Determination of the natural ship hull vibration modes by means of the Vlasov functions

Abstract

The general description of a method of ship hull vibration analysis is presented. Based on the Vlasov’s theory the differential vibration equations were formulated of a ship hull modelled as a system of linear, elastic orthotropic shells of multi-circuit cross-sections, floating on the ideal fluid. An algorithm for the generation of the motion equations and boundary conditions, as well as for the numerical integration of the motion equations was elaborated. The method enables to determine the hull response to excitation caused by the system of harmonic forces as well as to calculate the natural modes and natural frequencies of vibration. Examples of numerical calculations compared with experimental results are included for two types of hulls.