EVALUATION OF UNCERTAINTY OF CONTACT POINT AND CONTACT DEPTH BY USING NON-LINEAR FITTING

Koichiro Hattori, Yutaka Seino

Abstract

The one of difficulties is how to evaluate the origin of depth from force-indenter displacement curve in instrumented indentation test (IIT). One of determination technique it is that using the fitting using some model function. How to evaluate the uncertainty of the fitted coefficients is another problem in this case. We have been developing the uncertainty evaluation software and the uncertainty of fitting of power-law is evaluated by using the final Jacobian matrix of iteration process. In this paper, we explained the uncertainty calculation for the non-linear function. We applied it to the contact point estimation for force-depth curve obtained by the fused silica as a typical example. We also discussed the effect of model function and data length, which is obtained by the developed software.

Keywords

instrumented indentation test, uncertainty of fitting

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IMEKO-TC5-2010-028.pdf

DOI

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IMEKO TC

TC5 - Hardness Measurement

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