Is Fluid Structure Interaction considered in aircraft design? Fluid Structure Interaction (FSI) causes an  aeroplane’s geometry to change and hence the forces on the different surfaces of an aeroplane become different than the forces expected according to initial calculation.


Is this Fluid Structure Interaction considered while calculating
forces (and hence the final design) of aircraft while finalizing
the designs for aircraft?
If it is considered, what are the available software packages which could be used to analyse this?
Just one example: Good designers put the aileron pushrods away from the elastic axis of the wing to enable the deformation of the wing to create a damping deflection of the ailerons. This is especially helpful for high aspect ratio wings:



When the wing flexes, the pushrod will not be compressed, so will become relatively longer than the surrounding wing structure. This will create a negative aileron deflection which works against the lift force which flexes the wing in the first place. Doing this is particularly helpful in damping wing flutter.

Generally, the engineers make sure that every aircraft component works as intended even when the structure is deformed. Another example: To compensate for differences in the thermal expansion of different components, pushrods in glass fiber fuselages have two halves, connected by a pivoting lever, so that changes in their length will compensate.