Which riveted joint is having minimum efficiency?

Explanation:

The strength of a rivet joint

• The strength of a rivet joint is measured by its efficiency.
• The efficiency of a joint is defined as the ratio between the strength of a riveted joint to the strength of an un-rivetted joint or a solid plate.
• The efficiency of the riveted joint not only depends upon the size and the strength of the individual rivets but also on the overall arrangement and the type of joints.

Tension: 

Tearing resistance or pull required to tear off the plate per pitch length.

Pt = σt × (p - d) × t

Shear: 

Shearing resistance or pull required to shear off the rivet per pitch length.

\({P_s} = n × \frac{\pi }{4} × {d^2} × \tau \) (single shear)

\({P_s} = n × 2 × \frac{\pi }{4} × {d^2} × \tau\) (double shear)

Crushing: 

Crushing resistance or pull required to crush the rivet per pitch length.

P_c = n × σ_c × d × t

Strength of the riveted joint: Least of Pt, Ps and Pc

Strength of the un-riveted or solid plate per pitch length: P = σt × p × t

The joint efficiency is:

\(\eta = \frac{{min\left( {{P_t},\;{P_s},\;{P_c}} \right)}}{P}\)