Calculating Section Modulus for Beam with UDL

[josh16]

Homework Statement

I want to know the section modulus for a beam which has a UDL of 13.5 kn/m across 10 metres. Its simply supported at both ends. max allowable stress = 255 MPa

Homework Equations

Z= M / max allowable stress [cm^3]

The Attempt at a Solution

max bending moment = 13.5 x 10 ^2 / 8 = 168.75 kn/m

168.75 x 10^3 / 255 x 10^6 = 6.617647059 x 10 ^ -4 = 661 cm^3

Thanks,
Josh

 

[SteamKing]

The section modulus is a property of the geometry of the beam's cross-sectional area. What you are calculating is the minimum section modulus which a candidate beam must have in order keep the bending stresses below the max. allowable stress.