PDA

View Full Version : Contact Simulation NX 5



bfleck
01-04-2008, 05:29 PM
I have used other FEA packages in the past, but now I am using NX 5 with Advanced Simulation. I dont know what it is with UGS, but I think their help files and tutorials are poor. I would like to know the difference between Surface Contact Mesh and Surface-to-Surface Contact and when to use one over the other.

bluehelmet
05-09-2008, 11:16 PM
In my experience NX handles contact meshes very well. The autofind features in NX 5 is very powerful and lets you simulate assemblies extremely quickly. Here is my two cents:


Surface Contact Mesh requires that you have two meshed faces with relatively matching nodes on both faces in order to create a contact mesh that keeps track of the distance between them and stresses them accordingly upon contact.


Surface-to-surface contact is applied to two, unmeshed faces and creates a contact mesh between them upon mesh generation. You have to specify a contact vector for your model to solve in most solvers when using this option.


Usually what I do is the following:


- if two parts are touching and will not separate, e.g. two bolted members, I use the mesh-mating conditions to glue the two faces together. Usually works very well with assemblies.


-if two parts WILL touch upon application of loads, e.g. bolt heads inside counterbored holes,I apply surface-to-surface contact conditions between them. I try to avoid the contact meshes mostly because I've had good experiences with the above rules of thumb.


The NX pre/post processor is one of the best out there. Unfortunately making design changes means going back to the Modeller, making the changes and THEN losing all your contact conditions http://mcadcentral.com/smileys/smiley7.gif. But oh well, given that it reads your CAD data perfectly and generates FE models with contact quite well, I really shouldn't complain. http://mcadcentral.com/smileys/smiley1.gif


Good luck!