A viscoelastoplastic constitutive model of semi-crystalline polymers under dynamic compressive loading: Application to PE and PA66

Abstract

Two semi-crystalline polymers: polyethylene and polyamide 66 are selected for experiments over a wide range of strain rates (10⁻²–1 s⁻¹ and 1000–4000 s⁻¹) at indoor temperature. The Young modulus and yield stress of these two materials show a great strain-rate sensitivity, implying that the semi-crystalline polymers possess obviously viscous properties. Based on the mechanical response of the materials, a corporative viscoelastoplastic constitutive model is developed to describe the dynamic response of semi-crystalline polymers. In the elastic region, a modified Kelvin model is employed to represent the viscoelastic behavior. In the post-yield regime, combining the modified Eyring theory and the strain hardening model, a corporative model is built to characterize the viscoelastic and strain hardening properties. Comparing to the experimental results for compression at high strain rates, it shows that the constitutive model accurately describes the mechanical dynamic response of semi-crystalline polymers.

Keywords:

• Constitutive model
• dynamic loading
• strain rate
• viscoelastoplastic properties
• semi-crystalline polymers

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The author(s) disclose the receipt of the following financial support for the research, authorship, and/or publication of this article: The project was supported by the National Natural Science Foundation of China (Grant No: 11472008, 11772160, 11202206), and the Natural Science Foundation of Jiangsu province, China (Grant No: BK20170819).