Hydroelasticity of a 3D floating body using a semi analytic approach in time domain

Abstract

A semi analytic three dimensional time domain method is developed to predict the hydroelastic effect due to wave induced loads on a floating body. An Euler–Bernoulli beam with analytically defined mode shapes is taken into consideration to represent the structural response. The hydrodynamic forces are obtained in time domain through impulse response function, and the Duhamel integral is employed in order to get the structural deflections; velocity etc. The hydrodynamic and structural part is then fully coupled in time domain through modal analysis for the solution of the hydroelastic problem. A rectangular barge with zero forward speed is taken for analysis. To check the effect of structural stiffness in force and moment calculations, structural responses, shear forces and bending moments are calculated for different stiffness factors. It is seen that structural flexibility plays an important role for calculations of shear force and bending moment. For validation, the computed results have been compared with other published and available results obtained by different numerical methods and satisfactory agreement is found. The present semi analytic technique appears to be time efficient, robust and could be a very useful tool in predicting the hydroelastic effects in shear force, bending moment, structural deflection at initial design stage.