Oscillations of dynamical systems applied in drilling : analytical and numerical methods

摘要: Kiseleva, Maria Oscillations of Dynamical SystemsApplied in Drilling: Analytical andNumerical Methods Jyvaskyla: University Jyvaskyla, 2013, 68 p.(+included articles) (Jyvaskyla Studies Computing ISSN 1456-5390; 181) ISBN 978-951-39-5518-2 (nid.) 978-951-39-5519-9 (PDF) Finnish summary Diss. This work is devoted to the study electromechanical models inductionmotorpowered drilling systems. a current issue, as equipment failures cause significant time and expenditure losses for companies. Although there are many papers investigation these systems, still occur frequently industry. In this study, we continue investigations begun by researchers from Eindhoven Technology, who introduced an experimental model system. The consists two discs connected each other steel string that experiences purely torsional deformation. upper disc driving part. lower disc, representing bottom end drill-string, friction torque caused mainly interaction with shale. key idea present distinguishes it previous was introduction more complex equations part, particular, considerations induction motor. Towards end, new mathematical considered. first simplified one, its prototype being electric hand drill. case assumed drill absolutely rigid acting on part drill-string has asymmetric characteristics Coulomb type. qualitative analysis made possible obtain parameters permissible loads (i.e., values torque) system remained operational mode after shale’s type changes. Using computer modeling, sudden load appearance also performed. second focuses deformation during operation. For characteristic, local provided. author carried out modeling created researches at Eindhoven. model, found interesting effect represented hidden stick-slip oscillations. results have been published 11 papers.