Introduction to Aircraft Structural Analysis (Elsevier Aerospace Engineering)

610 CHAPTER 22 Wings

Fig.22.22

Shear flow (N/mm) distribution at any station in the wing box of Example 22.7 without cutout.

Fig.22.23

Correction shear flows in the cutout bay of the wing box of Example 22.7.

Wenowconsiderbay②andapplyashearflowof75.9N/mminthewall34intheoppositesense
fromthatshowninFig.22.22.Thisreducestheshearflowinthewall34tozeroand,ineffect,restores
thecutouttobay②.Theshearflowsintheremainingwallsofthecutoutbaywillnolongerbeequivalent
totheexternallyappliedshearloadssothatcorrectionsarerequired.Considerthecutoutbay(Fig.22.23)
withtheshearflowof75.9N/mmappliedintheoppositesensetothatshowninFig.22.22.Thecorrection
shearflowsq′ 12 ,q′ 32 ,andq′ 14 maybefoundusingstatics.Thus,resolvingforceshorizontally,wehave

800 q 12 ′ = 800 ×75.9N

fromwhich

q′ 12 =75.9N/mm

Resolvingforcesvertically,

200 q′ 32 = 50 q′ 12 − 50 ×75.9− 300 q′ 14 =0(i)

andtakingmomentsaboutOinFig.22.21(b),weobtain

2 × 52000 q′ 12 − 2 × 40000 q′ 32 + 2 × 52000 ×75.9− 2 × 60000 q′ 14 =0(ii)