The ratio of the strength of a riveted joint to the strength of original solid plate is called as ________ of the joint.

Explanation:

The efficiency of the riveted joint is defined as the ratio of the strength of the plate in an unpunched condition.

\(\eta = \frac{{Strength\;of\;riveted\;joint}}{{Strength\;of\;unriveted\;solid\;plate}}\)

As the strength of the riveted joint depends on the tearing strength, shearing strength or crushing strength of the joint, the efficiency can be tearing efficiency, shearing efficiency and crushing efficiency.

• Tearing efficiency: Tearing strength of the riveted joint/Strength of the unriveted solid plate

\(\begin{array}{l} {\eta _t} = \frac{{Tearing\;strength}}{{Strength\;of\;solid\;plate}}\\ {\eta _t} = \frac{{\left( {p - d} \right)t\;{\sigma _t}}}{{{p_t}\;{\sigma _t}}} = \frac{{p - d}}{p} \end{array}\)

• Shearing efficiency: Shearing strength of the riveted joint/Strength of the unriveted solid plate

\({\eta _s} = \frac{\pi }{4}\left( {\frac{{{\sigma _s}}}{{{\sigma _t}}}} \right)\left( {\frac{{{d^2}}}{{pt}}} \right)kn\)

k is effective surface area (For double shear, k = 2), n is number of rivets in a pitch length

• Crushing efficiency: Crushing strength of the riveted joint/Strength of the unriveted solid plate

\(\begin{array}{l} {\eta _c} = \frac{{Crushing\;strength}}{{Strength\;of\;solid\;plate}} = \frac{{ndt\;{\sigma _c}}}{{pt\;{\sigma _t}}} = n\left( {\frac{d}{p}} \right)\left( {\frac{{{\sigma _c}}}{{{\sigma _t}}}} \right)\\ \end{array}\)