Reno Genest
Ansys Employee
,nnHere are my answers:n(i) Yes, you can scale the contact stiffness. See https://ftp.lstc.com/anonymous/outgoing/support/FAQ/contact_stiffness_adjustment for more information. Personally, I like to change the soft option when the contact is not behaving properly (large contact energy when the friction is zero). My go to settings now are soft=2, sbopt=3, depth=35, and pstiff=1. Note that soft and pstiff options will change the method of calculating the contact stiffness. Look at the manual for more information.n(ii) You can output the results d3plot every cycle (with or without a curve) when the contact is being establish. See *DATABASE_BINARY_D3PLOT in the manual for more information. With results at every cycle, you can see in LS-PrePost if the sphere is penetrating too much into the rigid plate. If the penetration is too much, you can increase the contact stiffness; a factor of 10 is a good start. Note that in real life there is no penetration between parts, but with an infinite contact stiffness, we get instabilities in FEA codes. See the link above for more information. I like to change the soft option instead of scaling the contact stiffness. nFor more information on contacts, see https://ftp.lstc.com/anonymous/outgoing/support/FAQ/contact.overview and https://ftp.lstc.com/anonymous/outgoing/support/FAQ_docs/contact.pdf.nTo improve your hourglass problem, you could try solid elform=1 with hourglass type 6 for the sphere. Or solid elform=-1 (fully integrated) which do not have hourglass problem. Here is more information on elements: https://www.dynamore.de/de/download/papers/forum11/entwicklerforum-2011/erhart.pdfnAt last, make sure you model the rigid body with regular material density and Young's modulus using *MAT_RIGID. For soft=0, the bulk modulus of the material in contact is used to calculate the contact stiffness; if you have a very high value of E, then the contact stiffness will be artificially high.Reno.