A numerical and experimental study of the indentation mechanics of plasticine

This paper describes an experimental and analytical study of contact compliance data for deriving material properties of the model elastoviscoplastic material, plasticine, from spherical and conical indentation measurements. An analytical model is employed to determine the material characteristics such as elastic modulus and yield stress from the experimental data. It is based on the Box-Cox transformation for minimizing the influence of the error inherent in compliance methods. The material characteristics deduced for plasticine are shown to be consistent with the values reported for compression tests of this material. Moreover, for the elastic modulus, yield stress, plastic flow consistency, plastic flow index and load-depth relationship, a close correlation was obtained between a finite element simulation of the indentation process and the experimental data.