Introduction to Aircraft Structural Analysis (Elsevier Aerospace Engineering)

13.1 Aircraft Inertia Loads 383

LetNandSbetheaxialandshearloadsatthesectionAA,asshowninFig.13.4.Theinertiaload
actingattheCGofthefuselageaftofAAism 1 a,wherem 1 isthemassofthefuselageaftofAA.Then,

m 1 a=

4.5

g

3 g=13.5kN

Resolvingforcesparalleltotheaxisofthefuselage

N−T+m 1 acos10◦−4.5sin10◦= 0

thatis,

N−137.1+13.5cos10◦−4.5sin10◦= 0

fromwhich

N=124.6kN

Nowresolvingforcesperpendiculartotheaxisofthefuselage

S−m 1 asin10◦−4.5cos10◦= 0

thatis,

S−13.5sin10◦−4.5cos10◦= 0

sothat

S=6.8kN

Notethat,inadditiontotheaxialloadandshearloadatthesectionAA,therewillalsobeabending
moment.
Finally,fromelementarydynamics

v^2 =v^20 + 2 as

Fig.13.4

Shear and axial loads at the section AA of the aircraft of Example 13.1.