Question 16.4: Determine the safe tensile, shear, and bearing loads and the...
Determine the safe tensile, shear, and bearing loads and the efficiency for a 300 mm section of single-riveted lap joint made from ¼ in. plates using six 16-mm-diameter rivets. Assume that the drilled holes are 1.5 mm larger in diameter than the rivets. The values for the design limits for tensile, shear, and bearing stress can be taken as 75, 60, and 131 MPa, respectively.
The safe tensile load, L, based of shear of the rivets is given by
L=n A_{r} \tau_{d}=6 \pi \frac{0.016^{2}}{4} \times 75 \times 10^{6}=90.48 kNThe safe tensile load based on bearing or compressive stress is given by
L=6 \times 0.016 \times 6.35 \times 10^{-3} \times 131 \times 10^{6}=79.86 kNThe safe load based on tensile load is given by L=A_{p} \sigma_{t}.
The area of the plate between the rivet holes, A_p, is given by
A_{p}=0.00635\left(0.3-6\left(16 \times 10^{-3}+1.5 \times 10^{-3}\right)\right)=1.238 \times 10^{-3} m ^{2}L=A_{p} \sigma_{t}=1.238 \times 10^{-3} \times 131 \times 10^{6}=162.2 kN
The safe tensile load would be the least of the three values determined, i.e. L = 79.86 kN.
\eta=\frac{79.86 \times 10^{3}}{0.00635 \times 0.3 \times 75 \times 10^{6}}=0.56The efficiency is 56%.