surface-to surface contact VS. node-to -surface 2

[aminjamali]

I have solved a very simple contact problem using surface-to-surface contact (CONTA171/TARGET169) elements and also using node-to-surface (CONTA175/TARGET169). I compared the results, they are different--not significantly but well I am concerned. Any idea?

Thanks

 

[meshparts]

I would say, the surf-to-surf contact is better then the node-to-surf contact.

The first one takes into account the form shapes of both contact and target surface. The second one only takes into account the form shape of the target area.

The node-to-surf contact is useful when simulating for example a beam tip contacting a surface.

Alex

 

[Stringmaker]

Have you checked contact pressure and penetration to compare the two? Also, what is the contact stiffness for each method? What "difference" is it that you observe? Deflection? Stress?

As was pointed out previously, generally surface-to-surface contact is better for large contact areas.

 

[aminjamali]

Mihaiupb and Stringmaker,

Thanks for the notes. I have used identical stiffness values for both methods. I usually check strains (and then deformations and stresses) but I checked the contact penetration and pressure as you advised; I can say they are really (!) different, the strains are pretty close though (about +- 5% difference).

Thanks you guys