| About this Abstract |
| Meeting |
Materials Science & Technology 2019
|
| Symposium
|
Failure Analysis: Industry Specific Failures
|
| Presentation Title |
13-8Mo Galling Induced Fatigue |
| Author(s) |
Eric Ross Allred |
| On-Site Speaker (Planned) |
Eric Ross Allred |
| Abstract Scope |
A340-200 Nacelle Thrust Reverser System includes 4 Blocker Doors which are utilized to slow the A/C after landing. The Blocker Door is lock when the A/C is in flight by a Primary and Secondary lock to prevent inflight deployment of the Door. The primary lock is a mechanical lock which includes a 15-5PH Shaft and 13-8Mo Cam. After approximately 20 years in service, Cam failures were observed. The primary mechanism of the cam failure was fatigue cracking initiated by galling and a stress riser (Kt) resulting in failure of the cam. Galling initiated between the 15-5PH H1025 Shaft and the 13-8M H1000 Cam due to vibration and small relative motions between the two components. The failure of the Cam was attributed to a design load which was not accounted for in the original design, a geometric Kt, and galling causes by relative motion between the cam and lock shaft. |