Modal properties for a small ship - A comparison of Vlassov-Timoshenko beam theory and two dimensional FEM modelling with full scale measurements

Paper in proceeding, 1984

When analyzing the dynamic properties of a ship performing bending or torsional vibrations,
the determination of the ship's modal properties is an important intermediate step. In this
paper the hull is modelled with a two-dimensional finite element method for vertical modes
and with a Vlassov-Timoshenko beam model for vertical and coupled torsional-horizontal
modes. The entrained water is calculated with a finite volume method and represented so as
to be independent of mode shape. The resulting natural frequencies and mode shapes are
then compared with extensive full scale measurements. The correlation between
measurements and calculations is essentially the same for the two models, with a mean
discrepancy of about 6%.