Learning Forum

[nabhan25]

Hi Everyone,

Im currently dealing with a surface structure for hull section. Since, it has lots of surfaces, I have make the geometry as one part after the mesh connection & connection not work as I predicted. 

However, after making a part and update the geometry in "Model", some of the surfaces disappear. Anyone has encountered this? and know the solutions? 

With this warning, " Mass properties (volume, surface area, centroid, moments of inertia) may be inaccurate due to missing face facets: Part"

 

Cheers. 
NZ

[nabhan25]

[Rob]

Check the surface in DM: is it valid? How many faces have you got?

[nabhan25]

Hi Rwoolhou,

It seems fine in the DM as per 1st image. Total surfaces= around 269 and definitely will be increase as Im going to model the whole ship. 

I been trying different approach, for instance; 

(1) convert it in different format (tried igs, stp, rhino and even import it into the spaceclaim) 
(2) Split the surface in the CAD model (Im using Rhino) into smaller faces
(3) Give a named selections and bring it into the model 
(4) Simplified the model by removing small items such as flanges
(5) Make into 1 part

Any advice on dealing with large & complex surface/shell structure?

Cheers, 
NZ

[peteroznewman]

Try meshing in the Model, maybe the mesher can see a hidden face?

[Nasrul Hassan]

Hi can u mesh from DM? My itention is to mesh my model part by part which having to import the model each time. 

[nabhan25]

Hi Peter

Proceed with meshing?  Alright, Will give a try on that.

But, thats mean I cant assign thickness in the Model for the missing surface? Am I right? 

One question, If i make a part for whole structure, that indirectly make the whole structure bonded right? so, no mesh connection or connection required. Am I right? 

Any other on dealing with large surface/shell structure? 

Cheers, 
NZ

[peteroznewman]

In DM, if you put all the surfaces in a single part, that engages Shared Topology by default. That means surfaces that have coincident edges will have shared nodes on that edge and so the elements on each surface will be connected without the need for any contact.

I will take a look at the geometry if you want to upload the .wbpz archive file.  Say what version of ANSYS you are using.

[nabhan25]

Hi Peter,

Thanks for your time. Kindly refer attachment for the wbpz file. 
In this model, few faces is missing..

Just for your info, everytime I re-upload the model. The missing faces location will be change too. 
and for some unknown reason too, the "part" seems not working properly which create large deformation if the analysis work.

If there anything weird things happening in the analysis, feel free to raise it up. Im open for discussion and improvement.

Ansys Version: 18.1 

Cheers,
NZ

[Rob]

That sounds like there's a translation issue: what happens if you read the CAD back into Rhino after exporting in (for example) stp?

[nabhan25]

Hi Rwoolhou,

The CAD model perfectly fine in the CAD & the design modeler as per image below. But, it became "weird" after moving towards "Model" for meshing & setup. 
Kinda stuck on meshing & boundary condition at this stage. 

Cheers Rwoolhou for you time,

NZ. 

[nabhan25]

On top of that, this also a warning when a missing faces/surfaces occurs. 

" Mass properties (volume, surface area, centroid, moments of inertia) may be inaccurate due to missing face facets: Part"

Cheers, NZ. 

[Nasrul Hassan]

Hi nabhan, may i ask if u model the section in rhino or directly from DM?im currently doing same type of model and seem to failed to mesh. My model in from rhino. Is there a way to mesh part by part in ansys so that i know which is the problem surface and adjust the mesh connection? Thanks