Ok, it turns out that it’s necessary to create an arbitrarily named node-based surface for the bar based on the node set used for the initial condition to make it work in 2D (due to expansion issues):
*SURFACE, NAME=bar_surf, TYPE=NODE
bar
*INITIAL CONDITIONS, TYPE=VELOCITY
bar, 1, -5000
Now I just have to figure out the parameters allowing for a reasonable runtime and accuracy of the contact force with my data (it’s Abaqus benchmark model). But at least I don’t have to use 3D so it shouldn’t take that long.
When I asked Guido about rigid body in axisymmetric explicit dynamics models, he said:
A rigid body condition is nonlinear due to the rotation. Axisymmetric elements are expanded and therefore, linear equations are introduced between the two sides of the 2-degree segment. Therefore, linear and nonlinear equations will depend on each other. I do not recall any more why it is not allowed in an explicit dynamic calculation, however, it may not be easy to remove this limitation. Increasing the E-modulus of the rigid body may be an option, however, it will decrease the time step (unless you fix the minimum allowed time step).
It must be the same with plane stress/strain and shells.
It’s because you have:
*Output, Frequency=1
It should be 100 or 1000 in explicit dynamics due to a large number of increments.