This lecture is a continuation on the previous lecture, where Prof. C. Kassapoglou talks about stiffened skin structures in more detail. Unfortunately the recording of this lecture was missing, so a part of an older lecture is presented, containing the first half of the material.

The first subject that is covered is the equivalent stiffness that can be calculated for different cases of loading, one being the equivalent membrane stiffness, the other the bending stiffness. Different cases are then explained for which these stiffnesses, or a combination of them, should be used.

Next an overview will be given of all the different failure modes for a stiffened panel, and the solution methods that have been derived to calculate them. Finally the panel breaker condition is defined, which can be used to couple different failure modes to eachother, significantly reducing the complexity of the solutions found using a reasonably general assumption.

The rest of the material covers total panel buckling, combined skin and stiffener buckling, and design optimization for the combined case. This material is not covered in the recording, but can be found in the lecture slides.