Determination of the elastic and plastic properties of materials through instrumented indentation with reduced sensitivity

By considering the complete loading and unloading response characteristics of multiple sharp indentations with differing indenter apex angles, a new approach has been developed to extract the elastic and plastic properties of materials. Considerable reduction in the sensitivity characteristics of all the indentation parameters invoked in the reverse analysis for the identification of the elastic and plastic properties of the indented material is realized. The reduction in sensitivity obtained using the present approach is attributed to an optimization process that identifies the material properties that best describe all the available information from multiple indentations. A comprehensive comparison of several multiple indentation methods for a large number of material combinations illustrates that the triple indentation method that does not utilize representative stresses and the quadruple indentation method that invokes representative stresses provide the least sensitivity in the determination of elastic and plastic properties.