Introduction to Aircraft Structural Analysis (Elsevier Aerospace Engineering)

616 CHAPTER 22 Wings

Fig. P.22.5

P.22.6 FigureP.22.6showsasinglysymmetric,two-cellwingsectioninwhichalldirectstressesarecarriedbythe
boomsandshearstressesalonebeingcarriedbythewalls.Allwallsareflatwiththeexceptionofthenoseportion
45.FindthepositionoftheshearcenterSandtheshearflowdistributionforaloadofSy=66750NthroughS.
Tabulatedbelowarelengths,thicknesses,andshearmodulioftheshear-carryingwalls.Notethatdottedline45is
notawall.

Fig. P.22.6

Wall Length (mm) Thickness (mm) G(N/mm^2 ) Boom Area (mm^2 )

34, 56 380 0.915 20700 1, 3, 6, 8 1290

12, 23, 67, 78 356 0.915 24200 2, 4, 5, 7 645

36, 81 306 1.220 24800

45 610 1.220 24800

Nose areaN 1 =51500mm^2.

Ans. xS=160.1mm q 12 =q 78 =17.8N/mm q 32 =q 76 =18.5N/mm

q 63 =88.2N/mm q 43 =q 65 =2.9N/mm q 54 =39.2N/mm

q 81 =90.4N/mm.

P.22.7 Asinglysymmetricwingsectionconsistsoftwoclosedcellsandoneopencell(seeFig.P.22.7).Thewebs
25,34andthewalls12,56arestraight,whileallotherwallsarecurved.Allwallsofthesectionareassumedtobe
effectiveincarryingshearstressesonly,directstressesbeingcarriedbybooms1to6.CalculatethedistancexSof
theshearcenterSaftoftheweb34.TheshearmodulusGisthesameforallwalls.

Ans. 241.4mm.