Dynamic Measurements of Coupled Vibrations of Ship's Shaft Lines

The work is devoted to an experimental study of the coupled torsional and transverse vibrations of a ship's shaft lines. The classification of the loads required for measurements affecting the operability of the shaft line are given. It is noted that analytical calculation methods do not allow to fully taking into account the actual conditions of shaft loading due to their random nature. The results of an experimental study of the vibration parameters of the shafting of two tugboats by the method of dynamic strain measurement are presented. The presence of a region of dynamic instability of the shaft during torsional and transverse vibrations at one operating speed has been established. The results of measurements of the actual mechanical stresses on the shaft are presented. The effect of acting equivalent mechanical stresses on the shaft performance is estimated. The results of studies of coupled oscillations on an experimental setup are presented. The registration of tensile, compression and torsion deformations of the shaft line was made on the basis of the author's method of the dynamic measurement. According to the presented tensograms of vibrations of the shaft line, it is concluded that there are zones of dynamic instability of the shaft line. The results obtained in this work are an addition to the existing methods of dynamic measurements and can be extended to other technical systems containing a heavily loaded shaft.