Statistical valuation of vibrations at the rock drilling

Abstract

The paper describes a measuring device providing a monitoring of forced vibrations arising at the rock cutting by impregnated diamond drilling tools at quasi-constant revolutions and thrust levels. The forced vibrations were measured by a capacity acceleration transducer. The vibration acceleration signal was evaluated in the time domain using the MS Excel software. The position characteristics, such as the mean value of the vibration acceleration, median; and the variability characteristics: variance, standard deviation, skewness and kurtosis. The probability density function and the distribution density were not analyzed in this stage of evaluation.The mean value of vibration acceleration depends probably on the grain size of drilled rocks. The histogram shape and the cumulative distribution function are affected by the grain size of drilled rock, as well. This fact has to be verified by further experiments. The statistical evaluation of mean values at various revolutions, rock types and drilling tools will be provided in further stages of research, together with the evaluation of vibrations in the frequency domain.

Keywords

• vibration acceleration
• mean value
• variance
• standard deviation
• skewness