Learning Forum

[Nasrul Hassan]

Hi, I'm want to perform a shafting deflection due to hull sea water bending in ansys, but I don't want to model the whole ship structure since it will take alot of time and geometry editing. Is there a way to import the bending moment obtain from AQWA, directly to ansys mechanical? So i can just model the section of interests. Hope someone can help. Thanks

[Yu Bi]

Aqwa can do it by modeling the whole structure as a multi-sectional hydrodynamic interaction model. In Hydrodynamic Diffraction analysis, each section is considered as one structure (or one part), and the multi-sections are in a hydrodynamic interaction structure group and locked to each other.  In the time domain Hydrodynamic analysis, these sections (structures or parts) are linked by rigid connectors.  In Aqwa to Static Mechanical loading mapping for the FEM structural response analysis, the interested section could be modeled by a FEM model, the reaction forces/moments on the two ends which are the bending moments and shear forces at the section ends) together with the hydrodynamic pressure could be mapped on the FEM model. 

In other words, in Aqwa, you need to model the whole ship hull with sectional cuts. Aqwa only needs the hull surface, with no need for internal beam structures. Lock the hull sections and put all the hull sections in one hydrodynamic interaction group when calculating the Hydrodynamic Diffraction analysis. Then define fixed joints between hull sections and run time domain Hydrodynamic Response analysis. Using Hydrodynamic Pressure Add-on maps the loads from Aqwa Hydrodynamic Response analysis to Static Structural. In the Static Structural model, you can only model the hull section you want to analyze. 

Hope this helps.