Introduction to Aircraft Structural Analysis (Elsevier Aerospace Engineering)

Problems 615

Fig. P.22.3 Fig. P.22.4

P.22.4 Determine the shear flow distribution for a torque of 56500Nm for the three-cell section shown in
Fig.P.22.4.Thesectionhasaconstantshearmodulusthroughout.

Wall Length (mm) Thickness (mm) Cell Area (mm^2 )

12 U 1084 1.220 I 108400

12 L 2160 1.625 II 202500

14, 23 127 0.915 III 528000

34 U 797 0.915

34 L 797 0.915

Ans. q 12 U=25.4N/mm q 21 L=33.5N/mm q 14 =q 32 =8.1N/mm

q 43 U=13.4N/mm q 34 L=5.3N/mm.

P.22.5 The idealized cross section of a two-cell thin-walled wing box is shown in Fig. P.22.5. If the wing box
supportsaloadof44500Nactingalongtheweb25,calculatetheshearflowdistribution.TheshearmodulusGis
thesameforallwallsofthewingbox.

Ans. q 16 =33.9N/mm q 65 =q 21 =1.1N/mm

q 45 =q 23 =7.2N/mm q 34 =20.8N/mm

q 25 =73.4N/mm.

Wall Length (mm) Thickness (mm) Boom Area (mm^2 )

16 254 1.625 1, 6 1290

25 406 2.032 2, 5 1936

34 202 1.220 3, 4 645

12, 56 647 0.915

23, 45 775 0.559

Cell areas:AI=232000mm^2 ,AII=258000mm^2.