Quasistatic critical states of strings for deep drilling

We pose the problem of buckling of an elongated twisted rotating rod subjected to tension-compression and containing an internal flow of homogeneous fluid. We derive the resolving equations capable of modeling the stability of strings for deep drilling, propose a procedure for their solution, and consider typical examples. The critical values of the parameters of the system specifying its elastic equilibrium are determined and the stability loss modes of are established. __________ Translated from Problemy Prochnosti, No. 5, pp. 109–119, September–October, 2006.