Re: Airbus Gust-Load Alleviation systems

From: (brian whatcott)
Organization: Telepath
Date:         07 Sep 96 17:09:14 
References:   1 2 3 4
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In article <airliners.1996.1581@ohare.Chicago.COM>,
>Cracks (and we are talking
>about design for damage tolerance here), grow steadily under
>normal flight loads, but if a big load comes along, either from a
>gust or a big manoeuvre, then as I understand it the material at
>the tip of the crack becomes work-hardened and, as after
>cold-working, is left with a bit of residual compressive stress
>that delays further crack growth.
>So yes, if you don't get large gust loads you will get faster
>crack growth (taken over reasonable time span) and will end up
>with shorter inspection intervals.

Here is my counter-proposal:   <grin>
Any alleviation method needs to sense before acting.
Inevitably, the alleviation broadens the bump spectrum.
Think of this as tending to swap one big bump for three smaller ones.
An obvious fatigue enhancer?

<This represents utter speculation>
brian <>