1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Section modulus

  1. Dec 17, 2013 #1
    1. The problem statement, all variables and given/known data

    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

    2. Relevant equations

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

    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

  2. jcsd
  3. Dec 17, 2013 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    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.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted