That's an interesting problem. I would not suggest shot peening becaus that would accelerate your corrosion problems. Ultrasonic treatment could be a fisible solution. To your questions:
whatever treatment you do to existing cracks you have to make sure that their lengths are reasonable short otherwise shot peening or anything else would not work.
The under stress blades should be either examined through FE or by experience.
The problem can be solved with 1 year of research plan.
Sincerely
Dr. Chris A Rodopoulos
[email protected]
