## Abstract

Several procedures have previously been advanced for extracting constitutive relations from the force-displacement curves obtained from indentation. This work addresses the specific problem of determining the elastic modulus E, yield stress Y, and hardening exponent n, which define the isotropic strain-hardening model from a single force-displacement curve with a sharp conical tip. The sensitivity of the inversion process was tested through a series of finite element calculations using ABAQUS. Different magnitudes of normally distributed noise were superimposed on a calculated force-displacement curve to simulate hypothetical data sets for specific values of E, Y, and n. The sensitivity of the parameter confidence intervals to noise was determined using the Χ^{2}-curvature matrix, statistical Monte Carlo simulations, and a conjugate gradient algorithm that explicitly searches the global parameter space. All three approaches demonstrate that 1% noise levels preclude the accurate determination of the strain-hardening parameters based on a single force-displacement curve.

Original language | English |
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Pages (from-to) | 827-832 |

Number of pages | 6 |

Journal | Journal of Materials Research |

Volume | 18 |

Issue number | 4 |

DOIs | |

State | Published - Apr 2003 |

## ASJC Scopus subject areas

- General Materials Science
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering