Introduction to Aircraft Structural Analysis (Elsevier Aerospace Engineering)

Problems 107

and

1 δD,h=

880 × 106

200000 × 1800

whichgives

δD,h=2.44mm

Both deflections are positive, which indicates that the deflections are in the directions of the applied
unitloads.Notethatinthepreceding,itisunnecessarytospecifyunitsfortheunitloadsincetheunit
loadappears,ineffect,onbothsidesofthevirtualworkequation(theinternalF 1 forcesaredirectly
proportionaltotheunitload).

Reference

[1] Megson,T.H.G.,StructuralandStressAnalysis,2ndedition,Elsevier,2005.

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

P.4.1 Use the principle of virtual work to determine the support reactions in the beam ABCD shown in
Fig.P.4.1.

Ans. RA=1.25WRD=1.75W.

Fig. P.4.1

P.4.2 FindthesupportreactionsinthebeamABCshowninFig.P.4.2usingtheprincipleofvirtualwork.

Ans. RA=(W+ 2 wL)/ 4 Rc=( 3 w+ 2 wL)/4.