All Reaction Forces are Zero

[fruton]

Hello all,

I am a little confused with abqaus, I have parts in contact which show stresses and contact pressure, however all my Reaction force plots RF are zero and I don't understand why? Can anyone help? Many Thanks.

 

[corus]

Reaction forces only show at restraints, elsewhere the forces must balance and so are zero.

Tara

 

[fruton]

Oh of course, thanks corus. Also, I just wanted to check with others. If I apply contact through displacement. I assume this to be equal to applying an equivalent force load, assuming the rate of displacement and loading are also equal. Am I correct in this? Thanks.

 

[corus]

Normally displacement is related to force given by the stiffness (assuming elastic behaviour). With contact, however, there may be some redistribution of the load so the effective stiffness may change.

Tara

 

[fruton]

As I am modelling my material beyond its elastic limit is it then not a good idea to use displacement control and try to use load instead? Then I tend to have problems with convergence in standard. Thanks.

 

[corus]

Displacement is better as you're more likely to get a solution. It's better, thougj, to apply some small displacement to get contact and then apply your loads in another step.

Tara