性和运动硬化，能够描述复杂的材料行为（如循环加载-卸载和非线性应力松弛后的应变恢复和滞后回线）。提出了一种交错表征方法，从实验数据中识别一组材料参数。最后，验证研究证明了新的本构框架的巨大能力，准确地预测温度和结晶度对材料响应的显着影响。
In the current work, an extensive experimental study is performed, to investigate the influence of both, the applied thermal conditions over a wide range of temperatures and the manufacturing process induced degree of crystallinity on the mechanical response of semi-crystalline polymers. To this end, large-strain tensile experiments with different loading procedures (i.e. monotonic, cyclic, and relaxation tests) are conducted on Polyamide 6 for different loading rates. The experimental data base provides new insights into the complex dependencies of the effective material properties on the aforementioned factors and serves as the foundation for the development of a continuum mechanical constitutive framework.The phenomenological, isothermal model is developed in a reasonably general, thermodynamically consistent manner, to predict the strain rate, temperature and degree of crystallinity dependent large-deformation response of semi-crystalline polymers. A coupled nonlinear visco-elastic, elasto-plastic theory, incorporating nonlinear isotropic and kinematic hardening, is proposed to capture the complex material behavior (e.g. strain recovery and hysteresis loop after cyclic loading-unloading and nonlinear stress relaxation). A staggered characterization method is proposed, to identify a set of material parameters from the experimental data. Finally, validation studies demonstrate the great capabilities of the novel constitutive framework, to accurately predict the significant influence of the temperature and degree of crystallinity on the material response.