@inproceedings{d4ba2dd772574359b1e4e822ac68d387,
title = "Vertical vibrations and detachments of drill bits in rotary drilling",
abstract = "This study deals with vertical vibrations (chatter) in the deep rotary drilling. The vertical vibrations play negative role in this type of drilling, since they cause detachment of a drill bit from the rock and subsequent impacts (bit-bounce), thus decreasing the cutting efficiency and producing additional wear on the drill bit. The main mechanism of this chatter is a bilinear stiffness of the drilling system due to low stiffness of the long drill string and comparatively high stiffness of the rock. In this study, we assume the rock as infinitely rigid and model the system as an impact oscillator. This oscillator is excited by the vertical momentum created by the rock asperities encountered by the rotating drill bit in the process of drilling. The oscillations are governed by the combined mass of the drill bit, the collar, the mud trapped there as well as the rotational speed, the viscosity of the mud and the fraction of the energy consumed in rock fragmentation. We demonstrate that the high rotational speeds lead to the vertical chatter and discuss ways to suppress these oscillations.",
keywords = "Coefficient of restitution, Damping, Impact oscillator, Impact velocity, Mud viscosity",
author = "Dyskin, {Arcady V.} and Elena Pasternak and Igor Shufrin",
year = "2012",
month = jan,
day = "1",
language = "English",
isbn = "9781922107619",
series = "Advances in Applied Mechanics Research, Conference Proceedings - 7th Australasian Congress on Applied Mechanics, ACAM 2012",
publisher = "National Committee on Applied Mechanics",
pages = "1080--1090",
booktitle = "Advances in Applied Mechanics Research, Conference Proceedings - 7th Australasian Congress on Applied Mechanics, ACAM 2012",
note = "7th Australasian Congress on Applied Mechanics, ACAM 2012 ; Conference date: 09-12-2012 Through 12-12-2012",
}