Introduction to Aircraft Structural Analysis (Elsevier Aerospace Engineering)

21.3 Torsion 581

Table 21.2

Skin panel Boom Br(mm^2 ) yr(mm) qb(N/mm)

12 −− − 0

2 3 2 216.6 352.0 −30.3

3 4 3 216.6 269.5 −53.5

4 5 4 216.7 145.8 −66.0

56 5 − 0 −66.0

6 7 6 216.7 −145.8 −53.5

7 8 7 216.6 −269.5 −30.3

8 9 8 216.6 −352.0 0

1 16 1 216.6 381.0 −32.8

16 15 16 216.6 352.0 −63.1

15 14 15 216.6 269.5 −86.3

14 13 14 216.6 145.8 −98.8

13 12 13 − 0 −98.8

12 11 12 216.7 −145.8 −86.3

11 10 11 216.6 −269.5 −63.1

10 9 10 216.6 −352.0 −32.8

fromwhich

qs,0=32.8N/mm(actinginancounterclockwisesense)

Thecompleteshearflowdistributionfollowsbyaddingthevalueofqs,0totheqbshearflowdistribution,
givingthefinaldistributionshowninFig.21.3.Thesolutionmaybecheckedbycalculatingtheresultant
oftheshearflowdistributionparalleltotheCyaxis.Thus,

2[(98.8+66.0)145.8+(86.3+53.5)123.7+(63.1+30.3)82.5

+(32.8− 0 )29.0]× 10 −^3 =99.96kN

whichagreeswiththeappliedshearloadof100kN.Theanalysisofafuselagewhichistaperedalong
itslengthiscarriedoutusingthemethoddescribedinSection20.2andillustratedinExample20.2.

21.3 Torsion................................................................................................

Afuselagesectionisbasicallyasinglecellclosedsectionbeam.Theshearflowdistributionproduced
byapuretorqueisthereforegivenbyEq.(17.1)andis

q=

T

2 A

(21.2)