Questions and discussion for this lecture live here. Fire away by hitting Reply below 
Hello Dr. Sean, I have a question that what should we do if the bar has an inital state like axial load? I thank we should modify the force vector? but how? Thank you~
My first thought is simply to use the transformation matrix to convert the local axial force into global coordinates and apply the force vector to the global force vector. That would be step one…see how you get on and chart your next step from there!
S