02-20-2016, 07:32 AM
RE: David 1/31/2016 ‘Unclear to me where in the flaperon report he got info on evidence of fatigue from and it will be interesting to see what the French find.’
Agree it will be interesting to see what the French publish. The Flaperon Failure Analysis (Rev 2.0) does not contain all the analysis otherwise it becomes way too big. The above fatigue comment by David is a very valid and astute statement.
The investigators will have an easy time determining fatigue vs shear regimes on the failure points. However, observation from La Reunion photographs is a greater challenge. Rather than going into a long dissertation on fatigue vs. shear, perhaps the following, conceptual level, explanation sheds some light.
Reference Exhibit 5 on pg 6 of 33 http://www.duncansteel.com/archives/2209
Observe the remains of the Inboard inner bracket ear. In a simple massive shear event there would be only one type of breakage on the inner ear that occurred in a fraction of a second. However on the La Renunion Flaperon Inboard inner bracket ear there are two distinct types of metal failure evident on the inner bracket ear. Type I near the connector and Type II above the connector. Likely there are three types of metal failure on the inner bracket ear but the initial photo analysis performed for Rev 2.0 was based on the two types observed. Deeper photo analysis was performed, but this concept should help with David’s excellent statement.
Agree it will be interesting to see what the French publish. The Flaperon Failure Analysis (Rev 2.0) does not contain all the analysis otherwise it becomes way too big. The above fatigue comment by David is a very valid and astute statement.
The investigators will have an easy time determining fatigue vs shear regimes on the failure points. However, observation from La Reunion photographs is a greater challenge. Rather than going into a long dissertation on fatigue vs. shear, perhaps the following, conceptual level, explanation sheds some light.
Reference Exhibit 5 on pg 6 of 33 http://www.duncansteel.com/archives/2209
Observe the remains of the Inboard inner bracket ear. In a simple massive shear event there would be only one type of breakage on the inner ear that occurred in a fraction of a second. However on the La Renunion Flaperon Inboard inner bracket ear there are two distinct types of metal failure evident on the inner bracket ear. Type I near the connector and Type II above the connector. Likely there are three types of metal failure on the inner bracket ear but the initial photo analysis performed for Rev 2.0 was based on the two types observed. Deeper photo analysis was performed, but this concept should help with David’s excellent statement.