Introduction to Aircraft Structural Analysis (Elsevier Aerospace Engineering)

Problems 521

fromwhich

s1,0=16.96mm

sothatapointofzerowarpingoccursinthewall12atadistanceof8.04mmfromthepoint2asbefore.
Intheweb23,letthepointofzerowarpingoccurats 2 =s2,0.Then

2 ×

1

2

× 25 × 25 − 2 ×

1

2

×8.04s2,0= 424

whichgivess2,0=25mm(i.e.,ontheaxisofsymmetry).Clearly,fromsymmetry,afurtherpointofzero
warpingoccursintheflange34atadistanceof8.04mmfromthepoint3.Thewarpingdistributionis
thenobtaineddirectlyusingEq.(17.20)inwhich

AR=AR,O−A′R

Problems..............................................................................................

P.17.1 Auniform,thin-walled,cantileverbeamofclosedrectangularcrosssectionhasthedimensionsshownin
Fig. P.17.1. The shear modulusGof the top and bottom covers of the beam is 18000N/mm^2 , while that of the
verticalwebsis26000N/mm^2.

Fig. P.17.1