Dynamics of a rotating column slender subject to friction in two distinct regions
Adriano Domeny dos Santos1; Hans Ingo Weber1
1 Pontifícia Universidade Católica do Rio de Janeiro
doi:10.20906/CPS/COB-2015-1871
Resumo
In order to better understand the dynamic behavior of a drill string subjected to various electrical and mechanical strains, a series of numerical experiments were conducted based on the theoretical model bench representative of a drilling system, comprising of a DC motor coupled to a double torsional pendulum. The pendulum, in turn, is comprised by a slender cylindrical rod and attached to the rod, one at the opposite end to the motor, and the other at an intermediate point of the rod. Coupled to the inertia discs are two disc brake systems, which two massive discs experimentally simulate the bit-rock interaction and a second relevant source of friction. The numerical experiments were performed varying the friction intensities in the disc brake systems, and observing the dynamic response of the coupled system from the variations in time of various measurable quantities in the engine, among them the reaction torque, and the rotational speed of its shaft. The motion equations were derived starting from the calculation of the Lagrangian of the electromechanical system under study, and using the generalized forces associated with the dissipation sources, which are mechanical and electrical in nature.
Palavras-chave: drilling system; concentrated parameters; optimization