×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Split Sleeve Cold Working
2

Split Sleeve Cold Working

Split Sleeve Cold Working

(OP)
A few years ago there were reports floating around industry about microcracks forming in 7050 series plate in the ST direction when Split Sleeve Coldworking was applied to a hole.

Does anyone know these report numbers?  

Did SAE or AIAA have similar reports?

Does anyone else remember this?  Everytime I bring this up to someone I get a mystified look.

RE: Split Sleeve Cold Working

I have installed several thousand sleeves in A-10 aircraft lower wings and I can't remember the engineer name who was head of the porject.  However if you contact Tech Support at Wright Patterson AFB they can do some research for you and find the answer I am sure they have helped me several times.  They can be reached at:

Tech Suport
1864 4th street
FTE1
AFRL/XPTT
WPFB, OH   45433

1-800-203-6451

Stache

RE: Split Sleeve Cold Working

Stache..

White rabbit was asking about hole cold working using the split-sleeve-mandrel system [Ah-la Fatugue Technology Inc].

I think You are refering to installation of fastener-sleeves [MIL-DTL-85068/*] for oversize-hole repair using nominal size fasteners.

Boeing has significant restriction on FTI split-sleeve hole cold working [SSCX] in the ST orientation. Reason is as follows...

Ref MMPDS or MIL-HDBK-5 data for 7050 alloy allowables. In the ST orientation "e" can vary from ~10% to ~50% of "e" in the L orientation which are not all that high (~8%-to-12%). This is BAD from the perspective that most cold working requires 3%-to-6% hole expansion just to gain 1%-3% residual (compressive) strain (~increase in hole dia) after CX. Obviously 4% strain on a grain orientation with only 3% strain [at failure], is guaranteed to split (crack) the part on the suseptible grain orientation.... or induce such high residual stresses that it will split (crack) in-service.

Note: Boeing stress engineers are required to use a substantial "knock-down factor" for certain ST calculations involving fasteners [proprietary].

Regards, Wil Taylor

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources