The stability of shafts under the action of periodic axial loads

Abstract

The paper presents the investigation results of the harmonic periodic axial loads’ influence on the stability of shaft. Such loads can be appeared during the running of the vessel passing the turbulence zones from the side of the propeller to the shafting. In shafting, the influence of oscillatory motion performed in adjacent part, which is transmitted through the coupling due to longitudinal movements, can be periodic, too. Therefore, the question of the stability of such shafts during rotation is relevant. In this way, the task of such drill-rod study stability has actuality. In this case, the various modes of vibration and stability loss are possible. In this regard, the study was done by developed software, in which a technique of computer simulation of the oscillating motion of considerable length rotating rods under the action of axial periodic loads is implemented. Such software gives the possibility to model the oscillatory motion of rotating rods and determine the parameters by witch the dynamic stability loss of the studying system can occur. Using this software the diagrams with regions of stable and unstable motion of the rotating shaft were drawn for various parameters of the considered system. The process of oscillation is considered in space with account of inertia forces and geometric nonlinearity of the rod. It is shown, that on certain rotational speeds and frequencies of vibro-impact load there are ranges of unstable motion where the run of equipment can inevitably lead to destruction. The obtained results are analyzed. The conclusion about the possibility of running the equipment in certain frequency ranges is made.