A rectangular beam with semicircular notches, as shown in part b of the figure, has dimensions h = 22 mm and h 1 = 20 mm. The maximum allowable bending stress in the metal beam is xma = 410 MPa, and...

A rectangular beam with semicircular notches, as shown in part b of the figure, has dimensions h = 22 mm and h₁
= 20 mm. The maximum allowable bending stress in the metal beam is

_xma
= 410 MPa, and the bending moment is M = 68 N. m.

Determine the minimum permissible width b
_min
of the beam.