Question

Two plates are joined by riveted joint as shown in figure. The permissible stresses in tension, shear and compression are 80, 60 and 120 $120N/m{m}^2$. What is the number of rivets if strength of the plate and the strength of the rivets is equal? Assume that the shear resistance of one rivet in double shear is 1.875 times its resistance in single shear. To calculate the diameter of rivet, the relation is given below


$d=6\sqrt{t}$

Pitch of the rivet is 80 mm

Width of the plate is 250 mm

Thickness of the plate is 30 mm

It is assumed that rivets are so arranged that there is only one rivet in outer row. Also, assume equal pitches along any row.

• A. 8
• B. 7
• C. 6
• D. 5

Answer 1

The correct option is C 6

$d=6\sqrt{t}=6\sqrt{30}=32.863mm$

Shear strength of one rivet

$P_S=1.875(\frac{\pi }{4}\times d^2\tau )$

$P_S=95123.824N$

Crushing strength of one rivet = $\left(dt\right).{\sigma }_C$

$\left(P_C\right)=32.863\times 30\times 120$

= 118306.8 N

Tensile strength of the plate in outer row

$P_t=(w-d)\times t\times {\sigma }_t=(250-32.863)\times 30\times 80$

= 521128.8 N

$\therefore P_s<P_C$

$\therefore 521128.8=n\times 95423.824$

n = 5.46

n = 6