A cast-steel C frame as shown in the figure has a rectangular cross section of 1 in by 1.6 in, with a 0.4-in-radius semicircular notch on both sides that forms midflank fluting as shown. Estimate A, rc , rn , and e, and for a load of 3000 lbf, estimate the inner and outer surface stresses at the throat C. Note: Table 3€“4 can be used to determine rn for this section. From the table, the integral f d A/r can be evaluated for a rectangle and a circle by evaluating A/rn for each shape [see Eq. (3€“64)]. Subtracting A/rn of the circle from that of the rectangle yields _ d A/r for the C frame, and rn can then be evaluated

0.4-in R. 1 3000 Ibf 1-in R 0.4 in | | | |+14 in