You're correct that restarting simulations can save considerable computational time and resources if multiple simulations share common steps initially. Abaqus provides a restart feature that allows the restart of analysis from any previously completed step or increment in a preceding analysis.

As you are facing an issue due to the change in the blade's location in the sixth step, you need a solution that allows for the modification of your model (i.e., the blade's location) between the fifth and sixth steps, and yet still enables you to restart the simulation from the sixth step.

Abaqus allows for such model changes in a restart analysis, but there are restrictions on the kind of changes that can be made. Changes like modifications to boundary conditions, load magnitudes, or material properties are allowed in a typical restart analysis. However, changes to the model geometry or topology, like moving the blade in your case, are usually not allowed.

One possible workaround would be to model all 20 blade positions in your initial simulation but activate them in sequence in subsequent simulations. Here's how you might do that:

Remember, this is just a workaround and may or may not be feasible, depending on the specifics of your simulation. You might also need to modify the workaround based on your requirements.

In conclusion, while Abaqus allows for certain modifications during a restart analysis, the changes you're trying to make might not be compatible with this feature. You might need to resort to alternative modelling techniques to achieve your goal. If you're still facing issues, I recommend contacting Abaqus support or consulting the Abaqus user manual or user community for more specific guidance.