Hard, review any relevant engineering topics that pertain to your interview. Prepare by solving hard though experiments, like how you would design a pressure vessel, how to make a beam stronger, etc.
Multiple rounds of interviews ending with an all day onsite interview. Asked questions about background, classic textbook problems, and coworker interactions. Very technical and difficult. Lots of time spent trying to understand your thought process
4 rounds, 1 with technical recruiter, 1 with engineer, 1 with manager, and onsite. first 3 are over the phone. onsite was the challenge, consists of presentation, one-on-ones, and tour.
Rigorous but fairly reasonable in my experience. The technical problems often has a twist but if you have strong fundamentals you should be able to perform well. The recruiter and interviewers I interacted with are all very nice people.