This report describes the work performed by Lockheed Palo Alto Research
Labora- tory, Palo Alto, California 94304. The work was sponsored by Air
Force Office of Scientific Research, Bolling AFB, Washington, D. C.
under Grant F49620-77-C-0l22 and by the Flight Dynamics Laboratory, Air
Force Wright Aeronautical Laboratories, Wright-Patterson AFB, Ohio under
Contract F3361S-76-C-31OS. The work was completed under Task 2307Nl,
"Basic Research in Behavior of Metallic and Composite Components of
Airframe Structures". The work was admini- stered by Lt. Col. J. D.
Morgan (AFOSR) and Dr. N. S. Khot (AFWAL/FIBRA). The contract work was
performed between October 1977 and December 1980. The technical report
was released by the Author in December 1981. Preface Many structures are
assembled from parts which are thin. For example, a stiffened plate or
cylindrical panel is composed of a sheet the thickness of which is small
com- pared to its length, breadth, and stiffener- spacing, and
stiffeners the thickness of which is small compared to their _ heights
and lengths. These assembled structures, loaded in compression, can
buckle overall, that is sheet and stiffeners can collapse together in a
general instability mode; the sheet can buckle locally between
stiffeners; the stiffeners can cripple; and a variety of complex
buckling interactions can occur involving local and overall deformations
of both sheet and stiffeners. More complex, built-up structures can
buckle in more complex and subtle ways.
