Consideration of Tool Chamfer for Realistic Application of the Incremental Hole-Drilling Method

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Consideration of Tool Chamfer for Realistic Application of the Incremental Hole-Drilling Method

N. Simon, J. Gibmeier

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Abstract. The incremental hole-drilling method is well-established in residual stress analysis. A small blind hole is drilled incrementally and the strain relief is measured on the sample’s surface. In order to calculate residual stresses from the measured strain calibration data is necessary. Typically, the calibration data is determined numerically and is based on the assumption of an ideal cylindrical blind hole. However, widely used six-blade milling bits have rather large chamfers at the cutting edges, which result in hole geometries that clearly differ from the ideal cylindrical blind hole. Especially in the first drilling increments a significant impact on the calibration data by the real hole geometry is expected. In this work, a numerical model is set up that allows for consideration of tool chamfers. A systematic finite element study is carried out to analyze the effect on relieved strains. Calibration data is computed for the ideal blind hole as well as for the realistic hole geometry. Finally, numerical results are compared with experimental results gained by defined uniaxial loading experiments. The results clearly indicate a significant impact of the tool chamfer geometry for strain relief and stress data close to the surface. Hence, based on the results it is highly recommended to consider the real tool geometry to provide accurate stress evaluation by means of the incremental hole-drilling method in particular for the first drilling increments.

Keywords
Residual Stress Measurement, Incremental Hole-Drilling Method, Hole Geometry, FEM

Published online 12/22/2016, 6 pages
Copyright © 2016 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: N. Simon, J. Gibmeier, ‘Consideration of Tool Chamfer for Realistic Application of the Incremental Hole-Drilling Method’, Materials Research Proceedings, Vol. 2, pp 473-478, 2017

DOI: http://dx.doi.org/10.21741/9781945291173-80

The article was published as article 80 of the book Residual Stresses 2016

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

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