Figure 8-23 shows a connection using
cap screws. The joint is subjected to a
fluctuating force whose maximum
value is 22.24 kN per screw. The
required data are: cap screw, M16 × 2,
SAE 5; hardened-steel washer, $t_w$ =
1.588 mm thick; steel cover plate, $t_1$ =
15.875 mm, $E_s$ = 207 GPa; and cast-
iron base, $t_2$ = 15.875 mm, $E_{ci}$ = 110
GPa.
(a) Find $k_b$, $k_m$, and $C$ using the
assumptions given in the caption of
Figure 8-23.
(b) Find all factors of safety and
explain what they mean.
Figure 8-23
Pressure-cone frustum
member model for a cap
screw. For this model the
significant sizes are
$l = \begin{cases} h + t_2/2 & t_2 < d\\ h + d/2 & t_2 \ge d \end{cases}$
$D_1 = d + l \tan \alpha = 1.5d + 0.577l$
$D_2 = d_w = 1.5d$
where $l$ = effective grip. The
solutions are for $\alpha = 30^\circ$ and
$d_w = 1.5d.$
