An engineer is tasked to design the cross-section of a simply supported beam with a length L=3.0 m supporting a uniform load W kN/m. The beam cross-section is composed of four components with similar dimensions of 100 mm width and 30 mm thickness. Two of these components are made of material A and the other two material B, with material properties as shown. Considering two possible arrangements as shown,

Material A B A B B B A A A B Modulus of elasticity 2.8 GPa 1.5 GPa Figure 1. Allowable bending stress 150 MPa 120 MPa