HELP_Abaqus constraints problem

[haiyue]

Hi,all

I am planning to replicate a DMA test( rheological test) using abaqus. I want to deform my "sample" in the first step and followed by applying the rotation on the top surface at the second step. I know the kinematic coupling constraints is what I should use to apply rotation in abaqus. The problem is , the coupling constraints seem to be active from first step, but that is not what i want .

SO my question is how can i do to activate coupling constraints just in the second step? Using user defined MPC? or using constraints equation instead? Anyone has a good idea?

Thanks in advance,