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Force-controlled loading in ABAQUS with a set maximum displacement

Greetings to all users.  I am using the parametric study option of ABAQUS to run a series of spherical indentation problems.  Each model in the series uses a different set of rate-dependent plasticity material parameters and I am trying to compare the results of my ABAQUS runs to some experimental data.  The experiments consist of a loading portion, a dwell at peak load and an unloading portion.  The loading segment was performed with an exponentially increasing load on the sample, but when a prescribed displacement is reached, the loading portion stops and the next step, the dwell, begins. 

I am trying to simulate these boundary conditions, but there appears no easy way in ABAQUS to run a load-controlled test with a maximum displacement constraint.  I have received a suggestion of using the RIKS approach in ABAQUS (which I have no experience with), but I am told that I cannot have any other step follow this step.  In this case, my dwell and unloading portions will have to come from a restart analysis.  But, the disadvantage of using the restart is that I have to run each restart case in my parametric study manually.  There appears to be no way of using the parametric study option and making it choose the appropriate 'oldjob' for each restart run.  If I have to do this manually, it pretty much kills the advantage of using the parametric study option, which is quite crucial because I have several other parametric studies to run.  Understandably, I am not too fond of this idea.

I have to mention that I have tried to use a kinematic coupling between the node where the load is applied and a rigid reference node to enforce a maximum displacement constraint.  In this case, the displacement constraint is enforced, but the load continues to increase till the end of the step, and this is obviously not desirable either.  Moreover, since the material response is time-dependent, I really don't want the material to spend any time under a load that is not part of the experiment. 

I am at a dead end for the time being and needless to say, I would appreciate any thoughts my fellow mechanicians might have on this.

Best Regards,

Shankar

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