When we do our FEA study, there’s always some need to determine the total reaction force on some part. For example to obtain the maximum load of a round bar, we’ll surely need the reaction force on the load.

Or just like the following example, to determine an inserting force.

When we output the force, we normally choose output reaction force for any nodes that has been applied displacement boundary condition. But that will results getting groups of forces and require some data add up, sometimes when the geometry is irregular, the data process may ends up impossible. In this instruction, we will constraint all these nodes as one so the force on this one node will represents the total reaction force on this part.

This is the geometry example, already meshed and add interactions to simulate the contact.

First we build a node set: Load, choose every node you intend to add BCs on but leave one node out of this set.

Then we build a node set: RF , this set only contains one node you just leaved it alone.

Next, Constrain Load to RF, choose the Equation type and input values as the figure.

The coefficient is always a pair of number adds up to zero, so 100,-100 is also ok.

DOF is just as ABAQUS defined, 1 is x axis, 2 y, 3 z, 4 x rotation and so on.

Usually I suggest to constrain 1 2 3 DOF by build 3 equation constrains.

Then you can add your BC on to that RF node only, since the nodes are constrained together, this is the same thing with add your BC to all the set RF and Load.

When you finished the job, output reaction force on the RF node, you will get the reaction force on the whole doughnut part.