Introduction to Aircraft Structural Analysis (Elsevier Aerospace Engineering)

11.4 Connections 367

Fig.11.13

A group-riveted joint.

11.4.4 Eccentrically Loaded Riveted Joints

The bracketed connection shown in Fig. 11.14 carries a loadPoffset from the centroid of the rivet

group.TherivetgroupisthensubjectedtoashearloadPthroughitscentroidandamomentortorque

Peaboutitscentroid.

ItisassumedthattheshearloadPisdistributedequallyamongtherivets,causingashearforcein

eachrivetparalleltothelineofactionofP.ThemomentPeisassumedtoproduceashearforceSin

eachrivet,whereSactsinadirectionperpendiculartothelinejoiningaparticularrivettothecentroid

oftherivetgroup.Furthermore,thevalueofSisassumedtobeproportionaltothedistanceoftherivet

fromthecentroidoftherivetgroup.Then

Pe=

∑

Sr

IfS=kr,wherekisaconstantforallrivets,then

Pe=k

∑

r^2

fromwhich k=Pe

/∑

r^2

and

S=

Pe

∑

r^2

r (11.6)

TheresultantforceonarivetisthenthevectorsumoftheforcesduetoPandPe.

Example 11.2

ThebracketshowninFig.11.15carriesanoffsetloadof5kN.Determinetheresultantshearforcesin

therivetsAandB.

The vertical shear force on each rivet is 5/6=0.83kN. The moment (Pe) on the rivet group is

5 × 75 =375kNmm.ThedistanceofrivetA(andB,G,andH)fromthecentroidCoftherivetgroupis