Static structural analysis on a solid sphere?

AI Thread Summary
Static structural analysis on a solid sphere in Ansys Workbench requires applying constraints to avoid a singular global stiffness matrix. Without specific boundary conditions, one can constrain the center point and neighboring nodes to maintain equilibrium. If the load is symmetrical, analyzing only half of the sphere is feasible, provided that nodes on the symmetry plane are constrained appropriately. This approach allows for effective stress analysis while ensuring the model remains stable. Properly applying these constraints is crucial for obtaining valid results in the analysis.
Mitra Lanka
Messages
4
Reaction score
0
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
 
Engineering news on Phys.org
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.
 
  • Like
Likes 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:
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.
 
  • Like
Likes Mitra Lanka
Thank you for the response. :) . It worked for me.
 
I am glad to hear that. Good luck !
 
  • Like
Likes Mitra Lanka
Thread 'Physics of Stretch: What pressure does a band apply on a cylinder?'
Scenario 1 (figure 1) A continuous loop of elastic material is stretched around two metal bars. The top bar is attached to a load cell that reads force. The lower bar can be moved downwards to stretch the elastic material. The lower bar is moved downwards until the two bars are 1190mm apart, stretching the elastic material. The bars are 5mm thick, so the total internal loop length is 1200mm (1190mm + 5mm + 5mm). At this level of stretch, the load cell reads 45N tensile force. Key numbers...
After over 25 years of engineering, designing and analyzing bolted joints, I just learned this little fact. According to ASME B1.2, Gages and Gaging for Unified Inch Screw Threads: "The no-go gage should not pass over more than three complete turns when inserted into the internal thread of the product. " 3 turns seems like way to much. I have some really critical nuts that are of standard geometry (5/8"-11 UNC 3B) and have about 4.5 threads when you account for the chamfers on either...
Back
Top