Prediction of stress-strain relation using cone indentation: effect of friction

Atkins and Tabor’s approach (J. Mech. Phys. Solids 1965; 13:149) for predicting uniaxial stress– strain relation of metals from cone indentation tests has been studied using numerical (finite element) simulation of cone indentation. Two indentation parameters, namely representative strain and constraint factor, which are central to the prediction approach, have been estimated using the simulation for cone indenters of different apical angles. The effect of specimen–indenter interface friction on these parameters has been characterized. It is shown that uncertainty in our knowledge of this friction condition has an important bearing on the prediction of the stress–strain curve. However, a good estimate of the stress–strain curve can be obtained by making reasonable assumptions about the nature of the friction at the specimen–indenter interface. The simulation results are found to agree well with those reported in the experimental study of Atkins and Tabor, when a coefficient of friction value typical for the specimen–indenter interface is used