engleski

Coupled flexural and torsional vibrations of thin-walled girders

Investigation of coupled horizontal and torsional vibrations of thin-walled girders related to container vessels is presented. Differential equations of coupled vibrations of a prismatic beam with open cross-section are derived. The equations are solved analytically by direct integration and by variational method. In the former case the frequency equation is reduced to a polynomial of the fourth order. In the latter case beam deflection and twist angle are assumed in the form of series of natural modes of uncoupled vibrations of free beam including warping. The variational method manifests very fast convergence and high accuracy. Application of the developed methods is illustrated on the case of a prismatic pontoon with cross-section of a container vessel. The same numerical example is used for checking 1D FEM mathematical model and code developed for analyses of real structures of container vessels with variable cross-sections.

container ship ; beam model ; coupled vibrations ; analytical solutions ; energy method ; FEM

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