Yoghourt problem 1

[lukasz2]

Hi, I created model of plastic yoghourt mug to my non-linear analysis in Ansys and in following calculations I want to add the internal part (yoghourt) to compare the behavior, displacements etc. What is the simplest way to modelize it? I should create solid inside and use contact elements?? Or there are simplest ways???

Thanks in advance.

 

[Stringmaker]

What's the point of your analysis? Do you really think the interaction between the yogurt and your mug is worth considering? I think it probably isn't...

 

[lukasz2]

The point of this analysis is buckling, I did eigenvalue analysis and non-linear analysis for mug and now I want complicate it by filling this mug by low density substance.

 

[Stringmaker]

I don't understand how yogurt which in all likeliness will subject the mug to a small internal hydrostatic pressure will buckle the mug?

I'm curious, what purpose does the mug serve? What if it does buckle? From the little I know about the problem it seems that there is no way it could...given that you're pressurizing the mug stress will be tensile and should not buckle it from that loading alone. When would buckling occur? During shipping when others are stacked on it?

 

[lukasz2]

I’m trying to find force magnitude needed to buckle mug. To do this I put pressure on the top and adding yoghourt inside I want compare behavior and buckling occurrence with and without yoghourt. Thanks your answer I have an idea to put pressure on the internal side of mug which will simulate yoghourt pressure. It will eliminate model of substance inside.
This yoghourt mug is the subject of my project, doing this I'm learning Ansys environment so I beg you for understanding

 

[Stringmaker]

You'll want to do the following:

- Run a static analysis first with hydrostatic pressure applied to mimic the yogurt. Through tables or arrays you can easily apply this to make pressure vary linearly with height.

- Run your buckling analysis next with prestress from previous analysis. Check out PSTRES command for this.


The buckling analysis I do is done with LS-DYNA because of strain rate and inertial effects. Because of this I'm not a great source of info doing it within Ansys. However, I'd check out the documentation. You will moste likely see quite a difference between linear and nonlinear buckling analysis results. Nonlinear buckling load should be more realistic. As always, analysis should be verified with actual testing!