Learning Forum

[Reno Genest]

nnYes, I prefer modifying the soft option before I mess around with the contact stiffness. The soft option will change the way the contact stiffness is calculated and this changes the contact stiffness.nFor a contact with similar material densities and stiffnesses, soft=0 or 1 should work fine. But, you have a rigid body which can affect the contact. You can try with the base plate as a deformable body instead of rigid. You could remesh the plate with larger elements (just a bit larger than the sphere) so that the bottom plate elements do not affect the time step. This way, the calculation time will not increase by much. This will show you if the rigid body affects the contact or not.nSoft=2 uses segment based contact detection; it looks at slave segments (in other words faces of elements) penetrating master segments (and vice versa for surface to surface contacts) instead of nodes penetrating segments. So, in some situations, soft=2 will be better because of segment based contact detection. For your case, nodal detection should work fine though.nWhich contact are you using? The AUTOMATIC family of contacts are the newer generation and are recommended. They tend to be more robust. I would try *CONTACT_AUTOMATIC_SURFACE_TO_SURFACE. A surface to surface is a two way contact; that is, the contact detection is looking for penetration from slave into the master and also the master into the slave. It takes a bit more time to compute, but is more robust.Also, you have many ways of specifying the slave and master sides. You can use the part ID (option 3). Sometimes, you get better results when specifying segments (option 0) to define the slave and master sides of a surface_to_surface contact. So, you can try that as well.Let me know how it goes.nnReno.n