Hi everyone,
I'm trying to solve a Hertz contact problem between two spheres.
My model is two elastic spheres that are initially in contact. The spheres have same mechanical properties (E,v,...) and same geometry.
I use a surface-to-surface contact with a "Hard contact" normal behavior and frictionless.
If I impose a Force to top of the spheres, the simulation doesn't converges. when I constrain spheres which they have only displacements in direction of implied force, It is converged; however, spheres move in direction of forces. How can I constrain them not to move and get results? If you have any tutorials or comments, please write or send me. If you have any articles or books about analytical stress modeling of spheres contact, would you please Introduce them to me.
I want to validate my simulation against the analytical solution that is defined for an applied load...that's why I really need to make my simulation work in this configuration.
Thanks in advance for your help.
Sir Hope u find this useful :
Was constrain for fixed support given at the bottom,the movement is due to unconfinement probably.
(for simplicity use of hemispheres instead of spheres and constraining the bottom can be done
or use another plate to constrain it from bottom if hemispheres are to be used)
Work on similar lines have been done using ANSYS
http://www.ijraset.com/fileserve.php?FID=1377
https://www.youtube.com/watch?v=zk4Xe_9AiKE
When you do not constrain the displacement of the others directions, I guess there must be rigid body displacement which is responsible for the in-convergence. If you are not interesting in friction, to simplified the problem with one sphere and a plate is a possible way.
Jamaleddin,
I like the book "Contact mechanics" by K.L. Johnson.
As for contact modelling in ABAQUS, I strongly recommend that you read the manual carefully. One advice which is given there is to use a small overclosure between the two bodies and then use "adjust to remove overclosure".
You still need to constrain the motion in the other directions if you do not have friction.
You also need a very fine mesh in the contact region for this to work out because the contact area is very small if the bodies are stiff, say steel. This area can be computed theoretically from your Hertz theory.
Hope this helps...
Mahir
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