Part of my education is manufacturing engineering. Over the years I've been involved in countless metal forming operations and processes. One that seemed to jump into memory was explosive forming aft pressure bulkheads on commercial aircraft. We'd use a high explosive in water to squash and stretch a large piece of metal over a domed shaped form and flange it as well.
I could go on all night on examples of structural aircraft parts that are cold formed.
I'm with Don on this one. If the bulge is inspected and crack free, it is much stronger than before it was bulged. I say this because there is actual metallurgical industry standardized test data that can repeatedly substantiate this fact, not a gut feel. I can produce that test data, but my internet is down and I'm working from my cell iPad.
Last edited by Chuck H; 01/09/16 03:18 AM.
