Prediction of viscoplastic properties of polymeric materials using sharp indentation

• Published in: Computational materials science 2015-12, Vol.110, p.321-330
• Main Authors: Inoue, Noriyuki, Yonezu, Akio, Watanabe, Yousuke, Okamura, Takeo, Yoneda, Kouji, Xu, Baoxing
• Format: Article
• Language: English
• Subjects: Algorithms; Computer simulation; Dimensionless analysis; Finite element method; Indentation; Mathematical analysis; Mathematical models; Polymer materials; Reverse analysis; Strain rate; Strain rate effect; Viscoplastic property
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2015.08.033

[Display omitted] •A new reverse algorithm is developed to probe viscoplastic properties from indentation.•Time-dependent material properties are captured through indentation loading rate with indenter geometric shapes.•A dimensionless function consisting of three viscoplastic parameters is built.•The robustness of the proposed method is verified by comprehensive numerical and experimental investigations. The present study proposes a new indentation method to predict the viscoplastic properties of polymeric materials utilizing three different indentation experiments. Numerical experiments with finite element method (FEM) are first carried out to simulate response of materials with various elastic and viscoplastic properties. The strain rate is featured by a loading rate of indentation, and the hardening rate can be captured through variations of the indenter shape. Next, a parametric FEM study is conducted to build the relationship between indentation load-depth curves and material parameters. Dimensionless analysis is employed to represent the relationship with simple formulae, through which, a reverse algorithm is proposed to extract the viscoplastic properties. Finally, both numerical and experimental investigations are performed to verify the proposed method.