Learning Forum

[TBEINEMA]

Hi all,

I have a question regarding the modelling of a rectangular floating plate. The situation is as follows: a lightweight rectangular plate is not fully submerged and receives at specific locations forces or displacements derived from a separate program.

The aim of the simulation is to be a fast analysis. A modal analysis with two way fluid-structure interaction (FSI) is therefore considered. Due to the coupling with the external program it is preferred to do this simulation using APDL, (Also to compare the found wet eigenfrequencies and modes to those found previously with a dry modal analysis (in vacuo). Finally, I wish to extract the Structural mass, Added mass, Structural stiffness and hydrostatic stiffness matrices, and final displacements of the previously mentioned nodes.

I have been reading through the simulation guides by Ansys and due to the large amount of information and the inexperience on my part I request some guidance on how to best implement this.

The question therefore is:

It seems to me that the acoustic fluid structure analysis is the proper way to do this, but I am not sure which analysis type to choose. Harmonic, Modal, etc. Any guidance on other things to consider in the simulation are also very much appreciated.

[dlooman]

The analysis type is based on how the loading varies with time. If it's sinusoidal then a harmonic can be used. A modal analysis can always be used to determine the natural frequencies and isn't a function of the loading. For an FSI model it is necessary to use the damped modal solver. An example is VM177 in the APDL Verification Manual. Extraction of matrices can be done with APDLMath.