Question

Two plates of thickness 5 mm each are joined by double riveted double strap butt joint. Diameter of rivet is 7 mm and clearance between rivet and rivet hole is 1 mm. Pitch of the joint is 28 mm.What is the effeciency of the joint if $S_{yt},S_{ys},and{S}_{yc}$ are 120 MPa, 100MPa & 150 MPa respectively?

• A. 71.42%
• B. 91.5%
• C. 62.5%
• D. 68.32%

Answer 1

The correct option is C 62.5%


$P_s=n\times K\times \frac{\pi }{4}{d}^2\times S_{ys}$ $P_s=2\times 2\times \frac{\pi }{4}\times 7^2\times 100=15.394kN$
$P_c=n\times d\times t{S}_{yc}$
$P_c=2\times 7\times 5\times 150$
$P_c=10500N=10.5kN$
$P_t=(P-d_h)\times t\times S_{y}t$
$d_h=7+1=8mm$
$P_t=12000N=12kN$
$\eta =\frac{min\{P_c,P_s,P_t\}}{P\times t\times S_{yt}}=\frac{10.5}{28\times 5\times 120}=0.625$
$\eta =62.5\%$