I suspect that the turbine design is one that already has been...

I suspect that the turbine design is one that already has been used and is being used; I doubt that they have to go through many iterations at all. Yet, being manufactured previously, now it is printed and mostly needs to be time tested to collect data on life-span. This data would then be compared with avg life-span of manufactured turbines. The time-testing may be addressed by printing many of these turbines, flying them frequently and over extended periods whilst comparing the stress results to data of manufactured ones and seeing whether the same issues develop with the printed ones, how quickly and their location on the turbines. I suspect and hope that these results would be in much sooner than later.