Drill string nonlinear vibrations: Experimental studies and finite-element analysis

Abstract

In the present work, nonlinear vibrations of drill strings are studied. A laboratory scale arrangement consisting of a flexible rod with rotor-stator system is used to study the system dynamics. A finite-element model has been developed to study the system dynamics. Qualitative changes in the system dynamics are examined with respect to variation in the rotation speed, with a focus on whirling and stick-slip motions. The finite-element model results are compared with experimental results. It is believed that the developed finite-element model can be important for the design analysis of drill strings as well as understanding the system dynamics.