A wood beam with cross-sectional dimensions 200 mm × 300 mm is reinforced on its sides by steel plates 12 mm thick (see figure). The moduli of elasticity for the steel and wood are Es= 190 GPa and Ew = 11 GPa, respectively. Also, the corresponding allowable stresses are σs = 110 MPa and σw= 7.5 MPa.
(a) Calculate the maximum permissible bending moment Mmax when the beam is bent about the z axis.
(b) Repeat part a if the beam is now bent about its y axis.
