Learning Forum

[deepesh.p.gurdasani]

In an assembly of few parts, I am able to see Ixx, Iyy, Izz AND C.G for each part separately but unable to see it for combined assembly when I click on 'Geometry'. Is there any way to get MOI and C.G for whole assembly combined ?

 

Thanks in advance

[Ankush Choudhary]

Hi Deepesh,

Please check out the below video to achieve this.

https://www.youtube.com/watch?v=-UmTcGUD6lk

The other option is to create a multibody part, and then you can get the information from geometry details.

[deepesh.p.gurdasani]

Thanks for the video link but to check overall C.G and M.O.I I will have to run a dummy analysis iteratively which could be time consuming, isn't it?

1) After creating multi body part, would'nt the mesh get messed up? because isnt it mainly used for getting conformal mesh similar to share topology?

2) Here actually I am not talking about splitting a single component and then moving the splitted parts into new component (which would eventually create multi body part. Here I am talking about totally two or more different parts where I want to check overall C.G and M.O.I.

 

Please correct me if I am wrong.

 

Thanks

[Ankush Choudhary]

Hi Depeesh,

Yes, you have to run a dummy model to get an overall C.G. However, it is not necessary that, for a multibody part, you have to use shared topology. You can create a multibody part without shared topology as well. You can quickly create a multibody part for those parts only for which you want to check C.G. without using shared topology.

The other option is to use selection information, select the bodies for which you need information, and then use selection information to get the desired values.

[deepesh.p.gurdasani]

I selected 3 parts in spaceclaim and selected 'Move to new component'. Spaceclaim isn't anyway showing M.O.I and C.G even for that newly created component (that includes 3 parts), in mechanical also, these individual components' name now has their group name that was created in spaceclaim and even in mechanical now when I click on those same 3 parts, it doesnt show combined M.O.I and C.G.

[Ankush Choudhary]

Have you tried the selection information option?

[deepesh.p.gurdasani]

Yes but selection information mainly shows C.G (Combined as well as individual) but not M.O.I.

 

[Ankush Choudhary]

You can easily get this information in SpaceClaim, as shown below. To get an accurate result for MOI, make sure to define the density of the material in spaceclaim.

[deepesh.p.gurdasani]

Ankush, is this feature in the latest ANSYS version? because I can see only centre of volume and principal moment (with unit of mm^5 and not kg mm^2)

[Ankush Choudhary]

Hi Deepesh,

Please assign the density material property to the bodies in the SpaceClaim. Then you will get the correct units.

[deepesh.p.gurdasani]

Thanks Ankush, will check this.

Other query I have is of, if there is a point mass (Mass and M.O.I given to it) added in 'mechanical; 

How can point mass participate in this whole M.O.I and C.G ? Can we see point mass' C.G and M.O.I added in overall structure's M.O.I and C.G just like it shown in the image uploaded by you ?

[Ankush Choudhary]

If you want to include the point mass, then there is no other option; you have to follow the approach that is shown in the video.