Composite Beams - Bending Stress - Strengths of Materials

This video shows how to solve for the bending stress of a composite beam. A composite beam is a beam that is made of different materials which of course has different material properties and therefore the bending stress equation cannot be used. In this case, a transformation factor is used to convert the composite beam into a homogeneous beam of the same material to still utilize the same bending stress equation.

(0:00) Composite Beam – Bending Stress
(3:45) Transformation Equations
(6:00) Problem statement: 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 subjected to a bending moment of M = 5 kN-m. Take Ew = 11 GPa and Est = 200 Gpa

[soy]

for calculating the moment of inertia, when you found the moment of inertia of the blocks you were taking away, how come you didn't use the parallel axis theorem to calculate the moment of inertia from the centroid of the total shape?

[Aviator]

So this beam is over engineered. How does one calculate the most optimum (lightest beam) cross section of the beam given the maximum moment?