6-121 A wood beam is reinforced with steel straps at its top and bottom as shown. Determine the maximum bending stress developed in the wood and steel if the beam is sub- jected to a bending moment of M 5 kN m. Sketch the stress distribution acting over the cross section. Take E,, = 11 GPa, Est 200 GPa. 20 mm 300 mm -M = 5 kN-m 200 mm Prob. 6-121 20 mm

Using the CREMONA method, determine the forces and types of stress in the bars and analyze them.

02: The rigid platform has negligible mass and rests on two steel bars, each 250.00 mm long. The center bar is aluminum and 249.90 mm long. Compute the stress in the aluminum bar after the center load P= 400 kN has been applied. For each steel bar, the area is 1200 mm2 and E= 200 GPa. For the aluminum bar, the area is 2400 mm2 and E 70 GPa Rigid platform Steel Ahmum Steel