Learning Forum

[NavalArch]

Hello,

I have 20 individual structures connected with hinges. I was wondering how it is possible to select them all in the structure selection in order to see the motions of the whole structure not each connected one as you can see in the attached image.

Thank you in advance for any help in this matter.

[Mike Pettit]

Hello,

The Hydrodynamic Diffraction analysis can be performed with or without hydrodynamic interaction effects. If you do not include interaction, a separate hydrodynamic database will be generated independently for each structure; in the Pressures and Motions result you will only be able to plot results for one structure at a time.

However, if you do include interaction, the radiation damping and added mass calculated for each structure (and subsequently, RAOs etc) will account for the presence of the other structures in the interacting group. Then, when you plot Pressures and Motions results, you do so for the whole group.

In your case, where multiple structures are joined together in close proximity, I would recommend performing the diffraction analysis with hydrodynamic interaction turned on: click on the Hydrodynamic Diffraction Structure Selection, then click Interacting Structure Group 1, and select all of the structures in the Graphical Window. Then click Apply in the Interacting Structure Group 1 field.

I hope this helps.

Mike

[Mike Pettit]

I should add: the Hydrodynamic Diffraction analysis does not include the Joint objects that you have defined - these are only used in Hydrodynamic Response calculations. If you want to model the effect of the joints in the Hydrodynamic Diffraction calculation, you should create Connection Stiffness objects (under Connections) to represent the linear stiffnesses between each structure, which you can set as large values for the translational terms.

Mike