The Application of Modal Analysis for Dynamic Systems of Ship’s Shaft Lines

The article is devoted to the use of modal analysis in the calculations of ship shafting. The methodology and results of an experimental study of bearing wear surfaces are presented. The applied optical restoration scheme makes it possible to obtain high-precision digital models of objects due to synchronous shooting of the object with cameras. The measurement results were obtained by processing with specialized software. The results obtained are a complement to the method for determining the elastic force acting on the shaft from a bearing that is unevenly worn along its length and has a variable clearance. Based on the obtained wear values, a solid model was built and the natural frequencies of transverse, torsional and longitudinal vibrations were determined. For the constructed model, the shapes of natural vibrations for practically significant frequencies were obtained. It is noted that bearing wear affects not only the displacement of natural frequencies, but also the shape of vibrations. The results obtained in the work are an addition to existing calculations when designing and assessing the reliability of a ship power plant.