# Static structural analysis on a solid sphere?

1. Mar 30, 2016

### Mitra Lanka

Could you perform Static structural analysis on this solid sphere? No contacts to be used.
I do not have any specific boundary conditions(unable to apply constraints to a complete solid spherical body)
All i know is the pressure that needs to be applied.

You could consider a smiley ball on which pressure is applied.
I do not know how to apply constraints

I am using Ansys workbench. Please let me know how to proceed further

2. Mar 30, 2016

### NumericalFEA

When there are no constraints applied, the global stiffness matrix becomes singular, so no solution can be obtained.
If you know for sure that your solid sphere is in equilibrium and if you believe that the loads' distribution is such that the geometrical center point of the sphere remains unmoved, apply constraints in all three directions to the node corresponding to the center point and, possibly, to a couple of neighboring nodes. That would make the global stiffness matrix non-singular.

3. Mar 30, 2016

### Mitra Lanka

Thanks for responding!
As the solid sphere is axi-symmetrical in x,y,z axes. Can i perform stress analysis on the symmetrical part of sphere?
This is just to view and constrain nodes near the center point.

Is this the right way of approach?.

If it is not the right approach,
then how do we constrain the center of a complete solid sphere in ansys workbench. Is there an option to do it?

Last edited: Mar 30, 2016
4. Mar 31, 2016

### NumericalFEA

Аs long as the load is symmetrical with respect to some plane passing through the center point, you can work with just a half of the sphere. In that case, the center point will be exposed. However, there is also a very important thing to do: each of the nodes that belong to that plane of symmetry must have a constraint applied such that it would completely restrict translations of those nodes in the direction perpendicular to that plane of symmetry.

5. Apr 6, 2016

### Mitra Lanka

Thank you for the response. :) . It worked for me.

6. Apr 6, 2016

### NumericalFEA

I am glad to hear that. Good luck !