Applicability of the Southwell Plot to the Interpretation of Test Data From Instability Studies of Shell Bodies

The report demonstrates, from experimental studies, the classic critical loads computed from small displacement theory for perfect shells under ideal loading conditions. The method used is an implicit rather than an explicit one and makes use of the fact that for a realistic structure, the elastic deformation can be associated with the initial displacement from ideal form, the load which produces the motion, and the classic load for the structure.