Damage tolerance and fatigue evaluation of composite structure

[lLouie]

Structural components for which the damage tolerance method is shown to be impractical must be shown by component fatigue tests, or analysis supported by tests, to be able to withstand the repeated loads of variable magnitude expected in service. Sufficient component, subcomponent, element, or coupon tests must be done to establish the fatigue scatter factor and the environmental effects. Damage up to the threshold of detectability and ultimate load residual strength capability must be considered in the demonstration.

Which website should I look at doing fatigue test for winglet, canard, wing, airframe? Is there any procedure? or how can damage-tolerance method can be apply for composite structures?

 

[Marekcom]

]Hi,
Airbus methods developped over many years are widely used and recognized as the best for analyzing DAMTOL of composite structures.
regards.

Structural stress Engineer

 

[lLouie]

Can you explain the DAMTOL a bit, plase? I have not heard it before

 

[rb1957]

"DAMTOL" is shorthand for Damage Tolerance (I suspect).

I'm sure there is an FAA AC for damage tolerance analysis of primary composite structure, there are enough planes that use it. The philosophy of damage tolerance can be applied to composites (detect damage before it becomes critical) but I believe that the analysis is very different to metallic structures, and I suspect much more test based ... I suspect you make specimens typical of your structure, with damage, and that this detectable damage (detectable with some inspection technique, possibly a "tap test", possibly ultrasonics) doesn't grow (significantly) within the life of the plane, and supports limit load at the end of the test (residual strength).

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[lLouie]

Thank you so much

 

[Marekcom]

DAMTOL methods of composite structures are based on the BVID theory closely linked to damage mechanics (Kachanov theory).

Structural stress Engineer

 

[rb1957]

is there a EASA AC on this methodology ?

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[Marekcom]

I think so, have you chcked ?

Structural stress Engineer