Allowance for shear distortion and rotatory inertia of ship hulls

The response of a ship to waves and to propeller excitation (as well as its distortion in still water) may be analysed in modal form by using a linear theory. For symmetric responses the approach has been discussed in terms of a “hull girder” treated as a simple beam. The same is true of uncoupled bending in antisymmetric motion. Simple beam theory has also been adapted for use in “coupled bending and twisting” responses of hulls with large deck openings. The theory has not, hitherto, embodied an allowance for the effects of shear distortion or rotatory inertia. It is shown in this paper how those effects may be allowed for in the analysis of symmetric response, that they do not alter the form of the more rudimentary analysis and that the response lends itself to a convenient matrix formulation.