Statistical analysis of the lifetime of diamond impregnated tools for core drilling of concrete.

Malevich, N.1, a; Müller, C.1, b; Kansteiner, M.2, c; Biermann, D.2, d; Ferreira, M.3, e; Tillmann, W.3, f

1)
Chair of Statistics with Applications in the Field of Engineering Sciences, Faculty of Statistics, TU Dortmund, D-44221 Dortmund, Germany
2)
Institute of Machining Technology, TU Dortmund University, Baroper Str. 303, D-44227 Dortmund, Germany
3)
Institute of Materials Engineering LWT, TU Dortmund, Leonhard-Euler-Str. 2, D-44227 Dortmund, Germany

a) nadja.malevich@tu-dortmund.de; b) cmueller@statistik.tu-dortmund.de; c) michael.kansteiner@tu-dortmund.de; d) dirk.biermann@tu-dortmund.de; e) manuel.ferreira@udo.edu; f) wolfgang.tillmann@udo.edu

Abstract

The lifetime of diamond-impregnated tools for core drilling of concrete is studied via the lifetimes of the single diamonds on the tool. Thereby, the number of visible and active diamonds on the tool surface is determined by microscopical inspections of the tool at given points in time. This leads to interval-censored lifetime data if only the diamonds visible at the beginning are considered. If also the lifetimes of diamonds appearing during the drilling process are included, then the lifetimes are doubly interval-censored. We use a well-known maximum likelihood method to analyze the interval-censored data and derive a new extension of it for the analysis of the doubly interval-censored data. The methods are applied to three series of experiments which differ in the size of the diamonds and the type of concrete. It turns out that the lifetimes of small diamonds used for drilling into conventional concrete are much shorter than the lifetimes when using large diamonds or highstrength concrete.

Publication

Applications in Statistical Computing - From Music Data Analysis to Industrial Quality Improvement, Herausgeber: K. Ickstadt, H. Trautmann, G. Szepannek, N. Bauer, K. Lübke, M. Vichi ; Springer Verlag, (2019), pp. 233-249