Structural Loads in Design of Aircraft Components

[yusf]

Hi All;
I am really confused about the application of loads that is either maneuver or aerodynamic loads at the same time or indivudiually while extracting margin of safety for each component under different loads


Could you please guide me in finding MoS...

Maneuver Loads:4G
Aerodynamic Forces and Moments: Fx Fy Fz Mx My Mz..are known

should i apply all those forces at the same time or individualy in ultimat eand limit load calculations?


thanks in advance

 

[rb1957]

i susgest that your manoeurve (4g) is creating the aerodynamic forces, and the aerodynamic forces happen at the same time (simulatneously).

Quando Omni Flunkus Moritati

 

[GregLocock]

There is a gotcha there, more often seen in road vehicles than aero.

The relative sign of the various loads can depend on direction, so while the input from a pothole will be upwards and aft, the inputs from cornering may be - 0 or + at the same time. So you really need to consider what combinations are likely, and examine those, as it is possible that the worst case stress at one location is not caused by +1 +1 +1 loads.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[rb1957]

that's true enough, in that he should consider +ve and -ve manoeuvres.

sometimes we'll conservatively apply max/min envelope loads (ie the largest absolute value applied in both +ve and -ve directions). some OEMs, however, are adament that this is Wrong.

but if he has a specific loadcase, then he should apply those loads directly.

Quando Omni Flunkus Moritati

 

[rb1957]

another thing to remember is that aero. loads are the reactions for the inertia loads ... ie the airplane as a free body has balancing aero. and inertia loads.

Quando Omni Flunkus Moritati