The lecture starts off with a video of a fatigue shear test of a stiffened plate which displays how the buckling modes will change as the mechanical properties degrade due to stiffener separation. From this a discussion on post buckling behavior of a structure ensues.

The Von Karman equations are then used to find an analytical expression for the post buckling behavior. After the derivation the results are used to define the ‘effective width’ of a post buckled plate. The lecture is concluded with an explanation of the second homework assignment.