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**A study on the determination of plastic properties of metals by instrumented indentation using two sharp indenters.**
*(English)*
Zbl 1178.74070

Summary: An earlier optimisation approach proposed by J. Luo et al. [A Study on the Determination of Mechanical Properties of a power-law Material by Its Indentation Force-Depth Curve. Philos. Mag. 86, No. 19, 2881–2905 (2006)], which is based on the assumption that the instrumented indentation force-depth response of an elastic-plastic material is a linear combination of the corresponding elastic and elastic-perfect plastic materials, is extended in this work to extract mechanical properties of a power-law material from two given experimental indentation \(P-h\) curves for conical indenters of half included angles of \(60^\circ \) and \(70.3^\circ\) . It was found that the non-uniqueness problem encountered in the single \(P-h\) curve optimisation approach is effectively removed by the two \(P-h\) curves optimisation. The appropriateness of the use of second half included angle of \(60^\circ \) is discussed. For the five representative materials Al, Ti, Fe, Ni and steel, it was found that the maximum relative prediction errors for \(E\), \(\sigma _{y}\) and \(n\) are 2%, 10.4% and 11.3%, respectively. The prediction accuracy of mechanical properties \(E\), \(\sigma _{y}\) and \(n\) is generally better than other methods reported in the literature.

### MSC:

74G75 | Inverse problems in equilibrium solid mechanics |

74C99 | Plastic materials, materials of stress-rate and internal-variable type |

74M15 | Contact in solid mechanics |

74S05 | Finite element methods applied to problems in solid mechanics |