zero reaction force in ABAQUS/STANDARD Contact simulation

[cyano84]

Hello everyone,

I am running a load controlled spherical ball contact on a plate. I am using an axisymmetric model of the plate and axisymmetric analytical rigid ball. The plate is simply supported on the edge, so U2=0 on the bottom rightmost node on the plate.

I have a RP (reference point) at the center of the ball where I am applying a small displacement at first to establish contact and then load after removing the initial displacement. The analysis is running till completion but I want to extract Reaction Force at RP, which is always 0! Obviously that is not possible. What am I doing wrong?

Thank you for your help! - Sayan

 

[corus]

Check the reaction force at the restraint as that will be equal to the reaction force of the RP.

 

[cyano84]

What do you mean by "at the restraint"? The reaction force at the RP is 0 and also at the contact point i.e. top leftmost node where the initial contact is happening.

 

[corus]

The restraint is where you set U2=0

 

[cyano84]

Thank you so much! The RF at the restraint is exactly equal to the applied load. I am happy now

 

[corus]

The reaction force at the RP was probably zero as the internal forces of elements sum to zero in a static analysis, except where there's an imposed displacement/restraint.

 

[cyano84]

Right. The reaction force at the contact point is also 0, which was throwing me off. In fact RF=0 pretty much everywhere except at the restraint. I guess if I want to calculate the reaction force at the contact, I have to calculate the contact stresses and work it out from there. It is probably treating it as internal nodes and not showing any RF.