1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    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!

Method of Joints, Virtual Load

  1. Dec 7, 2014 #1
    Hi I was hoping someone could clear something up for me, I've been set an virtual load (unit load method) question at University, that part of the question I can do however its the calculating the force on the members part that I am struggling with.

    The question asks for all the forces in the members as a function of load P using the unit load method, however as there are 4 pin joints (Ay and Bx can cancel) and 4 bars using any equilibrium, joints or moment calcs I can't get each member only in terms of P.

    Other students have removed members to do this however as this "method" they are using isn't in the course note and I can't find it online I don't want to just assume they are right.

    I've drawn the system In the file uploaded.

    Thanks In Advance


    Attached Files:

  2. jcsd
  3. Dec 7, 2014 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    I think your frame is statically indeterminate. Your classmates are removing members in order to make the resulting determinate. It's much easier to apply the various analysis techniques to a determinate structure, in order to determine the additional equation or equations necessary to allow solution.
  4. Dec 7, 2014 #3
    Okay thanks, I will research this today as I am unfamiliar with the concept.

    Thanks Steamking

    P.S can I message you with a related quire if I have one?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook