A simply supported beam $)=(15ft$ is subjected to a uniformly distributed load $w=1\mathrm{.}2ki\frac{p}{f}t.$ The beam is a composite section made from an aluminum alloy $)=(10,600$ksi segment A and a steel $)=(29,000$ksi segment $B$ as shown in Figure $2.$

Figure $2.$ Beam bending stress

uluss$-$sculiun

a$.$ Draw the shear and moment diagrams along the beam length & compute maximum moment.

b$.$ Convert the top aluminum segment into an equivalent rectangular steel section $)=(\frac{E_{al.}}{E_s}$ Determine the location of the centroid and the moment of inertia of the transformed section.

c$.$ Compute the maximum bending stress in the steel material due to $M=405$kip$-$in$.$ Indicate whether this maximum stress in the steel $($lower portion$)$ is a tensile or compressive stress. Draw the section bending stress.